AeroElectric-Archive.digest.vol-ej
April 26, 2005 - May 10, 2005
from the battery it feeds -AND- the battery in the front.
ANL-30 or the modern, miniature automotive fuses could
be considered.
> I would prefer to have no fuse block behind the baggage bulkhead, I
>would like to run the 12 AWG feed to the firewall area where the other
>busses are.
>
>What is your opinion on the solid state power contactors offered by
>Perehelion in terms of reliabilty and suitability to the aircraft
>environment?
I don't know . . . and in view of recent mis-interpretations
of my statements I have to emphasize that when I don't KNOW
it's neither an endorsement or rejection of an idea or a product.
There ARE some really nice, hefty solid state devices available
that we could only dream about 30 years ago when you could sneeze
at a "power" transistor and reduce it to a blob of molten trash.
I was involved in the design of a solid state replacement
for contactors used in the tail de-ice system on a bizjet
a couple of years ago. Here's a couple of pictures of the
resulting product.
http://www.aeroelectric.com/Pictures/Solid_State_100A_Contactor.jpg
Bennie and I were talking about suggesting a new
environmental test for the next revisoin of DO-160.
We were going to call it the Chevy Suburban endurance
test.
http://www.aeroelectric.com/Pictures/Solid_State_Endurance.jpg
This critter is rated at 100A continuous and shuts off
to protect itself after 500 mS of 550 amps overload. So I can
tell you first hand that a clever designer can produce
some robust, no-moving parts designs. I'd like
to believe that Eric is a clever designer so I'd say
that the odds are very much in your (and his) favor.
I have a couple of designs I'm considering farming out
to a production activity. Nothing like a bit of
competition to keep the suppliers honorable and the
customers happy.
Bob . . .
________________________________________________________________________________
| From: | Rick Girard <fly.ez(at)verizon.net> |
| Subject: | Re: Autozone alternators |
Bob, All, Why not go to Rock Auto? Cheaper prices, even with shipping.
You will have to do a little research to get just what you want, but no
more than you would at Autozone.
http://www.rockauto.com/
Rick Girard
________________________________________________________________________________
| From: | "Bill Schlatterer" <billschlatterer(at)sbcglobal.net> |
| Subject: | Autozone alternators |
Geez, something I actually know about! Parts business guy! You didn't ask
the right question. AutoZone, just like NAPA, Advance, O'Reilly and even
the good ole Bumper to Bumper guys all sell several alternators at various
price points remanufactured by one of several folks. Yup, you guessed it.
Pay more get more. Not only that, but occasionally you actually get a "new"
product for rebuilt.
It used to be that there was a distinction between rebuilt and
remanufactured. Not so any more, all marketing hype. There are only a
handful of national manufacturers who can produce the volume for national
chains. These would be folks like DelcoRemy, Worldwide, AMP, Unit Parts,
etc. They produce and package it in a AZ box. The next run off the same
line goes in a NAPA box, CarQuest box, etc. No surprise, who fills the box
is a price quality trade-off. Also noted are many smaller regional
manufacturers who all produce at various levels of quality under not one but
usually 5 or 6 different brand names.
In most electrical reman facilities, they test everything that comes off the
line. Normal defective rates BEFORE they go out the door will run about 5%.
These are returned to the line and repaired again. Normal defective rates
on rebuilt/remain electrical will run 10-18% at the local parts store (these
are normal defective return rates, TRUE defective rates run 6% - 9%)
What goes in them? Some good stuff and some not so good. A new regulator
can cost from cents to a couple of bucks on the line but there is a huge
variance in where they come from. Stuff from the Pacific Rim is much
cheaper and usually but not necessarily inferior. Who knows at the local
level what goes in them,.... nobody!
Next question is what is in the box? The reason AutoZone brands their
product is kinda obvious for "marketing" but not so obvious is that they can
switch brands, quality, manufacturers, etc at will and you will never know
it. This is not unique to AZ, it's the way all private branded parts
packaging works. It's that way on purpose.
Next questions is "where" is what is in the box? Because of the problem
with handling cores (two ways) and the weight of the products which results
in high freight costs, you have no guarantee that what is in the AZ or NAPA
or CarQuest(choose any)box is the same in California as it would be in
Florida. This is just the business and nothing wrong with it! EXCEPT if
you want to really know what is in the box and I promise that the average
guy on the parts counter can't tell you any more than is written on the box.
This means "new regulator" but does not mean "quality regulator". Maybe or
maybe not!
The ONLY way you know about the quality of a reman alternator is to know the
guy that built it and know what he is using, or rely on the price point as
an assurance of "quality". Just remember that there are various levels of
"good".
What do you get with B&C? Who knows, BUT, they know where the buy parts,
they know they check the balance, they field test the unit AGAIN, remember
5% defects right off the line, and they know the specs on their regulators.
If you don't have a local rebuilder who knows what he is doing rebuild the
unit, you really just don't know what is in the box. B&C is the rebuilder
and we all trust them to put out a better than "good" product in every box.
Good news! Virtually any good parts store has a "best" quality line that
will have "good" quality parts but don't delude yourself into thinking that
a cheap one is as good as a more costly version just because both are
"tested" and use "new" replacement parts. They will all give good service
in average conditions with a good battery.
From my perspective, B&C is the quality inspection guy! They do know what
is in the box because they put it there.
YMMV
Bill S
7a Ark
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Hinde,
Frank George (Corvallis)
Subject: AeroElectric-List: Autozone alternators
So does anyone have any input specifically on Autozone rebuilt
alternators?
I don't have enough data to say whether I should go get a refun on my
Camry ND unit.
Thanks
Frank
________________________________________________________________________________
| From: | B Tomm <fvalarm(at)rapidnet.net> |
| Subject: | basic reasoning for system architecture |
If it's a battery the same size as the main battery, then it would
sure be NICE to use it for cranking assistance . . . hard to
do with 12AWG feeders.
Yes the battery would be the same size but not for the reason of cranking
power. If the engine battery won't start it, I really don't want it onboard
even with a backup battery (electrically dependant engine). The front
battery would be the easy one to get at for a change or to remove for
charging.
. That's another mis-interpretation of my writing
when I suggest something. EVERY architecture is based on certain
DESIGN GOALS from which REQUIREMENTS are developed and a solution
deduced. Everyone is encouraged to develop their own design
goals and then drive toward their own solution. Folks often
believe that what I publish is based on some kind of REQUIREMENT
when in fact, the only requirements are those which you place
on the project yourself. My goal is to impart sufficient understanding
that new architectures don't add complexity without also adding
value.
Actually I, as I'm sure many others also, don't view your stuff as based on
some kind of requirement. On the contrary I see the obvious experience and
thought behind the theory and architecture. This keeps me learning in the
learning/absorbing mode. As the student, I look to the teacher as
somewhat of an authority. Trying to understand his material but not
questioning/criticizing every detail needlessly. I've been on this list
for quite some time and started with no knowledge of "aircraft electrical
systems". Yesterday I couldn't even spell aveeyawnix tacknotion, but now,
I think I have a pretty good understanding of the basics for what my system
needs. Enough to order a bunch of electrical components today. That said
I must have learned something because I'm not one to gain confidence
without understanding.
Yeah, in fact you might consider something just a tad heavier
like 10 or 8AWG. Unlike the FAT feeders, these smaller wires
are certainly more subject to gross failure under the
hard-fault condition. I think I'd put the battery bus
back at the battery location so each of the feeders
extending from the battery are protected. I'd have a
battery "contactor" which might be a fat relay but the
plain vanilla, Stancore/White-Rogers/Cole-Hersee parts
would be just fine too. You'd want to protect the small
feeder at both ends . . . it's subject to energy coming
from the battery it feeds -AND- the battery in the front.
ANL-30 or the modern, miniature automotive fuses could
be considered.
I would have thought of that...eventually, really!!! Thanks
>What is your opinion on the solid state power contactors offered by
>Perehelion in terms of reliabilty and suitability to the aircraft
>environment?
I don't know . . . and in view of recent mis-interpretations
of my statements I have to emphasize that when I don't KNOW
it's neither an endorsement or rejection of an idea or a product.
There ARE some really nice, hefty solid state devices available
that we could only dream about 30 years ago when you could sneeze
at a "power" transistor and reduce it to a blob of molten trash.
"Don't know" is a perfectly acceptable answer. Yeah we understand that
you're human, BUT you know more about most of this stuff than most (if not
all) of us first time builders. In other words, even your opinions are
well respected here. I could ask the manufacturer, but a third party's
opinion without a vested interest has a different value.
I have a couple of designs I'm considering farming out
to a production activity. Nothing like a bit of
competition to keep the suppliers honorable and the
customers happy.
The future is bright indeed. Now if we could only find a solution to the
rising costs of avgas...
Bevan
________________________________________________________________________________
| From: | "Chris & Kellie Hand" <ckhand(at)earthlink.net> |
| Subject: | Re: Internally regulated alternator OVP protection |
Ken & Bob,
Thanks for the education...and at the risk of sound a little EE-ignorant, I
hope you don't mind a few follow up questions:
When you say you've replaced a few similar shorted transistors, are you
talking about replacing ICs due to short type faults (how could you tell?),
or are you talking about a failed stand-alone single transistor in a ckt?
Do you consider transistors in an IC ckt (such as those used in an I-VR) to
be any more or less likely to short than single device transistors in a
standard built up ckt? Or is there any way to know/quantify the difference
in reliability?
Are you saying it's not possible to design ICs for I-VRs without having a
single point failure mode, or is your position based on assuming that most
are designed with a single point failure mode (or you can't tell)?
Thanks again,
Chris
----- Original Message -----
From: "Robert L. Nuckolls, III protection" <b.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Re: Internally regulated alternator OVP
protection
protection
>
>
> >
> >Hi Chris
> >
> >If the field driver shorts (part MTB20N20E in your first reference or
> >part 2N6284 in your second reference) then there is no way that I can
> >see for the referenced devices to stop an over voltage. How likely is
> >that - I don't know but I have replaced a few similar 'transistors' that
> >were indeed shorted in other equipment over the years.
>
> Hear hear! This is exactly the simple-idea upon which
> the notion of additional OV protection and/or external
> control by means of switch on panel is based. Every alternator
> has some sort of solid state device in series with the field
> with a responsibility to modulate field current in response
> to regulator commands for voltage control. If that puppy
> fails shorted -OR- gets an uncontrolled ON-command from
> failed circuitry elsewhere, the alternator's voltage is
> officially out of the gate and racing for the moon.
>
> >If a separate external OVP device fails to work when it should then we
> >have two separate devices failing simultaneously which is pretty rare.
> >We can't test the functionality of an OVP internal to an alternator but
> >we can test the separate OVP device if we so desire.
>
> Dead-on . . .
>
>
>
> >FWIW my feeling is that yes external ov protection is a good thing on an
> >IR alternator but not essential for most of us. I suspect that it will
> >indeed decrease overall system reliability and I doubt very much whether
> >that is going to be quantified on this forum. However I also believe it
> >reduces risk to my brand new icomm A-200 transceiver that still warns
> >that over 16 volts will kill it and that it must be turned off during
> >engine starting... (%$#%) I did add the transorbs to the alternator
> >side of the my ov contactor to increase the likelihood of the contactor
> >working as desired. And I'm still happy with my decision to not route
> >the alternator B-lead through a battery master.
>
> Which goes to another post of mine that speaks to design goals. There
> are no REQUIREMENTS that any of us can levy upon the wishes
> and goals of any other builder. Lots of folk are tightly
> wrapped around an axle assuming that what I write has
> come manner of social design goal to control or set requirements
> on other people's actions.
>
> Ken is demonstrating a high level of understanding that
> would assuage any concerns I might have should I have
> an opportunity to ride with him in his airplane.
>
> This kind of conversation is what makes the AeroElectric-List
> an arena of ideas as opposed to a barroom brawl over who
> is trying to control whom.
>
> Bob . . .
>
>
________________________________________________________________________________
| From: | owner-aeroelectric-list-server(at)matronics.com |
| Subject: | Re: Rebuilt versus Original |
Grist for your mill - and digressing somewhat off subject.
Legend has it that Henry Ford used to go to junk yards and looked at parts
in his junked cars. If the parts had still a lot of life in them, then they
were overbuilt quality wise. He would take the part to design and
manufacturing and had quality, hence costs, reduced.
So, new is not necessarily better than rebuilt - all depends as to who does
the rebuilding.
I'll add to that, with today's blossoming counterfeit parts being proposed
at low prices, new can indeed be very bad.
Michele
RV8 - fuselage
> -----Original Message-----
> From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-
> aeroelectric-list-server(at)matronics.com] On Behalf Of Eric M. Jones
> Sent: Wednesday, April 27, 2005 12:37 AM
> To: aeroelectric-list(at)matronics.com
> Subject: AeroElectric-List: Re: Rebuilt versus Original
>
>
>
> There has been some disparagement of rebuilt equipment recently--so I
> think
> we should set the record straight.
>
> Is original stuff better than rebuilt?
>
> Original equipment is "good enough" for the task, and task is mainly to
> satisfy the customer until the warranty expires. I'm not being cynical
> here.
> Since the huge production volumes are sensitive to costs, nothing that is
> better than what-is-needed-to-satisfy-the-task is required. In fact to do
> anything else would be throwing money away. My Dad showed me how American
> machine tools made in 1941 would have the sharp edges INSIDE castings
> smoothed down while the same machine made a few months later would not.
> The
> task had changed.
>
> It is also true in some assembly operations that a part which goes into an
> assembly may have inspections and tests done on it which a part destined
> for
> the new original stock (but not used in an assembly) never has to undergo.
> A
> part that comes out of a box may indeed be inferior to a part out of a
> junkyard in these instances. Selling slightly not-so-good parts in the
> aftermarket is common.
>
> But let's look at original and rebuilt alternators.
>
> Mythical rebuilding operation: Starting with a "core", the alternator is
> disassembled. All the fasteners and bearings are thrown away and new ones
> are used. The bearings can be of better quality than original. The case,
> rotor and stator are inspected and cleaned up. Often new, higher
> voltage-withstand diodes are retrofitted, new brushes are added. Often a
> new
> regulator assembly (incorporating the newest electronics) is fitted.
> Everything is inspected, torqued, fitted, and sometimes, YES (per B&C,
> thanks Bill...) even dynamically balanced.
>
> Is this better than new? Probably so....In many cases it certainly is.
> Offer
> to take the rebuild shop owner up in your airplane. Watch his reaction.
>
> Regards,
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge MA 01550-2705
> Phone (508) 764-2072
> Email: emjones(at)charter.net
>
> Teamwork: " A lot of people doing exactly what I say."
> (Marketing exec., Citrix Corp.)
>
>
>
>
>
________________________________________________________________________________
| Subject: | A 380 first flight |
Hi all,
Now live at
http://www.airbus.com/A380/Seeing/live/video/live.asx
Regards,
Gilles Thesee
Grenoble, France
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: Internally regulated alternator OVP protection |
Chris & Kellie Hand wrote:
>
>Ken & Bob,
>Thanks for the education...and at the risk of sound a little EE-ignorant, I
>hope you don't mind a few follow up questions:
>
>When you say you've replaced a few similar shorted transistors, are you
>talking about replacing ICs due to short type faults (how could you tell?),
>or are you talking about a failed stand-alone single transistor in a ckt?
>
>
I don't do a lot of electronics repair but I was referring to discrete
power transistors with similar part numbers to the ones shown in the
diagrams you referenced. They are often the hottest component in
circuitry and depend on good assembly to heat sinks etc. The last one
that I replaced was in a $1500. amplifier that the high school was going
to scrap. It was one of eight similar transistors and it failed shorted
and blew the power fuse because the factory had overtightened and
stripped the screw fastening it to a heat sink seven years previously.
The manufacturer was happy because it survived the warranty and they
would make a new sale. My point is merely that such components do at
least sometimes fail shorted or fail such that they could cause the
alternator to run at maximum output.
>Do you consider transistors in an IC ckt (such as those used in an I-VR) to
>be any more or less likely to short than single device transistors in a
>standard built up ckt? Or is there any way to know/quantify the difference
>in reliability?
>
>
For several reasons my limited experience suggests that IC's are
generally more reliable, especially if they are installed by automated
machinery. I don't think it matters to us though.
>Are you saying it's not possible to design ICs for I-VRs without having a
>single point failure mode, or is your position based on assuming that most
>are designed with a single point failure mode (or you can't tell)?
>
It can certainly be done but it raises all kinds of related issues and
it raises the price. In the case of our alternators it is difficult to
tell but the circuitry that is normally published would suggest that
most do have a single point of possible failure. When you design and
build an IC it may cost very very little to incorporate additional ov
protection or to provide better input and output protection on a single
piece of silicon (It is still on one piece of silicon but lets ignore
that). But if the IC controls one power transistor then you still have a
one point failure mode. Does it matter - I don't know. Add another power
transistor and you can fix that but again system reliability probably
goes down and costs go up. So I'd expect to see only one power
transistor but perhaps a few extra cents spent to raise its quality
such that it almost never fails, and I think that is the common state of
the art... This is speculation though.
More pertinent and as has been pointed out by others, it is not in the
manufacturers best interest to make alternators that never fail. It is
in their interest to make alternators that fail passively by ceasing to
produce power rather than going overvoltage and killing other expensive
computers and such. I think that is the main point that proponents of
using a NEW MODERN IR alternator are making and I think it has merit.
But to have some fun, it's not totally inconceivable that some
automotive ecu's could shutdown the engine to protect itself if it
detects an extended overvoltage! Overspeed protection is pretty common
in ecu's. As is reduced power limp home modes. Why not protection from
extended overvoltage ? ;) Years of watching automotive conversions have
taught me to be cautious about applying automotive reliability to
aircraft. Many things such as that battery master, different types and
sizes of batteries, alternator location, or one off wiring, may make it
irrelevant to us. Failures of automotive conversions are given little
publicity and electrical issues are not uncommon. I am doing a
conversion myself - but someone saying that this or that component never
fails in a car means little to me. I like Bob's philosophy of making
failures a non-event!
Ken
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Contact Arc Suppression |
>
>The automotive industry has been moving gung-ho towards 42 volt systems. The
>gung-ho slowed considerably when it was generally appreciated that there was
>no way to make a contact arc extinguish reliably. This could lead to
>horrendous consequences where switches or relays were opened and the current
>just continued in a bright arc until something melted into a puddle. The
>progress towards 42 volt is now more tentative.
Hadn't heard about this "stumbling block" . . . I just assumed that
part of the 42v development goals would be to eliminate mechanical
switches . . . solid state devices don't arc (they've got other
vulnerabilities to the same stresses however).
>A standard B+ contactor for disconnecting the alternator in the case of an
>alternator runaway may not work if the contactor is suddenly presented with
>a voltage much above 13-16 VDC, because the arc may not extinguish.
The territory just above 16v isn't the edge of the earth . . . the
dielectric strength of air is about 1000v/mil . . . but how far apart
are contacts of a switch when they first open? Micro-inches, nano-inches,
pico-inches? How much voltage does it take to jump damned few inches?
Damned few volts. So every set of contacts that open under any
circumstances
for current flow and system voltage WILL arc.
Contact mass, spreading velocity, arc source rise time and ultimate limits
to open circuit amplitude in both voltage and energy are key players and
tightly interlinked.
One can mitigate an arcing situation with any combination of adjustments
to these effects. For the past few months, transorbs have been under
discussion
as means by which ultimate voltage and total energy available to feed
an arc
can be brought to heel. Contactors and switches can be selected or modified
to improve on resistance to arcing under conditions presented by the
system.
Of particular interest to me right now is the capability of a
Stancore/White-Rogers/
RBM Controls generic contactor to disconnect an internally regulated
alternator
after it's well into the self destructive cycle of a regulator failure.
Here
we know that transorbs won't help . . . they're for transient,
relatively low
energy events. The runaway alternator is not transient. It goes on
until something
shuts it down (difficult from the outside on an internally regulated
alternator),
or it destroys itself. The best we can hope for with incorporation of a
b-lead
contactor is that we can effectively disconnect it from the rest of the
airplane.
Here, the event isn't "just above 16" or even 32 volts (general rating for
contacts in this product) but well over 100 volts.
>Arcing of contacts is typical of DC systems with voltages much higher than
>standard automotive voltages.
I'd caution the use of "standard" in this context. Boats, railroads,
wind driven generators on farms have used 18-cell (36v battery/42 volt)
systems for nearly 80 years and they all had to learn to live with
the task of making and breaking circuits.
>A huge amount of engineering has gone into
>making contacts survive. Many engineers have spent their entire career on
>the subject.
Absolutely! The volumes of data available on contact science is
staggering. Just consider this alternator regulator from Ford
circa 1960.
http://www.aeroelectric.com/Pictures/Ford_EM_Reg.jpg
http://www.aeroelectric.com/Pictures/Ford_EM_Reg_Volage_Relay.jpg
http://www.aeroelectric.com/Pictures/Ford_EM_Reg_Field_Relay.jpg
Here's a set of contacts that had to switch the most inductive
load in a vehicle (alternator field) hundreds of times per
second for thousands of miles of operation of the vehicle.
No transorbs were available at the time. However, both regulation
dynamics and contact life were enhanced by putting some constant
ON bias to the alternator field with a resistor visible here:
http://www.aeroelectric.com/Pictures/ALTREG6.JPG
While this helped, designers still had to depend on VERY hard
contact material common to distributor points and copper-n-steel
regulators that dated back to the 1920s.
> A couple years ago Tyco engineers looked at the problem and
>someone decided that this was a perfect application for their Polyswitch.
>
>The Tyco refs are:
>http://www.circuitprotection.com/appnotes/AppNote_42V_PR.pdf
>
>Remarkably, if you choose the right polyswitch there is NO CONTACT ARC AT
>ALL.
Interesting application for this device. Pretty slick.
>To explain how this can be
>http://www.periheliondesign.com/downloads/Polyswitch.pdf --imagine a
>Polyswitch across the contacts, in parallel with the contact gap. I have
>used a relay to illustrate this, but it works the same in switches and
>connectors. Everything is OFF. The Polyswitch in its OFF condition has a
>very low resistance, thus for an instant the Polyswitch actually conducts
>before going into its high resistance mode. (This is not optimal in all
>circumstances but we can examine it later).
>
>When the relay is energized, the contacts close. As a general rule, this
>does not cause arcing below 330 volts or so. The Polyswitch is now shorted
>or bypassed by the path through the relay contacts. As a consequence, the
>Polyswitch goes cold and reverts to its Low Resistance state.
Hmmm . . . I've worked dozens of contact life issues on the airplanes'
over the years and virtually ALL of them had issues based on contact
closure (bounce) and downstream loads (lamp loads, reactive loads due
to combined effects of shielded wire and radio filter capacitors, etc).
None had issues with respect to arcing on contact opening.
>When the relay is turned off, the Polyswitch is still shorted across the
>contact gap, and as a result, prevents any contact arcing. In an instant the
>Polyswitch heats up and goes into its high resistance state--thus turning
>off the circuit.
>
>There will be more on this as time allows, but the key point here is that
>the B+ contactor should probably be equipped with such a scheme to ensure
>that the B+ line is really cut off. Contactors, relays, connectors, and
>switches will last about forever with such a scheme.
Don't know about forever but it will indeed be a quantum jump in
service life.
>Caveat: Nobody said it was easy. Some selection of the proper part is
>required. Perhaps some experimenting needs doing.
>
>If you are not convinced that this is a good idea I suggest some reading
>about the micro-details of how contacts open. Terrifying reading!
>http://relays.tycoelectronics.com/app_pdfs/13c3203.pdf
>
>Finally please note the bi-directional transorbs across the coils.
I read this article. It's generally factual but contains
a lot of non-quantified conditions. Further, it's got some
fundamental problems with their description of contact physics.
For example, the authors allude to a 'breakover voltage' depending
on contact material to wit:
Different contact materials have different arc voltage ratings. For fine
silver, the arc voltage is 12 volts. For cadmium, it is 10 volts; and for gold
and palladium it is 15 volts. Let's assume the contacts are fine silver.
Within nanoseconds after the molten bridge explodes, if the material is
silver and if circuit voltage is 12 volts or more, voltage breakover occurs.
If circuit voltage is less than 12 volts, breakover cannot occur and there
will be no arc.
Hmmmm . . . . the dielectric strength of air is about 1000v/mil.
What is the gap between contacts when they FIRST open? Nano
inches? Picoinches? Damned small inches. This suggests the
the potential for establishing an arc across spreading
contacts with damned small volts as well. Quoting from some
Honeywell-Microswitch documents on contact and switch physics . . .
During contact bounce on closure, molten metal splashes. As the contacts
separate to open the
circuit, arcing occurs again. Meanwhile, things are happening on the atomic
scale. As the
contacts begin to separate, a bridge of molten metal is drawn between them.
As it ruptures, it may
leave more metal on one contact than on the other. This is called bridge
transfer and opinions
differ as to exactly how it occurs. A short arc is drawn as the bridge
breaks. Electrons emitted
from the negative terminal (cathode) cross the gap without interference
(the gap at this time is
too short to contain many gas atoms) and bombard the positive terminal
(anode). Their high
energy causes ionization of some of the surface atoms of the anode
terminal. The resulting
positive ions of negative contact material are repelled by the anode and
attracted to the cathode.
Thus, metal is moved from anode to cathode. As the contacts continue to
separate, a phenomenon
occurs which moves material in the opposite direction in the form of vapor
and continues until
the contacts are about 4 microns apart (assuming silver contacts in air).
As the contacts continue to separate, a significant amount of electron
avalanching begins and a
plasma of ionized gas develops. The gap becomes wide enough to contain an
appreciable amount
of ambient gas. Electrons emitted by the cathode strike gas atoms, losing
some of their energy in
the process, ionizing some of the gas atoms and thus releasing more
electrons. The electrons
reaching the anode have such low energy that ionization of the anode
practically stops. Pressure
of the metal vapor in front of the cathode is higher than that in front of
the anode, and the
pressure differential draws a jet of metal vapor from the cathode. The jet
strikes the anode and
the vapor condenses there. This is called plasma arc transfer and causes
migration of metal from
cathode to anode.
Wow! Things are starting to happen at 4 microinches of separation.
If your interested in having these documents they can be
acquired from the reference docs page on my website at:
http://aeroelectric.com/Reference_Docs
Go to the Microswitch folder and download the two .pdf files.
The most striking feature of the article is lack of depth with
respect to contact life issues. For example.
Here's a 5A relay that has been qual tested to over 100,000 cycles
at full load.
http://www.aeroelectric.com/Pictures/MaintRelay_D.jpg
Looks pretty bad . . . but it STILL met requirements for normal
operations.
Now look at this relay:
http://www.aeroelectric.com/Pictures/1_B30K3_stick.jpg
This relay was sticking at less than 30,000 cycles and was
a player in a trim runaway scenario. Part of what drove the
sticking phenomenon was contact bounce and downstream
conditions in the system which was documented here:
http://www.aeroelectric.com/Pictures/4_bounce500Knocap1.gif
EVERY time the high failure rate relay closes, it takes
4-8 hits. Another brand of relay qualified to the same
spec only bounces 2-3 times and had less than 1/10th the
failure rate. This has nothing to do with presence
or lack of arc suppression across the coil and little to
to with textbook loading conditions.
The article isn't "wrong" but it's very textbookish in
and simply regurgitates a lot of standard stuff on contact life,
most of which doesn't apply to light aircraft that fly an
average of 50 hours a year. When I encounter relay and switch
problems on airplanes, these are generally machines that fly
hundreds of hours per year . . . and the root cause is almost
never based on poor switch selection or failure to observe
ratings.
I'd advise caution before one reacts to this article as
a basis for making design decisions . . . I've not researched
the article in detail but it has some serious holes in the
facts and logic.
Bob . . .
________________________________________________________________________________
| Subject: | Autozone alternators |
| From: | "Hinde, Frank George (Corvallis)" <frank.hinde(at)hp.com> |
Wow...So I guess I'll fit the alternator and see if it dies?....Would
you guys add the OVP as an external protection device just to be safe?
What do you all think?
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Bill
Schlatterer
Subject: RE: AeroElectric-List: Autozone alternators
-->
Geez, something I actually know about! Parts business guy! You didn't
ask the right question. AutoZone, just like NAPA, Advance, O'Reilly and
even the good ole Bumper to Bumper guys all sell several alternators at
various price points remanufactured by one of several folks. Yup, you
guessed it.
Pay more get more. Not only that, but occasionally you actually get a
"new"
product for rebuilt.
________________________________________________________________________________
| From: | rv-9a-online <rv-9a-online(at)telus.net> |
| Subject: | Re: Contact Arc Suppression |
Hmmm. Back when I was blowing up power transistors for a living :-) , I
had to quickly learn about SOA (Safe Operating Area) of semiconductor
devices.
Switching off any load, especially inductive loads, can overstress
electronic devices unless explicit steps are taken to prevent it. It
appears that the exact analogy exists for mechanical contacts. A
particular contact (switch, relay, contactor) will have a manufacturer's
specified SOA... a combination of dynamic voltage and current conditions.
The 'fix' I used for transistors was called a snubber circuit: a
resistor and capacitor in series connected from the collector to
emitter. In a switching power supply, this get's very warm so component
selection was important. In an aircraft, a snubber circuit would only
have to handle instantaneous power, but the average power would be very
low.
The Polyswitches are fancy snubbers, and my opinion is that they are not
foolproof.
My question to Bob is: do you have any experience with prevention of
contact welding by using R-C snubbers?
Vern Little RV-9A
Robert L. Nuckolls, III wrote:
>
>
>
>
>>
>>The automotive industry has been moving gung-ho towards 42 volt systems. The
>>gung-ho slowed considerably when it was generally appreciated that there was
>>no way to make a contact arc extinguish reliably. This could lead to
>>horrendous consequences where switches or relays were opened and the current
>>just continued in a bright arc until something melted into a puddle. The
>>progress towards 42 volt is now more tentative.
>>
>>
>
> Hadn't heard about this "stumbling block" . . . I just assumed that
> part of the 42v development goals would be to eliminate mechanical
> switches . . . solid state devices don't arc (they've got other
> vulnerabilities to the same stresses however).
>
>
>
>
>>A standard B+ contactor for disconnecting the alternator in the case of an
>>alternator runaway may not work if the contactor is suddenly presented with
>>a voltage much above 13-16 VDC, because the arc may not extinguish.
>>
>>
>
> The territory just above 16v isn't the edge of the earth . . . the
> dielectric strength of air is about 1000v/mil . . . but how far apart
> are contacts of a switch when they first open? Micro-inches, nano-inches,
> pico-inches? How much voltage does it take to jump damned few inches?
> Damned few volts. So every set of contacts that open under any
>circumstances
> for current flow and system voltage WILL arc.
>
> Contact mass, spreading velocity, arc source rise time and ultimate limits
> to open circuit amplitude in both voltage and energy are key players and
> tightly interlinked.
>
> One can mitigate an arcing situation with any combination of adjustments
> to these effects. For the past few months, transorbs have been under
>discussion
> as means by which ultimate voltage and total energy available to feed
>an arc
> can be brought to heel. Contactors and switches can be selected or modified
> to improve on resistance to arcing under conditions presented by the
>system.
>
> Of particular interest to me right now is the capability of a
>Stancore/White-Rogers/
> RBM Controls generic contactor to disconnect an internally regulated
>alternator
> after it's well into the self destructive cycle of a regulator failure.
>Here
> we know that transorbs won't help . . . they're for transient,
>relatively low
> energy events. The runaway alternator is not transient. It goes on
>until something
> shuts it down (difficult from the outside on an internally regulated
>alternator),
> or it destroys itself. The best we can hope for with incorporation of a
>b-lead
> contactor is that we can effectively disconnect it from the rest of the
>airplane.
>
> Here, the event isn't "just above 16" or even 32 volts (general rating for
> contacts in this product) but well over 100 volts.
>
>
>
>
>>Arcing of contacts is typical of DC systems with voltages much higher than
>>standard automotive voltages.
>>
>>
>
> I'd caution the use of "standard" in this context. Boats, railroads,
> wind driven generators on farms have used 18-cell (36v battery/42 volt)
> systems for nearly 80 years and they all had to learn to live with
> the task of making and breaking circuits.
>
>
>
>>A huge amount of engineering has gone into
>>making contacts survive. Many engineers have spent their entire career on
>>the subject.
>>
>>
>
> Absolutely! The volumes of data available on contact science is
> staggering. Just consider this alternator regulator from Ford
> circa 1960.
>
>http://www.aeroelectric.com/Pictures/Ford_EM_Reg.jpg
>http://www.aeroelectric.com/Pictures/Ford_EM_Reg_Volage_Relay.jpg
>http://www.aeroelectric.com/Pictures/Ford_EM_Reg_Field_Relay.jpg
>
> Here's a set of contacts that had to switch the most inductive
> load in a vehicle (alternator field) hundreds of times per
> second for thousands of miles of operation of the vehicle.
> No transorbs were available at the time. However, both regulation
> dynamics and contact life were enhanced by putting some constant
> ON bias to the alternator field with a resistor visible here:
>
>http://www.aeroelectric.com/Pictures/ALTREG6.JPG
>
> While this helped, designers still had to depend on VERY hard
> contact material common to distributor points and copper-n-steel
> regulators that dated back to the 1920s.
>
>
>
>> A couple years ago Tyco engineers looked at the problem and
>>someone decided that this was a perfect application for their Polyswitch.
>>
>>The Tyco refs are:
>>http://www.circuitprotection.com/appnotes/AppNote_42V_PR.pdf
>>
>>Remarkably, if you choose the right polyswitch there is NO CONTACT ARC AT
>>ALL.
>>
>>
>
> Interesting application for this device. Pretty slick.
>
>
>
>
>>To explain how this can be
>>http://www.periheliondesign.com/downloads/Polyswitch.pdf --imagine a
>>Polyswitch across the contacts, in parallel with the contact gap. I have
>>used a relay to illustrate this, but it works the same in switches and
>>connectors. Everything is OFF. The Polyswitch in its OFF condition has a
>>very low resistance, thus for an instant the Polyswitch actually conducts
>>before going into its high resistance mode. (This is not optimal in all
>>circumstances but we can examine it later).
>>
>>When the relay is energized, the contacts close. As a general rule, this
>>does not cause arcing below 330 volts or so. The Polyswitch is now shorted
>>or bypassed by the path through the relay contacts. As a consequence, the
>>Polyswitch goes cold and reverts to its Low Resistance state.
>>
>>
>
> Hmmm . . . I've worked dozens of contact life issues on the airplanes'
> over the years and virtually ALL of them had issues based on contact
> closure (bounce) and downstream loads (lamp loads, reactive loads due
> to combined effects of shielded wire and radio filter capacitors, etc).
> None had issues with respect to arcing on contact opening.
>
>
>
>
>>When the relay is turned off, the Polyswitch is still shorted across the
>>contact gap, and as a result, prevents any contact arcing. In an instant the
>>Polyswitch heats up and goes into its high resistance state--thus turning
>>off the circuit.
