AeroElectric-Archive.digest.vol-er
July 30, 2005 - August 10, 2005
>>>
>>>
>>ILS,
>>
>>
>>>the TN200D only displays the GS. The GNS430 is rock solid out and
>>>inbound.
>>>
>>>
>>The
>>
>>
>>>old TN200 did not have this problem; it and the GNS430 were working fine.
>>>Also, now the Terra TN200D will not display the CDI for the VOR unless
>>>I'm
>>>
>>>
>>almost
>>
>>
>>>on the airport; VOR on airport. The TRI-NAV is wired to display the OBS
>>>
>>>
>>setting
>>
>>
>>>as well as the radial currently on. This works OK, meaning the CDI is
>>>
>>>
>>getting
>>
>>
>>>the correct data.
>>>The only explanation I can come up with, is that the TN200D is less
>>>
>>>
>>sensitive than
>>
>>
>>>the old TN200 and outbound the "rabbit ears" antenna, oriented with the
>>>
>>>
>>"ears"
>>
>>
>>>facing aft and under the tailcone has better reception going away from
>>>the
>>>ILS. This is weird; all airplanes I have seen have the VOR antenna
>>>
>>>
>>"facing"
>>
>>
>>>aft. In addition I was told by an avionics shop that dual VOR/ILS
>>>
>>>
>>typically use
>>
>>
>>>a 1-into-4 quadaplexer, rather than two VOR antennas..
>>>Has anyone experienced like symtoms??
>>>Wayne
>>>
________________________________________________________________________________
| From: | "Wayne Sweet" <w_sweet(at)comcast.net> |
| Subject: | Re:A Bugger of an Avionics Problem |
Correct. The only remaining component is the antenna. Since the ILS displays
strong OUTBOUND as far as 30 miles, but on inbound and only when very near
the LOC center, the LOC CDI indicator drops out. The same happens with the
VOR CDI most of the time. I will check the balum on the "rabbit ears"
antenna, in the event some corrosion has built up to the point that a split
signal is too weak for the TN200D, but NOT for the GNS430 ILS. It is strong
anywhere within 30 miles of the ILS airport.
Hate to have to crawl into the tailcone to access this grounding point.
Wayne
----- Original Message -----
From: "Charlie England" <ceengland(at)bellsouth.net>
Subject: Re: AeroElectric-List: Re:A Bugger of an Avionics Problem
>
>
> Seems pretty unlikely that all would have exactly the same problem. Can
> you swap antenna cables at the radio trays, fly & try it? Ohm meter
> checks of coax will detect only gross problems like DC shorts between
> center & ground. If you can't swap antennas, rig up a cable with a
> 'rubber ducky' & try that to see if you have a different symptom.
>
> Another possibility is that the radios aren't seating all the way into
> the tray or the connector. Are you screwing in the chassis retaining
> screw all the way & making sure that radio goes all the way into the
> tray? Is this the version of the Terra with 2 separate radios + the
> 'trinav' head? If so, there are several opportunities for
> poor/intermittant connections at the various connectors. Slight
> variations in connector mounting & chassis cutouts can prevent the sub-d
> connectors from seating all the way & lead to truly bizarre symptoms.
> The same thing applies to the mating coax connectors between the radios
> & the tray. If the tray has shifted in the instrument panel, or if the
> new radios have trim bezels from a different batch/mfgr, or , the
> radio might not be going all the way into the tray.
>
> Charlie
>
> Wayne Sweet wrote:
>
>>
>>
>>Peter,
>>Thanks for the reply. I replaced the coax at the tray, using new TED
>>connectors rather than the funky Terra ones. I have done lots of avionics
>>wiring and learned to continuity check all coax connectors. These are
>>fine.
>>The same problem occurs when I plug in a second (and 3rd) TN200D. I bought
>>3
>>Terra NAV/COM on eBay, so have some that will be going up on eBay,
>>starting
>>this afternoon.
>>The problem is the same for all 3 TN200D. The coax connections and
>>continuity are fine.
>>Very puzzling.
>>Wayne
>>----- Original Message -----
>>From: "Peter Davidson" <pdavidson(at)familynet.net>
>>To:
>>Subject: AeroElectric-List: Re:A Bugger of an Avionics Problem
>>
>>
>>
>>
>>>
>>>
>>>Wayne,
>>>I'm not familiar with the TX760/TN200D system, but it sounds like two
>>>possibilities to me.
>>>1) If the harness had to be rewired at all for the new components,
>>>there's
>>>a
>>>good possibility that the coax might have been accidentally yanked on or
>>>something to cause problems with the connection.
>>>2) If the new components were direct replacements, I 'd say it's a
>>>defective
>>>TN200D.
>>>-Peter
>>>
>>>
>>>
>>>
>>>>I have dual VOR/ILS's; a GNS430 and a recently installed replacement
>>>>
>>>>
>>>TX760/TN200D.
>>>
>>>
>>>>The VOR/GS is taken from a single VOR antenna through a 1 into 4
>>>>splitter.
>>>>The Terra is a replacement for an older TX720/TN200, which function
>>>>well,
>>>>
>>>>
>>>except
>>>
>>>
>>>>for a squelch problem that Toronto Avionics fixed. I sold that system on
>>>>
>>>>
>>>eBay.
>>>
>>>
>>>>Anyway, this "new" Terra will not consistantly display the CDI for
>>>>VOR/LOC
>>>>
>>>>
>>>EXCEPT
>>>
>>>
>>>>when outbound from the ILS. Then I get turned around and inbound on the
>>>>
>>>>
>>>ILS,
>>>
>>>
>>>>the TN200D only displays the GS. The GNS430 is rock solid out and
>>>>inbound.
>>>>
>>>>
>>>The
>>>
>>>
>>>>old TN200 did not have this problem; it and the GNS430 were working
>>>>fine.
>>>>Also, now the Terra TN200D will not display the CDI for the VOR unless
>>>>I'm
>>>>
>>>>
>>>almost
>>>
>>>
>>>>on the airport; VOR on airport. The TRI-NAV is wired to display the OBS
>>>>
>>>>
>>>setting
>>>
>>>
>>>>as well as the radial currently on. This works OK, meaning the CDI is
>>>>
>>>>
>>>getting
>>>
>>>
>>>>the correct data.
>>>>The only explanation I can come up with, is that the TN200D is less
>>>>
>>>>
>>>sensitive than
>>>
>>>
>>>>the old TN200 and outbound the "rabbit ears" antenna, oriented with the
>>>>
>>>>
>>>"ears"
>>>
>>>
>>>>facing aft and under the tailcone has better reception going away from
>>>>the
>>>>ILS. This is weird; all airplanes I have seen have the VOR antenna
>>>>
>>>>
>>>"facing"
>>>
>>>
>>>>aft. In addition I was told by an avionics shop that dual VOR/ILS
>>>>
>>>>
>>>typically use
>>>
>>>
>>>>a 1-into-4 quadaplexer, rather than two VOR antennas..
>>>>Has anyone experienced like symtoms??
>>>>Wayne
>>>>
>
>
>
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: Summing up OVP |
I don't think anyone has spoken of any failure mode that would justify
case 2. I believe a B-lead contactor has only been proposed in
conjunction with an internal VR alternator.
Ken
bakerocb(at)cox.net wrote:
>
>AeroElectric-List message previously posted by: Richard Riley
>
>
><<..........skip.......The problem is X
>It can occur when using equipment Y, under the following conditions -
>If you use equipment Z instead, it won't happen......skip.......>>
>
>7/30/2005
>
>Hello Richard, I think that your questions are right on target. I'd like to
>take a layman's whack at answering them:
>
>A) "The problem is X"
>
>The problem is potential damage to an aircraft's electrical, avionics, or
>instrument components from an alternator that is putting out excessive
>voltage.
>
>B) "It can occur when using equipment Y......"
>
>It can occur when using either an internally regulated or an externally
>regulated field controlled alternator or a permanent magnet alternator.
>
>C) "under the following conditions"
>
>When the voltage regulator (either external or internal) or the alternator
>suffers a fault that causes the over voltage condition.
>
>D) "If you use equipment Z instead, it won't happen"
>
>There is no way to guarantee that, "it", the over voltage condition, will
>never happen with any type of regulator or alternator. So the discussion
>moves onto the ongoing thread of how to best protect an aircraft's
>electrical, avionics, or instrument components from an alternator that is
>putting out excessive voltage.
>
>1) Case one: Use an externally regulated field controlled alternator and a
>mechanism that when an over voltage conditon is detected cuts off the field
>current to the field controlled alternator.
>
>2) Case two: But what if one doesn't feel that just cutting off the field
>current provides adequate protection? Then put a separate cut off mechanism
>in the externally regulated alternator's output B (for battery) lead that
>opens up that lead in time to protect the components at risk.
>
>3) Case three: But what if the voltage gets so high so quickly that the
>separate B lead cut off mechanism cannot do its job in time? How high and
>how quick and the best kind of B lead cut off mechanism is what the ongoing
>thread is all about.
>
>4) Case four: Use an internally regulated alternator and depend upon the
>internal regulator to not permit an over voltage condition.
>
>5) Case five: But what if the internal regulator fails to provide adequate
>protection? Then put a separate cut off mechanism in the internally
>regulated alternator's output B (for battery) lead that opens up that lead
>in time to protect the components at risk.
>
>6) Case six: But what if the voltage gets so high so quickly that the
>separate B lead cut off mechanism cannot do its job in time? How high and
>how quick and the best kind of B lead cut off mechanism is what the ongoing
>thread is all about.
>
>7) Case seven: Use a permanent magnet alternator and put a separate cut off
>mechanism in the permanent magnet alternator's output B (for battery) lead
>that opens up that lead in time to protect the components at risk.
>
>8) Case eight: But what if the voltage gets so high so quickly that the
>separate B lead cut off mechanism cannot do its job? How high and how quick
>and the best kind of B lead cut off mechanism is what the ongoing thread is
>all about.
>
>So where should one's comfort level reside? Mine stops at Case one, but I am
>not trying to push that down any one's throat.
>
>OC
>
>
>
>
________________________________________________________________________________
| From: | "Thomas Johnson" <trj01(at)comcast.net> |
| Subject: | Re: Summing up OVP |
>
> >I don't think anyone has spoken of any failure mode that would justify
> >case 2. I believe a B-lead contactor has only been proposed in
> >conjunction with an internal VR alternator.
> >Ken
>
This is my understanding as well. There are really only two "lightning rod" issues
here:
1) Crowbar disconnect method VS other methods
a) AEC has recommended the crowbar method for shutting down both internally and
externally regulated alternators.
b) Some say that the crowbar method is outdated and that there are better ways
to implement this function.
c) Some say that the crowbar method is hazardous due to the low internal resistance
of modern batteries.
d) I have yet to see a published schematic for any alternative to the AEC crowbar
module.
e) False triggering will be an "issue of scrutiny" with any disconnect method.
2) B-Lead disconnect & load dump issues
a) AEC has recommended a B-lead overvoltage disconnect ONLY for internally regulated
alternators.
b) It has been shown that a B-lead disconnect can cause a "load dump" event.
c) It has been shown that a load dump event can damage some alternators.
d) It has been claimed that the installation of Transorbs in the right places
can mitigate this problem.
Tom Johnson
________________________________________________________________________________
| Subject: | Re: Summing up OVP |
| From: | "John Schroeder" <jschroeder(at)perigee.net> |
Tom -
That also has been my understanding of the thread - in much more vague
terms than you so clearly describe. Thanks for the great summary.
John Schroeder
>
> This is my understanding as well. There are really only two "lightning
> rod" issues here:
>
> 1) Crowbar disconnect method VS other methods
>
> a) AEC has recommended the crowbar method for shutting down both
> internally and externally regulated alternators.
> b) Some say that the crowbar method is outdated and that there are
> better ways to implement this function.
> c) Some say that the crowbar method is hazardous due to the low
> internal resistance of modern batteries.
> d) I have yet to see a published schematic for any alternative to the
> AEC crowbar module.
> e) False triggering will be an "issue of scrutiny" with any disconnect
> method.
>
> 2) B-Lead disconnect & load dump issues
>
> a) AEC has recommended a B-lead overvoltage disconnect ONLY for
> internally regulated alternators.
> b) It has been shown that a B-lead disconnect can cause a "load dump"
> event.
> c) It has been shown that a load dump event can damage some
> alternators.
> d) It has been claimed that the installation of Transorbs in the right
> places can mitigate this problem.
>
> Tom Johnson
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
AeroElectric-List message previously posted by: "Thomas Johnson"
<<.......skip....... There are really only two "lightning rod" issues
here:
1) Crowbar disconnect method VS other methods......skip.....>>
7/31/2005
Hello Tom, Thanks for your input. The term "crowbar disconnect method" has a
dramatic, violent, attention getting, and definitive connotation to it, but
it is completely non descriptive in terms of what is doing what to what.
I'll bet there are dozens of readers just like me that don't know what the
method actually consists of. Would you, or some other contributor, please
just describe the method in simple layman's terms?
I hesitate to suggest such a disruptive change in the use of a term that,
through repitition, has become engraved in our consciousness, if not our
understanding, but think of the value in increased understanding of using
instead a phrase such as "the frammis on the whoosis" method.
OC
PS: And I really hate to nit pick here, but my layman's brain associates the
term "crowbar method" as just an initiating or multiple step process that
can lead to ending the undesired output of an alternator. To actually
accomplish an alternator disconnect (opening the B lead), however,requires
some additional, and apparently rather controversial, hardware.
PPS: Deliberate or not, I like your "lightning rod" pun.
________________________________________________________________________________
| Subject: | Re: Summing up OVP |
On 30 Jul 2005 at 23:30, Thomas Johnson wrote:
>
>
> >>
> 1) Crowbar disconnect method VS other methods
>
> a) AEC has recommended the crowbar method for shutting down both
> internally and externally regulated alternators. b) Some say that
> the crowbar method is outdated and that there are better ways to
> implement this function. c) Some say that the crowbar method is
> hazardous due to the low internal resistance of modern batteries. d)
> I have yet to see a published schematic for any alternative to the
> AEC crowbar module. e) False triggering will be an "issue of
> scrutiny" with any disconnect method.
>
>IMHO, there is always more than one method for tackling this problem. However,
I knew nothing about
wiring an airplane until I came across Bob's book a few years ago. As a result,
I have wired a Velocity and
soon my RV9A. Bob at least has attempted to provide me(us) with a method. I can
understand a company
or would be enterprise who is selling a device to "crowbar" an alternator might
not want to share their
schematic with the list. But I think it would be helpful to explain there methodology
and rudimentary circuit
design.
Peter Laurence
Peter Laurence
RV9A wings
________________________________________________________________________________
| From: | rd2(at)evenlink.com |
| Subject: | traffic scope antenna |
Hi all,
For a recently purchased traffic scope I would like to install a fixed
antenna.
The airplane already has 2 shark fin antennae (one for the transponder and
one for the DME).
1) Does anyone have a good source of shark fins (meaning good price and
SWR)? I may have to replace one of the existing shark fins (coating
cracked) and add another for the traffic scope.
2) How far from the existing shark fins should I install the antenna for
the traffic scope? Any possible interference (e.g. from the DME?)
3) Is a less expensive solution appropriate (ebay monopole for $16.95 -
http://search.ebay.com/transponder-antenna_W0QQfkrZ1QQfromZR8) ?
Advantages/disadvantages of such monopole?
Rumen
________________________________________________________________________________
| From: | Jim Oke <wjoke(at)shaw.ca> |
Taking a further step back, the OVP "discussion" comes down to a cost vs.
benefit vs. risk analysis.
Thus:
A) most modern OBAM aircraft need a power source to run radios, EFIS, GPS,
engine instruments, etc.
B) the power source is most commonly an engine driven alternator.
C) choices in alternators are low production volume (= high cost)
specialized aviation units vs. mass-produced (= relatively low cost)
automotive units, the latter also often having size/weight advantages as
well.
D) numberous factors go into the cost/benefit analysis of this choice.
E) part of this choice is a risk analysis done to anticipate failue modes(s)
and decide what sorts of protective/back-up devices should be added to the
system to protect against particular modes.
F) the risk analysis involves partly safety of flight issues and partly
dollar costs.
So that's how people have arrived at Case 5 and the "debate" about providing
a cost effective over voltage protection stated in worst "worst case" terms
as Case 6.
Part of case 6 seems to be about protecting the alternator against damage
during a possible "load dump" event during some failures. Given that the
automotive alternators we are talking about are in the $100-$200 cost range,
and that the avionics in some aircraft are approaching the $10,000 range
(Garmin 430s, etc.), then (to myself) the alternator can be regarded as a
throwaway "fuse" to protect the much more costly avionics in a complex OBAM
aircraft.
In my own "built to a budget" aircraft (basic VFR instruments, basic engine
instruments, basic VHF & TPNDR avionics) it made no sense to spend $800 to
power $1500 worth of avionics so I went with a low cost automotive
alternator and spent the $25 to build a "homebrew" OVP device. This was a
sensible cost vs. benefit vs. risk analysis to me. I consider there are no
"safety of flight" alternator failure issues in my plain jane VFR RV-6A.
As in many things in life, you pay your money, you make your choices, and
you live with the associated risks.
Jim Oke
Wpg., MB
RV-6A, RV-3
> -----Original Message-----
> From: owner-aeroelectric-list-server(at)matronics.com
> [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Ken
> Sent: July 30, 2005 10:13 PM
> To: aeroelectric-list(at)matronics.com
> Subject: Re: AeroElectric-List: Summing up OVP
>
>
> I don't think anyone has spoken of any failure mode that
> would justify case 2. I believe a B-lead contactor has only
> been proposed in conjunction with an internal VR alternator.
> Ken
>
> bakerocb(at)cox.net wrote:
>
> >
> >AeroElectric-List message previously posted by: Richard Riley
> >
> >
> ><<..........skip.......The problem is X It can occur when using
> >equipment Y, under the following conditions - If you use equipment Z
> >instead, it won't happen......skip.......>>
> >
> >7/30/2005
> >
> >Hello Richard, I think that your questions are right on target. I'd
> >like to take a layman's whack at answering them:
> >
> >A) "The problem is X"
> >
> >The problem is potential damage to an aircraft's electrical,
> avionics,
> >or instrument components from an alternator that is putting out
> >excessive voltage.
> >
> >B) "It can occur when using equipment Y......"
> >
> >It can occur when using either an internally regulated or an
> externally
> >regulated field controlled alternator or a permanent magnet
> alternator.
> >
> >C) "under the following conditions"
> >
> >When the voltage regulator (either external or internal) or the
> >alternator suffers a fault that causes the over voltage condition.
> >
> >D) "If you use equipment Z instead, it won't happen"
> >
> >There is no way to guarantee that, "it", the over voltage condition,
> >will never happen with any type of regulator or alternator. So the
> >discussion moves onto the ongoing thread of how to best protect an
> >aircraft's electrical, avionics, or instrument components from an
> >alternator that is putting out excessive voltage.
> >
> >1) Case one: Use an externally regulated field controlled alternator
> >and a mechanism that when an over voltage conditon is
> detected cuts off
> >the field current to the field controlled alternator.
> >
> >2) Case two: But what if one doesn't feel that just cutting off the
> >field current provides adequate protection? Then put a
> separate cut off
> >mechanism in the externally regulated alternator's output B (for
> >battery) lead that opens up that lead in time to protect the
> components at risk.
> >
> >3) Case three: But what if the voltage gets so high so
> quickly that the
> >separate B lead cut off mechanism cannot do its job in time?
> How high
> >and how quick and the best kind of B lead cut off mechanism
> is what the
> >ongoing thread is all about.
> >
> >4) Case four: Use an internally regulated alternator and depend upon
> >the internal regulator to not permit an over voltage condition.
> >
> >5) Case five: But what if the internal regulator fails to provide
> >adequate protection? Then put a separate cut off mechanism in the
> >internally regulated alternator's output B (for battery) lead that
> >opens up that lead in time to protect the components at risk.
> >
> >6) Case six: But what if the voltage gets so high so quickly
> that the
> >separate B lead cut off mechanism cannot do its job in time?
> How high
> >and how quick and the best kind of B lead cut off mechanism
> is what the
> >ongoing thread is all about.
> >
> >7) Case seven: Use a permanent magnet alternator and put a
> separate cut
> >off mechanism in the permanent magnet alternator's output B (for
> >battery) lead that opens up that lead in time to protect the
> components at risk.
> >
> >8) Case eight: But what if the voltage gets so high so
> quickly that the
> >separate B lead cut off mechanism cannot do its job? How
> high and how
> >quick and the best kind of B lead cut off mechanism is what
> the ongoing
> >thread is all about.
> >
> >So where should one's comfort level reside? Mine stops at
> Case one, but
> >I am not trying to push that down any one's throat.
> >
> >OC
> >
> >
> >
> >
>
>
> Photoshare, and much much more:
>
>
>
>\]
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: crowbar method |
I'll take a stab at this. Crowbar just means that when the Overvoltage
trips the SCR, the SCR shorts out the power.( Kind of like throwing a
crowbar across the battery to short things out.) That immediately starts
dropping the voltage (a good thing) and the current flow through the CB
trips the CB to permanently shutdown the alternator.
The SCR causes a significant momentary current flow or pulse from the
battery through the CB. There have been some (unsubstantiated in my
opinion) allegations that it could be harmful in vague ways. No
circuitry to do this any other way has been presented by anyone here as
far as I know however one person here does sell an alternative product
for shutting things down.
I don't think there is much controversy over the method of opening a B
lead connection for an internal VR alternator. We seem to know that a
standard $15. battery contactor is simply not guranteed to do this
reliably as the voltage may climb way above 12 volts and cause contact
arcing.
I'm sticking with the crowbar and the advantage of feedback on its
performance from other list members. So far I have yet to purchase an
aviation related electronic device that hasn't required modification,
repair, or information in addition to what the manufacturer provided so
I put a high value on understanding what I use and feedback from this list.
Ken
bakerocb(at)cox.net wrote:
>
>AeroElectric-List message previously posted by: "Thomas Johnson"
>
>
><<.......skip....... There are really only two "lightning rod" issues
>here:
>
>1) Crowbar disconnect method VS other methods......skip.....>>
>
>7/31/2005
>
>Hello Tom, Thanks for your input. The term "crowbar disconnect method" has a
>dramatic, violent, attention getting, and definitive connotation to it, but
>it is completely non descriptive in terms of what is doing what to what.
>
>I'll bet there are dozens of readers just like me that don't know what the
>method actually consists of. Would you, or some other contributor, please
>just describe the method in simple layman's terms?
>
>I hesitate to suggest such a disruptive change in the use of a term that,
>through repitition, has become engraved in our consciousness, if not our
>understanding, but think of the value in increased understanding of using
>instead a phrase such as "the frammis on the whoosis" method.
>
>OC
>
>PS: And I really hate to nit pick here, but my layman's brain associates the
>term "crowbar method" as just an initiating or multiple step process that
>can lead to ending the undesired output of an alternator. To actually
>accomplish an alternator disconnect (opening the B lead), however,requires
>some additional, and apparently rather controversial, hardware.
>
>PPS: Deliberate or not, I like your "lightning rod" pun.
>
>
________________________________________________________________________________
| From: | "John Swartout" <jgswartout(at)earthlink.net> |
OC, Jim Weir wrote a nice column explaining what a crowbar circuit does
and how to fashion one in the September '01 KITPLANES. If you don't
have the magazine, you can read the article here:
http://www.rst-engr.com/kitplanes/KP0109/KPtext.pdf
John
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
bakerocb(at)cox.net
Subject: AeroElectric-List: crowbar method
AeroElectric-List message previously posted by: "Thomas Johnson"
<<.......skip....... There are really only two "lightning rod" issues
here:
1) Crowbar disconnect method VS other methods......skip.....>>
7/31/2005
Hello Tom, Thanks for your input. The term "crowbar disconnect method"
has a
dramatic, violent, attention getting, and definitive connotation to it,
but
it is completely non descriptive in terms of what is doing what to what.
I'll bet there are dozens of readers just like me that don't know what
the
method actually consists of. Would you, or some other contributor,
please
just describe the method in simple layman's terms?
I hesitate to suggest such a disruptive change in the use of a term
that,
through repitition, has become engraved in our consciousness, if not our
understanding, but think of the value in increased understanding of
using
instead a phrase such as "the frammis on the whoosis" method.
OC
PS: And I really hate to nit pick here, but my layman's brain associates
the
term "crowbar method" as just an initiating or multiple step process
that
can lead to ending the undesired output of an alternator. To actually
accomplish an alternator disconnect (opening the B lead),
however,requires
some additional, and apparently rather controversial, hardware.
PPS: Deliberate or not, I like your "lightning rod" pun.
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: crowbar method |
>I'll take a stab at this. Crowbar just means that when the Overvoltage
trips the SCR, the SCR shorts out the power.( Kind of like throwing a
crowbar across the battery to short things out.) That immediately starts
dropping the voltage (a good thing) and the current flow through the CB
trips the CB to permanently shutdown the alternator.
Correct. However, the circuit breaker is not rated for this abuse. Nor is
adding a small resistor to bring the currents down simple (see earlier
posts), since pulse resistors are a special breed.
>The SCR causes a significant momentary current flow or pulse from the
battery through the CB. There have been some (unsubstantiated in my
opinion) allegations that it could be harmful in vague ways.
Unsubstantiated allegations? The circuit breaker is not rated for the
current. It is the designer's responsibilty to make sure the design meets
the requirement. To use the term "unsubstantiated allegations" seems very
strange when discussing merely technical performance. The "allegations" are
very much substantiated. The circuit breaker won't do the job. Look it up.
>No circuitry to do this any other way has been presented by anyone here as
>far as I know however one person here does sell an alternative product for
>shutting things down.<
I am that person. Since I sell a part called the Linear Over Voltage Module,
I don't want to release the schematic, but I will tell you it uses a LTC1696
available only in an SOT-23-6 package that is not suitable for most builders
to assemble. "Linear" (non-crowbar) OVPs aren't hard to design but they have
5 mosfets and 20 other parts. But the important point is that the LOVM just
cuts off the field current. This is the preferred method. Let me slop a
pearl....nobody has used a crowbar for this application in 30 years.
>I don't think there is much controversy over the method of opening a B lead
>connection for an internal VR alternator. We seem to know that a standard
>$15 battery contactor is simply not guranteed to do this reliably as the
>voltage may climb way above 12 volts and cause contact arcing.<
True. The Kilovac "Czonka III" EV200AAANA is the contactor that will do the
job and has a 100 mA coil as a bonus. (I have a few of these cheap if you
contact me offlist.)
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
(508) 764-2072
"I tried being reasonable, I didn't like it."
---Clint Eastwood
________________________________________________________________________________
| From: | Kevin Horton <khorton01(at)rogers.com> |
| Subject: | Re: crowbar method |
>
>
>
>> I'll take a stab at this. Crowbar just means that when the
>> Overvoltage
>>
> trips the SCR, the SCR shorts out the power.( Kind of like throwing a
> crowbar across the battery to short things out.) That immediately
> starts
> dropping the voltage (a good thing) and the current flow through
> the CB
> trips the CB to permanently shutdown the alternator.
>
> Correct. However, the circuit breaker is not rated for this abuse.
> Nor is
> adding a small resistor to bring the currents down simple (see earlier
> posts), since pulse resistors are a special breed.
>
>
>> The SCR causes a significant momentary current flow or pulse from the
>>
> battery through the CB. There have been some (unsubstantiated in my
> opinion) allegations that it could be harmful in vague ways.
>
> Unsubstantiated allegations? The circuit breaker is not rated for the
> current. It is the designer's responsibilty to make sure the design
> meets
> the requirement. To use the term "unsubstantiated allegations"
> seems very
> strange when discussing merely technical performance. The
> "allegations" are
> very much substantiated. The circuit breaker won't do the job. Look
> it up.
>
>
The CB specs provide an envelope of conditions under which the CB
should perform as advertised, repeatedly - i.e. it will trip within a
certain time, at a certain tolerance to the advertised trip current.
But the spec sheet doesn't say what will happen if it is operated at
other conditions. It doesn't say how its performance will be
affected. So how do we know it won't do the job? Is there evidence
that it won't do the job, or is the statement "the circuit breaker
won't do the job" simply an unsubstantiated allegation?
I'd love to see the test results that show the CB in a crowbar OVP
won't do the job. Bob has described tests he has down that show the
CB will do the job, and the only complaints from the field seem to be
some installations that are prone to nuisance trips. The later
variants of the design are reputed to be less prone to nuisance trips.
If we operate the CB outside its rated current repeatedly, this could
possibly affect the current at which the CB will open. But, the
exact value at which it opens isn't important in this application.
Normally there is very little current through the CB. If there is an
overvoltage, and the OVP trips, there will be a very large current
though the CB. We only need the CB to differentiate between a very
small current, and a very large one. It doesn't matter exactly what
its trip point is.
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: crowbar method |
This is where we disagree I guess Eric.
Circuit breakers are used to interupt an overcurrent situation. My
opinion is that the most common overcurrent situation is a short
circuit. This is what circuit breakers do. If I didn't think a circuit
breaker was acceptable for this I wouldn't use them anywhere else either
as I'd have to replace the breaker every time it tripped and fuses are
cheaper in that case. Mine still seem to do the job after several dozen
OVM trips fed by modern AGM batteries...
Ken
>Unsubstantiated allegations? The circuit breaker is not rated for the
>current. It is the designer's responsibilty to make sure the design meets
>the requirement. To use the term "unsubstantiated allegations" seems very
>strange when discussing merely technical performance. The "allegations" are
>very much substantiated. The circuit breaker won't do the job. Look it up.
>
>
________________________________________________________________________________
| From: | Charlie England <ceengland(at)bellsouth.net> |
| Subject: | Re: crowbar method |
Kevin Horton wrote:
>
>
>
>>
>>
>>
>>
>>
>>
>>>I'll take a stab at this. Crowbar just means that when the
>>>Overvoltage
>>>
>>>
>>>
>>trips the SCR, the SCR shorts out the power.( Kind of like throwing a
>>crowbar across the battery to short things out.) That immediately
>>starts
>>dropping the voltage (a good thing) and the current flow through
>>the CB
>>trips the CB to permanently shutdown the alternator.
>>
>>Correct. However, the circuit breaker is not rated for this abuse.
>>Nor is
>>adding a small resistor to bring the currents down simple (see earlier
>>posts), since pulse resistors are a special breed.
>>
>>
>>
>>
>>>The SCR causes a significant momentary current flow or pulse from the
>>>
>>>
>>>
>>battery through the CB. There have been some (unsubstantiated in my
>>opinion) allegations that it could be harmful in vague ways.
>>
>>Unsubstantiated allegations? The circuit breaker is not rated for the
>>current. It is the designer's responsibilty to make sure the design
>>meets
>>the requirement. To use the term "unsubstantiated allegations"
>>seems very
>>strange when discussing merely technical performance. The
>>"allegations" are
>>very much substantiated. The circuit breaker won't do the job. Look
>>it up.
>>
>>
>>
>>
>
>The CB specs provide an envelope of conditions under which the CB
>should perform as advertised, repeatedly - i.e. it will trip within a
>certain time, at a certain tolerance to the advertised trip current.
>But the spec sheet doesn't say what will happen if it is operated at
>other conditions. It doesn't say how its performance will be
>affected. So how do we know it won't do the job? Is there evidence
>that it won't do the job, or is the statement "the circuit breaker
>won't do the job" simply an unsubstantiated allegation?
>
>I'd love to see the test results that show the CB in a crowbar OVP
>won't do the job. Bob has described tests he has down that show the
>CB will do the job, and the only complaints from the field seem to be
>some installations that are prone to nuisance trips. The later
>variants of the design are reputed to be less prone to nuisance trips.
>
>If we operate the CB outside its rated current repeatedly, this could
>possibly affect the current at which the CB will open. But, the
>exact value at which it opens isn't important in this application.
>Normally there is very little current through the CB. If there is an
>overvoltage, and the OVP trips, there will be a very large current
>though the CB. We only need the CB to differentiate between a very
>small current, and a very large one. It doesn't matter exactly what
>its trip point is.
>
>Kevin Horton RV-8 (finishing kit)
>Ottawa, Canada
>http://www.kilohotel.com/rv8
>
Others have posted on this topic who can speak with much more authority
than I, but it seems to me that saying that a breaker isn't designed to
open a circuit when there's a short flies in the face of all logic. It
seems to me, that's why it's there in the 1st place. It isn't there to
protect some device from moderate over-current; the mfgr of the device
has the responsibility to do that. The breaker is there to protect
downstream wire from melting/burning in the case of gross over-current
conditions (shorts). Would anyone maintain that we should go find some
high tech alternative for our house breakers because they aren't
designed to open the circuit if someone shorts out a circuit by
accidentally cutting into a lamp cord with a pair of scissors?
Aren't the crowbar circuits being discussed designed to short across the
supply to the field winding of the alternator? Following the 'not
designed for the job' argument, is another solution needed for a
traditional alternator field breaker in its traditional role considering
that a wire between the breaker & the alternator might inadvertently rub
against the chassis somewhere & short to ground? If the breaker is
unsuitable for a crowbar circuit, it is just as unsuitable to open the
same circuit if there is an insulation failure on the wire & it touches
a grounded portion of the airframe.
I haven't seen anyone say that repeated trips of the breaker due to hard
shorts is a good thing. Most breakers aren't designed for high cycling
counts; they are just there to protect against the (hopefully) rare
catastrophic event. If there is repeated cycling, the problem needs to
be fixed, not designed around with some high tech circuit. If I have
hundreds of trip events of a circuit breaker & it eventually fails to
protect the circuit, I'm probably getting what I deserve. On the other
hand, if it won't protect against at least a few catastrophic short
events over the life of the a/c, I've wasted my money on that
high-dollar breaker.
Charlie
no technical degrees after my name but a career in consumer & industrial
electronics maintenance behind me
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: crowbar method |
>This is where we disagree I guess Eric.
Circuit breakers are used to interupt an overcurrent situation. My
opinion is that the most common overcurrent situation is a short
circuit. This is what circuit breakers do. If I didn't think a circuit
breaker was acceptable for this I wouldn't use them anywhere else either
as I'd have to replace the breaker every time it tripped and fuses are
cheaper in that case. Mine still seem to do the job after several dozen
OVM trips fed by modern AGM batteries...Ken
Nothing is as simple as it seems. The manufacturers publish specificatons on
what their products are rated to do. But even in the most simple situations
it is just plain wrong to think you can stretch the limits. Maybe you can
get away with it once or twice--but as a design, it is always a mistake to
think you know better than the manufacturer. After all the manufacture would
LOVE to find out their parts work above their design--that their Buna-N
Orings operate at 40 degrees F. It's money in the bank for them. And even
then you risk the manufacturer's right to modify the device while remaining
inside her specifications. This is a common engineer's trap. There are
ALWAYS free-floating specs that the manufacurer won't guarantee. In this
case, the tests haven't been done and the parts aren't specified to do the
job.
If a circuit breaker is called upon to interrupt a current above its
designed rating (volts, amps, temp, time, etc.), the contacts can weld, the
mechanism can blow apart, the materials can change properties, the spacings
may be inadequate, the repeat characteristics can change. Furthermore it is
up to the designer to show the design is right. Even in the case where a new
design requires testing--the tests have to be done and documented.
These alligators....are substantial.
>The CB specs provide an envelope of conditions under which the CB
should perform as advertised, repeatedly - i.e. it will trip within a
certain time, at a certain tolerance to the advertised trip current.
But the spec sheet doesn't say what will happen if it is operated at
other conditions. It doesn't say how its performance will be
affected. So how do we know it won't do the job? Is there evidence
that it won't do the job, or is the statement "the circuit breaker
won't do the job" simply an unsubstantiated allegation?
"So how do we know it won't do the job?" We don't. But it's a silly
question to ask. Think about it. Okay, maybe it WILL do the job. Maybe.
>I'd love to see the test results that show the CB in a crowbar OVP
won't do the job. Bob has described tests he has down that show the
CB will do the job, and the only complaints from the field seem to be
some installations that are prone to nuisance trips. The later
variants of the design are reputed to be less prone to nuisance trips.
Paul Messinger has data on the crowbar OVP showing adequate current to trash
the CB. ....but he also has a burr under his saddle. And a stone in his
boot. But he makes the good point and I agree, that it is not up to anybody
else to show the crowbar/CB is suited for the job. That's not how science
works. So don't be too annoyed that he doesn't want to finish the report.
>If we operate the CB outside its rated current repeatedly, this could
possibly affect the current at which the CB will open. But, the
exact value at which it opens isn't important in this application.
Normally there is very little current through the CB. If there is an
overvoltage, and the OVP trips, there will be a very large current
though the CB. We only need the CB to differentiate between a very
small current, and a very large one. It doesn't matter exactly what
its trip point is. Kevin Horton
Kevin...Maybe, but what if you designed this into a real airplane?
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
(508) 764-2072
"The man who carries a cat by the tail learns something that can be learned
in no other way."
- Mark Twain
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: crowbar method |
ceengland(at)bellsouth.net
>>Others have posted on this topic who can speak with much more authority
than I, but it seems to me that saying that a breaker isn't designed to
open a circuit when there's a short flies in the face of all logic. It
seems to me, that's why it's there in the 1st place. It isn't there to
protect some device from moderate over-current; the mfgr of the device
has the responsibility to do that. The breaker is there to protect
downstream wire from melting/burning in the case of gross over-current
conditions (shorts). Would anyone maintain that we should go find some
high tech alternative for our house breakers because they aren't
designed to open the circuit if someone shorts out a circuit by
accidentally cutting into a lamp cord with a pair of scissors?
Charlie--A short circuit can produce high currents limited only by the
circuit impedance. This impedance can be very very low. That's the problem.
At 14.5 volts, a short of 0.001 ohms is 14500 amps. Of course your 5A
circuit breaker would emit gamma rays at this current. (I'm not kidding).
Lucky for us, in the real world the circuit breaker will probably not have
to handle such a current, but the crowbar/CB combination WILL suffer damage
as currently designed. Bob and Paul argued the exact current---but in
summary it depends on where the battery is and what the battery is.
>>Aren't the crowbar circuits being discussed designed to short across the
supply to the field winding of the alternator? Following the 'not
designed for the job' argument, is another solution needed for a
traditional alternator field breaker in its traditional role considering
that a wire between the breaker & the alternator might inadvertently rub
against the chassis somewhere & short to ground? If the breaker is
unsuitable for a crowbar circuit, it is just as unsuitable to open the
same circuit if there is an insulation failure on the wire & it touches
a grounded portion of the airframe.
