Today's Message Index:
----------------------
1. 10:14 AM - Z-13/8 Rev. O questions (John Swartout)
2. 11:07 AM - Re: Wiring run compatabilityWiring run compatability (Larry L. Tompkins, P.E.)
3. 12:39 PM - Do Alternators fight each other on Z-13/8 (JohnInReno)
4. 01:21 PM - Re: Z-13/8 Rev. O questions (Robert L. Nuckolls, III)
5. 01:24 PM - Re: Do Alternators fight each other on Z-13/8 (Hinde, Frank George (Corvallis))
6. 01:36 PM - Re: Re: Avionic's Ground (Robert L. Nuckolls, III)
7. 01:39 PM - Re: Igniton Problem on Rotax 914 - Help (Robert L. Nuckolls, III)
8. 02:15 PM - Re: Flight Test Architecture (Robert L. Nuckolls, III)
9. 02:31 PM - Re: Fuse Sizing (Robert L. Nuckolls, III)
10. 02:36 PM - Re: Nippondenso alternator question (Robert L. Nuckolls, III)
11. 02:37 PM - Re: Nippondenso alternator question (Robert L. Nuckolls, III)
12. 02:43 PM - Re: power to handheld gps. (Robert L. Nuckolls, III)
13. 02:48 PM - Re: power to handheld gps. (Robert L. Nuckolls, III)
14. 02:48 PM - Re: Wiring run compatability (Robert L. Nuckolls, III)
15. 02:55 PM - Re: Do Alternators fight each other on Z-13/8 (Robert L. Nuckolls, III)
16. 03:06 PM - Re: Do Alternators fight each other on Z-13/8 (Matt Prather)
17. 06:18 PM - (bob noffs)
18. 06:50 PM - Re: Nippondenso alternator question (Paul)
19. 07:04 PM - =?ISO-2022-JP?B?GyRCI08bKEJzaGtvc2g=? (Walter Fellows)
20. 08:26 PM - Re: =?ISO-2022-JP?B?GyRCI08bKEJzaGtvc2g=? (Robert L. Nuckolls, III)
21. 08:27 PM - Re: (Robert L. Nuckolls, III)
Message 1
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| Subject: | Z-13/8 Rev. O questions |
Dear Bob,
I note you made several changes to Z-25 Rev. L when incorporating it into Rev.
O of Z-13/8. It would be comforting to know if these are critical changes.
1. The diode between the COM and the + side of the coil terminal of the relay
is gone.
2. The diode between the N.O. and the + side of the coil terminal of the relay
is gone--in fact there is no wire at all between these two terminals now.
3. The resistor attached to the bridge rectifier is now 1K/5W instead of 3K/3W.
4. The resistor across the capacitor terminals is now 1K/5W instead of 1K/3W.
5. The fuselink on the 14AWG wire leading to the battery contactor went from 18AWG
to 20AWG. (I know you maintain the Z-diagrams are intended to show architecture,
not specific wire sizes, but the convention you have stipulated for sizing
fuselinks is four numbers less than the wire size of the protected wire,
not six.)
6. Ground wire from the relay through the Aux Alt Off/On switch went from 20AWG
to 22AWG and the circuit breaker went from 2A to 5A.
Thanks.
John
Message 2
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| Subject: | Re: Wiring run compatabilityWiring run compatability |
Thank you, Frank. It is now a done deal.
The list will probably agree that I've agonized over this long enough.
I did have all my runs separated until the RiteAngle AOA had to change
wings to make room for a heated pitot.
In a few more hours I should be rivetting the lower outboard wing skins
on and then it will be on to the fuselage!
Larry
Message 3
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| Subject: | Do Alternators fight each other on Z-13/8 |
I am wiring an RV9A per Z-13/8 and the certified A/P that is helping with my panel
believes that the two alternators in Z-13/8 will fight each other if they
are ever on at the same time. He also believes that the smaller one will be fried.
I admit that I am not knowledgeable enough to address his concerns. I did
find a reference in the archives to set the voltage lower on the SD-8 if you
want to leave it on all of the time, but that is not my intent.
Can someone help me to address his concern if the 2 alternators are accidentally
both on?
