Today's Message Index:
----------------------
1. 05:08 AM - Running avionics on power supply (Ralph E. Capen)
2. 05:54 AM - Re: Running avionics on power supply (JOHN TIPTON)
3. 06:56 AM - Tefzel cables and d-sub connectors (Terry Phillips)
4. 07:05 AM - Battery Replacement STC ()
5. 08:10 AM - Re: Tefzel cables and d-sub connectors (Ben Westfall)
6. 09:46 AM - Re: Location of battery bus ()
7. 10:05 AM - Re: Running avionics on power supply (mwcreek@frontiernet.net)
8. 10:49 AM - Re: Running avionics on power supply (Ralph E. Capen)
9. 12:11 PM - Re: Running avionics on power supply (mwcreek@frontiernet.net)
10. 03:15 PM - Re: Re: Pullable 60 Amp Breaker (Robert L. Nuckolls, III)
11. 03:52 PM - Re: Re: Pullable 60 Amp Breaker (Robert L. Nuckolls, III)
12. 04:02 PM - Re: Question about Relays/Switches (Robert L. Nuckolls, III)
13. 04:05 PM - Re: Radio interlock (Robert L. Nuckolls, III)
14. 04:06 PM - Re: Battery Replacement STC (Robert L. Nuckolls, III)
15. 04:45 PM - Re: Location of battery bus ()
16. 04:46 PM - Re: Tefzel cables and d-sub connectors (The Kuffels)
17. 05:46 PM - Re: Re: Pullable 60 Amp Breaker (Marvin Dorris Jr)
18. 07:44 PM - Re: Tefzel cables and d-sub connectors (Robert L. Nuckolls, III)
19. 08:15 PM - Re: Location of battery bus (Bill Schlatterer)
20. 08:47 PM - Re: Re: Pullable 60 Amp Breaker (Robert L. Nuckolls, III)
21. 08:58 PM - Re: Running avionics on power supply (Robert L. Nuckolls, III)
Message 1
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| Subject: | Running avionics on power supply |
No replies to my initial post, so trying again....
Should there be any issues in running my electrical system with a power supply
instead of the alternater/engine running? I have a battery in the circuit (PC680).
Do I need to connect the power supply directly to the battery or can I hook it
to my shunt to simulate the power coming from the alternator?
Just want to make sure that I don't fry anything.....
Ralph Capen
Message 2
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| Subject: | Re: Running avionics on power supply |
Likewise: I have a CB power supply (13.8v 3amp) which I thought of using to
power up the system - to the vacant battery terminal or where?
John
----- Original Message -----
From: "Ralph E. Capen" <recapen@earthlink.net>
<avionics-list@matronics.com>
Sent: Wednesday, November 21, 2007 12:56 PM
Subject: AeroElectric-List: Running avionics on power supply
> <recapen@earthlink.net>
>
> No replies to my initial post, so trying again....
>
> Should there be any issues in running my electrical system with a power
> supply instead of the alternater/engine running? I have a battery in the
> circuit (PC680).
> Do I need to connect the power supply directly to the battery or can I
> hook it to my shunt to simulate the power coming from the alternator?
>
> Just want to make sure that I don't fry anything.....
>
> Ralph Capen
>
>
>
Message 3
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| Subject: | Tefzel cables and d-sub connectors |
I am have reached the point in my building where I have to address some electrical
design issues. I need to install the servo for the R.A. Allen electric elevator
trim tab. The servo has 5 leads, and is supplied with a length of 5-conductor
Belden 8445 cable to connect to the controls in the cockpit. A check on
the Internet shows that this cable is PVC insulated with 5 22AWG wires. I have
a several questions.
1. I was planning to use Tefzel insulated cable as much as possible. Is it worthwhile
to replace R.A. Allen's PVC insulated cable with Tefzel insulated cable?
2. For this application cable would be better than 5 individual wires, because
the wires must pass outside the skin from the elevator to the fuselage. After
looking around on the Internet, I was unable to find a 5-conductor cable with
Tefzel wire insulation and a Tefzel jacket. I did find a company, TPC Wire,
http://www.tpcwire.com/tpc/pdf/03_TrOxCable_6.pdf,
that sells 100 ft lengths of shielded cable with Tefzel wire insulation and a polyurethane
exterior cover that should work (part no. 61506). They don't have
5 conductor cable, but the 6 conductor cable would not be much heavier. Does such
a cable look like a reasonable substitute? Are there other sources for Tefzel
insulated cable that I should consider?
3. The servo instructions suggest soldering the cable conductors to the servo leads
and wrapping the joints with electrical tape. I was originally planning to
use butt splice crimp connectors instead of soldering. I'm now considering using
a 9 conductor d-sub plug. Are the d-sub plugs a good choice for a remote
location, like the elevator?
4. If one uses a d-sub, should the plug itself be secured to the elevator (how?)
or would cable ties or an adel clamps on the cable provide adequate support.
5. Also, since TPC Wire has a $100 minumum order, it behooves me to buy cable for
other uses in the airplane in this one order. E.g., power for the nav lights,
headlights, etc. One use that I'm considering is to buy some 24 conductor cable
to pass through the firewall to carry engine instrument signals. Which brings
me back to the d-sub connectors. Would d-subs be reasonable replacement for
the terminal strips that I have seen used to connect engine instruments to
wires passing through the firewall? Can d-subs handle engine compartment temperatures?
Will thermocouple leads crimped into d-sub pins work OK? Are d-subs robust
enough to endure the correction of wiring goofs?
--------
Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Rudder done--finally; working on the stab
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=147691#147691
Message 4
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| Subject: | Battery Replacement STC |
11/21/2007
Hello Bob Nuckolls and other list experts, My friend wants to replace the
two conventional 12 volt lead acid Gill batteries in his 24 volt system
Beech Sierra with two 12 volt Concorde recombinant gas batteries.
I can find tables that shows the correct batteries, but also show that an
STC (held by Wilco) is involved:
http://www.concordebattery.com/aag3.php?id=2775
http://www.aircraftspruce.com/catalog/pdf/finalfaapma.pdf (see page 8)
What is the proper procedure / FAA required paperwork / permission from STC
holder, to make this battery switch?