Negatory, the normal length of wire between the CB and the alternator or
regulator will reduce the current by resistance and inductance a little bit,
and that is enough to allow the 5A breaker to work as designed. In the case
of the OVP/CB, this grounding can be a very large current. (but it depends
on layout....). Also real short circuits are rarely "slammed down hard to
ground".
>>I haven't seen anyone say that repeated trips of the breaker due to hard
shorts is a good thing. Most breakers aren't designed for high cycling
counts; they are just there to protect against the (hopefully) rare
catastrophic event. If there is repeated cycling, the problem needs to
be fixed, not designed around with some high tech circuit. If I have
hundreds of trip events of a circuit breaker & it eventually fails to
protect the circuit, I'm probably getting what I deserve. On the other
hand, if it won't protect against at least a few catastrophic short
events over the life of the a/c, I've wasted my money on that
high-dollar breaker.
Correcto. And since breakers don't have "History Recorders" on them, it's
hard to know. Even the first trip can be a problem operated outside of the
manufacturers specs. Maybe you'll get lucky. Or maybe you'll be in
Huatabampo Mexico (a very nice town, but not many replacement parts).
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
(508) 764-2072
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> again! |
| Subject: | Re: Paul M. has risen from the dead |
again!
>Geez, I see that "Pope Paul M." is once again pontificating. Lord! why
>can't he be excommunicated?
>
>Peter Van Caulart
Folks, I really would like to focus on simple-ideas, repeatable
experiments and to encourage any honorable action that helps
move our craft forward. This kind of response adds nothing
useful to anyone's experience.
I've had a ton of flack from a few who want this discussion
"moved off list" or "burried" etc. etc.
I've encourage folks who are upset by the discussion to
please not read it. There's another group of folks who need
the list deal with "where to I buy" and "how do I hook up"
kinds of questions. For those folks too, I would encourage
you to use the delete key.
For those who are interested in learning how logic, simple-ideas,
and cooperative design review can filter the BS and suggest
ways to make your airplane work better, cost less and be
easier to repair, then keep a finger on the pulse of things.
But if any part of it upsets you for any reason other a
proffering of bad science or a demonstration of bad behavior,
then please don't read it.
Life is too short and your airplane project is taking
too long, you don't need more aggravation. Don't for
a moment think that I'm one bit tense over these discussions.
When I'm tense, I'll make it known and describe the exact
reason why.
Unless you have some specific questions and/or contribution
to the discussions, please don't throw more cabbages and
tomatoes. It doesn't help.
Thanks!
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: I've got a secret |
>
>If you think that's hateful, you must be new to the internet.
>
>Are you capable of summing up this amazingly useless, endless thread
>in one paragraph? Like
>
>The problem is X
>It can occur when using equipment Y, under the following conditions -
>If you use equipment Z instead, it won't happen.
>
>I appreciate the free ice cream that Bob delivers here. It's not
>always my favorite flavor, but it's still free. (That's a metaphor, BTW)
Gentlemen, please. If you're not a participant in seeking solutions,
please don't be part of an unrelated problem. Nobody is guaranteed
an insult free existence . . . but keep in mind that one can only
be insulted if you give someone permission to do it!
Bob . . .
________________________________________________________________________________
| From: | Charlie England <ceengland(at)bellsouth.net> |
| Subject: | Re: crowbar method |
Eric M. Jones wrote:
>
>ceengland(at)bellsouth.net
>
>
>
>>>Others have posted on this topic who can speak with much more authority
>>>
>>>
>than I, but it seems to me that saying that a breaker isn't designed to
>open a circuit when there's a short flies in the face of all logic. It
>seems to me, that's why it's there in the 1st place. It isn't there to
>protect some device from moderate over-current; the mfgr of the device
>has the responsibility to do that. The breaker is there to protect
>downstream wire from melting/burning in the case of gross over-current
>conditions (shorts). Would anyone maintain that we should go find some
>high tech alternative for our house breakers because they aren't
>designed to open the circuit if someone shorts out a circuit by
>accidentally cutting into a lamp cord with a pair of scissors?
>
>Charlie--A short circuit can produce high currents limited only by the
>circuit impedance. This impedance can be very very low. That's the problem.
>At 14.5 volts, a short of 0.001 ohms is 14500 amps. Of course your 5A
>circuit breaker would emit gamma rays at this current. (I'm not kidding).
>Lucky for us, in the real world the circuit breaker will probably not have
>to handle such a current, but the crowbar/CB combination WILL suffer damage
>as currently designed. Bob and Paul argued the exact current---but in
>summary it depends on where the battery is and what the battery is.
>
>
>
>>>Aren't the crowbar circuits being discussed designed to short across the
>>>
>>>
>supply to the field winding of the alternator? Following the 'not
>designed for the job' argument, is another solution needed for a
>traditional alternator field breaker in its traditional role considering
>that a wire between the breaker & the alternator might inadvertently rub
>against the chassis somewhere & short to ground? If the breaker is
>unsuitable for a crowbar circuit, it is just as unsuitable to open the
>same circuit if there is an insulation failure on the wire & it touches
>a grounded portion of the airframe.
>
>Negatory, the normal length of wire between the CB and the alternator or
>regulator will reduce the current by resistance and inductance a little bit,
>and that is enough to allow the 5A breaker to work as designed. In the case
>of the OVP/CB, this grounding can be a very large current. (but it depends
>on layout....). Also real short circuits are rarely "slammed down hard to
>ground".
>
>
>
>>>I haven't seen anyone say that repeated trips of the breaker due to hard
>>>
>>>
>shorts is a good thing. Most breakers aren't designed for high cycling
>counts; they are just there to protect against the (hopefully) rare
>catastrophic event. If there is repeated cycling, the problem needs to
>be fixed, not designed around with some high tech circuit. If I have
>hundreds of trip events of a circuit breaker & it eventually fails to
>protect the circuit, I'm probably getting what I deserve. On the other
>hand, if it won't protect against at least a few catastrophic short
>events over the life of the a/c, I've wasted my money on that
>high-dollar breaker.
>
>Correcto. And since breakers don't have "History Recorders" on them, it's
>hard to know. Even the first trip can be a problem operated outside of the
>manufacturers specs. Maybe you'll get lucky. Or maybe you'll be in
>Huatabampo Mexico (a very nice town, but not many replacement parts).
>
>Regards,
>Eric M. Jones
>www.PerihelionDesign.com
>113 Brentwood Drive
>Southbridge MA 01550-2705
>(508) 764-2072
>
But Eric, if the crowbar is after the alternator field breaker, all the
wire between the battery & the breaker & load mentioned in your argument
is still there (or not there). If the breaker is in danger from the
crowbar, it follows that it is in danger from an inadvertent short
circuit. Yet alternator field circuit breakers seem to have survived as
a design since the dawn of alternators in a/c.
(If I could be convinced that this 'slam down' technique really is
dangerous, why do I need dozens of extra components to solve the
problem? Why not just use one of those gadgets with inverse temperature
coefficient used to soft start incandescent lamps in series with the crowbar?)
Charlie
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Diode orientation |
>
>Bob, et al,
>
>My Navaid installation manual recommends a diode between the Navaid pin
>7 and the Comm PTT circuit. The Navaid schematic shows a black and white
>diode with a large white area and a small black stipe on one end. The
>white area is oriented toward the Comm unit and the black stripe
>oriented toward the PTT circuit. However, the diode I received from B&C
>is mostly black with a small grey stripe at one end.
>
>Can I assume that the large black end of the diode equates to the large
>white end on the Navaid schematic?
The descriptions you're making for the parts and wiring
diagram are don't give us a clear image of the instructions.
Most wire lead diodes have a "band" on one end and the color
of the band is insignificant. It will be some color that
contrasts with the body color of the diode itself.
The banded end corresponds to the "cathode". In a diode's
schematic, the "bar" touched by the arrowhead is the
cathode while the arrowhead itself is the anode. Electrons
flow through a diode in opposition to direction of arrow.
See:
http://www.aeroelectric.com/Pictures/Diode_Wiring_2.jpg
Some folks are confused when they see diodes used for two
different tasks like "steering" as shown in -A- and -B-
and spike clipping as shown in -C- and -D-.
Do you have a real schematic of the wiring were the
bar and arrowhead are seen in the classic diode symbol
. . . or is it a comic book wiring diagram that shows
only pictures? Sounds like you're working with the latter.
In this case, go by which end has a band on it irrespective
of color. Do they say what this diode is supposed to do?
I'm mystified by the need hook any part of your comm transceiver
to the autopilot.
Bob . . .
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: crowbar method |
Eric M. Jones wrote:
>
>
>ceengland(at)bellsouth.net
>
>
>>>Others have posted on this topic who can speak with much more authority
>>>
>>>
>than I, but it seems to me that saying that a breaker isn't designed to
>open a circuit when there's a short flies in the face of all logic. It
>seems to me, that's why it's there in the 1st place. It isn't there to
>protect some device from moderate over-current; the mfgr of the device
>has the responsibility to do that. The breaker is there to protect
>downstream wire from melting/burning in the case of gross over-current
>conditions (shorts). Would anyone maintain that we should go find some
>high tech alternative for our house breakers because they aren't
>designed to open the circuit if someone shorts out a circuit by
>accidentally cutting into a lamp cord with a pair of scissors?
>
>Charlie--A short circuit can produce high currents limited only by the
>circuit impedance. This impedance can be very very low. That's the problem.
>At 14.5 volts, a short of 0.001 ohms is 14500 amps. Of course your 5A
>circuit breaker would emit gamma rays at this current. (I'm not kidding).
>Lucky for us, in the real world the circuit breaker will probably not have
>to handle such a current, but the crowbar/CB combination WILL suffer damage
>as currently designed. Bob and Paul argued the exact current---but in
>summary it depends on where the battery is and what the battery is.
>
>
>>>Aren't the crowbar circuits being discussed designed to short across the
>>>
>>>
>supply to the field winding of the alternator? Following the 'not
>designed for the job' argument, is another solution needed for a
>traditional alternator field breaker in its traditional role considering
>that a wire between the breaker & the alternator might inadvertently rub
>against the chassis somewhere & short to ground? If the breaker is
>unsuitable for a crowbar circuit, it is just as unsuitable to open the
>same circuit if there is an insulation failure on the wire & it touches
>a grounded portion of the airframe.
>
>Negatory, the normal length of wire between the CB and the alternator or
>regulator will reduce the current by resistance and inductance a little
>bit,
>and that is enough to allow the 5A breaker to work as designed. In the case
>of the OVP/CB, this grounding can be a very large current. (but it depends
>on layout....). Also real short circuits are rarely "slammed down hard to
>ground".
>
>
>>>I haven't seen anyone say that repeated trips of the breaker due to hard
>>>
>>>
>shorts is a good thing. Most breakers aren't designed for high cycling
>counts; they are just there to protect against the (hopefully) rare
>catastrophic event. If there is repeated cycling, the problem needs to
>be fixed, not designed around with some high tech circuit. If I have
>hundreds of trip events of a circuit breaker & it eventually fails to
>protect the circuit, I'm probably getting what I deserve. On the other
>hand, if it won't protect against at least a few catastrophic short
>events over the life of the a/c, I've wasted my money on that
>high-dollar breaker.
>
>Correcto. And since breakers don't have "History Recorders" on them, it's
>hard to know. Even the first trip can be a problem operated outside of the
>manufacturers specs. Maybe you'll get lucky. Or maybe you'll be in
>Huatabampo Mexico (a very nice town, but not many replacement parts).
>
>But Eric, if the crowbar is after the alternator field breaker, all the
>wire between the battery & the breaker & >load mentioned in your argument
>is still there (or not there). If the breaker is in danger from the
>crowbar, it >follows that it is in danger from an inadvertent short
>circuit. Yet alternator field circuit breakers seem to have >survived as a
>design since the dawn of alternators in a/c.(If I could be convinced that
>this 'slam down' technique >really is dangerous, why do I need dozens of
>extra components to solve the problem? Why not just use one of >those
>gadgets with inverse temperature coefficient used to soft start
>incandescent lamps (sorry; I forget the >name of the device> in series with
>the crowbar?)Charlie
Charlie, I have decided that this whole issue would be easier if I released
the design of my Linear OVM. (email me if you want the PDF). A kit-built
version is still unlikely but perhaps Bob or somone will make something
similar.
The circuit breaker current is limited by the impedance (the combined
resistance and inductance and other contributions to reducing the current).
This is highly dependent on wiring layout.
>>why do I need dozens of extra components to solve the problem?..........
Which parts would you like me to remove (as Mozart might have said)? And why
is my income tax form so complicated?
The devil is in the details. Yes, there are other ways to do this. A
thermistor might be one way. To lower the peak current throught the CB, even
a loop of wire will help.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
(508) 764-2072
"Everything you've learned in school as "obvious" becomes
less and less obvious as you begin to study the universe.
For example, there are no solids in the universe. There's
not even a suggestion of a solid. There are no absolute con-
tinuums. There are no surfaces. There are no straight lines."
- R. Buckminster Fuller
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: crowbar method |
>
>
>But Eric, if the crowbar is after the alternator field breaker, all the
>wire between the battery & the breaker & load mentioned in your argument
>is still there (or not there). If the breaker is in danger from the
>crowbar, it follows that it is in danger from an inadvertent short
>circuit. Yet alternator field circuit breakers seem to have survived as
>a design since the dawn of alternators in a/c.
>
>(If I could be convinced that this 'slam down' technique really is
>dangerous, why do I need dozens of extra components to solve the
>problem? Why not just use one of those gadgets with inverse temperature
>coefficient used to soft start incandescent lamps name of the device> in series with the crowbar?)
The trade name for these devices is Polyswitch. These are
the same devices that EXPBus and Greg Richter have embraced
as their circuit protectors of choice. See:
http://www.circuitprotection.com/polyswitch.asp
These are simply replacements for breakers and fuses and have
no ability to sense and react to an ov condition.
There were two major drivers in design goals for the development
of the crowbar system 25 years ago. (1) replace expensive/troublesome
relays with a solid state device and (2) reduce if not eliminate all
increase of power pathway resistance between the bus and a
voltage regulator.
Popular voltage regulators of the time did not have separate
bus sense and field power leads. This opens the door for voltage
regulator instability (bouncing ammeter syndrome) as aging
of components between regulator and bus increase the series
resistance to the point where the regulator becomes unstable.
(I'm working on an article that addresses this phenomenon
in response to an AeroElectric List posting concerning
a bouncing ammeter).
Many articles have been written about the cure for bouncing
ammeter syndrome wherein the writer speaks to replacement of
some component as being the cure . . . when in fact, resistance
of ALL components in the power pathway contribute to the effect
and replacing one of them simple reduces TOTAL resistance to
some value below the threshold of instability.
In a nutshell, the article I'm working on suggests that 30+
year old airplanes that present with the bouncing ammeter
syndrome will benefit from complete replacement of all ohmic
(pressure joints) in wiring between the bus and the regulator.
Total refurbishment will put the airplane back into a factory
new condition for this pathway offers a high probability
of 30 more years of stable operation. Replacing but one of
several contributors to the problem will 'cure' the
instability for a relatively short time.
Crowbar ov protection was an ideal solution to part of this
problem because it inserted NO series resistance into the pathway
it controlled. Further, its parts count was quite low and
the design problems with system integration for controlling
nuisance trips were achievable.
Folks have suggested there was no good reason for doing
ov protection this way . . . but had they read any of the
history of the philosophy and understood all the design goals
then perhaps the reasoning would have been clear.
Unusual? Yes, but it was not considered and adopted as
a passing fad. There were reasons traded off with system
integration issues to be solved. And except for instances
where individuals with agendas inserted themselves into
the relationship between honorable suppliers and customers
who were entitled their money's worth, the concept has
performed well in the field.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: crowbar method |
>
>Charlie--A short circuit can produce high currents limited only by the
>circuit impedance. This impedance can be very very low. That's the problem.
>At 14.5 volts, a short of 0.001 ohms is 14500 amps. Of course your 5A
>circuit breaker would emit gamma rays at this current. (I'm not kidding).
>Lucky for us, in the real world the circuit breaker will probably not have
>to handle such a current, but the crowbar/CB combination WILL suffer damage
>as currently designed. Bob and Paul argued the exact current---but in
>summary it depends on where the battery is and what the battery is.
The battery is but ONE of many contributors to source impedance.
Judicious use of crowbar ov protection demands that one not
design for worst case fault currents during the crowbar event
and by inference (if nothing else) our wiring diagrams suggest
far less than worse case installations.
Nowhere do we suggest that the system should be assembled with
a .003 ohm circuit breaker and zero lead lengths between the
bus and the crowbar device. So the hypothesized 700, 500
and/or 14,500 amp current flows simply never happen. The
biggest 24 volt batteries we install at RAC will only dump
about 3000 amps with a dead short on their terminals . . .
so be wary of writers who toss around really big numbers
to impress . . . they don't happen in real life.
Which leaves us debating whether one should design the system
to avoid damaging a breaker (which has yet to be demonstrated)
during what should be a very rare event or should we concentrate
on getting a failed alternator disconnected first and worry
about circuit breaker life later?
By the way, a runaway alternator disconnected from the bus
by opening a b-lead contactor will continue to run to its
own destruction. So, if the ovp system has to operate for
a real ov event in an automotive alternator installation,
overstress to the circuit breaker is going to be a trivial
concern.
I'll suggest that one not even consider the battery's
source impedance in controlling crowbar fault current.
ASSUME zero source impedance. Now, build enough loop
resistance into the system by simply following the
installation instructions and you'll be just fine.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | The fatwire ground blues . . . |
>Comments/Questions: I am implementing your dual alt/batt/buss system on my
>GA-III. I fried a ground wire(lots of smoke)due to a loose battery ground
>connection while cranking the starter! The fried wire went to the fuel
>flow sensor mounted on the engine block. The starter return current tried
>to use the smaller wire due to a loose battery ground connector to the
>Alt-Battery. Should the sensors(Vision Micro) mounted on the engine block
>(fuel flow, fuel press, oil temp, oil press) have ground wires that
>connect to the engine block? These wires can be potential return paths for
>heavy starter current with a loose (-) battery connection.
I'm not sure I visualize exactly what happened
here. My recommendation is that all high current grounds
like crankcase and battery(-) leads come to a firewall
ground stud as illustrated in Chapter 5 of the 'Connection.
Your experience is not uncommon. Folks on the airport we
owned had two wire-smoking incidents similar to yours
for the 6 months we had the business!
Careful adherence to the ground architectures described
in Chapter 5 will reduce noise and possibly prevent a
recurrence . . . IF you are mindful of doors that open
every time you unhook a 'fat' wire and being careful that
they're all put back before you attempt to operate the
system . . . ESPECIALLY crank the engine.
Bob . . .
________________________________________________________________________________
| From: | "Jim Ivey" <jim(at)jimivey.com> |
| Subject: | RE: [luscombe-silvaire] Need help with Apollo GPS |
Back on the list. I was bumped while in OSH for some reason. Catching up
and saw Bill's request on the Apollo unit. So if you're not interested
don't bother reading the "too much information" below:
Bill:
The 360 GPS is updated with a DOS-based transfer program provided on the
program diskette. I have both. The program is very, very basic and merely
loads the new dataset into the unit. It is not Windows and has not been
updated since about 1996. Works fine. You are, however, offered the option
of saving existing user waypoints first to restore them after a new database
is loaded. The software does not show any of the display on the unit
itself. When the GPS was initially purchased it came with a computer
interface connector to be located on the panel somewhere so updates would
not require the removal of the unit. If your unit is used it may not have
this remote serial connector. Also, many avionics shops skipped this step.
If you don't have that then you may have to remove the unit in order to
update. Pin-Out diagrams are included in the installation manual. When you
order a database update from Garmin AT it will arrive on a second diskette
the program will load.
However, the unit does output about 3 different versions of serial data. I
send moving-map serial data to my EDM800 engine monitor and it uses that
information in fuel calculations. You can also use this output to run a
third-party software such as Anwywhere Map, AirGator, Mountainscope or even
the likes of an Aspen Avionics AT300 multifunction display. Check with the
software manufacturer. Use the pin-out diagram to make your own cable or
hire your local avionics tech to do it for you (be sure they use shielded
cable for serial cable and ground shield at source end). The Apollo (UPSAT,
GarminAT?) kit cables are strictly set up for database updates and do not
contain the wires for data output for other devices.
In summary, if you need to update the database use the diskette and cable as
described. To use the unit as a GPS source for a laptop you will need
somebody else's software and a custom cable. At that point you may like to
buy a stand-alone GPS engine like a Garmin 35 or Traker Blue (if you use
Bluetooth and don't want wires all over the cockpit).
Call the Garmin AT guys in Salem, Oregon and talk to them at 1-800-525-6726
ext.3991. They are very knowledgeable and nice and will talk to you about
your unit. They can also tell whether it has been updated to the advanced
display (easy to read) or not just by the serial number. It was a sobering
day for me when Garmin bought UPSAT. You'd be lucky if the unit is
supported beyond another year or so.
I can send a copy of the software diskette but don't have an extra data
cable for you. As for the database it has encryption so it can only be
loaded on one serialized unit ... no sharing possible.
Jim Ivey
P.S. Despite the 360 unit's slow frequency response to command inputs, most
knowledgeable technicians will tell you that the GPS 360 (or 920 handheld)
had the most reliable and accurate GPS engine ever produced. Antiquated in
GPS years, but bulletproof. I own 2 and would like to have 3. If you buy
one on eBay or Trade-A-Plane get the serial no. before bidding and call the
factory to see if it has all the updates and what the repair history is.
-----Original Message-----
From: luscombe-silvaire(at)yahoogroups.com
[mailto:luscombe-silvaire(at)yahoogroups.com] On Behalf Of WRBYARS(at)aol.com
Subject: [luscombe-silvaire] Need help with Apollo GPS
Greetings to All,
I'm in a bit of a dilemma with my Apollo 360 GPS Moving Map Unit, (round
unit installed in the panel) which was installed with the latest data in
1997.
This unit can be upgraded by using a lap top computer with an "upgrade card"
in the floppy drive, connected to the GPS with a serial cable, according to
the Installation Guide.
Does anyone have a recent "up grade card", and cable to connect up with that
they would sell, loan, rent, whatever?
Here is the info that the "Guide" gives on these items.
PC Interface Kit (564-0052), which includes a program diskette (31/2"),the
data cable (500-0263), and a reference guide.
Data Cable (500-0263), a 25 pin on the GPS end, to a 9 pin dsub COM port on
the PC.
Also does anyone know if the GPS unit, when hooked up to a color lap top,
will display the same info on the lap top that is on the "Mother" unit on
the panel, and although the original unit display is in black & white, would
the lap top display the info in color? If it will, then the "co-pilot"/
passenger could have a larger, in color, view, to assist the pilot with.
Sorry this is so long, however I know there is a lot of Very Knowledgeable
folks out there on the list, and I very much need your help.
Thanks
Bill
_____
=09
* Visit your group "luscombe-silvaire
<http://groups.yahoo.com/group/luscombe-silvaire> " on the web.
* To unsubscribe from this group, send an email to:
luscombe-silvaire-unsubscribe(at)yahoogroups.com
<http://docs.yahoo.com/info/terms/> .
_____
________________________________________________________________________________
| From: | "Ronald J. Parigoris" <rparigor(at)SUFFOLK.LIB.NY.US> |
| Subject: | Bad Alternator ground on V-Tail! |
I was working on Europa build over weekend, and a guy with a V-Tail across way
was working
on his V-Tail. No alternator output.
I will note I helped him change it about 6 months ago, and he was having a hard
job
fitting it in place. It ended up whoever rebuilt it, or made it got paint on the
flange, I
helped him cover up everything, and did a shoeshine with a cut piece of 1 x 42
belt
sander.
OK till now. No charge. he went after all connectors, and it seemed to work. then
after
fuel it quit. he started to show me and it worked again!
There was play between the 2 halves of the alternator! It was safety wired, but
I suspect
whoever did the painting got carried away, and got it on the mating surfaces inside
the
alternator. Once the paint wore away due to vibration and heat, things got loose.
The hold
down screws were heavily corroded as they were making that intermittent connection
between
the 2 halves sometimes, and the stacked pieces of metal between the 2 halves were
pretty
corroded as well.
The screws looked 50 years old, when I am pretty certain they were new 6 months
ago.
Ron Parigoris
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Bad Alternator ground on V-Tail! |
>
>
>I was working on Europa build over weekend, and a guy with a V-Tail across
>way was working
>on his V-Tail. No alternator output.
>
>I will note I helped him change it about 6 months ago, and he was having a
>hard job
>fitting it in place. It ended up whoever rebuilt it, or made it got paint
>on the flange, I
>helped him cover up everything, and did a shoeshine with a cut piece of 1
>x 42 belt
>sander.
>
>OK till now. No charge. he went after all connectors, and it seemed to
>work. then after
>fuel it quit. he started to show me and it worked again!
>
>There was play between the 2 halves of the alternator! It was safety
>wired, but I suspect
>whoever did the painting got carried away, and got it on the mating
>surfaces inside the
>alternator. Once the paint wore away due to vibration and heat, things got
>loose. The hold
>down screws were heavily corroded as they were making that intermittent
>connection between
>the 2 halves sometimes, and the stacked pieces of metal between the 2
>halves were pretty
>corroded as well.
>
>The screws looked 50 years old, when I am pretty certain they were new 6
>months ago.
Good detective work. Thanks for giving us the story.
They say the devil is in the details . . . and I can
attest to that. Worked a problem a few years ago on a
pitch trim system where many $millions$ in warranty and
untold cost in customer dissatisfaction was rooted on
a material change of brake material from asbestos (EPA
strikes again!) to cork.
Bob . . .
________________________________________________________________________________
| From: | Charlie England <ceengland(at)bellsouth.net> |
| Subject: | Re: crowbar method |
Robert L. Nuckolls, III wrote:
>
>
>
>
>>But Eric, if the crowbar is after the alternator field breaker, all the
>>wire between the battery & the breaker & load mentioned in your argument
>>is still there (or not there). If the breaker is in danger from the
>>crowbar, it follows that it is in danger from an inadvertent short
>>circuit. Yet alternator field circuit breakers seem to have survived as
>>a design since the dawn of alternators in a/c.
>>
>>(If I could be convinced that this 'slam down' technique really is
>>dangerous, why do I need dozens of extra components to solve the
>>problem? Why not just use one of those gadgets with inverse temperature
>>coefficient used to soft start incandescent lamps >name of the device> in series with the crowbar?)
>>
>>
>
> The trade name for these devices is Polyswitch. These are
> the same devices that EXPBus and Greg Richter have embraced
> as their circuit protectors of choice. See:
>
>http://www.circuitprotection.com/polyswitch.asp
>
> These are simply replacements for breakers and fuses and have
> no ability to sense and react to an ov condition.
>
>
> <> snip
> <>
> Bob . . .
Actually, I was talking about retaining the standard crowbar circuit &
breaker & just adding a single component (the gadget that is
occasionally used to avoid large inrush current in incandescent lights)
in series with the crowbar contacts that would force a ramp up of
current through the trip threshold of the breaker instead of the dreaded
'slam dunk' overcurrent Eric's worried about. I only mentioned it to
show that some elaborate multicomponent top secret circuit isn't needed.
The primary point of my post was that if a breaker can handle rare 'slam
dunk' overcurrents due to faulty wiring, it can also handle the crowbar
circuit. I see no need for any additional components.
Charlie
________________________________________________________________________________
| From: | "Hinde, Frank George (Corvallis)" <frank.hinde(at)hp.com> |
With my all electric airplane (Lycoming with Emags and elctric fuel
pumps only) I have found that by using a simple com radio (backup to GNS
430) in receive mode and transponder I can get my total current draw
down to a shade under 8 amps which fits nicely into the SD-8 backup.
Using Bob's 3 buss design I can easily save my battery reserve to do the
approach/run the lights for when I land.
The above assumes I run only one fuel pump (I have one in each wing
root) and one Emag.
Having a Pmag on a dual alternator systems seems like two layers of
redundancy to me...Do we agree?
Thanks
Frank
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: crowbar method |
>
>
>Actually, I was talking about retaining the standard crowbar circuit &
>breaker & just adding a single component (the gadget that is
>occasionally used to avoid large inrush current in incandescent lights)
>in series with the crowbar contacts that would force a ramp up of
>current through the trip threshold of the breaker instead of the dreaded
>'slam dunk' overcurrent Eric's worried about. I only mentioned it to
>show that some elaborate multicomponent top secret circuit isn't needed.
>
>The primary point of my post was that if a breaker can handle rare 'slam
>dunk' overcurrents due to faulty wiring, it can also handle the crowbar
>circuit. I see no need for any additional components.
>
>Charlie
Aha! Understand. It's been proposed that adding a resistor
in series with the crowbar module would mitigate the
crowbar fault current . . . which is correct. However,
It runs contrary to some original design goals.
One of the neat things about the crowbar technique is that
supply voltage to the alternator regulator is clamped off at
about 2 volts immediately after the SCR triggers. This means
that the ov condition is cooling off even before the
breaker opens. Adding this resistor would increase parts
count, adds a mechanical issue for packaging (see photos)
http://www.aeroelectric.com/Pictures/OVM-14_A.jpg
http://www.aeroelectric.com/Pictures/OVM-14_B.jpg
http://www.aeroelectric.com/Pictures/OVM-14_B.jpg
Finally, added resistance would have increased excitation
voltage available to the regulator while the breaker was
deciding to trip . . . and it takes longer to decide
due to reduced fault current. This would have reduced
effectiveness of the system while offering no benefits
I could demonstrate.
Adding the mitigation resistance any place else would
have driven up the bus-to-regulator pathway resistance.
This was root cause of numerous regulator instability
problems.
Your supposition is correct. The breaker in B&C's test
stand for their regulators has experienced thousands
of crowbar events (150 A or so in 14v mode, 300A in
24v mode) and last time I checked with Tim, the breaker
in place today was the one I installed there about
15 years ago. Granted, it's a high-end product equal
to the miniature breakers used in the majority of our
aircraft at RAC.
As I pointed out in an earlier post, this class of
breaker is routinely qualified in test situations where
potential interrupt currents are limited only by
resistance of the breaker itself (28v/.04 = 700A).
I suspect this is where the original 700A figure came from
and was proffered as a "worst case" condition. Thing
is, the product is never installed in a way that this
condition can be realized.
Bob . . .
________________________________________________________________________________
| From: | "Troy Scott" <tscott1217(at)bellsouth.net> |
| Subject: | Crowbar CB "problem" |
Bob, Charlie, Eric, All,
If there's really a concern about the possible inappropriateness or lack of
reliability of a common CB in the Crowbar OVP application, why not just use
a fuse? It could be located in an easy-to-reach spot. We could carry a few
spares..... What's the big deal?
Regards,
Troy
________________________________________________________________________________
| From: | Fiveonepw(at)AOL.com |
| Subject: | Re: Crowbar CB "problem" |
In a message dated 08/01/2005 5:11:36 PM Central Standard Time,
tscott1217(at)bellsouth.net writes:
why not just use
a fuse?
>>>
One advantage of breaker is notification of OV event- you'll see it popped
out...
Mark
________________________________________________________________________________
| From: | Charlie Brame <chasb(at)satx.rr.com> |
| Subject: | Re: Diode orientation |
Bob,
Thanks for the reply. You, and others, pointed out that the small band,
regardless of the color, indicates the "cathode" end. That solved my
problem - the various colors had me confused. As you surmised, the
Navaid manual uses a "comic book" wiring diagram.
As to the need to hook the comm to the autopilot, I quote from the
Navaid manual:
" The diode installed in series with the push-to-talk line,
together with the wire connected from the PTT switch to pin 7, are used
to kill the signal to the servo while the PTT switch is depressed. This
prevents the servo from jumping around due to the presence of high level
RFI on the servo power lines. The servo stays engaged during the voice
transmission, but it does not move until normal operation is restored by
releasing the mike button."
The manual goes on to say that a metal airplane with shielded wires
probably will not have a RFI problem, but that a composite airplane with
unshielded wires probably will. My RV is metal, of course, but I have an
obvious RFI problem with my unshielded trim indicator circuitry, so I
figured connecting the diode as shown was good insurance.
Charlie
RV-6A N11CB
San Antonio
-------------------------------------------------------
> From: "Robert L. Nuckolls, III"
> Subject: Re: AeroElectric-List: Diode orientation
>
>
>
> >
> >Bob, et al,
> >
> >My Navaid installation manual recommends a diode between the Navaid pin
> >7 and the Comm PTT circuit. The Navaid schematic shows a black and white
> >diode with a large white area and a small black stipe on one end. The
> >white area is oriented toward the Comm unit and the black stripe
> >oriented toward the PTT circuit. However, the diode I received from B&C
> >is mostly black with a small grey stripe at one end.
> >
> >Can I assume that the large black end of the diode equates to the large
> >white end on the Navaid schematic?
>
>
> The descriptions you're making for the parts and wiring
> diagram are don't give us a clear image of the instructions.
>
> Most wire lead diodes have a "band" on one end and the color
> of the band is insignificant. It will be some color that
> contrasts with the body color of the diode itself.
>
> The banded end corresponds to the "cathode". In a diode's
> schematic, the "bar" touched by the arrowhead is the
> cathode while the arrowhead itself is the anode. Electrons
> flow through a diode in opposition to direction of arrow.
> See:
>
> http://www.aeroelectric.com/Pictures/Diode_Wiring_2.jpg
>
> Some folks are confused when they see diodes used for two
> different tasks like "steering" as shown in -A- and -B-
> and spike clipping as shown in -C- and -D-.
>
> Do you have a real schematic of the wiring were the
> bar and arrowhead are seen in the classic diode symbol
> . . . or is it a comic book wiring diagram that shows
> only pictures? Sounds like you're working with the latter.
>
> In this case, go by which end has a band on it irrespective
> of color. Do they say what this diode is supposed to do?
> I'm mystified by the need hook any part of your comm transceiver
> to the autopilot.
>
> Bob . . .
>
>
________________________________________________________________________________
| From: | "r falstad" <bobair8(at)msn.com> |
| Subject: | Two Mags & One Input to Electric Tach |
I would like to use a Radio Shack submini DPDT switch so my Westach/Westberg Mfg.
electric tach can read RPM on each magneto. I'm thinking of running a single
conductor shielded 18 AWG wire from each mag switch (the same wire I'm going
to use for the "P" leads) to the DPDT switch. I'll terminate the conductors
and the shields separately for each side of the switch so when I throw it, I
won't have the shield from the other "P" lead making contact as I would have to
do if I used a SPDT switch.
Does this sound like it will work?
Best regards,
Bob
________________________________________________________________________________
| From: | "Steve Sampson" <SSampson.SLN21(at)london.edu> |
Bob - before my machine crashed i had some simple software to read and modify Z-11
for instance. I had downloaded it from a reference on your web site. Cant
find it now. Can you point me to the downloads.
Thanks, Steve.
________________________________________________________________________________
| From: | Matt Jurotich <mjurotich(at)hst.nasa.gov> |
| Subject: | Re: crowbar method |
Bob et all
The part number for the breaker referenced below is?
Your supposition is correct. The breaker in B&C's test
stand for their regulators has experienced thousands
of crowbar events (150 A or so in 14v mode, 300A in
24v mode) and last time I checked with Tim, the breaker
in place today was the one I installed there about
15 years ago. Granted, it's a high-end product equal
to the miniature breakers used in the majority of our
aircraft at RAC.
Thanks
Matthew M. Jurotich
NASA/Goddard Space Flight Center
Swales contractor to the
JWST ISIM Systems Engineer
m/c : 443
e-mail mail to:
phone : 301-286-5919
fax : 301-286-7021
JWST URL: <http://ngst1.gsfc.nasa.gov
________________________________________________________________________________
| From: | "Paul McAllister" <paul.mcallister(at)qia.net> |
| Subject: | Electric Tail wheel tug |
Hi all,
I know this is a little off topic but I am searching for mechanical components
to construct an electric tail wheel tug. I need a small axle with a right angle
drive similar to a differential. I have been searching the WEB but I end up
with too many hits. I was thinking something from an electric wheel chair manufacturer
might be able to be adapted. If anyone could suggest a few URL's
to browse I'd appreciate it.
Thanks, Paul
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: crowbar method |
>
>
There are LOTS of part numbers. They are members of a class
of breaker offered to the aerospace and upper-end commercial
applications. Examples include:
http://www.aeroelectric.com/Pictures/circuitbreakers.jpg
http://www.ti.com/snc/products/controls/acb-2tc.htm
http://www.ti.com/snc/products/controls/acb-7277.htm\
http://www.ti.com/snc/products/controls/acb-7274.htm
http://aerospace.eaton.com/products/power_load_subsystems/circuit_breakers.html
There are plenty of other suitable breakers not the
least of which are the Potter-Brumfield products offered
by Wicks. They also offer the miniature breakers at
http://wicksaircraft.com/catalog/product_search_results.php/search=Y2lyY3VpdCBicmVha2Vy
B&C has the miniature breakers suggested above.
Aircraft Sruce offers the miniature breakers at:
http://www.aircraftspruce.com/menus/el/circuitbreakers.html
The list of suitable breakers is huge. The only breakers
that have given me pause for concern that have surfaced
in the OBAM aviation community are some miniature, toggle
breakers that cost about $3 each are offered in someone's
pre-assembled power distribution product. The name escapes
me right now.
Bob . . .
________________________________________________________________________________
| From: | Phil Birkelbach <phil(at)petrasoft.net> |
| Subject: | Re: Electric Tail wheel tug |
How 'bout a right angle drive for a drill?
...or go to a pawn shop and buy a big angle grinder and gut it. I bet
that gear box could take some abuse.
I once knew a guy that built a tug to pull his Bonanza around out of a
1/2" electric drill motor. You might also search around the hobby robot
builders sites. They have good sources for stuff like this.
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB - Finishing Up
http://www.myrv7.com
Paul McAllister wrote:
>
>Hi all,
>
>I know this is a little off topic but I am searching for mechanical components
to construct an electric tail wheel tug. I need a small axle with a right angle
drive similar to a differential. I have been searching the WEB but I end
up with too many hits. I was thinking something from an electric wheel chair
manufacturer might be able to be adapted. If anyone could suggest a few URL's
to browse I'd appreciate it.
>
>Thanks, Paul
>
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Crowbar CB "problem" |
>
>
>Bob, Charlie, Eric, All,
>
>If there's really a concern about the possible inappropriateness or lack of
>reliability of a common CB in the Crowbar OVP application, why not just use
>a fuse? It could be located in an easy-to-reach spot. We could carry a few
>spares..... What's the big deal?
Excellent question! In fact, some early American/Grumman products
did just that. Crowbar OV protection in the form of a 16v zener
(had to be a glass device, the plastic ones would blow up) downstream
of a field supply fuse. If the alternator ran away, the zener would
FALI SHORTED and take out the fuse. This was a dirt cheap, effective,
but ONE-SHOT protection method.