>>
>>There will be more on this as time allows, but the key point here is that
>>the B+ contactor should probably be equipped with such a scheme to ensure
>>that the B+ line is really cut off. Contactors, relays, connectors, and
>>switches will last about forever with such a scheme.
>>
>>
>
> Don't know about forever but it will indeed be a quantum jump in
> service life.
>
>
>
>
>>Caveat: Nobody said it was easy. Some selection of the proper part is
>>required. Perhaps some experimenting needs doing.
>>
>>If you are not convinced that this is a good idea I suggest some reading
>>about the micro-details of how contacts open. Terrifying reading!
>>http://relays.tycoelectronics.com/app_pdfs/13c3203.pdf
>>
>>Finally please note the bi-directional transorbs across the coils.
>>
>>
>
> I read this article. It's generally factual but contains
> a lot of non-quantified conditions. Further, it's got some
> fundamental problems with their description of contact physics.
> For example, the authors allude to a 'breakover voltage' depending
> on contact material to wit:
>
>
>Different contact materials have different arc voltage ratings. For fine
>silver, the arc voltage is 12 volts. For cadmium, it is 10 volts; and for gold
>and palladium it is 15 volts. Let's assume the contacts are fine silver.
>Within nanoseconds after the molten bridge explodes, if the material is
>silver and if circuit voltage is 12 volts or more, voltage breakover occurs.
>If circuit voltage is less than 12 volts, breakover cannot occur and there
>will be no arc.
>
> Hmmmm . . . . the dielectric strength of air is about 1000v/mil.
> What is the gap between contacts when they FIRST open? Nano
> inches? Picoinches? Damned small inches. This suggests the
> the potential for establishing an arc across spreading
> contacts with damned small volts as well. Quoting from some
> Honeywell-Microswitch documents on contact and switch physics . . .
>
>
>During contact bounce on closure, molten metal splashes. As the contacts
>separate to open the
>circuit, arcing occurs again. Meanwhile, things are happening on the atomic
>scale. As the
>contacts begin to separate, a bridge of molten metal is drawn between them.
>As it ruptures, it may
>leave more metal on one contact than on the other. This is called bridge
>transfer and opinions
>differ as to exactly how it occurs. A short arc is drawn as the bridge
>breaks. Electrons emitted
>from the negative terminal (cathode) cross the gap without interference
>(the gap at this time is
>too short to contain many gas atoms) and bombard the positive terminal
>(anode). Their high
>energy causes ionization of some of the surface atoms of the anode
>terminal. The resulting
>positive ions of negative contact material are repelled by the anode and
>attracted to the cathode.
>
>Thus, metal is moved from anode to cathode. As the contacts continue to
>separate, a phenomenon
>occurs which moves material in the opposite direction in the form of vapor
>and continues until
>the contacts are about 4 microns apart (assuming silver contacts in air).
>
>As the contacts continue to separate, a significant amount of electron
>avalanching begins and a
>plasma of ionized gas develops. The gap becomes wide enough to contain an
>appreciable amount
>of ambient gas. Electrons emitted by the cathode strike gas atoms, losing
>some of their energy in
>the process, ionizing some of the gas atoms and thus releasing more
>electrons. The electrons
>reaching the anode have such low energy that ionization of the anode
>practically stops. Pressure
>of the metal vapor in front of the cathode is higher than that in front of
>the anode, and the
>pressure differential draws a jet of metal vapor from the cathode. The jet
>strikes the anode and
>the vapor condenses there. This is called plasma arc transfer and causes
>migration of metal from
>cathode to anode.
>
> Wow! Things are starting to happen at 4 microinches of separation.
> If your interested in having these documents they can be
> acquired from the reference docs page on my website at:
>
>http://aeroelectric.com/Reference_Docs
>
> Go to the Microswitch folder and download the two .pdf files.
>
> The most striking feature of the article is lack of depth with
> respect to contact life issues. For example.
>
> Here's a 5A relay that has been qual tested to over 100,000 cycles
> at full load.
>
>http://www.aeroelectric.com/Pictures/MaintRelay_D.jpg
>
>
> Looks pretty bad . . . but it STILL met requirements for normal
> operations.
>
> Now look at this relay:
>
>http://www.aeroelectric.com/Pictures/1_B30K3_stick.jpg
>
> This relay was sticking at less than 30,000 cycles and was
> a player in a trim runaway scenario. Part of what drove the
> sticking phenomenon was contact bounce and downstream
> conditions in the system which was documented here:
>
>http://www.aeroelectric.com/Pictures/4_bounce500Knocap1.gif
>
> EVERY time the high failure rate relay closes, it takes
> 4-8 hits. Another brand of relay qualified to the same
> spec only bounces 2-3 times and had less than 1/10th the
> failure rate. This has nothing to do with presence
> or lack of arc suppression across the coil and little to
> to with textbook loading conditions.
>
> The article isn't "wrong" but it's very textbookish in
> and simply regurgitates a lot of standard stuff on contact life,
> most of which doesn't apply to light aircraft that fly an
> average of 50 hours a year. When I encounter relay and switch
> problems on airplanes, these are generally machines that fly
> hundreds of hours per year . . . and the root cause is almost
> never based on poor switch selection or failure to observe
> ratings.
>
> I'd advise caution before one reacts to this article as
> a basis for making design decisions . . . I've not researched
> the article in detail but it has some serious holes in the
> facts and logic.
>
> Bob . . .
>
>
>
>
________________________________________________________________________________
| From: | "Matthew Brandes" <matthew(at)n523rv.com> |
| Subject: | Master/Starter Contactor connection |
Connected my starter and master contactor with a single piece of bus bar...
should I use two pieces?
Matthew Brandes,
Van's RV-9A (Finish Kit)
#90569
<http://www.n523rv.com/> http://www.n523rv.com
EAA Chapter 1329 President
EAA Chapter 868 Web Editor
________________________________________________________________________________
| Subject: | Re: Contact Arc Suppression |
Hi Bob and all,
> The territory just above 16v isn't the edge of the earth . . .
>
>
This discussion is most interesting. But why should 16 V be deemed too
high, while airplanes and helicopters have been running on 28 V DC for
more than half a century ?
Voltages in the 12/16 V range are not that high after all.
Or am I missing something ?
Regards,
Gilles Thesee
Grenoble, France
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Contact Arc Suppression |
><Gilles.Thesee@ac-grenoble.fr>
>
>Hi Bob and all,
>
> > The territory just above 16v isn't the edge of the earth . . .
> >
> >
>This discussion is most interesting. But why should 16 V be deemed too
>high, while airplanes and helicopters have been running on 28 V DC for
>more than half a century ?
>Voltages in the 12/16 V range are not that high after all.
>Or am I missing something ?
Excellent question . . . and I think the authors stubbed
their toe on that on. The notion that something evil happens
in that range is not supported by others. I didn't do an
extensive literature search but I was unable to find a
single reference to the relatively high striking voltage
for arcs in opening contacts. The Microswitch papers
clearly argued with their premise.
Higher voltage DC systems have been around longer than
6v or even 12v cars. Large boats got electrical systems
before cars did . . . and they recognized the value of higher voltage
devices (mostly lighting and ventilation fans) being
wired with smaller wire if the current could be kept low.
32V wasn't 'easy' to control but they managed. Railroads
had 32v lighting systems driven from the same class of
generators used for wind-charging of batteries in rural
households. The generators are visible on the running gear
of antique passenger cars of the early 1900s. Each car
had its own generator/battery combination.
32 volt lamps are still made to support marine applications.
My dad served on a wooden hulled mine sweeper in the "1000-mile
War" in Alaskan waters. It had a 32v system . . . twisted pair
to reduce generation of stray magnetic fields.
http://www.atlantalightbulbs.com/ecart/nw012104/6S6.30V.htm
http://www.go2marine.com/g2m/action/GoBPage/id/16170F/medium_screw_standard_base_lamp_bulbs_ancor.html
Chas. Kettering's first starter was a 24 volt machine.
But for some reason, 6V generators were the hardware
of choice. This means that he had to charge 4 batteries
in parallel and discharge them into the 24 volt motor
with an elaborate switching arrangement. It would be
interesting to see the "starter control" on this vehicle.
I imagine a rather large lever with considerable throw . . .
but still preferable to the arm wrenching crank. See
"1911 Application for car self-starter patent" at:
http://www.safran-arts.com/42day/history/h4apr/h4apr17.html
The folks anticipating higher voltage cars are having
to re-invent the wheel. Higher voltage DC equipment for
the railroad/marine markets is fairly hefty and largely
tolerant of the special needs for switchgear. Now they
need to miniaturize it. I suspect we'll see a LOT more
solid state switching just to get rid of the classic
moving contact switches and relays.
But the 12 volt breakover voltage doesn't make sense.
Just for grins, I just went the bench and loaded a 1.2
volt NiMh battery with a 1 ohm resistor (1.2 amp current
draw). Looking at the "contact" area under a microscope
in a darkened room, both a closing and opening arc
were clearly visible. If the 12 volt breakover threshold
were operating, I shouldn't have been able to see
anything.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Contact Arc Suppression |
>
>Hmmm. Back when I was blowing up power transistors for a living :-) , I
>had to quickly learn about SOA (Safe Operating Area) of semiconductor
>devices.
>Switching off any load, especially inductive loads, can overstress
>electronic devices unless explicit steps are taken to prevent it. It
>appears that the exact analogy exists for mechanical contacts. A
>particular contact (switch, relay, contactor) will have a manufacturer's
>specified SOA... a combination of dynamic voltage and current conditions.
>
>The 'fix' I used for transistors was called a snubber circuit: a
>resistor and capacitor in series connected from the collector to
>emitter. In a switching power supply, this get's very warm so component
>selection was important. In an aircraft, a snubber circuit would only
>have to handle instantaneous power, but the average power would be very
>low.
>
>The Polyswitches are fancy snubbers, and my opinion is that they are not
>foolproof.
>
>My question to Bob is: do you have any experience with prevention of
>contact welding by using R-C snubbers?
Absolutely. See Figure 6-2 in the 'Connection. R-C arc suppression
was the technology of choice in the design and fabrication of
OV RELAYS in 1975. Problem was that the capacitor, resistor and
contact spreading characteristics were tuned to the inductive
characteristics of the alternator for best life. Fortunately,
one life-time then was 50 cycles as far as Beech and Cessna
were concerned.
The OV relay I was replacing was this big hog:
http://www.aeroelectric.com/Pictures/RBM138-1_B.jpg
The boss said a design goal was to make it 1/10th the weight
an volume. This is the same kind of challenge the 42 volt
car guys are facing. 32v equipment for boats and railroads
was honky stuff with enough size and mass to shrug off
arcing. Now, the task is to handle the same switching
job in a miniature, hermetically sealed relay that is
indeed small . . . but vulnerable to arcing.
So a new paradigm was born with R-C snubbers that the
original product got along without. The paradigm shifted
again when the crowbar system came along with a design
goal to force all contact closure into solid state device
(SCR) for no contact bounce. Contact opening was
moved to a circuit breaker being asked to handle exactly
the task it was designed for: clear a resistive hard fault.
All the issues driven by the inductive nature of
alternator fields simply evaporated.
From the energy management perspective, it was a marriage
made in heaven. For the first time, meeting the service
life requirement of 50 consecutive faults was easy . . .
the new system would readily handle hundreds if not thousands
of repeated OV events.
Bob . . .
>Vern Little RV-9A
>
>Robert L. Nuckolls, III wrote:
>
>
> >
> >
> >
> >
>
> >>
> >>The automotive industry has been moving gung-ho towards 42 volt
> systems. The
> >>gung-ho slowed considerably when it was generally appreciated that
> there was
> >>no way to make a contact arc extinguish reliably. This could lead to
> >>horrendous consequences where switches or relays were opened and the
> current
> >>just continued in a bright arc until something melted into a puddle. The
> >>progress towards 42 volt is now more tentative.
> >>
> >>
> >
> > Hadn't heard about this "stumbling block" . . . I just assumed that
> > part of the 42v development goals would be to eliminate mechanical
> > switches . . . solid state devices don't arc (they've got other
> > vulnerabilities to the same stresses however).
> >
> >
> >
> >
> >>A standard B+ contactor for disconnecting the alternator in the case of an
> >>alternator runaway may not work if the contactor is suddenly presented with
> >>a voltage much above 13-16 VDC, because the arc may not extinguish.
> >>
> >>
> >
> > The territory just above 16v isn't the edge of the earth . . . the
> > dielectric strength of air is about 1000v/mil . . . but how far apart
> > are contacts of a switch when they first open? Micro-inches,
> nano-inches,
> > pico-inches? How much voltage does it take to jump damned few inches?
> > Damned few volts. So every set of contacts that open under any
> >circumstances
> > for current flow and system voltage WILL arc.
> >
> > Contact mass, spreading velocity, arc source rise time and ultimate
> limits
> > to open circuit amplitude in both voltage and energy are key players and
> > tightly interlinked.
> >
> > One can mitigate an arcing situation with any combination of adjustments
> > to these effects. For the past few months, transorbs have been under
> >discussion
> > as means by which ultimate voltage and total energy available to feed
> >an arc
> > can be brought to heel. Contactors and switches can be selected or
> modified
> > to improve on resistance to arcing under conditions presented by the
> >system.
> >
> > Of particular interest to me right now is the capability of a
> >Stancore/White-Rogers/
> > RBM Controls generic contactor to disconnect an internally regulated
> >alternator
> > after it's well into the self destructive cycle of a regulator failure.
> >Here
> > we know that transorbs won't help . . . they're for transient,
> >relatively low
> > energy events. The runaway alternator is not transient. It goes on
> >until something
> > shuts it down (difficult from the outside on an internally regulated
> >alternator),
> > or it destroys itself. The best we can hope for with incorporation of a
> >b-lead
> > contactor is that we can effectively disconnect it from the rest of the
> >airplane.
> >
> > Here, the event isn't "just above 16" or even 32 volts (general
> rating for
> > contacts in this product) but well over 100 volts.
> >
> >
> >
> >
> >>Arcing of contacts is typical of DC systems with voltages much higher than
> >>standard automotive voltages.
> >>
> >>
> >
> > I'd caution the use of "standard" in this context. Boats, railroads,
> > wind driven generators on farms have used 18-cell (36v battery/42 volt)
> > systems for nearly 80 years and they all had to learn to live with
> > the task of making and breaking circuits.
> >
> >
> >
> >>A huge amount of engineering has gone into
> >>making contacts survive. Many engineers have spent their entire career on
> >>the subject.
> >>
> >>
> >
> > Absolutely! The volumes of data available on contact science is
> > staggering. Just consider this alternator regulator from Ford
> > circa 1960.
> >
> >http://www.aeroelectric.com/Pictures/Ford_EM_Reg.jpg
> >http://www.aeroelectric.com/Pictures/Ford_EM_Reg_Volage_Relay.jpg
> >http://www.aeroelectric.com/Pictures/Ford_EM_Reg_Field_Relay.jpg
> >
> > Here's a set of contacts that had to switch the most inductive
> > load in a vehicle (alternator field) hundreds of times per
> > second for thousands of miles of operation of the vehicle.
> > No transorbs were available at the time. However, both regulation
> > dynamics and contact life were enhanced by putting some constant
> > ON bias to the alternator field with a resistor visible here:
> >
> >http://www.aeroelectric.com/Pictures/ALTREG6.JPG
> >
> > While this helped, designers still had to depend on VERY hard
> > contact material common to distributor points and copper-n-steel
> > regulators that dated back to the 1920s.
> >
> >
> >
> >> A couple years ago Tyco engineers looked at the problem and
> >>someone decided that this was a perfect application for their Polyswitch.
> >>
> >>The Tyco refs are:
> >>http://www.circuitprotection.com/appnotes/AppNote_42V_PR.pdf
> >>
> >>Remarkably, if you choose the right polyswitch there is NO CONTACT ARC AT
> >>ALL.
> >>
> >>
> >
> > Interesting application for this device. Pretty slick.
> >
> >
> >
> >
> >>To explain how this can be
> >>http://www.periheliondesign.com/downloads/Polyswitch.pdf --imagine a
> >>Polyswitch across the contacts, in parallel with the contact gap. I have
> >>used a relay to illustrate this, but it works the same in switches and
> >>connectors. Everything is OFF. The Polyswitch in its OFF condition has a
> >>very low resistance, thus for an instant the Polyswitch actually conducts
> >>before going into its high resistance mode. (This is not optimal in all
> >>circumstances but we can examine it later).
> >>
> >>When the relay is energized, the contacts close. As a general rule, this
> >>does not cause arcing below 330 volts or so. The Polyswitch is now shorted
> >>or bypassed by the path through the relay contacts. As a consequence, the
> >>Polyswitch goes cold and reverts to its Low Resistance state.
> >>
> >>
> >
> > Hmmm . . . I've worked dozens of contact life issues on the airplanes'
> > over the years and virtually ALL of them had issues based on contact
> > closure (bounce) and downstream loads (lamp loads, reactive loads due
> > to combined effects of shielded wire and radio filter capacitors, etc).
> > None had issues with respect to arcing on contact opening.
> >
> >
> >
> >
> >>When the relay is turned off, the Polyswitch is still shorted across the
> >>contact gap, and as a result, prevents any contact arcing. In an
> instant the
> >>Polyswitch heats up and goes into its high resistance state--thus turning
> >>off the circuit.
> >>
> >>There will be more on this as time allows, but the key point here is that
> >>the B+ contactor should probably be equipped with such a scheme to ensure
> >>that the B+ line is really cut off. Contactors, relays, connectors, and
> >>switches will last about forever with such a scheme.
> >>
> >>
> >
> > Don't know about forever but it will indeed be a quantum jump in
> > service life.
> >
> >
> >
> >
> >>Caveat: Nobody said it was easy. Some selection of the proper part is
> >>required. Perhaps some experimenting needs doing.
> >>
> >>If you are not convinced that this is a good idea I suggest some reading
> >>about the micro-details of how contacts open. Terrifying reading!
> >>http://relays.tycoelectronics.com/app_pdfs/13c3203.pdf
> >>
> >>Finally please note the bi-directional transorbs across the coils.
> >>
> >>
> >
> > I read this article. It's generally factual but contains
> > a lot of non-quantified conditions. Further, it's got some
> > fundamental problems with their description of contact physics.
> > For example, the authors allude to a 'breakover voltage' depending
> > on contact material to wit:
> >
> >
> >Different contact materials have different arc voltage ratings. For fine
> >silver, the arc voltage is 12 volts. For cadmium, it is 10 volts; and
> for gold
> >and palladium it is 15 volts. Let's assume the contacts are fine silver.
> >Within nanoseconds after the molten bridge explodes, if the material is
> >silver and if circuit voltage is 12 volts or more, voltage breakover occurs.
> >If circuit voltage is less than 12 volts, breakover cannot occur and there
> >will be no arc.
> >
> > Hmmmm . . . . the dielectric strength of air is about 1000v/mil.
> > What is the gap between contacts when they FIRST open? Nano
> > inches? Picoinches? Damned small inches. This suggests the
> > the potential for establishing an arc across spreading
> > contacts with damned small volts as well. Quoting from some
> > Honeywell-Microswitch documents on contact and switch physics . . .
> >
> >
> >During contact bounce on closure, molten metal splashes. As the contacts
> >separate to open the
> >circuit, arcing occurs again. Meanwhile, things are happening on the atomic
> >scale. As the
> >contacts begin to separate, a bridge of molten metal is drawn between them.
> >As it ruptures, it may
> >leave more metal on one contact than on the other. This is called bridge
> >transfer and opinions
> >differ as to exactly how it occurs. A short arc is drawn as the bridge
> >breaks. Electrons emitted
> >from the negative terminal (cathode) cross the gap without interference
> >(the gap at this time is
> >too short to contain many gas atoms) and bombard the positive terminal
> >(anode). Their high
> >energy causes ionization of some of the surface atoms of the anode
> >terminal. The resulting
> >positive ions of negative contact material are repelled by the anode and
> >attracted to the cathode.
> >
> >Thus, metal is moved from anode to cathode. As the contacts continue to
> >separate, a phenomenon
> >occurs which moves material in the opposite direction in the form of vapor
> >and continues until
> >the contacts are about 4 microns apart (assuming silver contacts in air).
> >
> >As the contacts continue to separate, a significant amount of electron
> >avalanching begins and a
> >plasma of ionized gas develops. The gap becomes wide enough to contain an
> >appreciable amount
> >of ambient gas. Electrons emitted by the cathode strike gas atoms, losing
> >some of their energy in
> >the process, ionizing some of the gas atoms and thus releasing more
> >electrons. The electrons
> >reaching the anode have such low energy that ionization of the anode
> >practically stops. Pressure
> >of the metal vapor in front of the cathode is higher than that in front of
> >the anode, and the
> >pressure differential draws a jet of metal vapor from the cathode. The jet
> >strikes the anode and
> >the vapor condenses there. This is called plasma arc transfer and causes
> >migration of metal from
> >cathode to anode.
> >
> > Wow! Things are starting to happen at 4 microinches of separation.
> > If your interested in having these documents they can be
> > acquired from the reference docs page on my website at:
> >
> >http://aeroelectric.com/Reference_Docs
> >
> > Go to the Microswitch folder and download the two .pdf files.
> >
> > The most striking feature of the article is lack of depth with
> > respect to contact life issues. For example.
> >
> > Here's a 5A relay that has been qual tested to over 100,000 cycles
> > at full load.
> >
> >http://www.aeroelectric.com/Pictures/MaintRelay_D.jpg
> >
> >
> > Looks pretty bad . . . but it STILL met requirements for normal
> > operations.
> >
> > Now look at this relay:
> >
> >http://www.aeroelectric.com/Pictures/1_B30K3_stick.jpg
> >
> > This relay was sticking at less than 30,000 cycles and was
> > a player in a trim runaway scenario. Part of what drove the
> > sticking phenomenon was contact bounce and downstream
> > conditions in the system which was documented here:
> >
> >http://www.aeroelectric.com/Pictures/4_bounce500Knocap1.gif
> >
> > EVERY time the high failure rate relay closes, it takes
> > 4-8 hits. Another brand of relay qualified to the same
> > spec only bounces 2-3 times and had less than 1/10th the
> > failure rate. This has nothing to do with presence
> > or lack of arc suppression across the coil and little to
> > to with textbook loading conditions.
> >
> > The article isn't "wrong" but it's very textbookish in
> > and simply regurgitates a lot of standard stuff on contact life,
> > most of which doesn't apply to light aircraft that fly an
> > average of 50 hours a year. When I encounter relay and switch
> > problems on airplanes, these are generally machines that fly
> > hundreds of hours per year . . . and the root cause is almost
> > never based on poor switch selection or failure to observe
> > ratings.
> >
> > I'd advise caution before one reacts to this article as
> > a basis for making design decisions . . . I've not researched
> > the article in detail but it has some serious holes in the
> > facts and logic.
> >
> > 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
________________________________________________________________________________
authenticated user rwtalbot);,
28 Apr 2005 09:31:18+1000(at)roxy.matronics.com (EST)
| Subject: | SD-8 and No Battery |
Just to clear up my mind.... Will the SD-8 installed as per Bob's
recommendations function acceptably in the event that it is disconnected
from the battery?
Is the battery needed to get the SD-8 "started"?
Richard
________________________________________________________________________________
| Subject: | Re: Contact Arc Suppression |
BobsV35B(at)aol.com a crit :
>
>
>Good Afternoon Bob,
>
>For What It Is Worth!
>
>The Caravelle Sud Est 210
>
Hi Bob S,
Funny you mention the Caravelle. I believed it was essentially to be
found in Europe and Mediterranean countries. Or did you have some in the
USA ?
I may have some schematics in the attic.
Regards,
Gilles Thesee
Grenoble, France
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Master/Starter Contactor connection |
>
>
>Connected my starter and master contactor with a single piece of bus bar...
>should I use two pieces?
Don't know why you would need to. What are your concerns?
We often "bus" multiple devices that would normally accept
terminals for fat-wires.
If I understand your question, the pictures below
are illustrative of copper (or brass) straps used
to connect adjacent terminals of high current
carrying devices.
http://www.aeroelectric.com/Pictures/DISKA09F.JPG
http://www.aeroelectric.com/Pictures/DISKA11F.JPG
http://www.aeroelectric.com/Pictures/DISKA12F.JPG
Bob . . .
________________________________________________________________________________
| From: | Charlie Kuss <chaztuna(at)adelphia.net> |
| Subject: | Re: Rebuilt versus Original |
At 06:36 PM 4/26/2005, you wrote:
>
>There has been some disparagement of rebuilt equipment recently--so I think
>we should set the record straight.
>
>Is original stuff better than rebuilt?
>
>Original equipment is "good enough" for the task, and task is mainly to
>satisfy the customer until the warranty expires. I'm not being cynical here.
>Since the huge production volumes are sensitive to costs, nothing that is
>better than what-is-needed-to-satisfy-the-task is required. In fact to do
>anything else would be throwing money away. My Dad showed me how American
>machine tools made in 1941 would have the sharp edges INSIDE castings
>smoothed down while the same machine made a few months later would not. The
>task had changed.
>
>It is also true in some assembly operations that a part which goes into an
>assembly may have inspections and tests done on it which a part destined for
>the new original stock (but not used in an assembly) never has to undergo. A
>part that comes out of a box may indeed be inferior to a part out of a
>junkyard in these instances. Selling slightly not-so-good parts in the
>aftermarket is common.
>
>But let's look at original and rebuilt alternators.
>
>Mythical rebuilding operation: Starting with a "core", the alternator is
>disassembled. All the fasteners and bearings are thrown away and new ones
>are used. The bearings can be of better quality than original. The case,
>rotor and stator are inspected and cleaned up. Often new, higher
>voltage-withstand diodes are retrofitted, new brushes are added. Often a new
>regulator assembly (incorporating the newest electronics) is fitted.
>Everything is inspected, torqued, fitted, and sometimes, YES (per B&C,
>thanks Bill...) even dynamically balanced.
>
>Is this better than new? Probably so....In many cases it certainly is. Offer
>to take the rebuild shop owner up in your airplane. Watch his reaction.
>
>Regards,
>Eric M. Jones
Eric,
What you say may be true in some instances. My experience as a
professional auto mechanic, is "you get what you pay for". Cheapo
remanufactures "usually" have poor quality rectifier diodes, bearings and
voltage regulators. If you want a good unit, you usually have to pay for
it. Ask the vendor whose parts (brand) do you use in your units. If they
don't know, generally, the parts are "crap".
Charlie Kuss
________________________________________________________________________________
| From: | <gmcjetpilot(at)yahoo.com> |
| Subject: | Re: Internally regulated alternator OVP protection |
Thanks Larry and Doug:
Larry and Doug pointed out to me off list, I should not respond to personal
comments. I totally agree. I made a mistake and apologize to all if I offended.
Thanks Larry and Doug. Regards George.
Some want to know some background. It is free advice and worth every
penny. If you really care write me off line. The short story is I am a former
aerospace engineer for Boeing and consultant, now fly for a living. I have a
CFI-(I)-MEI, ATP 737/57/67,CE500. My degree is ME engineering and
went to grad school at UW. I was not smart enough to be an EE but they force
dumb ME students to take some EE courses anyway. Also I am an amateur
electronic hobbyist (since age 10 with my radio shack science-fair 160 in 1
electronics project kit) and now work with complex aircraft electrical systems.
Im now building a RV-7 and have had my hand building a RV-6 and finishing a
RV-4, which I flew for many years until selling it. I am concerned not paranoid
about internet fraud and privacy of info. No apologize, just the way it is. If
you
want to pick my brain off list great, but pretty slim pick-ins. Regards George
============================================
>"Chris & Kellie Hand" Subject:
>Re: Internally regulated alternator OVP protection Date: Apr 26, 2005
>
>Ken & Bob,
>Thanks for the education...and at the risk of sound a little EE-ignorant, I
>hope you don't mind a few follow up questions:
>
>When you say you've replaced a few similar shorted transistors, are you
>talking about replacing ICs due to short type faults (how could you tell?),
>or are you talking about a failed stand-alone single transistor in a ckt?
Good question Chris
============================================
>From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> protection Subject:
>Re: Internally regulated alternator OVP protection protection
>
>Hi Chris
>
>>"If the field driver shorts (part MTB20N20E in your first reference or
>>part 2N6284 in your second reference) then there is no way that I can
>>see for the referenced devices to stop an over voltage. How likely is
>>that - I don't know but I have replaced a few similar 'transistors' that
>>were indeed shorted in other equipment over the years.
>
>Hear hear! This is exactly the simple-idea upon which
>the notion of additional OV protection and/or external
>control by means of switch on panel is based. Every alternator
>has some sort of solid state device in series with the field
>with a responsibility to modulate field current in response
>to regulator commands for voltage control. If that puppy
>fails shorted -OR- gets an uncontrolled ON-command from
>failed circuitry elsewhere, the alternator's voltage is
>officially out of the gate and racing for the moon.
>
Gents that went over the head of 99% of the audience, including me.
What I got from this is "If driver shorts", "how likely, I don't know", "I replaced
transistors....shorted...in other (?) equip..."
That is all good, but.what kind of short? What equip? what kind of transistor are
we talking about?
We are talking about a catastrophic transistor failure. Right? Also it must fail
in a
very specific way. The transistor drives how much current flows to the field. The
IC controls this transistor. The more current to the field, the higher the alternators
output. So far so good. Normally the IC senses voltage and if there is over voltage
it tells the drive transistor to shut down, but in this scenario the transistor
fails in
such a way the IC is not in control of it. In this scenario there is no fuse/current
limiting device also in the picture in the event this happens.
The IC is watching the transistor and sensing currents thru out the alternator.
The
logic should detect an impending transistor melt down (short). Do transistors just
melt down to a dead short between the drain and source? I have not plowed thru
the whole 20 page document yet but page one has a good diagram and page 14,
par: Field Coil Drive Device Protection, Drive Device = transistor.
http://www.freescale.com/files/analog/doc/data_sheet/MC33099.pdf
The proposed scenarios is a catastrophic instantaneous failure of the transistor
resulting in a loop where the alternator drives it self right up to the rails.
The
transistor (FET) must not only fail it must fail in a mode where the (drain) and
(source) short. Transistor control (gate) provided by the IC is not effective.
We
have a real melt down. Also we are going to assume there is no other internal
current limiting or fuse backup in the loop to protect from this runaway loop,
if
the transistor melts-down in this very specific way. The ND diagram I have does
show a fuse or current limiter in the loop. How it exactly works I cant tell you?
The IC normally will shut the current off to the transistor (gate) if it senses
a
pending overload or shorted output transistor by comparing the response of the
transistor to control input. In the above failure the IC short/overload protection
control of the transistors has no affect, full melt down is already in effect.
This
sudden catastrophic melt down might be very rare. I am thinking a common
failure would be just an open failure, not a short. Also many transistors short
to
the (gate), meaning it will stop current from running thru it (drain to source).
So what is Bob and Chris saying? What I get out of it is a rare transistor
failure will fail dead short, not open. The IC's controls the alternator (field),
thru
that transistor will not catch it in time and all control lost. That is a lot
of bad things
to one component, but possible? Dont know. I am not saying can't happen, just
that it sounds unlikely with the reliability of transistors and the smarts of IC
protection are pretty good.
(WARNING: EE types dont read the following, your head will explode. )
I think some basics are in order. I promise its not too technical, because I dont
know that much.
Transistors are real reliable. The kind in the new alternators, field effect
transistors, (FET or MOSFET), are very reliable. Also the way the VR controls the
FET produces much less heat than older designs. What the industry says about
these transistors is what you already know from the reliability of your TV, they
rarely fail in short. The topic of how transistors fail is a subject for a PHD.
The
field-effect transistor is a very important type of transistor developed after
the
junction transistor. It draws virtually no power from an input signal, overcoming
a
major disadvantage of the junction transistor. You have much less heat with a FET
than older designs using junction transistors. They are faster acting which allows
them to be controlled with pulse width modulation, PWM. This means the controlling
current is turned on/off very fast, and the width of the pulses is varied to control
the transistors output. Way more efficient and cooler.
Keeping the transistor cool is important; that is why they have heat sinks attached.
Even though the FET runs real cool, a heat sink gets rid of heat and adds reliability.
(Look at a ND alternator, you will see the cooling fins. Not all internal VR have
this.)
=================================================
>>If a separate external OVP device fails to work when it should then we
>>have two separate devices failing simultaneously which is pretty rare.
>>We can't test the functionality of an OVP internal to an alternator but
>>we can test the separate OVP device if we so desire.
>
>Dead-on . . .
Agree, multi failures are rare, and that applies to internal regulators also. The
trans melt I understand and I guess you could have a IC failure but still think
this is in the rare range. The IC has its own fault protection, in other words
the
"chip" in the chip is watching the shop. The specific transistor failure that the
IC voltage regulator cant control or "predict" is also got to be rare. What about
the secondary fuse in some internal VR alternators.
CERTIFICATION ANYONE?
A company called Plane-Power in Texas is in the process of certifying PMA
replacement alternators based on Nippondenso alternators. They will offer internal
and external voltage regulated versions. The certified versions will replace existing
systems with external regulators, therefore they will also do the same. For the
experimental market, in the next 2 months, they will have kits for $400, with
brackets, both internal and external regulated. If you buy the external regulated
model it will not come with a regulator. What about the internal VR version. As
I
understood it from Steve at plane-power said they modify the stock VR and add an
internal crow-bar on the condition wire. I confirmed the condition wire was
not a field wire and was the IGN wire (also known as: sense wire or on/off
wire). I know that this approach is not advocated by Bob N. If that is a good
approach than we could we just add the OV crow-bar on the breaker of an internal
regulated alternator just like an external regulator? It would not help if your
field
driver transistor was dead short, as described above? However I am sticking to
my guns, and will not be adding any extra OV protection to my ND alternator at
this time. Yea for me.
=================================================
>>FWIW my feeling is that yes external OV protection is a good thing on an
>>IR alternator but not essential for most of us. I suspect that it will
>>indeed decrease overall system reliability and I doubt very much whether
>>that is going to be quantified on this forum. However I also believe it
>>reduces risk to my brand new icomm A-200 transceiver that still warns
>>that over 16 volts will kill it and that it must be turned off during
>>engine starting... (%$#%) I did add the transorbs to the alternator
>>side of the my ov contactor to increase the likelihood of the contactor
>>working as desired. And I'm still happy with my decision to not route
>>the alternator B-lead through a battery master.
>
>Which goes to another post of mine that speaks to design goals. There
>are no REQUIREMENTS that any of us can levy upon the wishes
>and goals of any other builder. Lots of folk are tightly
>wrapped around an axle assuming that what I write has
>come manner of social design goal to control or set requirements
>on other people's actions.
>Ken is demonstrating a high level of understanding that
>would assuage any concerns I might have should I have
>an opportunity to ride with him in his airplane.
>
>This kind of conversation is what makes the AeroElectric-List
>an arena of ideas as opposed to a barroom brawl over who
>is trying to control whom.
>
>Bob . . .
