Today's Message Index:
----------------------
1. 02:07 AM - Re: Alternator Ground (David and Elaine Lamphere)
2. 04:38 AM - Re: Alternator Ground (Alec Myers)
3. 08:13 AM - Re: Alternator rectifier bad? (Robert L. Nuckolls, III)
4. 08:16 AM - Re: Alternator Ground (Robert L. Nuckolls, III)
5. 08:52 AM - Re: Alternator rectifier bad? (pjc)
6. 09:34 AM - Re: Alternator Ground (Jeff Luckey)
7. 01:26 PM - Re: Alternator Ground (rparigoris)
8. 04:42 PM - Re: RV10 Electrical Issue (w/ Format Clean Up) (user9253)
9. 05:36 PM - Re: Re: RV10 Electrical Issue (w/ Format Clean Up) (WILLIAM BOOTH)
10. 06:39 PM - Re: RV10 Electrical Issue (w/ Format Clean Up) (user9253)
11. 09:49 PM - Re: Re: Alternator Ground (Bob Verwey)
Message 1
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| Subject: | Re: Alternator Ground |
Thats one I actually think I can answer!
The ground is through the alternators chassis, mount, engine case and ground strap
from engine to firewall ground terminal.
Thats why having a good ground connection to the engine is important.
Dave
On Jan 13, 2021, at 10:26 PM, Dan <limadelta@gmail.com> wrote:
I have a Continental IO 550 with a Kelly 70 amp 12 volt alternator. The wiring
diagram shows two field terminal posts (F1 and F2), a positive terminal, and
an "AUX" terminal. It does not show a ground. Any idea how this alternator is
supposed to be wired to ground? See attached pic.
Thanks,
Dan
<Alternator pic.pdf>
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| Subject: | Re: Alternator Ground |
Ground is through the metal frame of the alternator, bolted to the engine, no?
On Jan 13, 2021, at 22:32, Dan <limadelta@gmail.com> wrote:
I have a Continental IO 550 with a Kelly 70 amp 12 volt alternator. The wiring
diagram shows two field terminal posts (F1 and F2), a positive terminal, and
an "AUX" terminal. It does not show a ground. Any idea how this alternator is
supposed to be wired to ground? See attached pic.
Thanks,
Dan
<Alternator pic.pdf>
Message 3
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| Subject: | Re: Alternator rectifier bad? |
At 10:06 PM 1/13/2021, you wrote:
>
>I have an automotive alternator (14184, external ford=9D regulator) that
has
>given good service in my RV6. Recently I have noticed fluctuating voltage
>displayed (digitally) on the USB adapter plugged into a 12V power socket
>(cigarette lighter style).
Fluctuating voltage from an alternator is almost
never caused by a failure in the power-output
components (stator wiring and rectifier); it's
almost always caused by some anomaly in the
excitation/regulation side of the house. Regulator,
field supply power path, brushes, etc.
>Investigating further I see about 2V (RMS) on the bus with my cheapie
>nultimeter when the alternator is running and measure 14V (fluctuating
>+2/-0.5) with the meter on DC.
The output from an alternator is trashy. 3-phase, rectified
power has a built-in peak to peak ripple on the order of
13%. So a 14vdc machine can be expected to come with ~2
volts peak-to-peak ripple. There are test tools intended to
diagnose an abnormal increase in this value as a result
of rectifier failure. An open or shorted diode in a
rectifier will produce a marked increase in ripple
voltage.
Multimeters have varying ability to quantify this
voltage. There's pk-pk, average, rms, etc. Then
there are vagaries in the AC to DC conversion
techniques that the meter ultimately tries to
interpret and display. Some are better at it than
others but unless you have a BENCHMARK ac voltage
reading for a known good alternator, interpreting
the readings you've observed is problematic.
> I imagine this isn=99t doing any good for my Odyssey PC680.
The battery couldn't care less.
>I=99m thinking I have a blown diode in the rectifier.
Unlikely.