--------
RV-9A - Fuselage
Grumman AA1B-150 (RV-Trainer) Flying
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=192004#192004
Message 4
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| Subject: | Re: Z-13/8 Rev. O questions |
At 01:07 PM 7/9/2008 -0400, you wrote:
><jgswartout@earthlink.net>
>
>Dear Bob,
>
>I note you made several changes to Z-25 Rev. L when incorporating it into
>Rev. O of Z-13/8. It would be comforting to know if these are critical
>changes.
>
>1. The diode between the COM and the + side of the coil terminal of the
>relay is gone.
>
>2. The diode between the N.O. and the + side of the coil terminal of the
>relay is gone--in fact there is no wire at all between these two terminals now.
Those two diodes let you energize the alternator control
relay sourced from either the running alternator -or- a battery.
I neglected to incorporate those in transplanting the Z25 to
Z13/8.
>
>3. The resistor attached to the bridge rectifier is now 1K/5W instead of
>3K/3W.
>
>4. The resistor across the capacitor terminals is now 1K/5W instead of 1K/3W.
Hmmm . . . the 1K vs 3K was a type and either a 3 or 5 watt would do.
I've fixed the values and added a part number for an easy
to find, 3w device.
>
>5. The fuselink on the 14AWG wire leading to the battery contactor went
>from 18AWG to 20AWG. (I know you maintain the Z-diagrams are intended to
>show architecture, not specific wire sizes, but the convention you have
>stipulated for sizing fuselinks is four numbers less than the wire size of
>the protected wire, not six.)
4 or more . . . and in this case, the 20AWG was more
attractive. It will handily carry 10A from the SD8 and
offers about 2x the fusing speed under fault conditions.
>
>6. Ground wire from the relay through the Aux Alt Off/On switch went from
>20AWG to 22AWG and the circuit breaker went from 2A to 5A.
Goofed again. 2A is the correct value for the
smaller wire.
Thanks for the time and attention to review this.
I've made corrections and published revision P
to Z-13/8. Your assistance is valuable and much
appreciated!
Bob . . .
Message 5
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| Subject: | Do Alternators fight each other on Z-13/8 |
Alternators are simply voltage generating devices...They aim to put the regulated
voltage on the buss....If the voltage is less than the required voltage (just
over 14V) it will crank up the current to jack up the volts.
If you have two alternators running its almost certain that will not be exactly
the same regulated voltage so the lower voltage alternator will simply start
backing off on the output current. Eventually you will have one alternator running
the entire load and the other will be backed off to zero amps.
They won't "fight each other" but the non-outputting alternator will still consume
some current in it's field windings so it represents an additional electrical
load.
The SD8 being a permanent magnet device presumably does not consume any current
because it does not have a field winding.
I guee if you have two alternators with exactly the same regulated voltage I guess
it is possible to have each alt taking up the load and then flip flopping
but I would highly doubt that would happen in real life. So no big deal in my
estimation.
Why would you accidently leave them on anyway?..I never switch my SD8 on because
I don't want to risk damaging my Plane power alt by turning it on and off to
test the SD8...So I simply test it at the annual.
Frank
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of JohnInReno
Sent: Wednesday, July 09, 2008 12:34 PM
Subject: AeroElectric-List: Do Alternators fight each other on Z-13/8
--> <john@morgensen.com>
I am wiring an RV9A per Z-13/8 and the certified A/P that is helping with my panel
believes that the two alternators in Z-13/8 will fight each other if they
are ever on at the same time. He also believes that the smaller one will be fried.
I admit that I am not knowledgeable enough to address his concerns. I did
find a reference in the archives to set the voltage lower on the SD-8 if you
want to leave it on all of the time, but that is not my intent.
Can someone help me to address his concern if the 2 alternators are accidentally
both on?
--------
RV-9A - Fuselage
Grumman AA1B-150 (RV-Trainer) Flying
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=192004#192004
Message 6
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| Subject: | Re: Avionic's Ground |
At 07:49 PM 7/6/2008 -0700, you wrote:
><hammer408@comcast.net>
>
>Bob:
>
>I remember during your seminar in Columbus you spoke about using a 20 or 25
>D-Sub and converting it to a Ground system; soldering 2-4 wires on the male
>side and using the female side for connecting various radio stack ground
>pins.
>I can't seem to find this article on your CD-Rom. Can you please search
>your archives and direct me to the site.