Thanks.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
Message 5
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| Subject: | Tefzel cables and d-sub connectors |
Terry,
Bob has a decent webpage that covers your question #3 below.
http://www.aeroelectric.com/articles/macservo/macservo.html
There is another good article on "Soldering D-Sub Connectors" that can be
found here:
http://www.aeroelectric.com/articles/dsubs/d_solder.html
-Ben Westfall
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Terry
Phillips
Sent: Wednesday, November 21, 2007 6:55 AM
Subject: AeroElectric-List: Tefzel cables and d-sub connectors
I am have reached the point in my building where I have to address some
electrical design issues. I need to install the servo for the R.A. Allen
electric elevator trim tab. The servo has 5 leads, and is supplied with a
length of 5-conductor Belden 8445 cable to connect to the controls in the
cockpit. A check on the Internet shows that this cable is PVC insulated with
5 22AWG wires. I have a several questions.
1. I was planning to use Tefzel insulated cable as much as possible. Is it
worthwhile to replace R.A. Allen's PVC insulated cable with Tefzel
insulated cable?
2. For this application cable would be better than 5 individual wires,
because the wires must pass outside the skin from the elevator to the
fuselage. After looking around on the Internet, I was unable to find a
5-conductor cable with Tefzel wire insulation and a Tefzel jacket. I did
find a company, TPC Wire,
http://www.tpcwire.com/tpc/pdf/03_TrOxCable_6.pdf,
that sells 100 ft lengths of shielded cable with Tefzel wire insulation and
a polyurethane exterior cover that should work (part no. 61506). They don't
have 5 conductor cable, but the 6 conductor cable would not be much heavier.
Does such a cable look like a reasonable substitute? Are there other sources
for Tefzel insulated cable that I should consider?
3. The servo instructions suggest soldering the cable conductors to the
servo leads and wrapping the joints with electrical tape. I was originally
planning to use butt splice crimp connectors instead of soldering. I'm now
considering using a 9 conductor d-sub plug. Are the d-sub plugs a good
choice for a remote location, like the elevator?
4. If one uses a d-sub, should the plug itself be secured to the elevator
(how?) or would cable ties or an adel clamps on the cable provide adequate
support.
5. Also, since TPC Wire has a $100 minumum order, it behooves me to buy
cable for other uses in the airplane in this one order. E.g., power for the
nav lights, headlights, etc. One use that I'm considering is to buy some 24
conductor cable to pass through the firewall to carry engine instrument
signals. Which brings me back to the d-sub connectors. Would d-subs be
reasonable replacement for the terminal strips that I have seen used to
connect engine instruments to wires passing through the firewall? Can d-subs
handle engine compartment temperatures? Will thermocouple leads crimped into
d-sub pins work OK? Are d-subs robust enough to endure the correction of
wiring goofs?
--------
Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Rudder done--finally; working on the
stab
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=147691#147691
Message 6
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| Subject: | Location of battery bus |
I am at the same decision point. There seems to be a funny rumor out
there that the battery buss needs to be sitting on top of the battery.
Voltage drop for 12-14 volts may be an issue over 12' but not over 12".
I will mount them inside where it is clean and dry but still close to
the firewall.
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bill
Schlatterer
Sent: Wednesday, November 21, 2007 12:21 AM
Subject: RE: AeroElectric-List: Location of battery bus
Bevan, this is what I did on my 7a for block locations. Small
Tab forest on FW side to large forest on cabin side. Fuse blocks on the
inside are on a swing down tray. Ran the battery lead to the always hot
bus to a fuse slot which really protects the wrong end of the wire but
it seemed better than nothing (maybe a fusible link on the battery end
would be better). Wire is about 14" from Battery to bus as I remember
it but not likely to have a problem.
Bill S
7a
________________________________
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of B
Tomm
Sent: Tuesday, November 20, 2007 3:28 AM
To: aeroelectric-list@matronics.com
Subject: AeroElectric-List: Location of battery bus
Good morning Bob,
Considering Z-13/20 architecture in an RV7A. The Vans
recommended position for the battery is on the firewall in the engine
compartment which I agree with. That being said, the contactors would
be located nearby. Would it follow that the battery bus should also be
located on the engine side of the firewall and if so, would it be
appropriate to use a fuse block style as we've come to appreciate? In
other words, would the fuse block style and associated faston terminals
stand up in the FF environment? I would prefer to see the fuses inside
the cockpit just aft of the firewall (cleaner environment), but to get
to here there would be a little more than 6 inches of unprotected wire.
Thanks again.
Bevan
href="http://www.matronics.com/contribution">http://www.matronics.com/c
h
ref="http://www.matronics.com/Navigator?AeroElectric-List">http://www.m
a
tronics.com/Navigator?AeroElectric-List
href="http://forums.matronics.com">http://forums.matronics.com
Message 7
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| Subject: | Re: Running avionics on power supply |
FWIW,
I've been powering my pannel from a PC680 with a battery charger
connected to it and have not had any problems. The charger output
voltage was fluctuating (or I had bad connections) when I powered
directly from it so using the battery as a sink made it work just
fine. The follwing equipment is being powered this way:
GRT Sport
SL30
GTX327
GRT EIS
TT AP
PSE 3000
Hope this helps,
Mike
Quoting JOHN TIPTON <jmtipton@btopenworld.com>:
> <jmtipton@btopenworld.com>
>
> Likewise: I have a CB power supply (13.8v 3amp) which I thought of
> using to power up the system - to the vacant battery terminal or where?
>
> John
>
> ----- Original Message ----- From: "Ralph E. Capen" <recapen@earthlink.net>
> To: "Aeroelectric-list" <aeroelectric-list@matronics.com>; "Avionics
> List" <avionics-list@matronics.com>
> Sent: Wednesday, November 21, 2007 12:56 PM
> Subject: AeroElectric-List: Running avionics on power supply
>
>
>> <recapen@earthlink.net>
>>
>> No replies to my initial post, so trying again....
>>
>> Should there be any issues in running my electrical system with a
>> power supply instead of the alternater/engine running? I have a
>> battery in the circuit (PC680).
>> Do I need to connect the power supply directly to the battery or
>> can I hook it to my shunt to simulate the power coming from the
>> alternator?
>>
>> Just want to make sure that I don't fry anything.....
>>
>> Ralph Capen
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 8
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| Subject: | Re: Running avionics on power supply |
Your charger is connected directly to the battery?
-----Original Message-----
>From: "mwcreek@frontiernet.net" <mwcreek@frontiernet.net>
>Sent: Nov 21, 2007 1:01 PM
>To: aeroelectric-list@matronics.com
>Subject: Re: AeroElectric-List: Running avionics on power supply
>
>
>FWIW,
>
>I've been powering my pannel from a PC680 with a battery charger
>connected to it and have not had any problems. The charger output
>voltage was fluctuating (or I had bad connections) when I powered
>directly from it so using the battery as a sink made it work just
>fine. The follwing equipment is being powered this way:
>
>GRT Sport
>SL30
>GTX327
>GRT EIS
>TT AP
>PSE 3000
>
>Hope this helps,
>Mike
>
>Quoting JOHN TIPTON <jmtipton@btopenworld.com>:
>
>> <jmtipton@btopenworld.com>
>>
>> Likewise: I have a CB power supply (13.8v 3amp) which I thought of
>> using to power up the system - to the vacant battery terminal or where?