If you do get a nuisance trip, then it could not be reset in
flight. Further, the designers tied the fuse into the wire bundle
behind the panel. If the system ever operated, you had to replace
both fuse and zener. Not very user or mechanic friendly.
We elected to go with breakers since they were already in place
in our customer's inventories and a part of their standard bag-
of-tricks. Crowbar ov protection was slated to go onto Beech's
Model 38 (Turbine Bonanza). Seems that of ALL OV protection
systems available to Beech at the time, the regulator modified
with crowbar ovp was the only one that would catch a 70A, 12,000rpm
runaway 50x in a row and still meet specs on the 51st try. Unfortunately,
the program died (seems Bonanza wings wouldn't hold enough fuel
to make a turbine powered, go fast version fit Beech Marketing's
business model). The last time I saw the airplane, it was sitting
outside Bert Rutan's hangar at Mojave looking very much stripped
down.
http://www.aeroelectric.com/Pictures/38P.jpg
Burt got it when he split the sheets with Beech during the
Linden Blue era . . . all he wanted out of it was the
engine and panel mounted stuff.
In a message dated 08/01/2005 5:11:36 PM Central Standard Time,
tscott1217(at)bellsouth.net writes:
why not just use
a fuse?
>>>
One advantage of breaker is notification of OV event- you'll see it popped
out...
Yup, that works. But it's still takes a back seat to
ACTIVE NOTIFICATION of low voltage in the form of a
light flashing right in your face.
Bob . . .
________________________________________________________________________________
| From: | Phil Birkelbach <phil(at)petrasoft.net> |
| Subject: | Re: Crowbar CB "problem" |
You can put an LED and resistor in parallel with the fuse and this would
give you indication. We buy these little fused terminal blocks at work
that have this little circuit built in. The drawbacks are that you have
to have a little bit of a load downstream of the fuseblock or they don't
indicate properly. This may not be an issue in this case. Also you
can't troubleshoot the circuit with a voltmeter like you would think
because the LED will let a few milliamps through and you'll read voltage
downstream of the fuseblock even with a blown fuse.
Also keep in mind that this is a parts count increase to solve a problem
that seems to only exist on datasheets and not in the real world. My
plane has P&B circuit breakers and a crowbar OVM on each alternator, and
I ain't worried a bit. The point is to protect my $xxK dollars worth of
radios from the insane alternator not to protect the circuit breaker
from doing it's job. If I have an OV event and the breaker pops and
dies then I'll fix the OV and replace the CB, smiling the entire time
that my avionics are all oblivious to the fact that the event took place.
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB - Finishing Up
http://www.myrv7.com
Here's a cheesy circuit diagram...
+12Vdc -----+----(Fuse)-----+-----> Load
| |
+-\/\/\--(LED)--+
Fiveonepw(at)aol.com wrote:
>
>In a message dated 08/01/2005 5:11:36 PM Central Standard Time,
>tscott1217(at)bellsouth.net writes:
>why not just use
>a fuse?
>
>
>
>One advantage of breaker is notification of OV event- you'll see it popped
>out...
>
>Mark
>
>
>
>
________________________________________________________________________________
| Subject: | Electric Tail wheel tug |
| From: | "Mark R Steitle" <mark.steitle(at)austin.utexas.edu> |
Paul,
As I recall, there was a recent article in Kitplanes on how to build a
low budget tug from spare bicycle parts. I don't recall the exact
issue, but it was within the last six months.
Mark S.
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Paul
McAllister
Subject: AeroElectric-List: Electric Tail wheel tug
Hi all,
I know this is a little off topic but I am searching for mechanical
components to construct an electric tail wheel tug. I need a small axle
with a right angle drive similar to a differential. I have been
searching the WEB but I end up with too many hits. I was thinking
something from an electric wheel chair manufacturer might be able to be
adapted. If anyone could suggest a few URL's to browse I'd appreciate
it.
Thanks, Paul
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Diode orientation |
>
>Bob,
>
>Thanks for the reply. You, and others, pointed out that the small band,
>regardless of the color, indicates the "cathode" end. That solved my
>problem - the various colors had me confused. As you surmised, the
>Navaid manual uses a "comic book" wiring diagram.
>
>As to the need to hook the comm to the autopilot, I quote from the
>Navaid manual:
>
> " The diode installed in series with the push-to-talk line,
>together with the wire connected from the PTT switch to pin 7, are used
>to kill the signal to the servo while the PTT switch is depressed. This
>prevents the servo from jumping around due to the presence of high level
>RFI on the servo power lines. The servo stays engaged during the voice
>transmission, but it does not move until normal operation is restored by
>releasing the mike button."
>
>The manual goes on to say that a metal airplane with shielded wires
>probably will not have a RFI problem, but that a composite airplane with
>unshielded wires probably will. My RV is metal, of course, but I have an
>obvious RFI problem with my unshielded trim indicator circuitry, so I
>figured connecting the diode as shown was good insurance.
Hmmmm . . . some more of that "best practice" stuff.
I was afraid that's what you were going to say. I talked
with the Navaid guy (Doug something?) at OSH in '86 or '87 at
some length. This was before he graduated from a table in
the Flymarket to a booth in the commercial buildings. We
discussed EMC issues even then and I offered to help him make
his design RFI bullet proof. We discussed the same issue
several times in intervening years but I was never offered
the opportunity to contribute.
Words in the manual concerning shielding illustrate a lack
of understanding on the part of the writer. Shielding's benefits
are quite specific to breaking the capacitive (or electrostatic)
coupling mode between wires. It can have some limited benefits
in reduction of radiated interference where it becomes a sort
of short conduit, like on spark plug wires.
However, shielding as a general prophylactic measure against
RF intrusion or emissions is a very mixed bag. This is because
shielded wires in signal and power bundles are NEVER treated
as matched impedance transmission lines (al la coax antenna
feeders). I've seen cases where it helped not at all or even
made things worse.
The #1, sure fire, best bet, works-every-time technique is to make
one's black boxes immune to expected stress levels with appropriate
design of the input-output circuitry including use of filters
as needed.
Unfortunately, it seems that NavAid has not learned of this
fact in over 20 years. I'll suggest that risks to your
installation are quite low due to the metal airplane being
a strong attenuator of interference coming from antennas
outside. You might leave the diode out and see what happens.
It would be an interesting experiment to see how it goes.
Further, as a consumer of their products, you are entitled
to bang on their cage pretty good about this library-paste-
and-bubble-gum approach to EMC control. If you have occasion
to contact them in the future, you might suggest there's
this gray haired ol' fart in Wichita who is STILL waiting
to help them move their products into the present age.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Two Mags & One Input to Electric Tach |
>
>I would like to use a Radio Shack submini DPDT switch so my
>Westach/Westberg Mfg. electric tach can read RPM on each magneto. I'm
>thinking of running a single conductor shielded 18 AWG wire from each mag
>switch (the same wire I'm going to use for the "P" leads) to the DPDT
>switch. I'll terminate the conductors and the shields separately for each
>side of the switch so when I throw it, I won't have the shield from the
>other "P" lead making contact as I would have to do if I used a SPDT switch.
>
>Does this sound like it will work?
Sure. but you can make it simpler yet. See:
http://www.aeroelectric.com/Pictures/elect_tach2.gif
here I show the starter lockout circuit that prevents
operation of starter with the non-impulse coupled
magneto turned on. If you don't have/need this feature,
then the circuit can be implemented with one 2-pole
and a single pole switch. If you use shielded wire
from mag switches to tach, then ground at tach end
only. This eliminates the need for a third switch just
to service the tachometer signal.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: I'm happy...:) |
>
>
> With my all electric airplane (Lycoming with Emags and elctric fuel
>pumps only) I have found that by using a simple com radio (backup to GNS
>430) in receive mode and transponder I can get my total current draw
>down to a shade under 8 amps which fits nicely into the SD-8 backup.
>
>Using Bob's 3 buss design I can easily save my battery reserve to do the
>approach/run the lights for when I land.
>
>The above assumes I run only one fuel pump (I have one in each wing
>root) and one Emag.
>
>Having a Pmag on a dual alternator systems seems like two layers of
>redundancy to me...Do we agree?
You had "layers" before going to p-mags. Changing from e-mags
to p-mags is yet another layer. The neat thing about p-mags
is that they are totally independent of the electrical system
for normal operations in flight . . . this might suggest that
p-mags are not a layer on top of existing layers but a side-by-side
substitute for interdependent operations. A simple, very sensible
approach to ultimate system reliability.
Bob . . .
________________________________________________________________________________
| From: | Richard Riley <richard(at)RILEY.NET> |
| Subject: | Re: Crowbar CB "problem" question |
For those that have experience with an external regulator -
particularly one of the B&C regulators - how often do the nuisance trips occur?
If we're worried about the nuisance trips degrading field CB's, would
it be a reasonable fix to replace those CBs at annual?
________________________________________________________________________________
| From: | "Hinde, Frank George (Corvallis)" <frank.hinde(at)hp.com> |
Hmm...true and It saves yet another precious amp, significant when you
only have 8 of them in a high stress IFR/alternator goes south
environment.
I guess I was coming from the perspective that my FI pumps are as
critical as the ignitions. The chain is only as strong as its weakest
link. In other words there is no point in adding functionality to run
the igntion if the FI pumps are dead anyway.
For another 200 bucks to go from an EMAg to P mag I guess its pretty
much a moot point in a $90k aircraft...Still can't believe I'm spending
this kind of money!..:)
Frank
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Robert L. Nuckolls, III
Subject: Re: AeroElectric-List: I'm happy...:)
-->
(Corvallis)"
>
>
> With my all electric airplane (Lycoming with Emags and elctric fuel
>pumps only) I have found that by using a simple com radio (backup to
>GNS
>430) in receive mode and transponder I can get my total current draw
>down to a shade under 8 amps which fits nicely into the SD-8 backup.
>
>Using Bob's 3 buss design I can easily save my battery reserve to do
>the approach/run the lights for when I land.
>
>The above assumes I run only one fuel pump (I have one in each wing
>root) and one Emag.
>
>Having a Pmag on a dual alternator systems seems like two layers of
>redundancy to me...Do we agree?
You had "layers" before going to p-mags. Changing from e-mags
to p-mags is yet another layer. The neat thing about p-mags
is that they are totally independent of the electrical system
for normal operations in flight . . . this might suggest that
p-mags are not a layer on top of existing layers but a side-by-side
substitute for interdependent operations. A simple, very sensible
approach to ultimate system reliability.
Bob . . .
________________________________________________________________________________
| From: | "John Swartout" <jgswartout(at)earthlink.net> |
Rooting around the AEC website, I pulled up this diagram:
http://www.aeroelectric.com/PPS/Engine/Starter/PM_Starter_w_RunOn_Relay.
pdf
which is essentially Z-22 with what I believe is a bridge rectifier
added. I don't recall seeing mention of this anywhere else. Which is
the preferred architecture?
Also, I'm wondering about the sizing of the fuse (1A) on the line from
the Main Power Distribution Bus in the drawing referenced above. This
is much smaller than the 7A fuse on the 22AWG starter line in Z-13/8,
and much smaller than the 5A that would normally be used to protect a
22AWG wire. I wonder if there is a reason for the more expensive 1A
fuse.
Also, if the rectifier is recommended, would the Radio Shack 276-1185
called out for the E-bus normal feedpath also be appropriate here?
Thank you.
John
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Real data on OVP/etc (disinterested? DELETE) |
>
>Bob;
>
>Take a deep breath and read carefully and ignore any non technical parts but
>please consider the technical comments as worth considering as many are
>industry wide technical info.
>
>Sorry for your upset
I have never been more calm. There is ALMOST nothing you've stated
in your writings here that are worthy of an emotional investment.
> . . . but as usual you have missed my point and not addressed
>MY technical issues in a technical manner, merely replied with a personal
>assault (and perhaps properly deserved). There are some technical details
>here in this post as you requested and some are a repeat of my much earlier
>posts, but I digress. Here is some of the data you asked for.
>I am still waiting for ANY worst case design analysis showing any of your
>designs is usable in all likely applications. Some of the possible false
>tripping have been reported by buyers (not builders) of the OVP and all who
>contacted me wanted to remain anomalous (nor were they interested in a
>refund), just a good approach to the design issue as Vans says to not use
>any OVP design (yours or similar approaches).
Which only illustrates the ignorance of our customers
promulgated by your rhetoric and Van's equally ignorant
advice. It may well be that those customers were experiencing
the same difficulty that we discovered on the Bonanzas which
we were happy to rectify for Raytheon and would have been
equally happy to rectify for others except that they'd
bought into a bill of goods that painted us as incompetent.
The only case I was made privy to, the pilot MANUALLY SWITCHED
the alternator on and off under load. It did not involve
a nuisance trip. In fact, I doubt that ANY of the failures reported
to Van involved real nuisance trips . . . but it's an easy thing
for unhappy customers to improperly assign blame given some
highly touted but mis-informed opinions being circulated.
> As we have no info on the sold
>OVP design, its not possible to accept your statement that only the builders
>versions are at fault. I for one wonder why the sold version would be any
>different schematically.
For very good reasons which I would have provided if you
had asked. The sold versions are the same DIY version of
some years ago before the MBS4991 went obsolete. B&C did
a lifetime buy of the part to continue production of that
design but we needed another approach for the DIY circuit (which was
built, tested, qualified and incorporated into some production
units - except for the toe stubber that Ken pointed out
earlier this week).
>You have suggested many times that somehow the Vans rebuilt alternators have
>poor quality regulators and that is why they fail at a extremely hi rate
>when used with your OVP. From what little data I could find its a failure
>rate of 10% or much higher. Clearly something unique in the application of
>the wiring in Vans designs or ????? Some were purchased OVP and not built up
>units.
It was a hypothesis . . . .do you have another? But let's not
mix apples and oranges. The style of OVP has nothing to do
with the failures of Van's alternator. The very act of switching
the alternator OFF while loaded seems to be the trigger event.
This happens whether it's an ov trip from a crowbar module, Eric's
OVP module, or simply operating the switch on the panel. I'm
certain that it's a load-dump event that kills the alternator's
own regulator.
This is an issue SEPARATE from and not affected by style of OV
protection.
>"Rebuilt" alternators is really a false name in the industry. They are only
>repaired (what is failed is replaced, what still works is not replaced) and
>the ND 60 amp unit has been around for at least 25 years. Many units have
>been "rebuilt" several times. I contacted several major rebuilders around
>the country (including Bosch) as well as a couple of local ones and found no
>one replaces anything still working. Not even bearings were normally
>replaced in some cases. Thus a "new rebuilt" alternator might have an
>original 25 year old regulator or a cheep low quality import replacement or
>a modern but still low cost replacement. None admitted they used OEM (ND)
>regulators as replacements. The typical reply was "price competition"
>prevented that approach. Thus its not possible to single out Vans as having
>poorer alternators than others.
>
>The comments that in affect state my OVP is not the problem its Vans low
>quality rebuilds is what is upsetting. (MY S%&T does not smell :-) )
I've never said that my design could not have been root
cause of failures in Van's alternators due to any
particularly "golden" design. What I said was that Van's
alternators were failing because they were being unloaded
by mis-use of switches to control the alternator that were
PART of the ov system . . . the same damage would have
happened irrespective of who's ov module was used . . . or even
if no ov module is included in the b-lead control concept.
Eric currently publishes an ov protection scheme utilizing
the Killovac contactor which will fix the contactor performance
issue . . . but guess what? It will still kill alternators
for exactly the same reasons as before.
>Then I contacted a design engineer in the semi industry responsible for the
>modern one-chip regulator (not the one used by ND) and described the problem
>we were having. The reply was the design would protect against the normal
>load dump but was unlikely to survive a contactor contact arcing and the
>opening a loaded output "B" lead. This agrees with several different
>automotive test requirements for alternator design testing. The industry is
>designing to the automotive equivalent of the aircraft DO-160 which is more
>severe.
>
>At present the only known reasonably priced contactor RATED to open the "B"
>lead is the Kilovac. The common contactors available are not rated to open
>the voltages likely to be found under fault conditions.
Agreed. Which address only ONE issue. Contactor performance
as a b-lead controller. It has no bearing on either style
of ov protection used or on failures of alternators due to
load-dumping.
>I quote from a major relay manufacturers web site for contact application.
>
> "Improper or excessive suppression can cause the relay to suffer from a
>long release time, slow contact transfer, and contact bounce on break. All
>of these conditions will increase contact arcing when load switching, which
>will reduce relay life dramatically.".
>
>One site http://relays.tycoelectronics.com/kilovac/appnotes/transients.stm
>goes on to compare six different methods of coil "spike suppression" Its
>interesting to read this table and see that the common diode is the LAST
>choice and the Bi directional Zener (read bi directional transorb). There
>are similar tables in the USA and Europe and ALL suggest the last method of
>choice is the simple diode. The simple diode works as long as the contacts
>are carrying low currents and non inductive loads. In the case of the
>alternator its a very different matter as the unloaded unregulated
>alternator voltage can jump to hundreds of volts during the contact bouncing
>during opening even with the best coil suppression method thus the need for
>the Kilovac which is rated at hundreds of volts.
This is yet another isolated issue that goes toward potential slowing
of contact spreading velocity during opening. I've done extensive
testing and published results that show marked DELAY in contact opening
but not a significant slowing of spreading velocity. Tendencies to arc
during opening were exactly the same whether one used no diode,
a bi-directional Transorb or a plain diode.
If one is worried about opening delay, the Transorb is the way to
go. If one is concerned about best life for the controlling switch,
the diode is the best way to go. Since my designs didn't care about
delay time, I opted to stay with diodes.
See exemplar test plots representative of lots of tests on a variety
of relays and contactors:
http://www.aeroelectric.com/Pictures/704-1DelayNoDiode.gif
http://www.aeroelectric.com/Pictures/704-1DelayWithDiode.gif
http://www.aeroelectric.com/Pictures/704-1OpeningTimeNoDiode.gif
http://www.aeroelectric.com/Pictures/704-1OpeningTimeWithDiode.gif
>I find the use of the simple diode across relay contacts one of the most
>widespread miss information in the industry. IF ""Joe"" does it, it must be
>OK ,or if it was not good why are relays available with one built in?. It's
>very simple engineers are lazy and copy what others do far too often. Also
>it works in 99.9% of the cases. It does not work in a "B" lead contactor
>application however. Manufacturers will build what the engineers want
>regardless of its design value.
How is it mis-information if testing is used to deduce and
select from one of several controlling features? When diodes
were FIRST placed across the contactor coils in mid 60's, Transorbs
were not around . . . although we COULD have applied a variety
of spike snubbing techniques such as resistors or resistor-capacitor
networks.
The plain diode was used for decades across coil contactors
with great success for eliminating arc-induced wear on
controlling switches. Now comes the folks who are sifting the
grains of sand looking for the next quantum jump in relay/contactor
performance and the new kid on the block (Transorb) offers yet
another opportunity for improvement.
The question not asked and answered is: Do contactors and relays
in light aircraft operated enough cycles per hour, month, year
or even lifetime of the airplane for there to be even a measurable
improvement in service life of the device? A battery contactor
operates very lightly loaded and into a largely resistive load
and only once per flight cycle. Perhaps 50-100 times per YEAR
in a SE light aircraft. Starter contactors get the crap kicked
out of them once every flight cycle . . . which is why they're
specifically designed to take this extraordinary abuse. In BOTH
cases, use of a diode across the coil provides the same demonstrable
benefits for increasing life of the controlling switch since
we "discovered" them in 1965.
I'm not for a moment suggesting that substituting Transorbs for
diodes is a bad thing to do . . . but I object to any inferences
that my suggestions that diodes are "okay" is a promulgation of
"mis-information." I've been to the workbench, got out the test
equipment and demonstrated to my satisfaction that there is
no value in promoting Transorbs over diodes for the ways I
show them in my drawings.
>I have demonstrated this in my testing and I suspect its repeatable by you
>if you use a common contactor from Wicks for example. The contactor I used
>was from Wicks. In one case the bounce duration was quite long and included
>many bounces.
Opening bounce? I'm having trouble visualizing how contacts initially
moving apart reverse direction and move back together. What's the
forcing function? Bounce on closure is predictable and understandable.
I'd really like to repeat your experiment here too . . . please
show us the setup.
>My conclusion is never use a "rebuilt" internally regulated alternator with
>ANY OVP device that might false trip or trigger on a short transient.
This doesn't compute. Adding ANY form of b-lead control to ANY
internally regulated alternator is an adventure into unknown risk.
It has nothing to do with style of ov protective devices . . . false
tripping or otherwise. If one subscribes to the paradigm of being able
to CONTROL one's engine driven power source from the panel, then we
agree that a b-lead contactor is called for in every installation of
an internally regulated alternator.
Now, there is RISK that the alternator can be damaged by simply
turning it OFF while loaded whether the system included OV protection
or not.
> With
>a brand new ND alternator available for $300+ and the demonstrated failure
>rate in the auto industry being so low its unlikely any of us will ever see
>a "fail hi" condition in a lifetime of flight. Van does not recommend any
>OVP and with a modern regulator I agree its addition only reduces system
>reliability. The Fail HI mode of regulator failure is a very low
>probability in the failure modes of the modern regulator . Any failure of
>any type is extremely low in today's new production ND alternators.
Low . . . but not zero. Recall Jack's post of just last week:
--------------------------------
George: The alternator that failed was a nippon denso, 60 amp,
internally regulated. I'm not sure that my experience should cause
others to avoid this unit. I know that hundreds of airplanes are flying
successfully with them. However, if you read Bob's most recent post,
you might decide to avoid all internal regulated alternators.
Bob: As soon as I pull the fuel guage, I'll send it too you. What
address? thanks, jack
---------------------------------
>Use of any OVP has the potential of failing the alternator when it trips for
>what ever reason so IF a OVP is used it needs to be extremely reliable under
>all design conditions. It should never trip unless the OV is clearly of long
>duration. The AEC OVP device trips in a few milliseconds and really should
>not trip unless the OV is longer than what one might expect from a major
>load dump.
Agreed. But here you're substituting your design goals without
regard to the goals of our customers (who cited DO160/MS704) when
time constants were selected for the ov trip dynamics. The nuisance
tripping we've experienced has NOTHING to do with the OV sense
circuit and everything to do with dv/dt sensitivities of the SCR
which has shown that there are antagonistic events in SOME
systems that are NOT suggest by DO160/MS704.
After our epiphany, we made adjustments to the circuit for all
new production and for anyone who was plagued with the condition
in the field at no charge. This is a DISCOVERY of a phenomenon
not previously considered (by industry standard practices). No
amount of analysis would have predicted the condition we were
told did not exist (or at least was not previously identified).
The new requirement did not come to light until the Bonanza
production line produced a series of REPEATABLE EXPERIMENTS
critical to identification of root cause and deduction of remedies.
>YOU agreed there were cases of false tripping yet you failed to properly
>analyze your design. There was absolutely no reason for a real lab test and,
>in fact testing was a near total waste of time, as the false tripping
>depends on a specific implementation of the classic schematic. How do you
>expect to build all variations of a schematic??
You cite facts not in evidence. EVERY instance of a customer
reporting a nuisance trip problem has been dealt with in
a positive way if they only came forward with their
complaint. Just a few days ago, I upgraded an OV module
that worked as advertised for 4 years but became irritated
by a new accessory in the airplane.
We DID analyze the design, deduced modifications to fix the
problem, and offered the fix to anyone who needed/wanted it
at no charge.
>How can there be repeatable tests when several major components have
>important design tolerances or variables in the 5x or 10x range of
>tolerances. Battery internal resistances of 5-1 or more, CB resistances of
>10-1 or more. Schematic is one thing wiring diagram is another (how a
>schematic is implemented and where wires are connected along a common line
>in a schematic can and often does greatly affect the results.
I've given you the data that supports both my analysis and
test results. You still haven't told me what breaker you've
tested where the manufacturer says it goes tits-up on a 50x
overload.
>The time tested and standard method of circuit analysis is on paper with or
>without the help of software;
> However the use of PC625 and the very similar PC680 are very popular
>around here as are the use of dual batteries often simple wired directly in
>parallel.
The batteries are not the controlling factor. Wiring and breaker
resistances are. Lets assume ZERO battery resistance but we still
have 0.04 ohms of breaker resistance and a couple of feet of
20AWG wire for another .04 ohms when combined with a 2v drop
across the SCR yields about 130 amps of crowbar current. If it
would make you feel better, we COULD add the admonition to our
installation manuals not to install the crowbar module or any
of the LR series regulators with zero length wires . . . but given
that most folks locate their equipment some distance from the
bus, that worry wasn't high on our list of concerns.
>You used 0.035 ohms for the CB and got trip times of a few MS. I used a CB
>from Wicks and measures it at 0.003 ohms and it tripped repeatetly in the
>50-70 ms range. Yes the data seems illogical but my data is repeatable here
>and I accept your data also as factual.
What was the brand and part number of this .003 ohm breaker?
Results you're reporting are so astounding that they
BEG for a repeated experiment. Please afford me the courtesy
of knowing how to do it.
I've uploaded data sheets on breakers I find in Wicks catalog
to
http://www.aeroelectric.com/Mfgr_Data/Breakers/Potter_Brumfield
The two P&B data sheets speaks of 0.030 +/-30% for max
breaker resistance on 5A breaker. Of course, this is a MAX
value. Did you find an exemplar breaker that presented a
resistance 1/10th this value?
I'm amazed that one can fabricate a 5A breaker heater with so
small a resistance. I've measured dozens of breakers by Woods,
Mechanical Products, Klixon, and Eaton-CH and they all agree with
their data sheets to present about 30-40 milliohms of series resistance
in a 5A breaker. Smaller breakers are markedly higher in resistance.
>There is no way you can reproduce my test data unless you use the exact same
>parts.
ABSOLUTELY! DEAD ON! By the same token, I cannot evaluate
the validity of your test data without knowing what parts you
used. You keep hammering me with these near zero-ohm breaker
values and I can't find anything approaching these values
in any products I can put my hands on.
>This is the fallacy of your requirements that the test must be
>reproducible by you to be valid.
???? Paul, this is a truly astounding statement from someone
to claims to be an engineer. No sir! For CLAIMS made by
ANALYSIS of test results to be valid, they should be
CAPABLE of being repeated by anyone who wishes to do
the work. OF COURSE this requires a complete disclosure
of all materials and techniques used. Remember the cold fusion
guys of about 15 years ago? They made claims that begged
critical review by repeated experiment. Remember Dave Blanton's
240 hp, 6-cyl Ford conversions? How about Jim Bede's super-sonic
OBAM product? Geesh! Just watch late night TV and you'll get
tons of information most of which would not stand up to
critical design review and repeated experiments. But the gullible
consumer is not privy to real data or experience that validates
the propagandist's claims. You might as well be watching a
Siegfried and Roy show and believing those lions really disappear.
Until they show me how I can make lions disappear, it's nothing
but propaganda with an agenda. In their case, the agenda is
is entertainment which I do enjoy. What's your agenda sir?
Data for repeatable tests are a COURTESY that REAL scientists
offer each other as and AID to investigating any phenomenon.
I expected and requested no more of you and I was fully transparent
in everything I used to base my claims. I've built a career
on repeatable test results in the lab and in my customer's
airplanes. Yes, things slip by sometimes - the only thing
we can do then is act in a responsible way to rectify
the problems as they arise.
>Perhaps its valid where the circuit
>variables are not so dependent on individual parts used but in this case the
>parts variation is so huge they prevent repeatable tests. Both tests are
>reasonable examples of the overall design as documented on your web site and
>neither are a worst case example as only a proper analysis can define the
>range of design results.
>
>ANY design that is to be reproduced must be analyzed using the specified
>data sheet parts variations (and either specify the exact parts of consider
>all the likely parts brands that could apply) and for general use NEVER
>publish a design that violates the data sheet under any condition or assumes
>parameters not specifically printed in the data sheet.
Pleeeasssss, purdy pleeeaasse, show me the data sheets.
>In any event I see no reason to continue posting.
That's fine too.
I sat in a meeting yesterday for several hours looking at about 50
pounds of paper on the table that included failure mode effects
analysis, reliability studies that assured us we were buying
a 7,000 hour MTBF product, test reports out the wazzoo,
detailed worst case analysis, etc. etc. These papers
presumably defined a system that we paid $millions$ for and
according to all the analysis, should be the golden product.
It won't run more than 10 hours without annunciating a failure
and causing our customers great concern and billing our coffers
many $killo$ of warranty csots. This golden system monitors
dozens of potential problem areas and if you believe the
marketing hype (we did) . . . it's the safest system ever to
fly.
Problem is, the designers forgot to offer a way to tell which
one of 5 dozen faults tripped out the system. Further, as far
as the FAA is concerned, the system is blessed (it passed all
the qual tests) and is carved in stone. Any changes (to
upgrade performance or to even fix simple nuisance trips) are
horrifically expensive and time consuming to implement.
I have a proven, flight-tested alternative system that has run fault
free for hundreds of hours. The system that works was afforded
perhaps 5% of the analysis and testing compared to the system that
doesn't work. Further, ALL operating characteristics of the
working system are observable at any time . . . INCLUDING
those characteristics that might produce shut downs.
If you want to apply the tools of detailed analysis to
the crowbar (or any other) ov protection system, you
must first cite ALL sources, magnitudes and configuration
of your hypotheticals. Only then may we debate results to your
heart's content as scientists. Analysis is a tool. It depends
on proper application of good input data and lucid interpretation
of results. These things are BEST conducted as cooperative
critical reviews where everyone's focus is on doing the
best thing for our customers and students and not lobbing
cabbages.
Now, HERE is where I DO get tense . . .
I'll continue to object to your rhetorical, unfounded
attacks on "my approach" when I'm the one who has thousands
of happy customers. The few secret, unhappiest customers are
those who accepted your hip-shot assessment of my engineering
integrity and business ethics to the extent that they (according to
you) won't take advantage of remedies I'm begging to offer. Further,
you have deprived ME of benefits for having field experience upon
which to deduce root cause of problems and to craft improvements
to my products and servics.
One of the KEY attributes of our society that served to build
us into an economic powerhouse in record time is that sacred
relationship between honorable suppliers and consumers who
walk away from every deal happy or at least free of fraud
or encroachment on their property.
How many times on this List have I encouraged individuals
with questions or complaints about any product to communicate
FIRST with the manufacturer/supplier? Give the supplier
an opportunity to do the right thing and support their
customers to the best of their ability and/or business model.
You have injected yourself into the relationship between
me and individuals who have invested in my goods or services.
Your actions, no matter how well intended, are costing me
undeserved loss of both good-will in the marketplace and valuable
feedback from my customers. Your actions have produced unhappy
customers AND suppliers through no fault of either. There are
no civil words in my vocabulary to adequately express how much
this displeases me.
If you do post, show me the data. If you choose not to post,
I wish you well but I'll continue to worry about your crusades
against myself (and probably others) who are not deserving of your
dishonorable disservice.
Bob. . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Z-22 question |
>
>
>Rooting around the AEC website, I pulled up this diagram:
>
>
>http://www.aeroelectric.com/PPS/Engine/Starter/PM_Starter_w_RunOn_Relay.
>pdf
>
>
>which is essentially Z-22 with what I believe is a bridge rectifier
>added. I don't recall seeing mention of this anywhere else. Which is
>the preferred architecture?
Good find sir. I'd intended to update Z-22 to this configuration.
A builder wrote me some time ago asking about spike catchers
for BOTH the S704-1 AND the starter's built in contactor/solenoid.
Given that we needed TWO diodes and given further that wire-leaded
diodes are often clumsy to work with, this seemed like a new
opportunity for the diode bridge rectifier. Note that in this
case, we use two of the four diodes to accomplish the tasks
suggested by his query.
>Also, I'm wondering about the sizing of the fuse (1A) on the line from
>the Main Power Distribution Bus in the drawing referenced above. This
>is much smaller than the 7A fuse on the 22AWG starter line in Z-13/8,
>and much smaller than the 5A that would normally be used to protect a
>22AWG wire. I wonder if there is a reason for the more expensive 1A
>fuse.
7A was necessary to control the intermittent duty contactors
thought 20AWG wire to improve contactor performance under high
loads on battery.
1 to 5 A are fine for 22AWG wire that only drives the S704-1 relay.
B&C charges the same price for all values of the ATC fuse from
1 to 30 amps.
>Also, if the rectifier is recommended, would the Radio Shack 276-1185
>called out for the E-bus normal feedpath also be appropriate here?
Sure . . . mounts with one screw, doesn't need insulators, wires
with 1/4" faston tabs. What could be easier?
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Crowbar CB "problem" question |
>
>For those that have experience with an external regulator -
>particularly one of the B&C regulators - how often do the nuisance trips
>occur?
>
>If we're worried about the nuisance trips degrading field CB's, would
>it be a reasonable fix to replace those CBs at annual?
I guess that depends on the breaker. The ones I sold and
B&C sells are quite robust and don't present a service-life
issue. I lost track of LR series devices fielded when it passed the
2,000 mark years ago. I suspect it's over 3,000 now.
Until the Bonanza experience, we had a handful of reports
of nuisance trips virtually all of which were fixed by
identification and mitigation of the noise at the antagonist.
I've not been closely coupled to the B&C experience for several
years now so I cannot report first-hand about problems with
fielded systems. If there were any kind of crisis, I suspect
I would have had a call from them. You can contact Tim at
B&C if you're needing more current data.
There is a breaker in the B&C acceptance test fixture
that has been subject to test trips from every LR series
regulator produced since day one. As far as I know it's
still there . . . but again, you'll have to ask Tim.
If the breaker fails, it will present you no greater
an issue than for failure of any OTHER part in the
alternator system. That's what we design for . . . failure
tolerance.
This is a tempest in a teapot folks. Aside from an
admonition not to install B&C or AEC products with zero
length leads and breakers purchased from Duckwalls,
I can deduce no reason to be worried.
Bob . . .
________________________________________________________________________________
| From: | Joseph Larson <jpl(at)showpage.org> |
| Subject: | Re: Crowbar CB "problem" question |
It's time to display my ignorance.
On Aug 2, 2005, at 1:37 PM, Robert L. Nuckolls, III wrote:
>
> This is a tempest in a teapot folks. Aside from an
> admonition not to install B&C or AEC products with zero
> length leads and breakers purchased from Duckwalls,
> I can deduce no reason to be worried.
I don't know what Bob means here. I haven't been able to keep up
with the entire conversation, there's just been so much going on with
it. I've been trying to read it, but I think it would be a full time
job.
What is meant by "zero length leaders" ? Bob, are you saying that
there's a right way and a wrong way to install these products?
Is there a particular issue with breakers from Duckwalls?
Color me ignorant.
-Joe
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Crowbar CB "problem" question |
>
>It's time to display my ignorance.
>
>On Aug 2, 2005, at 1:37 PM, Robert L. Nuckolls, III wrote:
> >
> > This is a tempest in a teapot folks. Aside from an
> > admonition not to install B&C or AEC products with zero
> > length leads and breakers purchased from Duckwalls,
> > I can deduce no reason to be worried.
>
>I don't know what Bob means here. I haven't been able to keep up
>with the entire conversation, there's just been so much going on with
>it. I've been trying to read it, but I think it would be a full time
>job.
>
>What is meant by "zero length leaders" ? Bob, are you saying that
>there's a right way and a wrong way to install these products?
The right way is "follow the instructions". You have to go
out of your way to install these in a manner that increases
risks of problems. Even if there are "problems" risks to
safety of flight are tiny. The reference to "zero length"
leads is a mild side swipe at an experiment that exposes
vulnerabilities to the crowbar ov protection system by setting
it up in a manner that does not represent any way it would
be installed in an airplane. Obviously, we use WIRE to hook
things up and that wire has length because we can't stack
all the electrowhizzies into a 1 cubic foot space in the
airplane.
Bottom line is that the worst of the worrisome worst
case scenarios just doesn't happen.
>Is there a particular issue with breakers from Duckwalls?
That was a tongue in cheek reference to circuit breakers
of unknown pedigree. I'm aware of no "mainstream" supplier
to the OBAM aircraft community that supplies breakers
I cannot recommend.
Take a peek at:
http://www.velocityaircraft.com/Velocity%20Store/Avionics,Electrical,autopilots,instruments/prewired_systems.html
The breakers used in this assembly are not fabricated to
any design requirements that I can identify. Unsafe? No,
they'll probably open up when overloaded just as designed.
Robust? I don't think so, but I don't know either. Rather
than speculate, I'll choose to suggest you purchase from
Wicks, B&C, Aircraft Spruce, or our friend up at Steinair.
It's easy to suggest known good sources and very difficult
to identify and/or predict questionable sources.
>Color me ignorant.
But obviously willing to learn . . . keep up the good quesitons!
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Electric Tail wheel tug |
>
>
>Hi all,
>
>I know this is a little off topic but I am searching for mechanical
>components to construct an electric tail wheel tug. I need a small axle
>with a right angle drive similar to a differential. I have been searching
>the WEB but I end up with too many hits. I was thinking something from an
>electric wheel chair manufacturer might be able to be adapted. If anyone
>could suggest a few URL's to browse I'd appreciate it.
Consider modifying a small electric winch mechanism. Maybe
something from Harbor Freight? Most of the low cost, high
torque speed reducers take advantage of the one-step, high
mechanical advantage of a worm gear mechanism that might
offer both a motor and gearbox assembly suited to your
task.
Worm gears are horribly inefficient but in this application,
they might just be what you need.
Also check out the following offerings from ebay:
7534404208
7534284982
7704814350
7535764492
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: CAD software |
>
>
>Bob - before my machine crashed i had some simple software to read and
>modify Z-11 for instance. I had downloaded it from a reference on your web
>site. Cant find it now. Can you point me to the downloads.
http://www.aeroelectric.com/CD/AEC8_0.zip
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Electric Tail wheel tug |
>
>How 'bout a right angle drive for a drill?
>
>...or go to a pawn shop and buy a big angle grinder and gut it. I bet
>that gear box could take some abuse.
>
>I once knew a guy that built a tug to pull his Bonanza around out of a
>1/2" electric drill motor. You might also search around the hobby robot
>builders sites. They have good sources for stuff like this.
>
>Godspeed,
>
>Phil Birkelbach - Houston Texas
Great suggestions.
Bob . . .
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
| Subject: | The fatwire ground blues . . . |
--> AeroElectric-List message previously posted by: "Robert L. Nuckolls,
III"
>Comments/Questions: I am implementing your dual alt/batt/buss system on my
>GA-III. I fried a ground wire(lots of smoke)due to a loose battery ground
>connection while cranking the starter! The fried wire went to the fuel
>flow sensor mounted on the engine block. The starter return current tried
>to use the smaller wire due to a loose battery ground connector to the
>Alt-Battery. Should the sensors(Vision Micro) mounted on the engine block
>(fuel flow, fuel press, oil temp, oil press) have ground wires that
>connect to the engine block? These wires can be potential return paths for
>heavy starter current with a loose (-) battery connection.