You can use the search engine on the website and find two
references at:
http://www.aeroelectric.com/articles/Rev11/18Audio_R11.pdf
http://www.aeroelectric.com/articles/Rev11/AppZ_R11M.pdf
Also check out pictures at:
http://aeroelectric.com/Pictures/Grounding/Minibus1.jpg
http://aeroelectric.com/Pictures/Grounding/Minibus2.jpg
http://aeroelectric.com/Pictures/Grounding/Avionics_Bus_3.jpg
http://aeroelectric.com/Pictures/Grounding/AVG_RA.jpg
http://aeroelectric.com/Pictures/Grounding/AGB_V.jpg
I prefer to use the female side as the
"ground" and male pins running out to the
product. This is because the male pins are
the more fragile . . . they can be accidently
bent and/or broken. EASY to replace if on the
harness side. Damned difficult if on the bus
side.
Bob . . .
Message 7
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| Subject: | Re: Igniton Problem on Rotax 914 - Help |
At 08:55 PM 7/6/2008 -0700, you wrote:
>
>Her is my problem...I have an ACS 510 Keyed switch and Rotax 914 and have
>run the 18 gauge shielded wires from the ignition modules to the switch as
>per Rotax. These are connected to terminal "L" and "R" and other
>connections are as per ACS. When I start the engine and do a mag/ign.
>check, the engine quits when switched to the "R" position. It runs fine
>on "L" and "Both". The shielding is connected to the center ground
>terminal and then grounded at my ground buss.
>
>Can someone tell me what is wrong or give me some ideas? Could I have a
>bad ignition module (they are brand new).
This says the R side is either permanently grounded
and NEVER works or perhaps the module is bad . . . but
I'd sure check the wiring first.
>Also, I know ACS had an AD on their starter solenoids and require a diode
>to be added. I have lost the diode that came with my soleniod so can
>anyone tell me which diode will provide the spike protection (1N5400?) and
>which terminals it connects to.
>
>I hope there is an easy answer to this problem as this is the last thing
>that is keeping my out of the sky.
http://www.aeroelectric.com/articles/spikecatcher.pdf
Check out any of the Z-figures that show how coil suppression
is applied to relays and contactors. In some cases, the suppression
is built right into the contactor (such as the starter contactors
I used to sell) but can always be added externally to the contactor.
Note that for some starter contactors, one side of the contactor
coil is electrically connected to the base of the contactor . . .
so the diode's anode would go to ground, the cathode (banded end
of diode) would go to the contactor coil terminal.
Bob . . .
Message 8
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| Subject: | Re: Flight Test Architecture |
At 11:05 AM 7/7/2008 -0400, you wrote:
>
>
>Good information, Bob, thanks for taking the time to answer my questions
>about electrical system performance. Good point too, that Z-13/8 with a
>big battery back-up is really designed to get you to destination, not just
>back on the ground safely. As I said, "...I would already be headed for
>good weather/divert/home base/whatever if the SD-8 let go" too, but that is
>clearly situationally dependant (the "whatever" clause).
>
>You also said you think a voltmeter indicating SD-8 performance would be
>useful. Are there any schematics/parts recommendations available for that?
>I'd prefer to have the voltmeter on my EDM-900C do double duty depending
>upon which alternator were supplying power to the system, but don't know if
>that is possible or not.
>
>Thanks again for the recommendations.
If you plan to run the EDM-900 from the e-bus, then you're
already covered. Just know that "normal" operations are
expected to be about 0.7 volts lower than actual bus. I.e.,
about 13.5 to 13.9 volts with the alternator set to 14.2 to
14.6 volts. Running the ship's voltmeter from the e-bus allows
for any time testing of the alternate feed path. The
e-bus alternate feed switch can be closed and you'll see
the voltage "jump up" slightly showing that the alternate
feed path is good and the normal feed path diode is good.
If your EDM-900 runs from the main bus, you could
consider a small voltmeter. I've been fiddling with
an expanded scale device (10-15v) meter based on the
same movement as our loadmeter. See:
https://matronics.com/aeroelectric/Catalog/AEC/9007/9007.html
it would have a scale like this:
http://aeroelectric.com/Pictures/Instruments/Expanded_Scale_VM_Proto.jpg
but the overall appearance of the device would match
the loadmeter. I think B&C has a little digital
voltmeter. Also consider:
http://www.egauges.com/vdo_mult3.asp?Type=Voltmeter12&Series=Cyber_Red&Units=E
Bob . . .
