Today's Message Index:
----------------------
1. 05:44 AM - volt/load meter (Jones, Michael)
2. 06:19 AM - Re: RFI (Robert L. Nuckolls, III)
3. 06:20 AM - Re: multi-wire cable (Robert L. Nuckolls, III)
4. 06:21 AM - Re: volt/load meter (Robert L. Nuckolls, III)
5. 06:35 AM - Bendix King KY 97A question (PGLong@aol.com)
6. 06:37 AM - (Gary Casey)
7. 06:56 AM - Re: Double OVM-14's (Julia)
8. 07:02 AM - Crimping vs. soldering wires? (Julia)
9. 07:05 AM - Re: RFI (Benford2@aol.com)
10. 07:05 AM - Re: Bendix King KY 97A question (Robert L. Nuckolls, III)
11. 07:06 AM - Re: Data logger (Mark Phillips)
12. 07:45 AM - Re: Crimping vs. soldering wires? (Charlie Dunn)
13. 08:21 AM - Re: Crimping vs. soldering wires? (Matt Prather)
14. 08:22 AM - Re: Re: runaway, self regulated alternators (Paul Messinger)
15. 08:26 AM - Re: Double OVM-14's (Robert L. Nuckolls, III)
16. 08:29 AM - Re: Crimping vs. soldering wires? (Robert L. Nuckolls, III)
17. 08:39 AM - Re: (Robert L. Nuckolls, III)
18. 08:39 AM - Re: Data logger (Robert L. Nuckolls, III)
19. 08:40 AM - Re: RFI (Robert L. Nuckolls, III)
20. 09:04 AM - Re: Double OVM-14's (Julia)
21. 09:19 AM - Re: Crimping vs. soldering wires? (Cy Galley)
22. 10:58 AM - Re: Double OVM-14's (Robert L. Nuckolls, III)
23. 11:04 AM - Re: Crimping vs. soldering wires? (Robert L. Nuckolls, III)
24. 11:19 AM - Firewall Flange sealant? (Julia)
25. 12:27 PM - Re: (Paul Messinger)
26. 12:38 PM - Re: runaway, self regulated alternators (Robert L. Nuckolls, III)
27. 12:56 PM - Re: (Matt Prather)
28. 01:23 PM - Re: RG battery mounting positions (David Swartzendruber)
29. 03:00 PM - Re: RG battery operating positions (Robert L. Nuckolls, III)
30. 03:00 PM - Re: Re: RG battery mounting positions (Robert L. Nuckolls, III)
31. 05:01 PM - Re: Firewall Flange sealant? (Robert L. Nuckolls, III)
32. 05:08 PM - off line for a few days . . . (Robert L. Nuckolls, III)
33. 05:21 PM - Re: 12 vs 28 volts (Robert L. Nuckolls, III)
Message 1
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--> AeroElectric-List message posted by: "Jones, Michael" <MJones@hatch.ca>
Bob
If I get the volt/load meter from westach to use in my kit plane as a stand
alone meter should I install a switch with it.
I seem to recall reading that when you sold it as a package with other
components it would switch automatically between main and back up
alternator.
I am planning on the 8 amp B&C alternator as backup to main 60 amp.
Mike
Message 2
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:54 PM 3/12/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "MARK H DELANO"
><delano60@email.msn.com>
>
>I have tried all your suggestions to eliminate the RFI produced by this Turn
>& Bank indicator. The iron wrap helped quite a bit but did not eliminate
>the noise buy itself, however when I would move my hand within 5 or 6 in. of
>the gyro, but not touching it, the RFI would almost completely disappear.
>Since I will operate in Class B airspace the com radio is an absolute
>requirement, so this Chinese knock off is going back to Spruce and a high
>quality unit will replace it.
Interesting! Thank you for sharing that with us. I wish
I were doing something useful in the RFI lab at RAC, I'd
really like to borrow your problem-child and get a
laboratory-grade look at it.
Be sure and rattle Spruce's cage pretty good over this.
They ought to give you a discount on the replacement.
Bob . . .
Message 3
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| Subject: | multi-wire cable |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:47 PM 3/12/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: Ed Holyoke <bicyclop@pacbell.net>
>
>Hi Bob,
>
>How thick is the shielded trio?
.120"
Message 4
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| Subject: | Re: volt/load meter |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:42 AM 3/13/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Jones, Michael" <MJones@hatch.ca>
>
>Bob
>
>If I get the volt/load meter from westach to use in my kit plane as a stand
>alone meter should I install a switch with it.
>
>I seem to recall reading that when you sold it as a package with other
>components it would switch automatically between main and back up
>alternator.
>
>I am planning on the 8 amp B&C alternator as backup to main 60 amp.
Perhaps two switches. One to switch the ammeter from aux to main
alternators, one to switch voltmeter from main to e-bus.
Bob . . .