8/2/2005
Hello Bob Nuckolls, I am concerned that your correspondent may have bigger
problems than just a fried wire. I quote from the Vision Microsystems
installation manual:
"DO NOT: ground the transducer body to any part of the aircraft, if
possible. Otherwise INSURE that the engine is EXTREMELY well grounded."
Emphasis provided by the author. The manual also contains specific
directions not to mount some of these transducers directly on the engine.
The wiring diagram for this system shows all wires (which are color coded)
from these transducers being connected to a specific pin in the DPU (Data
Processing Unit). I don't know how one could come up with a "ground wire" to
connect to the engine block.
It is possible that the DPU was damaged while the wire was being fried.
"When (before) all else fails ..... read the instructions".
OC
________________________________________________________________________________
| From: | "Steve Sampson" <SSampson.SLN21(at)london.edu> |
| Subject: | Fw: CAD software |
----- Original Message -----
From: Steve Sampson
Subject: CAD software
Bob - before my machine crashed i had some simple software to read and modify Z-11
for instance. I had downloaded it from a reference on your web site. Cant
find it now. Can you point me to the downloads.
Thanks, Steve.
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: CAD software |
>
>
>Bob - before my machine crashed i had some simple software to read and
>modify Z-11 for instance. I had downloaded it from a reference on your web
>site. Cant find it now. Can you point me to the downloads.
http://www.aeroelectric.com/CD/AEC8_0.zip
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: The fatwire ground blues . . . |
>
>
>--> AeroElectric-List message previously posted by: "Robert L. Nuckolls,
>III"
>
>
> >Comments/Questions: I am implementing your dual alt/batt/buss system on my
> >GA-III. I fried a ground wire(lots of smoke)due to a loose battery ground
> >connection while cranking the starter! The fried wire went to the fuel
> >flow sensor mounted on the engine block. The starter return current tried
> >to use the smaller wire due to a loose battery ground connector to the
> >Alt-Battery. Should the sensors(Vision Micro) mounted on the engine block
> >(fuel flow, fuel press, oil temp, oil press) have ground wires that
> >connect to the engine block? These wires can be potential return paths for
> >heavy starter current with a loose (-) battery connection.
>
>8/2/2005
>
>Hello Bob Nuckolls, I am concerned that your correspondent may have bigger
>problems than just a fried wire. I quote from the Vision Microsystems
>installation manual:
>
>"DO NOT: ground the transducer body to any part of the aircraft, if
>possible. Otherwise INSURE that the engine is EXTREMELY well grounded."
>
>Emphasis provided by the author. The manual also contains specific
>directions not to mount some of these transducers directly on the engine.
>
>The wiring diagram for this system shows all wires (which are color coded)
>from these transducers being connected to a specific pin in the DPU (Data
>Processing Unit). I don't know how one could come up with a "ground wire" to
>connect to the engine block.
>
>It is possible that the DPU was damaged while the wire was being fried.
>
>"When (before) all else fails ..... read the instructions".
>
>OC
Very perceptive sir. He DID find another loose ground at
the engine. Root cause wasn't a loose battery ground.
Bob . . .
________________________________________________________________________________
| From: | Fiveonepw(at)aol.com |
| Subject: | Audio Iso Amp problem |
Bob-
My kit-built amp exhibits poor audio input from my Microair 760- the audio is
"clipped?" where perhaps 1/3 of the signal gets through resulting in barely
audible reception. By "clipped" I mean it is like I will hear perhaps 100 msec
of audio with about 200 msec silence between. (WAG at time intervals) The
audio alarm from my EIS4000 engine monitor sounds perfect, however- a nice
clean "beep" simultaneously with the alarm light. I changed the 150 ohm input
resistors with 180s with no noticeable difference.
It is the same unit I sent you for testing some time ago and you reported it
was fine. Autocad dwg of audio system available if desired. Suggestions?
Thanks- Mark Phillips
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
| Subject: | Crowbar CB "problem" question |
AeroElectric-List message previously posted by: Richard Riley
<>
8/3/2005
Hello Richard, 100 hours plus on my plane with an externally regulated
(B&C), gear driven, 60 AMP alternator with no nuisance trips.
Replacing CB's can be a bitch because frequently they are fastened 2 or 3 or
more to a brass bar. It can take a significant amount of unfastening and
then reassembling to replace one CB.
OC
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Audio Iso Amp problem |
>
>Bob-
>
>My kit-built amp exhibits poor audio input from my Microair 760- the audio is
>"clipped?" where perhaps 1/3 of the signal gets through resulting in barely
>audible reception. By "clipped" I mean it is like I will hear perhaps 100
>msec
>of audio with about 200 msec silence between. (WAG at time intervals) The
>audio alarm from my EIS4000 engine monitor sounds perfect, however- a nice
>clean "beep" simultaneously with the alarm light. I changed the 150 ohm
>input
>resistors with 180s with no noticeable difference.
>
>It is the same unit I sent you for testing some time ago and you reported it
>was fine. Autocad dwg of audio system available if desired. Suggestions?
Any changes to the series input resistors should be made in 1x/0.5x steps.
For example, if you want to reduce gain of any one channel, the MINIMUM
useful increase would be from 150 to 300 ohms. If still too hot, go to
600 ohms, etc.
By the same token, if you need more gain, reduce a 150 ohm resistor
to 75 ohms first, then 36 ohms.
I'm hearing that some radios like to be "loaded" heavier on their
phones output signals than what the amplifier provides. Before you
change the 180 to anything else, try putting anything from 50 to
100 ohms ACROSS the Microair 760's headphones output leads.
What your describing sounds more like some kind of bias shift
than overloading. The "dummy" load may help more than anything
else. Let us know what you find.
I've had some good feedback from about a dozen builders of the
audio isolation amplifier with some suggestions for improvements.
I'm considering a second generation version . . . but to fit in
the same package, we'll have to go surface mounted parts which
is probably more than most builders want to tackle. If we do
it, the amplifier will offered as a plug-n-play assembly.
There's one going into a certified ship under a 337 installed
by what appears to be a really savvy technician. I asked him
to feed back impressions and suggestions too. I think this
gizmo is ripe for an upgrade but there's no reason we can't
make it do what you need done.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Crowbar CB "problem" question |
>
>AeroElectric-List message previously posted by: Richard Riley
>
>
><particularly one of the B&C regulators - how often do the nuisance trips
>occur?
>
>If we're worried about the nuisance trips degrading field CB's, would
>it be a reasonable fix to replace those CBs at annual?>>
>
>8/3/2005
>
>Hello Richard, 100 hours plus on my plane with an externally regulated
>(B&C), gear driven, 60 AMP alternator with no nuisance trips.
>
>Replacing CB's can be a bitch because frequently they are fastened 2 or 3 or
>more to a brass bar. It can take a significant amount of unfastening and
>then reassembling to replace one CB.
If one uses fuseblocks for all circuits EXCECPT the
alternator control lead as depicted in the Z-figures, then
a single breaker is usually very easy to replace. But if one uses
a reasonably robust breaker as described in previous posts,
risk to the breaker is WAY down on one's list of maintenance
concerns and then only after experiencing a bucket full of
nuisance trips.
Let's FIX the nuisance trips for the sake of our breakers,
nerves AND good consumer/supplier relationships.
Bob . . .
________________________________________________________________________________
| From: | joelrhaynes(at)aol.com |
| Subject: | Z-11 question for the electrically challenged |
Bob,
I will shortly be wiring my RV-7a according to your Z-11 schematic and will be
using Van's internally regulated 60 amp alternator. If I choose not to employ
OV protection, I assume that I simply connect terminal #4 of the Battery/Alt
switch depicted on Z-11 to the field terminal of the alternator with a fuse (5A?)
in between. Please advise if I am in error.
Also, I gather from recent bandwidth that during normal operation, one should avoid
switching the alternator off until the engine has shut down as this may be
unhealthy for Van's alternator (or perhaps all alternators?).
I know from flying Cessnas that occasionally the alternator will trip out and can
be brought back on line via cycling of the alt switch. Will that scenario
apply in your Z-11 schematic with an internally regulated alternator?
TIA for your help.
Joel Haynes
Bozeman, MT
________________________________________________________________________________
| From: | Charlie England <ceengland(at)bellsouth.net> |
| Subject: | Re: Audio Iso Amp problem |
Fiveonepw(at)aol.com wrote:
>
>Bob-
>
>My kit-built amp exhibits poor audio input from my Microair 760- the audio is
>"clipped?" where perhaps 1/3 of the signal gets through resulting in barely
>audible reception. By "clipped" I mean it is like I will hear perhaps 100 msec
>of audio with about 200 msec silence between. (WAG at time intervals) The
>audio alarm from my EIS4000 engine monitor sounds perfect, however- a nice
>clean "beep" simultaneously with the alarm light. I changed the 150 ohm input
>resistors with 180s with no noticeable difference.
>
>It is the same unit I sent you for testing some time ago and you reported it
>was fine. Autocad dwg of audio system available if desired. Suggestions?
>
>Thanks- Mark Phillips
>
You might check with an ohm meter from each input terminal on the amp to
ground (with everything still hooked up but not powered up). The
behavior of the 760 sounds like a current limiting circuit in an audio
output stage might be trying to protect it from overload. I don't have
the schematic in front of me but would expect to see at least 200 ohms
from input to ground on each input.
Charlie
________________________________________________________________________________
| From: | "Johnson, Phillip (EXP)" <phillip.johnson(at)lmco.com> |
| Subject: | Re: The fatwire ground blues . . . |
The problem of poor grounding whilst cranking the engine has always been a concern
of mine. To overcome this I have the battery ground connected directly to
the engine and then all grounds connect to the engine. This way no cranking current
flows through the sensor grounds under any conditions.
Phillip Johnson
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> challenged |
| Subject: | Re: Z-11 question for the electrically |
challenged
>
>Bob,
>I will shortly be wiring my RV-7a according to your Z-11 schematic and
>will be using Van's internally regulated 60 amp alternator. If I choose
>not to employ OV protection, I assume that I simply connect terminal #4 of
>the Battery/Alt switch depicted on Z-11 to the field terminal of the
>alternator with a fuse (5A?) in between. Please advise if I am in error.
I wish I had some good data to offer you.
As you may have gathered from much of the discussion
concerning internally regulated alternators here
on the List, the internally regulated alternator
as a class of product is a moving target.
First, there is no fixed protocol under which these
alternators respond to the command signal that comes
in the back on the small wire. Some alternators, I'm
told, will turn ON and OFF in response to bus voltage
supplied to the command input. Others will only turn
ON and are not controllable from the panel switch
after energized for the first time.
Second, in spite of exemplary demonstrations of reliability
in the automotive world (I've NEVER experienced an
OV event at any time in 40+ years of driving) we know
that numbers of our brethren HAVE experienced OV events
in internally regulated machines with various outcomes.
As a systems designer, I've taken the position that
my recommendations should be crafted for the most universal
application. I KNOW that 99% of all externally regulated
alternators will run well with 90% of all alternator
regulator products. I KNOW that removing field
excitation from and operating alternator will shut it
off. I KNOW there are useful techniques for sensing
over voltage and removing field excitation. Therefore,
combinations of externally regulated alternator, a regulator,
an OV protection system -AND- ACTIVE NOTIFICATION OF LOW
VOLTAGE offers a high degree of risk reduction
against catastrophic failures that propagate throughout the
system.
>Also, I gather from recent bandwidth that during normal operation, one
>should avoid switching the alternator off until the engine has shut down
>as this may be unhealthy for Van's alternator (or perhaps all alternators?).
Assuming that the alternator Van supplies will respond
to both ON and OFF commands, there is no risk for turning
the alternator ON or OFF while operating.
When we went conducted the exercise of trying to make
and automotive alternator look and behave like an
aircraft alternator, we discovered some unhappy
tradeoffs. Adding a b-lead contactor to assure positive
control of ANY internally regulated alternator, we
created a possibility of killing an perfectly good
working alternator by turning it OFF while loaded.
The risk of this happening goes away when we abandoned
the technique for exercising full control over the
alternator. At the same time, we lost the ability
to exercise protection against OV runaway.
>I know from flying Cessnas that occasionally the alternator will trip out
>and can be brought back on line via cycling of the alt switch. Will that
>scenario apply in your Z-11 schematic with an internally regulated alternator?
If you install Van's alternator per his recommendations,
there will be no OV protection to trip out. Therefore,
no reason to "reset" it by exercising the alternator control
switch.
I have no test data or narrative of an experiment
that defines how Van's alternator works. Perhaps someone
on the list is flying with Van's alternator who
can enlighten us.
Further, I have no knowledge of Van's configuration
management on alternators he sells. Its possible that
one batch of alternators may be fully controllable while
the next batch is Turn-On only.
Lack of data makes it impossible for one to
offer considered critical review of the system or to
suggest system integration or operational techniques.
Sorry I can't be more helpful at the moment.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: The fatwire ground blues . . . |
>
>
>The problem of poor grounding whilst cranking the engine has always been a
>concern of mine. To overcome this I have the battery ground connected
>directly to the engine and then all grounds connect to the engine. This
>way no cranking current flows through the sensor grounds under any conditions.
The only way one gets cranking current to flow in undesired
pathways is when desired pathways coexist with undesired
pathways. The ideal ground system eliminates parallel
pathways so that ANY open connection produces a passive
failure.
Sensors that ground to their mounting on the engine
should not be fitted with a second ground path. Most
suppliers of such sensors suggest a means for isolating
the sensor from engine case ground -or- they call for
the instrument that reads the sensor to ground to the
engine instead of behind the panel.
This is good practice BOTH for signal integrity by
elimination of ground loops and system safety against
burning bitty wires when big wires get unhooked.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Audio Iso Amp problem (corrected) |
>
>Bob-
>
>My kit-built amp exhibits poor audio input from my Microair 760- the audio is
>"clipped?" where perhaps 1/3 of the signal gets through resulting in barely
>audible reception. By "clipped" I mean it is like I will hear perhaps 100
>msec
>of audio with about 200 msec silence between. (WAG at time intervals) The
>audio alarm from my EIS4000 engine monitor sounds perfect, however- a nice
>clean "beep" simultaneously with the alarm light. I changed the 150 ohm
>input resistors with 180s with no noticeable difference.
>
>It is the same unit I sent you for testing some time ago and you reported it
>was fine. Autocad dwg of audio system available if desired. Suggestions?
Any changes to the series input resistors should be made in 2x/0.5x (was
1x/0.5x) steps.
For example, if you want to reduce gain of any one channel, the MINIMUM
useful increase would be from 150 to 300 ohms. If still too hot, go to
600 ohms, etc.
By the same token, if you need more gain, reduce a 150 ohm resistor
to 75 ohms first, then 36 ohms.
I'm hearing that some radios like to be "loaded" heavier on their
phones output signals than what the amplifier provides. Before you
change the 180 to anything else, try putting anything from 50 to
100 ohms ACROSS the Microair 760's headphones output leads.
What your describing sounds more like some kind of bias shift
than overloading. The "dummy" load may help more than anything
else. Let us know what you find.
I've had some good feedback from about a dozen builders of the
audio isolation amplifier with some suggestions for improvements.
I'm considering a second generation version . . . but to fit in
the same package, we'll have to go surface mounted parts which
is probably more than most builders want to tackle. If we do
it, the amplifier will offered as a plug-n-play assembly.
There's one going into a certified ship under a 337 installed
by what appears to be a really savvy technician. I asked him
to feed back impressions and suggestions too. I think this
gizmo is ripe for an upgrade but there's no reason we can't
make it do what you need done.
Bob . . .
--
-- incoming mail is certified Virus Free.
Bob . . .
--------------------------------------------------------
< Throughout history, poverty is the normal condition >
< of man. Advances which permit this norm to be >
< exceeded -- here and there, now and then -- are the >
< work of an extremely small minority, frequently >
< despised, often condemned, and almost always opposed >
< by all right-thinking people. Whenever this tiny >
< minority is kept from creating, or (as sometimes >
< happens) is driven out of a society, the people >
< then slip back into abject poverty. >
< >
< This is known as "bad luck". >
< -Lazarus Long- >
<------------------------------------------------------>
http://www.aeroelectric.com
________________________________________________________________________________
| From: | Joseph Larson <jpl(at)showpage.org> |
| Subject: | Re: The fatwire ground blues . . . |
Bob, your response below sounds very important. Up until your last
sentence, I was thinking, "What's wrong with a few extra grounds?
They should all be at the same potential, so it seems like extra
insurance." Then you mentioned the part about bitty wires taking
loads they can't handle, and suddenly most of the rest makes sense.
In other words, every device should have exactly one path IN for
power and exactly one path OUT back to the battery. Is that what
you're saying? This is how you can properly size the wires used,
because the ground for one device won't inadvertently be used as
ground for another device, resulting in an overloaded wire.
Can you explain what a ground loop is and provide an example of how
one creates one, so I can get a better feel for what to avoid?
Is it okay to "chain" a the ground of a bunch of devices together
before bringing them all to the battery?
-Joe
On Aug 4, 2005, at 8:47 AM, Robert L. Nuckolls, III wrote:
>
> The only way one gets cranking current to flow in undesired
> pathways is when desired pathways coexist with undesired
> pathways. The ideal ground system eliminates parallel
> pathways so that ANY open connection produces a passive
> failure.
>
> Sensors that ground to their mounting on the engine
> should not be fitted with a second ground path. Most
> suppliers of such sensors suggest a means for isolating
> the sensor from engine case ground -or- they call for
> the instrument that reads the sensor to ground to the
> engine instead of behind the panel.
>
> This is good practice BOTH for signal integrity by
> elimination of ground loops and system safety against
> burning bitty wires when big wires get unhooked.
________________________________________________________________________________
| Subject: | Re: Crowbar CB "problem" question |
My three cents worth-
Wired a Velocity with dual alternators using B & C's L-60, SD-20, LR3-14 and
SB1A-14.
We have 150 hours on the hobbs with these components with no overvoltage trips.
We did have the SD-20
fail a few weeks ago and it was promptly replaced by the company. Goog folks!
Peter
On 3 Aug 2005 at 16:15, bakerocb(at)cox.net wrote:
>
> AeroElectric-List message previously posted by: Richard Riley
>
>
> < particularly one of the B&C regulators - how often do the nuisance
> trips occur?
>
> If we're worried about the nuisance trips degrading field CB's, would
> it be a reasonable fix to replace those CBs at annual?>>
>
> 8/3/2005
>
> Hello Richard, 100 hours plus on my plane with an externally regulated
> (B&C), gear driven, 60 AMP alternator with no nuisance trips.
>
> Replacing CB's can be a bitch because frequently they are fastened 2
> or 3 or more to a brass bar. It can take a significant amount of
> unfastening and then reassembling to replace one CB.
>
> OC
>
>
>
>
>
>
>
________________________________________________________________________________
| From: | Fiveonepw(at)AOL.COM |
| Subject: | Audio Iso Amp Problem |
Bob-
You wrote:
=A0=A0 I'm hearing that some radios like to be "loaded" heavier on their
=A0=A0 phones output signals than what the amplifier provides. Before you
=A0=A0 change the 180 to anything else, try putting anything from 50 to
=A0=A0 100 ohms ACROSS the Microair 760's headphones output leads.
I notice in the latest Iso Amp dwgs a Failsafe Headset (and mic) Jack added-
my installation precedes this and I would like to incorporate the feature.
Would adding the load resistor you mention above between the ring and tip
terminals on the new headset jack be appropriate to the task?
In addition, installing the Failsafe Headset Jack and using a male phone plug
with a small value pot wired to its terminals would allow "fine tuning" the
appropriate resistance prior to installing the resistor?
These jacks would also require insulation from airframe as well, I surmise...
Thanks again-
Mark Phillips -6A
________________________________________________________________________________
| From: | "LarryRobertHelming" <lhelming(at)sigecom.net> |
| Subject: | Re: Crowbar CB "problem" question |
I have the B&C LR3 regulator with Vans 30 amp externally controlled
alternator. Wired per Bob's manual. No trips with 52 hours on the meter.
Indiana Larry, RV7 Tip Up It Flies
Teamwork: " A lot of people doing exactly what I say."
(Marketing exec., Citrix Corp.)
----- Original Message -----
From: "Richard Riley" <richard(at)RILEY.NET>
Subject: Re: AeroElectric-List: Crowbar CB "problem" question
>
> For those that have experience with an external regulator -
> particularly one of the B&C regulators - how often do the nuisance trips
> occur?
>
> If we're worried about the nuisance trips degrading field CB's, would
> it be a reasonable fix to replace those CBs at annual?
>
>
>
________________________________________________________________________________
| From: | gert <gert.v(at)sbcglobal.net> |
| Subject: | B&C website problems |
hmmm
no link anymore from 'lectric Bob's website to B&C ???
B&C website, giving me errors when linking to products???
something going on??
--
is subject to a download and archival fee in the amount of $500
________________________________________________________________________________
| Subject: | Re: B&C website problems |
Try http://www.bandcspecialty.com/
Peter
On 4 Aug 2005 at 15:48, gert wrote:
>
> hmmm
>
> no link anymore from 'lectric Bob's website to B&C ???
>
> B&C website, giving me errors when linking to products???
>
> something going on??
>
> --
>
>
> is subject to a download and archival fee in the amount of $500
>
>
>
>
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: B&C website problems |
>
>hmmm
>
>no link anymore from 'lectric Bob's website to B&C ???
>
>B&C website, giving me errors when linking to products???
>
>something going on??
We removed the link in preparation for some major changes
coming to our website which will include some whippy new
products.
I've had a few "page not found" type errors when roaming
the B&C site. It wouldn't hurt to drop them a note when
you discover one.
Bob . . .
________________________________________________________________________________
| From: | <gmcjetpilot(at)yahoo.com> |
| Subject: | Re:Real data on OVP/etc (disinterested?) |
>
>
>George: The alternator that failed was a Nippon Denso, 60 amp,
>internally regulated. I'm not sure that my experience should cause
>others to avoid this unit. I know that hundreds of airplanes are flying
>successfully with them. However, if you read Bob's most recent post,
>you might decide to avoid all internal regulated alternators.
>
Hi Jack:
> "Jack Eckdahl" wrote:
>However, if you read Bob's most recent post, you might decide to avoid all internal
>regulated alternators.
No Sir, I still think internally regulated alternators (ND in particular) are a
fine choice, without an adding on an OV protection device (crow bar). By fine
choice I mean safe & reliable. It is lighter, cheaper, simpler and less expensive
than an external regulated alternator. There is nothing wrong with a crow
bar, not with standing the little technical minutiae.
I have a great respect for Bob's opinions, which are based on his knowledge, experience,
standard aerospace practices and certification regulations, which is
all-good.
To make an analogy: Lets make a stew by cooking-up several pounds of knowledge
& experience. Than add an ounce of spice called opinion. The whole flavor of the
stew is influence and changed by that opinion. The taste is still good, but
it's a different flavored stew than if you used a different spice (opinion).
That does not mean a stew with another spice (opinion) is bad.
Bob has strong opinions, and is the guru of electrons who gives out design advice
thru this forum, seminars and his book. He has to believe and understand the
info he gives out. I don't blame him for not supporting IR alternators. He
does not have detailed info on the design or can he control it. However that does
not make IR alternators a poor choice or dangerous. In fact it is superior
in many ways to the method of DC power generation Bob campaigns. Bob does not
talk to the advantages of the IR alternator, but to be fair he does not say it
is bad. He just cant recommend it, and given the choices he must pick one idea
and back-up that one idea he feels is best overall for most applications. Thats
OK.
Pick your spice, make your stew, eat and enjoy. If you get indigestion it is your
own fault. I don't criticize other Cooks for using curry spice.
Bob says a crow bar and external VR is the best way to go; he has good reasons
to recommend it; he is comfortable with it. He knows how it works or should work.
Bob is not comfortable with IR regulators because he can't control the field
directly, in other words he does not trust the IC chip and the one field driver
transistor. Plus he has always used external voltage regulators at work.
Fair enough.
I do trust the IC chip and drive transistor. Why? They are proven in millions of
cars, trucks and industrial equipment, including a good lot of kit planes as
well. You can't get the FAA to certify an alternator on this basis, but again
who cares if you have a kit plane.
The electronic and auto industry has studied and tested these electronic components,
like the ones inside a ND alternator, i.e., transistors and IC circuits.
They have a known failure time in the millions of hours.
The big hang up with Bob and others is the one drive transistor (external to the
IC) could short out and by-pass the IC chips control of the alternator. How
likely is this? The chance is slim to none, and is proven every day when millions
of these alternators work with out fail, day after day, year after year, 100s
and 1,000s of hours every year.
I think a ND alternator with IR, without an added on crow bar, has the right spices
for my stew (electrical system) and is delicious.
Bob bases his design philosophy in part on a thought process of "how could you
certify this?" Well if you have an experimental you don't care or need a certified
accessory. I agree an IR alternator is hard if not impossible to certify
with the FAA as is, without spending mega dollars doing it. So the inertia of
the industry is to stay with what you know, externally regulated alternators.
You can't certify an accessory based on field service history in cars and kit
planes alone, but it sure speaks to its reliability. Good enough for me and many
other builders.
Bob works in the certified field; this is his line of work and influences his opinion.
Not that there is anything wrong with that. However if you think FAA certified
makes something better, you might consider a 1950's Delco or Ford Prestolite
automotive generator and mechanical points voltage regulator are FAA certified
on aircraft! Is that better than a small light Denso alternator with
IR? Bob's crow bar is not certified. B&C alternators & regulators are not certified.
Does that make them bad? NO. There is no magic to FAA certification. We
have the freedom to use Denso alternators in our kit planes, an in my opinion
we should exercise that option, not that Bob's baseline system is bad. I just
don't think it automatically should be the De facto design. No disrespect to
Bob, and sorry if that offends anyone.
Why has Bob's crow bar experienced premature trips? Stuff happens. I read about
the capacitor fix and understand why it helped. It seems to me, as an electronics
amateur, whenever you have transient conditions (dv/dt), throw a good old
capacitor in the mix. It always seems to mellow a circuit out. (mellow - a non-technical
term for filter to dampen transient voltage spikes.) When in doubt
put a capacitor in. (kidding)
There is never a 100% guarantee any device, including a simple crow bar or a ND
alternator will always work as designed. Simple things like a crow bar & circuit
breaker should work as Bob would point out. The same applies to Denso alternators.
However the idea propagated that a Denso failure means a colossal OV
condition is not valid. The usual Denso failure mode is passive, by just dying.
People want a 100% guarantees about everything in life and what they put on their
aircraft. Keep it simple; consider a stand alone Denso as an elegant simple
solution. Consider that crow bar could fail passively and not work when needed
without the pilot being aware of it. Bob said this is unlikely. BINGO. I agree
a simple crow bar should work, with emphasis on should. Same with a Denso alternator,
it is unlikely you will have an OV condition. At least the ND alternator
has a built in fault light (which will indicate many faults). Nothing is
perfect. Take a chance on life
> "Jack Eckdahl" wrote:
>George: The alternator that failed was a Nippon Denso, 60 amp, internally regulated.
Jack: I recall under peculiar conditions you observed your ND alternator going
to 16 volts. Also with the ALT switched off it produced power after starting the
engine. The technique of turning the alternator on after start was your normal
procedure. Obviously something was different than before, since it always
worked well and would not make power until switching it on. You also noted that
voltage varied 13 to 16 with load. By using a normal procedure of manually switching
the alternator ON after starting and OFF before shut down, you forced
an abrupt ON/OFF thru the regulator. This is known to cause grief. (Read below-The
IC chip inside the alternator is a microprocessor and its internal protections
only work if it is powered during engine start and stop.)
I recall pointing out sources for brand new 60 amp ND alternators to you. Not sure
what you ended up doing but assume you are flying around FHD with your new
ND alternator. My prediction is if you stop the practice of switching the alternator
ON/OFF manually and get a NEW 60 amp ND alternator, you will have a lifetime
of trouble free alternator service (with out crow bar). Odds are in your
favor. The only other recommendation I have is add a cooling blast tube to the
rear of the alternator, and avoid continuous operations above +30 amps. Heat
is the killer of semi-conductors.
ND alternators have an IC chip that provides many safety and fault protection functions
including OV protection. In fact this microprocessor chip may have thousands
of transistors VS. a Plain-Jane external VR with 2 or 4 transistors.
Therefore doing abrupt things repeatedly stresses the chip overtime. It just was
not designed to be used like that. You got away with it for a while, but eventually
is started to fail (with out dramatic affect I might add).
The IC chip also provides soft starts and load dump protection. SOFT START means
a large demand will not cause the alternator to instantaneously slam full open
but will ramp up to avoid a voltage overshoot. LOAD DUMP protection, keeps
voltage variation to a min with a large drop in load. When I say load dump I don't
mean dropping the B-lead abruptly with an OV relay, I mean turning the landing
lights OFF. I would like to see a two-transistor external voltage regulator
do this. The typical IR is more advanced than the typical ER.
Paul's http://www.periheliondesign.com/suppressors.htm may solve the problem of killing a healthy ND alternators when a nuisance trip of a B-lead OV relay opening while the alternator is under load. Who knows, it can't hurt. However my electrical system design philosophy (the stew I am cooking) is to keep it simple. I assume the chance of my alternator going into a real out-O-control OV condition from a drive transistor short is so small I accept. Just like I accept my single engine will continue to turn and my single wing spar will not fail in flight. (Sometimes these also fail, but we maintain them and fly within limits to assure they get us back on the ground safely.)
There has been much rhetoric about the dangers of IR alternators and the evil of
that one field drive transistor. The theory is the transistor failure inside
the IR bypasses the OV protection of the IC chip. This in turn causes the mother
of all OV conditions. Not to beat the horse to death (which is a bloody caucus
being picked at by vultures at this point), but this scenario is a theory
NOT born out by the proven reliability in service. No car or kit plane I know
of has ever had this condition from my research. I looked high and low and found
nothing, nada, zip, zero. I am not saying it has never happened or cant happen
(it can in theory), but there is no proof or documentation it has. If we
are going to get scientifically rigorous, than we need the data, otherwise it
is ignorant, to use Bobs words.
Show me any cases of a ND alternator having a real honest to goodness (documented)
shorted field drive transistor resulting in an over-voltage condition, urban
legend aside. Sporadic OV module problems are much more prolific than the non-existent
alleged alternator run-a-way.
The voltage problem (16 volts) you had was far from a wild run-a-way. Voltage Run-a-way
elicits thoughts of a train going down the mountain with no brakes, terror,
panic, destruction and emotion. That is why when you tie the BAT master
and ALT together, so the alternator is turned on automatically (i.e., DPST switch).
If you need to shut the ALT down, manually pull the CB.
> "Jack Eckdahl" wrote:
>I'm not sure that my experience should cause others to avoid this unit.
In my opinion using a ND alternator as is, provides an acceptable risk while gaining
a lighter, simpler and cost effective electrical power source. Everything
in aviation has risk, and the outcome depends on how you manage these risks.
Bob says that crow bar failure is not likely. BINGO!! I am saying run-a-way
voltage in a ND alternator is not likely. Again my opinion aside, facts like the
field service history of ND alternators indicate their IR alternator are pretty
darn good. I dont think the Japanese ND engineers that designed these devices
are ignorant. (The auto industry is very aware of OV and has lots of electronics
to protect.)
Jack: If you replaced your rebuilt alternator with a new one, assuming you have
stopped flipping the alternator ON an OFF manually, you will be fine. The BAT
master should turn the ALT on simultaneously (i.e., DPST switch). If you need
to disable the alternator pull the CB.
> "Jack Eckdahl" wrote:
>I know that hundreds of airplanes are flying successfully with them.
I have no idea about aftermarket rebuilds or second tier replacement parts VS.
OEM parts from ND. ND alternators can be bought new easily at discounted price
if you shop around. The medium frame 60 amp ND's are more readily available as
a rebuild, but they can be bought new if you look.
Compare the price of a B&C and an over the counter stock 60 amp ND alternator.
The whole B&C kit $820: alternator, regulator and brackets. If you buy a New ND
alternator ($180 retail, $120 discounted), brackets and parts (approx $40-$60),
your cost is about $250, the cost of Vans 60 amp ND alternator kit (with a
rebuilt alternator). The B&C cost 3 to 4 times more. Is it worth the cost? It
all depends on you opinion. Nothing wrong with spending the money but dont expect
100% reliability from the B&C, even on a dark and stormy night. Despite the
B&C advertisements, balanced rotor and all, there is no proof, data or facts
that the B&C system will achieve superior reliability over the stock ND alternator.
However if you are talking about reliability of a B&C or Stock ND alternator set-up
against certified 1950 and 60s technology factory aircraft electrical systems,
than yes, they are both way more reliable than the old certified stuff.
Now in theory may be B&C is better, but it cant be proven. The reason it cant be
proven is the data or statistics are not available. The reason for that is no
one is tracking it. Does B&C contact all customers with a service bulletin when
a problem is found? That would be nice. If you point to a ND alternator problem,
like the one above, than you can point to several B&C problems.
>Robert L. Nuckolls, III Wrote:
>Which only illustrates the ignorance of our customers promulgated by your rhetoric
and Van's equally ignorant advice.
Bob: I like to think they we have a different opinion not ignorant.
Quote: (snip) ignorance of our customers (snip) and Vans equally ignorant advice.
You just called everyone ignorant Bob. With all due respect that sounds condescending
and insulting. May be you meant something else, but I take umbrage to that.
No one likes to be called ignorant. Do you talk to Van.
I think your crow bar is great as a simple cheap solution to protecting alternators
with external regulators, which need protection, but not on IR alternators,
which is designed to work without any other OV protection.
Van recommends NOT installing an OV module on the 60amp ND alternator, because
it can and does cause damage to them. Bob's comment and use of the word *ignorance*
in describing Van's and Paul's opinion is dogmatic.
I don't know Van personally but I have met him and talked to him several times
over the last 15 years, building two of his kits. He is a very smart conservative
guy, and has a degree in engineering, as I do. From Van's stand point ND alternators
have been damaged with crow bar trips. Why did Bob call the man ignorant?
Whether intentional or accidental, a crow bar trip can damage an ND alternator.
This fact is bore out by the induced failure Jack had, described above.
We dont know what data Van is working on. The man after all has over 4200 planes
flying of his design and been in the kit plane market for 30 years, which gives
him a little creditability. To call his opinion or Paul's opinion ignorant
is not sensible. Everyone has the best intention here, and their suggestions
are safe and reasonable in my opinion, whether you or I agree or not.
I agree with Vans opinion that you should NOT use an OV module with an IR alternator,
but I also agree with Bob. If you feel that you cannot rely on an IR and
it's on-board OV protection than go with a crow-bar-ed external VR alternator.
An external VR adds complexity, wiring, cost and weight and scheduled maintenance
and testing, but it works.
I can accept the IR and the minimal risk alleged that there is a statistical possibility,
albeit unlikely, the field driver transistor can short. My decision
to use an IR alternator and no crow bar gives me a light, simple, compact, cheaper
system requiring no maintenance and testing. Plus parts are available nationwide
over the counter at thousands of auto part stores and auto electric shops.
Of course a NEW alternator is better than an overhauled one, but on a trip
if you did have a problem, you could buy one across the street from the airport
at Auto-parts-R-us, with a warranty. My old home airport had a large import
auto salvage yard with in walking distance from my hanger.
Therefore Van's advice is not ignorant or Pauls flavor of opinion less valid than
Bob's, technical minutia aside. Bob can't guarantee the crow bar will never
have a false trip or fail passively. He can't do it. Go ahead and say unlikely,
but never say never. Like wise, Nippon Denso can't guarantee a high voltage
failure, but ND engineers do know about OV. They understand OV and designed their
product to minimize the chance of it happening. From the field service history
in cars and experimental planes, ND did a great job. There are other alternator
brands, some better than others, but in my opinion the ND is probably
the best.
The ND alternator with an IR is designed as a stand-alone unit. The interaction
of and value of an OV module (crow bar) with an IR alternator is of dubious value.
If the OV module can never false trip, than you will never damage the alternator.
However that is not how it works in the real world. If Paul's B-lead
suppressor works than that might be an option, allowing a safer way to incorporate
a crow bar type device (Bob's or Paul's) safely on a ND alternator.
Adding a crow bar to an IR alternator is really an effort in belt and suspenders.
If you try to have your cake and eat-it to, you may end up with the worst of
both worlds. Dont mix and match systems. (Too much spice in one stew is bad.)
Accept the fact what ever you do, when you fly a plane, especially one you build
with systems you designed, you are risking life and limb NO MATTER WHAT YOU
DO. A single pilot in a single engine airplane is more risky than driving a car
crazy folks behind the wheel sharing the same road. I firmly believe you can
beat the General Aviation odds, but that might mean more pilot training, not
more electrical gadgets. The pilot is the most dangerous thing in the plane, not
the voltage regulator. Build your plane to fly with out it.
I think it is fair to disagree, right? I say go with an IR alternator with no extra
OV protection. My best advice is design your systems as simple as possible,
while still getting the job done. Have a back-up, but be reasonable.
Cheers George
---------------------------------
Stay connected, organized, and protected. Take the tour
________________________________________________________________________________
| From: | gert <gert.v(at)sbcglobal.net> |
| Subject: | Re: B&C website problems |
did just that, sent them an emial with specifics, actually the whole
relay page seems to be fubar.
Robert L. Nuckolls, III wrote:
>
>
>
>
>>
>>hmmm
>>
>>no link anymore from 'lectric Bob's website to B&C ???
>>
>>B&C website, giving me errors when linking to products???
>>
>>something going on??
>>
>>
>
> We removed the link in preparation for some major changes
> coming to our website which will include some whippy new
> products.
>
> I've had a few "page not found" type errors when roaming
> the B&C site. It wouldn't hurt to drop them a note when
> you discover one.
>
> Bob . . .
>
>
>
>
--
is subject to a download and archival fee in the amount of $500
________________________________________________________________________________
| From: | "Malcolm Thomson" <mthomson(at)showmeproductions.com> |
| Subject: | Screw terminals and Vision Microsystems' 1000 |
0.03 HTML_TEXT_AFTER_HTML BODY: HTML contains text after HTML close tag
0.06 HTML_TEXT_AFTER_BODY BODY: HTML contains text after BODY close tag
We are having reliability issues with a VMS 1000. Intermittent gauge
readings, reboots, etc. I believe the issue is the connections to the unit
which are made with screw terminals. These are the kind of terminals in
which you strip the wire, insert it into the hole and then tighten the screw
onto the wire. Does anyone have a suggestion of how this type of connection
can be turned into something more reliable. Have others had this issue with
the VMS 1000 or is it just me?