Message 9
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At 09:33 AM 7/7/2008 -0400, you wrote:
>
>I just looked through Chapter 10 and didn't find any guidance on
>selecting the size of a fuse.
>I am quite sure that a 10A fuse is designed to blow at, or barely
>above, 10A and thus would be unsuitable for protecting a circuit with
>an actual current flow of 10A.
Fuse ratings can vary a lot from style to style
and application to application for the device. There's
no broad-brush statement one can make about "fuses" . . .
the manufacturer's data is always the best place
to go.
In the case of the ATC plastic devices, the data shows
http://www.egauges.com/vdo_mult3.asp?Type=Voltmeter12&Series=Cyber_Red&Units=E
. . . that you can probablyuse a 10A fuse in a circuit
that draws 10A continuously.
>In my case, I have a landing light circuit totalling 9.2A. Mostly it
>is 4.6A to each bulb, but there are some common wires at the switch
>that carry both loads.
Lamps also have bodacious inrush current. So look for 15A
protection to reduce probability of nuisance tripping.
>Looking at Bob's Wire Size Selection chart with 10C Rise (which makes
>wire selection incredibly easy, compared to the graphs in 43-13-1B), I
>could use 18 gauge wire in the wings and 14 gauge wire where both
>currents are common.
I can't use a double pole switch to wire each light independently with
>separate fuses, because I am already using a double pole switch to
>give me off, on or wig wag.
>
>So I need a single circuit with a single fuse. The fuse needs to be
>sufficient for the total current. This also means upgrading the 18
>gauge wire in the wings to 14 gauge, to avoid having a fuse too big
>for the wire.
Likelihood of incrementally overloading a wire to the
extent that the a 14 AWG wire 'burns' if it happens to
be protected by say a 25A fuse is exceedingly low. The
vast majority of overload faults in DC systems are pretty
hard . . . 10-100 times the ratings of fuses or wires.
Further, wires are quite robust. See:
http://aeroelectric.com/Pictures/Wire/22AWG_20A.pdf
That little strand of 22AWG wire in the picture has
be loaded to 20A for over thirty minutes. Its temperature
rose to only 115C while the insulation was rated for
150C.
>So my gut feel is to use the 35C Rise part of the table to pick a
>current rating for the fuse, which would give me 15A fuse for 14 gauge
>wire. Correct ?
>
>Also, the calculations quite clearly include the return to ground part
>of the current when calculating wire losses due to resistance. What
>equivalent resistance value would be typical of the frame of aluminum
>aircraft when used for the ground return ?
For all practical purposes, your airplane as a ground conductor
has zero ohms resistance. I've measured tip to tail on a Model
400 Beechjet at 0.0012 ohms. I've measured crankcase to battery
minus on a C-172 at 0.008 ohms . . . where virtually all the
resistance came from poor joints in the connectors and wiring.
The airframe itself was under 1 milliohm.
Don't spend a lot of time on it. I'd go with 14AWG throughout
the system and a 15A fuse. If you find that your landing lights
nuisance trip the fuse after x-times of turning them on, then
up-size to a 20A fuse and leave the wires alone. It will
be just fine.
Bob . . .
Message 10
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| Subject: | Re: Nippondenso alternator question |
At 10:35 PM 7/6/2008 -0700, you wrote:
>
>This is my last question...at least for tonight. I have a Rotax 914 and
>the onboard generator is not enough so I added a optional 40 amp
>nippondenso alternator. It has the alt. output and a plug labeled "L" and
>"IG". I assume the "IG" is the field circuit and the "L" is obviously the
>lamp circuit.
>
>The question is this: I have been told that the alt. must have the
>indicator lamp installed for it to charge the battery.
Some do, some don't try it without and if the alternator doesn't come
on line, hook a 100 ohm, 1w resistor between "L" and "IG". The IG
terminal is a control lead only that will tell the alternator to come
on line when +12 is applied to the terminal and assuming the alternator
is spinning. Again, depending on the whims of the designers of the
regulator, REMOVING voltage from IG may or may not turn the alternator
OFF. You'll just have to try it an see how your particular
device operates.