Message 5
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| Subject: | Bendix King KY 97A question |
--> AeroElectric-List message posted by: PGLong@aol.com
I purchased a RV-4 with a blank spot in the comm tray. The previous owner,
whom I cannot contact had a Bendix King KY-97A installed. I'm trying to
locate one to plug into the existing tray and wiring. Is there a way for me
to tell which model he had? The current tray is wired to a Sigtronics
Intercom SPA-400-TSO with no speaker and headphone jacks for two persons.
Kinda hate to buy a KY-97A without knowing the model number he had. Below is
the information I got from a Bendix King website. Hopefully, the wiring is
the same for all. If not, is there a specific could I look for that would
identify the unit from the existing connection wiring? I do have the KY 97
wiring diagram that Bob has on his website.
KY-97A VHF Communications Transceiver Description
Model:
064-1051-10 25Khz receiver selectivity, 500ohm headphone audio output, 720
channels
064-1051-30 25Khz receiver selectivity, 500ohm headphone audio output, 760
channels
064-1051-50 25Khz receiver selectivity, 4W into 4ohm audio output, 720
channels
064-1051-51 50Khz receiver selectivity, 4W into 4ohm audio output, 720
channels
064-1051-60 25Khz receiver selectivity, 4W into 4ohm audio output, 760
channels
064-1051-61 50Khz receiver selectivity, 4W into 4ohm audio output, 760
channels
064-1051-70 Crown series version of -60 unit with solid black face and no
silver lining trim
Thanks for your input
Pat Long
Working on an RV-4
Message 6
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--> AeroElectric-List message posted by: "Gary Casey" <glcasey@adelphia.net>
<<Let not your heart be troubled . . . for all the fire-breathing
capabilities of an RG battery, you have never had a greater
opportunity to design your airplane for efficiency of space and
function with virtually no risk from the concerns cited. Mount
it where it fits best.
Bob . . .>>
That brings up another question: For an RG battery, how far from an upright
orientation can you go? Many of the potential surfaces for mounting aren't
vertical.
Gary Casey
Message 7
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| Subject: | Re: Double OVM-14's |
--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
But would it work? if one failed, would the other one do the trick?
"Robert L. Nuckolls, III" <bob.nuckolls@cox.net> wrote:--> AeroElectric-List message
posted by: "Robert L. Nuckolls, III"
At 10:17 AM 3/12/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: Julia
>
>
>bob:
>
>since the OVM-14's are relatively tiny and light units, could one put two
>of these in and that way if one failed, the other would be there to
>work? My worry with things like this is always what do I do if 6 years
>from now, this OVM-14 fails and B&C Electirical doesn't sell it
>anymore? Would a typical A&P mechanic have a clue as to how to replace
>this particular module - if we were so fortunate as to be able to figure
>out that it even failed?
They should be tested every annual like every other OV protection
product on any airplane. It's easy to do. Instructions for doing
so should have come with it. As an all solid-state
device, probability of decades of trouble-free service is quite
good. There will always be a direct replacement for this device
from either B&C, AeroElectric Connection, and perhaps others . . .
Documentation on how to build your own is downloadable from
my website. If push came to shove, you can build one. The parts
are not critical. This circuit has been built by a number
of builders with success.
If the device does fail to function, it can be repaired. The
heat shrink can be cut off for troubleshooting.
>What do you think - would this work? See Z-11 - the OVM-14 just goes from
>the pin 4 wire to ground - so just add another in beside it going from pin
>#4 to ground.
I think this would be a waste of money.
Bob . . .
---------------------------------
Message 8
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| Subject: | Crimping vs. soldering wires? |
--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
I heard someone say don't solder wires as the vibrations will crack at some point?
I installed a battery cable last night and after crimping it I soldered it. Now
if the solder cracks, it's still been crimped - so wouldn't that be the best
of both worlds?
I had intended to solder all of my connections everywhere - what is the general
recommended procedure?
---------------------------------
Message 9
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--> AeroElectric-List message posted by: Benford2@aol.com
In a message dated 3/13/2003 7:20:07 AM Mountain Standard Time,
bob.nuckolls@cox.net writes:
>
> Interesting! Thank you for sharing that with us. I wish
> I were doing something useful in the RFI lab at RAC, I'd
> really like to borrow your problem-child and get a
> laboratory-grade look at it.
>
I have the same T&B and I have not powered up the panel yet. If it does the
same thing I will donate it to ya so you can do an autopsy on it and expose
the weakness of this unit to all of us loyal readers. Ben Haas N801BH.
Message 10
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| Subject: | Re: Bendix King KY 97A question |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:32 AM 3/13/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: PGLong@aol.com
>
>I purchased a RV-4 with a blank spot in the comm tray. The previous owner,
>whom I cannot contact had a Bendix King KY-97A installed. I'm trying to
>locate one to plug into the existing tray and wiring. Is there a way for me
>to tell which model he had? The current tray is wired to a Sigtronics
>Intercom SPA-400-TSO with no speaker and headphone jacks for two persons.