Thanks.
--
________________________________________________________________________________
| Subject: | Electric Tail wheel tug |
| From: | Gary Graham <beeb(at)pcez.com> |
Salvage Co.: C&H Sales. California.
www.candhsales.com They have wheel chair motors and gear box etc. New and
used
Order a catalog A good read for the inventor
Pugsley the RV Dog
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> Microsystems' 1000 |
| Subject: | Re: Screw terminals and Vision |
Microsystems' 1000
>
>
>We are having reliability issues with a VMS 1000. Intermittent gauge
>readings, reboots, etc. I believe the issue is the connections to the unit
>which are made with screw terminals. These are the kind of terminals in
>which you strip the wire, insert it into the hole and then tighten the screw
>onto the wire. Does anyone have a suggestion of how this type of connection
>can be turned into something more reliable. Have others had this issue with
>the VMS 1000 or is it just me?
Funny thing about those terminal strips . . . Greg Richter
likes 'em too. See pages 41 and 50 of
http://www.aeroelectric.com/articles/richter/response_1.pdf
These terminal strips are one step above wrapping a wire
around a screw and mashing it under a washer. Not gas tight,
no insulation support.
I'm wondering if Greg uses these throughout is
EFIS system?
Anyhow, it does not surprise me that you or anyone else
might have some difficulties with them. They're not
very suited to a mobile environment, especially airplanes.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: The fatwire ground blues . . . |
>
>At 06:47 AM 8/4/2005, you wrote:
>
>...
> > The ideal ground system eliminates parallel
> > pathways so that ANY open connection produces a passive
> > failure.
>
>Bob,
> How would I test for parallel pathways? Could I simply disconnect
>the big ground braid and look for continuity between the firewall forest of
>tabs and the engine?
If you didn't install a parallel wired pathway, then it doesn't
need to be tested. In the case under discussion: In addition to
crankcase-to-ground-block fatwire, the system had a 22 or 20AWG ground wire
running from some case-grounded sensor on the engine to a ground
terminal on the instrument panel mounted display computer.
The fact that the sensor was ALREADY grounded to the engine made
the sensor groundwire a redundant parallel pathway that
burned when it tried to carry starter current through the
display when the fat-wire connection at the crankcase was
loose.
Just for grins, one COULD disconnect the fatwire from the
engine and measure resistance across the open gap. Under
ideal conditions, the measured value would be in kilo ohms.
Under worst case but acceptable conditions a reading of as
low as 100 ohms or so will be relatively risk free for
noise or burnt wire issues.
In the case cited above, the measurement would have been
under 2 ohms . . . an invitation for smoke.
Bob . . .
________________________________________________________________________________
| From: | "Steve Ruse" <steve(at)wotelectronics.com> |
| Subject: | Power/ground terminal blocks |
I'm looking for power & ground terminal blocks, and haven't been able to
find them anywhere. I'm not sure if that is the correct term for what I am
looking for or not. Basically I need a terminal block that will connect
multiple wires to one wire, instead of acting as a pass-through/disconnect
point for each wire. I want to mount them behind my panel, bring in one hot
wire and one ground, and then feed each individual device from that strip.
Make sense?
I know something like this exists, I'm surprised they aren't easier to find.
Can anyone tell me where to get these?
Thanks!
Steve Ruse
Dallas, TX
--
________________________________________________________________________________
| From: | "Bruce Gray" <Bruce(at)glasair.org> |
| Subject: | Screw terminals and Vision Microsystems' 1000 |
Upgrade to the VM1000C. They have gone to all d-sub connectors.
Bruce
www.glasair.org
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Malcolm
Thomson
Subject: AeroElectric-List: Screw terminals and Vision Microsystems' 1000
We are having reliability issues with a VMS 1000. Intermittent gauge
readings, reboots, etc. I believe the issue is the connections to the unit
which are made with screw terminals. These are the kind of terminals in
which you strip the wire, insert it into the hole and then tighten the screw
onto the wire. Does anyone have a suggestion of how this type of connection
can be turned into something more reliable. Have others had this issue with
the VMS 1000 or is it just me?
Thanks.
--
________________________________________________________________________________
| From: | Kevin Horton <khorton01(at)rogers.com> |
| Subject: | Re: Power/ground terminal blocks |
On 5 Aug 2005, at 24:12, Steve Ruse wrote:
>
>
> I'm looking for power & ground terminal blocks, and haven't been
> able to
> find them anywhere. I'm not sure if that is the correct term for
> what I am
> looking for or not. Basically I need a terminal block that will
> connect
> multiple wires to one wire, instead of acting as a pass-through/
> disconnect
> point for each wire. I want to mount them behind my panel, bring
> in one hot
> wire and one ground, and then feed each individual device from that
> strip.
> Make sense?
>
> I know something like this exists, I'm surprised they aren't easier
> to find.
> Can anyone tell me where to get these?
>
How are you going to protect each hot wire from a short? If you are
going to use CBs, then many people have a copper or brass bar that
connects one side of the CBs together to distribute the power to
them. If you want to use fuses, then you should look at some sort of
fuseblock. See http://www.steinair.com/fuseblocks.htm. Ones with
more fuses are available from B & C Specialties, but their site isn't
working properly right now. http://www.bandc.biz/parts.html I
recommend fuse blocks.
For grounds, B and C Specialties sells a brass tab block that is
designed to be used as a single point to ground dozens of things. It
has dozens of tabs to take Fast-On connectors that you crimp onto the
end of each wire. http://www.bandc.biz/parts.html
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
________________________________________________________________________________
| From: | Mickey Coggins <mick-matronics(at)rv8.ch> |
| Subject: | Re:Real data on OVP/etc (disinterested?) |
> By using a normal procedure of manually switching the alternator ON
> after starting and OFF before shut down, you forced an abrupt ON/OFF
> thru the regulator. This is known to cause grief. (Read below-The IC
> chip inside the alternator is a microprocessor and its internal
> protections only work if it is powered during engine start and stop.)
> ... ND alternators have an IC chip that provides many safety and
> fault protection functions including OV protection. In fact this
> microprocessor chip may have thousands of transistors VS. a
> Plain-Jane external VR with 2 or 4 transistors. Therefore doing
> abrupt things repeatedly stresses the chip overtime. It just was not
> designed to be used like that. You got away with it for a while, but
> eventually is started to fail (with out dramatic affect I might add).
>
I had not heard of this before. Are you saying that I should make
sure the alternator is on whenever the batteries are on?
--
Mickey Coggins
http://www.rv8.ch/
#82007 finishing
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Power/ground terminal blocks |
>
>
>I'm looking for power & ground terminal blocks, and haven't been able to
>find them anywhere. I'm not sure if that is the correct term for what I am
>looking for or not. Basically I need a terminal block that will connect
>multiple wires to one wire, instead of acting as a pass-through/disconnect
>point for each wire. I want to mount them behind my panel, bring in one hot
>wire and one ground, and then feed each individual device from that strip.
>Make sense?
>
>I know something like this exists, I'm surprised they aren't easier to find.
>Can anyone tell me where to get these?
How would you use such a device in the architecture of your
electrical system? Have you selected an architecture? May
I suggest that you review the document which you may download
at:
http://aeroelectric.com/articles/Rev11/AppZ_R11C.pdf
. . . pick an architecture that comes closest to what you
believe you'd like to have and then consider modifying it
as needed for any special requirements you might have. Then
toss those considerations out here on the List for considered
critical review. In particular, help us understand the
concepts you described in your posting above and where this
technique fits into any of the suggested architectures.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re:Real data on OVP/etc (disinterested?) |
> > By using a normal procedure of manually switching the alternator ON
> > after starting and OFF before shut down, you forced an abrupt ON/OFF
> > thru the regulator. This is known to cause grief.
Please cite the study and a location from which we might
access it . . .
> (Read below-The IC
> > chip inside the alternator is a microprocessor and its internal
> > protections only work if it is powered during engine start and stop.)
> > ... ND alternators have an IC chip that provides many safety and
> > fault protection functions including OV protection. In fact this
> > microprocessor chip may have thousands of transistors VS. a
> > Plain-Jane external VR with 2 or 4 transistors. Therefore doing
> > abrupt things repeatedly stresses the chip overtime. It just was not
> > designed to be used like that. You got away with it for a while, but
> > eventually is started to fail (with out dramatic affect I might add).
The users of microprocessors throughout the industrial world would
be astounded should suppliers of such devices express this kind
of warning in the specifications for their products. I will suggest
that any microprocessor product has no upper bounds for exercising
it's functionality if one observes the well stated limits to
external stress (voltages and currents) and accepts limit to
operational agility (clock speeds). The notion that any manufacturer
would field a product with the vulnerabilities cited above is
mind boggling.
Bob . . .
________________________________________________________________________________
| From: | "Dale Ensing" <densing(at)carolina.rr.com> |
| Subject: | Re: Screw terminals and Vision Microsystems' 1000 |
Simalar probems with RMI engine monitor......After 70 hours on the airplane
I am now starting to have fluctuating CHT and EGT gauge readings with the
RMI engine monitor. Engine is running normally. I also suspect the
connections between the sensor wires and hook-up wires to the instrument.as
it is happening on all but one cylinder. The connectors are the bullet
shaped push-ins and seem to be tight as it is very difficult to pull them
apart. I too would appreciate hearing from others if they have had this
problem and how they corrected it.
Dale Ensing
RV-6A
We are having reliability issues with a VMS 1000. Intermittent gauge
readings, reboots, etc. I believe the issue is the connections to the unit
which are made with screw terminals. These are the kind of terminals in
which you strip the wire, insert it into the hole and then tighten the screw
onto the wire. Does anyone have a suggestion of how this type of connection
can be turned into something more reliable. Have others had this issue with
the VMS 1000 or is it just me?
________________________________________________________________________________
| From: | "Wayne Sweet" <w_sweet(at)comcast.net> |
| Subject: | Re: Screw terminals and Vision Microsystems' 1000 |
I have had this same problem with my older Vision 800 system. One way to
make the connection more robust is to wrap the stripped wire back around the
insulation, say 1/8" and then insert that into the hole. Then the screw will
clamp down onto the wire supported by the insulation just prior to the
stripped section.
Wayne
----- Original Message -----
From: "Robert L. Nuckolls, III Microsystems' 1000" <nuckollsr(at)cox.net>
Subject: Re: AeroElectric-List: Screw terminals and Vision Microsystems'
1000
> Microsystems' 1000
>
>
>>
>>
>>We are having reliability issues with a VMS 1000. Intermittent gauge
>>readings, reboots, etc. I believe the issue is the connections to the
>>unit
>>which are made with screw terminals. These are the kind of terminals in
>>which you strip the wire, insert it into the hole and then tighten the
>>screw
>>onto the wire. Does anyone have a suggestion of how this type of
>>connection
>>can be turned into something more reliable. Have others had this issue
>>with
>>the VMS 1000 or is it just me?
>
> Funny thing about those terminal strips . . . Greg Richter
> likes 'em too. See pages 41 and 50 of
>
> http://www.aeroelectric.com/articles/richter/response_1.pdf
>
> These terminal strips are one step above wrapping a wire
> around a screw and mashing it under a washer. Not gas tight,
> no insulation support.
>
> I'm wondering if Greg uses these throughout is
> EFIS system?
>
> Anyhow, it does not surprise me that you or anyone else
> might have some difficulties with them. They're not
> very suited to a mobile environment, especially airplanes.
>
> Bob . . .
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | headset and microphone plugs |
0.01 URI_REDIRECTOR Message has HTTP redirector URI
>Longer form.
>
>I'm working on a panel mount intercom in an ultralight, trying to connect to
>an Icom radio. I believe I've got a problem in the superfine wires going to
>microphone and headset plugs. The previous builder connected those plugs to
>an Icom connector cable (jacks going to an Icom connector).
>
>One way out of my trouble would be to find connectors which let me solder
>"real" wire to. One is a 3/8 headphone style, the other is slightly smaller
>(0.205?) for the microphone. They're the same size plugs as an aviation
>headset uses. I can't seem to find these connectors sold in kit form.
>
>There may be other ways to solve this, but I'm almost ready to buy a
>"portable" intercom (which has the connectors already wired) and break the
>case to remount in my panel.
>
>I'd appreciate any leads on where to find connectors, or on alternate
>solutions.
The plugs your looking for are made by Switchcraft and
may be viewed at:
http://www.switchcraft.com/products/jack-122.html
#480 is for the microphone, #440 is for headset side.
You can purchase from folks linked below:
http://www.newark.com/NewarkWebCommerce/newark/en_US/endecaSearch/partDetail.jsp?SKU=39F792&CMP=AFC-CC3763909474&QTexthttp://www.onlinecomponents.com/search-general.cfm?pn=480&manufacturer=SWITCHCRAFT&ref=Froogle
and
http://www.newark.com/NewarkWebCommerce/newark/en_US/endecaSearch/partDetail.jsp?SKU=39F791&CMP=AFC-CC3763909474&QTexthttp://www.onlinecomponents.com/search-general.cfm?pn=480&manufacturer=SWITCHCRAFT&ref=Froogle
I note that the Newark description and illustration for the #480 is
wrong but the part number and price differential suggests that
if you order a #480, that you'll get the right part as described
in the Switchcraft data sheet cited above.
Bob . . .
________________________________________________________________________________
| From: | "Paul McAllister" <paul.mcallister(at)qia.net> |
| Subject: | Re: Screw terminals and Vision Microsystems' 1000 |
Hi all,
Although I don't know a good source, it is possible to purchase crimp pins
that will solve this problem. Good quality ones are constructed in a
similar manner as the push on spade connector, but have a pin instead that
can be put in the terminal block.
Paul
________________________________________________________________________________
| From: | Steve Ruse <steve(at)wotelectronics.com> |
| Subject: | Re: Power/ground terminal blocks |
Thanks for the input Bob. The fuseblock suggested by Kevin is exactly
what I'm
looking for. My system will be most similar to "Z-29". Just a very basic
battery-only system. My plane has no starter or alternator, although I
may add
a wind generator at some point in the future. I will only be powering my GPS,
Intercom, and COMM radio from a battery, via something like the
fuseblock Kevin
suggested. I will also provide a spare 12v jack, as well as a ground charging
jack.
Thanks for the input,
Steve Ruse
Dallas, TX
> How would you use such a device in the architecture of your
> electrical system? Have you selected an architecture? May
> I suggest that you review the document which you may download
> at:
>
> http://aeroelectric.com/articles/Rev11/AppZ_R11C.pdf
>
> . . . pick an architecture that comes closest to what you
> believe you'd like to have and then consider modifying it
> as needed for any special requirements you might have. Then
> toss those considerations out here on the List for considered
> critical review. In particular, help us understand the
> concepts you described in your posting above and where this
> technique fits into any of the suggested architectures.
>
> Bob . . .
________________________________________________________________________________
| From: | "Malcolm Thomson" <mthomson(at)showmeproductions.com> |
| Subject: | Screw terminals and Vision Microsystems' 1000 |
Thanks Paul. If anyone has a source or picture of what Paul is describing,
please let me know.
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Paul
McAllister
Subject: Re: AeroElectric-List: Screw terminals and Vision Microsystems'
1000
-->
Hi all,
Although I don't know a good source, it is possible to purchase crimp pins
that will solve this problem. Good quality ones are constructed in a
similar manner as the push on spade connector, but have a pin instead that
can be put in the terminal block.
Paul
--
--
________________________________________________________________________________
| From: | "Rhett Westerman" <Rhettwesterman(at)cox.net> |
| Subject: | Screw terminals and Vision Microsystems' 1000 |
Malcolm,
I have almost 1000 hours on my VM1000 and never any trouble. I have many
friends with this same unit that have run trouble free for long periods of
time.
I suspect that your wires are touching more than they are supposed to at the
DPU or you have trouble elsewhere in the wiring. I do not think it is the
screw terminals.
best,
Rhett
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of
Malcolm Thomson
Subject: AeroElectric-List: Screw terminals and Vision Microsystems'
1000
We are having reliability issues with a VMS 1000. Intermittent gauge
readings, reboots, etc. I believe the issue is the connections to the unit
which are made with screw terminals. These are the kind of terminals in
which you strip the wire, insert it into the hole and then tighten the screw
onto the wire. Does anyone have a suggestion of how this type of connection
can be turned into something more reliable. Have others had this issue with
the VMS 1000 or is it just me?
Thanks.
--
________________________________________________________________________________
| Subject: | Re: Screw terminals and Vision Microsystems' 1000 |
| From: | "John Schroeder" <jschroeder(at)perigee.net> |
Malcolm -
I have seen small, all-metal end caps that you crimp on to the ends of the
wires. The cap is then inserted into the terminal. I have not had to do
this because we do not have this kind of terminal in the A/C.
John
PS Are you flying the Thunder yet?
O
> We are having reliability issues with a VMS 1000. Intermittent gauge
> readings, reboots, etc. I believe the issue is the connections to the
> unit
> which are made with screw terminals. These are the kind of terminals in
> which you strip the wire, insert it into the hole and then tighten the
> screw
> onto the wire. Does anyone have a suggestion of how this type of
> connection
> can be turned into something more reliable.
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Aeroelectric List Format |
When the Federal government and IBM were struggling in court a decade ago, IBM's
defense strategy was to send truckloads of documents to the government prosecutors.
When the prosecutors asked for the slightest clarification on any point,
IBM would ask for a geological amount of time to answer the question, then
responded with more truckloads of documents. IBM kept this up until the government
simply gave up and went away.
This is to illustrate that all methods of argument are not equal, and some lead
nowhere. I suspect that this "public email list server" has its structural limits,
and we have exceeded them mightily.
So what to do....? I suspect that the Aeroelectric Connection (or its clone) should
be turned into a free document that can be edited continuously online like
Wikipedia or other open source documents. Although one could charge for the
subscription, the consensus seems to be that free subscriptions and paid advertising
works better.
Good textsbooks like the Aeroelectric Connection remain unread for the most part
since people absorb what they find of most interest at the moment. Books also
freeze a particular technical viewpoint, and the technology is changing too
fast for this to be the medium of choice.
The Aeroelectric list is handicapped by many operational limitations, such as no
graphics attachments, no video clips, short display times (seven days goes zooming
by), obscure formatting restrictions, etc.
The wonders of the internet allow magical connections between people. We aren't
doing it yet and as a result problems with discourse follow. The list is tiresomely
repetitive, running the same debates on and on, just because the medium
makes it so easy to forget all the arguments previously posted. I could suggest
just numbering the arguments like the old joke about the comedian convention.
Mr. X and Mr. Y lashing each other about load dump, "Well, that's old # XY-LD135Z.
I thought we resolved that....let's see....two years ago? Let's put on
our thinking caps (the beanie with the little propeller on it), and seek a better
answer.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
(508) 764-2072
"What the West really has to offer is honesty. Somehow, in the midst of their
horrid history, the best among the Gaijin learned a wonderful lesson. They
learned to distrust themselves, to doubt even what they were taught to believe
or what their egos make them yearn to see. To know that even truth must be
scrutinized, it was a great discovery...."
-- David Brin, "Dr. Pak's Preschool"
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re:Real data on OVP/etc (disinterested?) |
George you flatter me!
>Paul's http://www.periheliondesign.com/suppressors.htm
Should be Eric M. Jones's http://www.periheliondesign.com/suppressors.htm
I borrow good designs wherever I can find them.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
(508) 764-2072
________________________________________________________________________________
| From: | "Ron Raby" <ronr(at)advanceddesign.com> |
| Subject: | Re: Screw terminals and Vision Microsystems' 1000 |
Malcolm
They are called ferrules. Various manufactures. We use Weidmuller, for 22
awg the part # is 902575. There is a special crimper to put them on though.
www.weidmuller.com
Regards
Ron Raby
Lancair ES
55 hrs
----- Original Message -----
From: "John Schroeder" <jschroeder(at)perigee.net>
Subject: Re: AeroElectric-List: Screw terminals and Vision Microsystems'
1000
>
>
> Malcolm -
>
> I have seen small, all-metal end caps that you crimp on to the ends of the
> wires. The cap is then inserted into the terminal. I have not had to do
> this because we do not have this kind of terminal in the A/C.
>
> John
>
> PS Are you flying the Thunder yet?
>
>
> O
>> We are having reliability issues with a VMS 1000. Intermittent gauge
>> readings, reboots, etc. I believe the issue is the connections to the
>> unit
>> which are made with screw terminals. These are the kind of terminals in
>> which you strip the wire, insert it into the hole and then tighten the
>> screw
>> onto the wire. Does anyone have a suggestion of how this type of
>> connection
>> can be turned into something more reliable.
>
>
>
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
| Subject: | Screw terminals and Vision Microsystems' 1000 |
AeroElectric-List message previously posted by: "Malcolm Thomson"
<>
8/5/2005
Hello Malcolm, VMS has abandoned the screw terminals for connecting the
sensor wires to the DPU (Data Processing Unit) and gone to D Sub
connections. They did this just about the time my DPU was delivered with
screw terminals. I sent the DPU back to them and they converted it (Jan
2001) to the D Sub connector type, returned it to me, and it was installed
by me.
If you are absolutely convinced that the screw terminals are at fault it may
be possible for them to convert your DPU also. Be advised that this will not
be a trivial task. It will down your plane while the change to the DPU is
being made. It will cost money. You may have to rewire all of your sensors
since just putting D Sub connectors on your present wires may not be
feasible. Wiring up the D Sub connectors is quite a chore. If you want to
consider going this route contact me off list and I will mail you some
instructions from the current VMS manual that will give you an idea of what
is involved.
Let's consider something else -- is it possible that the problem lies in the
flat ribbon cable going to your gauges? These cables and the insulation
piercing connectors are not foolproof and they can go bad. You can purchase
cabling and connectors from the electrical supply places and roll your own
replacement (contact me for advice) or you can order a replacement cable
from VMS and install it. Ordering a cable from VMS is much easier of the two
choices.
Also tell us a little more about the reboot problem symptoms -- maybe there
is something to be learned from that. Power supply wire to DPU loose?
Voltage drops down during starting and the unit comes back whacky?
Or.......?
OC
PS: I would not hesitate to email support(at)visionmicrosystems.com or call
David McCluskey (360-714-8203) at VMS for help. I have the very highest
regard for the integrity and capability of the customer service of VMS. I
hope that their joining with JPI does not change that.
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re:Real data on OVP/etc (disinterested?) |
>
>
>George: The alternator that failed was a Nippon Denso, 60 amp,
>internally regulated. I'm not sure that my experience should cause
>others to avoid this unit. I know that hundreds of airplanes are flying
>successfully with them. However, if you read Bob's most recent post,
>you might decide to avoid all internal regulated alternators.
>
Hi Jack:
> "Jack Eckdahl" wrote:
>However, if you read Bob's most recent post, you might decide to avoid
all internal >regulated alternators.
No Sir, I still think internally regulated alternators (ND in particular)
are a fine choice, without an adding on an OV protection device (crow bar).
By fine choice I mean safe & reliable. It is lighter, cheaper, simpler and
less expensive than an external regulated alternator. There is nothing
wrong with a crow bar, not with standing the little technical minutiae.
I have a great respect for Bob's opinions, which are based on his
knowledge, experience, standard aerospace practices and certification
regulations, which is all-good.
To make an analogy: Lets make a stew by cooking-up several pounds of
knowledge & experience. Than add an ounce of spice called opinion. The
whole flavor of the stew is influence and changed by that opinion. The
taste is still good, but it's a different flavored stew than if you used a
different spice (opinion). That does not mean a stew with another spice
(opinion) is bad.
Bob has strong opinions, and is the guru of electrons who gives out design
advice thru this forum, seminars and his book. He has to believe and
understand the info he gives out. I don't blame him for not supporting IR
alternators. He does not have detailed info on the design or can he
control it. However that does not make IR alternators a poor choice or
dangerous.
It depends on your paradigm . . .
In fact it is superior in many ways to the method of DC power generation
Bob campaigns. Bob does not talk to the advantages of the IR alternator,
but to be fair he does not say it is bad. He just cant recommend it, and
given the choices he must pick one idea and back-up that one idea he feels
is best overall for most applications. Thats OK.
Pick your spice, make your stew, eat and enjoy. If you get indigestion it
is your own fault. I don't criticize other Cooks for using curry spice.
Bob says a crow bar and external VR is the best way to go; he has good
reasons to recommend it; he is comfortable with it. He knows how it works
or should work. Bob is not comfortable with IR regulators because he can't
control the field directly, in other words he does not trust the IC chip
and the one field driver transistor. Plus he has always used external
voltage regulators at work. Fair enough.
Which is not an opinion sir. Nor is it a preference for anyone's
stew. For the past 70+ years, folks flying airplanes have had
switches on the panel that offer (1) absolute control over all sources
of power in the aircraft and (2) has a remote probability of a failure
that propagates across multiple systems. The FAA requires that I
work within that paradigm when offering up new systems for certification.
I do trust the IC chip and drive transistor. Why? They are proven in
millions of cars, trucks and industrial equipment, including a good lot of
kit planes as well. You can't get the FAA to certify an alternator on this
basis, but again who cares if you have a kit plane.
I'm completely mystified by this statement. How does the fact that
the FAA will or will not bless any particular reasoning make it
an automatic no-brainer for someone building his own airplane?
This isn't about regulations or opinions, it's about design goals
that satisfy the paradigm under which the owner/operator of the
end product. 99+ percent of OBAM airplane builders are comfortable
with and most understand the paradigm that controls how certified
airplanes operate.
Do you have data about how the various IR alternators operate such
that you can DEMONSTRATE that anything with ND's name on it will
operate in the paradigm that applies to the vast majority of airplanes
flying? If not, then your recommendation is not backed up by
demonstrable and consistent performance characteristics and is,
in fact, purely a preference for a different taste in your
bowl of stew.
Now, we can come forward with any number of new ideas. The e-bus
was launched from the pages of the AeroElectric Connection over a
dozen years ago. I sincerely hope that folks are taking advantage of
this new paradigm no because you or I had any opinions about it.
I hope builders incorporate this feature because they
understand and appreciate its value. It's my job to instill
understanding, not to convince anyone of anything.
The electronic and auto industry has studied and tested these electronic
components, like the ones inside a ND alternator, i.e., transistors and IC
circuits. They have a known failure time in the millions of hours.
No argument there. None-the-less, folks continue to
come forward with their failure experiences. Not a "current
generation ND alternator? Don't know. Not a stock
regulator? Don't know. Would a well considered ov
protection system of ANY flavor have saved the day?
Probably . . . likelihood of dual failures in same
system on same flight are extremely rare. At least
one customer with the b-lead contactor and OVM-14
crowbar module has written to me expressing relief
that the system was in place when his IR alternator
went tits up.
The big hang up with Bob and others is the one drive transistor (external
to the IC) could short out and by-pass the IC chips control of the
alternator. How likely is this? The chance is slim to none, and is proven
every day when millions of these alternators work with out fail, day after
day, year after year, 100s and 1,000s of hours every year.
But do you agree that the risk is not zero? In fact,
one of our brothers here on the list reported such an
incident recently. If I were trying to convince someone
of anything, I could have wished that Jack's failure would
have occurred two hours out, at night, over mountains
and took out a bunch of radios to boot. When one is looking
for propaganda fodder, the sweat-drenched, nail-biting
stories are much more useful. Gee Jack, you let us down.
I think a ND alternator with IR, without an added on crow bar, has the
right spices for my stew (electrical system) and is delicious.
Please consume it in good health.
Bob bases his design philosophy in part on a thought process of "how could
you certify this?" Well if you have an experimental you don't care or need
a certified accessory. I agree an IR alternator is hard if not impossible
to certify with the FAA as is, without spending mega dollars doing it. So
the inertia of the industry is to stay with what you know, externally
regulated alternators. You can't certify an accessory based on field
service history in cars and kit planes alone, but it sure speaks to its
reliability. Good enough for me and many other builders.
You absolutely missed the point. Again, this has nothing
to do with how much this system would please or displease
me, the FAA or anyone else. It has everything to do with
operating within the paradigm (which the FAA happens to
like - as do the vast majority of OBAM aircraft builders).
Bob works in the certified field; this is his line of work and influences
his opinion. Not that there is anything wrong with that. However if you
think FAA certified makes something better, you might consider a 1950's
Delco or Ford Prestolite automotive generator and mechanical points voltage
regulator are FAA certified on aircraft! Is that better than a small light
Denso alternator with IR? Bob's crow bar is not certified.
B&C alternators & regulators are not certified. Does that make them bad?
NO. There is no magic to FAA certification. We have the freedom to use
Denso alternators in our kit planes, an in my opinion we should exercise
that option, not that Bob's baseline system is bad. I just don't think it
automatically should be the De facto design.
You remind me of individuals who have a lot of opinions
about a book they've never read. The crowbar OV
protection system IS certified sir, several times over. I've
stated this numerous times in this thread. All of B&C'S many
STC'd installations of both belt and pad driven alternators
use the LR/SB series regulators all of which have crowbar
ov protection.
No disrespect to Bob, and sorry if that offends anyone.
You couldn't offend me if you tried. I won't permit it.
You do amaze me with your lack of understanding
as to what the real issues . . .
Why has Bob's crow bar experienced premature trips? Stuff happens. I read
about the capacitor fix and understand why it helped. It seems to me, as an
electronics amateur, whenever you have transient conditions (dv/dt), throw
a good old capacitor in the mix. It always seems to mellow a circuit out.
(mellow - a non-technical term for filter to dampen transient voltage
spikes.) When in doubt put a capacitor in. (kidding)
This isn't about ov protection. It's about control.
Does your ND alternator of choice turn ON and OFF
at the flip of a switch? Once it's in operation,
can it be turned OFF? Do all alternators with the
ND brand on them operate in this manner? How does
one insure at the parts counter that the alternator
being considered will operate within the currently
accepted paradigm?
If not, then you're proposing a new paradigm. Which is
fine . . . but be prepared to explain it in sufficient
detail that everyone knows the physics upon which your
recommendations are based . . . and they understand and
accept the new paradigm. This has nothing to do with
opinions, only facts and customer perceptions of value
in the proposed paradigm.
There is never a 100% guarantee any device, including a simple crow bar or
a ND alternator will always work as designed. Simple things like a crow bar
& circuit breaker should work as Bob would point out. The same applies to
Denso alternators. However the idea propagated that a Denso failure means a
colossal OV condition is not valid. The usual Denso failure mode is
passive, by just dying.
That's a no-brainer sir. 99% of all failures in all
systems are passive. That's what keeps FBOs in business
fixing all those things that broke and didn't bring the
airplane down (or put the pilot into a situation he
couldn't handle). The vast majority of accidents do not
involve systems failures of any kind.
People want a 100% guarantees about everything in life and what they put on
their aircraft. Keep it simple; consider a stand alone Denso as an elegant
simple solution. Consider that crow bar could fail passively and not work
when needed without the pilot being aware of it. Bob said this is unlikely.
BINGO. I agree a simple crow bar should work, with emphasis on should. Same
with a Denso alternator, it is unlikely you will have an OV condition. At
least the ND alternator has a built in fault light (which will indicate
many faults). Nothing is perfect. Take a chance on life
A romantic philosophy sir, but even the greatest of
chance-takers took great pains to understand the territory
into which they planned to venture.
> "Jack Eckdahl" wrote:
>George: The alternator that failed was a Nippon Denso, 60 amp, internally
regulated.
Jack: I recall under peculiar conditions you observed your ND alternator
going to 16 volts. Also with the ALT switched off it produced power after
starting the engine. The technique of turning the alternator on after start
was your normal procedure. Obviously something was different than before,
since it always worked well and would not make power until switching it on.
You also noted that voltage varied 13 to 16 with load. By using a normal
procedure of manually switching the alternator ON after starting and OFF
before shut down, you forced an abrupt ON/OFF thru the regulator. This is
known to cause grief. (Read below-The IC chip inside the alternator is a
microprocessor and its internal protections only work if it is powered
during engine start and stop.)
I recall pointing out sources for brand new 60 amp ND alternators to you.
Not sure what you ended up doing but assume you are flying around FHD with
your new ND alternator. My prediction is if you stop the practice of
switching the alternator ON/OFF manually and get a NEW 60 amp ND
alternator, you will have a lifetime of trouble free alternator service
(with out crow bar). Odds are in your favor. The only other recommendation
I have is add a cooling blast tube to the rear of the alternator, and avoid
continuous operations above +30 amps. Heat is the killer of semi-conductors.
ND alternators have an IC chip that provides many safety and fault
protection functions including OV protection. In fact this microprocessor
chip may have thousands of transistors VS. a Plain-Jane external VR with 2
or 4 transistors. Therefore doing abrupt things repeatedly stresses the
chip overtime. It just was not designed to be used like that. You got away
with it for a while, but eventually is started to fail (with out dramatic
affect I might add).
This would be amusing if it weren't so serious. In one breath
you extol the virtues of a "brand new" ND alternator while
in the next, you cite the value of de-rating to 30 amps,
supplying cooling air, modifying operating techniques that
don't bother the alternator on a C-172 but might be stressful
on the brand new ND . . .
The IC chip also provides soft starts and load dump protection. SOFT START
means a large demand will not cause the alternator to instantaneously slam
full open but will ramp up to avoid a voltage overshoot. LOAD DUMP
protection, keeps voltage variation to a min with a large drop in load.
You cite facts not in evidence. The LR series regulators
were tuned to provide the slightly under-damped servo response
for step functions in both command and load. It's a classic
taks for tailoring servo response. If the internal regulator were
so whippy, LOAD DUMP ISSUES WOULD NOT EXIST. It's a regulator's
inability to control the worst case load reduction that
causes the high energy voltage transient.
When I say load dump I don't mean dropping the B-lead abruptly with an OV
relay, I mean turning the landing lights OFF. I would like to see a
two-transistor external voltage regulator do this.
Come on over to B&C . . . I'll show you one.
The typical IR is more advanced than the typical ER.
What's this mean? It's got 10-100x the transistors and they're
all on a chip instead of soldered to a board. There are features
that the older designs don't have but none of these things
point to any "better" performance with issues you've cited.
Paul's http://www.periheliondesign.com/suppressors.htm may solve the
problem of killing a healthy ND alternators when a nuisance trip of a
B-lead OV relay opening while the alternator is under load. Who knows, it
can't hurt.
It's Eric's product as I recall, not Paul's. Further, it has
nothing to do with nuisance tripping. It illustrates a means
by which an IR alternator can be CONTROLLED irrespective
of the reason for controlling it. OV protection is but one
more layer on a system that's already several layers deep.
However my electrical system design philosophy (the stew I am cooking) is
to keep it simple. I assume the chance of my alternator going into a real
out-O-control OV condition from a drive transistor short is so small I
accept. Just like I accept my single engine will continue to turn and my
single wing spar will not fail in flight. (Sometimes these also fail, but
we maintain them and fly within limits to assure they get us back on the
ground safely.)
You're entitled to accept any paradigm you wish. Just be
sure your audience understands the paradigm shift when
the proposed system does not operate like the one in
a C-172.
There has been much rhetoric about the dangers of IR alternators and the
evil of that one field drive transistor. The theory is the transistor
failure inside the IR bypasses the OV protection of the IC chip. This in
turn causes the mother of all OV conditions. Not to beat the horse to death
(which is a bloody caucus being picked at by vultures at this point), but
this scenario is a theory NOT born out by the proven reliability in
service. No car or kit plane I know of has ever had this condition from my
research. I looked high and low and found nothing, nada, zip, zero. I am
not saying it has never happened or cant happen (it can in theory), but
there is no proof or documentation it has. If we are going to get
scientifically rigorous, than we need the data, otherwise it is ignorant,
to use Bobs words.
This is not rhetoric to state that if the transistor shorts,
the alternator takes off for the moon. It is not rhetoric to
state that some IR alternators cannot be externally controlled
for normal operations, much less for recovery after a failure.
These are called deductions based on failure mode effects analysis.
Show me any cases of a ND alternator having a real honest to goodness
(documented) shorted field drive transistor resulting in an over-voltage
condition, urban legend aside. Sporadic OV module problems are much more
prolific than the non-existent alleged alternator run-a-way.
Numerous folks have experienced failures of IR alternators. Some
of them were ND alternators. Since we might expect to be in
communication with perhaps 5% of the OBAM community, it's not
a stretch to suggest that 3 hard failures I'm aware of over
the past 8 years has been repeated 20X for the community at
large.
The voltage problem (16 volts) you had was far from a wild run-a-way.
Voltage Run-a-way elicits thoughts of a train going down the mountain with
no brakes, terror, panic, destruction and emotion. That is why when you tie
the BAT master and ALT together, so the alternator is turned on
automatically (i.e., DPST switch). If you need to shut the ALT down,
manually pull the CB.
Jack's experience was not mitigated by the fact that
his alternator was "not in a wild run-away" . . . the
battery was the only thing standing between his
failed alternator and all the other electro-whizzies
in his airplane. If the battery had been used up
or even disconnected, the voltage would rise much
faster and much higher.
See:
http://aeroelectric.com/articles/Alternator_Failures.pdf
. . . also, role of the battery in an ov event starting
at "Rev B" on page 6 of:
http://www.aeroelectric.com/articles/Crowbar_OV_Protection/DC_Power_System_Dynamics_C.pdf
> "Jack Eckdahl" wrote:
>I'm not sure that my experience should cause others to avoid this unit.
In my opinion using a ND alternator as is, provides an acceptable risk
while gaining a lighter, simpler and cost effective electrical power
source. Everything in aviation has risk, and the outcome depends on how you
manage these risks. Bob says that crow bar failure is not likely. BINGO!!
I am saying run-a-way voltage in a ND alternator is not likely. Again my
opinion aside, facts like the field service history of ND alternators
indicate their IR alternator are pretty darn good. I dont think the
Japanese ND engineers that designed these devices are ignorant. (The auto
industry is very aware of OV and has lots of electronics to protect.)
Jack: If you replaced your rebuilt alternator with a new one, assuming you
have stopped flipping the alternator ON an OFF manually, you will be fine.
The BAT master should turn the ALT on simultaneously (i.e., DPST switch).
If you need to disable the alternator pull the CB.
> "Jack Eckdahl" wrote:
>I know that hundreds of airplanes are flying successfully with them.
I have no idea about aftermarket rebuilds or second tier replacement parts
VS. OEM parts from ND. ND alternators can be bought new easily at
discounted price if you shop around. The medium frame 60 amp ND's are more
readily available as a rebuild, but they can be bought new if you look.
Okay, you've fenced your paradigm in a bit tighter. You
seem to be suggesting that only a "brand new ND" alternator
is suited to operation in your proposed paradigm. Which
part number? Will it offer positive ON/OFF control via
the little wire out the back?