>>
>> John
>>
>> ----- Original Message ----- From: "Ralph E. Capen" <recapen@earthlink.net>
>> To: "Aeroelectric-list" <aeroelectric-list@matronics.com>; "Avionics
>> List" <avionics-list@matronics.com>
>> Sent: Wednesday, November 21, 2007 12:56 PM
>> Subject: AeroElectric-List: Running avionics on power supply
>>
>>
>>> <recapen@earthlink.net>
>>>
>>> No replies to my initial post, so trying again....
>>>
>>> Should there be any issues in running my electrical system with a
>>> power supply instead of the alternater/engine running? I have a
>>> battery in the circuit (PC680).
>>> Do I need to connect the power supply directly to the battery or
>>> can I hook it to my shunt to simulate the power coming from the
>>> alternator?
>>>
>>> Just want to make sure that I don't fry anything.....
>>>
>>> Ralph Capen
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>
>
Message 9
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| Subject: | Re: Running avionics on power supply |
yes, the battery charger is connected directly to the battery.
Quoting "Ralph E. Capen" <recapen@earthlink.net>:
> <recapen@earthlink.net>
>
> Your charger is connected directly to the battery?
>
> -----Original Message-----
>> From: "mwcreek@frontiernet.net" <mwcreek@frontiernet.net>
>> Sent: Nov 21, 2007 1:01 PM
>> To: aeroelectric-list@matronics.com
>> Subject: Re: AeroElectric-List: Running avionics on power supply
>>
>> <mwcreek@frontiernet.net>
>>
>> FWIW,
>>
>> I've been powering my pannel from a PC680 with a battery charger
>> connected to it and have not had any problems. The charger output
>> voltage was fluctuating (or I had bad connections) when I powered
>> directly from it so using the battery as a sink made it work just
>> fine. The follwing equipment is being powered this way:
>>
>> GRT Sport
>> SL30
>> GTX327
>> GRT EIS
>> TT AP
>> PSE 3000
>>
>> Hope this helps,
>> Mike
>>
>> Quoting JOHN TIPTON <jmtipton@btopenworld.com>:
>>
>>> <jmtipton@btopenworld.com>
>>>
>>> Likewise: I have a CB power supply (13.8v 3amp) which I thought of
>>> using to power up the system - to the vacant battery terminal or where?
>>>
>>> John
>>>
>>> ----- Original Message ----- From: "Ralph E. Capen" <recapen@earthlink.net>
>>> To: "Aeroelectric-list" <aeroelectric-list@matronics.com>; "Avionics
>>> List" <avionics-list@matronics.com>
>>> Sent: Wednesday, November 21, 2007 12:56 PM
>>> Subject: AeroElectric-List: Running avionics on power supply
>>>
>>>
>>>> <recapen@earthlink.net>
>>>>
>>>> No replies to my initial post, so trying again....
>>>>
>>>> Should there be any issues in running my electrical system with a
>>>> power supply instead of the alternater/engine running? I have a
>>>> battery in the circuit (PC680).
>>>> Do I need to connect the power supply directly to the battery or
>>>> can I hook it to my shunt to simulate the power coming from the
>>>> alternator?
>>>>
>>>> Just want to make sure that I don't fry anything.....
>>>>
>>>> Ralph Capen
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 10
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| Subject: | Re: RE: Pullable 60 Amp Breaker |
From: <gmcjetpilot@yahoo.com>
Subject: AeroElectric-List: RE: Pullable 60 Amp Breaker
>
> >First, know that designers of upper-end production aircraft
> >have made a effort to get high-current, noise-carrying
> >conductors off the panel.
>
>Never heard noise in my plane with B-lead CB in panel.
>I would just say prove it. Modern internally regulated alternators
>are not noisy so it's a moot point. Old Gen from days gone by, yes
>noisy.
George, this has nothing to do with the style of
regulator. 3-phase rectified AC has a 5% built-in ripple
component that is a physical artifact of the product.
I've encountered magnetically coupled noises in both
automobiles and aircraft. So your statement about "modern
internally regulated alternators not being noisy" is
demonstrably in error and your admonition to "prove it"
is a manifestation of your proven history of inability
or unwillingness to carry on discussions based on
physics and simple-ideas.
I've troubleshot and fixed a number of magnetically
coupled alternator whine problems on aircraft and once
in my own automobile. It's doubtful that any demonstration
would be sufficient "proof" to make this phenomenon
real and significant in your limited understanding.
Alternators are much more noisy than generators.
> >Third, it has been suggested that a breaker might serve
> >as the last-ditch means by which a pilot can bring a runaway
> >alternator to heel . . . or at least disconnect it from the
> >system. This logic is flawed for several reasons: (1) breakers
> >are designed to disconnect hard downstream faults in a system
> >where the voltage are on the order of 32 volts or less. (2)
> >A runaway alternator is capable of raising the b-lead terminal
> >to hundreds of volts in milliseconds where it is NOT reasonable
> >to expect the breaker to also serve as a SWITCH for reliable
> >disconnect of the offending alternator. Any attempt to use
> >a breaker (particularly a miniature one with plastic housing!)
> >or this purpose is to flirt with probability of cockpit fire
> >and much smoke.
>
>With all due respect I think your logic is flawed. It may fit for external
>regulated alternators but not for internally regulated ones.
It matters not what style of alternator is being
considered, any alternator running self-excited by
a field voltage which is a product of it's own output
is capable of well over 100 volts of output. See:
http://aeroelectric.com/articles/When_is_110V_not_Over_Voltage.pdf
>
>A CB is RATED to disconnect at 32 volts many many times, however
>it can handle much more. No I don't have an absolute number but
>when most 12 volt alternators with a so called over voltage rarely
>exceeds 17 v much less 32 v, your point is moot, 32v good enough.
Yes, the runaway alternators that were NOT putting out
hundreds of volts were being loaded by a battery that
was dutifully sacrificing itself by accepting what the
alternator could deliver due to its inherent current
limiting.