The fastest way to turn off an over voltage exist inside a modern alternator. Not
with standing the melted shorted transistor scenario above, the internal OV
protection will react very fast. So fast the buss may never see the OV. The crow
bar method does have to wait for the buss to see the OV first (along with radios)
and than wait to pop the CB, which may take a fraction of a second. How much
abuse your radio can take.
The auto industry cant stand over voltage or transient voltage any better than
your
avionics, may be even less (air bag, engine, transmission, anti-lock computers,
gps,
stereos). Bob N. says we need not bother with a master switch and turning off
radios for start, which I understand. This is because modern radios have their
own
protection, but I have a master switch I am ashamed to say. Sorry Bob. It makes
me
feel better. Unless you really know how resilient your avionics are (like the icom
A200, which I have) its prudent to take precautions as you see fit, as Bob says.
The
same with OV protection on top of internal regulated alternators. If you feel you
must add the OV protection, do it. Chances are it will never be needed, you hope.
Worst case scenario is it accidentally trips and causes your alternator some grief,
but your radios should be safe.
Bottom line you have to have a transistor fail. It must not only fail, but fail
in a
specific way. In this mode how much current can flow thru it with out just opening
and basically acting as a fuse? Is the IC capable of proactively preventing it
failing
in the first place, thru good control and logic? What about other internal fuses?
Cheers George
________________________________________________________________________________
| From: | Charlie Kuss <chaztuna(at)adelphia.net> connection |
| Subject: | Re: Bus bars was Master/Starter Contactor |
connection
At 08:38 PM 4/27/2005, you wrote:
>
>
>
> >
> >
> >Connected my starter and master contactor with a single piece of bus bar...
> >should I use two pieces?
>
> Don't know why you would need to. What are your concerns?
> We often "bus" multiple devices that would normally accept
> terminals for fat-wires.
>
> If I understand your question, the pictures below
> are illustrative of copper (or brass) straps used
> to connect adjacent terminals of high current
> carrying devices.
>
>http://www.aeroelectric.com/Pictures/DISKA09F.JPG
>http://www.aeroelectric.com/Pictures/DISKA11F.JPG
>http://www.aeroelectric.com/Pictures/DISKA12F.JPG
>
> Bob . . .
Bob,
I've made 3 short bus bars for the electrical system on my RV-8A. I have
access to a solder pot. Is it worth my time to "Tin" these bars prior to
installation?
Charlie Kuss
________________________________________________________________________________
| From: | "bob rundle" <bobrundle2(at)hotmail.com> |
| Subject: | Shunts and loadmeters |
I'm just starting to build a RV7AQB. I have IO-360 engine with B&C 60 Amp
Alt and 8A stby alt.
I'm following Z-12 drawing for the most part. I have a few beginner
questions:
1. Are the shunts usually located in the engine compartment? I notice the
wiring from the starter solenoid to the shunt should be 6 inches or less.
2. Is the sole purpose of a shunt to permt the hookup of an ammeter?
3. In Z-12 there is an indication of 2 ammeters (same as loadmeter) being
hooked up. Is the practice to just use 1 ammeter and a switch to go from
main alt to stby alt?
I'm also planning on 1 left side magneto and right side plamsa III ignition.
I'm planning on using a keyed switch to turn on the mag and start the
engine, plus a separate switch for the ignition. Does this sound like a good
combination?
Thanks very much as I get started understanding the electrical system
better.
BobR
________________________________________________________________________________
| From: | "Matthew Brandes" <matthew(at)n523rv.com> |
| Subject: | re: Master/Starter Contactor connection |
Bob,
My concern was doing it right. :-) This is a case of "he did it, maybe I
should too?".
Thanks, I'll leave it as it is. FWIW, here is a picture of it:
http://www.n523rv.com/finishing/Dsc01134.jpg
Matthew Brandes,
Van's RV-9A (Finish Kit)
#90569
<http://www.n523rv.com/> http://www.n523rv.com
EAA Chapter 1329 President
EAA Chapter 868 Web Editor
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> protection |
| Subject: | Re: Internally regulated alternator OVP |
protection
protection
>
>
>Gents that went over the head of 99% of the audience, including me.
>
>
>What I got from this is "If driver shorts", "how likely, I don't know", "I
>replaced
>transistors....shorted...in other (?) equip..."
>
>That is all good, but.what kind of short? What equip? what kind of
>transistor are
>we talking about?
A silicon junction transistor. It can be of any genre' PNP, NPN. Newer
designs will use MOSFET transistor, usually N-Fets for the lowest possible
on-resistance . . . but the clever designer can use P-Fets if he figures
an adequate way to get the heat out.
>We are talking about a catastrophic transistor failure. Right? Also it
>must fail in a
>very specific way. The transistor drives how much current flows to the
>field. The
>IC controls this transistor. The more current to the field, the higher the
>alternators
>output. So far so good.
Correct in a broad sense . . . specifically, modern regulator transistors
are used as switches, not valves. They are either ON or they are OFF. In
and ON state, current through the device may be high, but the voltage
is low, hence low watts. In the OFF state, current is zero while voltage
is high, also low watts. Linear control is emulated by controlling the
ON/OFF ratio at some frequency, 200-1000 Hz.
> Normally the IC senses voltage and if there is over voltage
>it tells the drive transistor to shut down, but in this scenario the
>transistor fails in
>such a way the IC is not in control of it. In this scenario there is no
>fuse/current
>limiting device also in the picture in the event this happens.
Correct.
>The IC is watching the transistor and sensing currents thru out the
>alternator. The
>logic should detect an impending transistor melt down (short). Do
>transistors just
>melt down to a dead short between the drain and source?
Yup, they do that or they get the gate punched through causing it
to loose control of the current flow through the device.
> I have not plowed thru
>the whole 20 page document yet but page one has a good diagram and page 14,
>par: Field Coil Drive Device Protection, Drive Device = transistor.
>
>http://www.freescale.com/files/analog/doc/data_sheet/MC33099.pdf
Correct. The data for this chip is very well presented which
is good for marketing the device.
>The proposed scenarios is a catastrophic instantaneous failure of the
>transistor
>resulting in a loop where the alternator drives it self right up to the
>rails. The
>transistor (FET) must not only fail it must fail in a mode where
>the (drain) and
>(source) short. Transistor control (gate) provided by the IC is not
>effective. We
>have a real melt down. Also we are going to assume there is no other internal
>current limiting or fuse backup in the loop to protect from this runaway
>loop, if
>the transistor melts-down in this very specific way. The ND diagram I have
>does
>show a fuse or current limiter in the loop. How it exactly works I cant
>tell you?
Yup, you got it.
>The IC normally will shut the current off to the transistor (gate) if it
>senses a
>pending overload or shorted output transistor by comparing the response of
>the
>transistor to control input.
Where in the narrative do we find a feature that "senses impending
overload"?
> In the above failure the IC short/overload protection
>control of the transistors has no affect, full melt down is already in
>effect. This
>sudden catastrophic melt down might be very rare. I am thinking a common
>failure would be just an open failure, not a short.
Most transistor failures are over temperature induced which drives
the core temperature well above the 175C limit (for most devices)
and it does indeed become a solid blob of short. If the transistor
were subject to extraordinary currents (hard fault due to shorts
in field winding . . . it MIGHT exceed the bond-wire limits on
the transistor and fail it open . . . but this is very rare compared
to incidences of fail shorted.
> Also many transistors short to
>the (gate), meaning it will stop current from running thru it (drain to
>source).
>So what is Bob and Chris saying? What I get out of it is a rare transistor
>failure will fail dead short, not open. The IC's controls the alternator
>(field), thru
>that transistor will not catch it in time and all control lost. That is a
>lot of bad things
>to one component, but possible?
I didn't see that the IC knows anything about impending failures
and yes, you have correctly deduced the failure mode being discussed.
> Dont know. I am not saying can't happen, just
>that it sounds unlikely with the reliability of transistors and the smarts
>of IC
>protection are pretty good
Don't think it has a thing to do with IC smarts.
>(WARNING: EE types dont read the following, your head will explode. )
>I think some basics are in order. I promise its not too technical, because
>I dont
>know that much.
>
>Transistors are real reliable. The kind in the new alternators, field effect
>transistors, (FET or MOSFET), are very reliable. Also the way the VR
>controls the
>FET produces much less heat than older designs. What the industry says about
>these transistors is what you already know from the reliability of your
>TV, they
>rarely fail in short. The topic of how transistors fail is a subject for a
>PHD. The
>field-effect transistor is a very important type of transistor developed
>after the
>junction transistor. It draws virtually no power from an input signal,
>overcoming a
>major disadvantage of the junction transistor. You have much less heat
>with a FET
>than older designs using junction transistors. They are faster acting
>which allows
>them to be controlled with pulse width modulation, PWM. This means the
>controlling
>current is turned on/off very fast, and the width of the pulses is varied
>to control
>The transistors output. Way more efficient and cooler.
>
>
>Keeping the transistor cool is important; that is why they have heat sinks
>attached.
>Even though the FET runs real cool, a heat sink gets rid of heat and adds
>reliability.
>(Look at a ND alternator, you will see the cooling fins. Not all internal
>VR have this.)
Your not wrong my friend . . . but you're talking about the ideal world
where
every user of this technology has the skill, integrity and marketing goals
to maximize the POTENTIAL you've identified for reliable operation.
>=================================================
>
> >>If a separate external OVP device fails to work when it should then we
> >>have two separate devices failing simultaneously which is pretty rare.
> >>We can't test the functionality of an OVP internal to an alternator but
> >>we can test the separate OVP device if we so desire.
> >
>
> >Dead-on . . .
>
>
>Agree, multi failures are rare, and that applies to internal regulators
>also. The
>trans melt I understand and I guess you could have a IC failure but still
>think
>this is in the rare range. The IC has its own fault protection, in other
>words the
>"chip" in the chip is watching the shop. The specific transistor failure
>that the
>IC voltage regulator cant control or "predict" is also got to be rare.
>What about
>the secondary fuse in some internal VR alternators.
I have seen this one time . . . in an old Mitsubishi design I think.
They incorporated the fuse/zener ov protection similar to that found
in some early American Aviation/Grumman products. A secondary, independent
way to overcome loss of the pass transistor. Neat idea. If EVERYONE used
this form of OV PROTECTION in their products, it would be a very good
thing for airplane builders. But alas, I don't believe it is common, in
fact I'm sure it's not common an perhaps non-existent in current production
>CERTIFICATION ANYONE?
>
>A company called Plane-Power in Texas is in the process of certifying PMA
>replacement alternators based on Nippondenso alternators. They will offer
>internal
>and external voltage regulated versions. The certified versions will
>replace existing
>systems with external regulators, therefore they will also do the same.
>For the
>experimental market, in the next 2 months, they will have kits for $400, with
>brackets, both internal and external regulated. If you buy the external
>regulated
>model it will not come with a regulator. What about the internal VR
>version. As I
>understood it from Steve at plane-power said they modify the stock VR and
>add an
>internal crow-bar on the condition wire. I confirmed the condition wire was
>not a field wire and was the IGN wire (also known as: sense wire or on/off
>wire). I know that this approach is not advocated by Bob N. If that is a good
>approach than we could we just add the OV crow-bar on the breaker of an
>internal
>regulated alternator just like an external regulator? It would not help
>if your field
>driver transistor was dead short, as described above? However I am
>sticking to
>my guns, and will not be adding any extra OV protection to my ND
>alternator at
>this time. Yea for me.
The supplier you've cited has recognized and accepted the task
of designing, investigating failure modes and doing the testing
to show minimum levels of reliability . . . usually numbers in
the 10 to the minus 6 or better failure rates. He is also
going to have to sign up for CONFIGURATION control that says every
product he sells is not compromised by any changes in design that
are not proven equal to or better than the original certification
basis.
>The fastest way to turn off an over voltage exist inside a modern
>alternator. Not
>with standing the melted shorted transistor scenario above, the internal OV
>protection will react very fast. So fast the buss may never see the OV.
>The crow
>bar method does have to wait for the buss to see the OV first (along with
>radios)
>and than wait to pop the CB, which may take a fraction of a second. How much
>abuse your radio can take.
>
>
>The auto industry cant stand over voltage or transient voltage any better
>than your
>avionics, may be even less (air bag, engine, transmission, anti-lock
>computers, gps,
>stereos). Bob N. says we need not bother with a master switch and turning off
>radios for start, which I understand. This is because modern radios have
>their own
>protection, but I have a master switch I am ashamed to say. Sorry Bob. It
>makes me
>feel better. Unless you really know how resilient your avionics are (like
>the icom
>A200, which I have) its prudent to take precautions as you see fit, as Bob
>says. The
>same with OV protection on top of internal regulated alternators. If you
>feel you
>must add the OV protection, do it. Chances are it will never be needed,
>you hope.
>Worst case scenario is it accidentally trips and causes your alternator
>some grief,
>but your radios should be safe.
>
>Bottom line you have to have a transistor fail. It must not only fail, but
>fail in a
>specific way. In this mode how much current can flow thru it with out just
>opening
>and basically acting as a fuse? Is the IC capable of proactively
>preventing it failing
>in the first place, thru good control and logic? What about other internal
>fuses?
If there were secondary, independent ov management, the guy doing this
certification task will find it MUCH easier to do. Secondary, independent
ov management does not exist in the design we've just reviewed.
So, in light of the discussion above, let's you and I play the role
of OBAM aircraft QUALIFICATION ADVISORS. What do we tell the OBAM
aviation community at large about the suitability of ANY automotive
alternator? Without a doubt, if the alternator can be shown to
have features and reliability studies suited for certification in
the spam-can world, then one can select that SPECIFIC product
for use in an OBAM aircraft with confidence. What would you advise
me as publisher of recommendations . . . what should my DESIGN GOAL
be for incorporation of automotive technologies into the OBAM
aircraft? I can take the position that only certifiable designs
should be used -OR- assume that none are certifiable (and presently
they are not) and comfortable integration suggests a means for
secondary, independent control of the OV condition . . . hopefully
without opening the as-received alternator for internal modifications.
You have correctly deduced the failure modes and illuminated an effort
on the part of one individual to overcome design shortfalls
and provide the aviation community with a product of known
quality. I'll suggest the real value of this discussion is to
cite what is NOT illuminated . . . we're no better informed as
to the suitability of an generic as-received alternator when
virtually none of the qualities we seek during certification
are known to us nor will they be made available.
This has been the frustrating part of the discussion. Those
who worship at the altars of any product claiming to offer modern
automotive reliability overlook the fact that ANYONE can start a church
based on any ideas . . . or none at all. While Plane-Power
seeks to be the true religion, we'll all expect and probably
receive a data dump of the simple-ideas that make their product
worthy of respect and acceptance. The little corner parts
stores or local junk yards will offer us a pew to occupy
and appreciate anything we'll throw in the plate when it's
passed . . . but ideas will not be forthcoming. The alternator
they sell you MIGHT be just as good as Plane=Power's . . .
but probably not. Without knowing the specifics, what
can I or anyone else offer in the way of considered advice?
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> connection |
| Subject: | Re: Bus bars was Master/Starter Contactor |
connection
connection
> connection
>
>At 08:38 PM 4/27/2005, you wrote:
> >
> >
> >
> > >
> > >
> > >Connected my starter and master contactor with a single piece of bus
> bar...
> > >should I use two pieces?
> >
> > Don't know why you would need to. What are your concerns?
> > We often "bus" multiple devices that would normally accept
> > terminals for fat-wires.
> >
> > If I understand your question, the pictures below
> > are illustrative of copper (or brass) straps used
> > to connect adjacent terminals of high current
> > carrying devices.
> >
> >http://www.aeroelectric.com/Pictures/DISKA09F.JPG
> >http://www.aeroelectric.com/Pictures/DISKA11F.JPG
> >http://www.aeroelectric.com/Pictures/DISKA12F.JPG
> >
> > Bob . . .
>
>Bob,
> I've made 3 short bus bars for the electrical system on my RV-8A. I have
>access to a solder pot. Is it worth my time to "Tin" these bars prior to
>installation?
Adding a third alloy in the joint MIGHT have some benefits
in terms of reducing electrolytic corrosion . . . but if
your joints are gas-tight, then dissimilar metals are not
a big issue. FLATNESS of interfacing surfaces and PRESSURE
are keys to longevity. Adding more "stuff" in the joint
only raises questions as to flatness. I'd clean 'em up
bright, bolt 'em tight and truck on . . .
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: re: Master/Starter Contactor connection |
>
>
>Bob,
>
>My concern was doing it right. :-) This is a case of "he did it, maybe I
>should too?".
>
>Thanks, I'll leave it as it is. FWIW, here is a picture of it:
>http://www.n523rv.com/finishing/Dsc01134.jpg
you done good
Bob . . .
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
4/28/2005
Hello Fellow Aero-Electricers, Yesterday I was involved in an event where
our two primary VHF communication radios in a C-172 failed** while airborne
and we could receive, but not transmit anything but carrier. This almost
stranded us outside the Washington DC ADIZ. Fortunately the airplane's owner
had a handheld Garmin GPS Comm with him and after a bit of fumbling we got
to enter the ADIZ and land at homefield.
The Garmin handheld was being powered by an adapter cable plugged into the
airplane's cigarette lighter socket. The NiCad battery for the handheld was
useless even though it had been charged the night before -- it is an old
battery and may not have been able to take and hold a charge.
I later realized that if we had had an electrical failure in the airplane
that would have removed our source of electrical power from the cigarette
lighter socket that we would have been without any means of communication.##
So what I am looking for is a battery case with the following
characteristics:
1) Small light weight plastic.
2) Holds enough AA batteries to put out about 12 volts for a relatively
short period of time at a relatively light load.
3) Includes a cigarette lighter receptacle that one could plug an adapter
cable into for powering 12 volt accessories like a hand held radio or GPS.
I thought that surely something like this must exist, but after an hour or
so on the internet last night I could not find such a critter. My request to
you is: Does such a thing exist and how can I get one?
Any other thoughts?
OC
**PS: I think the failure is due to over heating in the audio panel.
##PPS: I am aware in this circumstance that with no operating transponder we
would not be allowed into the Washington DC ADIZ, but that a different
story.
________________________________________________________________________________
| From: | BobsV35B(at)aol.com |
| Subject: | Re: Battery Help |
In a message dated 4/28/2005 1:04:38 P.M. Central Standard Time,
bakerocb(at)cox.net writes:
I thought that surely something like this must exist, but after an hour or
so on the internet last night I could not find such a critter. My request to
you is: Does such a thing exist and how can I get one?
Any other thoughts?
OC
Good Afternoon OC,
I carry an ancient ICOM IC-A3 transceiver in my emergency equipment pack.
It is powered by the optional battery pack that utilizes ten standard double A
batteries. I also carry a handheld GPS that is powered by double A
batteries. By carrying enough spare batteries to re-power both units I figure
I have
about as much back up communication and navigational capability as can be
had.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
________________________________________________________________________________
| From: | "Mark R Steitle" <mark.steitle(at)austin.utexas.edu> |
OC,
I did a search on "12v battery pack" on ebay and came up with many
items. This particular one comes with a carrying case, wall charger and
a cigarette lighter charger. See
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1502&item=5769065
615&rd=1#ebayphotohosting
Mark S.
So what I am looking for is a battery case with the following
characteristics:
1) Small light weight plastic.
2) Holds enough AA batteries to put out about 12 volts for a relatively
short period of time at a relatively light load.
3) Includes a cigarette lighter receptacle that one could plug an
adapter
cable into for powering 12 volt accessories like a hand held radio or
GPS.
I thought that surely something like this must exist, but after an hour
or
so on the internet last night I could not find such a critter. My
request to
you is: Does such a thing exist and how can I get one?
Any other thoughts?
OC
________________________________________________________________________________
| From: | <gmcjetpilot(at)yahoo.com> |
| Subject: | Transistors and Alternator OV |
Transistors and Alternator OV
It is true you can have a transistor "shorts, but not all transistors are the same,
not all applications are the same, and not all shorts are the same. The single
point argument against I-VR alternators is correct in theory, but there
are several factors that make this unlikely. You have one crankshaft in your plane.
They do fail but we trust they will not (unless you are flying one with
a known crank problem). This is why the transistor in you alternator (the single
point) should be very reliable. It is up to you to decide if this single "crankshaft"
(transistor) is good enough with out adding a second engine and flying
a twin.
Be careful drawing conclusions about transistor failures from other equipment.
How a transistor fails is dependent on how it is used. A stereo is not an alternator.
The transistor in a alternator may be running at 10% capacity Vs. some
hi-end stereo or power supply (depending on the kind of music you listen to)
near rated capacity. I don't know what is going thru the VR's field driver transistor,
but guess it is 2-3 amps or so. That is nothing, especially if you have
a heat sink. At 3 amps a heat sink is not even necessary, but adding one will
lower temps and increase reliability (of any transistor).
Transistors fail from getting to hot. Modern manufacturing makes transistors smaller,
more powerful and very reliable. Sudden shorts for no reason (like overload)
are rare. I will concede stuff happens. The electronic industry says transistors
are very reliable and any consumer of electronics will concur. TV's,
Microwave, cel phones work with out failure for 1000's of hours. Again you have
to be careful and compare apples to apples, but in general "semi-conductors"
are reliable if not abused. The how and why of failure is PHD land, but all we
need to know a transistor are as good as your crankshaft.
Type of transistors: The MOSFET (field effect transistor) is not a junction transistor.
How they fail is different. With that said, a MOSFET can fail (short)
in the way Bob says (drain to source). However it can fail in a multitude of
other ways, including just opening up. An "open" would cause the alternator to
just stop, a benign failure. How they are construction (type) and most important
how they are used determines reliability. That is why comparisons of transistors
in stereo is not truly valid, but it does point to the fact transistors
can fail. The MOSFET transistor in an alternator with PWM control is going to
be very efficient. I can take any electronic component and "blow it" by exceeding
its limitation. Like anything, operating with in the limits with margin will
keep safer.
This is one of the biggest things missed. THE transistor (driving the field) is
monitored by the IC chip. The IC is looking at the transistor's voltage in, out
and what it is being told to do. The IC looks at the transistors response,
shutting the door before a catastrophe transistor failure can happen. The IC knows
how that transistors should react and won't let it melt down (short). From
the reference I listed before, it is clear the IC circuit does monitor the transistor
for distress. Not only are transistors very reliable you have another
circuit monitoring it for one of the most common failures, a slow melt down.
Although I repeat a melt down at 2 amps is unlikely. Transistors at low power
are not just going to explode or short. Typically at low power they slowly degrade
in performance. That is what the IC detects, preventing any serious failure
by turning the alternator off. The IC is basically testing the transistor
continually. This is where the magic is if there is
any. The
IC will turn your alternator off and give you the "check alternator light". The
crow bar cant do this. Really transistors as old as the concept is, they are
still pretty amazing. Even more amazing is you can cram hundreds in a IC chip
and ask it to monitor, compare, check and regulate a system and it self.
A Denso VR assembly includes a sealed unit with heat sinks. As I said some alternators
use modules with no heat sink fins. No doubt the transistors in the other
brands are mounted in the module to transfer heat from the transistor to the
case, and in fact don't need a finned heat sink. A transistor has two ratings,
one with a heat sink and one with out. Not that the transistor in ND alternators
are more loaded, requiring a heat sink, they add them to improve reliability.
It cost more so some may not add it for cost savings or don't have the
room.
I suggest these units (ND) in their development were abused on test stands and
reliability was reached that was acceptable. I agree what is acceptable to an
automobile may not be acceptable to an aircraft. However as pointed out car electronics
also have serious need for a stable reliable voltage. I think what we
have now in the sate-of -art alternator with I-VR will be improved over the
next few years. Chance is these new modules, with even better protection and reliability,
will bolt into an existing alternator. For the quantum leap, I know
you could add redundant field control to an internal regulator. The cost is
not justified for the automotive industry at this time, but if a bunch of Lexus
or Mercedes-Benz start to fry electronics you will see this extra protection
sooner than later. Unfortunately it will be a new design, not an add on, beyond
the level of adding on a module.
Certification: I know it was said that an internal regulator could never be certified.
First being experimental is a badge of honor to me. Certification usually
involves telling the FAA "it is the same as this existing certified design".
The existing design can be bad, but as long as you are the same all is good.
If you cant say that, you try to prove that it cant fail or any failure is not
important and trivial to flight safety. Because GA airplanes have electrical
systems from the 50's or 60's (horrible), they use external regulators (and
add on OV protection sometimes). Trying to get the FAA to buy an IC circuit in
an internal regulator control may be swimming up stream. Does not mean it is
bad. Eventually it will happen if it has not already. If you installed dual internal
VR's with backup control of field power you might do it. Any takers; it
might cost a million dollars, but it will be great. To be fair to the FAA and
certification, not biting the hand that feed me, t
he
system works very well. This conservatism is what keeps the Gen public safe, but
it is at the cost of innovation and huge money to do anything different. That
is where experimental planes come in. May be not a revolution, just evolution.
Therefore I can feel good about using an alternator without the ass-on OV protection.
An IC has 100's of transistors. Some computer chips have millions or even hundreds
of millions of transistors. As I think it was said, ICs should be very reliable.
It is safe to say ICs that control things often have internal fault monitoring.
Forget about an almost impossible dual IC failure and Drive transistor
failure, the IC is very reliable. Any IC failure will no doubt be passive,
as the chip was designed. This self check logic is the same type that turns on
your cars warning lights (anti-lock, airbag, check engine).
Thanks for the great discussion, I agree that OV protection add ons are OK, and
should give you an extra level of comfort. However in my design goal, I am going
for the most simple system, light weight, ease of installation, that will
give me high reliability. Building and flying experimental planes, I can tell
you maintenance can suck the fun out of your flying. There will always be routine
and small items that are unavoidable, but the electrical system should be
one of the most reliable and maintenance free. Electrical gremlins suck. IN the
case of OV protection this is not a going to affect your reliability either
way, because it should be a rare event in any case. My only concern is a false
trip of a b-lead OV cutoff add-on may damage the I-VR or rectifier in alternator.
If you can assure high reliability, no false trips, you should have a very
reliable system. If the add-on system will add comfort to the builder/pilot,
it is good, but you have to stop with the add-ons at
some
point or you will end up with a twin-engine bi-plane. With or without will not
make much difference in most designs.
Thanks George
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
>
>
>OC,
>I did a search on "12v battery pack" on ebay and came up with many
>items. This particular one comes with a carrying case, wall charger and
>a cigarette lighter charger. See
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1502&item=5769065
>615&rd=1#ebayphotohosting
>
>Mark S.
>
>
>So what I am looking for is a battery case with the following
>characteristics:
>
>1) Small light weight plastic.
>
>2) Holds enough AA batteries to put out about 12 volts for a relatively
>short period of time at a relatively light load.
>
>3) Includes a cigarette lighter receptacle that one could plug an
>adapter
>cable into for powering 12 volt accessories like a hand held radio or
>GPS.
>
>I thought that surely something like this must exist, but after an hour
>or
>so on the internet last night I could not find such a critter. My
>request to
>you is: Does such a thing exist and how can I get one?
>
>Any other thoughts?
I try to avoid adding to the list of cockpit accessories
where ever possible. I fly with dual GPS310 receivers that
use AA batteries and my flight bag back-up is a JHP-520 that
gets new cells every year whether I turn it on or not. I put
new cells into both gps receivers outbound on a long trip
and new ones for the return. The DESIGN GOAL is to avoid
messing with batteries and battery boxes while in-flight . . .
ESPECIALLY in rough air or at night where risk of loosing
something on floor goes up.
Did an article on AA cells a few years ago at:
http://aeroelectric.com/articles/AA_Bat_Test.pdf which
was published in Sport Aviation. The driver for this
investigation was to see how to drive down battery
costs while elevating system reliability. I discovered
that the least expensive cells I could find were right
in the middle of industry average for energy contained
and the economics of running them until they died was
poor when compared with in-the-cockpit hazards.
I let my nieces and nephews have the used cells with
plenty of snort left in them and I never open a battery
box in flight. Would this modus operandi serve you
well also and eliminate the need for another flight-bag
accessory to guard against the dreaded dead-battery
syndrome?
Bob . . .
________________________________________________________________________________
| From: | Dj Merrill <deej(at)thayer.dartmouth.edu> |
| Subject: | Re: Battery Help |
Mark R Steitle wrote:
>
> OC,
> I did a search on "12v battery pack" on ebay and came up with many
> items. This particular one comes with a carrying case, wall charger and
> a cigarette lighter charger. See
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1502&item=5769065
> 615&rd=1#ebayphotohosting
>
> Mark S.
You can also find something similar at Walmart in the
automotive section. Sometimes called emergency power packs,
or boost packs. They don't take AA batteries, but
they are rechargeable with a standard 12v cigarette plug.
You can also use it to start the engine if the main
battery goes dead... :-)
-Dj
--
Dj Merrill
Sportsman 2+2 Builder #7118
"TSA: Totally Screwing Aviation"
________________________________________________________________________________
| From: | "Terry Watson" <terry(at)tcwatson.com> |
OC,
I have this gadget called a Coleman Powermate, 2" x 2-1/4" x 8" long, that
has a lighter plug on a cord about 18" long, and a lighter outlet in a
swivel head on the end of the main box. It has some nicad batteries sealed
inside. The idea is that you plug it in for awhile to charge it up, then
when you need power you can plug something into this unit. Or if your car
won't start, supposedly you can plug this thing in and it will over a few
minutes put some power back in the car's battery. It has an indicator light
on it.
I bought it at Costco maybe a year ago for maybe $20, but I haven't used it
other than play with it. It's been sitting on the shelf since then. I
think it's made for the application you are asking about.
The only additional information about model number on the case is 6969. I
think Coleman calls all of their electrical equipment Powermate. I couldn't
locate it on a quick Google search.
Terry
So what I am looking for is a battery case with the following
characteristics:
1) Small light weight plastic.
2) Holds enough AA batteries to put out about 12 volts for a relatively
short period of time at a relatively light load.
3) Includes a cigarette lighter receptacle that one could plug an adapter
cable into for powering 12 volt accessories like a hand held radio or GPS.
I thought that surely something like this must exist, but after an hour or
so on the internet last night I could not find such a critter. My request to
you is: Does such a thing exist and how can I get one?
Any other thoughts?
OC
________________________________________________________________________________
| From: | Harley <harley(at)AgelessWings.com> |
| Subject: | Re: Battery Help |
Evening, Terry...
Not sure where you got the 6969 from, but I believe that what you are
talking about is the Coleman Powermate Car Battery Booster. It's model
number is PMB8110
Searching on Google using that model number produces hundreds of places
selling it for anywhere from $20 to over $40.
Harley Dixon
Terry Watson wrote:
>
>OC,
>
>I have this gadget called a Coleman Powermate, 2" x 2-1/4" x 8" long, that
>has a lighter plug on a cord about 18" long, and a lighter outlet in a
>swivel head on the end of the main box. It has some nicad batteries sealed
>inside. The idea is that you plug it in for awhile to charge it up, then
>when you need power you can plug something into this unit. Or if your car
>won't start, supposedly you can plug this thing in and it will over a few
>minutes put some power back in the car's battery. It has an indicator light
>on it.
>
>I bought it at Costco maybe a year ago for maybe $20, but I haven't used it
>other than play with it. It's been sitting on the shelf since then. I
>think it's made for the application you are asking about.
>
>The only additional information about model number on the case is 6969. I
>think Coleman calls all of their electrical equipment Powermate. I couldn't
>locate it on a quick Google search.
>
>Terry
>
>So what I am looking for is a battery case with the following
>characteristics:
>
>1) Small light weight plastic.
>
>2) Holds enough AA batteries to put out about 12 volts for a relatively
>short period of time at a relatively light load.
>
>3) Includes a cigarette lighter receptacle that one could plug an adapter
>cable into for powering 12 volt accessories like a hand held radio or GPS.
>
>I thought that surely something like this must exist, but after an hour or
>so on the internet last night I could not find such a critter. My request to
>
>you is: Does such a thing exist and how can I get one?
>
>Any other thoughts?
>
>OC
>
>
>
>
________________________________________________________________________________
| Subject: | Re: Master/Starter Contactor connection bar |
Mathew,
I did the exact thing you did...built a one bar strap to connect the relay. When
the RV plans show a 2 bar! Further checking into resistance and load carrying
of the copper bar eased my mind. Yes - I will loose a tiny bit of voltage
when cranking. But so will the terminal ends, the other starter wires, the contactor,
etc. It won't crank long enough to heat the bar up. So I just left
it.
Kelly Patterson
PHX, AZ
RV-6A N716K FWF & Wiring (finally!)
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Master/Starter Contactor connection
-->
>
>
>Connected my starter and master contactor with a single piece of bus
>bar... should I use two pieces?
Don't know why you would need to. What are your concerns?
We often "bus" multiple devices that would normally accept
terminals for fat-wires.
If I understand your question, the pictures below
are illustrative of copper (or brass) straps used
to connect adjacent terminals of high current
carrying devices.
http://www.aeroelectric.com/Pictures/DISKA09F.JPG
http://www.aeroelectric.com/Pictures/DISKA11F.JPG
http://www.aeroelectric.com/Pictures/DISKA12F.JPG
Bob . . .
________________________________________________________________________________
| From: | Kevin Horton <khorton01(at)rogers.com> |
| Subject: | Autozone alternators |
>(Corvallis)"
>
>Wow...So I guess I'll fit the alternator and see if it dies?....Would
>you guys add the OVP as an external protection device just to be safe?
>
>What do you all think?
The risk of an overvoltage is low, but it is not zero. I have seen
more than one message on this list from people who experienced
overvoltage events. Only you can decide whether you are comfortable
with that risk, or whether you want to add overvoltage protection.
Adding overvoltage protection to an internally regulated alternator
can create new failure modes. There is some question about whether
the alternator B-lead contactor can be counted on to open in the
presence of an overvoltage.
For me, I would only risk using an internally regulated alternator if
my avionics didn't cost much. If I had invested more money in
avionics than I was prepared to lose, then I would spend the dollars
to get an externally regulated alternator with external overvoltage
protection. You don't necessarily have to spend the money to go with
B&C. There are recipes on the web which show how to modify some
automotive alternators to make them work with an external regulator
and overvoltage protection.
http://www.geocities.com/timrv6a/alternator.htm
How much will it cost you in money and time to replace your avionics
if they get toasted by an overvoltage?
How much will it cost you in money and time to add an external
regulator and overvoltage protection?
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
________________________________________________________________________________
aeroelectric-list(at)matronics.com
| From: | Neil K Clayton <harvey4(at)earthlink.net> |
| Subject: | Warning light press-to-test circuitry |
I'm struggling with a wiring issue involving panel warning lights;
Each warning light is part of a circuit between it's associated sensor and
ground. The warning lamps always have 12v applied to them. When the sensor
triggers, it connects the lamp to ground and the bulb illuminates. Easy!
I want to be able to touch a press-to-test button to test if the warning
lamps (or diodes in my case) are in fact working.
This involves a 2nd circuit between the press-to-test button and the lamp.
The button clamps the lamp to ground and the lamp lights. Right?