>Kinda hate to buy a KY-97A without knowing the model number he had. Below is
>the information I got from a Bendix King website. Hopefully, the wiring is
>the same for all. If not, is there a specific could I look for that would
>identify the unit from the existing connection wiring? I do have the KY 97
>wiring diagram that Bob has on his website.
there are generally no variations in wiring between production
changes of a specific model. The pin-out reference I have doesn't
list any variations on the KY-97 other than the KY-97A.
Any one of the products you listed will play in your airplane.
Bob . . .
Message 11
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--> AeroElectric-List message posted by: Mark Phillips <ripsteel@edge.net>
> I've got plans for
> a super sensitive, temperature compensated pressure
> transducer that gives me +/- 20 foot accuracy to
> 60,000 feet and better than 1% accuracy for pitot
> pressures to 300 kts.
Does this mean we will be seeing a reasonably accurate, affordable altitude control
device in
the near future? How much panel space do I need to reserve and when can we expect
delivery
or requests for beta testers?
From The PossumWorks in TN
Mark do not archive
Message 12
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| Subject: | Crimping vs. soldering wires? |
--> AeroElectric-List message posted by: "Charlie Dunn" <cdunn@fhtc.kansas.net>
We have had a series of planes having problems with wires breaking because
the solder flowing back into the wire
3/8 to 1/2" and making a solid to flexible junction a little ways back from
the terminal. The wire will break at this
junction after a while. If it is the wrong wire things get very Quite.
Charles Dunn
Flint Hills Technical School
--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
I heard someone say don't solder wires as the vibrations will crack at some
point?
I installed a battery cable last night and after crimping it I soldered it.
Now if the solder cracks, it's still been crimped - so wouldn't that be the
best of both worlds?
Message 13
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| Subject: | Crimping vs. soldering wires? |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Have these breakages occurred only in places where the wire runs
some distance from the solder joint unsupported by other forms of
strain relief? I don't know what the standard is, and it probably varies
by wire gauge, but it seems like a properly installed wire should have
strain relief (support, adel clamp, or similar) within 4-6" from the
terminal,
and then every 12" beyond that. This should reduce the effects of
vibration which might be causing the wire to "whip" and fatigue.
Regards,
Matt-
> --> AeroElectric-List message posted by: "Charlie Dunn"
> <cdunn@fhtc.kansas.net>
>
> We have had a series of planes having problems with wires breaking
> because the solder flowing back into the wire
> 3/8 to 1/2" and making a solid to flexible junction a little ways back
> from the terminal. The wire will break at this
> junction after a while. If it is the wrong wire things get very Quite.
> Charles Dunn
> Flint Hills Technical School
> --> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
>
>
> I heard someone say don't solder wires as the vibrations will crack at
> some point?
>
> I installed a battery cable last night and after crimping it I soldered
> it. Now if the solder cracks, it's still been crimped - so wouldn't that
> be the best of both worlds?
>
>
Message 14
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| Subject: | Re: runaway, self regulated alternators |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@tenforward.com>
Comments in context and some snipping.
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: AeroElectric-List: Re: runaway, self regulated alternators
Thus I have concluded that the above protection
> >circuit is only a partial fix and that ANY alternator protection circuit
for
> >aircraft must also disconnect the field current.
>
> The risk is to the field windings which get mucho volts applied
> to them during the runaway event . . . which doesn't last long.
> Perhaps 10 seconds before the field wires burn in two. Where
> is the concentration of energy liberation adjacent to combustibles
that
> poses a risk of fire?
Many years ago I saw such a failure and the alternator housing was partially
melted. My point is that each alternator is different and its hard to say
what fails and how long it takes. Why even consider the risk??
>
> >The rising output voltage will rise until the internal diodes start
shorting
> >out from overvoltage and this provides additional load (HEAT).
>
> But consider that an alternator is incapable of delivering
> any more current than it's magnetics will support . . . even
> in a runaway condition, a 60A alternator is still a 60A alternator.
> (our technique for running 14 volt alternators in a 28v system
> using a special regulator might be called a "controlled runaway"
> except that we go to pains to make sure the field is not over
> driven . . . but it's still a 40/60A alternator).
Years ago there were "Kits" to convert the alternator to 120V operation.
Other than controlling field current the 120V alternator has the same output
current rating as the 12V version IE 60 amps. Some actually could be driven
to over 200V as it depended on the voltage rating of the diodes.
>
> So any degree of heating (I-squared*R) is relatively constant
> irrespective of how much voltage the machine is generating during
> an open circuit runaway. Shorting diodes is the best thing
> you could hope for. A shorted diode is a cooler diode. Further,
> as soon as you take out an upper/lower pair of diodes in the
> full-wave array, output voltage goes to zero, field excitation
> goes away and the critter stalls and shuts itself down. The
> worst case is that the diodes hang in there (most are capable of a
LOT
> more that we might suspect) and 100+ volts makes raises
> field current to 25 amps or so . . . that 22AWG copper field
> winding won't stay in place very long. Exposed leadwires
> would fuse before the field winding proper even has a chance
> to warm up. It's all over in seconds.