But the very act of opening the b-lead on a runaway
alternator disconnects the battery and all other parts
of the ship's systems. As soon as the contacts of the
'switch' open, the alternator becomes unrestrained and
b-lead voltage will rise rapidly to values much greater
than the 32-volt rating of the breaker. Once you strike
the arc between the opening contacts, one has 100+
volts at 40-60 amps (4,000+ watts) of potential power
being dumped into the fire. This would probably be
contained by an all-metal enclosure like:
http://www.aeroelectric.com/Pictures/Contactors/s701-1.jpg
but enclosures like this . . .
http://www.aeroelectric.com/Pictures/Contactors/6041_Contactor.jpg
. . . have proven incapable of containing such fires
http://www.aeroelectric.com/Pictures/Failures/6041_Contactor_Failure.jpg
>
>When you say 100's of VOLTS and Cockpit FIRE, it's fear mongering
>not based on facts. Science and engineering are based on facts not
>emotional reasons. CB catch on fire? Really? OK, prove it.
It is an absolute certainty that an enclosure like this
http://www.aeroelectric.com/Pictures/Breakers/circuitbreakers.jpg
will not contain such fires either.
>
>Small 40 / 60 amp alternators are not pumping 100's of volts or amps.
>Internally regulated alternators typically go to 16 or 17 volts, if
>regulation fails, easily controlled by a CB. Yes there may have
>been one "screw lose" case where voltage was truly out of control,
>but it's rare, and the voltage was undetermined. I doubt it got to
>over 32 volts.
As soon as the runaway alternator is disconnected from
the system by pulling a breaker, the battery is relieved
of sacrificial duties and the voltage at the alternator's
b-lead will rise rapidly and to magnitudes previously cited. . .
the Mother of All Load Dumps.
>
>Also an ANL fuse will not blow with 100's of volts, it's a current
>device. If you want to wire your airplane like a Toyota with fuses, fine,
>but there is no need to make stuff up against CB's in the panel.
Fuses are not expected to protect against over-voltage events
but over-current events. Know that a runaway alternator has
NEVER put out more current that what's established by the
physics of it's magnetics. I.e, not enough to open the
b-lead protection irrespective of it's design (assuming
it is sized for sufficient headroom to avoid nuisance
tripping). Nonetheless, bus voltages are carried upward
to many times greater than normal bus voltage unless
some well considered means for stopping it has been included
in the design.
> >Finally, know that a 60A breaker on a 60A alternator is
> >DESIGNED to nuisance trip. The b-lead protection on an alternator
> >should stay closed at current levels perhaps 20% higher than
> >the nameplate rating of the alternator. The GA spam-can community
> >really blew it when 60A b-lead breakers were installed in 100,000+
> >aircraft with 60A alternators.
>
>Easily solved by sizing the CB properly. I guess they don't have
>smart people working for the GA spam-can community. Frankly CB's
>can take slight overloads for a period of time with out a trip. Again
>moot point Bob, if the alternator can only put out 45 amps.
That's what I said. The 60A breaker is too small for
being used with a 60A alternator. Yes, MOST nuisance
tripping is avoided by the noteworthy time delays
inherent in the design of CBs . . . but the majority
of nuisance trips of breakers in light aircraft are
the 60A b-lead breaker tied to a 60A alternator.
Your off-hand comment about the intelligence of folks
working in GA is uncalled for and yet another manifestation
of your long and oft demonstrated history of belligerent,
ill-informed, nay ignorant participation on this List.
There are MANY folks within GA that would very much
like to rectify the condition cited . . . but it's never
bubbled to the top-ten-problems list with an airframe OEM and
the FAA makes it insanely $difficult$ to make even the
simplest changes. Hence, this marginal design has
endured for decades more out of resignation to the
authority of a higher power than of ignorance or apathy.
> >In my humble opinion, ignoring a lot of experience and
> >thoughtful reasoning suggesting that panel a mounted, b-lead
> >breaker is not the best-we-know-how-to-do.
> >Bob . . .
>
>What?
>
>Fuses are fine. Buth with (stock) internal regulation the CB is a good
>reason to use a B-lead CB. Other engineers have worked on this
>Bob. The pull-able CB for the B-lead is specified. It's irresponsible of
>you to be so stubborn and opinionated, making ONE blanked edict
>that one size fits all. Fuses are not a BE ALL solution for every
>application. Follow the manufactures recommendation!
This isn't a fuses/breakers discussion, it's
an examination of the physics which govern assembly
of some exceedingly simple ideas into recipes for
success with an acknowledgment of hazards which
should be considered as part of a thoughtful design.
>
>In my humble opinion, I disagree with Bob with my thoughtful reasoning
>and facts. I don't care what you use but know why you are using it. I
>don't believe you will have noise or won't be able to disconnect the
>b-lead manually if you want to. When people talk 100's of volts & fire
>they are exaggerating in non-scientific emotional arguments, not
>engineering. Have Bob prove these are real problems. I could come
>up with lots of NIT PICK reasons a fuse really is a poor choice.
George, you have been politely requested to keep
your comments on this topic to yourself . . . they've
been read many times for years on this List and debunked
as recorded and published at:
http://www.aeroelectric.com/articles/gmcjetpilot.html
http://aeroelectric.com/articles/The_Truth_about_Crowbar_OV_Protection.pdf
You have designed nothing, fixed nothing, contributed
nothing to the understanding of physics, serviced no
customers, taught no classes, or offered a 100% satisfaction
assured warranty for your products. Yet you persist
in lurking at the edges of a sandbox not of your
construction to throw rocks and mud while hiding behind
a pseudonym decorated with much alphabet soup of
self proclaimed titles/accolades. You claim superior
engineering insight while never having demonstrated
it with useful work-product.
I've demonstrated/experienced/explained every assertion
I've ever made based on my hands-on experiences with these
systems since I did my first OV relay design for Cessna
Aircraft in 1975. Your belittling diatribes and circular
arguments contribute nothing to the advancement of
our science, understanding or art and yet you deign to
call me a liar. Your brand of 'science' is not welcome
in this classroom. You sir are the secretive, fraudulent
participant in these discussions and I will ask you
politely for the third or forth time, please go away.
Bob . . .
(---------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
(---------------------------------------)
Message 11
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| Subject: | RE: Pullable 60 Amp Breaker |
At 04:12 PM 11/20/2007 -0600, you wrote:
>Why would anyone want to reset a tripped 60A breaker in flight ?
>
>If you want to disable the alternator than switching off the alternator
>field would generate a lot less transients that components have to deal with.