But...are here are my questions;
1) To only use one press-to-test button, I need all the lamps connected to
it, and by inference, to each other. But this same connection will
illuminate ALL the lamps when one is triggered for real by it's sensor. How
do I isolate the lamp for it's "everyday" purpose, but connect it to the
others for testing?
2) Connecting a lamp to ground for test purposes might have all sorts of
secondary effects on the sensors down the line. How do I disconnect the
sensor while grounding the lamp for test, then re-connect everything again
for everyday running?
Am I complicating this? I suspect I am but I can't see the wood for the trees!
Thanks
Neil
________________________________________________________________________________
| From: | "Brett Ferrell" <bferrell(at)123mail.net> |
| Subject: | Re: Warning light press-to-test circuitry |
Neil,
I did the same thing with my panel, I just installed some 276-1653 (the ones
I got were rated 3A) or similar in the "test" line to each lamp so that it's
"normal" function does not backfeed back to illuminate the other lamps. My
setup was slightly more complicated also because some of my lamps were
switched ground to illuminate and some were switched positive voltage.
Brett
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=276-1653
----- Original Message -----
From: "Neil K Clayton" <harvey4(at)earthlink.net>
Subject: AeroElectric-List: Warning light press-to-test circuitry
>
>
> I'm struggling with a wiring issue involving panel warning lights;
>
> Each warning light is part of a circuit between it's associated sensor and
> ground. The warning lamps always have 12v applied to them. When the sensor
> triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
> I want to be able to touch a press-to-test button to test if the warning
> lamps (or diodes in my case) are in fact working.
>
> This involves a 2nd circuit between the press-to-test button and the lamp.
> The button clamps the lamp to ground and the lamp lights. Right?
>
> But...are here are my questions;
>
> 1) To only use one press-to-test button, I need all the lamps connected
> to
> it, and by inference, to each other. But this same connection will
> illuminate ALL the lamps when one is triggered for real by it's sensor.
> How
> do I isolate the lamp for it's "everyday" purpose, but connect it to the
> others for testing?
>
> 2) Connecting a lamp to ground for test purposes might have all sorts of
> secondary effects on the sensors down the line. How do I disconnect the
> sensor while grounding the lamp for test, then re-connect everything again
> for everyday running?
>
> Am I complicating this? I suspect I am but I can't see the wood for the
> trees!
>
> Thanks
> Neil
>
>
>
________________________________________________________________________________
| From: | Robert McCallum <robert.mccallum2(at)sympatico.ca> |
| Subject: | Re: Warning light press-to-test circuitry |
Neil;
A handful of diodes will accomplish what you want. Connect the anode of
two diodes to each lamp where it originally went to the sensor. Connect
the cathode of one diode to the original sensor connection, connect the
cathode of all the remaining diodes (1 from each lamp) together and to
the push to test switch which you use to ground them all. Each light
then works normally on it's own and they all come on together when the
push to test grounds them. They do not interfere with each other nor do
you affect the sensor.
Bob McC
Neil K Clayton wrote:
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
________________________________________________________________________________
| From: | "Richard E. Tasker" <retasker(at)optonline.net> |
| Subject: | Re: Warning light press-to-test circuitry |
Use diodes. A set of two diodes for each lamp, anodes connected to the
ground end of the lamps (leave the 12V connected as is to the lamps).
Cathodes (typically indicated by a line on the cathode end of the diode)
of one of the diodes from each set connected to the switch and the other
side of the switch connected to ground. Cathode end of the other diode
of each set connected to the line that normally turns on the lamp.
Press the button and all lamps come on but the ground on the lamp is
isolated by the other diodes from the normal lamp actuator. Release the
button and all lamps work normally .
Dick Tasker
Neil K Clayton wrote:
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
--
----
Please Note:
No trees were destroyed in the sending of this message. We do concede, however,
that a significant number of electrons may have been temporarily inconvenienced.
----
________________________________________________________________________________
| From: | "Richard E. Tasker" <retasker(at)optonline.net> |
| Subject: | Re: Warning light press-to-test circuitry |
Oh, you can use a common garden variety 1N4001 (or one from that series)
for up to one amp lamps.
Dick Tasker
Neil K Clayton wrote:
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
--
----
Please Note:
No trees were destroyed in the sending of this message. We do concede, however,
that a significant number of electrons may have been temporarily inconvenienced.
----
________________________________________________________________________________
| From: | rv-9a-online <rv-9a-online(at)telus.net> |
| Subject: | Re: Warning light press-to-test circuitry |
Neil, you need a simple diode isolation circuit. Rather than describe
the circuit in detail, please go to
http://www3.telus.net/aviation/vx
and look for the IL-4A datasheet.
In the datasheet, you will see a schematic for the circuit and some
application notes. If you can't determine what's what, let me know
on-list and I'll put together some simpler information. Based on this,
you can wire up your circuit, or you can get an IL-4A that will do it
all for you.
The IL-4A senses ground-switched, +12V switched and reversing inputs
(flap motors, gear motors etc), provides push-to-test capability and
dimming capability for night operations.
Vern Little
RV-9A
Neil K Clayton wrote:
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
________________________________________________________________________________
| Subject: | Warning light press-to-test circuitry |
| From: | "Tim Dawson-Townsend" <Tdawson(at)avidyne.com> |
Given the reliability of LEDs, you could probably get away without a press-to-test
. . .
TDT
________________________________
From: owner-aeroelectric-list-server(at)matronics.com on behalf of Neil K Clayton
Subject: AeroElectric-List: Warning light press-to-test circuitry
I'm struggling with a wiring issue involving panel warning lights;
Each warning light is part of a circuit between it's associated sensor and
ground. The warning lamps always have 12v applied to them. When the sensor
triggers, it connects the lamp to ground and the bulb illuminates. Easy!
I want to be able to touch a press-to-test button to test if the warning
lamps (or diodes in my case) are in fact working.
This involves a 2nd circuit between the press-to-test button and the lamp.
The button clamps the lamp to ground and the lamp lights. Right?
But...are here are my questions;
1) To only use one press-to-test button, I need all the lamps connected to
it, and by inference, to each other. But this same connection will
illuminate ALL the lamps when one is triggered for real by it's sensor. How
do I isolate the lamp for it's "everyday" purpose, but connect it to the
others for testing?
2) Connecting a lamp to ground for test purposes might have all sorts of
secondary effects on the sensors down the line. How do I disconnect the
sensor while grounding the lamp for test, then re-connect everything again
for everyday running?
Am I complicating this? I suspect I am but I can't see the wood for the trees!
Thanks
Neil
________________________________________________________________________________
| From: | rv-9a-online <rv-9a-online(at)telus.net> |
| Subject: | Re: Warning light press-to-test circuitry |
Two other functions of press-to-test:
Test the dimmer level for night time operation. It's very important
that the warning lights be visible at night (dimmer not too low).
Test the circuit breaker/fuse that drives the warning lamp circuits.
By the way... LED's fail mostly due to mechanical reasons (lead stress),
but they do fail.
Vern Little
Tim Dawson-Townsend wrote:
>
>
>Given the reliability of LEDs, you could probably get away without a press-to-test
. . .
>
>TDT
>
>
>________________________________
>
>From: owner-aeroelectric-list-server(at)matronics.com on behalf of Neil K Clayton
>To: canard-aviators(at)yahoogroups.com; Cozy_Builders(at)mailman.qth.net; aeroelectric-list(at)matronics.com
>Subject: AeroElectric-List: Warning light press-to-test circuitry
>
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
________________________________________________________________________________
| From: | "tonybabb" <tonybabb(at)alejandra.net> |
| Subject: | Re: Warning light press-to-test circuitry |
I'm electrically challenged so sorry if this is a dumb question but ....why
two diodes? I can see why you'd want a diode between the Push-to-test switch
and the lamp (because all the lamps would be connected together and you
don't want one turning on the others) but why another diode between the lamp
and whatever normally grounds it.
Thanks,
Tony Velocity SEFG
62% done, 78% to go.
----- Original Message -----
From: "Richard E. Tasker" <retasker(at)optonline.net>
Subject: Re: AeroElectric-List: Warning light press-to-test circuitry
>
> Use diodes. A set of two diodes for each lamp, anodes connected to the
> ground end of the lamps (leave the 12V connected as is to the lamps).
> Cathodes (typically indicated by a line on the cathode end of the diode)
> of one of the diodes from each set connected to the switch and the other
> side of the switch connected to ground. Cathode end of the other diode
> of each set connected to the line that normally turns on the lamp.
>
> Press the button and all lamps come on but the ground on the lamp is
> isolated by the other diodes from the normal lamp actuator. Release the
> button and all lamps work normally .
>
> Dick Tasker
>
> Neil K Clayton wrote:
>
> >
> >I'm struggling with a wiring issue involving panel warning lights;
> >
> >Each warning light is part of a circuit between it's associated sensor
and
> >ground. The warning lamps always have 12v applied to them. When the
sensor
> >triggers, it connects the lamp to ground and the bulb illuminates. Easy!
> >
> >I want to be able to touch a press-to-test button to test if the warning
> >lamps (or diodes in my case) are in fact working.
> >
> >This involves a 2nd circuit between the press-to-test button and the
lamp.
> >The button clamps the lamp to ground and the lamp lights. Right?
> >
> >But...are here are my questions;
> >
> >1) To only use one press-to-test button, I need all the lamps connected
to
> >it, and by inference, to each other. But this same connection will
> >illuminate ALL the lamps when one is triggered for real by it's sensor.
How
> >do I isolate the lamp for it's "everyday" purpose, but connect it to the
> >others for testing?
> >
> >2) Connecting a lamp to ground for test purposes might have all sorts of
> >secondary effects on the sensors down the line. How do I disconnect the
> >sensor while grounding the lamp for test, then re-connect everything
again
> >for everyday running?
> >
> >Am I complicating this? I suspect I am but I can't see the wood for the
trees!
> >
> >Thanks
> >Neil
> >
> >
> >
> >
>
> --
> ----
> Please Note:
> No trees were destroyed in the sending of this message. We do concede,
however,
> that a significant number of electrons may have been temporarily
inconvenienced.
> ----
>
>
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
AeroElectric-List message previously posted by: BobsV35B(at)aol.com
<>
AeroElectric-List message previously posted by: "Robert L. Nuckolls, III"
<>
4/29/2005
Hello Old Bob and Bob Nuckolls, Thanks for your inputs -- I agree with your
philosophy of using conforming AA battery packs either for primary power or
to back up ni cads. That is how I back up the ni cad battery in my ICOM A-4
hand held when I am flying my KIS TR-1.
Unfortunately there is no conforming AA battery pack available, that I could
find, that would fit my friends rather ancient Garmin GPS Comm so some sort
of jury rig arrangement appears to be the best situation. Buying a new ni
cad battery for the unit I think is still possible, but very expensive and
again in a few years would be of doubtful reliability.
I'll address in a separate posting to the list some of the other solutions
offered.
OC
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
| Subject: | Battery Help Solutions |
AeroElectric-List message previously posted by: "Mark R Steitle"
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1502&item=5769065
615&rd=1#ebayphotohosting>
Mark S.>>
4/29/2005
Hello Mark, Thanks for your input. I have not yet learned to speak ebay.
Some comments on that item: It looks like it would do the job. Could not get
a feel for the size and weight. It claims the buyer can replace the battery,
but provides no info on what the battery is. May be a bit pricey -- one
could buy just a small 12v battery, some cigarette lighter socket adapters
from Radio Shack and rig something both smaller, lighter, and cheaper.
There does appear to be a profusion of 12 volt battery packs available, but
it is hard to determine if they would be suitable in the cockpit.
OC
Next item suggested thanks to Dj Merrill, Terry Watson, and Harley Dixon was
the Coleman Powermate Car Battery Booster model number PMB8110. Looks like
it also would do the job. May be an overkill in the weight and size
department. Could not get that data from the web. I am still leary of
depending upon ni cad batteries when reliability of performance is the goal.
OC
Final solution? Right now I am leaning towards a Panasonic (or comparable)
12 volt VRLA battery LC-R121R3P which is relatively inexpensive, small,
light (1.3 LBS), and rechargable. It could be hooked up for both recharging
and use with some PN 270-1590 and PN 270-1527 lighter plug and socket
adapters from Radio Shack, some Fast on terminals,and a few minutes work
with stripper and crimper.
OC
________________________________________________________________________________
| From: | Richard Tasker <retasker(at)optonline.net> |
| Subject: | Re: Warning light press-to-test circuitry |
They are probably not necessary, but they do isolate the individual lamp
actuators from the lamp test switch.
It is possible (but probably not likely) that one of the devices that
normally actuate the lamps could be damaged if it were grounded with the
test switch while it wanted the lamp to be off.
Dick Tasker
tonybabb wrote:
>
>I'm electrically challenged so sorry if this is a dumb question but ....why
>two diodes? I can see why you'd want a diode between the Push-to-test switch
>and the lamp (because all the lamps would be connected together and you
>don't want one turning on the others) but why another diode between the lamp
>and whatever normally grounds it.
>
>Thanks,
>
>Tony Velocity SEFG
>62% done, 78% to go.
>----- Original Message -----
>From: "Richard E. Tasker" <retasker(at)optonline.net>
>To:
>Subject: Re: AeroElectric-List: Warning light press-to-test circuitry
>
>
>
>
>>
>>
>
>
>
>>Use diodes. A set of two diodes for each lamp, anodes connected to the
>>ground end of the lamps (leave the 12V connected as is to the lamps).
>>Cathodes (typically indicated by a line on the cathode end of the diode)
>>of one of the diodes from each set connected to the switch and the other
>>side of the switch connected to ground. Cathode end of the other diode
>>of each set connected to the line that normally turns on the lamp.
>>
>>Press the button and all lamps come on but the ground on the lamp is
>>isolated by the other diodes from the normal lamp actuator. Release the
>>button and all lamps work normally .
>>
>>Dick Tasker
>>
>>Neil K Clayton wrote:
>>
>>
>>
>>>
>>>
>
>
>
>>>I'm struggling with a wiring issue involving panel warning lights;
>>>
>>>Each warning light is part of a circuit between it's associated sensor
>>>
>>>
>and
>
>
>>>ground. The warning lamps always have 12v applied to them. When the
>>>
>>>
>sensor
>
>
>>>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>>>
>>>I want to be able to touch a press-to-test button to test if the warning
>>>lamps (or diodes in my case) are in fact working.
>>>
>>>This involves a 2nd circuit between the press-to-test button and the
>>>
>>>
>lamp.
>
>
>>>The button clamps the lamp to ground and the lamp lights. Right?
>>>
>>>But...are here are my questions;
>>>
>>>1) To only use one press-to-test button, I need all the lamps connected
>>>
>>>
>to
>
>
>>>it, and by inference, to each other. But this same connection will
>>>illuminate ALL the lamps when one is triggered for real by it's sensor.
>>>
>>>
>How
>
>
>>>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>>>others for testing?
>>>
>>>2) Connecting a lamp to ground for test purposes might have all sorts of
>>>secondary effects on the sensors down the line. How do I disconnect the
>>>sensor while grounding the lamp for test, then re-connect everything
>>>
>>>
>again
>
>
>>>for everyday running?
>>>
>>>Am I complicating this? I suspect I am but I can't see the wood for the
>>>
>>>
>trees!
>
>
>>>Thanks
>>>Neil
>>>
>>>
>>>
>>>
>>>
>>>
>>--
>>----
>>Please Note:
>>No trees were destroyed in the sending of this message. We do concede,
>>
>>
>however,
>
>
>>that a significant number of electrons may have been temporarily
>>
>>
>inconvenienced.
>
>
>>----
>>
>>
>>
>>
>
>
>
>
________________________________________________________________________________
| Subject: | Re: Battery Help |
| From: | "Matt Prather" <mprather(at)spro.net> |
Is there any chance you could disect the battery pack you have and repopulate
it with new batteries?
Matt-
>
> Hello Old Bob and Bob Nuckolls, Thanks for your inputs -- I agree with
> your philosophy of using conforming AA battery packs either for primary
> power or to back up ni cads. That is how I back up the ni cad battery
> in my ICOM A-4 hand held when I am flying my KIS TR-1.
>
> Unfortunately there is no conforming AA battery pack available, that I
> could find, that would fit my friends rather ancient Garmin GPS Comm so
> some sort of jury rig arrangement appears to be the best situation.
> Buying a new ni cad battery for the unit I think is still possible, but
> very expensive and again in a few years would be of doubtful
> reliability.
>
> I'll address in a separate posting to the list some of the other
> solutions offered.
>
> OC
>
>
________________________________________________________________________________
| From: | flmike <flmike2001(at)yahoo.com> |
| Subject: | Re: Warning light press-to-test circuitry |
Neil,
See if this ASCII schematic comes through.
Mike
+12V----lamp--------sensor switch -------gnd
|
+---------|>|----------------------
(1N4001 rectifier) |
|
+12V----lamp--------sensor switch -------gnd |
| |
+---------|>|----------------------
|
|
+12V----lamp--------sensor switch -------gnd |
| |
+---------|>|----------------------
|
|
+12V----lamp--------sensor switch -------gnd |
| |
+---------|>|----------------------
|
|
Normally
open
PTT
switch
|
gnd
________________________________________________________________________________
| From: | sportav8r(at)aol.com |
| Subject: | source for S700 series switches |
Besides B & C, where can I shop for S700 series / Carling / C&H switches? I'm
compiling a vendor list before embarking on a total re-do of my panel (now that
I've read the 'Connection)
-Stormy
________________________________________________________________________________
| From: | Robert McCallum <robert.mccallum2(at)sympatico.ca> |
| Subject: | Re: Warning light press-to-test circuitry |
Part of the concern posed in the original question was to prevent the
push to test switch feeding back into the "normal" sensors for the
light. The second diode accomplishes this part of the requested task.
Bob McC
tonybabb wrote:
>
>I'm electrically challenged so sorry if this is a dumb question but ....why
>two diodes? I can see why you'd want a diode between the Push-to-test switch
>and the lamp (because all the lamps would be connected together and you
>don't want one turning on the others) but why another diode between the lamp
>and whatever normally grounds it.
>
>Thanks,
>
>Tony Velocity SEFG
>
>
________________________________________________________________________________
| From: | Fiveonepw(at)aol.com |
| Subject: | Re: Warning light press-to-test circuitry |
In a message dated 04/29/2005 12:15:01 PM Central Standard Time,
retasker(at)optonline.net writes:
do I isolate the lamp for it's "everyday" purpose, but connect it to the
>>>others for testing?
>>>>
Went through the same concern while planning my LED annunciator panel. Asked
the same question on the A-list and Bob N. reminded me that during normal
power up and engine start, most annunciators "should" activate in one fasion or
another, telling you the lights are working plus provide real-world operational
checks as well. (which is why they're there anyway!) Master on = oil p,
alt, flaps, canopy and EIS warning all active, flaps up turns that one of, ditto
for canopy latched. Engine start knocks out the rest for a clean annunciator
for taxi. Put the items of interest on your checklist and launch. If any
particular light does or does not light when appropriate, good time to shut down
and investigate. Has worked very well for me after 175 hours...
But then you could always rig up some (ughh!) multi-pole relays for PTT
grounds...
Mark Phillips -6A
________________________________________________________________________________
| From: | <gmcjetpilot(at)yahoo.com> |
| Subject: | Re: Internally regulated alternator OVP protection |
THANKS BOB, Great reply. The whole purpose of this discussion is not to worship
auto technology, but to know what you are praying for if you choose to sit in
that church pew.
One-liners: regarding auto alternators (voltage regulator) in your airplane:
-Power system test demonstrated 4.6 million hours MTBF (electronic)
-Expect a min 1/2 million hours MTBF (mean time between failure)
-Internal alternators incorporate a fuse that prevents alternator from melt down
if an OV condition occurs, protecting the airframe, but it may not act fast
enough to prevent avionics equip damage.
Bob, you asked 2 questions or clarifications:
>I didn't see that the IC knows anything about impending failures?
You are correct; nothing says it will predict a transistor is about to fail, as
I indicated. **However, the VR in the ND does have Over Voltage protection, as
do many I-VRs.**
If I have to make one point, internal VR do have OV protection. The question of
how effective or how they work is still up for debate. What does that mean?
I have to assume when over voltage is sensed (17V) the IC will try to shut the
field (MOSFET) down. So if the OV is the symptom of a FET failure, than yes it
will detect a failure, but agreed this is not very predictive. Also the rotor
short protection (detection) although not a direct indication of the FET shorting
as I might have assumed, I wonder if a FET failure could appear as a field
short (ie increasing field current like a field short).
>Where in the narrative do we find a feature that "senses impending overload"?
Predictive (impending) over load/temp may be overstating it. Besides the obvious
normal functions of any VR limiting voltage, there are references made to current
limiting and thermal-overload protection. I recall ND propaganda referring
to reducing alternator output in the event it becomes over heated, but I cant
find the specific technical reference, other than vague terms. Thermal protection
of what: IC, field driver transistor or alternator output rectifier? Many
ICs do have internal thermal shut down protection. Is that a function of alternator
over load? Could be. I found details that support thermal protection
and shut down of a power MOSFET by an IC for other applications, including stereos,
but nothing specific about this in alternator applications. Since FET failures
are preceded with increasing temp this could be somewhat predictive. Whether
any I-VR has thermal protection or not, I don't know, but it is well with
in the capabilities of off the shelf components
to do
this, just might not be cost effective for auto applications. (Keep your alternator
as cool as you reasonably can).
Quote: A power MOSFET contains thousands of parallel devices that are internal,
and you cannot individually protect them. This situation is similar to the well-known
phenomenon of secondary breakdown and you can take steps to avoid its
destruction. One way to overcome this problem is to directly sense the temperature
of the MOSFET by integrating the MOSFET with the controller, and the temperature
can be sensed directly on the FET die.
http://wind.eecs.berkeley.edu/~nesgaard/PATH%20Report%20on%20Power%20System%20Reliability.pdf
Data quoted for reliability of electronic components for individual components
and as a system. This ref is EXCELLENT, directly dealing with the topic at hand,
"power system reliability" (with an eye on protection of unbelievably advanced
automotive electronics which affects safety) Apparently auto technology in
the future will have active electronics with communication links, steering actuation
and collision avoidance using radar and Liar -Light Detection And Ranging!
Note: FIT (Failure In Time -billions hrs).
http://www.koaproducts.com/english/application/ap7.htm
The ND I have, uses a current limit / fusing device; unfortunately its not a diode
as you speak of. From the Berkeley ref above, it points to the fact this kind
of device has a disadvantage in that they can withstand currents 10 times
their normal rating for prolonged time (a fraction of a second?). To get the recommend
1ms failure the fuse cant have more than 4 times norm capacity. So as
an absolute back up to save your avionics from OV, it is not going to help much;
however, it will assure the alternator will die at some point, sooner than
later without catching on fire. Which is real important to anyone using a ND
alternator.
http://www.irf.com/technical-info/whitepaper/s30p5.pdf
Interesting very technical and over my head, but excelling graphical illustration
representing the internal flow inside a FET in failure modes. The main point
is a FET failure is not just one internal event, but also many secondary events.
Apparently the new L MOSFETs are more resilient, but my 25-year-old Pioneer
Stereo (65watt x 2), with MOSFET transistors is still kicking.
Thanks Bob, for giving your insight. When it comes to little alternators with I-VR,
first I can trust that it will NOT cause danger to the aircraft. However
equipment damage "avionics" is *possible* as you and others have stated. With
that said, understanding of *how possible* will help make an informed choice.
I can accept the risk of using a I-VR without extra OV protection since MTBF
is between 200,000-500,000 hours. If I had $30,000 of avionics I would also consider
using additional OV protection, it is more insurance. However, depending
on your design goals, a stand alone I-VR alternator can provide a very good
level of reliability and simplicity. Also, use of standard auto parts may help
on the road if you need to replace it.
Thanks George
________________________________________________________________________________
| From: | Steve Goldman <steve(at)fatcatair.com> |
| Subject: | Re: Internally regulated alternator OVP protection |
clamav-milter version 0.80j
on hestia
gmcjetpilot(at)yahoo.com wrote:
>
> I have to assume when over voltage is sensed (17V) the IC will try to shut the
field (MOSFET) down. So if the OV is the symptom of a FET failure, than yes
it will detect a failure, but agreed this is not very predictive. Also the rotor
short protection (detection) although not a direct indication of the FET shorting
as I might have assumed, I wonder if a FET failure could appear as a field
short (ie increasing field current like a field short).
>
>
I would hope that this is not the only thing the OVP is trying to do. The reason
the
voltage is over spec is that the regulator, which is controlling that very same
transistor to modulate field currents, is not able to do its job.
For the OVP design to assume that the reason the OV condition exists is that the
rest of the
regulator itself is failing but that the hardest working component in the regulator
is still functional would be serious design mistake. It wouldn't be a mistake for
the OVP circuitry to try this, but it would be a mistake if it was its only recourse.
--
Steve
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: source for S700 series switches |
>
>
>Besides B & C, where can I shop for S700 series / Carling / C&H
>switches? I'm compiling a vendor list before embarking on a total re-do
>of my panel (now that I've read the 'Connection)
>-Stormy
Get on the Internet . . . there are dozens of major parts houses
and thousands of minor sources. The big guys are Allied, Newark,
Digikey, Hosfelt, Mouser, Halted Specialties, etc.
Take care lest the $time$ you spend trying to optimize your
purchasing dollar dilute the value of dollar because of the
$time$ you spend.
At every opportunity to do a skunk works project for RAC,
I will order materials on my credit card from one of the
BIG guys and ask for overnight shipping. I don't even
wait until the whole list of parts are identified. I and
my techs will any quantity and kind of item as soon as
the need is identified.
On one particularly hurry-up project a few years ago
my local purchasing guy got wind of what I was doing and
wrote my boss a rather terse memo. He was upset that I
was "paying $15 overnight charges (and sometimes $5 extra
on orders under $25) just to get around the value
of his services". When the dust settled on the job, I
looked at all of our orders which totaled just over 20.
Assuming we paid the worst possible penalties for each
order, my shipping overhead for the task was about $400.
We had the parts delivered to my front doorstep so nothing
got lost in receiving and no RAC folks touched the parts
thus adding more overhead $time$. We figure it
costs RAC about $250 just to process the paper for one
minimal purchase order and even then, we can only purchase
materials from 'approved' suppliers. Some of my favorite
suppliers were not on RACs approved list.
Bottom line was that the shortest and least costly
distance between needing and receiving was my
credit card and keyboard. Every other 'service'
offered only made the task more difficult (it takes
as much no-value-added time to fill out a purchase
request as it did to place the order ourselves). It was
also risky (little packages get lost in the mountain
of incoming freight) and expensive in terms of other
$time$ adders (the receiving dock was 7 miles from my
lab). My boss apologized for upsetting the gentleman
but reminded him that our customer expected the very
best we could offer in terms of delivery and that the
'system', while useful for buying trainloads of rivets
and aluminum, simply did not make sense for the task at hand.
If you enjoy this kind of exercise, by all means, have
at it. This IS after all, just an expensive hobby.
However, if your task is to produce a product to your
design goals in with a minimum expenditure of total $time$
then $time$ spent to save $time$ may not be adding value
to your effort.
Bob . . .
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
AeroElectric-List message previously posted by: "Matt Prather"
<>
4/30/2005
Hello Matt, Thanks for your input -- I'll suggest that to my friend. I know
that other people have used that method on other battery powered units such
as cordless drills, etc.
Some of the ni cad battery cases on the hand held avionics units are so well
put together / molded that dissecting them constitutes near destruction of
the battery case. From a volume and voltage aspect stuffing the right amount
of alkaline or other batteries inside the ni cad case and making the proper
electrical connections could be a challenge. Also some of the ni cad battery
cases are so integral to the shape of the hand held unit that the presence
of the designed battery case is essential to the handling / fastening / use
of the hand held unit.
I think my friend is actually lucky that he can power his Garmin GPS Comm
with a cigarette lighter cord. I don't have any such provision on my ICOM
IC-A4. Attaching a battery case with either the designed ni cad or alkaline
batteries appears to be the only option for operation of that unit.
OC
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: Internally regulated alternator OVP protection |
I would tend to think that if such fusing really exists and is
intentional - it is there because the designer considers that the
possiblility of an uncontrolled alternator runaway is significant enough
to warrant it...
Ken
>-Internal alternators incorporate a fuse that prevents alternator from melt down
if an OV condition occurs, protecting the airframe, but it may not act fast
enough to prevent avionics equip damage.
>
>snip
>
>The ND I have, uses a current limit / fusing device; unfortunately its not a diode
as you speak of. From the Berkeley ref above, it points to the fact this
kind of device has a disadvantage in that they can withstand currents 10 times
their normal rating for prolonged time (a fraction of a second?). To get the
recommend 1ms failure the fuse cant have more than 4 times norm capacity. So as
an absolute back up to save your avionics from OV, it is not going to help much;
however, it will assure the alternator will die at some point, sooner than
later without catching on fire. Which is real important to anyone using a ND
alternator.
>
>
>snip
>
>
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: Internally regulated alternator OVP protection |
clamav-milter version 0.80j on hestia
Hi Steve
Yes that is precisely the main point. There is no other part in there
that we know of capable of reducing the field current before the voltage
gets out of hand. It might be oversized, have temperature protection,
and not be highly stressed in the newer designs though...
Ken
Steve Goldman wrote:
>
>gmcjetpilot(at)yahoo.com wrote:
>
>
>
>>I have to assume when over voltage is sensed (17V) the IC will try to shut the
field (MOSFET) down. So if the OV is the symptom of a FET failure, than yes
it will detect a failure, but agreed this is not very predictive. Also the rotor
short protection (detection) although not a direct indication of the FET shorting
as I might have assumed, I wonder if a FET failure could appear as a field
short (ie increasing field current like a field short).
>>
>>
>>
>>
>I would hope that this is not the only thing the OVP is trying to do. The reason
the
>voltage is over spec is that the regulator, which is controlling that very same
>transistor to modulate field currents, is not able to do its job.
>
>For the OVP design to assume that the reason the OV condition exists is that the
rest of the
>regulator itself is failing but that the hardest working component in the regulator
>is still functional would be serious design mistake. It wouldn't be a mistake
for
>the OVP circuitry to try this, but it would be a mistake if it was its only recourse.
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Warning light press-to-test circuitry |
>
>In a message dated 04/29/2005 12:15:01 PM Central Standard Time,
>retasker(at)optonline.net writes:
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
> >>>others for testing?
> >>>>
>
>Went through the same concern while planning my LED annunciator panel. Asked
>the same question on the A-list and Bob N. reminded me that during normal
>power up and engine start, most annunciators "should" activate in one
>fasion or
>another, telling you the lights are working plus provide real-world
>operational
>checks as well. (which is why they're there anyway!) Master on = oil p,
>alt, flaps, canopy and EIS warning all active, flaps up turns that one of,
>ditto
>for canopy latched. Engine start knocks out the rest for a clean annunciator
>for taxi. Put the items of interest on your checklist and launch. If any
>particular light does or does not light when appropriate, good time to
>shut down
>and investigate. Has worked very well for me after 175 hours...
I've been watching this thread and I believe the majority
of salient points have been covered. Thanks to all the participants.
I'll only add to the discussion with a review of the history
of press-to-test for lamp driven annunciators.
The P-t-T fixture has been around since WWII. There first were
single lamp holders with various colors for lenses and a MECHANICAL
shutter for dimming. Here's a modern, miniature version.
http://www.aeroelectric.com/Pictures/PTT_Dim_Fixture.jpg
I have one of ol' boss hogg fixtures from the WWII era
around here somewhere but couldn't put my hands on it in
time for this picture. Maybe later.
Anywho, this clever product allowed installation of individual
annunciator/indicator lamps as needed and provided dimming
and testing in the one package. Cool.
The thrust of wanting to test back then was that incandescent
lamps were known to burn out. They had limited service
lives. Further, since each fixture had but one lamp, it
was useful to be able to push the fixture to test lamp
integrity at any time.
Over the years, individual incandescent fixtures were
replaced with arrays of lighted screens with various
legends to inform/warn pilots of some activity. We
put TWO lamps into each fixture so as to eliminate
the possibility that loss of one lamp would mean loss
of that informative function.
Keep in mind that local PTT functions do but one thing,
prove integrity of the lamp. You can have wiring and
all manner of sensors and switches go bad such that
you loose one annunciator. Pressing a button to see
all the lights come on may be reassuring to some but
it tests only a tiny fraction of the whole system . . .
light bulbs.
When I design important electro-whizzies, there's a
test input pin that can be exercised with a push-button
on the panel. I use this input as a command to do
as much INTERNAL VERIFICATION OF FUNCTIONALITY as
possible. Hitting the PTT button and getting some
predictable behavior from the annunciator has much
a great deal more meaning and assurance of system
integrity.
In the mean time, very long lived LEDs have replaced
the limited life lamps for annunciation and indication.
But the PTT button for testing lamps seems to have
persisted. I'll suggest that unless a proposed PTT
system does more than illuminate LEDs, that adding
the PTT system reduces reliability (lots of extra
wiring, diodes, etc), increases $time$ to fabricate
and install the system and ultimately tells you
nothing of interest when you push the button.
Bob . . .
________________________________________________________________________________
| Subject: | Re: Battery Help |
| From: | Gerry Holland <gnholland(at)onetel.com> |
>
> AeroElectric-List message previously posted by: "Matt Prather"
>
>
> < repopulate
> it with new batteries? Matt>>
>
> 4/30/2005
>
> Hello Matt, Thanks for your input -- I'll suggest that to my friend. I know
Hi!
> I don't have any such provision on my ICOM
> IC-A4. Attaching a battery case with either the designed ni cad or alkaline
> batteries appears to be the only option for operation of that unit.
I think you can. Use:
CP-12/L CIGARETTE LIGHTER CABLE WITH NOISE FILTER: Allows you to charge the
connected battery pack (13.5 to 16 V DC required). For charging ONLY -- the
transceiver cannot be simultaneously operated.
With both A4 and A5 it will charge and be usable to so dont know why it
carries that warning.
Or wire in a supply permanently to your aircraft using:
OPC-254/L DC POWER CABLE: Allows you to charge the connected battery pack
(13.5 to 16 V DC required).
Useful if you want the A4 as a backup and always to be charged when in
Aircraft. It is a pain that you cannot switch on whilst charging.
I have superceded my A4 with an A5 but did use the Cigarette lighter power
input with both.
Regards
Gerry
________________________________________________________________________________
| Subject: | Re: Internally regulated alternator OVP protection |
| From: | "George Braly" <gwbraly(at)gami.com> |
After all of this, the one simple fact remains:
If the FET (or other transistor) switching the field fails in the normal way those
components fail (shorted) - - you will have an uncontrolled runaway alternator.
At this point, there is really not much more to be said about the issue. The
internally regulated automotive alternators have a known single point failure
mode that is unacceptable in normal aircraft design circles.
If people crashed when alternators failed - - it would be unacceptable for the
automotive world, too.
That is the distinction, and it makes all of the difference.
Regards, George
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of gmcjetpilot(at)yahoo.com
Subject: AeroElectric-List: Re: Internally regulated alternator OVP protection
THANKS BOB, Great reply. The whole purpose of this discussion is not to worship
auto technology, but to know what you are praying for if you choose to sit in
that church pew.