> I don't really want to add another "idiot" light to my panel as I
> already had two for the turbo control unit and one for my GRT EIS. Can I
> run it through the EIS light or will this screw it up? If I have to have
> a light, I may just mount it behind the panel. Lastly, I was told this
> light cannot be an LED...is this also correct?
Use the resistor crimped right into the spade terminals
at the back of the alternator.
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: Nippondenso alternator question |
At 07:17 AM 7/7/2008 -0700, you wrote:
>
>Depends on the specific ND alternator. The ones I have experience with have
>a switch (internal to the regulator) that provides a ground at the "L"
>terminal where (in automobiles) an "Idiot Light" is connected across the "L"
>to the"IG" and indicates the alternator is getting power to the "IG terminal
>but the Alternator's "B" lead Voltage is not high enough to charge the
>battery. The ground is removed (and the light goes out) when the alternator
<snip>
>or bus voltage. The ND alternator generally requires approx 1500 alternator
>RPM to start generation. In an automobile this is generally around the just
>above idle rpm of the engine and again in an auto the idiot light can turn
>on at slow idle and go out just above that rpm.
>
>Paul
There's much good data in this posting . . . enough to give it
some credibility . . . but some absolute errors too. This has
been discussed many times in the past and I won't spend any
more time on it now. Suggest interested readers search the
articles on the website and the archives on the List server.
Disinterested readers should disregard the posting in
its entirety.
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: | Re: power to handheld gps. |
At 10:40 AM 7/7/2008 -0700, you wrote:
>Bob:
>
>My experience is the smallest connectors are ones used in RC aircraft and
>car models. They are sort of a mini Molex connector. I was able to
>obtain then at a local hobby shop.
>
>Hope this helps.
>
Are those the 0.1" spaced devices typical of that which
is supplied with servos? Those are used heavily in the
computer industry and are very useful assembly and
maintenance disconnects. I'd be wary of using them as
a service connection that sees a lot of mate/de-mate
also subject to having their companion wires tugged
on.
Devices typical of this service are:
http://www.molex.com/catalog/pdf/MX70545.pdf
http://www.molex.com/pdm_docs/sd/901560150_sd.pdf
I use a lot of these in my designs INTERNAL to
finished product but wouldn't recommend them
for the wild and wooly world of the airplane
cockpit.
Bob . . .
Message 13
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| Subject: | Re: power to handheld gps. |
At 10:12 PM 7/7/2008 -0400, you wrote:
>Bob Noffs,<?xml:namespace prefix = o ns =
>"urn:schemas-microsoft-com:office:office" />
>
>
>Here are some Radio Shack parts that might work for you:
>
>
>Size N Coaxial DC Power Plug (2-Pack)
>
> $2.99
>
> Model: 274-1573
>
>Catalog #: 274-1573
>
><http://www.radioshack.com/product/index.jsp?productId=2102488&cp=&sr=1&origkw=dc+plug&kw=dc+plug&parentPage=search>http://www.radioshack.com/product/index.jsp?productId=2102488&cp=&sr=1&origkw=dc+plug&kw=dc+plug&parentPage=search
>
>
>Size N Panel-Mount Coaxial DC Power Jack
>
>$2.99
>
>Model: 274-1576
>
>Catalog #: 274-1576
>
><http://www.radioshack.com/product/index.jsp?productId=2102489&cp=&sr=1&origkw=dc+jack&kw=dc+jack&parentPage=search>http://www.radioshack.com/product/index.jsp?productId=2102489&cp=&sr=1&origkw=dc+jack&kw=dc+jack&parentPage=search
>
>
I really thought about adding these to the options
cited on my website but I've had too many problems
with general robustness. They're fine for hooking
wall-warts to your consumer product electro-whizzies
but I think a builder would become dissatisfied with
the choice some time in the future.
Good wire support and engagement retention are
useful in this application. This is my major complaint
about the legacy cigar lighter connectors used on
many automotive accessories. I'm always giving
the connector to my GPS a bit of a push to make
sure it's fully engaged after a few hours of
driving.
Bob . . .
Message 14
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| Subject: | Re: Wiring run compatability |
At 10:59 AM 7/8/2008 -0700, you wrote:
> From previous discussions I believe I'm OK, but want to ask this question
> one last time because I will be closing the wing as soon as the wiring is
> completed.