Yes, you'll have to research this topic in the
archives a bit. It's not about whether or not
one should 'reset' a tripped breaker but one
of selecting design goals. I.e, is it (1)
reasonable to assume an alternator with a "broken"
internal regulator can be depended upon to
remain at or below 17 volts and (2)
depend on a panel mounted b-lead breaker
to disconnect said alternator from the bus
after (3) the pilot becomes aware of the OV
condition.
It has been suggested that this design
goal is a suitable alternative to architectures
and goals embraced by the vast majority
of the TC aviation community.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 12
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| Subject: | Question about Relays/Switches |
At 03:58 PM 11/20/2007 -0700, you wrote:
>
>Bob,
>
>Thank you much for the information. Those look like the regular vanilla
>automotive relays that I have used for years in cars.
>
>Are those suitable for our applications? I am just not certain I want to
>entrust tens of thousands of dollars of my airplane and its ESSENTIAL BUS to
>a $9 relay.
Sure, why not? What can a relay DO that puts the
equipment at risk? In this case, it's used in but
on of two power paths which should share no common
hardware. So if one path is down it is (1) preflight
detectable, (2) does not cause an immediate hazard
to flight for in flight failure.
>If that's the case, I could use a SPDT continuous duty relay (like a Marine
>application) found here -
>http://www.ebasicpower.com/pc/ARCR038/ALLRELAYS/Relay%2C+12V%2C+85+Amp%2C+S.
>P.D.T. to power my E-Bus from my Main Battery.
How big are the loads on your e-bus?
>I could even get radical and have the Main Battery power my E-Bus when the
>coil is energized and have it switch to my Aux Battery when coil is not
>energized. Since there is already a SPST Continuous Duty Relay upstream of
>both my main battery and aux battery, powering down the plane shouldn't be a
>problem.
>Thoughts?
Methinks thou worriest too much. First, assume
that ANY piece of hardware you incorporate into
your system can and at some time will fail in
flight. The proceed to architecture your system
with the following in mind:
Nuckolls' first law of airplane systems design sez: "Things
break"
The second: "Systems shall be designed so that when things
break, no immediate hazard is created."
The third: "Things needed for comfortable termination of
flight require backup or special consideration to insure
operation and availability"
The forth: "Upgrading the quality, reliability, longevity, or
capability of a part shall be because you're tired of replacing
it or want some new feature, not because it damned near got
you killed."
If you've done your homework, then no single
failure of a component will put the flight
at risk for unhappy termination. The thought
process goes toward designing for failure
tolerance as opposed to seeking components
that will never fail.
Bob . . .
Message 13
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| Subject: | Re: Radio interlock |
At 10:23 PM 11/20/2007 -0800, you wrote:
>
>Bob Archer used to sell (and probably still does) an antenna switch which
>allows for reception on two radios simultaneously and locks out the
>non-transmitting radio (whichever one it is) upon closing the PTT of either.
Now, THAT'S a different set of circumstances and design
goals. Here there is acknowledgment of risk to a receiver
from a transmitter's output for DIRECTLY paralleled transceivers
on a single antenna. This is a very useful alternative to the
dual antenna installation where it's acceptable to have
the non-transmitting transceiver become unusable while
talking on the other.
Bob . . .
Message 14
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| Subject: | Re: Battery Replacement STC |
At 09:55 AM 11/21/2007 -0500, you wrote:
>
>11/21/2007
>
>Hello Bob Nuckolls and other list experts, My friend wants to replace the
>two conventional 12 volt lead acid Gill batteries in his 24 volt system
>Beech Sierra with two 12 volt Concorde recombinant gas batteries.
>
>I can find tables that shows the correct batteries, but also show that an
>STC (held by Wilco) is involved:
>
>http://www.concordebattery.com/aag3.php?id=2775
>
>http://www.aircraftspruce.com/catalog/pdf/finalfaapma.pdf (see page 8)
>
>What is the proper procedure / FAA required paperwork / permission from
>STC holder, to make this battery switch?
Call Wilco and I'm sure they'll be able to cite
the process down to the last signature on your
ship's paperwork. Generally speaking, the battery
STC's are probably the simplest of "mods" to accomplish
on a TC aircraft. I crafted a couple of STCs for B&C
some years ago to put Genesis RG batteries (Hawker)
on the smaller Cessnas and Pipers. When you buy
the battery + STC it will come with the proper permission
documents.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 15
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| Subject: | Location of battery bus |
Great job Bill. Your work looks good.
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bill
Schlatterer
Sent: Wednesday, November 21, 2007 12:21 AM
To: aeroelectric-list@matronics.com
Subject: RE: AeroElectric-List: Location of battery bus
Bevan, this is what I did on my 7a for block locations. Small
Tab forest on FW side to large forest on cabin side. Fuse blocks on the
inside are on a swing down tray. Ran the battery lead to the always hot
bus to a fuse slot which really protects the wrong end of the wire but
it seemed better than nothing (maybe a fusible link on the battery end
would be better). Wire is about 14" from Battery to bus as I remember
it but not likely to have a problem.
Bill S
7a
________________________________
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of B
Tomm
Sent: Tuesday, November 20, 2007 3:28 AM
To: aeroelectric-list@matronics.com
Subject: AeroElectric-List: Location of battery bus
Good morning Bob,
Considering Z-13/20 architecture in an RV7A. The Vans
recommended position for the battery is on the firewall in the engine
compartment which I agree with. That being said, the contactors would
be located nearby. Would it follow that the battery bus should also be
located on the engine side of the firewall and if so, would it be
appropriate to use a fuse block style as we've come to appreciate? In
other words, would the fuse block style and associated faston terminals
stand up in the FF environment? I would prefer to see the fuses inside
the cockpit just aft of the firewall (cleaner environment), but to get
to here there would be a little more than 6 inches of unprotected wire.
Thanks again.
Bevan
href="http://www.matronics.com/contribution">http://www.matronics.com/c
h
ref="http://www.matronics.com/Navigator?AeroElectric-List">http://www.m
a
tronics.com/Navigator?AeroElectric-List
href="http://forums.matronics.com">http://forums.matronics.com
Message 16
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| Subject: | Re: Tefzel cables and d-sub connectors |
Terry,
I have a small amount of Belden 89503 plenum cable. 3-pair
twisted with overall foil shield & drain wire, 24 AWG and Teflon
FEP insulation. Flame and smoke resistant, good to 200 degrees C.