One-liners: regarding auto alternators (voltage regulator) in your airplane:
-Power system test demonstrated 4.6 million hours MTBF (electronic)
-Expect a min 1/2 million hours MTBF (mean time between failure)
-Internal alternators incorporate a fuse that prevents alternator from melt down
if an OV condition occurs, protecting the airframe, but it may not act fast
enough to prevent avionics equip damage.
Bob, you asked 2 questions or clarifications:
>I didn't see that the IC knows anything about impending failures?
You are correct; nothing says it will predict a transistor is about to fail, as
I indicated. **However, the VR in the ND does have Over Voltage protection, as
do many I-VRs.**
If I have to make one point, internal VR do have OV protection. The question of
how effective or how they work is still up for debate. What does that mean?
I have to assume when over voltage is sensed (17V) the IC will try to shut the
field (MOSFET) down. So if the OV is the symptom of a FET failure, than yes it
will detect a failure, but agreed this is not very predictive. Also the rotor
short protection (detection) although not a direct indication of the FET shorting
as I might have assumed, I wonder if a FET failure could appear as a field
short (ie increasing field current like a field short).
>Where in the narrative do we find a feature that "senses impending overload"?
Predictive (impending) over load/temp may be overstating it. Besides the obvious
normal functions of any VR limiting voltage, there are references made to current
limiting and thermal-overload protection. I recall ND propaganda referring
to reducing alternator output in the event it becomes over heated, but I cant
find the specific technical reference, other than vague terms. Thermal protection
of what: IC, field driver transistor or alternator output rectifier? Many
ICs do have internal thermal shut down protection. Is that a function of alternator
over load? Could be. I found details that support thermal protection
and shut down of a power MOSFET by an IC for other applications, including stereos,
but nothing specific about this in alternator applications. Since FET failures
are preceded with increasing temp this could be somewhat predictive. Whether
any I-VR has thermal protection or not, I don't know, but it is well with
in the capabilities of off the shelf components
to do
this, just might not be cost effective for auto applications. (Keep your alternator
as cool as you reasonably can).
Quote: A power MOSFET contains thousands of parallel devices that are internal,
and you cannot individually protect them. This situation is similar to the well-known
phenomenon of secondary breakdown and you can take steps to avoid its
destruction. One way to overcome this problem is to directly sense the temperature
of the MOSFET by integrating the MOSFET with the controller, and the temperature
can be sensed directly on the FET die.
http://wind.eecs.berkeley.edu/~nesgaard/PATH%20Report%20on%20Power%20System%20Reliability.pdf
Data quoted for reliability of electronic components for individual components
and as a system. This ref is EXCELLENT, directly dealing with the topic at hand,
"power system reliability" (with an eye on protection of unbelievably advanced
automotive electronics which affects safety) Apparently auto technology in
the future will have active electronics with communication links, steering actuation
and collision avoidance using radar and Liar -Light Detection And Ranging!
Note: FIT (Failure In Time -billions hrs).
http://www.koaproducts.com/english/application/ap7.htm
The ND I have, uses a current limit / fusing device; unfortunately its not a diode
as you speak of. From the Berkeley ref above, it points to the fact this kind
of device has a disadvantage in that they can withstand currents 10 times
their normal rating for prolonged time (a fraction of a second?). To get the recommend
1ms failure the fuse cant have more than 4 times norm capacity. So as
an absolute back up to save your avionics from OV, it is not going to help much;
however, it will assure the alternator will die at some point, sooner than
later without catching on fire. Which is real important to anyone using a ND
alternator.
http://www.irf.com/technical-info/whitepaper/s30p5.pdf
Interesting very technical and over my head, but excelling graphical illustration
representing the internal flow inside a FET in failure modes. The main point
is a FET failure is not just one internal event, but also many secondary events.
Apparently the new L MOSFETs are more resilient, but my 25-year-old Pioneer
Stereo (65watt x 2), with MOSFET transistors is still kicking.
Thanks Bob, for giving your insight. When it comes to little alternators with I-VR,
first I can trust that it will NOT cause danger to the aircraft. However
equipment damage "avionics" is *possible* as you and others have stated. With
that said, understanding of *how possible* will help make an informed choice.
I can accept the risk of using a I-VR without extra OV protection since MTBF
is between 200,000-500,000 hours. If I had $30,000 of avionics I would also consider
using additional OV protection, it is more insurance. However, depending
on your design goals, a stand alone I-VR alternator can provide a very good
level of reliability and simplicity. Also, use of standard auto parts may help
on the road if you need to replace it.
Thanks George
---
---
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Apex NC seminar June 4/5 |
Due to a blessedly temporary crash of the gray matter soft-drive,
we pulled the plug prematurely on the Apex NC seminar on June 4/5.
I've spoken with and/or e-mailed all the folks who were signed up for
that program to let them know that we've had a successful re-boot
and the REAL go/no-go date for the program is May 14th. So if
anyone on the list was planning to attend and had not yet made their
reservations, I beg your indulgence and understanding. I'll encourage
you to get signed up before the 14th and we just might pull this
one off after all!
See: http://aeroelectric.com/seminars/ApexNC.html
Thanks!
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | "Optimum" antenna coax length for GPS? |
Comments/Questions: Bob, I have a Falco (all wood) with a Northstar M600
GPS, using RG-58 cable. I am replacing it with a Northstar M3 IFR GPS. The
M600 installation manual specifies the shortest possible antenna link
should be used.
The M3 manual says that RG-58 cable has a 23 dB loss per 100 ft @ 1500MHz
and the cable should be at least 10 ft and no longer than 50 ft. I am
planning on using RG-400 cable.
What is the dB cable loss per 100 ft for the RG-400, and based on the
RG-58 recomendation of at least 10 ft, what would you recommend as the
optimum cable length. The antenna is located on the glare shield so the
actual distance is pretty short - Appx 4 ft.
FYI, the folks at CMC told me that the cable would be "impotent" if too
short! The dictionary says impotent is "lacking in power, strength, or
vigor", so I definitely do not want an impotent antenna cable.
I cannot imagine where these guys are coming from. There's no
basis in physics where I can deduce the need for an "opitimum"
cable length. There ARE some GPS applications where multiple
antennas are use for ATTITUDE sensing in vehicles. This case
requires cables to be MATCHED to each other in very tight
tolerances but here too, it's not so much a matter of 'optimum'
length as it is 'same' length.
The relative differences between 142/400 and 58 can be seen at:
http://www.aeroelectric.com/articles/coaxloss.pdf
For the very short run you cite, these differences are
insignificant with respect to loss.
I do recommend RG-142 or RG-400 . . . not so much for their
losses over the 4' run you anticipate but for their advanced
materials and fabrication.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> bar |
| Subject: | Re: Master/Starter Contactor connection |
bar
bar
>
>Mathew,
>I did the exact thing you did...built a one bar strap to connect the
>relay. When the RV plans show a 2 bar! Further checking into resistance
>and load carrying of the copper bar eased my mind. Yes - I will loose a
>tiny bit of voltage when cranking. But so will the terminal ends, the
>other starter wires, the contactor, etc. It won't crank long enough to
>heat the bar up. So I just left it.
Oh, now I think I understand the original question about one or two
piece straps. Van must show two thin straps in sandwich. If one were
attempting to get the same cross section of copper in the jumper strap
as, say 4AWG copper: 4AWG = .204" diam or 3.14 x 0.1 x 0.1 or .031 square
inches. So a 3/4" wide copper strap would need to be .031/.75 = 0.041"
thick.
The K&S Engineering hobby metals centers found in many hobby and
hardware stores offers a .75 x .064" brass strip (#247) at
http://www.ksmetals.com/HobbyMerchandisers/metal_center.asp#
This would be great stuff from which to fabricate your jumper
straps between accessories with boss-hogg terminals on them.
Bob . . .
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: Internally regulated alternator OVP protection |
>After all of this, the one simple fact remains:
>If the FET (or other transistor) switching the field fails in the normal
way those
>components fail (shorted) - - you will have an uncontrolled runaway
alternator.
>At this point, there is really not much more to be said about the issue.
The
>internally regulated automotive alternators have a known single point
failure
>mode that is unacceptable in normal aircraft design circles.
>If people crashed when alternators failed - - it would be unacceptable for
the
>automotive world, too.
>That is the distinction, and it makes all of the difference.
>Regards, George
Elegantly stated George, but I can't agree.
Chopping the alternator with a Kilovac relay is a pretty good plan. And
there are other solutions. We need to know more about what goes on inside
some of the internally regulated alternators that are out there. In the
meantime the solution using the White_Rodgers_Emerson_Stancor Type 70
contactor is probably not a good plan to isolate the internally regulated
alternator because it won't kill the arc (If you poke a hole in the
contactor top and fill it with oil--then it will work as planned). I have
some technical types looking at the Type 70--but it reminds me of
technological archeology. So far my sources say "no way", but can't seem to
get the bottom file drawer open to show me the old data....
I think the option of using an external regulator complicates the design and
introduces problems that many do not recognize. I'll bet I could find ten
failed-in-flight alternators from people on this list and not a single
internally regulated runaway. It's all those wires and connections and parts
that cause failures--not the field FETs or transistors.
I confess---the concept of single-point failure just seems to me---vague and
even illusory---the kind of safety pronunciamento a committee might make.
Sure, I see that the concept has merit, but I try not to examine it closely
because I am certain that I will find it bogus.
We tend to defend against monsters from our past. I put dual batteries and
dual alternators into that category. The contactor, switch and related
wiring is probably less reliable than one good battery and one good
alternator bolted tight. And two of something tends not get get
inspected....because we have a backup anyway.
Bob was right that a press-to-test-switch is unnecessary with LEDs. Lots of
things are just like that and they are hard to see.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
"The man who carries a cat by the tail
learns something that can be learned
in no other way."
--Mark Twain
________________________________________________________________________________
| Subject: | Re: Internally regulated alternator OVP protection |
| From: | "George Braly" <gwbraly(at)gami.com> |
Eric,
I didn't say there were other add-on "fixes" that could be devised to avoid the
damage to the aircraft from the single point failure mode that is inherent in
the automotive internal regulator.
But that is the point. You are having to create a "work around" for a problem
that should not require a "work around".
And the work around still leaves the alternator vulnerable to a very high voltage
long term (minutes to hours depending on how long it takes to get the engine
shut down) melt down - - assuming the Kilovac disconnect works gracefully and
as absolutely it is intended to work.
Regards, George
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Eric M. Jones
Subject: AeroElectric-List: Re: Internally regulated alternator OVP protection
>After all of this, the one simple fact remains:
>If the FET (or other transistor) switching the field fails in the normal
way those
>components fail (shorted) - - you will have an uncontrolled runaway
alternator.
>At this point, there is really not much more to be said about the issue.
The
>internally regulated automotive alternators have a known single point
failure
>mode that is unacceptable in normal aircraft design circles.
>If people crashed when alternators failed - - it would be unacceptable for
the
>automotive world, too.
>That is the distinction, and it makes all of the difference.
>Regards, George
Elegantly stated George, but I can't agree.
Chopping the alternator with a Kilovac relay is a pretty good plan. And
there are other solutions. We need to know more about what goes on inside
some of the internally regulated alternators that are out there. In the
meantime the solution using the White_Rodgers_Emerson_Stancor Type 70
contactor is probably not a good plan to isolate the internally regulated
alternator because it won't kill the arc (If you poke a hole in the
contactor top and fill it with oil--then it will work as planned). I have
some technical types looking at the Type 70--but it reminds me of
technological archeology. So far my sources say "no way", but can't seem to
get the bottom file drawer open to show me the old data....
I think the option of using an external regulator complicates the design and
introduces problems that many do not recognize. I'll bet I could find ten
failed-in-flight alternators from people on this list and not a single
internally regulated runaway. It's all those wires and connections and parts
that cause failures--not the field FETs or transistors.
I confess---the concept of single-point failure just seems to me---vague and
even illusory---the kind of safety pronunciamento a committee might make.
Sure, I see that the concept has merit, but I try not to examine it closely
because I am certain that I will find it bogus.
We tend to defend against monsters from our past. I put dual batteries and
dual alternators into that category. The contactor, switch and related
wiring is probably less reliable than one good battery and one good
alternator bolted tight. And two of something tends not get get
inspected....because we have a backup anyway.
Bob was right that a press-to-test-switch is unnecessary with LEDs. Lots of
things are just like that and they are hard to see.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
"The man who carries a cat by the tail
learns something that can be learned
in no other way."
--Mark Twain
---
---
________________________________________________________________________________
| From: | rd2(at)evenlink.com |
| Subject: | off-topic - thick cessna windshield |
Sorry, off-topic, couldn't resist asking the list:
Does anyone know of a source for 0.25" thick windshield for a C-172 made 1981?
Or a heated one .25" ? (to make it somewhat more on topic :)
(The OEM product is 1/2 that and there is only one STC for .25" for C-172 I
know of, but for a different year.)
Rumen
________________________________________________________________________________
| From: | "Bob Barrow" <bobbarrow10(at)hotmail.com> |
| Subject: | SD-8 and No Battery |
The SD-8 will not boot unless power is available to it. Once running alone,
and the battery is removed from the bus, the likely scenario is that as long
as the loads are fairly constant, and within the output level of the SD-8,
it will continue to run. If the load is light, the bus voltage will rise,
possibly to near 15.0 volts. There will likely be noise in the audio.
Lastly, if a load such as a motor or incandescent load is switched on, the
momentary in-rush current will possibly "swamp" the alternator and all
output would be lost unless a battery restart is possible.
Therefore one might conclude that it is theoretically possible to run the
SD-8 without a battery (but not start it) but in reality it is not a safe or
practical concept.
I think this means that if you have a dual alternator (with the back-up
being the SD-8) and one battery system then the whole system relies on the
one battery not failing or becoming disconnected.
>Just to clear up my mind.... Will the SD-8 installed as per Bob's
>recommendations function acceptably in the event that it is disconnected
>from the battery?
>Is the battery needed to get the SD-8 "started"?
>Richard
Buy what you really want - sell what you don't on eBay:
http://adfarm.mediaplex.com/ad/ck/705-10129-5668-323?ID=2
________________________________________________________________________________
| From: | Speedy11(at)aol.com |
| Subject: | Re: Warning light press-to-test circuitry |
Bob N,
A valid and well-versed point.
The next question is: What are some functions the PTT could check and how do
I design and wire said contraption?
Stan Sutterfield
In a message dated 5/1/2005 2:57:58 AM Eastern Standard Time,
aeroelectric-list-digest(at)matronics.com writes:
When I design important electro-whizzies, there's a
test input pin that can be exercised with a push-button
on the panel. I use this input as a command to do
as much INTERNAL VERIFICATION OF FUNCTIONALITY as
possible. Hitting the PTT button and getting some
predictable behavior from the annunciator has much
a great deal more meaning and assurance of system
integrity.
In the mean time, very long lived LEDs have replaced
the limited life lamps for annunciation and indication.
But the PTT button for testing lamps seems to have
persisted. I'll suggest that unless a proposed PTT
system does more than illuminate LEDs, that adding
the PTT system reduces reliability (lots of extra
wiring, diodes, etc), increases $time$ to fabricate
and install the system and ultimately tells you
nothing of interest when you push the button.
________________________________________________________________________________
| From: | "J. Mcculley" <mcculleyja(at)starpower.net> |
| Subject: | Re: SD-8 and No Battery |
I have been operating with the SD-8 and a single battery setup with a
33,000 microfadad capacitor across the buss to act as a short duration
"battery" in the event of temporary or permanent loss of the battery
connection to the buss. Testing via both short and long term operation
with the battery master turned off has shown that the SD-8 continues to
carry the buss load without interruption. I have never seen the voltage
exceed 14.2 volts. The capacitor may also provide some noise filtering
function although I have never been troubled by a need for noise
abatement, so can not attest to that capability.
Jim McCulley
Bob Barrow wrote:
>
> The SD-8 will not boot unless power is available to it. Once running alone,
> and the battery is removed from the bus, the likely scenario is that as long
> as the loads are fairly constant, and within the output level of the SD-8,
> it will continue to run. If the load is light, the bus voltage will rise,
> possibly to near 15.0 volts. There will likely be noise in the audio.
> Lastly, if a load such as a motor or incandescent load is switched on, the
> momentary in-rush current will possibly "swamp" the alternator and all
> output would be lost unless a battery restart is possible.
>
> Therefore one might conclude that it is theoretically possible to run the
> SD-8 without a battery (but not start it) but in reality it is not a safe or
> practical concept.
>
> I think this means that if you have a dual alternator (with the back-up
> being the SD-8) and one battery system then the whole system relies on the
> one battery not failing or becoming disconnected.
>
>
>
>>Just to clear up my mind.... Will the SD-8 installed as per Bob's
>>recommendations function acceptably in the event that it is disconnected
>
>>from the battery?
>
>
>>Is the battery needed to get the SD-8 "started"?
>
>
>>Richard
>
>
> Buy what you really want - sell what you don't on eBay:
> http://adfarm.mediaplex.com/ad/ck/705-10129-5668-323?ID=2
>
>
>
>
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: SD-8 and No Battery |
>
>
>I have been operating with the SD-8 and a single battery setup with a
>33,000 microfadad capacitor across the buss to act as a short duration
>"battery" in the event of temporary or permanent loss of the battery
>connection to the buss. Testing via both short and long term operation
>with the battery master turned off has shown that the SD-8 continues to
>carry the buss load without interruption. I have never seen the voltage
>exceed 14.2 volts. The capacitor may also provide some noise filtering
>function although I have never been troubled by a need for noise
>abatement, so can not attest to that capability.
>
>Jim McCulley
Excellent DATA Jim, thanks for sharing.
Folks, Jim has described an experiment wherein he deduced
some things about the performance of the SD8 alternator. This
is exactly the kind of information that invites others to REPEAT the
experiment. There is no more solid foundation for the development and
sharing of what works than to have two or MORE independent investigators
try something, get similar or identical results and then share those
results with others.
Remember how our math teachers asked us to "show the work"?
It's not sufficient to simply "know" and pass along an answer
without details on the supporting, repeatable experiment. More
than once I recall getting the same answer as another student only to
be shown where we both made the same mistake in its production.
A whole lot of stuff cited as gospel is based on papers by writers
with airs of authority. Then there are experiments that are poorly
crafted, conducted with bias and/or mis-interpreted that are never
repeated yet accepted as valid. Finally, there's the ol' mechanic
and pilot's tales based mostly on hearsay and embellished with
imagination in every telling.
Interestingly enough, this is the very tool that empowers
those who DO NOT experiment to evaluate things they read
or are advised to do. You don't have to be conversant in the
technology or science of the topic to ask, "Who were the
experimenters? How did their results compare? What are
the simple ideas that underpin the conclusions?" Obviously,
you're not going to get a real data-dump on every juicy
tid-bit passed on to you during the course of building
and owning your airplane. But lacking such information, you
are perfectly reasonable to be skeptical of everything
that is not so supported . . . and perhaps resolve to
do your own experiment to confirm or debunk the accuracy
of what you are told.
When in doubt, post it here on the List where numbers
of folks can peek under all the rocks, consider the unasked
questions and help you make sense of the of the
imponderable.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: SD-8 and No Battery |
>
>
>The SD-8 will not boot unless power is available to it. Once running alone,
>and the battery is removed from the bus, the likely scenario is that as long
>as the loads are fairly constant, and within the output level of the SD-8,
>it will continue to run. If the load is light, the bus voltage will rise,
>possibly to near 15.0 volts. There will likely be noise in the audio.
>Lastly, if a load such as a motor or incandescent load is switched on, the
>momentary in-rush current will possibly "swamp" the alternator and all
>output would be lost unless a battery restart is possible.
>
>Therefore one might conclude that it is theoretically possible to run the
>SD-8 without a battery (but not start it) but in reality it is not a safe or
>practical concept.
>
>I think this means that if you have a dual alternator (with the back-up
>being the SD-8) and one battery system then the whole system relies on the
>one battery not failing or becoming disconnected.
Another good data dump with well considered comments.
Thank you sir!
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> circuitry |
| Subject: | Re: Warning light press-to-test |
circuitry
circuitry
>
>Bob N,
>A valid and well-versed point.
>The next question is: What are some functions the PTT could check and how do
>I design and wire said contraption?
>Stan Sutterfield
I presume you're asking about how to add MEANINGFUL press-to-test
capability to an LED based annunciation system.
The very BEST way is to exercise everything that gets annunciated
during pre-flight and NOT have a press-to-test system. Of hand,
I can't think of any commonly annunciated conditions that cannot
be confirmed by exercising that feature.
For example, low volts and low pressure lights should be on
with the engine stopped and go out at appropriate times as
the engine spools up and alternators are brought on line.
Canopy latches can be cycled, etc.
Make a list of all the lights you plan to have and then
post the ones that you can't cycle. Let's study the sensors
and wiring associated with that function and see if there
are ways to craft a meaningful pre-flight activity to confirm
operation of the system. This applies to aural warnings as
well.
The ideal system has NO press-to-test buttons that do not
exercise the whole warning system.
Bob . . .
________________________________________________________________________________
| From: | Richard Riley <Richard(at)RILEY.NET> |
| Subject: | Re: SD-8 and No Battery |
At 12:33 AM 5/1/05, Bob Barrow wrote:
>
>
>The SD-8 will not boot unless power is available to it.
Why not? Isn't it a permanent magnet dynamo?
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: SD-8 and No Battery |
>
>At 12:33 AM 5/1/05, Bob Barrow wrote:
> >
> >
> >The SD-8 will not boot unless power is available to it.
>
>Why not? Isn't it a permanent magnet dynamo?
It's the way the regulator is designed. Your question
is well grounded . . . if AC power is available any time
the alternator is turning, why should it take external
bias to wake up the regulator?
Good thing to hit up B&C about. I wouldn't design the
regulator that way . . . and perhaps the supplier of
their present regulator would be amenable to adding
the hand full of components necessary to make the
system come up by itself.
Bob . . .
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
| Subject: | Just an Expensive Hobby?!?!?! |
0.37 PLING_QUERY Subject has exclamation mark and question mark
0.00 MANY_EXCLAMATIONS Subject has many exclamations
AeroElectric-List message previously posted by: "Robert L. Nuckolls, III"
<<........skip.......This IS after all, just an expensive
hobby......skip......Bob>>
5/1/205
Now, in addition to the pornography filter on my computer, I will have to
add a heresy filter so that my wife is not exposed to such damning words!!
OC
________________________________________________________________________________
| Subject: | Re: SD-8 and No Battery |
Richard Riley a crit :
>
>At 12:33 AM 5/1/05, Bob Barrow wrote:
>
>
>>
>>
>>The SD-8 will not boot unless power is available to it.
>>
>>
>
>Why not? Isn't it a permanent magnet dynamo?
>
>
>
>
I believe it all depends on the regulator.
Last year we conducted some experimenets with a Rotax 912 PM alternator
and two regulators : the standard Rotax-Ducati unit and a replacement
unit, the Schicke GR 4.
With no battery on-line, the Ducati doesn't come to life whereas the
Schicke boots with no problem.
I think this is an explanation for the 22000 uF capacitor included by
Rotax in it's circuit.
FWIW,
Regards,
Gilles Thesee
Grenoble, France
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Just an Expensive Hobby?!?!?! |
>
>
>AeroElectric-List message previously posted by: "Robert L. Nuckolls, III"
>
>
> <<........skip.......This IS after all, just an expensive
>hobby......skip......Bob>>
>
>5/1/205
>
>Now, in addition to the pornography filter on my computer, I will have to
>add a heresy filter so that my wife is not exposed to such damning words!!
Do you mean you've been able to convince her that it was
anything else? Hmmmm . . . I did hear a comment from a wife
at OSH a number of years ago wherein she expressed thankfulness
for her husband's airplane project. She didn't elaborate as
to what his alternative activities might be. The
not-so-obvious possibilities are indeed endless. I guess I'll
have to categorize that statement as not belonging to the set
of simple-ideas pertaining to the OBAM aviation community.
I humbly stand corrected.
The simple idea of 'hobby' is not universally applicable . . .
but I think 'expensive' still is.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: SD-8 and No Battery |
>
>I believe it all depends on the regulator.
>Last year we conducted some experimenets with a Rotax 912 PM alternator
>and two regulators : the standard Rotax-Ducati unit and a replacement
>unit, the Schicke GR 4.
>
>With no battery on-line, the Ducati doesn't come to life whereas the
>Schicke boots with no problem.
>
>I think this is an explanation for the 22000 uF capacitor included by
>Rotax in it's circuit.
A fat capacitor is ALWAYS indicated for smoothing the output
of a PM alternator system. They are by design, very noisy compared
to the wound-field, three-phase alternators.
I was mystified by the discovery that many of the series-pass,
phase-triggered SCR regulators wouldn't self start. Of course,
it's relatively easy to assume that every system will have a battery.
It takes a couple of diodes, a capacitor and a resistor to get
these extra simple regulators to come up by themselves irrespective
of the presence of a filter capacitor.
Bob . . .
________________________________________________________________________________
| From: | "Dick Fisher" <sonex76(at)velocity.net> |
| Subject: | Figure Z-20 Small Jabiru System |
Hi Bob,
On the Z-20 drawing you show a "starter contactor". Is this a continuous duty solenoid
or intermittent duty? I had already mounted both devices on my firewall before
I had
received your drawing and also included the 5A circuit breaker in my panel.
How do I go about wiring the continuous duty solenoid to the
2-10 switch and fuse panel ?
Your assistance is greatly appreciated.
Dick Fisher
sonex76(at)velocity.net
________________________________________________________________________________
| Subject: | Re: SD-8 and No Battery |
| From: | James H Nelson <rv9jim(at)juno.com> |
Hi Bob,
I would like the "8" to be available when my alternator goes
south either by electrons going astray or throwing a drive belt. This
SD-8 unit would be the best back up for simplicity and dependability. I
am planing for two "P" mags and the SD-8 as my back up. Its enough to
run my EFIS and com. The battery won't die this way so every thing else
will be available upon landing by getting their energy from the fully
charged battery.
Jim Nelson
RV9-A (N599RV-reserved)
________________________________________________________________________________
| From: | <gmcjetpilot(at)yahoo.com> |
| Subject: | Re: Internally regulated alternator OVP protection |
Dear: Eric, George B., Bob N., Steve and Ken,
The thought of flying for an hour with an OV is not plausible, at least if you
just reach up and turn the master switch off or pull the b-lead circuit breaker
(if you have one). That will be my procedure if the OV light comes on. The alternators
internal fuse (if you have one) will fail within 1-30 seconds depending
on the severity of the OV.
The word fire scares people. Protection from electrical fires is critical. I researched
the web and found electrical fires in cars do occur, mostly in wiring
not alternators. How rare is it?
ND alternators, favored by homebuilders are found in automobiles such as: Toyota
Tercel, Suzuki Swift/Samurai, Geo Metro and Chevy Sprint, to name a few. Checking
for complaints, safety bulletins or recalls against these cars in the NHTSA-
National Highway Traffic Safety Administration database going back to 1972,
showed no alternator fires. However it is interesting other car models catch
fire with alarming frequency. Some Ford alternators and Hitachi alternators
in some Nissans apparently have a history of catching things on fire, in part
to both alternator design and installation (wiring) issues.
Alternators do catch fire, in one case. A boat fire from an alternator was due
to a failed bearing that blew grease out, catching fire. It was not a ND and it
had an External-VR. To support a fire you need heat, O2 and fuel, so I think
the fire danger to us is very remote if the alternator is not near anything combustible.
Painting All I-VR with a broad brush is not adequate to describe a wide range of
designs. What burned up on your bench years ago may not be a valid comparison
to designs today. Also if you have one potential failure point, you add enough
protection & safe guards so the risk becomes acceptable. Of course as cockpits
become more "glass" the stakes go up.
I would suggest if motivated by protection of expensive avionics, consider protecting
just the avionics buss with an OV module/relay (preferably solid state).
A back-up battery powers the avionics/ignition when the (delicate) avionics
buss ISOLATES after an over voltage trip. The advantage is you are switching 10
amps, not 100 amps. Since this buss is continuously powered by the back-up battery
and main battery, you will never loose power to the radios. When the alternator
shuts down (internal OV protection or fuse) or you manually pull the
b-lead CB, you could re-connect the main battery back to the avionics buss. Bob
N. does not recommend a big-old circuit breaker for the B-lead on your panel
to reduce potential electrical noise.
I dont think anyone said OV in an I-VR cant happen, but it is rare. The designers
know this. That is why they have secondary protection with current fuses. Do
all alternators use this? Dont know. The ND model I have has a current fuse
(short circuit) protection in the field circuit. Current fuses are very common
in power equipment. They are thermal devices so they tend to be de-rated to avoid
blowing too early. The good part is they will blow and protect the alternator
wires from melt down; the bad part is they will not blow fast enough to protect
electronics. The time to blow is based on % over rated capacity. They blow
in less than 1 second to a max of 30 seconds per specs (not an hour). The
good part is they will fail before the alternators wires, solder connections and
rectifier can melt and get too hot or produce sparks. That is the idea anyway.
I know stories state otherwise, but without knowing what alternator it occurred
to, how, what and why, the info is a questio
n mark.
I stated the 0.5 million hours MTBF (statistical) number for I-VR failures is based
on running electronics near their thermal limit. So the typical alternator
VR will go 57 year without failing an electronic component. If an airplane environment
is 100 times more severe than this, you could still expect 5,000 hours
without failure. Your wing spar may be a single (point) load path part. It
is trusted because of safety factors incorporated. We dont add another wing as
a back up. This is the same with alternators; make is so reliable that a failure
is unlikely. Wings come off and alternators fail, but at least an alternator,
even after an over voltage, should still allow you to land safely on battery
power. The issue of burning fancy avionics is still there.
Most of the discussion has been around the transistor, but according to the engineers,
in a power system with a transistor, diode and IC, the IC is most likely
to fail sooner. I doubt the IC alone will cause an OV and probably fault tolerant,
like your cars computer, with a limp home mode. IC logic can protect the
alternator way better than old VRs, which only had basic VR functions. Clearly
the modern I-VR has a lot more going for it than just regulation of the juice,
such as over voltage protection. How effective it is I dont know, but because
there are so few, if any, confirmed OV cases with them (ND), I guess it works
well.
Past history of old VR technology, internal or external, is like the stock market,
past performance is no indication of future performance. My original premise
was millions are in the field with no problems. Albeit cars and industrial
equipment are not planes, there are ND and Mitsubishi alternators flying for over
8 years or more in planes. That speaks for itself. If you must put extra
OV protection on an I-VR, consider just protection of the delicate avionics buss,
as suggested above.
The whole point to my discourse is what really is going on in an I-VR, preferably
facts and tests for a particular model of alternator?
Thanks George RV-7
________________________________________________________________________________
| From: | Richard Riley <Richard(at)RILEY.NET> |
| Subject: | Re: SD-8 and No Battery |
At 10:06 AM 5/1/05, Robert L. Nuckolls, III wrote:
> Good thing to hit up B&C about. I wouldn't design the
> regulator that way . . . and perhaps the supplier of
> their present regulator would be amenable to adding
> the hand full of components necessary to make the
> system come up by itself.
Damn. I'd settled on an SD8 as a backup. I wanted to be able to run on
any one of the three electrical sources, now suddenly I'm back down to 2.
________________________________________________________________________________
| From: | "Bob Barrow" <bobbarrow10(at)hotmail.com> |
| Subject: | Re: SD-8 and No Battery |
Yes the SD-8 is a Permanent Magnet alternator. However the regulator is
"downstream" of the bridge rectifier in the regulator box. The regulator
circuitry turns on the gates of the bridge rectifier to get energy from the
alternator for the bus. If there is no "battery" attached to the output
first, then the regulator is unable to fire the gates. Once the rectifier is
running, the regulator will get its energy from the bridge output. But if a
momentary load added to the system pulls the bus below a value that allows
the regulator to function.....then the gates will not fire and the output
will collapse. As long as you have only one battery there seems to be a
potential for total power loss.
Now the question should be asked. Why is the PMag from emagair any
different. Will it run permanently in total isolation from the battery and
the rest of the electrical system. And if it can operate as a truly self
contained auxiliary power source .....why cannot the SD-8 be designed to
perform similarly.
>From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
>Reply-To: aeroelectric-list(at)matronics.com
>To: aeroelectric-list(at)matronics.com
>Subject: Re: AeroElectric-List: SD-8 and No Battery
>Date: Sun, 01 May 2005 12:06:27 -0500
>
>
>
>
>
> >
> >At 12:33 AM 5/1/05, Bob Barrow wrote:
> > >
> > >
> > >The SD-8 will not boot unless power is available to it.
> >
> >Why not? Isn't it a permanent magnet dynamo?
>
> It's the way the regulator is designed. Your question
> is well grounded . . . if AC power is available any time
> the alternator is turning, why should it take external
> bias to wake up the regulator?
>
> Good thing to hit up B&C about. I wouldn't design the
> regulator that way . . . and perhaps the supplier of
> their present regulator would be amenable to adding
> the hand full of components necessary to make the
> system come up by itself.
>
> Bob . . .
>
>
REALESTATE: biggest buy/rent/share listings
http://ninemsn.realestate.com.au
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Small pidg terminals |
>
>I'm working on upgrading and intercom and a couple of instruments. The
>avionics were set up to use a terminal strip and the old intercom harness
>had some small PIDG terminals specified for 26-22 AWG, yellow color. I've
>found a source for these terminals, but was wondering about a crimper. The
>"good and cheap" crimpers all seem to have the three red,blue,yellow
>postions, but nothing for the small yellow terminals.
>
>Am I stuck buying one of the expensive crimpers? Should I just go ahead
>and use the red 22-18 AWG terminals? The wire is 22 AWG.
The red terminals are slightly larger at the wire barrel but
if they fit into your available space, they'll be fine too.
Bob . . .
________________________________________________________________________________
| Subject: | Starter contactor? |
| From: | "Tim Dawson-Townsend" <Tdawson(at)avidyne.com> |
Bob:
I sent this to through your website, but thought I should post it here.
We're building an RV-10 and generally following your Z-14 diagram. The
idea I had I wanted to run by you was to wire the starter contactor directly
to the battery, instead of through the battery contactor.
Advantages:
1)less connections for loss between batt and starter;
2) battery contactor can
be smaller since it doesn't have to handle starting loads.
Disadvantages:
no way to turn off a stuck starter contactor.
I've got a real nice starter contactor, so maybe that helps against that concern.
We have a 24 volt system in the plane and good contactors have been hard to
track down. What do you think?
Thanks, Tim D-T
P.S. Our battery is in the back of the plane . . .
**********************************
Tim Dawson-Townsend
Systems Engineer
Avidyne Corporation
781-402-7418
tim(at)avidyne.com
**********************************
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: SD-8 and No Battery |
>
>At 10:06 AM 5/1/05, Robert L. Nuckolls, III wrote:
> > Good thing to hit up B&C about. I wouldn't design the
> > regulator that way . . . and perhaps the supplier of
> > their present regulator would be amenable to adding
> > the hand full of components necessary to make the
> > system come up by itself.