>
>It looks like I will have to run the RG-58 coax from the wingtip marker
>beacon antenna and the foil shield/drain wire type strobe cable from the
>wingtip strobe in the same conduit. Is that OK? Do I need to do anything
>to ensure a successful outcome from an electrical interference standpoint?
>
No.
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: | Do Alternators fight each other on Z-13/8 |
At 08:20 PM 7/9/2008 +0000, you wrote:
><frank.hinde@hp.com>
>
>Alternators are simply voltage generating devices...They aim to put the
>regulated voltage on the buss....If the voltage is less than the required
>voltage (just over 14V) it will crank up the current to jack up the volts.
>
>If you have two alternators running its almost certain that will not be
>exactly the same regulated voltage so the lower voltage alternator will
>simply start backing off on the output current. Eventually you will have
>one alternator running the entire load and the other will be backed off to
>zero amps.
>
>They won't "fight each other" but the non-outputting alternator will
>still consume some current in it's field windings so it represents an
>additional electrical load.
>
>The SD8 being a permanent magnet device presumably does not consume any
>current because it does not have a field winding.
>
>I guee if you have two alternators with exactly the same regulated voltage
>I guess it is possible to have each alt taking up the load and then flip
>flopping but I would highly doubt that would happen in real life. So no
>big deal in my estimation.
>
>Why would you accidently leave them on anyway?..I never switch my SD8 on
>because I don't want to risk damaging my Plane power alt by turning it on
>and off to test the SD8...So I simply test it at the annual.
Good answer Frank. Basically, the alternator with the
highest voltage setting will assume all system loads up
to and including it's capability after which the votlage
sags until the device with the lower voltage setting picks
up the difference.
There is no risk to either system assuming each is cooled
adequately to assume full rated load. This is the principal
behind Z-12 where both alternators are ON during normal
ops with the 20A machine set 0.5 volts low.
Even when you run dual, identical alternators . . . the
higher setpoint device picks up all load until the
bus voltage sags. They don't get into a dueling alternators
mode in any case.
For Z-13/8, the SD-8 is normally used only when the main
alternator is not functional . . . but it doesn't hurt
it if accidently left on. Just for grins, you COULD set
its regulator about 0.5v below the main alternator but
it's not necessary.
Bob . . .
Message 16
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| Subject: | Do Alternators fight each other on Z-13/8 |
Two comments:
The field current on the unloaded alternator should go to zero - the
regulator will clamp it off because the sensed voltage is above the set
point. There will be a very small amount of current consumed by the
regulator itself - I'd think much less than 1A.
I believe there have been some problems when two alternators share a bus.
It seems I remember hearing that it's related to the time-constant of the
regulator circuit, reactance on the bus, and voltage is sensed. On a
light twin, I think. The bus voltage was unstable if I recall correctly.
I'd guess that two could share a bus safely if the set point of one of the
regulators was a good amount higher than the other - meaning that one of
the alternators is off until bus loads go way-up, or if the primary
alternator fails off.
Regards,
Matt-
> <frank.hinde@hp.com>
>
> Alternators are simply voltage generating devices...They aim to put the
> regulated voltage on the buss....If the voltage is less than the required
> voltage (just over 14V) it will crank up the current to jack up the volts.
>
> If you have two alternators running its almost certain that will not be
> exactly the same regulated voltage so the lower voltage alternator will
> simply start backing off on the output current. Eventually you will have
> one alternator running the entire load and the other will be backed off to
> zero amps.
>
> They won't "fight each other" but the non-outputting alternator will
> still consume some current in it's field windings so it represents an
> additional electrical load.
>
> The SD8 being a permanent magnet device presumably does not consume any
> current because it does not have a field winding.
>
> I guee if you have two alternators with exactly the same regulated voltage
> I guess it is possible to have each alt taking up the load and then flip
> flopping but I would highly doubt that would happen in real life. So no
> big deal in my estimation.
>
> Why would you accidently leave them on anyway?..I never switch my SD8 on
> because I don't want to risk damaging my Plane power alt by turning it on
> and off to test the SD8...So I simply test it at the annual.