I do not agree that shorting diodes will always reduce the heat. What
shorted diodes do is short windings out that still generate current and that
current generates heat.
Perhaps but then again your 10 seconds is a lot of heat and included the
possibility of the external feed to the regulator getting on line and
supplying HV back to the source. Your designs do not have any overvoltage
protection I can find other than for the alternator output. Relying on the
Mfgrs to meet the latest transient design rules is a foolish position on
this list as many will not use the latest main line mfgrs products etc. Use
of transient absorbers is so simple and low cost its perhaps belt and
suspenders in some cases and the only line of defense in others.
> We've see the test. There was at least one builder
> who sent his alternator back for overhaul wherein he
> failed to provide ANY kind of ov protection and assumed
> that the alternator had a built in regulator. So through
> a combination of mis-wiring and poor choice of switch
> arrangements, he managed to get an alternator on line
> without a battery or regulator. The alternator didn't
> even smell really bad. The leadwire between slip ring
> and field winding had opened like a fusible link. We
> could probably have spliced it and the alternator would
> have worked fine.
Incomplete analysis if you did not look for the cause. Your comment on the
lead wire failure is the result, not the cause and perhaps only a secondary
result.
Also that is only an example of one from one mfgr.
Regardless we are both entitled to our opinions and I am unwilling to take
even a remote chance when the solution is clearly available and easy to do.
I feel that not disconnecting the field for at least your stated 10 seconds
is 10 seconds more then is necessary and simply another unnecessary risk.
Without a Failure Modes and Effects Analysis (FMEA) its risky to base
conclusions on theory and one example.
Paul
Message 15
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| Subject: | Re: Double OVM-14's |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:52 AM 3/13/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
>
>
>But would it work? if one failed, would the other one do the trick?
Depends on how it failed. All of the failures I've repaired
were failed shorted. In this case, the field breaker cannot
be reset and the system is down. In each case, the ovm
failed because it was mis-wired into the system and didn't
have a circuit breaker in series with it to open up when
the crowbar fired.
IF they fail to operate, then having a second OVM in parallel
with it will still get a runaway alternator under control.
Bob . . .
Message 16
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| Subject: | Crimping vs. soldering wires? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:44 AM 3/13/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "Charlie Dunn"
><cdunn@fhtc.kansas.net>
>
>We have had a series of planes having problems with wires breaking because
>the solder flowing back into the wire
>3/8 to 1/2" and making a solid to flexible junction a little ways back from
>the terminal. The wire will break at this
>junction after a while. If it is the wrong wire things get very Quite.
>Charles Dunn
>Flint Hills Technical School
>--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
>
>
>I heard someone say don't solder wires as the vibrations will crack at some
>point?
>
>I installed a battery cable last night and after crimping it I soldered it.
>Now if the solder cracks, it's still been crimped - so wouldn't that be the
>best of both worlds?
See http://www.aeroelectric.com/articles/terminal.pdf
and http://www.aeroelectric.com/articles/rules/review.html
Bob . . .
Message 17
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:31 AM 3/13/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Gary Casey" <glcasey@adelphia.net>
>
><<Let not your heart be troubled . . . for all the fire-breathing
> capabilities of an RG battery, you have never had a greater
> opportunity to design your airplane for efficiency of space and
> function with virtually no risk from the concerns cited. Mount
> it where it fits best.
>
> Bob . . .>>
>
>That brings up another question: For an RG battery, how far from an upright
>orientation can you go? Many of the potential surfaces for mounting aren't
>vertical.
Mount it in any position. Upside down if you like.
Bob . . .
Message 18
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:03 AM 3/13/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: Mark Phillips <ripsteel@edge.net>
>
> > I've got plans for
> > a super sensitive, temperature compensated pressure
> > transducer that gives me +/- 20 foot accuracy to
> > 60,000 feet and better than 1% accuracy for pitot
> > pressures to 300 kts.
>
>Does this mean we will be seeing a reasonably accurate, affordable
>altitude control device in
>the near future? How much panel space do I need to reserve and when can
>we expect delivery
>or requests for beta testers?
That's a possibility but it's way down on the list . . .
Bob . . .
Message 19
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:01 AM 3/13/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: Benford2@aol.com
>
>In a message dated 3/13/2003 7:20:07 AM Mountain Standard Time,
>bob.nuckolls@cox.net writes:
>
>
> >
> > Interesting! Thank you for sharing that with us. I wish
> > I were doing something useful in the RFI lab at RAC, I'd
> > really like to borrow your problem-child and get a
> > laboratory-grade look at it.
> >
>
>I have the same T&B and I have not powered up the panel yet. If it does the
>same thing I will donate it to ya so you can do an autopsy on it and expose
>the weakness of this unit to all of us loyal readers. Ben Haas N801BH.
Thank you!
Bob . . .