>
>Damn. I'd settled on an SD8 as a backup. I wanted to be able to run on
>any one of the three electrical sources, now suddenly I'm back down to 2.
How so? Most main alternators need a battery to come on line
too . . . There seems to be an increasing number of machines
that will come up self excited but they're rare and probably
not DESIGNED for that characteristic.
Example: I was tasked with designing a regulator for Bonanzas
way back when. The spec from Beech required that I be able
to take advantage of the alternator's self-excitation
capabilities. Okay, went out to Beech and borrowed an alternator.
On the drive stand, the residual output from the b-lead with
the field disconnected was about 1.5 volts. Hmmmm, not enough
to get the regulator electronics to come alive . . . we were
working in a 28v system. I had to redesign the regulator
so that it would offer a bit of leakage through the powered-
down device.
Sure enough, the smallest amount of feedback from b-lead to
field would cause the system to wake up and run regulated.
Now, having accomplished the assigned task, I did NOT go
investigate the alternator's performance with respect to
bus voltage quality sans battery.
In later years . . . many later years, I heard of a fuss
about a batch of alternators that were rejected because
they would not self-excite. This caused a great thrashing
through the specs, purchase contracts, acceptance test
procedures, etc. The supplier was called on the carpet
and was feeling really beat up . . . "Look, there's
no requirement for this alternator to self excite."
Sho'nuf. Nobody could point to any controlling document
and cite a requirement for self-excitation. The vast
majority of alternators would do it . . . so many in
fact that Beech ASSUMED that it was a designed in feature
and decided to capitalize on it.
But when some process change or stack up of production
variables generated a batch of alternators that would
not self-excite, folks started shoveling garbage into
the fans. In fact, the supplier had never intended
that the alternator perform in this manner and Beech
simply assumed that the characteristic was designed in.
I've often wondered how much it would affect the
normal operation of an alternator to simply add
a little rare-earth magnet pellet to the field
assembly to cause some tiny but fixed amount of
field flux to always exist. We know that there are
alternator field assemblies with sufficient magnetic
retention to bring themselves on line but I wonder
if this is a controlled, design-in feature or
a happy fallout of production variables.
So, given the current state of the art, you're
system has always depended on battery for 100%
assurance of start up. There have been words
written on the List alluding to battery failures
due to open cells. I have spoken with the
manufacturer about this phenomenon and he tells
me that nobody ever contacted him about this
problem nor were any batteries returned for
failure analysis. They have seen some single
cell failures but all were reported in large biz-jet
size batteries. All had been subject to poor
operating or maintenance practices.
It's kinda like all those builders who were
unhappy about the performance of the crowbar
ov modules who never called the manufacturer, never
asked for assistance in fixing problems, never
asked for their money back, and are not coming
out of hiding even when I've offered to return their
money no matter what.
The well maintained RG battery is about as reliable
a power source as you can get. Figure Z-13 bypasses
the battery contactor (a highly stressed part with
system wiring subject to damage and failure) so while
we can sit around and wring our hands about the
possibilities, the PROBABILITY of these things
happening in hazardous combinations is extremely
low.
Does anyone really expect a battery that cranked an
engine less than three hours ago is suddenly going to
decide to chuck a cell? Even if it does become unhooked,
you probably won't know it unless you perceive some
increase in noises . . . but again, the #1 rule is
don't troubleshoot in flight. If things are working
but noisier, leave the switches alone until you're
on the ground, passengers unloaded and THEN get out
the toolbox.
If you have a battery disconnect, everything will
probably continue to run until you DO something to
tip the system over the edge.
If you have an RG battery and modern, externally
regulated alternator with active notification of
low voltage and ov protection, you already have
system reliability a factor of 10x or better than
the stuff flying around in most spam cans. If you're
willing to rent a spam can, pile the kids and
dog into it for a trip, then I'll suggest that
all the concerns recently raised about POSSIBLE
failures are only emotionally expensive and are
not helping you add value to your airplane.
Keep this in mind too: YOUR AIRPLANE IS NOT
CARVED IN STONE. Unlike the utopian idea that
100.0% conformity makes for safer airplanes,
we all know that incorporation of new ideas
that reduce cost, improve performance and
reduce parts count are the things that really
contribute to safety. You're system is failure
tolerant such that new ideas can be comfortably
incorporated without spending $time$ to qualify
and certify the changes.
Decisions you make today about what goes into your
airplane can be changed tomorrow when it proves useful
to do so. If it were my airplane, Figure Z-13/8 with
a pair of p-mags is my own utopian idea of system
performance and reliability . . . TODAY. Can't tell
you about tomorrow. But for today, I know that what's
available stands very tall against the majority of
what's flying and it can only get better.
Let not your heart be troubled my friend. Concentrate
on getting your 40 hours flown off . . . if only with
the bare vfr/day spam can systems installed. There are some
nifty things coming over the hill but don't wait on them.
Get the FAA out of your hair and THEN concentrate on the
incremental improvements that will stake out your place in the
constellations of OBAM aircraft stardom.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: SD-8 and No Battery |
>
>
>Yes the SD-8 is a Permanent Magnet alternator. However the regulator is
>"downstream" of the bridge rectifier in the regulator box. The regulator
>circuitry turns on the gates of the bridge rectifier to get energy from the
>alternator for the bus. If there is no "battery" attached to the output
>first, then the regulator is unable to fire the gates. Once the rectifier is
>running, the regulator will get its energy from the bridge output. But if a
>momentary load added to the system pulls the bus below a value that allows
>the regulator to function.....then the gates will not fire and the output
>will collapse. As long as you have only one battery there seems to be a
>potential for total power loss.
Correct . . . but it will run fine no battery if there's sufficient
filter capacitor installed and the battery fails spontaneously . . .
just an hour or so after it successfully started an engine. Rather
than focusing on what the SD-8 will or will not do without a battery,
would it be better to resolve likelihood of battery failure under the
circumstances in which it is used?
>Now the question should be asked. Why is the PMag from emagair any
>different. Will it run permanently in total isolation from the battery and
>the rest of the electrical system. And if it can operate as a truly self
>contained auxiliary power source .....why cannot the SD-8 be designed to
>perform similarly.
It can.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: SD-8 and No Battery |
>
>Hi Bob,
> I would like the "8" to be available when my alternator goes
>south either by electrons going astray or throwing a drive belt. This
>SD-8 unit would be the best back up for simplicity and dependability. I
>am planing for two "P" mags and the SD-8 as my back up. Its enough to
>run my EFIS and com. The battery won't die this way so every thing else
>will be available upon landing by getting their energy from the fully
>charged battery.
I can deduce no errors of logic in your design goals and
assertions.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Figure Z-20 Small Jabiru System |
>
>Hi Bob,
>
>On the Z-20 drawing you show a "starter contactor". Is this a continuous
>duty solenoid
> or intermittent duty?
starter contactors are all intermittent duty devices.
> I had already mounted both devices on my firewall before I had
>received your drawing and also included the 5A circuit breaker in my panel.
>How do I go about wiring the continuous duty solenoid to the
>2-10 switch and fuse panel ?
Wire it like Z-16
Bob . . .
________________________________________________________________________________
| From: | "Sally and George" <aeronut58(at)hotmail.com> |
| Subject: | Regulator connections |
I have an alternator, voltage regulator and overvoltage relay from a Beech
19. The VR and OV relay are Lamar products.
The voltage regulator has three leads: a red, a yellow, and a black. The
black lead is connected to a black lead on the overvoltage relay, which has
three other leads coming out: a read, a green and a white.
Does anyone out there know how those leads should be connected?
George Kilishek
________________________________________________________________________________
| From: | Richard Riley <Richard(at)RILEY.NET> |
| Subject: | Re: SD-8 and No Battery |
At 07:25 AM 5/2/05, Robert L. Nuckolls, III wrote:
> So, given the current state of the art, you're
> system has always depended on battery for 100%
> assurance of start up...... The well maintained RG battery is
> about as reliable a power source as you can get. Figure Z-13 bypasses
> the battery contactor (a highly stressed part with
> system wiring subject to damage and failure) so while
> we can sit around and wring our hands about the
> possibilities, the PROBABILITY of these things
> happening in hazardous combinations is extremely
> low.
My irrational prejudice is that, from time to time and with little
provocation, batteries explode.
My family business is a self service car wash. For the last 35 years, a
couple of times a year, someone will wash their car, go to start it, and
the battery blows up. Usually it's just a chunk of the top blowing off,
once it was the bottom - which resulted in the battery launching itself at
high speed into the hood, leaving a 4" bulge.
It once happened to me, with a 69 Firebird convertible, in about 1988. No
great damage, but a loud bang followed by dripping acid.
I know that, as you say, it NEVER happens. But I've seen it and
experienced it. So I assume (there's that word again) that it will happen
again, to me, at the worst possible moment.
So I've been planning for an all electric airplane - including electronic
ignitions - that could re-boot in case the battery explodes in IFR
conditions. I have a vented kevlar battery box for a 25 AH sealed lead
acid battery, SD-8 and L60 alternators, LR3 regulator. I have a backup
lithium primary cell just for one electronic ignition, it should give me
3-5 hours of ignition time if everything else is off line.
I figured if the battery exploded and went to dead short, I could take it
off line, bring up the SD-8, and use that to excite the LR60. The gyros
have their own short term backup batteries. I'm aiming not only to
mitigate risk, but to allow a graceful recovery.
That the SD-8 cannot self excite is a disappointment, almost from an
aesthetic point of view. Certainly, given the number of small backup
batteries I already have, I can go to a 2 battery 2 alternator layout, or
use the lithium ignition backup to excite the SD-8. I always though the
reason you use permanent magnets in an alternator is that it IS self
exciting that way. When a piece of equipment has an inherent functionality
designed out of it, I'm offended as a consumer. It's like having to buy
the crippled electronic widget because the full function one is scheduled
for the next release, in 18 months, but it's available in Japan for half
the price today.
I want the people that I buy from to do the very best job they can,
especially since my life, and maybe my children's, are on the
line. Working to make their products LESS capable is just distasteful.
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: SD-8 and No Battery |
>My irrational prejudice is that, from time to time and with little
>provocation, batteries explode.
It takes a LOT of provocation . . .
>My family business is a self service car wash. For the last 35 years, a
>couple of times a year, someone will wash their car, go to start it, and
>the battery blows up. Usually it's just a chunk of the top blowing off,
>once it was the bottom - which resulted in the battery launching itself at
>high speed into the hood, leaving a 4" bulge.
>
>It once happened to me, with a 69 Firebird convertible, in about 1988. No
>great damage, but a loud bang followed by dripping acid.
>
>I know that, as you say, it NEVER happens. But I've seen it and
>experienced it. So I assume (there's that word again) that it will happen
>again, to me, at the worst possible moment.
It has happened . . . many times with flooded batteries that
gas a lot and have a lot of volume above the fluid level combined
with some failure within the battery's crossover connectors
to ignite the gasses.
It's even happened in an RG battery in a bizjet . . . but it
took a specific series of events to pull it off. First, the
battery was accidently subjected to a heavy discharge . . . sufficient
to partially melt the crossovers between cells. The battery was
improperly re-charged and stuck back into the airplane. When
an engine start was attempted, an already damaged crossover
opened and ignited gasses in the headspace. Noisy. Blew the
top off the battery. Started a BIG investigation into root cause
and much threats of lawsuit. Bottom line was that the lid
blew off and no damage was done to the airplane. The battery
was replaced on warranty in spite of the fact that the customer
did it to himself.
Crossovers were redesigned to withstand continuous dead short
of a new battery so that only the battery gets hot, out-gasses
and poofs the overpressure vents. This test has been repeated
many times at the Naval Battery Research Laboratories at
Crane, Indiana. Many RG batteries have been studied, beat up,
bashed, baked, kicked and electrically abused in every way
they could devise . . . the critters hang together well.
Has Crane tested the Panasonic LC1218? Don't know.
>So I've been planning for an all electric airplane - including electronic
>ignitions - that could re-boot in case the battery explodes in IFR
>conditions. I have a vented kevlar battery box for a 25 AH sealed lead
>acid battery, SD-8 and L60 alternators, LR3 regulator. I have a backup
>lithium primary cell just for one electronic ignition, it should give me
>3-5 hours of ignition time if everything else is off line.
>
>I figured if the battery exploded and went to dead short, I could take it
>off line, bring up the SD-8, and use that to excite the LR60. The gyros
>have their own short term backup batteries. I'm aiming not only to
>mitigate risk, but to allow a graceful recovery.
Gee . . . your worry bucket is really full. But keep in mind
that every catastrophic event is a stack-up of precursors.
Unless you plan to abuse your battery in the proper combination
of actions to set up the event . . . only then will you conduct
your own test as to how well their cross-overs hang together . . .
and this isn't going to happen in flight.
Oh yeah, don't put your battery in a battery box. A Glasair
suffered an event about 15 years ago where the alternator went
into OV, no OV protection was present, battery out-gassed,
pilot went to the in-flight, troubleshooting mode and started
flipping switches. Battery contactor INSIDE the battery box set
of the gasses and blew up the battery box . . . not the battery.
Again, a long list of precursors . . . but let your battery sit out in
the breeze.
>That the SD-8 cannot self excite is a disappointment, almost from an
>aesthetic point of view. Certainly, given the number of small backup
>batteries I already have, I can go to a 2 battery 2 alternator layout, or
>use the lithium ignition backup to excite the SD-8. I always though the
>reason you use permanent magnets in an alternator is that it IS self
>exciting that way. When a piece of equipment has an inherent functionality
>designed out of it, I'm offended as a consumer.
It wasn't DESIGNED out . . . the SD-8 regulator is a purchased
part that met the design goals of the time and many hundreds
are flying. To my knowledge, nobody has sent any back because
they thought they were being offered anything different than
what they purchased.
>It's like having to buy
>the crippled electronic widget because the full function one is scheduled
>for the next release, in 18 months, but it's available in Japan for half
>the price today.
You're alluding to facts not in evidence and assuming
that B&C made some considered and intentional effort
to short-change anyone. The limitations on the SD-8 have
been discussed here on the list many times but this is
the first time I recall anyone finding that the product
didn't meet a prime requirement.
>I want the people that I buy from to do the very best job they can,
>especially since my life, and maybe my children's, are on the
>line.
Unless the market makes their wishes known, the supplier
is flying blind. Most folks worry-buckets do not include
catastrophic loss of a well maintained, un-abused RG
battery. It's good that you're now aware of the limitations.
Perhaps you can identify a regulator to go with the SD-8 that
is not so limited. They're pretty generic devices. A PM alternator
the fits the vacuum pump pad is the hard part.
> Working to make their products LESS capable is just distasteful.
Who is WORKING to make their products less capable? Capability
is a function of design goals that are a compromise between
over-design and offering a product that the marketplace
will find attractive enough to support. It's always a gamble.
Had we designed the LR series regulators in three parts and
offered each part for $75 would we have sold more total product?
Who knows? The LR series regulators are what they are. If
you don't find them attractive, you're free and expected
to find products that you like. Same for the SD-8 and its
regulator of limited capability.
You're encouraged to seek whatever configuration gives you
comfort. But please don't bash B&C or anyone else for not
meeting requirements you've never asked them to meet
and then infer that they made considered decision to short-
change you or anyone else.
Bob . . .
________________________________________________________________________________
| From: | N1deltawhiskey(at)aol.com |
| Subject: | Re: Small pidg terminals |
If I interpret Ken's question correctly, he has some terminals with a smaller
barrel than the usual red sleeved terminals for 20-24 wire. I have some of
these as well (1/8" wide I believe for use on microswitches) and the issue I
found was that the red position on the B&C crimper would not clamp sufficiently
to prevent the #22 wire from being pulled out under load. I had to apply an
additional tighter crimp with pliars that would close more tightly to get a
connection that I could not pull apart.
Regards, Doug Windhorn
In a message dated 02-May-05 6:28:34 Pacific Standard Time,
b.nuckolls(at)cox.net writes:
>
>I'm working on upgrading and intercom and a couple of instruments. The
>avionics were set up to use a terminal strip and the old intercom harness
>had some small PIDG terminals specified for 26-22 AWG, yellow color. I've
>found a source for these terminals, but was wondering about a crimper. The
>"good and cheap" crimpers all seem to have the three red,blue,yellow
>postions, but nothing for the small yellow terminals.
>
>Am I stuck buying one of the expensive crimpers? Should I just go ahead
>and use the red 22-18 AWG terminals? The wire is 22 AWG.
The red terminals are slightly larger at the wire barrel but
if they fit into your available space, they'll be fine too.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Some news on the CBA-II battery tester. |
I've been exercising the CBA-II pretty much 24/7 since
the smoked one got replaced. I bought some el-cheeso, house
brand alkaline cells a couple of days ago on sale for .25
per cell. I ran a couple through the CBA-II and followed up
with a new "Bunny Battery" . . . the results of these three
tests are shown at:
http://www.aeroelectric.com/Pictures/El-Cheeso_Battery_Test.jpg
I've noted what I think is a "bug" in the software that randomly
drops a single reading (See red and green traces that go to zero
in the middle of the test?). Haven't observed this on anything except
alkaline cell testing. Anyhow, it seems my $10 worth of el-cheeso
batteries were a good buy . . . the "bunny" couldn't outrun them.
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: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: Battery Test |
>I've been exercising the CBA-II pretty much 24/7 ........ Bob . . .
Bob et al.
This follows pretty well what is published here:
http://www.zbattery.com/zbattery/batteryinfo.html
If I can influence this test....there is such a huge difference in 9V
batteries that to buy a low-performing one for anything critical seems
almost dangerous. Perhaps you can look at 9V batteries in you test?
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Battery Test |
>
>
>
> >I've been exercising the CBA-II pretty much 24/7 ........ Bob . . .
>
>Bob et al.
>
>This follows pretty well what is published here:
>
>http://www.zbattery.com/zbattery/batteryinfo.html
Aha! The repeatable experiment reigns supreme.
>If I can influence this test....there is such a huge difference in 9V
>batteries that to buy a low-performing one for anything critical seems
>almost dangerous. Perhaps you can look at 9V batteries in you test?
Hadn't considered those puppies. The same sale where I picked
up the AA cells has some 9v. I'll drop by and pick some up.
Thanks!
Bob . . .
________________________________________________________________________________
| Subject: | Just an Expensive Hobby?!?!?! |
| From: | "Lloyd, Daniel R." <LloydDR(at)wernerco.com> |
My wife's view on it is that it is an expensive baby sitter, but with it
she always knows where I am at, just open the garage door and I am
there, granted I am spending more money as I am standing there, but she
thinks it is better than a boat, which falls into the other expensive
hobby!
-----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: Just an Expensive Hobby?!?!?!
>
>
>AeroElectric-List message previously posted by: "Robert L. Nuckolls,
III"
>
>
> <<........skip.......This IS after all, just an expensive
>hobby......skip......Bob>>
>
>5/1/205
>
>Now, in addition to the pornography filter on my computer, I will have
to
>add a heresy filter so that my wife is not exposed to such damning
words!!
Do you mean you've been able to convince her that it was
anything else? Hmmmm . . . I did hear a comment from a wife
at OSH a number of years ago wherein she expressed thankfulness
for her husband's airplane project. She didn't elaborate as
to what his alternative activities might be. The
not-so-obvious possibilities are indeed endless. I guess I'll
have to categorize that statement as not belonging to the set
of simple-ideas pertaining to the OBAM aviation community.
I humbly stand corrected.
The simple idea of 'hobby' is not universally applicable . . .
but I think 'expensive' still is.
Bob . . .
________________________________________________________________________________
| From: | "bob rundle" <bobrundle2(at)hotmail.com> |
I posted a question about this a while back and got no response so I'll ask
smaller groups of questions instead.
I have an EIS engine monitor from Grand Rapids Technologies. It contains
all required info I need except current flow.
I'm also installing the single battery, dual alt using the SD-8. In your
opinion should I install 2 shunts and monitor the current at these spots?
What benefit does this provide me? If so I'll install a single ammeter and a
switch to go from main alt to stby alt.
The shunt on the main alt circuit indicates that it must be attached with 6
inches in length of less. Does this mean these shunts are typically
installed in the engine side of the firewall?
Thank you
BobR
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: Shunts & stuff |
Bob R.
Presumably you are aware of the Hall Effect current sensor that GRT
sells for $60.
If you really want to know the amps, that avoids having to install
shunts and if you so desire you can run the B-lead from both alternators
through it. I was not willing to install shunts but the hall effect
sensor is just a doughnut with about a 1" hole that you run a wire (or
several) through. There is no particular need to know the current
though. The voltage tells you what you need to know and the EIS gives
you high and low voltage warnings as well.
Ken
bob rundle wrote:
>
>I posted a question about this a while back and got no response so I'll ask
>smaller groups of questions instead.
>
>I have an EIS engine monitor from Grand Rapids Technologies. It contains
>all required info I need except current flow.
>
>I'm also installing the single battery, dual alt using the SD-8. In your
>opinion should I install 2 shunts and monitor the current at these spots?
>What benefit does this provide me? If so I'll install a single ammeter and a
>switch to go from main alt to stby alt.
>
>The shunt on the main alt circuit indicates that it must be attached with 6
>inches in length of less. Does this mean these shunts are typically
>installed in the engine side of the firewall?
>
>Thank you
>BobR
>
>
________________________________________________________________________________
| From: | Earl_Schroeder <Earl_Schroeder(at)juno.com> |
| Subject: | Re: Small pidg terminals |
A possible solution to a 'skinny' wire and a bit too large terminal that
I've used for 30+ years is to double over the wire before inserting into
the terminal. Sometimes trimming a strand or two at the bend is
necessary. Using stranded wire is assumed. Earl
N1deltawhiskey(at)aol.com wrote:
>
>If I interpret Ken's question correctly, he has some terminals with a smaller
>barrel than the usual red sleeved terminals for 20-24 wire. I have some of
>these as well (1/8" wide I believe for use on microswitches) and the issue I
>found was that the red position on the B&C crimper would not clamp sufficiently
>to prevent the #22 wire from being pulled out under load. I had to apply an
>additional tighter crimp with pliars that would close more tightly to get a
>connection that I could not pull apart.
>
>Regards, Doug Windhorn
>
>
>In a message dated 02-May-05 6:28:34 Pacific Standard Time,
>b.nuckolls(at)cox.net writes:
>
>
>
>
>
>>
>>I'm working on upgrading and intercom and a couple of instruments. The
>>avionics were set up to use a terminal strip and the old intercom harness
>>had some small PIDG terminals specified for 26-22 AWG, yellow color. I've
>>found a source for these terminals, but was wondering about a crimper. The
>>"good and cheap" crimpers all seem to have the three red,blue,yellow
>>postions, but nothing for the small yellow terminals.
>>
>>Am I stuck buying one of the expensive crimpers? Should I just go ahead
>>and use the red 22-18 AWG terminals? The wire is 22 AWG.
>>
>>
>
> The red terminals are slightly larger at the wire barrel but
> if they fit into your available space, they'll be fine too.
>
> Bob . . .
>
>
>
>
________________________________________________________________________________
| Subject: | Just an Expensive Hobby?!?!?! |
| From: | "David Glauser" <david.glauser(at)xpsystems.com> |
I tell my wife that I ought to be able to spend more on aircraft than
otherwise, since because I jumped directly from motorcycles to aircraft,
bypassing boats altogether, I saved us thousands and thousands of
dollars that ought by rights be applicable to planes.
dg
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Lloyd, Daniel R.
Subject: RE: AeroElectric-List: Just an Expensive Hobby?!?!?!
-->
My wife's view on it is that it is an expensive baby sitter, but with it
she always knows where I am at, just open the garage door and I am
there, granted I am spending more money as I am standing there, but she
thinks it is better than a boat, which falls into the other expensive
hobby!
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Starter contactor? |
>
>
>
>Bob:
>
>I sent this to through your website, but thought I should post it here.
>
>We're building an RV-10 and generally following your Z-14 diagram. The
>idea I had I wanted to run by you was to wire the starter contactor directly
>to the battery, instead of through the battery contactor.
>Advantages:
>1)less connections for loss between batt and starter;
>2) battery contactor can
>be smaller since it doesn't have to handle starting loads.
>
>Disadvantages:
>no way to turn off a stuck starter contactor.
This is the big one. I'm aware of two Glasairs that suffered
stuck starter contactors with a bypassed master relay . . . both
suffered battery damage and one hurt the starter.
>I've got a real nice starter contactor, so maybe that helps against that
>concern. We have a 24 volt system in the plane and good contactors have
>been hard to track down. What do you think?
Yup, all that 28-volt stuff is "aircraft" and therefore
low volume and blessed with more holy water than one usually
asks for. What's the 28v power requirement for the
Avidyne stuff. As you mentioned in your direct e-mail,
perhaps some boosters would be cost effective and let
you run a more generic 14v system.
Tell us more about the airplane . . . the mission and your
design goals.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | El-Cheeso 9v Battery tests |
Took a brand new Eveready Gold 9v out of the package
and tested it against the house brand 9v battery that
cost me 1/3rd as much. Here's the plots:
http://www.aeroelectric.com/Pictures/El-Cheeso_Battery_Test_2.jpg
The red plot is the Eveready.
Bob . . .
________________________________________________________________________________
| From: | "Bob Barrow" <bobbarrow10(at)hotmail.com> |
| Subject: | Low voltage and high voltage |
Because I was not going to have any aerials in my wings I figured it would
be safe to run the high voltage (strobe coax) and low voltage power wires
(nav lights etc) together in the one conduit. But now some-one tells me that
high voltage and low voltage do not good bedfellows make (noise problem).
I've finished the wings now and it will be difficult to instal a new run of
seperate grommets for the coax cable (difficult, but not impossible). Is it
really advisable to seperate the coax, and if so...by what distance.
Are you right for each other? Find out with our Love Calculator:
http://fun.mobiledownloads.com.au/191191/index.wl?page=191191text
________________________________________________________________________________
| From: | Harley <harley(at)AgelessWings.com> |
| Subject: | Re: El-Cheeso 9v Battery tests |
Very interesting , Bob! I feel a lot better about buying the batteries
with my local grocery store chain name on them (Wegman's)for half the
big name price!
Any possibility that that difference may have been due to one extra bad
Eveready, and one extra good Kroger? Wonder how they'd do if a random
number were averaged (not asking you to do it...just wondering! )
And, has anyone else ever done this (other than the manufacturer )
and posted comparisons between other brands as well such as Duracell and
Ray-O-Vac (had very little luck with Ray-O-Vac myself...seems they leak
a lot) or even the so-called better versions of the batteries, like the
Eveready Gold?
Harley Dixon
Robert L. Nuckolls, III wrote:
>
>
>Took a brand new Eveready Gold 9v out of the package
>and tested it against the house brand 9v battery that
>cost me 1/3rd as much. Here's the plots:
>
>http://www.aeroelectric.com/Pictures/El-Cheeso_Battery_Test_2.jpg
>
>The red plot is the Eveready.
>
>
> Bob . . .
>
>
>
>
________________________________________________________________________________
| From: | Harley <harley(at)AgelessWings.com> |
| Subject: | Re: El-Cheeso 9v Battery tests |
Bob...
>>or even the so-called better versions of the batteries, like the
Eveready Gold?<<
Well, now that I'm a bit more awake and have had my cup of coffee (well,
half of it ) I see that that WAS an Eveready gold that you used!
Hmmm...not very impressive at all...but they have a pretty label.
Harley
Harley wrote:
>
>Very interesting , Bob! I feel a lot better about buying the batteries
>with my local grocery store chain name on them (Wegman's)for half the
>big name price!
>
>Any possibility that that difference may have been due to one extra bad
>Eveready, and one extra good Kroger? Wonder how they'd do if a random
>number were averaged (not asking you to do it...just wondering! )
>
>And, has anyone else ever done this (other than the manufacturer )
>and posted comparisons between other brands as well such as Duracell and
>Ray-O-Vac (had very little luck with Ray-O-Vac myself...seems they leak
>a lot) or even the so-called better versions of the batteries, like the
>Eveready Gold?
>
>Harley Dixon
>
>
>Robert L. Nuckolls, III wrote:
>
>
>
>>
>>
>>Took a brand new Eveready Gold 9v out of the package
>>and tested it against the house brand 9v battery that
>>cost me 1/3rd as much. Here's the plots:
>>
>>http://www.aeroelectric.com/Pictures/El-Cheeso_Battery_Test_2.jpg
>>
>>The red plot is the Eveready.
>>
>>
>> Bob . . .
>>
>>
>>
>>
>>
>>
>
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Low voltage and high voltage |
>
>
>
>Because I was not going to have any aerials in my wings I figured it would
>be safe to run the high voltage (strobe coax) and low voltage power wires
>(nav lights etc) together in the one conduit. But now some-one tells me that
>high voltage and low voltage do not good bedfellows make (noise problem).
>
>I've finished the wings now and it will be difficult to instal a new run of
>seperate grommets for the coax cable (difficult, but not impossible). Is it
>really advisable to seperate the coax, and if so...by what distance.
Don't worry about it. The "high voltage" problem is taken care of by
the shielding on the strobe fixture cable. The BIGGEST problem is
magnetic coupling which is taken care of by making the strobe cable
a twisted trio of wires.
Probability of coupling significant noise energy into the SYSTEM
via the wires which normally exist in the wings (lighting and
pitot heat) is extremely low. Coax cables are also quite resistant
to any form of noise coupling. Most strobe noises in are directly
radiated from strobe light fixtures into the antenna at the
wingtip. This is HARD to fix. Most wingtip antennas are VOR
system antennas where one very seldom listens to the audio
so it doesn't represent an operational problem. Just in case you
DO use a VOR station to receive advisories or as a COM remote,
you can turn off the strobes for the short duration of the
communication. Strobe noise does not degrade VOR nav function.
Bob . . .
________________________________________________________________________________
| Subject: | El-Cheeso 9v Battery tests |
| From: | "Lloyd, Daniel R." <LloydDR(at)wernerco.com> |
Have you done this with the newer Duracell Max, and the new energizers?
I would be interested in knowing if the premium we pay for those is
worth it?
-----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: AeroElectric-List: El-Cheeso 9v Battery tests
Took a brand new Eveready Gold 9v out of the package
and tested it against the house brand 9v battery that
cost me 1/3rd as much. Here's the plots:
http://www.aeroelectric.com/Pictures/El-Cheeso_Battery_Test_2.jpg
The red plot is the Eveready.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: El-Cheeso 9v Battery tests |
>
>Very interesting , Bob! I feel a lot better about buying the batteries
>with my local grocery store chain name on them (Wegman's)for half the
>big name price!
>
>Any possibility that that difference may have been due to one extra bad
>Eveready, and one extra good Kroger? Wonder how they'd do if a random
>number were averaged (not asking you to do it...just wondering! )
>
>And, has anyone else ever done this (other than the manufacturer )
>and posted comparisons between other brands as well such as Duracell and
>Ray-O-Vac (had very little luck with Ray-O-Vac myself...seems they leak
>a lot) or even the so-called better versions of the batteries, like the
>Eveready Gold?
>
>Harley Dixon
Good questions. Yes, lots of folks have been doing these kinds of
tests. One Lister gave us a link yesterday:
http://www.zbattery.com/zbattery/batteryinfo.html
I did an article on the topic a few years ago at:
http://aeroelectric.com/articles/AA_Bat_Test.pdf
After thinking through the cell manufacturing and marketing
process, I've concluded that cells are much like soft drinks.
VERY little in the way of raw materials and long on
manufacturing machines, marketing and transportation
costs. Most of cost to bring a cell to your point
of sale has little to do with cell quality. I'm told that
many private brand cells are made by the same
folk that do the nationally advertised brands . . . which
makes sense too. Why set up a factory to address a tiny
fraction of 1% of the total market. There's no practical
reason or advantage in producing a good-better-best array of
products.Buy in bulk with new labels from the 'big' guys
and save yourself a lot of trouble, cost and you can offer
an exemplar product to boot!
I'll continue to look at various battery cell opportunities.
If any of you have a Kroger grocery store affiliate in the
neighborhood, they're currently running a $1 sale on a 4-pack
of AA alkaline cells . . . a very good price for a good battery.
Interestingly enough, their 8-pack and 12-pack offerings are
not on sale. So the pegs for the larger packages are full,
the 4-pack pegs are empty. But the sale goes through 5-24
and you can usually get a 'rain' check on out-of-stock items
before the sale ends. I'm waiting for the pegs to fill up
at my local stores so I can buy another $10 worth . . .
Caution . . . be wary of special trips to the store
to get this offer. The $time$ you'll spend to do this
may more than wash out the savings on the cells you
do buy . . . unless you're looking for $100 worth or
something like that. These cells have an exceptional
shelf life so they're worth grabbing up in quantity
when the opportunity presents itself.
Bob . . .
________________________________________________________________________________
| From: | Harley <harley(at)AgelessWings.com> |
| Subject: | Re: El-Cheeso 9v Battery tests |
<>
I can certainly attest to that. I spent 32 years working for the
pharmaceutical company that made and marketed Desenex foot powder, among
many other products both over-the-counter and prescription.
(Pennwalt/Fisons/Celltech)
I specifically mention the Desenex, because we used to fill orders for
Wal-Mart's athlete's foot powder as well.
We would run half of a batch of the Desenex, shut down at lunch and
while eating, the line people would change over the containers on the
line to Wal-Mart's. After lunch, we would continue packaging...same
product from the same batch! Only difference was the container.
Half of it sold at $4.99 a can as Desenex, and the other half at $1.99
as Wal-Mart!
BTW...while I'm on this topic and if any of you were in the army in the
1960s and 70s, the little olive drab pepper type shaker cans of foot
powder you got in the service was Desenex. Same deal as Wal-Mart, but
reversed...when we won an army contract, we'd change the line over to
the little OD cans, but fill them with Desenex, without the perfume.
Sold them to the army with one fewer ingredient in 2 color cans for five
times as much as the same amount of Desenex would have sold for in the
bright yellow cans. And we were the low bidder!
Harley
Robert L. Nuckolls, III wrote:
>
>
>
>
>>
>>Very interesting , Bob! I feel a lot better about buying the batteries
>>with my local grocery store chain name on them (Wegman's)for half the
>>big name price!
>>
>>Any possibility that that difference may have been due to one extra bad
>>Eveready, and one extra good Kroger? Wonder how they'd do if a random
>>number were averaged (not asking you to do it...just wondering! )
>>
>>And, has anyone else ever done this (other than the manufacturer )
>>and posted comparisons between other brands as well such as Duracell and
>>Ray-O-Vac (had very little luck with Ray-O-Vac myself...seems they leak
>>a lot) or even the so-called better versions of the batteries, like the
>>Eveready Gold?
>>
>>Harley Dixon
>>
>>
>
> Good questions. Yes, lots of folks have been doing these kinds of
> tests. One Lister gave us a link yesterday:
>
>http://www.zbattery.com/zbattery/batteryinfo.html
>
> I did an article on the topic a few years ago at:
>
>http://aeroelectric.com/articles/AA_Bat_Test.pdf
>
> After thinking through the cell manufacturing and marketing
> process, I've concluded that cells are much like soft drinks.