> Any chance the regulator could be to blame? Any further diagnostics
> called for before buying a replacement (rebuilt) alternator at the
> auto parts place ($35) ? Any place to find a replacement rectifier
> to install in the otherwise still functioning alternator?
You bet! "Ford" regulators (an those with similar
architecture) are 'hyper sensitive' to increases
in resistance in the field-supply/voltage-sense
pathway.
See the narrative in this document
http://www.aeroelectric.com/articles/Alternators/Know_Your_Charging_System.p
df
That starts on page 8 under, "Battery Master Switch and Battery
Master Relay"
This phenomenon described has often been called
"the galloping/dancing ammeter syndrome". In your case,
it may be the "galloping voltmeter syndrome".
Given the age of your airplane and the 'ford'
regulator, there's a high probability that
your difficulty has roots in this same cause.
(do a Google on "dancing ammeter" and "galloping
ammeter" for a look back in time for this
condition.
Start by fabricating a jumper wire to run
from your regulator A and B terminals directly
to the alternator B terminal thus bypassing ALL
at-risk wiring. Fire the engine up and check
voltage NOTE: THE ALTERNATOR COMES ON LINE
IMMEDIATELY AS FOR AS LONG AS THE ENGINE IS
RUNNING.
If the voltage becomes stable, then consider
renewing ALL components between the bus and
the regulator A and B terminals. Replacing
one item might 'fix' the problem but renewing
all the components comes closer to effecting
a fix good for another 10 years.
To rule out a regulator failure, you can
use a known good regulator to fabricate
the test-tool shown and wire it to the back
of your alternator for a test fun.
This is a problem that has plagued a constellation
of older, single engine aircraft. We've had lengthy
discussions on the List and elsewhere on the 'net.
>As to causes, I am guilty of powering the field
>on and off a couple of times while the engine
>was running. This was in effort to diagnose a
>headphone noise (probably originating from the
>electro-mechanical regulator switching). I have
>subsequently been told powering the field on/off
>while running is a =9Ca bad idea=9D.
Contrary to popular myths, that has no deleterious
effect on the system or its components.
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 4
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| Subject: | Re: Alternator Ground |
At 04:03 AM 1/14/2021, you wrote:
>and Elaine Lamphere <dalamphere@comcast.net>
>
>That=99s one I actually think I can answer!
>The ground is through the alternator=99s
>chassis, mount, engine case and ground strap
>from engine to firewall ground terminal.
>
>That=99s why having a good ground connection to the engine is
important.
>
>Dave
Correct. Both starter and alternator seek
ground through their attachments to the
engine. That fat/flexible jumper from
crankcase to firewall ground stud is
really important.
Further, this alternator has a 2-terminal
field connection. One of those terminals
should be grounded to alternator case.
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 5
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| Subject: | Re: Alternator rectifier bad? |
Bob,
Thanks for the informative and comprehensive response.
I have enjoyed the dancing ammeter (but without observing the voltage fluctuations)
for as long as I have been operating this a/c. I assumed it was normal for
the old style regulators.
I have work to do, and will report back!
Peter
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=500226#500226
Message 6
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| Subject: | Re: Alternator Ground |
Hey Bob,
I have 2 questions:
1. Is the reason that some alternators surface both ends of the field so th
at the end user can select either an A-Circuit or B-Circuit regulator?=C2
- (Thus giving the user more regulator choices.)
If so, then your advice:
"Further, this alternator has a 2-terminal
=C2- field connection. One of those terminals
=C2- should be grounded to alternator case. "
would only apply to an B-Circuit regulator.
2.=C2- Is that correct?
I seem to remember working on some big Leece Neville alternators (read big
& expensive) where both sides of the field were available but don't remembe
r what regulators were used (that was decades ago).