Message 20
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| Subject: | Re: Double OVM-14's |
--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
So does the breaker you show in z-11 - the 5 amp alternator field breaker - take
care of this issue -
thanks
"Robert L. Nuckolls, III" <bob.nuckolls@cox.net> wrote:--> AeroElectric-List message
posted by: "Robert L. Nuckolls, III"
At 06:52 AM 3/13/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: Julia
>
>
>But would it work? if one failed, would the other one do the trick?
Depends on how it failed. All of the failures I've repaired
were failed shorted. In this case, the field breaker cannot
be reset and the system is down. In each case, the ovm
failed because it was mis-wired into the system and didn't
have a circuit breaker in series with it to open up when
the crowbar fired.
IF they fail to operate, then having a second OVM in parallel
with it will still get a runaway alternator under control.
Bob . . .
---------------------------------
Message 21
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| Subject: | Re: Crimping vs. soldering wires? |
--> AeroElectric-List message posted by: "Cy Galley" <cgalley@qcbc.org>
On something that big, Shouldn't see a problem.
The problem with the soldering is when the wire flexes, it will break at the
edge of the soldering to the wire. Solution is always to provide good
support to the wire to prevent flexing or not to solder.
Crimping and Soldering is an effort in futility.
Just crimping alone is better because it doesn't have the sharp transition
between the wire and the heavy soldering.
Cy Galley, TC - Chair, Emergency Aircraft Repair, Oshkosh
Editor, EAA Safety Programs
cgalley@qcbc.org or experimenter@eaa.org
Always looking for articles for the Experimenter
----- Original Message -----
From: "Julia" <wings97302@yahoo.com>
Subject: AeroElectric-List: Crimping vs. soldering wires?
> --> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
>
>
> I heard someone say don't solder wires as the vibrations will crack at
some point?
>
> I installed a battery cable last night and after crimping it I soldered
it. Now if the solder cracks, it's still been crimped - so wouldn't that be
the best of both worlds?
>
> I had intended to solder all of my connections everywhere - what is the
general recommended procedure?
>
>
> ---------------------------------
>
>
Message 22
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| Subject: | Re: Double OVM-14's |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:02 AM 3/13/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
>
>
>So does the breaker you show in z-11 - the 5 amp alter
>nator field breaker - take care of this issue -
>thanks
yes
Message 23
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| Subject: | Re: Crimping vs. soldering wires? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:18 AM 3/13/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "Cy Galley" <cgalley@qcbc.org>
>
>On something that big, Shouldn't see a problem.
>
>The problem with the soldering is when the wire flexes, it will break at the
>edge of the soldering to the wire. Solution is always to provide good
>support to the wire to prevent flexing or not to solder.
>
>Crimping and Soldering is an effort in futility.
>
>Just crimping alone is better because it doesn't have the sharp transition
>between the wire and the heavy soldering.
How so? If your crimp tool puts enough mash on the
joint to become gas-tight, then the terminal and
every strand of the wire have become a single entity
with zero volume of airspace between parts . . . which
is exactly what happens when you solder.
Wires need support outside the gas-tight area whether
you crimp or solder. That's how the PIDG terminals
(and lesser cousins) came to be. A terminal soldered
to the end of a wire needs some heat shrink support
too (Figure 9-3 in the 'Connection).
Bob . . .
Message 24
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| Subject: | Firewall Flange sealant? |
--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
What's the best thing to use for sealant on the flanges which make up my firewall
wire penetration - i'm using SS tubing welded to a flange - so what would
go between the flange and the firewall - to make it airtight? I"m not talking
about around the wires - but just between the flange and firewall? how about
proseal - would that be ok -or should it be some kind of fireproof silicone
- I think someone mentinoed that once, I cannot seem to find anything in aircraft
spruce - can anyone point me in the right direction for of where I might
get the correct product here?
thanks
---------------------------------
Message 25
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--> AeroElectric-List message posted by: "Paul Messinger" <paulm@tenforward.com>
Many mfgrs include insytructions to not mount that way as the vents can then
discharge caustic materials.
Concord told me to not even mount on its side.
What ever
Paul
> Mount it in any position. Upside down if you like.
>
> Bob . . .
>
>
Message 26
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| Subject: | Re: runaway, self regulated alternators |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:11 AM 3/13/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Paul Messinger"
><paulm@tenforward.com>
>
>Comments in context and some snipping.
>
>----- Original Message -----
>From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>To: <aeroelectric-list@matronics.com>
>Subject: AeroElectric-List: Re: runaway, self regulated alternators
>
>
> Thus I have concluded that the above protection
> > >circuit is only a partial fix and that ANY alternator protection circuit
>for
> > >aircraft must also disconnect the field current.
> >
> > The risk is to the field windings which get mucho volts applied
> > to them during the runaway event . . . which doesn't last long.
> > Perhaps 10 seconds before the field wires burn in two. Where
> > is the concentration of energy liberation adjacent to combustibles
>that
> > poses a risk of fire?