> VERY little in the way of raw materials and long on
> manufacturing machines, marketing and transportation
> costs. Most of cost to bring a cell to your point
> of sale has little to do with cell quality. I'm told that
> many private brand cells are made by the same
> folk that do the nationally advertised brands . . . which
> makes sense too. Why set up a factory to address a tiny
> fraction of 1% of the total market. There's no practical
> reason or advantage in producing a good-better-best array of
> products.Buy in bulk with new labels from the 'big' guys
> and save yourself a lot of trouble, cost and you can offer
> an exemplar product to boot!
>
> I'll continue to look at various battery cell opportunities.
> If any of you have a Kroger grocery store affiliate in the
> neighborhood, they're currently running a $1 sale on a 4-pack
> of AA alkaline cells . . . a very good price for a good battery.
> Interestingly enough, their 8-pack and 12-pack offerings are
> not on sale. So the pegs for the larger packages are full,
> the 4-pack pegs are empty. But the sale goes through 5-24
> and you can usually get a 'rain' check on out-of-stock items
> before the sale ends. I'm waiting for the pegs to fill up
> at my local stores so I can buy another $10 worth . . .
>
> Caution . . . be wary of special trips to the store
> to get this offer. The $time$ you'll spend to do this
> may more than wash out the savings on the cells you
> do buy . . . unless you're looking for $100 worth or
> something like that. These cells have an exceptional
> shelf life so they're worth grabbing up in quantity
> when the opportunity presents itself.
>
> Bob . . .
>
>
>
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | RE: El-Cheeso 9v Battery tests |
>Have you done this with the newer Duracell Max, and the new energizers?
>I would be interested in knowing if the premium we pay for those is
>worth it?
Batteries--
There are many ways of determining the "Best" battery for an application.
The most common are:
1) Actual cost per amp-hour;
2) Total useable energy;
3) Price.
But a battery and its application are complementary. There is no "best"
battery any more than there is a "best" airplane. The generic factors in
this equation are:
1) Expected usage schedule;
2) Weight;
3) Rechargeable or not;
4) Temperature;
5) Depth of cycle;
6) Disposal;
7) Spillage hazards;
8) Flammability;
9) Reliability....
....and uncountable other considerations. Is the tested battery the same
construction and ingredients from year to year? Who knows? If I were making
batteries, I'd issue a new revision every week.
A Google search of "battery comparison" yields a treasure trove of
information.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
________________________________________________________________________________
| From: | "Leo Corbalis" <leocorbalis(at)sbcglobal.net> |
| Subject: | Re: Shunts & stuff |
Be cheap. I have a GRT EIS too. After a flight of an hour, turn off all the
extra stuff transponder, strobes etc. The next day turn on the master
switch. Turn off everything else (pull fuses if necessary) and read the EIS
voltage. Set that as the lower limit. Try it out. If you get low volt alarms
at idle set it a smidge lower so the alarm stops. Landing lites on final
should be included in the test. Now when the alarm comes ON your alternator
is not charging enough. "Houston - we have a problem". One less clock on
the panel to watch.
Leo Corbalis
----- Original Message -----
From: "Ken" <klehman(at)albedo.net>
Subject: Re: AeroElectric-List: Shunts & stuff
>>
>>I posted a question about this a while back and got no response so I'll
>>ask
>>smaller groups of questions instead.
>>
>>I have an EIS engine monitor from Grand Rapids Technologies. It contains
>>all required info I need except current flow.
>>>>
>>
>
>
>
________________________________________________________________________________
| From: | "Larry E. James" <larry(at)ncproto.com> |
| Subject: | Re: basic reasoning for system architecture |
>What am I missing ??
Not a thing I can see. My recommendation?
Go with Z-11, rear mounted battery, 2AWG feeders
to the front. Install battery in simple tray that
captures the footprint. Strap it down with two, 2"
web-straps and nylon buckles. If you need to upsize
the battery later, it's really easy to do. The battery
can lay down or stand on end. I'd position it to drop
the height above the mounting surface to a
minimum, i.e.
lay on side. I don't think you need two. Try a 24
a.h.
battery to start.
Z-13 is an easy upgrade later, so is adding a second
battery or upsizing the first battery. You're going
to have a system with no more switches than the
present
certified fleet with much more attractive options.
Bob . . .
Thanks Bob,
So I have now narrowed the field to Z-11, Z-12, and Z-13 :-)
I can eliminate Z-11 now because now that my head is into
the wiring thing; I want to do the job the way I want it
...... no sense in coming back later to change it. I have
switched from my original dual battery / single alternator
configuration based on the reasoning expressed in this
thread and a discussion I had with Bill at B&C. He was very
helpful (and patient) and made a few more points that I had
not considered:
1) if a second battery is my backup; it has a limited time
of endurance (albeit plenty of time to get on the ground)
2) a second alternator has an unlimited time of endurance
3) a second alternator (SD-8) saves 12 lbs over the second
battery
4) the SD-8 puts out enough to power any essential
electrical requirements - although it will be "noisy" power
and radios may not work as well
5) battery failure (open battery) is probably the least
likely or known source of electrical system failure (my
words, but true to the meaning)
So, I'm liking the idea of a single battery / dual
alternator configuration with the second alternator being
the SD-8. Pretty tidy little package and you have already
published a schematic (Z-13). The only issue I know of that
is left is engine ignition. I'm currently planning on one
"magneto" Lasar and one "electronic" E-mag or P-mag ?? Are
there any gotchas in here ??
cheers,
Larry
________________________________________________________________________________
| From: | "William Yamokoski" <yamokosk(at)lakemichigancollege.edu> |
| Subject: | Radio Noise Redux |
Ok folks, here's the story...
Been dealing with noise on transmission from my MicroAir 760. I have
the following observations:
Only occurs on transmission
Occurs no matter what headset or jacks (pilot/copilot) combination I use
At low rpm, sounds like a machine gun. Add a little rpm , the machine
gun gets faster and maybe a little higher pitched. Keep adding rpm and
the gun gets too fast to make out individual noises...gets to be a big
blur
Putting my alternator breaker/switch in the off position has no effect
Individually turning off everything I can and still maintian engine
running has no effect
Connecting radio power to an otherwise empty always-hot battery bus has
no effect
Using a separate 12v battery as radio power, i.e., getting out of the
aircraft electrical system, makes the problem disappear.
My electrical system is Bob's two battery/one alternator system
I have a fuel-injected subaru engine and Quinti electrical prop. I
have not checked spark plugs or plug wires yet.
Any thoughts on possible sources of this noise? I'm about ready to
just keep a goodly supply of batteries on hand and just use the radio
that way :)
Thanks very much for any ideas.
Bill Yamokoski, N4970Y
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Radio Noise Redux |
>
>
>Ok folks, here's the story...
>
>Been dealing with noise on transmission from my MicroAir 760. I have
>the following observations:
>
>Only occurs on transmission
>
>Occurs no matter what headset or jacks (pilot/copilot) combination I use
>
>At low rpm, sounds like a machine gun. Add a little rpm , the machine
>gun gets faster and maybe a little higher pitched. Keep adding rpm and
>the gun gets too fast to make out individual noises...gets to be a big
>blur
>
>Putting my alternator breaker/switch in the off position has no effect
>
>Individually turning off everything I can and still maintian engine
>running has no effect
>
>Connecting radio power to an otherwise empty always-hot battery bus has
>no effect
>
>Using a separate 12v battery as radio power, i.e., getting out of the
>aircraft electrical system, makes the problem disappear.
>
>My electrical system is Bob's two battery/one alternator system
>
>I have a fuel-injected subaru engine and Quinti electrical prop. I
>have not checked spark plugs or plug wires yet.
>
>Any thoughts on possible sources of this noise? I'm about ready to
>just keep a goodly supply of batteries on hand and just use the radio
>that way :)
>Thanks very much for any ideas.
Sounds like ignition noise getting into the mic audio. Try
pushing the mic hi leads out of their pins on the back of the
radio (pins 1 and 3 assuming you're using both). Key up the
radio with mic audio leads disconnected and see if the noise
goes away.
I suspect it will. Have you insulated the mic and headset jacks
from airframe ground? See:
http://www.aeroelectric.com/Pictures/s890-1.jpg
Bob . . .
________________________________________________________________________________
| From: | Dave Nellis <truflite(at)yahoo.com> |
| Subject: | Re: Radio Noise Redux |
Bill,
We had a similar problem with our club 182. It would
make the VOR go inop. We had an avionics shop look at
it and they put a capacitor across the field
terminal(?) on the alternator and ground, I believe.
Fixed it right up. Might ask your favorite radio shop
about it.
Dave Nellis
--- William Yamokoski
wrote:
> Yamokoski"
>
> Ok folks, here's the story...
>
> Been dealing with noise on transmission from my
> MicroAir 760. I have
> the following observations:
>
> Only occurs on transmission
>
> Occurs no matter what headset or jacks
> (pilot/copilot) combination I use
>
> At low rpm, sounds like a machine gun. Add a
> little rpm , the machine
> gun gets faster and maybe a little higher pitched.
> Keep adding rpm and
> the gun gets too fast to make out individual
> noises...gets to be a big
> blur
>
> Putting my alternator breaker/switch in the off
> position has no effect
>
> Individually turning off everything I can and still
> maintian engine
> running has no effect
>
> Connecting radio power to an otherwise empty
> always-hot battery bus has
> no effect
>
> Using a separate 12v battery as radio power, i.e.,
> getting out of the
> aircraft electrical system, makes the problem
> disappear.
>
> My electrical system is Bob's two battery/one
> alternator system
>
> I have a fuel-injected subaru engine and Quinti
> electrical prop. I
> have not checked spark plugs or plug wires yet.
>
> Any thoughts on possible sources of this noise?
> I'm about ready to
> just keep a goodly supply of batteries on hand and
> just use the radio
> that way :)
> Thanks very much for any ideas.
>
> Bill Yamokoski, N4970Y
>
>
>
> browse
> Subscriptions page,
> FAQ,
>
>
>
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Radio Noise Redux |
>
>Bill,
>
>We had a similar problem with our club 182. It would
>make the VOR go inop. We had an avionics shop look at
>it and they put a capacitor across the field
>terminal(?) on the alternator and ground, I believe.
>Fixed it right up. Might ask your favorite radio shop
>about it.
he says it's still there with the alternator off . . .and
it changes rate with engine rpm. The "machine gun" reference
sounds more like ignition than anything associated with
the alternator.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | El-Cheeso batteries follow up tests . . . |
Ran a second name-brand 9v and a second house brand battery
over the CBA-II to get the data. Here's the plots:
http://www.aeroelectric.com/Pictures/El-Cheeso_Battery_Test_3.jpg
If you save this image to your hard drive and then view it
outside your browser (or dump it to printer) you can read the
fine text better.
The pair of house brand (Krogers) were in the same ballpark
while a Panasonic and Eveready Gold 9v batteries gave up at
about 2/3 the capacity.
Now, these tests were run at 100 mA which is REAL hard on
9v batteries. It may be that a similar collection of batteries
would come out closer in capacity if the loads were lighter
and more in line with the way 9v batteries are usually loaded.
Like 10-20 mA. This may be a case of all the examples having
about the same chemical capacity but the Krogers having lower
internal resistance (I'll go measure that tomorrow) such that
they do a better job at high rate discharge. In any case,
the notion that a battery needs to have a recognized name
to be considered for your needs is not backed up by the
experiment described above.
Bob . . .
________________________________________________________________________________
| From: | "Brian Kraut" <brian.kraut(at)engalt.com> |
| Subject: | El-Cheeso batteries follow up tests . . . |
Hmmm, now that you have killed a bunch of batteries how many of the more
economical ones do you have to use a year to make the experiment break even?
Brian Kraut
Engineering Alternatives, Inc.
www.engalt.com
-----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: AeroElectric-List: El-Cheeso batteries follow up tests . . .
Ran a second name-brand 9v and a second house brand battery
over the CBA-II to get the data. Here's the plots:
http://www.aeroelectric.com/Pictures/El-Cheeso_Battery_Test_3.jpg
If you save this image to your hard drive and then view it
outside your browser (or dump it to printer) you can read the
fine text better.
The pair of house brand (Krogers) were in the same ballpark
while a Panasonic and Eveready Gold 9v batteries gave up at
about 2/3 the capacity.
Now, these tests were run at 100 mA which is REAL hard on
9v batteries. It may be that a similar collection of batteries
would come out closer in capacity if the loads were lighter
and more in line with the way 9v batteries are usually loaded.
Like 10-20 mA. This may be a case of all the examples having
about the same chemical capacity but the Krogers having lower
internal resistance (I'll go measure that tomorrow) such that
they do a better job at high rate discharge. In any case,
the notion that a battery needs to have a recognized name
to be considered for your needs is not backed up by the
experiment described above.
Bob . . .
________________________________________________________________________________
| From: | "n801bh(at)netzero.com" <n801bh(at)NetZero.com> |
| Subject: | Re: Radio Noise Redux |
electrical system, makes the problem disappear.
My electrical system is Bob's two battery/one alternator system
I have a fuel-injected subaru engine and Quinti electrical prop. I
have not checked spark plugs or plug wires yet.
Any thoughts on possible sources of this noise? I'm about ready to
just keep a goodly supply of batteries on hand and just use the radio
that way :)
Thanks very much for any ideas.
Bill Yamokoski, N4970Y
/////////////////////////////////////////////////////////////////
I will chime in here. After 60 hours of flying without any noise in my electrical
system I was experimenting with different spark plug heat ranges for my motor.
The local parts store didn't have any Champion RC9YC plugs so they crossed
over that number to a NGK plug. Motor ran fine but the noise in the intercom
was extreme. The NGK plugs were clearly marked R for resistor but I now know they
didn't surpress ingition noise. I took them back and got some Champion RC12YC
ones like I took out and installed them. Walla,, the noise was gone again.
Bosch, AC or other plugs might have been ok too but I happened to get NGK's.
I don't work or even prefer Champions but this unusual test did suggest a bad
thing. I am running a V-8 Ford, MSD ignition, yada, yada, yada,. My suggestion
would be to spend a few bucks and change wires and plugs to experiment.
Ben Haas
N801BH
www.haaspowerair.com
________________________________________________________________________________
| From: | "John D. Heath" <Alto_Q(at)direcway.com> |
| Subject: | Re: Radio Noise Redux |
Secondary Ignition, Spark plug wire arching to ground, etc.
John D. Heath
----- Original Message -----
From: "William Yamokoski" <yamokosk(at)lakemichigancollege.edu>
Subject: AeroElectric-List: Radio Noise Redux
>
>
> Ok folks, here's the story...
>
> Been dealing with noise on transmission from my MicroAir 760. I have
> the following observations:
>
> Only occurs on transmission
>
> Occurs no matter what headset or jacks (pilot/copilot) combination I use
>
> At low rpm, sounds like a machine gun. Add a little rpm , the machine
> gun gets faster and maybe a little higher pitched. Keep adding rpm and
> the gun gets too fast to make out individual noises...gets to be a big
> blur
>
> Putting my alternator breaker/switch in the off position has no effect
>
> Individually turning off everything I can and still maintian engine
> running has no effect
>
> Connecting radio power to an otherwise empty always-hot battery bus has
> no effect
>
> Using a separate 12v battery as radio power, i.e., getting out of the
> aircraft electrical system, makes the problem disappear.
>
> My electrical system is Bob's two battery/one alternator system
>
> I have a fuel-injected subaru engine and Quinti electrical prop. I
> have not checked spark plugs or plug wires yet.
>
> Any thoughts on possible sources of this noise? I'm about ready to
> just keep a goodly supply of batteries on hand and just use the radio
> that way :)
> Thanks very much for any ideas.
>
> Bill Yamokoski, N4970Y
>
>
>
________________________________________________________________________________
| From: | Harley <harley(at)AgelessWings.com> |
| Subject: | Bob Nuckolls, in person |
Morning, Everyone...
If any of you are curious, like I was, as to who Bob Nuckolls is and
what he sounds like, and have yet to see him at a seminar or Oshkosh, I
found this interview with him.
Besides now knowing a little more about him (not the least what he
sounds like ) it's very informative, as to his goals and experience.
http://www.worldtalkradio.com/playlist.asp?SegmentID=13189
Harley Dixon
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> . |
| Subject: | El-Cheeso batteries follow up tests . . |
.
.
>
>
>Hmmm, now that you have killed a bunch of batteries how many of the more
>economical ones do you have to use a year to make the experiment break even?
Educational endeavors almost never 'break even' until you share
what is learned as a teacher -or- apply what is learned toward elegant
solutions. You spend a ton of $time$ going to college . . . and
when you get out, you're WAY below break even. It's what
you do with the knowledge and skills afterward that determines
the return on investment. I treat my career as an ongoing
educational process that demands a continuous investment in $time$
for learning. I carry around a lot of data that may never be tapped
in a design task. So it seems the best use of any knowledge is to
share it with as many folks as possible. Knowledge is the one
commodity that does not diminish in value the more it is shared.
Being able to share those data with folks here on the list is the
first opportunity to reap benefits from the investment. As to
application of this information into future design efforts,
who knows? But like data store in any library, you can't tap
the information contained in a book if the book is not on the
shelf waiting to be read.
Bob . . .
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | RE: El-Cheeso batteries |
Bob,
You need to enlist a cute secretary to stage a "9V Battery Race". Entry fee
$1 to a worthwhile charity. The entrants must write their name on their own
new 9V battery. The rest is details. You get the data for free.
I want to suggest, as in my previous post, that the load on the battery may
produce different results--to wit: The best battery at 100 mA may not be the
best at either 10 mA or 250 mA. Batteries are very sensitive to the test
conditions.
For some applications there are great choices:
Zinc-air battery Duracell #146 . Their nominal voltage is 8.4V but they pack
in 1500 mA-hours. Their cost is very reasonable, but they should be used
only for low current-draw applications.
Lithium batteries are available in 9V sizes and are exceptional for all
tasks.
NiMH rechargeables are still the battery of choice for most portable
applications.
There are tiny little electronic up-converters that can be retrofitted to
portable devices to produce 9V from a couple AA's. These schemes are very
efficient See: http://www.siliconchip.com.au/cms/A_100886/article.html The
advantages are cost and voltage maintenance over life. This little circuit
needs to be updated with newer parts that work even better.
Ebay is the place to get great deals on batteries.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
"Competition brings out the best in products and the worst in people."
- David Sarnoff
________________________________________________________________________________
| From: | "William Yamokoski" <yamokosk(at)lakemichigancollege.edu> |
| Subject: | Re: Radio Noise Redux |
Hi Folks,
Thanks very much for the input. It certainly seemed like
ignition-related to me.
I tried Bob's suggestion of disconnecting the mic audio leads....this
had no effect on the noise. I retained this configuration and tied
the radio into the separate battery. Now I got no mike function at
all...no evidence of any transmission. The little red light on the
face of the radio did not come on. At this point I should have stepped
away, because further fiddling with things resulted in reversing
polarity on the battery and frying the radio. Sigh...
Infazed, I plugged the harness into my backup MicroAir 760 and noticed
that it came on even though both the radio and intercom ground wires
were hanging in the breeze, not connected to anything. Then I managed
to fry that radio too
This sure is fun
Any more thoughts (other than take a few days rest! I already figured
that out:)
Bill Yamokoski
________________________________________________________________________________
| From: | Richard Riley <Richard(at)RILEY.NET> |
| Subject: | An item only a true geek will love |
Ebay has an original Loewe OE333 radio, with the 3NF tube, for auction
http://tinyurl.com/7pppu
It's up to $600.
The 3NF is the first integrated circuit ever made. At the time, in
Germany, radios were taxed on how many tubes they had. Loewe responded in
1926 by building the 3nf, a single tube with several components - typically
three triodes, two capacitors and four resistors. They are works of
art. http://homepage.ntlworld.com/electricstuff/loewe.html
I've seen a few of the tubes come up on Ebay, they seem to go for about
$250-300. I've never seen one of the radios.
________________________________________________________________________________
| From: | "Sally and George" <aeronut58(at)hotmail.com> |
| Subject: | Bob Nuckolls, in person |
If you ever have a chance to attend one of the periodic seminars he puts on,
jump at it. Not only is it a pleasure to meet this nice person, but the
information that spills from his lips is like an endless stream of gold,
whether you're a Tesla or a tyro.
George Kilishek
Harley Dixon wrote:
>
>
>If any of you are curious, like I was, as to who Bob Nuckolls is and
>what he sounds like, and have yet to see him at a seminar or Oshkosh, I
>found this interview with him.
>
>Besides now knowing a little more about him (not the least what he
>sounds like ) it's very informative, as to his goals and experience.
>
>http://www.worldtalkradio.com/playlist.asp?SegmentID=13189
>
>Harley Dixon
>
>
________________________________________________________________________________
| From: | Mickey Coggins <mick-matronics(at)rv8.ch> |
| Subject: | Re: El-Cheeso batteries follow up tests . . . |
> Being able to share those data with folks here on the list is the
> first opportunity to reap benefits from the investment. ...
I can confirm that you have saved me *a lot* of money on
batteries over the past year or so. After reading your
analysis of AA batteries, I only buy Ikea "brand" batteries
here in Switzerland, and they are about 1/3 the price of
all others. They last just as long if not longer, and
with two little kids, I use these things like I used
to use diapers.
Thanks!
--
Mickey Coggins
http://www.rv8.ch/
#82007 Wiring
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: An item only a true geek will love |
>
>Ebay has an original Loewe OE333 radio, with the 3NF tube, for auction
>
>http://tinyurl.com/7pppu
>
>It's up to $600.
>
>The 3NF is the first integrated circuit ever made. At the time, in
>Germany, radios were taxed on how many tubes they had. Loewe responded in
>1926 by building the 3nf, a single tube with several components - typically
>three triodes, two capacitors and four resistors. They are works of
>art. http://homepage.ntlworld.com/electricstuff/loewe.html
>
>I've seen a few of the tubes come up on Ebay, they seem to go for about
>$250-300. I've never seen one of the radios.
Great find Richard. Thanks for sharing this. I've written
the owner of this site for permission to use some of his
photography and documentation in some of my lunchtime learning
sessions I do out at RAC.
I've got a veritable museum of antique components stacked
away in boxes. Some day, I'm going to photograph all the
parts and produce a website much like Mike's except I'll
run further afield in describing components while his
effort concentrates on glass. I need to get retired from
RAC so I can spend 8 more hours a day with this fun stuff!
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Revision 11 is in print |
Looked over a proof copy of R11 from the printer today and
gave them a green light to run the presses. If any of you
have an R10 book on order, you'll be receiving an R11 book
at the R10 price.
Folks with R10 editions in hand may download and print the update
pages found at: http://aeroelectric.com/articles/Rev11
There are three .pdf files
RIGHT CLICK these and download them to your hard drive
before you attempt to open them for viewing/printing.
Many browsers have problems opening large .pdf files
directly into Adobe Reader. Down load first, view later.
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: | "J. Mcculley" <mcculleyja(at)starpower.net> |
| Subject: | SD-8 Noisy Performance? |
7.50 BARRACUDA_HEADER_FP57 RBL: Blacklist relays.ordb
[This mail was handled by an open relay - please]
[visit <<http://ORDB.org/lookup/?host=208.59.156.131>>]
4) the SD-8 puts out enough to power any essential
electrical requirements - although it will be "noisy" power
and radios may not work as well
Larry,
Have you had some experience with the SD-8 alternator wherein you found
it to be a noise source or had a negative impact on radios?
My aircraft uses only the SD-8 for primary alternator power in a single
battery setup and it has been totally without even a trace of noise in
the radio and intercom system. I don't know of a more noise free
aircraft that I have ever flown. Granted, YMMV, but I'm just curious.
Jim McCulley
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: SD-8 Noisy Performance? |
>
>
>
>
>
>
>4) the SD-8 puts out enough to power any essential
>electrical requirements - although it will be "noisy" power
>and radios may not work as well
>
>
>Larry,
>
>Have you had some experience with the SD-8 alternator wherein you found
>it to be a noise source or had a negative impact on radios?
>
>My aircraft uses only the SD-8 for primary alternator power in a single
>battery setup and it has been totally without even a trace of noise in
>the radio and intercom system. I don't know of a more noise free
>aircraft that I have ever flown. Granted, YMMV, but I'm just curious.
I'm surprised that Bill would say such a thing. We did tests
years ago wherein the SD-8 was loaded over a range of power
settings with what I recall was a 14,000 uFd capacitor across
the output. Noise levels recorded on the 'scope were well inside
DO-160/Mil-Std-704 expectations/requirements. I.e. this combination
was no worse than any other alternator I've tested.
I looked for the traces I took but can't put my hands on them
right now. I'll publish the data if I find it.
Further, there must be many hundreds of SD-8's flying as
sole sources of engine driven power. This was the product
that launched B&C back about 1984. It was Bill's quest
to purchase front end-bell castings from our (Electro-Mech's)
vacuum pump pad mounted generators for Bonanzas that
brought Bill and I together for the first time.
The SD-8 has been studied several times over the years
for system integration issues and it's never presented
intractable problems.
Bob . . .
________________________________________________________________________________
| From: | "Martin Hone" <mctrader(at)bigpond.net.au> |
| Subject: | RE: AeroElectric-List Digest:11 Msgs - 05/05/05 |
I find it hard to believe that someone would cut the wings off because they
couldn't figure out how to get the wings off....bloody hell.
Martin Hone
Corporate Advertising
Motorcycle Trader
Mobile 0419 368 696
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
AeroElectric-List Digest Server
Subject: AeroElectric-List Digest:11 Msgs - 05/05/05
*
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Total Messages Posted Thu 05/05/05:11
Today's Message Index:
----------------------
1. 05:19 AM - Bob Nuckolls, in person (Harley)
2. 07:15 AM - Re: El-Cheeso batteries follow up tests . . (Robert L.
Nuckolls, III)
3. 07:34 AM - Re: El-Cheeso batteries (Eric M. Jones)
4. 07:51 AM - Re: Radio Noise Redux (William Yamokoski)
5. 08:00 AM - An item only a true geek will love (Richard Riley)
6. 09:01 AM - Re: Bob Nuckolls, in person (Sally and George)
7. 09:14 AM - Re: El-Cheeso batteries follow up tests . . . (Mickey
Coggins)
8. 05:53 PM - Re: An item only a true geek will love (Robert L.
Nuckolls, III)
9. 06:04 PM - Revision 11 is in print (Robert L. Nuckolls, III)
10. 07:02 PM - SD-8 Noisy Performance? (J. Mcculley)
11. 08:32 PM - Re: SD-8 Noisy Performance? (Robert L. Nuckolls, III)
________________________________ Message 1
_____________________________________
From: Harley <harley(at)AgelessWings.com>
Subject: AeroElectric-List: Bob Nuckolls, in person
-->
Morning, Everyone...
If any of you are curious, like I was, as to who Bob Nuckolls is and
what he sounds like, and have yet to see him at a seminar or Oshkosh, I
found this interview with him.
Besides now knowing a little more about him (not the least what he
sounds like ) it's very informative, as to his goals and experience.
http://www.worldtalkradio.com/playlist.asp?SegmentID=13189
Harley Dixon
________________________________ Message 2
_____________________________________
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> .
Subject: RE: AeroElectric-List: El-Cheeso batteries follow up tests . .
.
-->
________________________________________________________________________________
| From: | "Ronald J. Parigoris" <rparigor(at)SUFFOLK.LIB.NY.US> |
| Subject: | Airmaster AC200 manual switch? |
Into the panel of Europa monowheel at the moment, trying to figure out what
is needed to make on order Airmaster AC200 Manual switch inputs happy.
I got an answer from Martin that they use a DPDT rated at 5 amps. Waiting for
answer on my more pointed question.
Since I want to use a SPDT Mom-Off-Mom rated 1 amp on Ray Allen Grip, I will
need to plumb in 2 relays.
My question:
Does in fact the manual switch direct control the pitch motor, where you
would want to short the 2 leads going to the motor when in the off position
to incorporate braking? In other words just like what the pitch trim switch
does supplied by Europa (Ray Allen) where they actual use 2 SPDT switches
where COMM is output to motor and they tie ground to NC and tie posative to
NO ? Push on 1 switch and you go 1 direction, push on the other, go in other
direction, let go of both, and short 2 motor leads and get braking.
Or does the manual switch just control electronics in the AC200, and a DPDT
output should be fine.
Thx.
Ron Parigoris
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Airmaster AC200 manual switch? |
>
>
>Into the panel of Europa monowheel at the moment, trying to figure out what
>is needed to make on order Airmaster AC200 Manual switch inputs happy.
>
>I got an answer from Martin that they use a DPDT rated at 5 amps. Waiting for
>answer on my more pointed question.
>
>Since I want to use a SPDT Mom-Off-Mom rated 1 amp on Ray Allen Grip, I will
>need to plumb in 2 relays.
>
>My question:
>Does in fact the manual switch direct control the pitch motor, where you
>would want to short the 2 leads going to the motor when in the off position
>to incorporate braking? In other words just like what the pitch trim switch
>does supplied by Europa (Ray Allen) where they actual use 2 SPDT switches
>where COMM is output to motor and they tie ground to NC and tie posative to
>NO ? Push on 1 switch and you go 1 direction, push on the other, go in other
>direction, let go of both, and short 2 motor leads and get braking.
>
>Or does the manual switch just control electronics in the AC200, and a DPDT
>output should be fine.
Is this what you're trying to do?
http://www.aeroelectric.com/PPS/Flight/Trim/T5.pdf
Bob . . .
________________________________________________________________________________
| From: | "Ronald J. Parigoris" <rparigor(at)SUFFOLK.LIB.NY.US> |
| Subject: | Re: Airmaster AC200 manual switch? |
Hello Bob
Thx. for the reply.
What I am looking for is the requirements of the AC200 from the manual input.
I don't know how many amps is required.
I don't know if the trim circuit that I described, and you so eloquent sent along
is what
the AC200 is looking for. It may be that the manual switch is somehow controlling
the
electronics in the AC200 constant speed controller and not going direct to the
electric
motor. Or it could be that the output is going direct to the electric to the electric
motor, and your schematic is then perfect.
Thx.
Sincerely
Ron Parigoris
"Robert L. Nuckolls, III" wrote:
>
>
> >
> >
> >Into the panel of Europa monowheel at the moment, trying to figure out what
> >is needed to make on order Airmaster AC200 Manual switch inputs happy.
> >
> >I got an answer from Martin that they use a DPDT rated at 5 amps. Waiting for
> >answer on my more pointed question.
> >
> >Since I want to use a SPDT Mom-Off-Mom rated 1 amp on Ray Allen Grip, I will
> >need to plumb in 2 relays.
> >
> >My question:
> >Does in fact the manual switch direct control the pitch motor, where you
> >would want to short the 2 leads going to the motor when in the off position
> >to incorporate braking? In other words just like what the pitch trim switch
> >does supplied by Europa (Ray Allen) where they actual use 2 SPDT switches
> >where COMM is output to motor and they tie ground to NC and tie posative to
> >NO ? Push on 1 switch and you go 1 direction, push on the other, go in other
> >direction, let go of both, and short 2 motor leads and get braking.
> >
> >Or does the manual switch just control electronics in the AC200, and a DPDT
> >output should be fine.
>
> Is this what you're trying to do?
>
> http://www.aeroelectric.com/PPS/Flight/Trim/T5.pdf
>
> Bob . . .
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Airmaster AC200 manual switch? |
>
>
>Hello Bob
>
>Thx. for the reply.
>
>What I am looking for is the requirements of the AC200 from the manual input.
I guess I'm lost. What's the AC200?
Bob . . .
________________________________________________________________________________
| From: | "William Yamokoski" <yamokosk(at)lakemichigancollege.edu> |
| Subject: | Re: Radio Noise Redux |
Hi Folks
Just wondering what if anything I can deduce from the fact that
disconnecting audio leads had no effect on transmission noise.
Also, which of the following is most likely
1.) Ignition is making a normal noise, and some flaw in my other
wiring is allowing it in
2.) Ignition is making an abnormal noise and wiring is ok
Now that my radio life consists of using the handheld tied into ship's
antenna(which works great of course) I have much time to ponder what to
do about this ignition noise. New plugs and plug wires are on the
maintenance schedule anyway, so that issue will soon be addresses.
Again, thanks for any thoughts.
Bill Yamokoski, N4970y
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Radio Noise Redux |
>
>
>Hi Folks
> pushing the mic hi leads out of their pins on the back of the
> radio (pins 1 and 3 assuming you're using both). Key up the
> radio with mic audio leads disconnected and see if the noise
> goes away.
>
> snip
>Bob>
>Just wondering what if anything I can deduce from the fact that
>disconnecting audio leads had no effect on transmission noise.
I'm having trouble getting my arms around this one.
The only other conduction path open to the radio is
the 14v source. Do I recall correctly that you
ran the radio from an independent battery. I recall
that you had problems with the experiment setup but
did you ultimately find out if an independent supply
helped? Have you tried any kind of filters in the
radio's supply line? Like:
http://aeroelectric.com/articles/filter/RS_Noise_Filters.pdf
> Also, which of the following is most likely
>1.) Ignition is making a normal noise, and some flaw in my other
>wiring is allowing it in
>2.) Ignition is making an abnormal noise and wiring is ok
None of these can be ruled out . . . yet. #1 is most
likely but in really intractable troubleshooting efforts,
I've learned not assume anything about what's under
every rock until you turn it over and see for yourself.
>Now that my radio life consists of using the handheld tied into ship's
>antenna(which works great of course) I have much time to ponder what to
>do about this ignition noise.
If you don't hear it in the hand held, then it's not coming
in through the antenna.
> New plugs and plug wires are on the
>maintenance schedule anyway, so that issue will soon be addresses.
>Again, thanks for any thoughts.
Sure wish you lived close by. This would be an interesting
problem to tackle first hand.
Bob . . .
________________________________________________________________________________
| From: | "William Yamokoski" <yamokosk(at)lakemichigancollege.edu> |
| Subject: | Re: Radio Noise Redux |
< I'm having trouble getting my arms around this one.
The only other conduction path open to the radio is
the 14v source. Do I recall correctly that you
ran the radio from an independent battery. >
Yes...running from an independent battery eliminated the problem.
Running from ship's supply with mic pins 1 & 3 disconnected did not
eliminate noise. Running from independent battery with pins
disconnected resulted in no transmission at all, as if PTT had been
disabled. Also, when on ship's supply it didn't matter if I even had
headset mic plugged into its jack. Push pilot's PTT and hear the
machine gun. Push co-pilot's ptt with nothing plugged into either
co-pilot jack and hear the macnine gun
Once I get the fried radios back, would I learn anything by removing
the engine ground strap from the ground block and connecting the strap
directly into the ground next to the plane? Is that safe? I have a
few other components grounded to the engine side of the ground block, as
per your drawings. Any point doing the same with those, or am I just
going to fry something else?