If this is acceptable for your use let me know the length from
your trim motor to your trim switch. I'll add 5 feet, cut off a
hunk and drop it off in Corvallis. I am driving through Hamilton
Wed Dec 5 and coming back the next day.
do not archive
Tom Kuffel
Whitefish, MT
Message 17
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| Subject: | RE: Pullable 60 Amp Breaker |
With several hundred, uh thousands (they become blurred and seemingly insig
nificant) of flight hours I now attempt a life-long goal of building my ow
n airplane. My self-professed weakness is wiring, electronics and electric
ity in general. Thus, my reason for joining this forum. I read every post
with an open mind and hopefully add to my limited understanding of the tra
veling electron.
In following this thread of "Pullable 60 Amp Breaker" I am reminded of some
thing I learned a long time ago. The only difference between a jet pilot a
nd a jet engine is the fact that a jet engine stops whining when you shut i
t down.
Happy Thanksgiving & Best Regards to all,
Marvin
e: Wed, 21 Nov 2007 17:08:17 -0600> To: aeroelectric-list@matronics.com> Fr
om: nuckolls.bob@cox.net> Subject: Re: AeroElectric-List: RE: Pullable 60 A
III" <nuckolls.bob@cox.net>> > > > > Date: Tue, 20 Nov 2007 13:23:04 -0800
(PST)> From: <gmcjetpilot@yahoo.com>> Subject: AeroElectric-List: RE: Pull
able 60 Amp Breaker> To: aeroelectric-list@matronics.com> > >> > >First, kn
ow that designers of upper-end production aircraft> > >have made a effort t
o get high-current, noise-carrying> > >conductors off the panel.> >> >Never
heard noise in my plane with B-lead CB in panel.> >I would just say prove
it. Modern internally regulated alternators> >are not noisy so it's a moot
point. Old Gen from days gone by, yes> >noisy.> > George, this has nothing
to do with the style of> regulator. 3-phase rectified AC has a 5% built-in
ripple> component that is a physical artifact of the product.> I've encount
ered magnetically coupled noises in both> automobiles and aircraft. So your
statement about "modern> internally regulated alternators not being noisy"
is> demonstrably in error and your admonition to "prove it"> is a manifest
ation of your proven history of inability> or unwillingness to carry on dis
cussions based on> physics and simple-ideas.> > I've troubleshot and fixed
a number of magnetically> coupled alternator whine problems on aircraft and
once> in my own automobile. It's doubtful that any demonstration> would be
sufficient "proof" to make this phenomenon> real and significant in your l
imited understanding.> Alternators are much more noisy than generators.> >
> > >Third, it has been suggested that a breaker might serve> > >as the las
t-ditch means by which a pilot can bring a runaway> > >alternator to heel .
. . or at least disconnect it from the> > >system. This logic is flawed fo
r several reasons: (1) breakers> > >are designed to disconnect hard downstr
eam faults in a system> > >where the voltage are on the order of 32 volts o
r less. (2)> > >A runaway alternator is capable of raising the b-lead termi
nal> > >to hundreds of volts in milliseconds where it is NOT reasonable> >
>to expect the breaker to also serve as a SWITCH for reliable> > >disconnec
t of the offending alternator. Any attempt to use> > >a breaker (particular
ly a miniature one with plastic housing!)> > >or this purpose is to flirt w
ith probability of cockpit fire> > >and much smoke.> >> >With all due respe
ct I think your logic is flawed. It may fit for external> >regulated altern
ators but not for internally regulated ones.> > It matters not what style o
f alternator is being> considered, any alternator running self-excited by>
a field voltage which is a product of it's own output> is capable of well o
ver 100 volts of output. See:> > http://aeroelectric.com/articles/When_is_1
10V_not_Over_Voltage.pdf> > >> >A CB is RATED to disconnect at 32 volts man
y many times, however> >it can handle much more. No I don't have an absolut
e number but> >when most 12 volt alternators with a so called over voltage
rarely> >exceeds 17 v much less 32 v, your point is moot, 32v good enough.>
> Yes, the runaway alternators that were NOT putting out> hundreds of volt
s were being loaded by a battery that> was dutifully sacrificing itself by
accepting what the> alternator could deliver due to its inherent current> l
imiting.> > But the very act of opening the b-lead on a runaway> alternator
disconnects the battery and all other parts> of the ship's systems. As soo
n as the contacts of the> 'switch' open, the alternator becomes unrestraine
d and> b-lead voltage will rise rapidly to values much greater> than the 32
-volt rating of the breaker. Once you strike> the arc between the opening c
ontacts, one has 100+> volts at 40-60 amps (4,000+ watts) of potential powe
r> being dumped into the fire. This would probably be> contained by an all-
metal enclosure like:> > http://www.aeroelectric.com/Pictures/Contactors/s7
01-1.jpg> > but enclosures like this . . .> > http://www.aeroelectric.com/P
ictures/Contactors/6041_Contactor.jpg> > . . . have proven incapable of con
taining such fires> > http://www.aeroelectric.com/Pictures/Failures/6041_Co
ntactor_Failure.jpg> > > > >> >When you say 100's of VOLTS and Cockpit FIRE
, it's fear mongering> >not based on facts. Science and engineering are bas
ed on facts not> >emotional reasons. CB catch on fire? Really? OK, prove it
.> > It is an absolute certainty that an enclosure like this> > http://www.