>
>Many years ago I saw such a failure and the alternator housing was partially
>melted. My point is that each alternator is different and its hard to say
>what fails and how long it takes. Why even consider the risk??
There are lots of things that can come unhooked, broken
or leak that increase the risk of fire in every
engine flying. We work to drive those risks down by
understanding weak points of every component
and deciding if the level of robustness justifies its
use in our airplane. What were the circumstances that
produced the outcome you observed? I too have seen
toasted alternators. Too many of them came off of crashes
where people were hurt or killed. NONE of them
were the result of an uncontrolled, ov condition.
> >
> > >The rising output voltage will rise until the internal diodes start
>shorting
> > >out from overvoltage and this provides additional load (HEAT).
> >
> > But consider that an alternator is incapable of delivering
> > any more current than it's magnetics will support . . . even
> > in a runaway condition, a 60A alternator is still a 60A alternator.
> > (our technique for running 14 volt alternators in a 28v system
> > using a special regulator might be called a "controlled runaway"
> > except that we go to pains to make sure the field is not over
> > driven . . . but it's still a 40/60A alternator).
>
>Years ago there were "Kits" to convert the alternator to 120V operation.
>Other than controlling field current the 120V alternator has the same output
>current rating as the 12V version IE 60 amps. Some actually could be driven
>to over 200V as it depended on the voltage rating of the diodes.
Yup. When I went to work for Electro-Mech for the first time
in about 1974, they were in the middle of a recall on just such
a kit. Based on an article in Popular Science or some similar
magazine, you disconnect the b-lead and tie it to a wall
receptacle in a box under the hood of your car. Install a throttle
so that you can adjust engine rpm to some relatively fixed level.
Start the engine. Regulator sees low bus volts and turns on
hard. Pull out throttle until the voltmeter in the kit reads
90 volts DC. Most series wound motors ran better on DC than
AC and 90 volts or so gave nearly equal performance.
The recall was initiated because several disgruntled customers
were fixing to sue us for replacement alternators after installing
our kit . . . seems the diodes in their alternators wouldn't
take the voltage and failed. In this case, the field sees
a fixed voltage from the battery of about 12v. So in spite of
the alternator's tortured diodes failing, abuse to the inner
workings would continue as long as the engine was running.
> >
> > So any degree of heating (I-squared*R) is relatively constant
> > irrespective of how much voltage the machine is generating during
> > an open circuit runaway. Shorting diodes is the best thing
> > you could hope for. A shorted diode is a cooler diode. Further,
> > as soon as you take out an upper/lower pair of diodes in the
> > full-wave array, output voltage goes to zero, field excitation
> > goes away and the critter stalls and shuts itself down. The
> > worst case is that the diodes hang in there (most are capable of a
>LOT
> > more that we might suspect) and 100+ volts makes raises
> > field current to 25 amps or so . . . that 22AWG copper field
> > winding won't stay in place very long. Exposed leadwires
> > would fuse before the field winding proper even has a chance
> > to warm up. It's all over in seconds.
>
>I do not agree that shorting diodes will always reduce the heat. What
>shorted diodes do is short windings out that still generate current and that
>current generates heat.
But the current is generated because the field winding has
mucho volts fed to it by virtue of the runaway condition. If
you get an upper/lower pair shorted (equal to shorting the b-lead
terminal to ground) then output of the alternator (and field voltage)
goes to zero . . . the system dies.
>Perhaps but then again your 10 seconds is a lot of heat and included the
>possibility of the external feed to the regulator getting on line and
>supplying HV back to the source. Your designs do not have any overvoltage
>protection I can find other than for the alternator output. Relying on the
>Mfgrs to meet the latest transient design rules is a foolish position on
>this list as many will not use the latest main line mfgrs products etc. Use
>of transient absorbers is so simple and low cost its perhaps belt and
>suspenders in some cases and the only line of defense in others.
You lost me there. If an alternator is in a runaway condition
and isolated from the aircraft by virtue of an open b-lead contactor
then there is only one load on the alternator's output . . .
field current. Fields are wound with 22AWG wire or smaller. A
14V alternator has a field resistance of about 4 ohms. A runaway
alternator is easily capable of 100 volts divided by 4 ohms
is 25A. Way OVER what the 22AWG wire will carry for more than
a few seconds; way UNDER what the alternator is capable of
generating. This condition has nothing to do with transient
design rules. It does have to do with where energy is being
dissipated in the failed machine. I'm suggesting that the
lion's share of energy produced in all failure modes ends
up in a field winding rated for 50W.
Now, should a battery remain connected to the alternator,
it will do its best to take the alternator's excess output;
the event will be protracted and really messy. The act of
cutting the alternator loose with the intent of allowing it
to self-destruct the field is the intent of the design.