3. Are you aware of any automotive vehicles where they used and alternator
with both side of the field exposed?=C2- ( I imagine not since in the aut
omotive world it's all about cost)
-Jeff
On Thursday, January 14, 2021, 08:25:35 AM PST, Robert L. Nuckolls, III
<nuckolls.bob@aeroelectric.com> wrote:
At 04:03 AM 1/14/2021, you wrote:
--> AeroElectric-List messageposted by: David and Elaine Lamphere<dalampher
e@comcast.net>
That=C3=A2=82=AC=84=A2s one I actually think I can answer!
The ground is through the alternator=C3=A2=82=AC=84=A2s chassis, moun
t, engine case andground strap from engine to firewall ground terminal.
That=C3=A2=82=AC=84=A2s why having a good ground connection to the en
gine isimportant.
Dave
=C2- Correct. Both starter and alternator seek
=C2- ground through their attachments to the
=C2- engine. That fat/flexible jumper from
=C2- crankcase to firewall ground stud is
=C2- really important.
=C2- Further, this alternator has a 2-terminal
=C2- field connection. One of those terminals
=C2- should be grounded to alternator case.
=C2- Bob . . .
=C2- Un impeachable logic: George Carlin asked, "If blackboxes
=C2- survive crashes, why don't they make the whole airplane
=C2- out of that stuff?"
Message 7
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| Subject: | Re: Alternator Ground |
Hi Group I helped a friend a number of years ago chase down cause of a flaky alternator
output on his V-Tail Bonanza. He recently had a Major. A&P changed regulator.
Owner took alternator to a car parts place and had alternator tested
and all was well? When I looked at alternator it looked beautiful, it was newly
painted. I tried to tighten the two halves of the alternator together and things
were not tremendously tight. This was after a flight when things were hot.
I was able to put my thumbnail into the new paint and it was thicker than I
think it should have been. I loosened halves, pulled apart enough to clean of
paint between halves and re tightened. Problem was paint was insulating connection
of 2 halves of alternator. Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=500232#500232
Message 8
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| Subject: | Re: RV10 Electrical Issue (w/ Format Clean Up) |
I redrew part of the RV-10 electrical drawing from post #1 to make it easier to
read.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=500235#500235
Attachments:
http://forums.matronics.com//files/rv_10_209.png
Message 9
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| Subject: | Re: RV10 Electrical Issue (w/ Format Clean Up) |
Thanks again Joe. Im soaking this up as best I can. To me it simplifies the system.
I need to research how to read the relay symbology. The relay on the aux batteries:
I assume that as long as there is power to the main buses the relay is open
but if that power were to fail it closes and provides power from the aux batteries
to the essential bus.
William Booth
> On Jan 14, 2021, at 7:43 PM, user9253 <fransew@gmail.com> wrote:
>
>
> I redrew part of the RV-10 electrical drawing from post #1 to make it easier
to read.
>
> --------
> Joe Gores
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=500235#500235
>
>
>
>
> Attachments:
>
> http://forums.matronics.com//files/rv_10_209.png
>
>
>
Message 10
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| Subject: | Re: RV10 Electrical Issue (w/ Format Clean Up) |
I do not think that the aux battery relay automatically switches on if needed.
It is hard to tell because the drawing is blurry.
But it looks like Bus B switch must be turned on to energize the relay.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=500240#500240
Message 11
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| Subject: | Re: Alternator Ground |
Very interesting !
On Thu, 14 Jan 2021, 23:30 rparigoris, <rparigor@hotmail.com> wrote:
> rparigor@hotmail.com>
>
> Hi Group I helped a friend a number of years ago chase down cause of a
> flaky alternator output on his V-Tail Bonanza. He recently had a Major. A&P
> changed regulator. Owner took alternator to a car parts place and had
> alternator tested and all was well? When I looked at alternator it looked
> beautiful, it was newly painted. I tried to tighten the two halves of the
> alternator together and things were not tremendously tight. This was after
> a flight when things were hot. I was able to put my thumbnail into the new
> paint and it was thicker than I think it should have been. I loosened
> halves, pulled apart enough to clean of paint between halves and re
> tightened. Problem was paint was insulating connection of 2 halves of
> alternator. Ron P.
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=500232#500232
>
>
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