aeroelectric.com/Pictures/Breakers/circuitbreakers.jpg> > will not contain
such fires either.> > >> >Small 40 / 60 amp alternators are not pumping 100
's of volts or amps.> >Internally regulated alternators typically go to 16
or 17 volts, if> >regulation fails, easily controlled by a CB. Yes there ma
y have> >been one "screw lose" case where voltage was truly out of control,
> >but it's rare, and the voltage was undetermined. I doubt it got to> >ove
r 32 volts.> > As soon as the runaway alternator is disconnected from> the
system by pulling a breaker, the battery is relieved> of sacrificial duties
and the voltage at the alternator's> b-lead will rise rapidly and to magni
tudes previously cited. . .> the Mother of All Load Dumps.> > >> >Also an A
NL fuse will not blow with 100's of volts, it's a current> >device. If you
want to wire your airplane like a Toyota with fuses, fine,> >but there is n
o need to make stuff up against CB's in the panel.> > Fuses are not expecte
d to protect against over-voltage events> but over-current events. Know tha
t a runaway alternator has> NEVER put out more current that what's establis
hed by the> physics of it's magnetics. I.e, not enough to open the> b-lead
protection irrespective of it's design (assuming> it is sized for sufficien
t headroom to avoid nuisance> tripping). Nonetheless, bus voltages are carr
ied upward> to many times greater than normal bus voltage unless> some well
considered means for stopping it has been included> in the design.> > > >
>Finally, know that a 60A breaker on a 60A alternator is> > >DESIGNED to nu
isance trip. The b-lead protection on an alternator> > >should stay closed
at current levels perhaps 20% higher than> > >the nameplate rating of the a
lternator. The GA spam-can community> > >really blew it when 60A b-lead bre
akers were installed in 100,000+> > >aircraft with 60A alternators.> >> >Ea
sily solved by sizing the CB properly. I guess they don't have> >smart peop
le working for the GA spam-can community. Frankly CB's> >can take slight ov
erloads for a period of time with out a trip. Again> >moot point Bob, if th
e alternator can only put out 45 amps.> > That's what I said. The 60A break
er is too small for> being used with a 60A alternator. Yes, MOST nuisance>
tripping is avoided by the noteworthy time delays> inherent in the design o
f CBs . . . but the majority> of nuisance trips of breakers in light aircra
ft are> the 60A b-lead breaker tied to a 60A alternator.> > Your off-hand c
omment about the intelligence of folks> working in GA is uncalled for and y
et another manifestation> of your long and oft demonstrated history of bell
igerent,> ill-informed, nay ignorant participation on this List.> There are
MANY folks within GA that would very much> like to rectify the condition c
ited . . . but it's never> bubbled to the top-ten-problems list with an air
frame OEM and> the FAA makes it insanely $difficult$ to make even the> simp
lest changes. Hence, this marginal design has> endured for decades more out
of resignation to the> authority of a higher power than of ignorance or ap
athy.> > > > >In my humble opinion, ignoring a lot of experience and> > >th
oughtful reasoning suggesting that panel a mounted, b-lead> > >breaker is n
ot the best-we-know-how-to-do.> > >Bob . . .> >> >What?> >> >Fuses are fine
. Buth with (stock) internal regulation the CB is a good> >reason to use a
B-lead CB. Other engineers have worked on this> >Bob. The pull-able CB for
the B-lead is specified. It's irresponsible of> >you to be so stubborn and
opinionated, making ONE blanked edict> >that one size fits all. Fuses are n
ot a BE ALL solution for every> >application. Follow the manufactures recom
mendation!> > This isn't a fuses/breakers discussion, it's> an examination
of the physics which govern assembly> of some exceedingly simple ideas into
recipes for> success with an acknowledgment of hazards which> should be co
nsidered as part of a thoughtful design.> > >> >In my humble opinion, I dis
agree with Bob with my thoughtful reasoning> >and facts. I don't care what
you use but know why you are using it. I> >don't believe you will have nois
e or won't be able to disconnect the> >b-lead manually if you want to. When
people talk 100's of volts & fire> >they are exaggerating in non-scientifi
c emotional arguments, not> >engineering. Have Bob prove these are real pro
blems. I could come> >up with lots of NIT PICK reasons a fuse really is a p
oor choice.> > George, you have been politely requested to keep> your comme
nts on this topic to yourself . . . they've> been read many times for years
on this List and debunked> as recorded and published at:> > http://www.aer
oelectric.com/articles/gmcjetpilot.html> > http://aeroelectric.com/articles
/The_Truth_about_Crowbar_OV_Protection.pdf> > You have designed nothing, fi
xed nothing, contributed> nothing to the understanding of physics, serviced
no> customers, taught no classes, or offered a 100% satisfaction> assured
warranty for your products. Yet you persist> in lurking at the edges of a s
andbox not of your> construction to throw rocks and mud while hiding behind
> a pseudonym decorated with much alphabet soup of> self proclaimed titles/
accolades. You claim superior> engineering insight while never having demon
strated> it with useful work-product.> > I've demonstrated/experienced/expl
ained every assertion> I've ever made based on my hands-on experiences with
these> systems since I did my first OV relay design for Cessna> Aircraft i
n 1975. Your belittling diatribes and circular> arguments contribute nothin
g to the advancement of> our science, understanding or art and yet you deig
n to> call me a liar. Your brand of 'science' is not welcome> in this class
room. You sir are the secretive, fraudulent> participant in these discussio
ns and I will ask you> politely for the third or forth time, please go away
.> > Bob . . .> > (---------------------------------------)> ( . . . a long
habit of not thinking )> ( a thing wrong, gives it a superficial )> ( appe
arance of being right . . . )> ( )> ( -Thomas Paine 1776- )> (-------------
==================> > >
Message 18
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| Subject: | Re: Tefzel cables and d-sub connectors |
At 06:55 AM 11/21/2007 -0800, you wrote:
>
>I am have reached the point in my building where I have to address some
>electrical design issues. I need to install the servo for the R.A. Allen
>electric elevator trim tab. The servo has 5 leads, and is supplied with a
>length of 5-conductor Belden 8445 cable to connect to the controls in the
>cockpit. A check on the Internet shows that this cable is PVC insulated
>with 5 22AWG wires. I have a several questions.
>
>1. I was planning to use Tefzel insulated cable as much as possible. Is it
>worthwhile to replace R.A. Allen's PVC insulated cable with Tefzel
>insulated cable?
See:
http://aeroelectric.com/articles/macservo/macservo.html
>2. For this application cable would be better than 5 individual wires,
>because the wires must pass outside the skin from the elevator to the
>fuselage. After looking around on the Internet, I was unable to find a
>5-conductor cable with Tefzel wire insulation and a Tefzel jacket. I did
>find a company, TPC Wire,
>
>http://www.tpcwire.com/tpc/pdf/03_TrOxCable_6.pdf,
>
>that sells 100 ft lengths of shielded cable with Tefzel wire insulation
>and a polyurethane exterior cover that should work (part no. 61506). They
>don't have 5 conductor cable, but the 6 conductor cable would not be much
>heavier. Does such a cable look like a reasonable substitute? Are there
>other sources for Tefzel insulated cable that I should consider?
Run individual 22AWG wires from the connector forward.
The connector as described is light enough to simply
be covered with heat shrink and supported by the cable
assembly, no need to mount it separately. There's no
good reason to treat your trim actuator wires any
differently than a bundle of wires that carry nav,
strobe and antenna wires to the back of the airplane.
>3. The servo instructions suggest soldering the cable conductors to the
>servo leads and wrapping the joints with electrical tape.
It was my first view of a behind the panel rat's nest
of odd pieces of wire and way too much electrical tape
that prompted me to write the first edition of the
'Connection 21 years ago.
> I was originally planning to use butt splice crimp connectors instead of
> soldering. I'm now considering using a 9 conductor d-sub plug. Are the
> d-sub plugs a good choice for a remote location, like the elevator?