> > We've see the test. There was at least one builder
> > who sent his alternator back for overhaul wherein he
> > failed to provide ANY kind of ov protection and assumed
> > that the alternator had a built in regulator. So through
> > a combination of mis-wiring and poor choice of switch
> > arrangements, he managed to get an alternator on line
> > without a battery or regulator. The alternator didn't
> > even smell really bad. The leadwire between slip ring
> > and field winding had opened like a fusible link. We
> > could probably have spliced it and the alternator would
> > have worked fine.
>
>Incomplete analysis if you did not look for the cause. Your comment on the
>lead wire failure is the result, not the cause and perhaps only a secondary
>result.
We were told the cause. Full bus voltage applied to an externally
regulated alternator. Battery switch ON, Alternator switch ON,
start engine, too much voltage. Battery switch got turned off
but the alternator did not, voltage went much higher. By the
time he recognized that the alternator switch was still on
and reacted to it, the event was over. Field wire fused.
>Also that is only an example of one from one mfgr.
>
>Regardless we are both entitled to our opinions and I am unwilling to take
>even a remote chance when the solution is clearly available and easy to do.
>
>I feel that not disconnecting the field for at least your stated 10 seconds
>is 10 seconds more then is necessary and simply another unnecessary risk.
Risks to what? How much energy is being liberated
and where is it concentrated? If the diodes remain
intact, then ALL power (2500 watts or more) is being
pumped into a field winding designed for 50 watts
max continuous. If certain diodes begin to fail, output
voltage may drop but it still remains much higher than
the rated operating voltage of the field. If the right
combination of diodes fail, output voltage goes to
zero and you get passive shutdown of the runaway.
I've seen schematics for at least one alternator
wherein the manufacturer included a shunt zener and
series fuse in their field wiring. This was similar to
the zener-crowbar ov protection certified onto many
American/Grumman aircraft of years gone by. The notion
here was that during a runaway, the zener would open
the field fuse in a few seconds. FAA agreed
this was adequate ov protection for those aircraft.
I don't recall now which alternator it was . . .
and there may indeed be some in current
production that offer that feature. But without
knowing which ones they are, I have to take the
fallback position of assuming no such feature exists.
Even if it did exist, I've demonstrated many times
that the response time of the fuse/zener combination
for ov protection is longer than the recommended response
times for qualifying ov protection in airplanes.
B-lead disconnect to precipitate timely field failure
(especially on a Lyc where the alternator cruises at
over 10,000 RPM) has what I believe to be a sound
analytical basis.
>Without a Failure Modes and Effects Analysis (FMEA) its risky to base
>conclusions on theory and one example.
An FMEA is an analysis. You said you have analysis that
indicates a hazardous failure mode. I have analysis
that indicates a timely forced failure into a benign outcome.
I have one example of it having occurred in exactly
that way. I'm trying to understand your analysis that
suggests otherwise. How does an 14v alternator field
wound with 22AWG wire maintain continuity for more than the
cited time interval with over 100 volts applied to it?
During this time, which components liberate energy
with so much temperature rise that there is risk of fire?
Bob . . .
Message 27
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| Subject: | Re: ectric-List: |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
If its truly a starved electrolyte, or recombinant gas battery then
there isn't any liquid in it to spill out. Mounting it at any angle
shouldn't be a problem.
Regards,
Matt-
> --> AeroElectric-List message posted by: "Paul Messinger"
> <paulm@tenforward.com>
>
> Many mfgrs include insytructions to not mount that way as the vents can
> then discharge caustic materials.
>
> Concord told me to not even mount on its side.
>
> What ever
>
> Paul
>
>> Mount it in any position. Upside down if you like.
>>
>> Bob . . .
>>
>>
>
>
Message 28
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| Subject: | RE: RG battery mounting positions |
--> AeroElectric-List message posted by: "David Swartzendruber" <dswartzendruber@earthlink.net>
Don Grunke, who is an engineer that works for Concorde Battery out of
their Wichita office, happens to be sitting down the hall from me as I
write. I just asked him about mounting Concorde RG batteries in strange
orientations and he said that on their side is fine. The only reason
they don't recommend upside down mounting is because it's possible that
some liquid could escape through the safety vent if the battery was
overcharged and forced to vent a little. This vent is normally closed
and only opens briefly if the pressure inside the battery becomes too
great.
Dave in Wichita
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com [mailto:owner-
> aeroelectric-list-server@matronics.com] On Behalf Of Matt Prather
> Sent: Thursday, March 13, 2003 2:56 PM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List:
>
> --> AeroElectric-List message posted by: "Matt Prather"
> <mprather@spro.net>
>
> If its truly a starved electrolyte, or recombinant gas battery then
> there isn't any liquid in it to spill out. Mounting it at any angle
> shouldn't be a problem.
>
> Regards,
>
> Matt-
>
>
> > --> AeroElectric-List message posted by: "Paul Messinger"
> > <paulm@tenforward.com>
> >
> > Many mfgrs include insytructions to not mount that way as the vents
can
> > then discharge caustic materials.
> >
> > Concord told me to not even mount on its side.