Thanks for your thoughts Bob. I'm starting to think that life with a
handheld and portable intercom might just not be too bad :)
Bill Yamokoski
________________________________________________________________________________
| From: | "Paul McAllister" <paul.mcallister(at)qia.net> |
| Subject: | Headphone & microphone plugs |
Hi all,
The cable on my Telex headset has failed near the jack and I need to re terminate
them.. Could someone tell me a good source for a mic and phone jack. Something
with a good cable relief would be nice.
Thanks, Paul
________________________________________________________________________________
| From: | "Ronald J. Parigoris" <rparigor(at)SUFFOLK.LIB.NY.US> |
| Subject: | Re: Airmaster AC200 manual switch? |
Hello Bob
I will be using a Airmaster prop on 914UL Rotax.
The Airmaster Hub is called a AP332, it houses the electric motor and articulation
mechanism while holding Warp drive Blades. You could use the AP332 like this and
just have
an adjustable pitch prop.
Or you can add the AC200, which is a Constant speed black box controller.
http://www.airmasterpropellers.com/
Or can try http://www.airmasterpropellers.com/wa.asp?idWebPage=3474
I am pretty certain your Schematic will work with just the AP332, if it were plumbed
direct
to the electric motor.
When using the Constant speed black box controller, I downloaded as much info as
i could,
but it does not give enough detail as to what the switch does, perhaps it controls
the
motor direct somehow, or perhaps it is controlling some sort of circuit in the
AP332 that
is not direct to the motor.
Thx.
Sincerely
Ron Parigoris
"Robert L. Nuckolls, III" wrote:
>
>
> >
> >
> >Hello Bob
> >
> >Thx. for the reply.
> >
> >What I am looking for is the requirements of the AC200 from the manual input.
>
> I guess I'm lost. What's the AC200?
>
> Bob . . .
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Headphone & microphone plugs |
>
>
>Hi all,
>
>The cable on my Telex headset has failed near the jack and I need to re
>terminate them.. Could someone tell me a good source for a mic and phone
>jack. Something with a good cable relief would be nice.
I presume you're talking about PLUGS on the ends
of headset cords. The JACK is the receptacle that
mounts to the airplane.
The mil-spec mic plugs can be had from
Allied Electronics in their Switchcraft line. See
http://www.alliedelec.com/catalog/pf.asp?FN=291.pdf
The microphone plug is a Switchcraft #480
The phone plug isn't available in the mil spec version
but a good commercial substitute is:
The headphone plug is Switchcraft #250
Bob . . .
________________________________________________________________________________
| From: | Jack <jgh2(at)charter.net> |
The following is offered in the hope it will prevent others from
wasting time seeking the cause of a non-existent problem.
The "Problem".
The instrument panel was finished and it was time to be sure everything
operated properly before installing the RV-6A forward top skin.
Installed a temporary battery and used a hand held transceiver to
verify the Garmin 250XL would send and receive clearly using the IP
mounted mic and headphone jacks and PTT. Installed the PS Engineering
1000 intercom, pilot and co-pilot jacks and PTT switches, and verified
the intercom functioned properly with the com radio off. Turned the
com radio on and found the audio was very noisy whenever the intercom
broke squelch (although it was possible to transmit and receive clearly
from any of the three sets of jacks and PTT switches).
The Investigation.
Disassembled and checked: all jack solder joints, shields, isolation
washer sets, wire continuity and pin connections. Everything OK. PS
Engineering suggested charging the temporary battery. "Problem" solved.
Name withheld to protect the ignorant.
________________________________________________________________________________
| From: | "Wayne Sweet" <w_sweet(at)comcast.net> |
I have an old (15 years) Terra ECDI that some LED's are non-op. Does anyone know
if these are repairable and who does such repairs?
Wayne
________________________________________________________________________________
| From: | EuropaXSA276(at)aol.com |
| Subject: | Re: Terra 200 Nav |
Easter Avionics has some Terra / Trimbal parts. I believe the purchased the
inventory when Terra exited the general aviation biz.
Brian Skelly
Texas
Europa # A276 TriGear
See My build photos at:
http://www.europaowners.org/BrianS
________________________________________________________________________________
| From: | <bakerocb(at)cox.net> |
| Subject: | Radio Noise Redux |
5/8/2005
Hello William Yamokoski, My sympathies to you with your on going radio
problems which started out with a machine gun noise when transmitting (see
both previous edited postings below).
Maybe my experience will help. I eventually solved my problem by buying some
split ferrite beads and installing them in several different arbitrarily
selected places in my comm system -- not very scientific. The noise went
away. I took a "what ever works" attiude and haven't delved any further into
the cause. Good luck.
OC
6/16/2004
Hello Brian Lloyd, and Other Willing Experts, I have a vexing problem with
the
VHF comm portion of my Garmin 430 installed in my KIS TR-1 that I'd like
some
help with. Here is the fundamental problem scenario:
1) Start engine, talk to ground control (121.8) using Lightspeed headset,
pilot's
push to talk button, and pilot's headset jacks. Everything works normally
so taxi out and make engine run up.
2) Engine run up complete, switch to tower (133.1), try to talk using same
arrangement
as in 1). The result is a machine gun like sound when I key the transmitter
-- impossible to transmit coherently. (Rapid intermittent making and
breaking
of ground contact for PTT?). Receiver works OK.....skip...
'OC' Baker, Builder of KIS TR-1 #116 4/14/97 - 11/17/03
Date: May 04, 2005
previously from "William Yamokoski"
Subject: Radio Noise Redux
Ok folks, here's the story...Been dealing with noise on transmission from
my MicroAir 760. I have
the following observations: Only occurs on transmission. Occurs no matter
what headset or jacks (pilot/copilot) combination I use. At low rpm, sounds
like a machine gun. Add a little rpm , the machine gun gets faster and
maybe a little higher pitched. Keep adding rpm and the gun gets too fast
to make out individual noises...gets to be a big blur.....skip........Bill
Yamokoski, N4970Y
________________________________________________________________________________
| From: | Earl_Schroeder <Earl_Schroeder(at)juno.com> |
| Subject: | Re: Terra 200 Nav |
Last I heard, Gulf Coast at Lakeland does repair. I have a couple of
Terras purchased from them and when asked last year at Oshkosh, they
still offered repairs. Earl
Wayne Sweet wrote:
>
>I have an old (15 years) Terra ECDI that some LED's are non-op. Does anyone know
if these are repairable and who does such repairs?
>Wayne
>
>
>
________________________________________________________________________________
| From: | <gmcjetpilot(at)yahoo.com> |
| Subject: | OV damage to avionics: Dynon, Icom, Collins |
What would happen to your avionics if an over voltage occurred? I did not know,
so I called and asked. The over voltage would presumably be caused by a runaway
alternator or regulator malfunction. The avionics I was most interested in
was the:
-Dynon D-10 EFIS
-Icom A200 panel mounted COM
-Collins (S-Tec) TDR-950 transponder
The question: can it handle an over voltage and what damage could take place?
**Dynon EFIS D-10: all-in one EFIS unit that incorporates a color "glass" display
of all flight instruments. Dynon meets the electronics industry standard, such
as DO-160 and can handle input voltage of 10-30V and spikes of 60V for very
short period (20ms?). The main electronics are always protected, but if the
OV is extreme or duration too long, damage could occur to the unit. However the
damage would be limited and repair cost nominal.
**Icom A200: digital flip-flop digital Com. They have a statement in the user manual
that it must be off during start for protection of circuits. It also states
power source over 16V will ruin the transceiver. I got thru to customer support.
They were helpful but admitted they had limited technical information,
and he was not one of the bench guy. However he was steadfast that the radio must
be off during start and the max volts was 15.8 volts. He did not see anything
in the circuit schematics that protected the main board from the power source
(aircraft power). Therefore he speculates that any over voltage or spike would
damage the radio? Obviously disappointed, I may check a little deeper.
**Collins TDR-950: Collins transponder sold to Meggitt/S-Tec back in the late 90's.
This design goes back a decade or two, and TDR-950s made by S-Tec are the
same as units made by Collins. The TDR-950 does not have real over voltage protection
and could get fully toasted in a worst-case OV scenario. However it does
have some sacrificial components that often fail first, such as a capacitor,
transistor and series relay, saving the main boards. However if it gets past
these first few items, it can extensively damage the transponder. The Gent I
talk to is a real technical "bench guy and seen 14V units connected to 28-32volt
power. He suggest since it draws only 1.2 amps during TX a small 2 amp fuse
would protect it, since the unit will draw more amps with higher voltage, as
he stated it. Since I only have $300 into my TDR-950 I wont worry about it too
much, but may be a 1.5-2 amp fuse might be OK. Therefore if you have a TDR-950
turn it off for engine start and shutdown. S-Te
c
stopped producing them several years ago but still supports them (because Piper
makes them). Good value on the used market.
That is all I found? Of the 3 units above, two newer units and one older design,
only one has OV protection, a new non-TSO'ed unit, the Dynon. The Icom A200,
non-TSO'ed version, does not have OV protection. The TSO'ed version of the A200
is the same, no OV protection, except it meets MIL-STD 810, which is an environmental
spec, not an electrical OV protection spec (like DO-160). Any other
radios/avionics you might have info on? Or have an opinion on OV and avionics?
I would be interested.
ALTERNATORS, INTERNAL VOLTAGE REGULATORS and OV
In the never ending quest for truth and justice
I asked two large auto electrical overhaul shops about the ND alternators and OV
failures. None seen but the common failure is an OPEN field, ie quite death
but no OV.
As far as how the OV protection works in the internal voltage regulated alternators,
I am checking. The question is can the IC predict an overload or critical
transistor problem before it is a problem. I-VR report they provide detection,
protection & limiting functions for over voltage, over current, field shorts
and over temperature. The question is how?
So how can the smart IC protect an alternator from an OV? The whole case against
the I-VR is a specific transistor short. The common reason for transistor failures
is getting too hot or a thermal runaway. Transistors have very predictable
temp characteristics and can even be used as temp probe. They have a predictable
logarithmic current vs. temp relationship. It would be easy for the IC
to monitor this characteristic and shut the transistor down well before a threshold
of melt-down. That is my story and I am sticking to it. The point to all
of this is I-VR are far better than the external voltage regulators of yesterday
or even today that have ZERO internal monitoring. Is this goodness enough
to justify not installing extra OV relays? Up to you.
Common transistors used in the VRs with the IC are the FET and IBJT transistors.
As stated before, FET failure rates of transistors are in the millions of hours.
The FET is superior in almost every way, but does have the draw back of one
of its failure modes can be a short. (Rare but possible.) The IBJT-integrated
bipolar junction transistor, is a cross between the FET and BJT junction transistor,
and they are also in common use in alternator applications. The IBJTs
common failure mode will not cause an OV. Looking at the ND voltage regulator
it appears they use the IBJT or BJT, not the FET as I first thought, but I am
still checking. Again the FET is really the best you can get and is extremely
reliable. The nice thing with the IBJT is it is almost like a FET but fails
in a different way. Either way chance of failure is very very very low. It also
points to the fact every transistor type is differnt and how they are used
determines how they might fail, so stories of trans
istors
failing in one application does not mean it applies to another.
Thanks George
(PS check the capability of this IC. Note the application and protections. This
chip is not associated with any specific alternator, just interesting.)
http://www.freescale.com/files/analog/doc/data_sheet/MC33099FS.pdf
________________________________________________________________________________
| From: | <psiegel(at)fuse.net> |
| Subject: | Old Bose Headsets Cutting Out |
I have a 1946 Aeronca Champ just out of restoration. I have the older style portable
Bose noise-cancelling headsets front and back. (The kind Bose no longer
supports other than to take as a trade-in for their new headsets...don't get
me started!) They can be powered by 12v-24v. I power them with a portable 10
x 1.2v 2400 mAh nicad pack.
I also use this portable nicad pack as power for an A-22 Icom handheld radio which
has its own 600 mAh internal nicad pack and a portable Sigtronics 2-person
high noise intercom. The intercom also has an internal 9v "transistor radio"
style back-up battery.
My problem is that after about 10 minutes of flying the noise cancelling feature
in the front (noisiest) seat kicks off. When I cycle the on-off switch it just
comes back on for a few seconds.
I swapped the headsets front and back and the problem persists. I tried different
freshly cycled and fully charged nicad pack and the problem persists. I tried
to power the front headset only with two 9v "transistor radio" batteries
wired in series and the headsets work fine that way?
I wonder why the front seat headset doesn't keep working with my shared 10 cell
nicad pack? Any suggestions? Anybody know how long the old Bose headset will
operate on the two "transistor radio" style batteries?
Please be patient with me as I am new to this list!
Paul Siegel
________________________________________________________________________________
| From: | "William Yamokoski" <yamokosk(at)lakemichigancollege.edu> |
| Subject: | Re: Radio Noise Redux |
Thanks OC....at this point all suggestions are most welcome. Even more
importantly, I think I could install these things without making
anything blow up! Thanks again.
Bill Yamokoski
>>> bakerocb(at)cox.net 05/08/05 12:06 PM >>>
5/8/2005
Hello William Yamokoski, My sympathies to you with your on going radio
problems which started out with a machine gun noise when transmitting
(see
both previous edited postings below).
Maybe my experience will help. I eventually solved my problem by buying
some
split ferrite beads and installing them in several different arbitrarily
selected places in my comm system -- not very scientific. The noise went
away. I took a "what ever works" attiude and haven't delved any further
into
the cause. Good luck.
OC
6/16/2004
Hello Brian Lloyd, and Other Willing Experts, I have a vexing problem
with
the
VHF comm portion of my Garmin 430 installed in my KIS TR-1 that I'd like
some
help with. Here is the fundamental problem scenario:
1) Start engine, talk to ground control (121.8) using Lightspeed
headset,
pilot's
push to talk button, and pilot's headset jacks. Everything works
normally
so taxi out and make engine run up.
2) Engine run up complete, switch to tower (133.1), try to talk using
same
arrangement
as in 1). The result is a machine gun like sound when I key the
transmitter
-- impossible to transmit coherently. (Rapid intermittent making and
breaking
of ground contact for PTT?). Receiver works OK.....skip...
'OC' Baker, Builder of KIS TR-1 #116 4/14/97 - 11/17/03
Date: May 04, 2005
previously from "William Yamokoski"
Subject: Radio Noise Redux
Ok folks, here's the story...Been dealing with noise on transmission
from
my MicroAir 760. I have
the following observations: Only occurs on transmission. Occurs no
matter
what headset or jacks (pilot/copilot) combination I use. At low rpm,
sounds
like a machine gun. Add a little rpm , the machine gun gets faster and
maybe a little higher pitched. Keep adding rpm and the gun gets too
fast
to make out individual noises...gets to be a big
blur.....skip........Bill
Yamokoski, N4970Y
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: OV damage to avionics: Dynon, Icom, Collins |
So will a couple of 18volt transorbs after a 5 or 7.5 amp fuse offer any
real protection to an icom A200 I wonder? I guess I could set up a test
to at least confirm that the fuse pops.
Ken
gmcjetpilot(at)yahoo.com wrote:
>
>
>What would happen to your avionics if an over voltage occurred? I did not know,
so I called and asked. The over voltage would presumably be caused by a runaway
alternator or regulator malfunction. The avionics I was most interested in
was the:
>
>
>-Dynon D-10 EFIS
>
>-Icom A200 panel mounted COM
>
>-Collins (S-Tec) TDR-950 transponder
>
>
>The question: can it handle an over voltage and what damage could take place?
>
>
>**Dynon EFIS D-10: all-in one EFIS unit that incorporates a color "glass" display
of all flight instruments. Dynon meets the electronics industry standard,
such as DO-160 and can handle input voltage of 10-30V and spikes of 60V for very
short period (20ms?). The main electronics are always protected, but if the
OV is extreme or duration too long, damage could occur to the unit. However the
damage would be limited and repair cost nominal.
>
>
>**Icom A200: digital flip-flop digital Com. They have a statement in the user
manual that it must be off during start for protection of circuits. It also states
power source over 16V will ruin the transceiver. I got thru to customer support.
They were helpful but admitted they had limited technical information,
and he was not one of the bench guy. However he was steadfast that the radio
must be off during start and the max volts was 15.8 volts. He did not see anything
in the circuit schematics that protected the main board from the power source
(aircraft power). Therefore he speculates that any over voltage or spike
would damage the radio? Obviously disappointed, I may check a little deeper.
>
>
>
________________________________________________________________________________
| From: | BobsV35B(at)aol.com |
| Subject: | Re: Old Bose Headsets Cutting Out |
In a message dated 5/9/2005 5:24:25 A.M. Central Standard Time,
psiegel(at)fuse.net writes:
I wonder why the front seat headset doesn't keep working with my shared 10
cell nicad pack? Any suggestions? Anybody know how long the old Bose headset
will operate on the two "transistor radio" style batteries?
Please be patient with me as I am new to this list!
Paul Siegel
Good Morning Paul,
The symptoms you report are indicative of a voltage loss. I would check the
voltage at the connection to the Bose headsets or within the Bose controller
unit. I had a set of those first generation headsets and they worked great all
the way until they were traded in on the newer light weight Bose Xs.
However, I never did try to use them with a battery pack. Since they will
operate on either fourteen or twenty-eight volts, your eighteen volt battery
pack may be triggering a low voltage kickout by making the set think it should
be getting twenty-eight volts.
I have no idea how multiple voltage units work, but I have had problems with
such devices when the voltages were between fourteen and twenty eight volts.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
________________________________________________________________________________
| From: | BobsV35B(at)aol.com |
| Subject: | Re: Old Bose Headsets Cutting Out |
In a message dated 5/9/2005 5:24:25 A.M. Central Standard Time,
psiegel(at)fuse.net writes:
I have a 1946 Aeronca Champ just out of restoration. I have the older style
portable Bose noise-cancelling headsets front and back. (The kind Bose no
longer supports other than to take as a trade-in for their new
headsets...don't get me started!) They can be powered by 12v-24v. I power them
with a
portable 10 x 1.2v 2400 mAh nicad pack.
Good Morning Once Again Paul,
I guess I goofed on when your problem was occurring. I had it in my mind
that you had the problem when hitting the set with eighteen volts. I see it is
the other way around. Twelve volts is awfully low for that set. I believe
you will have better luck if you be sure your battery pack is up closer to
fourteen volts when used with the Bose headsets.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Radio Noise Redux |
>
>
>Thanks OC....at this point all suggestions are most welcome. Even more
>importantly, I think I could install these things without making
>anything blow up! Thanks again.
>Bill Yamokoski
Bill, if running the radio on a separate battery made the noise
go away, then a 14v supply filter as suggested earlier is in order.
The noise abatement process can be tedious but the technique
is always the same. Isolate one potential propagation path
and explore its characteristics. All of the ideas/solutions
suggested have merit on some level but the vast majority
of noise issues involve conducted (+14v input), ground loop
(mic/headsets grounded in two or more places) and radiated
(noise comes in through antenna). Until you have eliminated
all of these as potential solutions, exploring all the
long-shots is likely to be fruitless. Each experiment takes
about the same amount of time to conduct so I'd make real
sure that you've covered the big-dogs first.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Airmaster AC200 manual switch? |
>
>
>Hello Bob
>
>I will be using a Airmaster prop on 914UL Rotax.
>The Airmaster Hub is called a AP332, it houses the electric motor and
>articulation
>mechanism while holding Warp drive Blades. You could use the AP332 like
>this and just have
>an adjustable pitch prop.
>
>Or you can add the AC200, which is a Constant speed black box controller.
>http://www.airmasterpropellers.com/
>Or can try http://www.airmasterpropellers.com/wa.asp?idWebPage=3474
>
>I am pretty certain your Schematic will work with just the AP332, if it
>were plumbed direct
>to the electric motor.
>
>When using the Constant speed black box controller, I downloaded as much
>info as i could,
>but it does not give enough detail as to what the switch does, perhaps it
>controls the
>motor direct somehow, or perhaps it is controlling some sort of circuit in
>the AP332 that
>is not direct to the motor.
I suspect this is the case. The switch currents will be quite
low and no boost relays will be necessary. However, it's possible
that their switching logic has some hidden caveats . . . I'd
recommend you talk to someone at the factory before you begin
any non-standard installation.
Bob . . .
________________________________________________________________________________
| From: | "colyncase on earthlink" <colyncase(at)earthlink.net> |
| Subject: | re: radio noise redux |
I just tuned into this thread so I may be missing some context. But here's one
thing to look into.
About a year ago I bought some brand new champion spark plug wires and started
hearing noise in the headset that did seem to change with the engine rpm.
I'll spare you all the blind alleys we went down. In the end, it turned out to
be that the crimp to the shielding on the spark plug leads, at the mag end,
was not adequately penetrating that cool new red spongy insulation. So I didn't
have the shield grounded. Squeezed it through with the pliers a little and
problem solved.
Colyn Case
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> Collins |
| Subject: | Re: OV damage to avionics: Dynon, Icom, |
Collins
Collins
>
>So will a couple of 18volt transorbs after a 5 or 7.5 amp fuse offer any
>real protection to an icom A200 I wonder? I guess I could set up a test
>to at least confirm that the fuse pops.
Keep in mind that an OV even is DYNAMIC. It's modeled by a constant
current source about 20% larger than alternator rating charging your
battery. The rate of voltage rise is not spectacular as long as there's
a good battery in the loop.
The 18V transorb, when asked to sink a 50A source will clamp
at some value well over 20v . . .
Now, if there's a battery on line, then it may be that you can
expect a fuse upstream of a transorb to open with sufficient
speed. I've not seen test data to support this notion so until
I can get onto a test stand and do my own measurements, I can't
recommend the fuse/transorb approach to transient protection.
It's been suggested that observance of operating parameters
suggested by DO-160/M-Std-704 are "dated" or some sort of
capitulation to outmoded technologies . . . but having lived
in this design environment for over 25 years, I can tell you
that it's not a simple task to put Band Aids on products not
designed to live in this world. It would have been much easier
to design transient immunity into the product than to add it
later.
Bob . . .
________________________________________________________________________________
| Subject: | Re: Radio Noise Redux |
| From: | "John Schroeder" <jschroeder(at)perigee.net> |
OC -
Where did you get these? I'm wondering if the ones they put on computer
cables would also work? If I remember correctly, they are also split.
Thanks,
John
> I eventually solved my problem by buying some split ferrite beads and
> installing them in several > different arbitrarily selected
> places in my comm system -- not very scientific. The noise went
> away.
--
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: OV damage to avionics: Dynon, Icom, Collins |
> Subject: AeroElectric-List message posted by:
...snip
> **Dynon EFIS D-10: all-in one EFIS unit that incorporates a color "glass"
display
> of all flight instruments. Dynon meets the electronics industry standard,
such
> as DO-160 and can handle input voltage of 10-30V and spikes of 60V for
very
> short period (20ms?). The main electronics are always protected, but if
the
> OV is extreme or duration too long, damage could occur to the unit.
However the
> damage would be limited and repair cost nominal.
It is remarkable that a little input protection can limit damage even from
lightning. Typically if a phone-line connected fax machine or modem catches
a lightning strike, you often find only a small amount of damage. Modern
devices often incorporate a gap in the PCB foil traces meant to arc to
ground in the event of a lightning strike.
> However he was steadfast that the radio must
> be off during start and the max volts was 15.8 volts. He did not see
anything
> in the circuit schematics that protected the main board from the power
source
> (aircraft power). Therefore he speculates that any over voltage or spike
would
> damage the radio? Obviously disappointed, I may check a little deeper.
Protecting the radio would cost maybe a buck. You wonder what they were
thinking........!
> **Collins TDR-950: Collins transponder sold to Meggitt/S-Tec back in the
late 90's.
> This design goes back a decade or two, and TDR-950s made by S-Tec are the
> same as units made by Collins. The TDR-950 does not have real over voltage
protection
> and could get fully toasted in a worst-case OV scenario. However it does
> have some sacrificial components that often fail first, such as a
capacitor,
> transistor and series relay, saving the main boards. However if it gets
past
> these first few items, it can extensively damage the transponder. The Gent
I
> talk to is a real technical "bench guy and seen 14V units connected to
28-32volt
> power. He suggest since it draws only 1.2 amps during TX a small 2 amp
fuse
> would protect it, since the unit will draw more amps with higher voltage,
as
> he stated it. Since I only have $300 into my TDR-950 I wont worry about it
too
> much, but may be a 1.5-2 amp fuse might be OK. Therefore if you have a
TDR-950
> turn it off for engine start and shutdown. S-Tec stopped producing them
several years
> ago but still supports them (because Piper makes them). Good value on the
used market.
Another dollar.......man o' man,,,,,,,
...snip...
> ALTERNATORS, INTERNAL VOLTAGE REGULATORS and OV
> I asked two large auto electrical overhaul shops about the ND alternators
and OV
> failures. None seen but the common failure is an OPEN field, ie quite
death
> but no OV.
George, I asked a couple places the same question and got the identical
answer--
They said they used to have OV runaways in the distant past...but nobody has
seem one in many years. Only "no-output" deaths.
...snip...
> (PS check the capability of this IC. Note the application and protections.
This
> chip is not associated with any specific alternator, just interesting.)
>
> http://www.freescale.com/files/analog/doc/data_sheet/MC33099FS.pdf
George, yes I thought so too. It took me 8 months to get some of these from
Digikey and I have some prototype regulators built. Note on the data sheet
that in the even of an OV problem the chip shut off a FET...politely
disconnecting the field lead. No crowbars here.
The helpful East Coast Alternator guy (John Anderika) says that many
internally regulated alternators in demanding applications are converted to
externally regulated devices...just so you can get to the field lead.
Paul Messinger wrote an article for Contact Magazine some years back about a
similar conversion.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
"Competition brings out the best in products and the worst in people."
- David Sarnoff
________________________________________________________________________________
| From: | "Jerry Grimmonpre" <jerry(at)mc.net> |
| Subject: | Save some cable ... maybe |
Electric Bob & listers:
This idea is offered-up as a possible way to save 3-4 feet of AWG-2 used for
the starter/alternator power supply for a Lycoming RV.
Strap the starter contactor to the side of the starter.
Connect AWG-2 from the hot side of the battery contactor direct to the input
side of the starter contactor. From the hot side of the starter contactor,
jump over to the alternator B out put with suitable sized AWG.
Connect a copper strap from the output of starter contactor to the input of
the starter solenoid.
Comments ...
Thanks and best regards ...
Jerry Grimmonpre
RV7A building my workshop
________________________________________________________________________________
| From: | "Leo Corbalis" <leocorbalis(at)sbcglobal.net> |
| Subject: | Re: Old Bose Headsets Cutting Out |
Try adding an additional cell in series with the n-c pack. Freshly charged
n-c cells put out about 1.4 volts. Measure the voltage when it happens. This
is a WAG : the louder noise in the front seat takes more power to cancel and
the headsets were designed to work on 14 volts which is normal in a working
system. 12 volts is not enough. Pre wire your measurements, One test per
flight.
Leo Corbalis
----- Original Message -----
From: <psiegel(at)fuse.net>
Subject: AeroElectric-List: Old Bose Headsets Cutting Out
>
> I have a 1946 Aeronca Champ just out of restoration. I have the older
> style portable Bose noise-cancelling headsets front and back. (The kind
> Bose no longer supports other than to take as a trade-in for their new
> headsets...don't get me started!) They can be powered by 12v-24v. I
> power them with a portable 10 x 1.2v 2400 mAh nicad pack.
>
> I also use this portable nicad pack as power for an A-22 Icom handheld
> radio which has its own 600 mAh internal nicad pack and a portable
> Sigtronics 2-person high noise intercom. The intercom also has an
> internal 9v "transistor radio" style back-up battery.
>
> My problem is that after about 10 minutes of flying the noise cancelling
> feature in the front (noisiest) seat kicks off. When I cycle the on-off
> switch it just comes back on for a few seconds.
>
> I swapped the headsets front and back and the problem persists. I tried
> different freshly cycled and fully charged nicad pack and the problem
> persists. I tried to power the front headset only with two 9v "transistor
> radio" batteries wired in series and the headsets work fine that way?
>
> I wonder why the front seat headset doesn't keep working with my shared 10
> cell nicad pack? Any suggestions? Anybody know how long the old Bose
> headset will operate on the two "transistor radio" style batteries?
>
> Please be patient with me as I am new to this list!
>
> Paul Siegel
>
>
>
________________________________________________________________________________
| From: | "Fergus Kyle" <VE3LVO(at)rac.ca> |
| Subject: | Flap root extension |
Cheers,
This message addresses itself to those who have gone before
[really, about everybody] in the construction - specifically the root
extension of the flaps to match the fuselage sides:
The instructions in my manual actually say to 'fit' the
extension foam forms to the root of the flaps. I took this to mean "cut to
permit the forms to slide into the root closeout to approximate its original
position" as an extension of the foam innards. If this were the case, they
would lose about 3/4" of width but would more accurately match the flap
itself. it would also mean quite a bit more addition of the forms to reach
the fuselage.
If you can warp your mind(s) back to that stage, can you
remember what you did, and why? I know I should tip to Andy or Nev but
presume them to be barely eyeballs above the time demands.
Your comments gleefully accepted.
Ferg
A064
Fuselage and wings out in the back lawn, dodging gulls and dead branches.
________________________________________________________________________________
| From: | Mickey Coggins <mick-matronics(at)rv8.ch> |
| Subject: | Re: OV damage to avionics: Dynon, Icom, Collins |
>
>
> Protecting the radio would cost maybe a buck. You wonder what they were
> thinking........!
>
Sounds like another nice product for you, Eric.
The Mini-Icom-Whack-OVP-Junior-Flux-Capacitor would
be a good name for it! :-)
--
Mickey Coggins
http://www.rv8.ch/
#82007 Wiring
________________________________________________________________________________
| From: | "Europa (Alfred Buess)" <ykibuess(at)bluewin.ch> |
| Subject: | Flap root extension |
Hi Ferg,
I just finished the filling job of my flap root extensions (and the
flaps themselves). This allows me to make a comment about the quality of
the root extensions of my conventional foam wings and flaps: I had made
foam forms, that plugged into the flap roots and made a smooth extension
of the flaps. This was achieved by sanding the oversized foam forms to
the exact form of the flaps. The layups of bid "thickened" the root area
slightly, but this was easily corrected with the filler. After filling
you cannot see where the main part of the flap ends and where the root
extension begins. Hope this helps a little bit to do that part of the
building job.
Regards,
Alfred
Alfred Buess
Laenggasse 81, CH-3052 Zollikofen, Switzerland
Tel.: +41 (0)31 911 63 32, Fax: +41 (0)31 911 56 32
E-Mail: ykibuess(at)bluewin.ch
Europa XS #097, Monowheel, Foam shortwing, Rotax 912S, Airmaster 332 CS
-----Ursprngliche Nachricht-----
Von: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] Im Auftrag von
Fergus Kyle
Gesendet: Montag, 9. Mai 2005 19:32
An: aeroelectric-list(at)matronics.com
Betreff: AeroElectric-List: Flap root extension
Cheers,
This message addresses itself to those who have gone before
[really, about everybody] in the construction - specifically the root
extension of the flaps to match the fuselage sides:
The instructions in my manual actually say to 'fit' the
extension foam forms to the root of the flaps. I took this to mean "cut
to
permit the forms to slide into the root closeout to approximate its
original
position" as an extension of the foam innards. If this were the case,
they
would lose about 3/4" of width but would more accurately match the flap
itself. it would also mean quite a bit more addition of the forms to
reach
the fuselage.
If you can warp your mind(s) back to that stage, can you
remember what you did, and why? I know I should tip to Andy or Nev but
presume them to be barely eyeballs above the time demands.
Your comments gleefully accepted.
Ferg
A064
Fuselage and wings out in the back lawn, dodging gulls and dead
branches.
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Save some cable ... maybe |
>
>Electric Bob & listers:
>This idea is offered-up as a possible way to save 3-4 feet of AWG-2 used for
>the starter/alternator power supply for a Lycoming RV.
>
>Strap the starter contactor to the side of the starter.
>
>Connect AWG-2 from the hot side of the battery contactor direct to the input
>side of the starter contactor. From the hot side of the starter contactor,
>jump over to the alternator B out put with suitable sized AWG.
>
>Connect a copper strap from the output of starter contactor to the input of
>the starter solenoid.
Unless your battery is located in the tail, 4AWG is most
adequate . . . in fact, a number of builders have used 2AWG
only for the long run from battery contactor to starter contactor
and 4AWG for all other segments. If your battery is up front,
then 4AWG is fine throughout the chrarging/cranking path.
The wire is much easier to work with than adding labor to
fabricate a suitable hardware for mounting starter contactor
on the starter.
What you describe will function electrically. If that system
is attractive to you, consider using the built-in starter contactor
that comes with most modern starters. Use the boost relay
circuit shown in Figure Z-22. Then jumper alternator b-lead
to the starter contactor hot terminal using a Maxi-Fuse HHX inline
holder. See page 13 of
of http://www.bussmann.com/shared/library/catalogs/Buss_Auto-Fuse_Cat.pdf
Maxi fuses can be found on page 3. Use MAX60 fuse on 40A alternator,
MAX80 on a 60A alternator. Eliminate alternator loadmeter feature.
The boost relay can mount on firewall. No new hardware bolted
to engine.
Bob . . .
________________________________________________________________________________
| Subject: | Flap root extension |
| From: | "David Glauser" <david.glauser(at)xpsystems.com> |
Uh, Ferg - I think you meant this to go to the Europa list, not 'lectric
Bob's, right?
dg
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Fergus Kyle
Subject: AeroElectric-List: Flap root extension
Cheers,
This message addresses itself to those who have gone before
[really, about everybody] in the construction - specifically the root
extension of the flaps to match the fuselage sides:
The instructions in my manual actually say to 'fit' the
extension foam forms to the root of the flaps. I took this to mean "cut
to permit the forms to slide into the root closeout to approximate its
original position" as an extension of the foam innards. If this were the
case, they would lose about 3/4" of width but would more accurately
match the flap itself. it would also mean quite a bit more addition of
the forms to reach the fuselage.
If you can warp your mind(s) back to that stage, can you
remember what you did, and why? I know I should tip to Andy or Nev but
presume them to be barely eyeballs above the time demands.
Your comments gleefully accepted.
Ferg
A064
Fuselage and wings out in the back lawn, dodging gulls and dead
branches.
________________________________________________________________________________
| From: | "Giffen A Marr" <gamarr(at)charter.net> |
Bob
Am I confused or is there a typo in the Z-28 figure on the right hand side.
The Aux Bat and Main Bat are both shown connected to the right ignition. Is
this right or am I missing something?
Giff Marr
LIVP/20B 35%
________________________________________________________________________________
| From: | rwtalbot(at)purephotos.com.au |
| Subject: | Re: OV damage to avionics: Dynon, Icom, Collins |
>
>
>> Subject: AeroElectric-List message posted by:
>
>
> Protecting the radio would cost maybe a buck. You wonder what they were
> thinking........!
Eric,
You mean other than - $ervices revenue, $ervices revenue, $ervices
revenue, $ervices revenue, $$$ $$$ ?
Richard
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
April 26, 2005 - May 10, 2005
AeroElectric-Archive.digest.vol-ej