Yup, that works. There are some smaller, classier
connectors you could consider too . . . but they're
more expensive, take special tools and don't do
any better job than a d-sub.
>4. If one uses a d-sub, should the plug itself be secured to the elevator
>(how?) or would cable ties or an adel clamps on the cable provide adequate
>support.
Float it on the cable.
>5. Also, since TPC Wire has a $100 minumum order, it behooves me to buy
>cable for other uses in the airplane in this one order. E.g., power for
>the nav lights, headlights, etc. One use that I'm considering is to buy
>some 24 conductor cable to pass through the firewall to carry engine
>instrument signals.
Please don't do this. In over 30 years of
systems design and integration I've never seen
a practical need for multi-conductor bundles
other than those called out as shielded
for the purpose of protecting a signal path.
Build your bundles one wire at a time.
> Which brings me back to the d-sub connectors. Would d-subs be reasonable
> replacement for the terminal strips that I have seen used to connect
> engine instruments to wires passing through the firewall?
Sure.
> Can d-subs handle engine compartment temperatures?
Yes.
> Will thermocouple leads crimped into d-sub pins work OK?
Yes. Been doing it for years.
> Are d-subs robust enough to endure the correction of wiring goofs?
Depends on how clumsy you are. I've got connectors
in my data acquisition systems where some pins have
been removed/replaced over a dozen times. Be nice to
them and they'll do well for you for a long time.
Terminal strips are labor intensive, drive up
parts count, use threaded (ugh) fasteners. Crimped
joints into machined pins/terminals are far less
troublesome for maintenance and cost of ownership.
Bob . . .
Message 19
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| Subject: | Location of battery bus |
Bevan, I am using Z13/8 with the HD Endurance bus plus an Aux Bat and bus
for the EFIS. I tried to shoot a picture at about the same angle as your
picture with the tray down. I personally think it's very easy to get to,
but probably not in flight. My copilot stick is removable, pic attached.
Also Aux Bat and bus under AHRS. Note battery (P212 7ah) is attached below
AHRS.
Hope this helps, locations work nice for me.
Bill S
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of B Tomm
Sent: Wednesday, November 21, 2007 12:14 AM
Subject: RE: AeroElectric-List: Location of battery bus
Thanks Bill
Looks very good. Nice fuse block mount. Can you access it without taking a
control stick out and crawling underneath? Maybe just leaning over sideways
from the pilot seat?
I see a SD8 ? alternator. Can I assume you've wired up per Z13/8? Just a
guess, correct me if I'm wrong. Based on Bob's comments, I'm thinking that
Z13/8 will be ideal for me. Not sure what size Odyssey batt I need. Have
not completed a load analysis yet. If you are flying yet, I would like to
know what schematic Z drawing you're using and how you like it.
Bevan
Attached is a pic of my panel so far. No real wiring done yet. Just making
everything fit.
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bill
Schlatterer
Sent: Tuesday, November 20, 2007 9:21 PM
Subject: RE: AeroElectric-List: Location of battery bus
Bevan, this is what I did on my 7a for block locations. Small Tab forest on
FW side to large forest on cabin side. Fuse blocks on the inside are on a
swing down tray. Ran the battery lead to the always hot bus to a fuse slot
which really protects the wrong end of the wire but it seemed better than
nothing (maybe a fusible link on the battery end would be better). Wire is
about 14" from Battery to bus as I remember it but not likely to have a
problem.
Bill S
7a
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of B Tomm
Sent: Tuesday, November 20, 2007 3:28 AM
Subject: AeroElectric-List: Location of battery bus
Good morning Bob,
Considering Z-13/20 architecture in an RV7A. The Vans recommended position
for the battery is on the firewall in the engine compartment which I agree
with. That being said, the contactors would be located nearby. Would it
follow that the battery bus should also be located on the engine side of the
firewall and if so, would it be appropriate to use a fuse block style as
we've come to appreciate? In other words, would the fuse block style and
associated faston terminals stand up in the FF environment? I would prefer
to see the fuses inside the cockpit just aft of the firewall (cleaner
environment), but to get to here there would be a little more than 6 inches
of unprotected wire.
Thanks again.
Bevan
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Message 20
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| Subject: | RE: Pullable 60 Amp Breaker |
At 07:43 PM 11/21/2007 -0600, you wrote:
>
>
>With several hundred, uh thousands (they become blurred and seemingly
>insignificant) of flight hours I now attempt a life-long goal of building
>my own airplane. My self-professed weakness is wiring, electronics and
>electricity in general. Thus, my reason for joining this forum. I read
>every post with an open mind and hopefully add to my limited understanding
>of the traveling electron.
>
>In following this thread of "Pullable 60 Amp Breaker" I am reminded of
>something I learned a long time ago. The only difference between a jet
>pilot and a jet engine is the fact that a jet engine stops whining when
>you shut it down.
It is for folks such as yourself that at least
some among us must go out of their way to protect
the liberties of all against the attacks of a
few. This is the simple-idea that defines
honorable behavior. I (and I'm sure others)
will continue to sift and refine the inventions
to be formed from solid understanding of their
component simple-ideas. You have come to the
right place sir.
Bob . . .
Message 21
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| Subject: | Re: Running avionics on power supply |
At 07:56 AM 11/21/2007 -0500, you wrote:
><recapen@earthlink.net>
>
>No replies to my initial post, so trying again....
>
>Should there be any issues in running my electrical system with a power
>supply instead of the alternater/engine running? I have a battery in the
>circuit (PC680).
>Do I need to connect the power supply directly to the battery or can I
>hook it to my shunt to simulate the power coming from the alternator?
>
>Just want to make sure that I don't fry anything.....
Some years ago I sold a 13.8 volt, 25A switchmode
power supply along with instructions on how to wire
it to the aircraft such that it emulated the ship's
alternator. This allowed a builder to fire up all but
the heaviest loads on the electrical system and to
exercise all the systems just as if the engine were
running and the alternator was turned ON.
If you have a well behaved power supply (13.8 volts
preferred, current limited against accidental shorts)
then you can basically hook it up about anywhere. Across
the battery is fine. This makes the battery master
capable of disconnecting your supply from system by
turning the battery master OFF.
See:
http://www.mpja.com/prodinfo.asp?number=5386+PS
also, the various smart-chargers with more robust
outputs like those shown on pages 6 and 7 of:
http://www.schumacherproducts.com/assets/pdf/sec_catalog.pdf
can be used. Again, just connect across the battery,
plug into wall and use the battery master for
control.
Wall-Mart sells several of these models. Get one
with 10A or more capability.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
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