> >
> > What ever
> >
> > Paul
> >
> >> Mount it in any position. Upside down if you like.
> >>
> >> Bob . . .
> >>
> >>
> >
> >
>
>
>
>
>
>
Message 29
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| Subject: | Re: RG battery operating positions |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 12:23 PM 3/13/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Paul Messinger"
><paulm@tenforward.com>
>
>Many mfgrs include insytructions to not mount that way as the vents can then
>discharge caustic materials.
>
>Concord told me to not even mount on its side.
>
>What ever
>
>Paul
Interesting! I need to ask Skip about this. When the
question came up, the first thought that came to mind
was the Panasonic data sheets for their RG batterier
where we find:
"Panasonic's tough Valve Regulated Lead Acid rechargeable
batteries are designed to provide outstanding performance
in withstanding overcharge, overdischarge, and resisting
vibration and shock. Compact, these batteries save installation
space, while providing full and reliable power. The use of
special sealing epoxies, tongue and groove case and cover
construction, and long-sealing paths for posts and connectors,
assures that the Valve Regulated Lead Acid battery will offer
exceptional leak resistance, and allows them to be used in
any position."
I have several RV-8 builders who have been operating
the 17 a.h. battery on it's side for several years.
The UPS on the desk behind my computer has the battery
standing on the small end. It didn't occur to me
that our friends at Concord might not be able to
sign up to this too.
I'll see what explanation Skip Koss has about
differences in Concord products. Thanks for the
heads up.
Bob . . .
Message 30
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| Subject: | Re: RE: RG battery mounting positions |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:23 PM 3/13/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "David Swartzendruber"
><dswartzendruber@earthlink.net>
>
>Don Grunke, who is an engineer that works for Concorde Battery out of
>their Wichita office, happens to be sitting down the hall from me as I
>write. I just asked him about mounting Concorde RG batteries in strange
>orientations and he said that on their side is fine. The only reason
>they don't recommend upside down mounting is because it's possible that
>some liquid could escape through the safety vent if the battery was
>overcharged and forced to vent a little. This vent is normally closed
>and only opens briefly if the pressure inside the battery becomes too
>great.
>
>Dave in Wichita
Okay . . . that makes sense. Skip told me that their
batteries are 100% saturated which means there IS
a small potential for free liquid that would
be pushed out during an outgassing event.
Bob . . .
Message 31
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| Subject: | Re: Firewall Flange sealant? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:17 AM 3/13/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
>
>
>What's the best thing to use for sealant on the flanges which make up my
>firewall wire penetration - i'm using SS tubing welded to a flange - so
>what would go between the flange and the firewall - to make it
>airtight? I"m not talking about around the wires - but just between the
>flange and firewall? how about proseal - would that be ok -or should it
>be some kind of fireproof silicone - I think someone mentinoed that
>once, I cannot seem to find anything in aircraft spruce - can anyone
>point me in the right direction for of where I might get the correct
>product here?
The installation I posted uses a fire-stop compound. Any
stuff you can find at a builder's supply would probably
be okay here. It's a thin, ideally zero-thickness interface
and about any fire-resistant material is going to be hard
to displace. I suspect silicone sealant would work okay
there too.
Bob . . .
Message 32
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| Subject: | off line for a few days . . . |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
My business expenses credit card awards frequent flyer
miles for cash flow on the card. A few months ago, the
card announced an upcoming re-scheduling of "points"
needed to get a round trip ticket so Dee and I bought
up some tickets to use our present stash at the more
generous rate of exchange.
One set of tickets we bought was to have her folks
join us on a junket to the Pacific NW for a few days.
We'll be leaving in the morning and not be back until
next Wednesday night. I'm not even taking a computer
on this trip to write with.
See you folks Thursday. In the mean time, the older
salts on the list can use this time to exercise
your "learn'n" over the past couple of years.
I WILL have pad and paper . . . need to work on some
new product ideas while in the tender loving care
of the airlines . . . helps keep my blood pressure
down.
Bob . . .
|-------------------------------------------------------|
| The man who does not read good books has no advantage |
| over the man who cannot read them. |
| - Mark Twain |
|-------------------------------------------------------|
Message 33
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| Subject: | Re: 12 vs 28 volts |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:19 AM 3/12/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "Phil Birkelbach"
><phil@petrasoft.net>
>
>What about using a DC-DC converter? I found a bunch of them on Google.
>Here is the search that I did...
>
>http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=dc+to+dc+converter+12
>v+24v
>
>Don't know if there are any drawbacks (noise issues, etc) They seem
>somewhat heavy, and I didn't find any prices so they may cost a mint but it
>would allow you to use a 24VDC radio in a 12VDC system.
>
>Godspeed,
This IS done. My distributor offers several up and down
converters for going each way. On occasion, a builder
has wanted to buy a converter large enough to run all
his radios . . . a high power device who's failure
brings down all radios. Not a really big deal if you
carry flight-bag backups and spend very little time
in clouds.
Bob . . .
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