>
> Frank
>
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
> JohnInReno
> Sent: Wednesday, July 09, 2008 12:34 PM
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: Do Alternators fight each other on Z-13/8
>
> --> <john@morgensen.com>
>
> I am wiring an RV9A per Z-13/8 and the certified A/P that is helping with
> my panel believes that the two alternators in Z-13/8 will fight each other
> if they are ever on at the same time. He also believes that the smaller
> one will be fried. I admit that I am not knowledgeable enough to address
> his concerns. I did find a reference in the archives to set the voltage
> lower on the SD-8 if you want to leave it on all of the time, but that is
> not my intent.
>
> Can someone help me to address his concern if the 2 alternators are
> accidentally both on?
>
> --------
> RV-9A - Fuselage
> Grumman AA1B-150 (RV-Trainer) Flying
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=192004#192004
>
>
Message 17
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hi all,
bob n. often refers us to a site that has great pics and instructions.
for example how to make a pigtail on a shielded wire and attach to a
wire. is there a web site i can go to that has all these how to do's in
an index?
thanks, bob noffs
Message 18
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| Subject: | Re: Nippondenso alternator question |
I agree that its been much discussed in the past however there are many
false and remaining incorrect mis stated comments in the past that simply do
not apply to the most common ND alternator. These false statements remain in
the past unchallenged but still remain not correct with respect to ND
alternators.
Other than MY having tested many ND alternators as well as a couple of other
brands of Internally regulated Japan brand alternators .I question your
accusation that I have made absolute errors (or any errors of any sort) in
my statements.
For example, all the ND alternators I have tested can be turned on and off
while running and producing power. They also can be "B" lead disconnected
under load with no damage to the alternator IF the alternator contacts are
rated properly ( the common often used contactor are not rated to disconnect
the load dump voltages). The addition of the proper contact voltage and
proper power rated transorb is required to protect any low voltage contactor
from arcing and passing the higher load dump voltage back to the bus. The
subject alternators have internal transorbs but may overheat under the long
contact bounce of the common contactor, in particular if that contactor has
a diode across the coil which extends the opening or the contact from around
5ms to as long as 50 ms with, in several cases, major arcing of dozens of
arc pulses. Using the industry recommended transorb across the contactor
coil minimizes the arcing and opening delay but does not resolve the contact
voltage rating which is overstressed and demonstrated to arc during my
testing. Its one of the repeatable tests that ranged from 2 amps to 40 amps
load
I have performed 100's of repeatable tests to support the analysis of the
above statements including the contact arcing under load of the common
contactor.. As well as fast opening and lack of arcing with the Kilovac in
"B" lead testing
My findings include ND alternators commonly used at the time by NSI, Vans
and others in the mid 1990's have the following features.
1. The IG terminal turns on and off the alternator under load.
Note Its safe as far as the alternator is concerned to turn off the
alternator under load. It must be done with properly rated contactors
however.
2, I have been unable to cause alternator failure even with arcing "B" lead
contactor. Both NSI and Vans at the time was selling rebuilt alternators and
Vans told customers not to use any type of "B" lead crowbar device due to
alternator failure.
Note: This I verified with a personal phone call at the time to Vans. I have
no evidence to suggest your OVP crowbar was the cause but I do suspect the
common contactor was a possible cause due to observed excessive contact
arcing during the extended opening of the contacts due in part to the simple
diode used and the contactor contact V rating.
3. No ND I tested locked up and could not be turned off at any time safely.
4. No ND required anything connected to the "L" terminal.
Clearly its not possible to test all of the hundreds of types of small shell
ND alternators. Further rebuilt alternators may have internal regulators
with difference performance as our application has the alternator wired
differently and the aftermarket rebuilt alternators may have regulators that
only work when installed in an automobile as the original application.
5. Its safe to open the "B" lead under load if the contactor is rated for at
least 200V contact rating. Only the KIlovac and similar HV contactors have
proper voltage ratings. The common contractors for 12V system battery and
starter etc have contacts only rated for under 50V max during the opening
process. They can tolerate higher voltage across the contacts when the
contacts are open. They will arc during the opening of an alternator load
and the result may cause damage to both the alternator and aircraft bus.
Do not use a common diode across a common contactor coil and do not use a
common 45V contactor contact rating as either or both actions greatly
increase of alternator damage
Perhaps you can substantiate your statements with some of your testing of
the commonly used ND alternator. Please provide the Lester number so we all
can verify your test results.