Compare the price of a B&C and an over the counter stock 60 amp ND
alternator. The whole B&C kit $820: alternator, regulator and brackets. If
you buy a New ND alternator ($180 retail, $120 discounted), brackets and
parts (approx $40-$60), your cost is about $250, the cost of Vans 60 amp ND
alternator kit (with a rebuilt alternator). The B&C cost 3 to 4 times more.
Is it worth the cost? It all depends on you opinion. Nothing wrong with
spending the money but dont expect 100% reliability from the B&C, even on a
dark and stormy night.
This isn't about reliability. It's about failure mode
effects. If the B&C goes south, it shuts down passively
and lights the light. Then we bring "plan B" on line
and continue the flight in comfort. This may not conform
to your idea of component reliability, but it does
conform to my idea of SYSTEM reliability.
Despite the B&C advertisements, balanced rotor and all, there is no
proof, data or facts that the B&C system will achieve superior reliability
over the stock ND alternator.
If you're looking for component reliability, you're
correct. If you're looking for system reliability,
my data is backed up by FMEA supported by 15 years
of field history and a lot of experience in conducting
such studies.
However if you are talking about reliability of a B&C or Stock ND
alternator set-up against certified 1950 and 60s technology factory
aircraft electrical systems, than yes, they are both way more reliable than
the old certified stuff.
Now in theory may be B&C is better, but it cant be proven.
So let's "assume" that it isn't?
The reason it cant be proven is the data or statistics are not available.
The reason for that is no one is tracking it. Does B&C contact all
customers with a service bulletin when a problem is found? That would be
nice. If you point to a ND alternator problem, like the one above, than you
can point to several B&C problems.
Until a couple of years ago, I was tightly coupled to
B&C's field experience with their products. I worked out of
their booth at OSH 12 straight years. I've talked to
thousands of B&C customers (both happy ones and unhappy ones)
Our warranty was "no unhappy customers" . . . EVERY customer
was encouraged to bring any problem back to B&C for resolution.
You're assertion with respect to pointing at B&C's problems
is wishful thinking on your part sir. I've been there
and it was my job to design products with a high degree
of SYSTEM reliability and to quickly resolve what few
problems did arise.
>Robert L. Nuckolls, III Wrote:
>Which only illustrates the ignorance of our customers promulgated by your
rhetoric and Van's equally ignorant advice.
Bob: I like to think they we have a different opinion not ignorant.
Quote: (snip) ignorance of our customers (snip) and Vans equally ignorant
advice.
You just called everyone ignorant Bob. With all due respect that sounds
condescending and insulting. May be you meant something else, but I take
umbrage to that. No one likes to be called ignorant.
I'm sorry, but you've just demonstrated your own shortfall
for understanding of the issues and facts upon which your
dissertation is based. Call it what you will . . .
Do you talk to Van.
I have talked to Van many times. I've asked to do a weekend seminar
for their staff like I did for Lancair. I'm going to do
one in their neighborhood and HOPE some of their staff will
attend. I may have to specifically invite them and/or offer
free tuition.
I think your crow bar is great as a simple cheap solution to protecting
alternators with external regulators, which need protection, but not on IR
alternators, which is designed to work without any other OV protection.
I'll suggest that you know nothing about design details
and philosophy of anyone's built in regulators . . . nor
are you privy to schematics upon which one bases a failure
mode effects analysis.
Van recommends NOT installing an OV module on the 60amp ND alternator,
because it can and does cause damage to them. Bob's comment and use of the
word *ignorance* in describing Van's and Paul's opinion is dogmatic.
They BLAME the ov system for killing an alternator when
if fact, root cause for the failure comes from attempts
to CONTROL the alternator. The alternator with a b-lead
contactor is vulnerable to the same kind of failure whether
or not OV protection is a part of the control system.
Again, call it what you will . . .
I don't know Van personally but I have met him and talked to him several
times over the last 15 years, building two of his kits. He is a very smart
conservative guy, and has a degree in engineering, as I do. From Van's
stand point ND alternators have been damaged with crow bar trips. Why did
Bob call the man ignorant? Whether intentional or accidental, a crow bar
trip can damage an ND alternator. This fact is bore out by the induced
failure Jack had, described above.
I've talked to Van at OSH and at several fly-ins.
You betcha. When it comes to airframes, engines and flight
controls, I am ignorant. I also don't know squat about brain
surgery or particle physics. Van's forte' is demonstrably NOT
founded in the physics and practice of fabricating electrical
systems. His "kit" drawing is 1950's C-172 in which he has
substituted a modern, IR alternator. "Ignorance" is not a
pejorative but an accurate description of demonstrable
fact.
We dont know what data Van is working on. The man after all has over 4200
planes flying of his design and been in the kit plane market for 30 years,
which gives him a little creditability. To call his opinion or Paul's
opinion ignorant is not sensible. Everyone has the best intention here, and
their suggestions are safe and reasonable in my opinion, whether you or I
agree or not.
I agree with Vans opinion that you should NOT use an OV module with an IR
alternator, but I also agree with Bob. If you feel that you cannot rely on
an IR and it's on-board OV protection than go with a crow-bar-ed external
VR alternator. An external VR adds complexity, wiring, cost and weight and
scheduled maintenance and testing, but it works.
I can accept the IR and the minimal risk alleged that there is a
statistical possibility, albeit unlikely, the field driver transistor can
short. My decision to use an IR alternator and no crow bar gives me a
light, simple, compact, cheaper system requiring no maintenance and
testing. Plus parts are available nationwide over the counter at thousands
of auto part stores and auto electric shops. Of course a NEW alternator is
better than an overhauled one, but on a trip if you did have a problem, you
could buy one across the street from the airport at Auto-parts-R-us, with a
warranty. My old home airport had a large import auto salvage yard with in
walking distance from my hanger.
Therefore Van's advice is not ignorant or Pauls flavor of opinion less
valid than Bob's, technical minutia aside. Bob can't guarantee the crow bar
will never have a false trip or fail passively. He can't do it. Go ahead
and say unlikely, but never say never. Like wise, Nippon Denso can't
guarantee a high voltage failure, but ND engineers do know about OV. They
understand OV and designed their product to minimize the chance of it
happening. From the field service history in cars and experimental planes,
ND did a great job. There are other alternator brands, some better than
others, but in my opinion the ND is probably the best.
Which part number?
The ND alternator with an IR is designed as a stand-alone unit. The
interaction of and value of an OV module (crow bar) with an IR alternator
is of dubious value. If the OV module can never false trip, than you will
never damage the alternator. However that is not how it works in the real
world. If Paul's B-lead suppressor works than that might be an option,
allowing a safer way to incorporate a crow bar type device (Bob's or
Paul's) safely on a ND alternator.
Adding a crow bar to an IR alternator is really an effort in belt and
suspenders. If you try to have your cake and eat-it to, you may end up with
the worst of both worlds. Dont mix and match systems. (Too much spice in
one stew is bad.)
Accept the fact what ever you do, when you fly a plane, especially one you
build with systems you designed, you are risking life and limb NO MATTER
WHAT YOU DO.
Except that we CAN design an electrical system that will
NEVER be a link in the chain of events contributing to
a catastrophe
A single pilot in a single engine airplane is more risky than driving a car
crazy folks behind the wheel sharing the same road. I firmly believe you
can beat the General Aviation odds, but that might mean more pilot
training, not more electrical gadgets. The pilot is the most dangerous
thing in the plane, not the voltage regulator. Build your plane to fly with
out it.
Voltage regulators are not the issue. Alternators you
cannot control are the issue.
I think it is fair to disagree, right? I say go with an IR alternator with
no extra OV protection. My best advice is design your systems as simple as
possible, while still getting the job done. Have a back-up, but be reasonable.
George, the boat sailed and you weren't on it. You have
misinterpreted my words and seem to have totally missed
the concepts of failure tolerant design. You've
demonstrated a lack of understanding of many simple
You've also misstated simple facts. You've yet to demonstrate
the need for supplying folks with the most universal
concepts in the discipline being discussed.
I don't think it's helpful to offer designs that depend
on selection of a particular brand and part number of
an alternator (which you have yet to identify).
Put any name on it you wish sir, but it doesn't change the
outcome.
I'm reminded of the words of a wise philosopher who stated
"When the best-you-know-how-to-do is compromised to
placate those who would offer anything less, only less-
than-the-best wins." Please fly your airplane in good
health but I must continue to base my recommendations on
the best I know how to do whether or not you understand
or embrace it.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Control input |
>
>I have an FFA-approved Jeppessen flight simulator and the controls are far
>too sensitive . . . the slightest input results in huge flight attitude
>changes. Jeppessen no longer sells or supports the simulator, and we've
>been unable to locate the author of the software so that we could get a
>patch written. We've tried all the "tricks" and existing inputs, and have
>managed to slow it down somewhat, but far from enough.
>
>During efforts to correct the problem, I found that the control inputs
>function through a variable rheostat; Apparently the greater the control
>input, the more current flows through the rheostat. Which leads me to
>wonder if perhaps we might be able to solve our problem by use of a
>resistor ahead of the reheostat; perhaps even a variable resistor so we
>could experiment.
>
>I'd very much appreciate your thinking.
Thank you for the kind words . . .
Is it a rheostat (2-wire) or potentiometer (3-wire)
connection? If the latter, it's easy to add resistance
to both ends of the pot to scale the output voltage.
If it's a 2-wire, then you need a smaller pot and some
added series resistance to change the scale factors.
But yes, you're perceptions of a possible solution by
adjusting the resistor networks are correct. See:
http://www.aeroelectric.com/temp/pot_scaling.gif
Bob . . .
________________________________________________________________________________
| From: | Phil Birkelbach <phil(at)petrasoft.net> |
| Subject: | Re: Aeroelectric List Format |
That's funny, I thought that Bob was giving away the updates to his
book. I guess I must have imagined that. I reckon you could write your
own book and give it away for nothing, but it doesn't seem fair to ask
someone else to give away their hard work.
Yahoogroups has most of the features that you have described. There is
nothing stopping you from starting one of those or creating your own
internet resource. I guess I don't see the point of just complaining
about this resource, if you think there is a better way then "get after it".
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB - Finishing Up
http://www.myrv7.com
Eric M. Jones wrote:
>
>When the Federal government and IBM were struggling in court a decade ago, IBM's
defense strategy was to send truckloads of documents to the government prosecutors.
When the prosecutors asked for the slightest clarification on any point,
IBM would ask for a geological amount of time to answer the question, then
responded with more truckloads of documents. IBM kept this up until the government
simply gave up and went away.
>
>This is to illustrate that all methods of argument are not equal, and some lead
nowhere. I suspect that this "public email list server" has its structural limits,
and we have exceeded them mightily.
>
>So what to do....? I suspect that the Aeroelectric Connection (or its clone) should
be turned into a free document that can be edited continuously online like
Wikipedia or other open source documents. Although one could charge for the
subscription, the consensus seems to be that free subscriptions and paid advertising
works better.
>
>Good textsbooks like the Aeroelectric Connection remain unread for the most part
since people absorb what they find of most interest at the moment. Books also
freeze a particular technical viewpoint, and the technology is changing too
fast for this to be the medium of choice.
>
>The Aeroelectric list is handicapped by many operational limitations, such as
no graphics attachments, no video clips, short display times (seven days goes
zooming by), obscure formatting restrictions, etc.
>
>The wonders of the internet allow magical connections between people. We aren't
doing it yet and as a result problems with discourse follow. The list is tiresomely
repetitive, running the same debates on and on, just because the medium
makes it so easy to forget all the arguments previously posted. I could suggest
just numbering the arguments like the old joke about the comedian convention.
Mr. X and Mr. Y lashing each other about load dump, "Well, that's old # XY-LD135Z.
I thought we resolved that....let's see....two years ago? Let's put on
our thinking caps (the beanie with the little propeller on it), and seek a better
answer.
>
>Regards,
>Eric M. Jones
>www.PerihelionDesign.com
>113 Brentwood Drive
>Southbridge MA 01550-2705
>(508) 764-2072
>
>"What the West really has to offer is honesty. Somehow, in the midst of their
>horrid history, the best among the Gaijin learned a wonderful lesson. They
>learned to distrust themselves, to doubt even what they were taught to believe
>or what their egos make them yearn to see. To know that even truth must be
>scrutinized, it was a great discovery...."
> -- David Brin, "Dr. Pak's Preschool"
>
>
>
>
________________________________________________________________________________
| From: | "DonVS" <dsvs(at)comcast.net> |
| Subject: | Ferrels for use in screw connectors |
Bob or anyone who knows,
I have a new AFS 2500 engine monitor and it has screw type connectors. I
like the unit and want to use it. Does using a ferrel on each wire make
this device less likely to have problem connections? TIA. Don VS
________________________________________________________________________________
| Subject: | Re:Real data on OVP/etc (disinterested?) |
| From: | "Matt Prather" <mprather(at)spro.net> |
Hi Bob,
...
snipped a bunch
...
I have no idea about aftermarket rebuilds or second tier replacement parts
VS. OEM parts from ND. ND alternators can be bought new easily at
discounted price if you shop around. The medium frame 60 amp ND's are more
readily available as a rebuild, but they can be bought new if you look.
Okay, you've fenced your paradigm in a bit tighter. You
seem to be suggesting that only a "brand new ND" alternator
is suited to operation in your proposed paradigm. Which
part number? Will it offer positive ON/OFF control via
the little wire out the back?
I have an idea...
Most people probably have access to a local auto parts retailer which has
an alternator test machine (with a motor and belt drive, etc). It seems
like it would be a simple task to pick an alternator off the shelf and
take it to the bench and test this aspect of performance using their
machine. It might take a bit of convincing of the salesperson to let you
come to the back room and play with their machine. It should be easy to
rig up a jumper from the control lead pigtail that could be disconnected
and then grounded once the machine is up and running.
Remember to tell the salesperson that the alternator is being installed in
an off-road vehicle.
Admittedly, that the alternator can be turned off via the control lead
doesn't obviate the need for an OVP circuit. Even so, it does make it
simple to be able to install an electrical system that a Cessna driver
could operate without fear of damage.
Regards,
Matt-
________________________________________________________________________________
| From: | Frank & Dorothy <frankvdh(at)xtra.co.nz> |
| Subject: | Re: Aeroelectric List Format |
> I suspect that the Aeroelectric Connection (or its clone) should be
turned into a free document that can be edited continuously online
I don't see that working.
1. How do you ensure quality? i.e. if its freely editable, then anyone
can add any misunderstanding or inaccuracy or urban myth to it.
2. What about liability? For me in NZ, its not a big issue. But you're
in the litigious USA. Perhaps you post something slightly inaccurate, or
maybe it is accurate but not well explained. It's used by someone
building a Lancair IV which subsequently has an electrical failure,
crashes, and kills all aboard. Will the lawyers come after you? Will you
be giving away information to help someone else if it means risking
financial ruin?
3. Some time ago, I tried to run something similar... I called it "The
Bunny's Guide to RV Building" (RV being a Vans RV-6 aircraft). As I
built my RV, I added photos and text (some my own, a fair amount
extracted from the RV-list archives), specifically aiming it at being an
improvement on Vans' manual. The model I worked with was that I
maintained the web pages, and asked people to email me with
improvements, additions, etc. I got lots of feedback saying what a great
resource it was. But I only got about half a dozen submissions in about
6 years. I'm not sure why it didn't work.
4. What we have now works. I've bought a copy of Bob's book, and I think
it is good value. Why change?
5. Advertising-supported web sites just mean that readers pay for the
content to someone else. You pay in wasted bandwidth and wasted time.
6. Books don't update themselves. A significant part of authoring is
editing.
7. To some extent, the archives at Matronics are "the book writing
itself". But without the editing!
Me, I'm of the "think about what you're planning before destroying
something" ilk.
Frank
>I didn't mean Bob should not be paid for his labors. I meant -- if Bob chose
>to give away the book and have advertising on the site it might be a plus
>for all concerned. He would probably make out better too--and the book would
>update itself.
>
>I see you are one of the "love it or leave it" ilk. Well, mine is the
>"improve it if possible" ilk
>
>Regards,
>Eric M. Jones
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Aeroelectric List Format |
Eric M. Jones wrote:
>
>When the Federal government and IBM were struggling in court a decade
ago, IBM's defense strategy was to send truckloads of documents to the
government prosecutors. When the prosecutors asked for the slightest
clarification on any point, IBM would ask for a geological amount of time
to answer the question, then responded with more truckloads of documents.
IBM kept this up until the government simply gave up and went away.
I've seen this technique used many times. I used to work in
the railroad accident investigation and analysis business.
Asking for (or delivering) more pounds of paper than could
be considered useful is common ploy used by both sides but
usually when there are truths to be keep hidden.
>
>This is to illustrate that all methods of argument are not equal, and
some lead nowhere. I suspect that this "public email list server" >has its
structural limits, and we have exceeded them mightily.
How so? Can you elaborate a bit?
>
>So what to do....? I suspect that the Aeroelectric Connection (or its
clone) should be turned into a free document that can be edited
continuously online like Wikipedia or other open source documents. Although
one could charge for the subscription, the consensus seems to be that free
subscriptions and paid advertising works better.
You're certainly free to mount that kind of effort . . .
>
>Good textsbooks like the Aeroelectric Connection remain unread for the
most part since people absorb what they find of most interest at the
moment. Books also freeze a particular technical viewpoint, and the
technology is changing too fast for this to be the medium of choice.
Depends on the text. Physics books printed in 1945 are just as
accurate for the presentation of simple ideas as a physics book
printed today. Of course, the transistor and plasma display weren't
talked about in '45 but superconductivity was. The simple
understood.
Further, I STILL prefer a printed book for random access of
tid-bits from lots of data. Catalogs are good examples where
looking at the whole printed page where you get side-by-side
comparison of similar products. It's also difficult to
match portability of the printed book. I've had a lot of
requests NOT to bind the book . . . the 3-ring format
lays nicely flat on the workbench.
I don't see the printed book going away soon.
>
>The Aeroelectric list is handicapped by many operational limitations,
such as no graphics attachments, no video clips, short display times (seven
days goes zooming by), obscure formatting restrictions, etc.
This presumes that significant numbers of participants
have a desire/need to exchange multimedia items. Matt needs
to be careful too about both data volumes and risks for
transmission of malicious files. I have a website where
I can easily publish quick illustrations. Matt has provided
a photo-upload service (that same service would handle sketches
scanned as .gif files). I suspect that few of the 1200 or
so folks who subscribe to this List would ever upload a
modern graphic so that still leaves us with a hand-full
of people who would communicate with visuals more complex
than text.
>
>The wonders of the internet allow magical connections between people. We
aren't doing it yet and as a result problems with discourse follow. The
list is tiresomely repetitive, running the same debates on and on, just
because the medium makes it so easy to forget all the arguments previously
posted.
Yup, happens in boardrooms and meetings all over the
world every day. At the core of any successful venture
there are a cadre of holders-of-tribal-knowledge who
provide instant random access to historical perspectives.
We used to have a lot of them a RAC but every time one
of them retires, a series of meetings somewhere in the
plant become a little less guided by simple-ideas from
the past.
Further, the List is like a classroom . . . a new set of
participants every "semester". One might rightly
be disappointed if discussions ARE NOT repeated. A discussion
never repeated is a discussion that has become either
irrelevant -OR- has ceased to grow the collective knowledge
of those who watch/participate.
How many times does the average physics professor get to
present an introduction to superconductivity over his/her
teaching career? Now, as engineers, we should expect to
become bored and impatient when it's been too long since
we discussed the next greatest thing. But as a teacher, I
see more value in the AeroElectric List as a classroom for
simple-ideas than as a showroom for the latest inventions.
I could suggest just numbering the arguments like the old joke about the
comedian convention. Mr. X and Mr. Y lashing each other about load dump,
"Well, that's old # XY-LD135Z. I thought we resolved that....let's
see....two years ago? Let's put on our thinking caps (the beanie with the
little propeller on it), and seek a better answer.
I've told folks for years that the 'Connection is as
much their creation as it is mine. The past few months
discussions will be strong drivers in updates of the
regulator, ov and alternator chapters. In fact, I might
just update those three chapters.
I'd be interested in your thoughts. I've been pondering
ways to turn this activity into a retirement business
and bail out of the certified rat-race. Thoughts have
included a series of how-to-videos, seminars-on-a-DVD,
a hands-on super-seminar where the attendees "wire up"
a whole system, etc.
By the way, Dee and I are going to be in Plymouth weekend
of 13/14. I'll invite you to sit in on all or
any part of the seminar . . . we'll be staying over Sunday
night because of ticketing hassles so perhaps we could
do some useful plotting for the future.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Ferrels for use in screw connectors |
>
>Bob or anyone who knows,
>I have a new AFS 2500 engine monitor and it has screw type connectors. I
>like the unit and want to use it. Does using a ferrel on each wire make
>this device less likely to have problem connections? TIA. Don VS
Depends on what the "ferrel" does. If it adds insulation
support, it might be a useful thing to do. I doubt that quality
of the connection goes up where the screw mashes down on
something hoping to maintain electrical integrity. I had
one reader suggest that you crimp the smaller diameter molex
pins (.062") onto each wire and then put the pin into the
screw-clamp. This would certainly help provide mechanical
support for vibration resistance . . . but probably won't
help with electrical integrity.
Bob . . .
________________________________________________________________________________
| From: | Mickey Coggins <mick-matronics(at)rv8.ch> |
| Subject: | Re: Aeroelectric List Format |
> There might be room for both concepts to coexist.
I agree. I enjoy the interactive conversations coming
into my mailbox, and I like how easy it is to search
the Matronics lists. What would be great is a FAQ
that could be both a starting point for new members
of the list, and a place to point someone when they
ask a question that has been hashed to death.
In fact, I'm pretty sure we have already discussed
this issue, and someone wrote a kind of FAQ, but
I can't even recall where it is.
--
Mickey Coggins
http://www.rv8.ch/
#82007 finishing
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Power/ground terminal blocks |
>
>Thanks for the input Bob. The fuseblock suggested by Kevin is exactly
>what I'm
>looking for. My system will be most similar to "Z-29". Just a very basic
>battery-only system. My plane has no starter or alternator, although I
>may add
>a wind generator at some point in the future. I will only be powering my GPS,
>Intercom, and COMM radio from a battery, via something like the
>fuseblock Kevin
>suggested. I will also provide a spare 12v jack, as well as a ground charging
>jack.
>
>Thanks for the input,
You're welcome. Sounds like you got a good handle on it!
I'd never considered the fact that Z-29 might be the whole
enchilada. Good luck with your project.
Bob . . .
________________________________________________________________________________
| From: | "DonVS" <dsvs(at)comcast.net> |
| Subject: | Ferrels for use in screw connectors |
Bob,
I goofed on the spelling of ferrules. Please see
www.alliedelec.com/catalog/pf.asp?FN=101.pdf. The AFS2599 uses a screw
connector where the screw moves a jaw like device together. I thing that
the ferrules and this type of closure device should be adequate. Any
thoughts? Thanks. Don
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Robert
L. Nuckolls, III
Subject: Re: AeroElectric-List: Ferrels for use in screw connectors
>
>Bob or anyone who knows,
>I have a new AFS 2500 engine monitor and it has screw type connectors. I
>like the unit and want to use it. Does using a ferrel on each wire make
>this device less likely to have problem connections? TIA. Don VS
Depends on what the "ferrel" does. If it adds insulation
support, it might be a useful thing to do. I doubt that quality
of the connection goes up where the screw mashes down on
something hoping to maintain electrical integrity. I had
one reader suggest that you crimp the smaller diameter molex
pins (.062") onto each wire and then put the pin into the
screw-clamp. This would certainly help provide mechanical
support for vibration resistance . . . but probably won't
help with electrical integrity.
Bob . . .
________________________________________________________________________________
| Subject: | Re: Aeroelectric List Format |
| From: | "Matt Prather" <mprather(at)spro.net> |
The problem with an FAQ is that it requires a fair amount of maintenance,
and then people often still won't dig into it before posting a question.
Bob's book is actually the FAQ, if you ask me. And he maintains it, and
doesn't charge very much for it.
A rather sadistic idea: Make the interface to the list an 'ask jeeves'
system. Only allow people to post questions after they have gone through
the motions of searching the archive. Just kidding (mostly).. :)
Bob's analogy that this list is like a classroom is one which gives me
mental peace. I rather like that way of thinking about it.
Regards,
Matt-
>
>
>> There might be room for both concepts to coexist.
>
> I agree. I enjoy the interactive conversations coming
> into my mailbox, and I like how easy it is to search
> the Matronics lists. What would be great is a FAQ
> that could be both a starting point for new members
> of the list, and a place to point someone when they
> ask a question that has been hashed to death.
>
> In fact, I'm pretty sure we have already discussed
> this issue, and someone wrote a kind of FAQ, but
> I can't even recall where it is.
>
> --
> Mickey Coggins
> http://www.rv8.ch/
> #82007 finishing
>
>
________________________________________________________________________________
| From: | "Bill Denton" <bdenton(at)bdenton.com> |
| Subject: | Toggle Switch & Breaker |
A couple of questions:
What configuration of toggle switch (SPST, SPDT, etc) would I need to do the
following:
Down position - Off - Input not connected to any output
Center position - Low - Input connected to one output
Up position - High - Input connected to second output
This would be used to feed a strobe power supply that offers both a low and
a high output. A source of supply for this switch would also be appreciated.
Second question:
The Rotax 503 wiring diagram calls for a 15-amp fuse between the
rectifier-regulator and the positive battery terminal. Would there be any
reason not to use a combination toggle switch/circuit breaker, such as the
W31X2M1G-15 from Wicks Aircraft Supply for this purpose?
Thank you!
________________________________________________________________________________
| From: | <gmcjetpilot(at)yahoo.com> |
| Subject: | Re: New/rebuilt Alternators IGN wire (Was: real data |
on ovp/etc)
Matt wrote:
>Okay, you've fenced your paradigm in a bit tighter. You
>seem to be suggesting that only a "brand new ND" alternator
>is suited to operation in your proposed paradigm. Which
>part number? Will it offer positive ON/OFF control via
>the little wire out the back?
I think your paradigm is way too complicated for me, but I will try to explain.
Matt I am not suggesting anything, but from common sense to me NEW with all OEM
Nippondenso parts is better than rebuilt/used.
(STORY)
My personal experience with alternator problems, rebuilt alternators and over the
counter trade-ins was on my Acura Legend. After approx 12 years and 200,000
miles the alternator stopped working altogether. I brought it to a local auto
electric shop that had been in business for 60 years. You could tell because
the walls and floor was littered with the remains of 100's and 100's of alternators
and associated parts. Well I wanted my actual original alternator and not
an exchange so decided to let them rebuild it. New brushes and something else
was what it needed? I don't recall. It did not work when I replaced it so returned
it. The second try worked a bit better but never as good as it had. The
battery did not seem to get as much charge. Well it died again while on a road
trip about a year later. I went to a local Pep Boys, near where my car died
and exchanged it for a rebuild. I replaced it in the parking lot myself with minimum
tools. I was impressed with the quality of the
finish
on the rebuild. It even came with documentation showing a Power Vs. RPM graph
from a test run for that rebuilt unit. It has worked well for many years since
and still is going. This car is now my dedicated airport car since I fly all
the time and leave it parked for days and weeks at a time. (Side note if I am
gone more than a week I disconnect the battery, because the computer will drain
the battery in about 2 weeks and always has.) SO WHAT DOES THAN MEAN, nothing
but may be not all rebuilds are the same. For my plane I still will buy new
and for my car I guess I'll go to Pep Boys. However sometimes you can get a new
one for less than a rebuild.
>Matt wrote:
>Will it offer positive ON/OFF control via the little wire out the back?
Little black wire? I think on my wire harness it is yellow or green, but you are
talking about the IGN wire that goes to the IR-internal (voltage) regulator.
Positive ON/OFF Control? You don't need any POSITIVE control. When ever the engine
is running the alternator should be ON, always. When ever you turn the master
BAT switch OFF the alternator should be turned off (at the same time), while
not under load (turning). You must never turn the BAT off with the ALT on.
The IR is automatic and there is no need to manually control the alternator. If
there is a fault it should shut down automatically.
The IGN wire is not qusi ON/OFF switch. It is not the intent use. It does work
as an ON switch in that if you start the engine with the ALT OFF (no power to
the IGN wire) it should not make juice. However turning the alternator ON (power
to the IGN wire) after starting the engine with it off, it will TURN ON. It
will also FRY IT. Don't do it. May be you should read my SNIP.
Now can you turn it off with the engine still running? I do not think so. My current
plane and new 45amp ND are not running yet. I sold my last plane and can't
go out and test it to tell you. However I would not even want to do it because
there is no reason and I don't want to damage my alternator.
Why do you want to manually shut the alternator off? Why? That is a bad idea. I
never, never would turn the ALT or BAT off with the engine running (well except
for one special condition). Why would you ever do this? What purpose would
this serve? When would you shut a perfect alternator down with the engine running?
The IR has it's own auto fault protections and will shut down. There is
that rare OV case I mentioned in the previous post (SNIP) that in theory a scenario
happens where nothing will turn the alternator OFF. As I said I never found
any documented run-a-way cases with an IR Denso alternators. So what happens
if this does occur?
Most if not all the reported OV cases are old memories of old time alternators
with their old time external regulators. However if you did have a runaway OV
condition with your ND alternator, pulling the power to the IGN wire of the IR
alternator may do nothing. First the IR should have caught it. If id did not
than it may have failed. In the above scenario the regulator is by-passed. The
only cure is pulling the B-lead circuit breaker (CB). You say you are using a
fuse for the B-lead and not a panel mounted CB. Ok, than turn the BAT master
off (the one special condition I mentioned). You are saying if you turn the BAT
off than the engine will stop (EFI, dual EI, electric pumps). Well the engine
will keep turning if you have a carb, mechanical FI, mags or self-powered ignition.
If your engine is electrically depended, it should be on a standby battery
to drive it's essential buss, separate from the main BAT bus. If you can't
stand the loss of your main BAT buss, use the big u
gly
(alleged noisy- but not necessarily so) B-lead CB in the panel that almost every
certified factory plane has. You act as a manual crow bar by pulling it. Again
very unlikely and never proved to me to be a real concern. However if it did
happen, you have an out. By the way if you did turn the BAT off, once the alternator
burns out, and it would, you have the option to turn the BAT master
back on. Land.
Here is the deal, I am a KISS guy, not the Band KISS but KEEP IT SIMPLE. I would
wire a Denso just like the manufactures who use them in their products (cars,
trucks, tractors, folk lifts, outboard motor's, etc...). The IGN wire should
be energized before cranking the engine and remain energized until you shut the
engine down and than turn the BATT switch off. There is no separate switch
provided to the alternator. Also according to the Niagara Air parts Kit you should
(MUST) tie the ALT to the BAT. (do it like this)
http://www.niagaraairparts.com/alt-instr.pdf
Let the automatic functions of the alternator's internal regulator IC chip take
care of starting and shutting down the alternator. There is no need to manually
control it. All we have to do to start and stop the alternator is turn the
pulley (start and stop the engine).
I think you said so a Cessna driver can't damage it. Good idea. I don't care for
the Cessna split rocker switch (tied together so you could not turn the BATT
off without turning the ALT off also.)
(STORY)
Way back when I was an instructor about a few students (none of mine thank God)
who would accidentally turn the BAT on and split the switch, leaving the ALT
off, which you can do. They would start the engine, taxi out and fly away with
the ALT off. They did not notice the amp meter discharge or little yellow light.
After flying say less than an hour they would have a complete loss of electrical
power (drained battery). Well they would find the problem and would turn
the ALT on, which was off the whole time. Guess what. The alternator started
pumping so much current to charge the dead battery, with all the radios and lights
still on, the big CB (b-lead from alternator) would POP. They forgot to
load shed before powering the alternator back on. Not wanting to reset the breaker
more than once, they would than make an unscheduled stop and a call to the
flight club. That is why I like a single toggle switch (DPST) for the BAT/ALT
and not the Cessna split rocker style switch.
-Ladies and Gentleman in the Event of an Emergency
The alternator IGN goes thru a CB, so if you need to shut it down manually than
pull the CB. If that does not work pull the B-lead CB in the panel (read above).
A scenario that would call for this is if the alternator stopped working in
flight. To save drain from the regulator, if any, pull the CB, since the alternator
is not working anyway. There are procedures on the B757 that call for
pulling a CB per "non-normal checklist" (emergency checklist is not used by Boeing),
so it is perfectly normal to use a CB as an occasional switch.
There are up to 4 AC GENS on a B757: 2 engine, 1 APU and on planes 1 Hydraulic
driven GEN. All are the same 90 kVA GEN. They connect and parallel automatically
and shut down if there is a fault automatically, with no pilot action. What
is the point? They don't even trust airline pilots to throw the right switch
so the automated it. Well not really but to the point let your little DENSO alternator's
automatic IR functions work as designed; It is smarter than you when
it comes to knowing when to turn itself ON and OFF. My theory is to see how
few switches you can use, not how many. RV-8 should not have more switches than
a B-757. Less is more, KISS
Why do we have to make this so hard? Is there a need to throw a dozen switched
to accomplish an engine start in a single engine airplane?
>Matt wrote:
>It seems like it would be a simple task to pick an alternator off the shelf and
>take it to the bench and test this aspect of performance using their machine.
Not sure what you paradigm you are driving at? I hope that answers your question.
By all means buy a used alternator if you like. I was happy with Pep Boys for
my Acura.
You mention checking the rebuild in the store. That will not mean much if it craps
out on your inaugural flight to Oshkosh in your new Sky Scooter 2005. However
if you can, in my personal opinion (and I mean opinion), buy a new one. I
have no facts to back that up. It is just my feeling NEW is better than rebuilt
for an alternator. Paul asked a few questions and was told that rebuild is really
RRR - Repair & Replace as (little as) required. So some parts, regulator,
bearings for example might have 200,000 miles on it? I don't know if that is
true. Again it must depend on who does the rebuild. Also there are aftermarket
DENSO repair parts. I don't know if the quality is as good as OEM but I guess
there is a chance other brand replacement parts are not as good? The nice part
of Pep Boy's or AutoZone is I think you can buy a lifetime warranty. If you
get on the web you might find a DENSO distributor that will sell you at least
a factory re-manufactured alternator will all DENSO
parts?
Copy gratuitously what has worked before. This is not a test, so its not cheating.
Good luck. George
Subject: Re:Real data on OVP/etc (disinterested?)
From: "Matt Prather" <mprather(at)spro.net>
Hi Bob,
...
snipped a bunch
...
I have no idea about aftermarket rebuilds or second tier replacement parts
VS. OEM parts from ND. ND alternators can be bought new easily at
discounted price if you shop around. The medium frame 60 amp ND's are more
readily available as a rebuild, but they can be bought new if you look.
Okay, you've fenced your paradigm in a bit tighter. You
seem to be suggesting that only a "brand new ND" alternator
is suited to operation in your proposed paradigm. Which
part number? Will it offer positive ON/OFF control via
the little wire out the back?
I have an idea...
Most people probably have access to a local auto parts retailer which has
an alternator test machine (with a motor and belt drive, etc). It seems
like it would be a simple task to pick an alternator off the shelf and
take it to the bench and test this aspect of performance using their
machine. It might take a bit of convincing of the salesperson to let you
come to the back room and play with their machine. It should be easy to
rig up a jumper from the control lead pigtail that could be disconnected
and then grounded once the machine is up and running.
Remember to tell the salesperson that the alternator is being installed in
an off-road vehicle. Admittedly, that the alternator can be turned off via the
control lead
doesn't obviate the need for an OVP circuit. Even so, it does make it
simple to be able to install an electrical system that a Cessna driver
could operate without fear of damage.
Regards,
Matt-
________________________________________________________________________________
| From: | Kevin Horton <khorton01(at)rogers.com> |
| Subject: | Re: New/rebuilt Alternators IGN wire (Was: real |
data on ovp/etc)
On 6 Aug 2005, at 23:33,
wrote:
>
> Matt wrote:
>
>> Okay, you've fenced your paradigm in a bit tighter. You
>> seem to be suggesting that only a "brand new ND" alternator
>> is suited to operation in your proposed paradigm. Which
>> part number? Will it offer positive ON/OFF control via
>> the little wire out the back?
>
> Little black wire? I think on my wire harness it is yellow or
> green, but you are talking about the IGN wire that goes to the IR-
> internal (voltage) regulator.
>
> Positive ON/OFF Control? You don't need any POSITIVE control. When
> ever the engine is running the alternator should be ON, always.
> When ever you turn the master BAT switch OFF the alternator should
> be turned off (at the same time), while not under load (turning).
> You must never turn the BAT off with the ALT on. The IR is
> automatic and there is no need to manually control the alternator.
> If there is a fault it should shut down automatically.
>
> The IGN wire is not qusi ON/OFF switch. It is not the intent use.
> It does work as an ON switch in that if you start the engine with
> the ALT OFF (no power to the IGN wire) it should not make juice.
> However turning the alternator ON (power to the IGN wire) after
> starting the engine with it off, it will TURN ON. It will also FRY
> IT. Don't do it. May be you should read my SNIP.
>
> Now can you turn it off with the engine still running? I do not
> think so. My current plane and new 45amp ND are not running yet. I
> sold my last plane and can't go out and test it to tell you.
> However I would not even want to do it because there is no reason
> and I don't want to damage my alternator.
>
> Why do you want to manually shut the alternator off? Why? That is a
> bad idea. I never, never would turn the ALT or BAT off with the
> engine running (well except for one special condition). Why would
> you ever do this? What purpose would this serve? When would you
> shut a perfect alternator down with the engine running? The IR has
> it's own auto fault protections and will shut down. There is that
> rare OV case I mentioned in the previous post (SNIP) that in theory
> a scenario happens where nothing will turn the alternator OFF. As I
> said I never found any documented run-a-way cases with an IR Denso
> alternators. So what happens if this does occur?
>
How will you remove all electrical power from the aircraft in the
event you ever have a smoke in the cockpit event? In theory, the
fuses and CBs are supposed to prevent that sort of thing, but these
events still happen due to various wiring faults (e.g. an insulation
failure could cause a small ground wire to short to a large power
wire - the ground wire would smoke before the circuit protection on
the power wire would open).
The only way to remove all electrical power in most archetures is to
shut down the alternator and open the battery contactor. Even if you
aren't worried about an OV event, you should consider the smoke in
the cockpit case, as it could kill you, even if you are flying VFR.
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Toggle Switch & Breaker |
>
>A couple of questions:
>
>What configuration of toggle switch (SPST, SPDT, etc) would I need to do the
>following:
>
> Down position - Off - Input not connected to any output
>
> Center position - Low - Input connected to one output
>
> Up position - High - Input connected to second output
This is accomplished with a two pole, three position, progressive
transfer switch like B&C's S700-2-10
Use of this swich is illustrated in a number of the Z-figures
in the book and in chapter 11 of the 'Connection.
>This would be used to feed a strobe power supply that offers both a low and
>a high output. A source of supply for this switch would also be appreciated.
>
>Second question:
>
>The Rotax 503 wiring diagram calls for a 15-amp fuse between the
>rectifier-regulator and the positive battery terminal. Would there be any
>reason not to use a combination toggle switch/circuit breaker, such as the
>W31X2M1G-15 from Wicks Aircraft Supply for this purpose?
How is the alternator tuned On/Off otherwise? If wired
per instructions, is there no way to turn it off?
One can always substitute breakers/fuses/switch-breakers
for each other.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | New/rebuilt Alternators IGN wire |
>
>
>Matt wrote:
>
>
> >Okay, you've fenced your paradigm in a bit tighter. You
> >seem to be suggesting that only a "brand new ND" alternator
> >is suited to operation in your proposed paradigm. Which
> >part number? Will it offer positive ON/OFF control via
> >the little wire out the back?
>
>
>Positive ON/OFF Control? You don't need any POSITIVE control. When ever
>the engine is running the alternator should be ON, always. When ever you
>turn the master BAT switch OFF the alternator should be turned off (at the
>same time), while not under load (turning). You must never turn the BAT
>off with the ALT on. The IR is automatic and there is no need to manually
>control the alternator. If there is a fault it should shut down automatically.
Very good sir. We've finally arrived at the mutual
level of understanding needed to resolve the new
paradigm.
Since day-one for the installation of power sources
in aircraft, the pilot has been offered positive control
of all sources in the form of panel mounted switches.
These were additions to other forms of positive control
like magneto switches (if you can start and stop the
engine by means of fuel controls, why do we need magneto
switches?), fuel shutoff valves, etc.
Many of these features became part of CAA and eventually
FAA requirements for certification. One might argue
that since much of what the FAA requires adds no value
to the safety of aircraft operation we can target
ANY and ALL requirements as superfluous or unnecessary
under any new paradigm we choose to embrace.
The simple-idea supporting your paradigm is that
you don't find it necessary to have positive control
over an alternator.
Now, if you wish to gain support of this paradigm, you
need to do a Case-A, Case-B comparison of the ideas
that support the Positive Control paradigm and demonstrate
how they (1) were unnecessary or in error, or (2) have become
obsolete with new technology or operating philosophies.
It is inadequate to state that this new paradigm's philosophy
is based only upon inarguable features of the latest-and-
greatest technology. You must also supply the logic needed
to encourage abandonment of the old paradigm. For example,
at one time, wax and whale oil were the illumination fluids
of choice and then kerosene came along only to be replaced by
evaporated "white gas" (naptha) blown through mantles, etc.
In each step, there were no compelling desirable features
being abandoned from the old paradigm and new paradigms
did not present unsurmountable or unacceptable features
(nobody was ever electrocuted by a Coleman lantern and
nobody ever set their house on fire by smoking while
screwing in a new lightbulb).
If you have such an case to make, I'm eager to hear
it.
Bob . . .
________________________________________________________________________________
| Subject: | Re: New/rebuilt Alternators IGN wire (Was: real |
data on ovp/etc)
| From: | "George Braly" <gwbraly(at)gami.com> |
>Will it offer positive ON/OFF control via the little wire out the
back?<
>>Positive ON/OFF Control? You don't need any POSITIVE control. When
ever the engine is running the alternator should be ON, always. When
ever you turn the master BAT switch OFF the alternator should be turned
off (at the same time), while not under load (turning). You must never
turn the BAT off with the ALT on. The IR is automatic and there is no
need to manually control the alternator. If there is a fault it should
shut down automatically.<<
Oh... my goodness. Where to start?
I just finished doing a formal Functional Hazard Assessment for an
alternator system.
That, aside:
Something mundane. How about troubleshooting electrical problems in the
hangar?
Do you REALLY want the alternator field drawing 3 amps while you have
the battery ON ?
In the air, what if you get a "flying" short of the spinning alternator
windings that is intermittent while operating and causing lots of
voltage and current spikes/faults to drop into the electrical system - -
and you can't kill the alternator without killing the entire electrical
system and creating an emergency?
What if a diode fails and the level of electrical noise into the system
makes radio communication very difficult?
Regards, George
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> (Was: real data on ovp/etc) |
| Subject: | Re: New/rebuilt Alternators IGN wire |
(Was: real data on ovp/etc)
>
>
> >Will it offer positive ON/OFF control via the little wire out the
>back?<
>
>
> >>Positive ON/OFF Control? You don't need any POSITIVE control. When
>ever the engine is running the alternator should be ON, always. When
>ever you turn the master BAT switch OFF the alternator should be turned
>off (at the same time), while not under load (turning). You must never
>turn the BAT off with the ALT on. The IR is automatic and there is no
>need to manually control the alternator. If there is a fault it should
>shut down automatically.<<
>
>
>Oh... my goodness. Where to start?
>
>I just finished doing a formal Functional Hazard Assessment for an
>alternator system.
>
>That, aside:
>
>Something mundane. How about troubleshooting electrical problems in the
>hangar?
>
>Do you REALLY want the alternator field drawing 3 amps while you have
>the battery ON ?
This may not happen as long as you don't move the alternator
control switch to ON after closing the battery contactor.
>In the air, what if you get a "flying" short of the spinning alternator
>windings that is intermittent while operating and causing lots of
>voltage and current spikes/faults to drop into the electrical system - -
>and you can't kill the alternator without killing the entire electrical
>system and creating an emergency?
>
>What if a diode fails and the level of electrical noise into the system
>makes radio communication very difficult?
Good points for the positive control paradigm. Does anyone
have additional offerings for (or against) either paradigm?
Bob . . .
________________________________________________________________________________
| Subject: | Re: New/rebuilt Alternators IGN wire (Was: real |
data on ovp/etc)
| From: | "George Braly" <gwbraly(at)gami.com> |
>Do you REALLY want the alternator field drawing 3 amps while you have
>the battery ON ?
This may not happen as long as you don't move the alternator
control switch to ON after closing the battery contactor.
*******************************
Bob,
I thought the "no control" paradigm assumed that when the BAT switch is
ON, that the alternator is powered - - with no way to interrupt the
alternator. Right?
In that case, the bus voltage will be <12.5 and the alternator field
should be 100% energized, since the VR sense voltage set point will
normally be > 13.8 Volts.
Am I missing something ?
Regards, George
________________________________________________________________________________
| From: | "DonVS" <dsvs(at)comcast.net> |
| Subject: | Ferrels for use in screw connectors EDITED |
Bob,
I goofed on the spelling of ferrules. Please see
www.alliedelec.com/catalog/pf.asp?FN=101.pdf. The AFS2500 uses a screw
connector where the screw moves a jaw like device together. The contact
area is about half that of a faston blade. I think that the ferrules and
this type of closure device should be adequate, but would like your thoughts
on this. Thanks. Don
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Robert
L. Nuckolls, III
Subject: Re: AeroElectric-List: Ferrels for use in screw connectors
>
>Bob or anyone who knows,
>I have a new AFS 2500 engine monitor and it has screw type connectors. I
>like the unit and want to use it. Does using a ferrel on each wire make
>this device less likely to have problem connections? TIA. Don VS
Depends on what the "ferrel" does. If it adds insulation
support, it might be a useful thing to do. I doubt that quality
of the connection goes up where the screw mashes down on
something hoping to maintain electrical integrity. I had
one reader suggest that you crimp the smaller diameter molex
pins (.062") onto each wire and then put the pin into the
screw-clamp. This would certainly help provide mechanical
support for vibration resistance . . . but probably won't
help with electrical integrity.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> (Was: real data on ovp/etc) |
| Subject: | Re: New/rebuilt Alternators IGN wire |
(Was: real data on ovp/etc)
>
> >Do you REALLY want the alternator field drawing 3 amps while you have
> >the battery ON ?
>
> This may not happen as long as you don't move the alternator
> control switch to ON after closing the battery contactor.
>
>
>*******************************
>
>Bob,
>
>I thought the "no control" paradigm assumed that when the BAT switch is
>ON, that the alternator is powered - - with no way to interrupt the
>alternator. Right?
>
>In that case, the bus voltage will be <12.5 and the alternator field
>should be 100% energized, since the VR sense voltage set point will
>normally be > 13.8 Volts.
>Am I missing something ?
Oh, I guess I don't know how Van suggests that it be wired, nor
do I know how George was suggesting it be wired either. I HAVE
seen a number of articles and drawings where the IGN wire was
routed through a conventional alternator control branch of a
split rocker . . . which would be emulated nicely by use of the
2-10 progressive transfer. This would allow the pilot to get the
engine running before adding alternator loads. However, if
wired as I suggested in earlier drawings where a 2-3 was
used for DC PWR MASTER, then of course, the IGN terminal would
"get hot" with the bus.
Then, there's yet another configuration of modern alternators
that offer the so-called, "one-wire" solution. These guys
are popular with the marine and hot-rod crowd. Of course the
b-lead is always hot in these vehicles.
Having said that, some of the chips have an AC sense lead
that gets a signal from the stator leads. Depending on the
chip designer's philosophy, this signal could be used to disable
the field when the alternator was not turning.
An example of this philosophy can be viewed at:
http://www.irf.com/product-info/datasheets/data/irvr101.pdf
This puppy even offers a 9600 baud serial port for
data transfer between chip and a monitor/control
system.
No doubt about it folks . . . there's a whole lot of
whippy things goin' on out there. There may be a great
temptation to embrace these new things. But we should
take care lest we find ourselves in a new, unanticipated
mode of operation by way of an unhappy surprise.
Bob . . .
>Regards, George
>
>
>--
>
>
>-- incoming mail is certified Virus Free.
Bob . . .
--------------------------------------------------------
< Throughout history, poverty is the normal condition >
< of man. Advances which permit this norm to be >
< exceeded -- here and there, now and then -- are the >
< work of an extremely small minority, frequently >
< despised, often condemned, and almost always opposed >
< by all right-thinking people. Whenever this tiny >
< minority is kept from creating, or (as sometimes >
< happens) is driven out of a society, the people >
< then slip back into abject poverty. >
< >
< This is known as "bad luck". >
< -Lazarus Long- >
<------------------------------------------------------>
http://www.aeroelectric.com
________________________________________________________________________________
| From: | <gmcjetpilot(at)yahoo.com> |
| Subject: | Re:Real data on OVP/etc (disinterested?) Bob |
From: "Robert L. Nuckolls, III" nuckollsr(at)cox.net
Subject: Re:Real data on OVP/etc (disinterested?)
> It depends on your paradigm . . .
That was my whole point. Bob you are focused on one small aspect. Aviation safety
is a much broader subject than voltage regulators.
>Which is not an opinion sir. Nor is it a preference for anyone's
>stew. For the past 70+ years, folks flying airplanes have had
>switches on the panel that offer (1) absolute control over all sources
>of power in the aircraft and (2) has a remote probability of a failure
>that propagates across multiple systems. The FAA requires that I
>work within that paradigm when offering up new systems for certification.
You missed the point. Opinion does guide your perspective. I dont worry what the
FAA says. You are also uninformed about alternator control; I do have complete
control of my IR regulator. If all hell breaks loose, I can pull that big-old
B-lead 50 amp panel mounted CB out. (In a real emergency the BAT master off
. My engine and flight instruments are not electrically dependent or are automatically
backed up with internal batteries, Dynon, Garmin.) The only way to
get true fail-safe or fail-passive system is at least two or three fully ISOLATION
and independent electrical sources working side by side.
>I'm completely mystified by this statement. How does the fact that
>the FAA will or will not bless any particular reasoning make it
>an automatic no-brainer for someone building his own airplane?
>This isn't about regulations or opinions, it's about design goals
>that satisfy the paradigm under which the owner/operator of the
>end product. 99+ percent of OBAM airplane builders are comfortable
>with and most understand the paradigm that controls how certified
>airplanes operate.
Bob dont be mystified. That is so condescending. What I wrote was so bewildering,
you became disorient and confused. Wow I did not know my words had the power
to mystify. No one is proposing a panacea here Bob and were ae a lot smarter
than you give us credit for.
>Do you have data about how the various IR alternators operate such
>that you can DEMONSTRATE that anything with ND's name on it will
>operate in the paradigm that applies to the vast majority of airplanes
>flying? If not, then your recommendation is not backed up by
>demonstrable and consistent performance characteristics and is,
>in fact, purely a preference for a different taste in your
>bowl of stew.
Do I have data? Bob, that is an inane thing to ask. There are 148 models of ND
alternators with internal regulators and internal fans ranging from 30 to 130
amps. There are 66 models of ND alternators with external regulators and internal
fans from 90 to 136 amps. Plus there are another 15 various models with
external fan models. There are a few million ND alternators in daily use, 24 hours
a day, every day of the year working with excellent performance and reliability.
If this does not prove, demonstrable and consistent performance characteristics,
to BAD. All your posturing is absurd. You seem to lack common sense
and reasonable rational. These are experimental planes. If you have never been
in one, there is a warning placard that informs passengers that an experimental
airplane does not meet standard aircraft certification standards. Bob, I never
said my recommendation was a substitute, replacement or better than your
brilliant concepts, architecture and philosophies.
>No argument there. None-the-less, folks continue to
>come forward with their failure experiences. Not a "current
>generation ND alternator? Don't know. Not a stock
>regulator? Don't know. Would a well considered ov
>protection system of ANY flavor have saved the day?
>Probably . . . likelihood of dual failures in same
>system on same flight are extremely rare. At least
>one customer with the b-lead contactor and OVM-14
>crowbar module has written to me expressing relief
>that the system was in place when his IR alternator
>went tits up.
Bob, I am glad people write you to relive themselves. I think part of that relief
is from all the misinformation and rumors about IR alternators you spread.
With all the sensationalized talk it is easy to see how someone could have an
unreasonable heightened sense of concern. What folks continue to come forward?
You are the master of inflammatory insinuation. How many accidents have been
caused by an OV and did they involve a ND alternator? ZERO. You have a better
chance of your 0-2 gage-battery cable grounding, burning thru the engine mount
or just falling off. Electrical system failure is a very small % of the total
GA accidents. Statistically, regardless of where you put the regulator or if
you use a crow bar or not, your accident statistics will not change.
>But do you agree that the risk is not zero? In fact,
>one of our brothers here on the list reported such an
>incident recently. If I were trying to convince someone
>of anything, I could have wished that Jack's failure would
>have occurred two hours out, at night, over mountains
>and took out a bunch of radios to boot. When one is looking
>for propaganda fodder, the sweat-drenched, nail-biting
>stories are much more useful. Gee Jack, you let us down.
Bob that is just more emotional sensationalized comment is not worthy of an engineer,
that you claim you are. You are clueless, I mean ignorant to the meaning
of incident. This is what a pilot would do Bob: Over the mountains you loose
your alternator; Turn off all your non-essential electrical stuff and continue
to fly. You pull the ALT circuit breaker and the B-lead breaker. When you get
near your alternate (nearest suitable airport) you turn the electrical stuff
back on and land. Modern avionics like GPS pull a few 1/10th of an amp, so you
could run on BAT power for a while. Nighttime you should have a flashlight.
If you have a glass cockpit you should have enough battery power for at least
30-45min VFR and an hour plus for IFR. If you also have electronic ignition and
fuel injection, all electronic you would need a bigger back-up battery. Dual
alternators?
My viewpoint is use a Lycoming with a mechanical fuel pump, at least one magneto
or P-mag. A carburetor or mechanical FI does not need electrical power either.
The Dynon, GRT-EIS-4000, Garmin and other misc items are pulling about 5
amps total. The Dynon and GPS have self-contained batteries as well. My engine
is electrically independent as I feel it should be. I understand fault tolerance
Sir.
>Please consume it in good health.
Thank you. Pass the crackers
>You absolutely missed the point. Again, this has nothing
>to do with how much this system would please or displease
>me, the FAA or anyone else. It has everything to do with
>operating within the paradigm (which the FAA happens to
>like - as do the vast majority of OBAM aircraft builders).
Bob, no you missed the point again. /Operating within the paradigm/ is gibberish
that has no practical meaning to anyone. Common sense is the paradigm Bob. If
you cant dazzle-em with facts, baffle-em with the word paradigm.
It is not an affront to you or any device you have worked on. I have studied your
every word and understand it. I just dont want a device that SHORTS to ground
to work, no matter how clever or certified it is. I dont really care what the
FAA thinks as long as I get my paper work signed. It is my butt and for a VFR
plane, with no main buss electrical dependency to stay in the air, I am safe.
What else can I say? What dont you understand? I designed my system to eliminate
the need for a crow bar and external regulator. From personal experience
with a ND alternator in my cars and plane, I expect over 4000 hours of operation
before failure (200,000miles & 12 car years). So when my alternator reaches
2000 hours or 8 years I will remove and replace it.
>You remind me of individuals who have a lot of opinions
>about a book they've never read. The crowbar OV
>protection system IS certified sir, several times over. I've
>stated this numerous times in this thread. All of B&C'S many
>STC'd installations of both belt and pad driven alternators
>use the LR/SB series regulators all of which have crowbar
>ov protection.
I must remind you of yourself, since you talk about stuff you are clue less all
the time. When the guy with the Subaru had the electrical failure you pontificated
and criticize with little knowledge of facts. When you stated how B&C starters
are better than Sky Tec with bushings and blaa blaa, The Sky Tec guy put
you in your place. You should have apologized but you replied with something
stupid comment about lets do some test. Again you did not have the facts. I am
not perfect but you are ignorant.
You also remind me of someone who loves to argue. I see B&C has a standby alternator
system for the Bonanza and C210. Good for B&C. So I was not up to date.
Sue me. Apologies. Do they have any STCs to replace the main alternator on any
plane? If no, than why?
>You couldn't offend me if you tried. I won't permit it.
>You do amaze me with your lack of understanding
>as to what the real issues . . .
There you go again. What does that mean, I WILL NOT ALLOW IT. Whatever Bob. I was
making a sincere jester of concern and you throw it back at me as if I was
inconsequential and beneath you. I understand I am not worthy and of no importance.
>This isn't about ov protection. It's about control.
>Does your ND alternator of choice turn ON and OFF
>at the flip of a switch? Once it's in operation,
>can it be turned OFF? Do all alternators with the
>ND brand on them operate in this manner? How does
>one insure at the parts counter that the alternator
>being considered will operate within the currently
>accepted paradigm?
Engineers? Bob you cant control everything, you only think you can. I cant think
of a reason why I would turn off a perfectly good alternator with the engine
running. If it did crap out I would pull the B-lead CB in my panel. That would
essentially isolate it from the electrical system. (Yes I want control of my
B-lead and opt NOT to use a FUSE under the cowl where I cant access it, as you
suggest.) If I did not have the CB for the B-lead I could shut the BATT master
off. The engine would continue to run. The Dynon and GPS would be powered by
internal batteries.
>If not, then you're proposing a new paradigm. Which is
>fine . . . but be prepared to explain it in sufficient
>detail that everyone knows the physics upon which your
>recommendations are based . . . and they understand and
>accept the new paradigm. This has nothing to do with
>opinions, only facts and customer perceptions of value
>in the proposed paradigm.
I dont have customers. I am an individual and have stated so. As I clearly stated
your paradigm (oh I hate that word) is valid and needed based on your position
as guru. I dont have to prove anything. I have been honest in saying that
ND alternators have gained over a thousand of hours on single airframes. Personally
800 hours of ND time in a plane and a total of approx 6000 hours in three
automobiles (with ND alternators). As for the auto applications, the highway
safety foundation has never had a problem with ND alternators, which is not
true of many other alternators. Since records are not kept for experimental fleet,
I am going by my experience and those of other RVs (some with 2000 hours)
over 15 years. Not real scientific but it works.
>That's a no-brainer sir. 99% of all failures in all
>systems are passive. That's what keeps FBOs in business
>fixing all those things that broke and didn't bring the
>airplane down (or put the pilot into a situation he
>couldn't handle). The vast majority of accidents do not
>involve systems failures of any kind.
Cant argue with you because you are a Master Debater.
>A romantic philosophy sir, but even the greatest of
>chance-takers took great pains to understand the territory
>into which they planned to venture.
Chance-Taker? Bob you have such a PIN HOLE view of the world , aviation and aviation
safety, or at least you sound like it. I am bewildered and confounded by
your very ignorant words. I am dizzy with disbelief. You dont know me and I am
a very conservative ATP. This is just another feeble insult and a smoke screen
for the lack of an intelligent comment with substance. I dont know what is
romantic Sir, but I read what builders want to do. It is clear they are trying
to make it perfect of totally fail-safe. Which is impossible with any of your
suggestions or paradigm. If you like I will explain how an air transport category
planes electrical system works to illustrate how unsophisticated our little
DC electrical systems are.
>This would be amusing if it weren't so serious. In one breath
>you extol the virtues of a "brand new" ND alternator while
>in the next, you cite the value of de-rating to 30 amps,
>supplying cooling air, modifying operating techniques that
>don't bother the alternator on a C-172 but might be stressful
>on the brand new ND . . .
Well Bob, for someone who claims to know how an alternator works, you appear to
have a lack of any comprehension. I am not extolling any more than you are singing
about the 7 th wonder of the world called a Crow bar. WHAT DO YOU MEAN?
Look here, fact, semi-conductors life and reliability is a function of temperature.
YOUR B&Cs alternator has a diode pack (semi-conductors) on board just like
the ND, regardless of VR location. I guess B&C uses the exact same stock diodes
all ND alternators have. Keeping them cool is key to any alternator life.
I am using COMMON SENSE here, which you seem to be lacking from your fixation
of the crow bar or center of the galaxy. If you want to assure super reliability
de-rate your continuous % load. What % 50, 75? It is only a guide line Bob,
don't be a pisser. Some cars have shrouds and duct air to the back of the
alternator. Why? Cooling. Real engineers understand this and would not make such
an inane comment. Size your alternator accordingl
y. ND
makes 80 or 90 amp alternators I think are the physical size as the 60 amp. Just
common sense not quantum physics. If you can fit it there are 117-136 amp ND
alternators designed for an external voltage regulator out the Box!
>You cite facts not in evidence. The LR series regulators
>were tuned to provide the slightly under-damped servo response
>for step functions in both command and load. It's a classic
>taks for tailoring servo response. If the internal regulator were
>so whippy, LOAD DUMP ISSUES WOULD NOT EXIST. It's a regulator's
>inability to control the worst case load reduction that
>causes the high energy voltage transient.
You cite facts not in evidence? Bob, what the heck do you mean? Whimpy? What kind
of engineering term is that? That is how they work by design.
AGAIN FOR THE 10th TIME CUTTING THE B-LEAD OF AN IR ALTERNATOR IS NOT GOOD FOR
THE ALTERNATOR. IF YOU WANT A CROW BAR USE AN ALTERNATOR WITH AN EXTERNAL REGULATOR,
OR TAKE YOUR CHANCES WITH FAULTS CROW BAR TRIPS. GO AHEAD, USE A IR ALTERNATOR,
IT IS OK WITH ME.
EVERY ONE KNOWS RUNNING AN ALTERNATOR NOT CONNECTED TO A BATTERY IS BAD BAD BAD.
WHY IS THIS HARD TO GRASP BOB?
You claim to understand failure analysis. I doubt it. If you were driving your
car and the b-lead shorts (before the fuse), would you want the alternator to
burn-out (fuse) or keep working and act like a welder and set the car on fire?
(I have no idea what you will say, really, you would argue with a rock.).
We know the OV trip caused the demise because after this event the alternator did
not work anymore. ND engineers no doubt assumed this would be a rare event
(because they dont recommend OV cutouts by default. There are no OV relays in
non-aircraft applications). The IR has many functions and one of them looks at
the B-lead. While under load it will assume a short or other fault, which it
does monitor (because ND said so). Also the IC chip is connected to the B-lead
and it just might be too much for it. SO WHAT. This is condition is avoidable.
ND accepted this failure mode because it is not suppose to happen and is safer
than making a welder out of it.
>Come on over to B&C . . . I'll show you one.
OK, Ill take a rain check I would love to see that
>What's this mean? It's got 10-100x the transistors and they're
>all on a chip instead of soldered to a board. There are features
>that the older designs don't have but none of these things
>point to any "better" performance with issues you've cited.
Bob I think you have IC envy. Yes Bob more transistor means more features and performance.
You heard of computers? Well they have millions of transistors on
a small chip. More transistors the faster it works. If you built a computer like
you build your B&C VR, it would be the size of a house. I would think you could
grasp that. The IC chips inside most modern alternators does have logic circuits
(digital processes) and self-fault monitoring. DENSO will not send me
the schematics to their proprietary IC design. What I do know about special IC
chips is they are made by a handful of manufactures. They all seem to have similar
features. Here is a typical IC spec data sheet:
http://www.freescale.com/files/analog/doc/data_sheet/MC33099.pdf
>It's Eric's product as I recall, not Paul's. Further, it has
>nothing to do with nuisance tripping. It illustrates a means
>by which an IR alternator can be CONTROLLED irrespective
>of the reason for controlling it. OV protection is but one
>more layer on a system that's already several layers deep.
My mistake, yes it is another layer. I have read spec sheets on devices. If you
must use a crow bar on an IR regulator it might be a good add on (another add
on). It might help the OV relay from arcing as I think you and Paul have argued
about.
>You're entitled to accept any paradigm you wish. Just be
>sure your audience understands the paradigm shift when
>the proposed system does not operate like the one in
>a C-172.
Thank you for telling me I am entitled to an opinion. I dont need your permission
to have an opinion but thanks. Let me make it simple for you, the engine should
never stop turning in flight. Most GA planes have engines with no reliance
on external electrical power, or should. That is a good thing and should be
emulated at all cost. I understand Auto engines need power for the ignition/fuel
injection and pumps. That is one reason why I would not use an auto engine.
However an IR alternator could still be used, but you should have an isolated
power source. You never considered a DC-DC converter (battery charger) to charge
isolated battery. This is used on transport category planes.
>This is not rhetoric to state that if the transistor shorts,
>the alternator takes off for the moon. It is not rhetoric to
>state that some IR alternators cannot be externally controlled
>for normal operations, much less for recovery after a failure.
>for normal operations, much less for recovery after a failure.
>These are called deductions based on failure mode effects analysis.
Like you asked me several times above, do you have data? Look up the word rhetoric.
You should know what it means since you used it: rhetoric: The art or study
of using language effectively and persuasively.
By throwing in the word Deduction and Failure Mode Effects Analysis in one sentence,
I know you are shooting smoke. WHAT ANALYSIS DID YOU DO? FMEA is a term
that describes the tools people use doing risk based assessments and root-cause-analysis.
It is used in all kind of industries and processes. I see no analysis
but just a lot of words Bob. Now I did not say I did formal FMEA, but I did
go thru all the scenarios and made a DEDUCTION. I am not impressed when you
throw a few words around. Where is this analysis? If you dont have it you are
just spouting RHETORIC. My Risk-matrix result, for an IR alternator, in a little
single engine plane, no engine or flight critical system dependence on electrical
power, concludes the RISK is acceptable. With a B-lead CB in the pane
I can control the alternator.
>Numerous folks have experienced failures of IR alternators. Some
>of them were ND alternators. Since we might expect to be in
>communication with perhaps 5% of the OBAM community, it's not
>a stretch to suggest that 3 hard failures I'm aware of over
>the past 8 years has been repeated 20X for the community at
>large.
Numerous? OK Bob what ever you say, Failures. Hard failures? You dont even know
what the word incident means. Like you asked me several times above, DO you have
data? Prove it to me. You are throwing out numbers: 20 times, 3 to the power
of perhaps? You are real loose with the numbers. What does that mean? What
hard failure? What happened? I mean really Bob, you are hypocritical when you
ask for data and expect to give none in return Sir. Other wise it is hearsay,
innuendo and rumor. A few of these I tracked down where totally irrelevant
and where factory planes with external regulators. Forget the Failure analysis
Bull, how about some simple details. Basically WHAT HAPPENED? My I suggest if
you had a smoking gun to support your view you would say so.
>Jack's experience was not mitigated by the fact that
>his alternator was "not in a wild run-away" . . . the
>battery was the only thing standing between his
>failed alternator and all the other electro-whizzies
>in his airplane. If the battery had been used up
>or even disconnected, the voltage would rise much
>faster and much higher.
Oh, Bob you dont know that. It was mitigated by the fact the voltage regulator
was still functioning; it was no big deal. Voltage was between 13-16 volts. I
am sure in a few years this case will grow into a fairy-tale where the pilot was
electrocuted and the plane bust into flames from exploding avionics. It is
all sensation but no facts. Take a deep breath. No harm no foul. Yes the battery
helps any alternator. That is why my you dont disconnect it from the battery
normally. If you do the alternator might be damaged.
>Okay, you've fenced your paradigm in a bit tighter. You
>seem to be suggesting that only a "brand new ND" alternator
>is suited to operation in your proposed paradigm. Which
>part number? Will it offer positive ON/OFF control via
>the little wire out the back?
I address this in my post: Re: New/rebuilt Alternators IGN wire (Was: real data
on ovp/etc)
>This isn't about reliability. It's about failure mode
>effects. If the B&C goes south, it shuts down passively
>and lights the light. Then we bring "plan B" on line
>and continue the flight in comfort. This may not conform
>to your idea of component reliability, but it does
>conform to my idea of SYSTEM reliability.
If it never breaks you dont have to worry about failure mode. Plan B applies just
as much to a ND alternator as it does to anything you suggest.
>If you're looking for component reliability, you're
>correct. If you're looking for system reliability,
>my data is backed up by FMEA supported by 15 years
>of field history and a lot of experience in conducting
>such studies.
There you go. You have 15 years of crow bar data in experimental aircraft? Wow.
Well the basic ND design has been around for well over 15 years. I believe you,
but how did you get the data. You claim you conducted 15 years of field history
study. How many are in service? What about the failures happening, which
you have no idea of? One weak link in the home built world is there is no requirement
to collect maintenance data. You will see maintenance bulletins the FAAs
prints pertaining to all planes and sometimes a Kit plane will be in it, but
most non A&P builders of experimental aircraft dont report or read this publication.
There should be a FAR that requires or makes it easy for builders/repairman
to report maintenance issues, including electrical. That way we would
know whose alternator is failing.
>So let's "assume" that it isn't?
Now Bob dont be that way, you have muddled the point. You have a vested input to
the B&C design. You are proud and should be. I can see plainly that discreet
components and a crow bar is going to have a known failure mode. It does not
mean it will not fail more, but you understand how it fails. I can say my ND alternator
will be very reliable, but if it does fail, it might fail in unknown
modes. I know it is reliable and will not kill me, from my FMEA analysis I did
on a cocktail napkin.
>Until a couple of years ago, I was tightly coupled to
>B&C's field experience with their products. I worked out of
>their booth at OSH 12 straight years. I've talked to
>thousands of B&C customers (both happy ones and unhappy ones)
>Our warranty was "no unhappy customers" . . . EVERY customer
>was encouraged to bring any problem back to B&C for resolution.
>You're assertion with respect to pointing at B&C's problems
>is wishful thinking on your part sir. I've been there
>and it was my job to design products with a high degree
>of SYSTEM reliability and to quickly resolve what few
>problems did arise.
I think you are super defensive and sensitive, Sir. I wish to point at nothing.
I dont even know about all the past problems. I am not trying to discredit anything
or anyone. I think B&C is over priced not defective. However I think many
comments regarding the danger of using an IR alternator ignores the high degree
of reliability. The ND is an unknown since we cant look into the IC chip.
However that is moot since you EXPERTS have isolate the weak link, the field
driver transistor, not the IC chip. As I said the ND engineers are NOT ignorant
and these products are very mature. Regardless, you can always pull the B-lead
CB manually (if you have one and you should.
If you want to protect an individual piece of avionics, you can use a device like
a TransZorb(tm) or Mosorb that will break down at a set voltage like a zener
diode. This will blow the fuse or CB for that item (like a crow bar). This may
not be necessary since most modern electronics which have internal OV protection
and can take 30 volts and 60 volts spike (except icom a-200). Also no one
can put an exact max voltage on an OV condition. The last one was 16 volts.
Yawn, no worries.
> I have talked to Van many times. I've asked to do a weekend seminar
>for their staff like I did for Lancair. I'm going to do
>one in their neighborhood and HOPE some of their staff will
>attend. I may have to specifically invite them and/or offer
>free tuition.
That is real nice of you. Why call the man ignorant? Did he NOT get all excited
about FUSES, central ground and crow bars? Really there is nothing really new
under the sun Bob. Van has common sense and an eye on the BIG PICTURE, not just
the minutia of one possible electrical problem that is not that common any
more. (In the old days there where lots of OV because the external VRs where crap.)
>I'll suggest that you know nothing about design details
>and philosophy of anyone's built in regulators . . . nor
>are you privy to schematics upon which one bases a failure
>mode effects analysis.
Oh Geeee Bob, I suggest you have not processed the info. I told you at least 4
times I cannot get any detailed info on the IR chip inside a ND. I got some general
sales claims about OV and Load Dump protection but nothing real technical.
Again Load dump means 5-10 amps, not 30-60amps during a B-lead abortion from
a crow bar. I have studied spec sheet for other brands of IC chip sets use
for alternators. Also I have talked to NDs tech support in the US and looked maintenance
manual schematics (void of details inside the IC). They dont EVER recommend
cutting the alternator loose from the battery. Other than that both my
cars and my plane have ND alternators with internal regulators.
>They BLAME the ov system for killing an alternator when
>if fact, root cause for the failure comes from attempts
>to CONTROL the alternator. The alternator with a b-lead
>contactor is vulnerable to the same kind of failure whether
>or not OV protection is a part of the control system.
>Again, call it what you will . . .
I dont think it is a big deal Bob, dont be so sensitive. The crow bar got a little
reputation for toasting ND alternators. No one is blaming your little baby,
but there seems to be a cause and affect (Root Cause Failure Analysis per basics
of FMEA you claim to understand). It seems there is a correlation. Look IR
alternators are designed and installed in their auto application with out a
crow bar. If you must use an IR alternator make sure the crow bar is of best design
and adjusted so a false trip is unlikely. If it does POP and kill something
than that is the cost of doing business with extra protection. I will not
tell you about one dark and stormy night over the mountains when the crow bar
blew, since that is moot and dumb emotionalism.
>I've talked to Van at OSH and at several fly-ins.
>You betcha. When it comes to airframes, engines and flight
>controls, I am ignorant. I also don't know squat about brain
>surgery or particle physics. Van's forte' is demonstrably NOT
>founded in the physics and practice of fabricating electrical
>systems. His "kit" drawing is 1950's C-172 in which he has
>substituted a modern, IR alternator. "Ignorance" is not a
>pejorative but an accurate description of demonstrable
>fact.
OK Bob how much as electrons changed since 1950? My guess 1950 and 2005 electrons
are the same. I cant believe there is anything real bad about a 1950 Cessna
with the added IR alternator. We are talking about DC circuits. Bob here is your
distinguish wiring (MO) Modus Operandi:
-Central Ground (excellent idea I might add)
-B-lead fuse forward of firewall , connect to battery before buss**
-Automotive fuse block and ATQ blade fuses
-Spade connectors vs. ring
-Crow bar
**( Use of B-lead fuse vs. a panel CB sacrifices alternator control. Suggest the
overstressed claim of noise be ignored and use a panel CB, especially if you
use an IR alternator. I find it ironic Bobs technology is right out of an import
car. Japanese car imports pioneered this approach to DC power distribution.
The plastic fuse blocks are right out of a car. Bob likes, auto technology and
wiring, but does not like the IR alternator for lack of control. Well if you
use a CB for the B-lead in the panel, you have control.)
Circa 1950s Cessna (and Beech / Raytheon ) probably has crazy wily-nily grounding
schemes using multi point airframe grounds too much. It also probably has a
big fat CB on the panel for the B-lead, which is no big deal. As far as materials
I dont think Van uses 1950 wires and connectors. I am sure his kit uses
new mil spec wires and modern crimped connection. HOW BAD COULD IT BE? I looked
at Tony Bingelis Books and than yours, Bob. Wires are wires. DC circuits are
DC circuits. We are talking about a simple DC power distribution system. You
dont know Van. It is not ignorance; he just does not give a rats ass about the
smallest of electrical details that will affect .0001% of his builders. If it
gets the job done, than it is good enough.
>Which part number?
It is not my job to recommend alternators bob, but hear are some I hear has worked
for RV builders: The usual suspect are Nippondenso 100211-400; (1988-85) Chevrolet
Sprint 1.0L Nippondenso 100211-415; (1988-87) Chevrolet Sprint 1.0L
(1995-86) Suzuki Samurai 1.3L (1989) Suzuki Sidekick 1.3L Nippondenso 100211-141,
100211-155, 100211-407; (1991-85) Toyota 4Runner, Pickup 2.4L (1985) Toyota
Celica 2.4L Nippondenso 100211-203, -316, -355
>Except that we CAN design an electrical system that will
>NEVER be a link in the chain of events contributing to
>a catastrophe
Can never say NEVER in an airplane Bob. That is the answer I expect from an electrical
engineer. You can try and believe you have designed the perfect system,
but there is nothing perfect. A little piece of foam destroyed the space shuttle.
Apollo 13 went boom from a faulty heater.
>Voltage regulators are not the issue. Alternators you
>cannot control are the issue.
Oh Bob Bob Bob, you love to sensationalize, you CAN control an IR alternator: First)
Pull the B-lead CB or Second) Turn the master switch OFF. You have isolated
the alternator. I understand what you are saying, but statistically you are
myopic. The pilot is the key to safety not the engineer. Even a crap electrical
system is the most reliable thing on a small plane. Loss of an alternator
should not be fatal. What is a pilot doing flying IMC of mountains at night. You
are a typical design engineer that feels you can control everything. I understand
your engineer mentality. I dont care about a crow bar; I care about living.
Dont over estimate the significance of this one item to miss the big picture.
By adding this protection device you introduced another failure point. Does
it justify adding it?
>George, the boat sailed and you weren't on it. You have
>misinterpreted my words and seem to have totally missed
>the concepts of failure tolerant design. You
>demonstrated a lack of understanding of many simple
>You've also misstated simple facts. You've yet to demonstrate
>the need for supplying folks with the most universal
>concepts in the discipline being discussed.
>I don't think it's helpful to offer designs that depend
>on selection of a particular brand and part number of
>an alternator (which you have yet to identify).
Bob their you go again with the Bob-bastics and bombastic comments
YOU HAVE FAILED TOO....