My reply to the questioner was intended to be general as he did not state
the exact ND Lester number and was it rebuilt or new. With out knowing that
there is no absolute recommendation on how to wire it up
Yes there are alternators of different brands (and perhaps some ND do also,
but not the common ones that I have tested.) that lock up and others that
require a lamp in the wiring to start. perhaps there are also other that
cannot survive a load dump but none in the industry will state that their
regulators lack the universal load dump internal protection (except that
load dumps resulting form extended arcing from contacts or broken wiring are
not protected as overheating or the protection Transorb is possible.
Your cheep un-substantiated comment that I have made absolute errors does
not suit your normally nice style. Lets keep the discussion technical and
not call me a person making false statements please.
No respectable person can let that cheep shot pass. If I made a error please
prove it. How many stock ND alternators used in aircraft have you tested????
Perhaps I missed it in the past and if so I apologize if you show me the
statement. It has been more than 10 years ago when many of my testing was
done and perhaps My memory has failed. To me the discussion on this years
ago was long settled with you on one side and Jet Pilot George (for one) on
the other side.
As side comment many regulators have a OVP built in that limits the output
voltage to around 16V. This will not protect against all failures thus an
external OVP is required. I have experienced 2 regulator failures (over the
past 50 years in autos where the output jumped from 14+ to 16V and held the
output there. One was the common external regulatro YOU long have
recommended as a low cost "ford" style.
Please do not reply and waste bandwidth and all of our time unless you have
specific test data to prove your response. Past history posts that do not
include backed up with actual testing ase just opinion and not worth
considering.
Paul
PS: I do not want to start another often widening discussion. Perhaps I
should have remained silent but you stated you were out of town and I have
had a lot of experience including some from other groups (who in error) make
general statements that ND alternators require a light across the IG and L
connections. Further I have had the impression you have yet to test any
internal ND or any other brand alternator. This was to be done after you had
the test stand up and running.
I have witnessed and peer reviewed test setup and test results to support
the above statements. Only the conclusions have ever been document as I felt
at the time there was no reason to do more than I did. I simply am not
interested in trying to prove anything to anything just pass on real test
results that proved how the auto internal reg alternator can be safely used.
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckolls.bob@cox.net>
Sent: Wednesday, July 09, 2008 2:33 PM
Subject: Re: AeroElectric-List: Nippondenso alternator question
> <nuckolls.bob@cox.net>
>
> At 07:17 AM 7/7/2008 -0700, you wrote:
>
> There's much good data in this posting . . . enough to give it
> some credibility . . . but some absolute errors too. This has
> been discussed many times in the past and I won't spend any
> more time on it now. Suggest interested readers search the
> articles on the website and the archives on the List server.
>
> Disinterested readers should disregard the posting in
> its entirety.
>
> Bob . . .
>
> ----------------------------------------)
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ----------------------------------------
>
>
>
Message 19
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| Subject: | =?ISO-2022-JP?B?GyRCI08bKEJzaGtvc2g=? |
$B#B(Bob
$B#I(B didn't find you on the forum list, will you be at $B#O#S#H(B and if so,
how
do we find you?
$B#B(Best $B#R(Begards
$B#W(Balter $B#F(Bellows
Message 20
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| Subject: | Re: =?ISO-2022-JP?B?GyRCI08bKEJzaGtvc2g=? |
At 06:59 PM 7/9/2008 -0700, you wrote:
><walter.fellows@gmail.com>
>
>$B#B(Bob
>
>$B#I(B didn't find you on the forum list, will you be at $B#O#S#H(B and if
>so, how
>do we find you?
>
>$B#B(Best $B#R(Begards
>$B#W(Balter $B#F(Bellows
Walter, your message came through a bit scrambled,
I think you were asking if we were going to be at
Oshkosh this year. Unfortunately no. My present work
load and other commitments won't support it. We
will be there next year and I'll try to sign up
for a couple of forums.
Bob . . .
Message 21
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At 08:13 PM 7/9/2008 -0500, you wrote:
>hi all,
> bob n. often refers us to a site that has great pics and instructions.
> for example how to make a pigtail on a shielded wire and attach to a
> wire. is there a web site i can go to that has all these how to do's in
> an index?
> thanks, bob noffs
http://aeroelectric.com
No real good index yet, that's being worked on. But there
is a Google search engine link that searches only the
AeroElectric Connection website on words and phrases
of interest.
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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