YOU HAVE MISSED THE POINT
BOAT SAILED YOU WEREN'TT ON IT
YOU LACK UNDERSTANDING OF SIMPLE IDEAS, SIR.
YOUR CUSTOMERS, YOU AND VAN ARE IGNORANT
On size does not fit all. I work with fail-safe Cat III landing procedures, system
fault isolation manuals on transport category Jets. I am responsible for 180
min ET OP operations (long over water flights) and fully understand systems
and their relation to flight safety. You think if someone does not agree they
can't understand the brilliance of your crow bar or grasp the idea of redundancy
or passive failure Geeeeeee. I do understand.
Dont scare people with sensationalized rhetoric. That is a cheap game plan for
someone who likes to be thought of as a benevolent impartial teacher and engineer.
No rocket science, just basic DC circuits 101. How can you not understand
that? It is not as complicated as you like people to believe. EVERY ONE KNOWS
BOB CAN'T RECOMMEND THE ND ALTERNATOR. OK. YOU WIN, I AM WRONG.
>Put any name on it you wish sir, but it doesn't change the
>out come.
Yea I have a name for it.
>I'm reminded of the words of a wise philosopher who stated
>"When the best-you-know-how-to-do is compromised to
>Placate those who would offer anything less, only less-
>than-the-best wins." Please fly your airplane in good
>health but I must continue to base my recommendations on
>the best I know how to do whether or not you understand
>or embrace it.
>There Bob . . .
Well, I am reminded of two words right now myself.
I am not trying to compromise your best, be placated by you or offer anyone less
of anything. What does that mean anyway? It is silly. I am not offering anything.
I never wanted you or need you to change your recommendations Bob.
Take Care Bob
________________________________________________________________________________
| Subject: | Re: AeroElectric-List Digest: 6 Msgs - 08/06/05 |
| From: | ldodgesr(at)mmm.com |
14, 2004) at 08/08/2005 08:06:45 AM
Personally, I like the format. It opens quickly with minimal internet
facilities and you can get to the pictures and free downloads from Bob if
you want them. What a great deal!!!!!!!!!!
Larry H. Dodge
________________________________________________________________________________
| Subject: | Re:Real data on OVP/etc (disinterested?) |
| From: | "Hinde, Frank George (Corvallis)" <frank.hinde(at)hp.com> |
Just make sue the alternator has all the appropriate connections BEFORE
starting the engine, and don't disconnect anything until after the
engine has stopped.
The way this is normally done in a car if the B lead is permanently
connected to the battery and the field is switched on/off thru the
ignition switch. That's why you get the red charge light come on when
you first turn the ignition.
This may be achieved the same way in the airplane (using Bob's Z
figures) by connecting all the alternator connections to the engine side
of the Master contactor, except in the case you have a means of
disconnecting the whole alternator if the thing catches fire by turning
off the master.
By default batteries are always "ON" the alt gets connected thru the
Master contactor and normally is not turned off until after the engine
has stopped turning.
Frank
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Mickey Coggins
Subject: Re: AeroElectric-List: Re:Real data on OVP/etc (disinterested?)
-->
> By using a normal procedure of manually switching the alternator ON
> after starting and OFF before shut down, you forced an abrupt ON/OFF
> thru the regulator. This is known to cause grief. (Read below-The IC
> chip inside the alternator is a microprocessor and its internal
> protections only work if it is powered during engine start and stop.)
> ... ND alternators have an IC chip that provides many safety and fault
> protection functions including OV protection. In fact this
> microprocessor chip may have thousands of transistors VS. a
> Plain-Jane external VR with 2 or 4 transistors. Therefore doing abrupt
> things repeatedly stresses the chip overtime. It just was not designed
> to be used like that. You got away with it for a while, but eventually
> is started to fail (with out dramatic affect I might add).
>
I had not heard of this before. Are you saying that I should make sure
the alternator is on whenever the batteries are on?
--
Mickey Coggins
http://www.rv8.ch/
#82007 finishing
________________________________________________________________________________
| From: | <gmcjetpilot(at)yahoo.com> |
| Subject: | Re: New/rebuilt Alternators IGN wire |
Kevin:
Good Point in the event of an electrical fire you need to turn off the system,
excellent point. My comment that you would not want to turn a good alternator
off in-flight should be modified to include, except in the case of a fire. However
I think you need to remove BAT power as well. In some kit aircraft (and GA
aircraft in general) the reliance on electrical power makes turning the master
BAT off impossible because the engine will quit or the cockpit instruments
will blank. Serious considerations must be made when planning for an electrically
dependent engine and/or instruments. The only way is a separate electrical
system (at least a battery) that drives the min critical items. How you parallel
them (diode) is addressed in Bob's book.
Electrical fire is one of the more serious checklist on a jet liner and the SwissAir
tragedy illustrates how serious it can be. There are many many buss on a
Jet. The checklist calls for you to manually turn off all less critical buss-es
off (utility bus), after you put on O2 mask and goggles. That still does not
mean the electrical fire will be extinguished, since items are still powered,
especially in the cockpit. Than if needed you are told to FIND the source and
pull individual breakers. Lets just say you pray you never have this situation.
I don't know how many breakers I would get pulled, since I would be on the
ground ASAP. In theory you could turn everything off (AC GENS) and fly on BAT
power only, which means one stand-by AI (w/ loc/gs needles), AS and ALT, Radio/Nav,
cockpit dome light and electric controls. All glass would be dead (unless
you buy an option with extra batteries to keep the captains glass lit).
Thanks George
From: Kevin Horton <khorton01(at)rogers.com>
Subject: Re: AeroElectric-List: Re: New/rebuilt Alternators IGN wire
(Was: real
data on ovp/etc)
The only way to remove all electrical power in most archetures is to
shut down the alternator and open the battery contactor. Even if you
aren't worried about an OV event, you should consider the smoke in
the cockpit case, as it could kill you, even if you are flying VFR.
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
---------------------------------
________________________________________________________________________________
| From: | Bill Czygan <bczygan(at)yahoo.com> |
I am interested in creating an electrical system for a Rotax 503 points ignition
single carb engine. What changes from the system described on this list, would
be required. The aircraft will be an open type aircraft so weatherproofing
is important as well.
Bill Czygan
________________________________________________________________________________
| From: | "John Swartout" <jgswartout(at)earthlink.net> |
| Subject: | Headset/Microphone jack bushings |
Dear List:
It seems that the jacks supplied with my intercom came without the
flanged insulating bushings needed to ensure isolation from the metal
airframe. Can someone suggest a source?
John
________________________________________________________________________________
| From: | "Wayne Sweet" <w_sweet(at)Comcast.net> |
| Subject: | Re: Headset/Microphone jack bushings |
I found a source and had to order 100. Send a prepaid envelope and I will
slip as many as you need and return to you.
Wayne Sweet
1520 Salinas Highway
Monterey, Ca 93940
Oh, put a note to remind me what you need. I am a bit forgetful.
----- Original Message -----
From: "John Swartout" <jgswartout(at)earthlink.net>
Subject: AeroElectric-List: Headset/Microphone jack bushings
>
>
> Dear List:
>
>
> It seems that the jacks supplied with my intercom came without the
> flanged insulating bushings needed to ensure isolation from the metal
> airframe. Can someone suggest a source?
>
>
> John
>
>
>
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
Hi Dean
Were the OV events that you mentioned with an internal regulator
alternator? If so that might answer your question.
As far as I'm concerned, I've seen nothing but anecdotal evidence of the
risk from using an IR alternator. It may be extremely low and entirely
acceptable but so far all I've seen is anecdotal "proof" of that. I've
long ago learned that even though no one is yelling about their ND
(nippondenso) overvoltage failures - it tells me little about how often
such an event occurrs. There are a lot of folks making their living out
of replacing ND alternators so we do know they fail in one manner or
another. I don't recall any data being presented for inside the warranty
period let alone outside the warranty period. Unfortunately I've seen a
lot of grief in aviation caused by embracing new technology because it
was available rather than because there was any need for it or
demonstrated safety improvements from it. I no longer assume that
something newer is better. I do agree that a modern IR alternator seems
to be more reliable than a lot of the old external regulators.
Personally I'd be comfortable with an IR alternator if I had a non
electrically dependant engine AND an OVM module of some kind protecting
the supply to that $15k radio rack that you mentioned. Someone pointed
out that Jim Weir talks about that approach with guess what - a crowbar
OVM. As it happens my engine is electrically dependant and my main
alternator is an IR unit with the crowbar OVP and disconnect contactor -
but I have redundancy powered by a second electrical system and very
little avionics.
Ken
DEAN PSIROPOULOS wrote:
>
>Ok GMCJET, Eric and Paul:
>
>You all seem to eluding to something just as good or better than what Bob
>has to offer with his externally regulated alternator and OVP. GREAT, why
>don't each of you explain your COMPLETE configurations (IN PLAIN ENGLISH)
>here on this list. That way, builders who are deep into the wiring stage can
>make up their minds and maybe save a little money? I'm currently in that
>stage and have been following this thread for a LONGGGGGG TIME hoping that
>SOMEONE would produce the new cheaper, better, simpler solution for the
>externally regulated and controlled alternator with OVP. I returned the IR
>alternator that Van's supplied with my firewall forward kit because of
>threads on this list. So far I haven't really heard anything that makes me
>want to buy it back.
>
>I HAVE TO DECIDE very soon now whether to go ahead with my decision to buy a
>B&C alternator and ER with OVP like I changed my mind to do. Do I WANT to
>spend $800 dollars for these two very common items that can be had in any
>autoparts store for hundreds less?! Hell no! I'd rather spend 1/3 that much
>and use the rest for avgas on my upcoming first flight. But this little bug
>keeps nagging at me and I don't want a runaway alternator taking out the
>$15,000.00 worth of electronic equipment in my panel (even if it is DO-160
>certified). I know it happens only rarely but it DOES happen. I personally
>know of people who've had this occur in both aircraft and automobiles. All
>cases resulted in massive amounts of smoke behind the panel and expensive
>repair bills.
>
>
snip
________________________________________________________________________________
| From: | "John Swartout" <jgswartout(at)earthlink.net> |
| Subject: | Headset/Microphone jack bushings |
Ok--the envelope is in the mail. THANK YOU!
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Wayne
Sweet
Subject: Re: AeroElectric-List: Headset/Microphone jack bushings
I found a source and had to order 100. Send a prepaid envelope and I
will
slip as many as you need and return to you.
Wayne Sweet
1520 Salinas Highway
Monterey, Ca 93940
Oh, put a note to remind me what you need. I am a bit forgetful.
----- Original Message -----
From: "John Swartout" <jgswartout(at)earthlink.net>
Subject: AeroElectric-List: Headset/Microphone jack bushings
>
>
> Dear List:
>
>
> It seems that the jacks supplied with my intercom came without the
> flanged insulating bushings needed to ensure isolation from the metal
> airframe. Can someone suggest a source?
>
>
> John
>
>
>
________________________________________________________________________________
| From: | Tim Olson <Tim(at)MyRV10.com> |
| Subject: | Plane-Power Alternator at OSH |
Did anyone else see the Plane-Power booth at OSH, right next to
Sky-Tec and not too far from B&C?
http://www.plane-power.com/
I spent some time looking at their alternators, and was
impressed enough that I signed up to hold show pricing
when they're available, and so I can take time to learn
more.
They had a 70A FAA/PMA approved external regulated
model, and a 60 and 70A internally regulated model,
with OV protection (using the crowbar method). The
price was right, and at least physicially I didn't see
any issue. It was also interesting to hear that they
went for full FAA/PMA approval on their alternator
before they released any experimental alternators.
I want to learn more about their OV module, as I'd
have to assume that in order for them to put out this
product, they must have done some testing to know what
kind of failure damage is caused when the OV module trips.
I didn't get enough time to gather my thoughts and ask
every question I wanted...hoped maybe someone here could
fill in some blanks.
Also, they say that by next year, they want to have
available an aux. alternator. I'm guessing that if I'm
willing to delay that purchase, I could add it later
and the total cost of my system would be WELL under
1/2 of my original plans.
Their web page is still being built up, but here's a link
to the 60A model. http://www.plane-power.com/AL12-EI60.htm
Comments?
--
Tim Olson -- RV-10
________________________________________________________________________________
| From: | Bill Smith <ocleju(at)yahoo.com> |
| Subject: | Alternative Engines - Geo/Suzuki |
Alternative Engines - Geo/Suzuki
If you are interested in alternative engines for
experimental aircraft you are invited to
join the flyGeo_uncensored group and learn about the
fantastic Geo/Suzuki engines used in
aircraft.
http://groups.yahoo.com/group/FlyGeo_uncensored
Both bolt on gearbox and cog belt redrives and all
other aircraft
conversion parts are available for very reasonable
cost. Turbo
versions are available also. Gearbox type redrives for
around US$1750-
The Geo/Suzuki engine uses about half the fuel that
the two stroke
engines use.
The 1.3 litre four cylinder Suzuki engine beats the
Rotax 912 in
power and weight, again both gearbox and belt type
redrives are
available.
The Geo/Suzuki one litre engine weighs a little more
than a Rotax
582, it produces 62 HP normally aspirated but with a
better, flatter
torque curve.
All those advantages plus flying engines with the
hours up to prove
them and last but not lease, far, far cheaper than a
Rotax two or four stroke engine.
One person on the group has over 1000 hours on one
installation.
FlyGeo_uncensored is a very active and helpful group
that is also a fun group and is not
doubt one of the fastest growing aircraft alternative
engine groups.
http://groups.yahoo.com/group/FlyGeo_uncensored
The FlyGeo_uncensored Management
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Alternator system design goals . . . |
I thought it would be useful to recap the thought processes behind
the writings I've done concerning installation of alternators (and
generators) on airplanes. In particular, I'll share thinking on the
internally regulated alternator and try to show how we got to where
we are today:
Old History:
From day-one, all power sources in aircraft have been controllable
by the pilot from the cockpit. Without going into all the reasons
old, new, come and gone, I think it's sufficient for this discussion
to suggest that it's an operating mode we're all familiar with.
We expect to see it in a certified ship. We were taught how to
use these features both in normal and abnormal operating conditions.
Recent History:
For the first 8 or so revisions of the 'Connection,
the writings in chapters on alternators, ov protection, and
regulators cited what we knew and were currently using in
certified aviation, and by default, a majority of OBAM aviation as well.
A few folks at the leading edge of the OBAM aviation effort were
installing automotive take-offs which offered the siren call of
inexpensive, simple, light, readily available, etc, etc. However,
in order to utilize these products, it was the builder's responsibility
to assess suitability to task which includes questions like:
(1) Does this work exactly like the system I am replacing?
(2) What features of the current paradigm must I have to give up
and are these trade offs acceptable? If acceptable to me, how
about the guy who's going to buy my airplane someday?
(3) Are there features unique to this system that require
changes to system integration, operating procedures, and
maintenance? Are these acceptable both to me and any
future owners of this aircraft?
(4) Are there any new cost of ownership considerations?
(5) Does the new system have any new or shared risks with the old
system?
This list may not be all inclusive but it's the lion's share of
considerations in play when I crafted the first version of Figure
Z-24 in the 'Connection.
The goal was to offer the builder a drop-in, plug-n-play substitution
of an old design philosophy with a new one. The reasoning was that Figure
Z-24 would directly substitute an IR alternators for the alternator/
regulator/ovp suite of components in any of the preceding architectures.
For folks who wanted, could afford and appreciated the value of working with
suppliers of the old technology, then configure as shown in the base
drawing. If you wanted to substitute the more modern approach without
giving up ANY of the features shown in the un-modified Z-figure, then
Z-24 suggested a means for doing that.
The Cabbage Patch:
Now comes the mud puddles that were impossible
to avoid stepping in. While virtually all combinations of ov
protection, alternator regulators, and externally regulated alternators
could be mixed/matched pretty much at will we find that not all
internally regulated alternators were the same. New issues of pedigree for
regulators were suggested. Some builders demonstrated a
vulnerability these alternators had for being victim to their
own load-dump responses just because they were turned off under
load. Some alternators could be controlled ON/OFF by means of the
control wire, others were Once ON, Always ON.
Some folks jumped on the "evil ov protection scheme" band wagon
and elected to ignore the fact that risks were the same whether the
alternator was shut off (1) manually, (2) in response to a
real ov event, or (3) in response to a nuisance trip of the
ov protection system IRRESPECTIVE OF THE STYLE of that
protection. Others suggested a degree of incompetence for
anyone who even suggested that their favorite IR alternator
was capable of presenting an OV event while ignoring
my special obligation as author of The Book to publish the most
universal solutions that met MY design goals for no change
of paradigm.
In the barroom brawl that ensued, folks came forward with all
manner of rational for approaching the problem "differently"
re-enforced with plenty of tomatoes and cabbages lobbed into
the discussions that ran far afield - basically ignoring the
goals cited above which MINIMIZED the shift from historical
features which allowed us to:
(1) Have absolute control of all power sources in the airplane
(2) Be able to switch sources on/off at will at any time
without regard to component safety.
(3) When there were issues of switching sequence, pilots
were relieved of responsibility for proper sequence
by inclusion of the progressive transfer DC master
(2-10) or classic split-rocker master switches.
As I view the task before us now, may I suggest it can be
very simply expressed as follows:
(1) Are we truly interested in crafting an IR alternator
installation that fits the time honored paradigm for
absolute control with minimized risk for inadvertent
operation of switches or worst case failures of any
kind in the alternator?
If the answer is "yes" then proceed to item 2. If the
answer is "no", then by all means, embrace suggestions
offered by the most persuasive proponents of alternative
solutions.
(2) There is an issue for at least some if not all IR
alternators being at-risk of damage due to b-lead
disconnection under load. This has several several
partial solutions:
(a) Placard the switch for no operation with the
engine running. This means the only time the alternator
would be subject to the load-dump event was during a
real ov event where disconnect was necessary and
protecting an already failed alternator from further
damage is a moot point.
(b) Add some measure of load-dump energy sink in the
form of "xxxx" . . . this might be an array of Transorbs
but they require sizing in very universal sense. If I
put Z-24 back in the book with transorbs across the
b-lead connection, I need to be convinced that this
solution is good for 99+ percent of all IR alternators
from which a builder might choose, INCLUDING those
fitted with non-OEM regulators.
(c) If (b) can be accomplished, then the prohibition
cited in (a) could be lifted as well. Data concerning
the nature of load-dumps was what I thought Paul was
going to investigate for us some time ago. After the
"investigation" was complete, no data was forthcoming,
only more cabbages and tomatoes.
(3) There is risk to any form of b-lead disconnect technology
to deal with the OV event. An alternator running at 10,000+
rpm has a rate-of-rise for open circuit voltage that's
spectacular. As contacts spread on the rudimentary
control contactor, it's possible (Paul says he's
demonstrated it) that an arc will form and not go out.
There are a couple of trade offs here too:
(a) If an energy-sink for the load-dump event can
be crafted as in 2(b), then the rudimentary contactor
is not at-risk for normal ON/OFF switching events.
The energy-sink would protect both the internal
regulator and the external control contactor from
undue stresses.
(b) if the energy-sink were in place, then the alternator's
output voltage would be limited by the energy-sink long
enough for any jelly-bean contactor to open relatively free of
arcing. After a period of time, one would then be
DELIGHTED if the current sink FAILED SHORTED. This
(ugh!) crow-baring of the b-lead to ground would deprive
the alternator of self-excitation and stall it. The
event would be over in a few seconds with high probability
that the alternator need only have a new regulator installed.
(c) One could install a contactor suited to the
high-voltage stress of the runaway alternator (killovac)
and simply allow the alternator to smoke its own field winding.
At least the OV event was prevented from propagating
to the rest of the airplane.
(4) Finally comes the issue of whether or not to install OV
protection:
(a) If you have a lot of faith in your alternator of
choice, then leave it off. You could install a high-voltage
warning light and depend on a well maintained battery to
keep bus votlage reasonably low (below 18v) long enough
to react and shut the alternator OFF. It would help
if energy sink 3(a) were in place to allow you to open
the plain vanilla contactor. Hopefully, the energy-sink
system will fail shorted and bring the whole event to
a happy conclusion. By the way folks, this is yet another
form of (ugh!) crowbar ov-protection . . . a system
DESIGNED to put a dead short on a line that needs to
be pulled down.
(b) If you choose to add ov protection, it's easily
accomplished with any number of products including the
OVM-14 crowbar module offered by B&C, Eric's passive
series switch design, etc. It doesn't matter. Any
of these technologies are subject to system integration
issues manifested by nuisance trips which may require
some attention on the part of the OV module supplier.
Okay, these are the ground rules for any solution I plan
to publish. The solution must come very close to meeting all
the design goals for staying within the historical paradigm
(but using modern components) that I cited at the outset
of this posting. I am not going to publish any suggestion
that there's a "golden" alternator or "golden contactor", etc
that will make this task easier. Offering such a limited solution
will get me a flood of e-mails and phone calls asking, "Gee,
I have this xxx alternator or yyy contactor, can you tell
me how to make it work too?" The new figure Z-24 needs to
accommodate ANY alternator, and any contactor one might
wish to use.
The answers to some of these questions still depend on access
to equipment I don't own but plan to. I'll invite anyone who
would like to participate (and perhaps even become a member
of the Hall of Fame) to post their offerings right here on the
list. We can all work together to craft test plans, provide
necessary materials and test equipment (hell, I'll mail
my pride-n-joy 'scope to someone who's adding to the collective
knowledge), and assistance in analysis of results with possible
changes to future tests.
Folks have suggested that my reluctance to recommend their
particular vision of the ultimate solution was in fact an
under-the-table condemnation of their solution. I hope
the foregoing discussion adequately dispels that notion.
It's been further suggested that I lack rudimentary skills
necessary for component design, system integration, failure
mode effects analysis, program management and delivery of
honorable services to a customer. Well, my answer is this:
The AeroElectric-List studies of Internally Regulated
Alternator Integration in Light Aircraft is open for
enrollment.
You may "audit" the class and simply watch what transpires, you
may participate with suggestions and questions that move the
effort forward and contribute to collective understanding,
or you may be an active participant in the much reviled
Repeatable Experiments by which we will show that the
products of our imaginations have a rightful place in the
real world of OBAM aircraft. Cabbage and tomato tossers need
not apply. If you want to play too, leave the vegetables
at home.
Let's begin with a requirements document. I'll formalize the
elements cited above into the opening paragraphs of the
requirements document. We can start thrashing from there.
Any suggestions? Did I miss anything? Got some ideas for
enhancements? Class is in session.
Question 1: Does anyone within a one-fuel tank range in
a Sundowner have access to a 2 hp or better, variable speed drive
stand capable of running an alternator with 2" pulley over
the range of 3000-11,000 rpm?
Bob . . .
________________________________________________________________________________
| From: | "Dave & Brenda Emond" <d_emond(at)mweb.co.za> |
| Subject: | Re: Plane-Power Alternator at OSH |
I did see that LAMAR Technologies has a Master Control unit available to
experimentals. OVP, VR, three buses, external power. This unit is apparently
std equip in all new Cessna's.
Dave Emond
40159
----- Original Message -----
From: "Tim Olson" <Tim(at)MyRV10.com>
Subject: AeroElectric-List: Plane-Power Alternator at OSH
>
> Did anyone else see the Plane-Power booth at OSH, right next to
> Sky-Tec and not too far from B&C?
>
> http://www.plane-power.com/
>
> I spent some time looking at their alternators, and was
> impressed enough that I signed up to hold show pricing
> when they're available, and so I can take time to learn
> more.
>
> They had a 70A FAA/PMA approved external regulated
> model, and a 60 and 70A internally regulated model,
> with OV protection (using the crowbar method). The
> price was right, and at least physicially I didn't see
> any issue. It was also interesting to hear that they
> went for full FAA/PMA approval on their alternator
> before they released any experimental alternators.
>
> I want to learn more about their OV module, as I'd
> have to assume that in order for them to put out this
> product, they must have done some testing to know what
> kind of failure damage is caused when the OV module trips.
> I didn't get enough time to gather my thoughts and ask
> every question I wanted...hoped maybe someone here could
> fill in some blanks.
>
> Also, they say that by next year, they want to have
> available an aux. alternator. I'm guessing that if I'm
> willing to delay that purchase, I could add it later
> and the total cost of my system would be WELL under
> 1/2 of my original plans.
>
> Their web page is still being built up, but here's a link
> to the 60A model. http://www.plane-power.com/AL12-EI60.htm
>
> Comments?
>
> --
> Tim Olson -- RV-10
>
>
>
________________________________________________________________________________
| From: | "Bill Denton" <bdenton(at)bdenton.com> |
| Subject: | Re: Audio Isolation Amp |
I have some questions regarding Bob's Audio Isolation Amp project...
Before getting into specifics, let me first ask a go-no go question:
I am looking for a "box" that will accept five mono inputs, and give one
mono output. It would be used to mix the outputs of two COMs plus the alarms
from some avionics devices, with the output to be fed to the COM input on an
intercom.
Is this feasible?
Now to some specific questions, assuming that what I am proposing is
feasible:
On the Parts List (Page 1.2), I notice that it refers to a:
9009-100-2 ECB ASSY - MONO ISO AMP
DIY FAB
and a:
9009-100-1 ECB ASSY - STEREO ISO AMP DIY
FAB
On the web site, the following product is listed: AEC9009-301-1. Which of
the above part numbers does this correlate to?
In comparing the SCHEMATIC - STEREO (Page 1.7) and the SCHEMATIC -
MONOPHONIC (Page 1.8), it appears that you can just build "half" the amp,
jumper Pins 2 and 3 where U114 would be, and use this as a mono unit. Is
this correct?
Would it be necessary to cut any of the traces on the circuit board? If yes,
where?
From NOTE 6. RESISTORS R103 THROUGH R107 ARE SELECTED TO EQUALIZE VOLUME
LEVELS BETWEEN AUDIO SOURCES. Could these be replaced with some type of
screwdriver adjustable pot to make it easier to balance the levels? If so,
what type/value/etc pot would be correct for this application? Could these
pots be mounted on the case so they would be externally adjustable?
Please feel free to add any additional information that I might have missed,
and thank you!
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: Alternator system design goals . . . |
Seems like a pretty good summary!
From my wishful thinking list, I'd also be happy if it could be shown
that a transorb array connected to the alternator output post would
short out sufficiently hard to cause battery current to trip a B-lead
fuse once a serious alternator runaway started. (ie. no B-lead contactor
needed).
Or I would be happy to cough up for a kilovac contactor if I was
convinced that is what it takes to reliably tame an OV. That might be
an acceptable fallback position for many folks.
Ken
>snip
>(4) Finally comes the issue of whether or not to install OV
> protection:
>
> (a) If you have a lot of faith in your alternator of
> choice, then leave it off. You could install a high-voltage
> warning light and depend on a well maintained battery to
> keep bus votlage reasonably low (below 18v) long enough
> to react and shut the alternator OFF. It would help
> if energy sink 3(a) were in place to allow you to open
> the plain vanilla contactor. Hopefully, the energy-sink
> system will fail shorted and bring the whole event to
> a happy conclusion. By the way folks, this is yet another
> form of (ugh!) crowbar ov-protection . . . a system
> DESIGNED to put a dead short on a line that needs to
> be pulled down.
>
>
________________________________________________________________________________
| From: | "DEAN PSIROPOULOS" <dean.psiropoulos(at)verizon.net> |
Eric is correct, my rant yesterday was a cheap-shot and I apologize. When I
started the rant my desire was to hopefully, motivate some people into
consolidating everything that has been said into a clear concise description
that we could all use. My excursion into Eric's business dealings was
uncalled for. One MIGHT infer from my comments that Mr. Jones is a
dishonorable person when in fact I have no evidence of that. I have never
dealt with the man on a business level. I INFERRED, (from comments made on
this list AND a request from Eric for the Wig Wag circuit design) that he
was capitalizing on other people's work and selling it as his own. I do NOT
for a fact, know this to be the case. Even if that were the case, it's not
illegal as long as the design data resides in the public domain or has
expired patents. If you are considering a purchase from him please don't go
somewhere else because of a few off-the-cuff comments I made on this list.
Talk to other people who have had dealings with the man and find out what
sort of business person he is. Then.MAKE YOUR OWN DECISION! And finally.I'd
like to apologize to the listers, instead of providing constructive
discourse, I opened my mouth and inserted my size 10 Nikes. In the future
I'll stick to technical questions and answers and not get caught up in the
"Venom Spewing". And yes Eric, I will cease and decist from using YOUR NAME
in MY POSTS from now on.
Dean Psiropoulos
RV-6A builder and occasional Nike chewer
-----Original Message-----
From: Eric M. Jones [mailto:emjones(at)charter.net]
Subject: Re: Alternators, OVP, GMCJET, Eric, Paul. OFFLIST
Dean,
I am trying to stay out of the innuendo and personal attacks on the
Aeroelectric List. You personally attacked me and I think you owe me an
apology. I don't think I did anything to merit your venom. Please leave my
name out of your posts on the Aeroelectric. If you have some personal
problem with me, please call.
Regards,
Eric M. Jones
www.PerihelionDesign.com
________________________________________________________________________________
| From: | GMC <gmcnutt(at)shaw.ca> |
| Subject: | Re: Painting Antenae |
Anyone have advice on repainting a ADF loop antenna. GPS, marker beacon
and fiberglass comm antenna should also be able to be rejuvenated, yes??
no??.
Thanks,
George in Langley BC
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
>
>
>Bob...,
>
>I'm building an RV-10 and started planning on using the Z-12
>architecture but I changed to Z-13/20 when it came out recently. Is it
>okay to use a B&C SB-1 standby regulator and a LR-3 instead of the
>two LR-3's shown in Z-13?
The SB-1 is specifically designed to autoswitch an
auxiliary alternator running on a common bus with
the main alternator. It's special features are not
needed in Z-13/20.
>With the battery behind the baggage compartment, I am running a 10awg
>wire for the battery buss alongside a 2awg for the alternator B lead.
> Is this a violation of not running fat and skinny wires together? Is
>there a guideline using the difference of awg of the wires that would help
>keep the fat
>wires away from the skinny wires? For example, if the difference in
>the awg sizes of the two wires is greater than 10awg sizes don't
>bundled them together.
Battery bus? Your battery bus is NOT right beside the
battery? Note the asterisk (*) on the wire segment between
the battery and any of the battery busses in Appendix Z.
This symbol indicates that these wires should be kept as
short as practical because they're major feeders and always
hot.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Alternator system design goals . . . |
>
>Seems like a pretty good summary!
>
> From my wishful thinking list, I'd also be happy if it could be shown
>that a transorb array connected to the alternator output post would
>short out sufficiently hard to cause battery current to trip a B-lead
>fuse once a serious alternator runaway started. (ie. no B-lead contactor
>needed).
Crowbaring the b-lead circuit protection (70A breaker/ANL limiter)
WOULD be a MAJOR event. The fusing constants for these devices
is large. However, in the early days of consideration for on-the-firewall
b-lead protection, the ANL hardware was set aside in favor of
some fast fuses suitable for bolting into the b-lead. See:
http://www.aeroelectric.com/Pictures/70-80fusekit.jpg
These fuses are quite fast . . . a feature that stirred up a
bit of a kerfuffle about 6 years ago on some list-server. See:
http://aeroelectric.com/articles/failtoll.pdf
I have pondered the hardware and energy studies for crowbaring
the b-lead of an IR alternator and opening a fast fuse.
Actually, the neatest way (lowest parts count) to run the
IR alternator would be to add a diode in series with the
alternator's output and crowbar the alternator itself to
ground without loading the ship's bus. The lights wouldn't
even flicker. Problem is that adding the diode tosses off
.5 to 1 volt of output. The voltage regulator inside the
alternator senses b-lead voltage, not control lead voltage.
Adding the diode would increment the bus voltage downward
and degrade battery recharging capability. If the designers
had only brought out a bus-sense terminal from the internal
regulator, this would be a no-brainer! The modern
IR alternator is a tantalizing challenge for doing the most
graceful system integration within the design goals I've
set for myself.
>Or I would be happy to cough up for a kilovac contactor if I was
>convinced that is what it takes to reliably tame an OV. That might be
>an acceptable fallback position for many folks.
I am confident that this will not be necessary. There
are numerous tradeoffs to be discovered and weighed
against each other. It's going to take some time. In
the mean time, anyone with Figure Z-24 installed is
encouraged to leave it in place for the moment. Don't
switch the alternator OFF with the engine running except
in case of problems. If you have a system that talks to
an OVM-14 crowbar module in ways that irritate it . . .
PLEASE let me know about it. We need the feedback and
we WILL fix all problems or give you your money back
or both.
I am reminded of some classroom challenges to deduce
the network of components inside a plastic box with
two leadwires coming out. You could use any manner of
test equipment to figure out what was inside and how it
was wired up. Our little IR alternator is a three-lead
device we cannot open and modify. They don't all work
the same way. The goal is to deduce a universal, minimum
parts count, maximum energy efficient way to make them
do electrical form-fit-function replacement of the machines we
grew up with. An interesting and doable endeavor, we
just need DATA.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <nuckollsr(at)cox.net> |
| Subject: | Re: Audio Isolation Amp |
>
>I have some questions regarding Bob's Audio Isolation Amp project...
>
>Before getting into specifics, let me first ask a go-no go question:
>
>I am looking for a "box" that will accept five mono inputs, and give one
>mono output. It would be used to mix the outputs of two COMs plus the alarms
>from some avionics devices, with the output to be fed to the COM input on an
>intercom.
>
>Is this feasible?
Yes . . .
>Now to some specific questions, assuming that what I am proposing is
>feasible:
>
>On the Parts List (Page 1.2), I notice that it refers to a:
>
> 9009-100-2 ECB ASSY - MONO ISO
> AMP DIY FAB
>
>and a:
>
> 9009-100-1 ECB ASSY - STEREO ISO
> AMP DIY FAB
>
>On the web site, the following product is listed: AEC9009-301-1. Which of
>the above part numbers does this correlate to?
Both. The 9009-300-1 ECB (item 1) is called out for both
versions of the isolation amplifier.
>In comparing the SCHEMATIC - STEREO (Page 1.7) and the SCHEMATIC -
>MONOPHONIC (Page 1.8), it appears that you can just build "half" the amp,
>jumper Pins 2 and 3 where U114 would be, and use this as a mono unit. Is
>this correct?
yes
>Would it be necessary to cut any of the traces on the circuit board? If yes,
>where?
no, if it were necessary, the instructions would be very
specific as to where.
> From NOTE 6. RESISTORS R103 THROUGH R107 ARE SELECTED TO EQUALIZE VOLUME
>LEVELS BETWEEN AUDIO SOURCES. Could these be replaced with some type of
>screwdriver adjustable pot to make it easier to balance the levels? If so,
>what type/value/etc pot would be correct for this application? Could these
>pots be mounted on the case so they would be externally adjustable?
You could. Some folks do use pot in their iso-amp products/designs.
The fixed resistors are much less expensive and more compact. I would
have to go to a larger box and I couldn't run the boards 2-up in
the fab process I'm using. Once the values are selected, they're
constant over the lifetime of the airplane. It's more fuss to set
it up but it won't need to be fiddled with again.
________________________________________________________________________________
| Subject: | Alternator system design goals . . . |
| From: | "Hinde, Frank George (Corvallis)" <frank.hinde(at)hp.com> |
I'm a little confused here.
Every IR alternator I have seen in my hot rod days had a voltage sensing
terminal. In my ND unit this is called the "s" terminal and is normally
wired to account for losses in the wiring (Van's doesn't use this
terminal in their standard setup)
Would this not take care of the forward loss thru the diode?
Crowbarring a 60A nominal alternator just feels little too "Robocop" for
an airplane application for me... Think I might stick with the Kilovolt
disconnect for the time being.
Gee maybe I could write a PHD theses on the phsychology of wiring
systems in aircraft...:)
Frank
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Robert L. Nuckolls, III
Subject: Re: AeroElectric-List: Alternator system design goals . . .
-->
>
>Seems like a pretty good summary!
>
> From my wishful thinking list, I'd also be happy if it could be shown
>that a transorb array connected to the alternator output post would
>short out sufficiently hard to cause battery current to trip a B-lead
>fuse once a serious alternator runaway started. (ie. no B-lead
>contactor needed).
Crowbaring the b-lead circuit protection (70A breaker/ANL limiter)
WOULD be a MAJOR event. The fusing constants for these devices
is large. However, in the early days of consideration for
on-the-firewall
b-lead protection, the ANL hardware was set aside in favor of
some fast fuses suitable for bolting into the b-lead. See:
http://www.aeroelectric.com/Pictures/70-80fusekit.jpg
These fuses are quite fast . . . a feature that stirred up a
bit of a kerfuffle about 6 years ago on some list-server. See:
http://aeroelectric.com/articles/failtoll.pdf
I have pondered the hardware and energy studies for crowbaring
the b-lead of an IR alternator and opening a fast fuse.
Actually, the neatest way (lowest parts count) to run the
IR alternator would be to add a diode in series with the
alternator's output and crowbar the alternator itself to
ground without loading the ship's bus. The lights wouldn't
even flicker. Problem is that adding the diode tosses off
.5 to 1 volt of output. The voltage regulator inside the
alternator senses b-lead voltage, not control lead voltage.
Adding the diode would increment the bus voltage downward
and degrade battery recharging capability. If the designers
had only brought out a bus-sense terminal from the internal
regulator, this would be a no-brainer! The modern
IR alternator is a tantalizing challenge for doing the most
graceful system integration within the design goals I've
set for myself.
>Or I would be happy to cough up for a kilovac contactor if I was
>convinced that is what it takes to reliably tame an OV. That might be
>an acceptable fallback position for many folks.
I am confident that this will not be necessary. There
are numerous tradeoffs to be discovered and weighed
against each other. It's going to take some time. In
the mean time, anyone with Figure Z-24 installed is
encouraged to leave it in place for the moment. Don't
switch the alternator OFF with the engine running except
in case of problems. If you have a system that talks to
an OVM-14 crowbar module in ways that irritate it . . .
PLEASE let me know about it. We need the feedback and
we WILL fix all problems or give you your money back
or both.
I am reminded of some classroom challenges to deduce
the network of components inside a plastic box with
two leadwires coming out. You could use any manner of
test equipment to figure out what was inside and how it
was wired up. Our little IR alternator is a three-lead
device we cannot open and modify. They don't all work
the same way. The goal is to deduce a universal, minimum
parts count, maximum energy efficient way to make them
do electrical form-fit-function replacement of the machines we
grew up with. An interesting and doable endeavor, we
just need DATA.
Bob . . .
________________________________________________________________________________
July 30, 2005 - August 10, 2005
AeroElectric-Archive.digest.vol-er