Today's Message Index:
----------------------
1. 10:09 AM - Re: home wiring ground faults (GLEN MATEJCEK)
2. 11:42 AM - Re: alternator whine (Alec Myers)
3. 12:34 PM - Re: IR Alternator Voltage (eschlanser)
4. 04:34 PM - Re: alternator whine (Robert L. Nuckolls, III)
5. 04:47 PM - Re: Re: IR Alternator Voltage (Robert L. Nuckolls, III)
6. 04:50 PM - Re: alternator whine (Alec Myers)
Message 1
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| Subject: | Re: home wiring ground faults |
I've seen two pertinent miswirings. One is having the ground and neutral
connected together in a sub panel. The other was putting one gfci
downstream of another. Both caused nuisance trips. The first scenario is
actually not uncommon with hot tubs. All is well until the light is turned
on, and then the gfci trips. The second was a unique situation, and didn't
manifest issues until years after the installation.
Ymmv, few, yada yada...
Message 2
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| Subject: | Re: alternator whine |
I did a little investigation yesterday -
No aircraft control affects the volume, except the volume control
directly on my headset. Even turning up the panel intercom volume
doesn=99t make any difference.
> On Oct 6, 2017, at 10:30 AM, Robert L. Nuckolls, III
<nuckolls.bob@aeroelectric.com> wrote:
>
> At 08:37 PM 10/5/2017, you wrote:
<alec@alecmyers.com>
>>
>> Hi Bob and others,
>>
>> My 182 has a noticeable alternator whine, about 5kHz (I=C3=A2=C2=C2=99
m guessing) at cruise rpm. I think it=C3=A2=C2=C2=99s worse recently
than it used to be.
>>
>> Where and what should I start investigating?
>
> Does operation of any audio panel selector
> switch or setting of any radio or audio
> system volume control have an effect on
> the perceived noise?
>
>
> Bob . . .
>
Message 3
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| Subject: | Re: IR Alternator Voltage |
> Sorry, I don't have the model specifics with me (can get later) but off
> the top are there ways to adjust the output of IR type alternators or is
> that a factory setting that cannot be changed? Is this an "it depends"
> item?
>
>
> Probably not. I've never seen an adjustable regulator on
> an internally regulated machine. In fact, most external
> regulators were not adjustable either.
> Before you take a wrench to the airplane, check the
> alternator output voltage at the alternator's b-terminal.
> The internal regulator senses b-terminal voltage and
> there MAY be a difference. You can probably buy a
> replacement regulator but depending on the alternator,
> it might be lest hassle/expense to trade it in.
>
>
> Bob . . .
[/quote]
I'm having the same need as the OP. That is, low displayed voltage from my IR alternator.
I understand the directions but do not know how to implement them on
a running airplane. This may be an electric 101 question. How do I physically
check the alternator output voltage at the alternator's b-terminal? I don't
have anyone willing to reach in and hold the voltmeter test leads on a running
airplane.
Eric
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=473408#473408
Message 4
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| Subject: | Re: alternator whine |
At 01:40 PM 10/7/2017, you wrote:
>I did a little investigation yesterday -
>No aircraft control affects the volume, except
>the volume control directly on my headset. Even
>turning up the panel intercom volume doesn=99t make any difference.
Aha! Good data.
check to see if your headset jacks are grounded
to airframe locally. Depending on age of your Cessna,
that could have been standard practice at the factory.
If grounded locally, mount the jack on an insulating
washer and run a ground wire all the way back to
the radio grounds. You may find that there already
is a ground wire but no washer . . . in which case
adding the washer is likely to fix it.
Bob . . .
Message 5
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| Subject: | Re: IR Alternator Voltage |
>
>
>I'm having the same need as the OP. That is, low displayed voltage
>from my IR alternator. I understand the directions but do not know
>how to implement them on a running airplane. This may be an electric
>101 question. How do I physically check the alternator output
>voltage at the alternator's b-terminal? I don't have anyone willing
>to reach in and hold the voltmeter test leads on a running airplane.
>
>
>Eric
Easy, don't PROBE the points of interest, CLIP them.
I very seldom use 'probes' for any measurement, virtually
all signals of interest need to be sampled while your
hands are fully occupied with other tasks.
Emacs!
I have several dozen clip leads sets in the various
tool boxes and workbenches. As a general rule, I make
them up with a minimum 36" long. I have a couple of
sets that are 10' long. I once built a special clip
set about 40' long to watch a voltage in the 'hell hole'
of a Beechjet whilst I was fiddling with knobs in
the cockpit.
Built yourself a 10' pair. Clip to points of interest
under the cowl then sit in the cockpit taking voltage
readings ar various rpm and loads. Tape the leads
to under side of cowl to keep prop wash from shaking
the wires so bad that it pulls the clips off . . .
been there, done that.
Bob . . .
Message 6
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| Subject: | Re: alternator whine |
Awesome. I=99ll give it a try, and report back.
On Oct 7, 2017, at 19:33, Robert L. Nuckolls, III <nuckolls.bob@aeroelectric
.com> wrote:
At 01:40 PM 10/7/2017, you wrote:
> I did a little investigation yesterday -
> No aircraft control affects the volume, except the volume control directly
on my headset. Even turning up the panel intercom volume doesn=99t ma
ke any difference.
Aha! Good data.
check to see if your headset jacks are grounded
to airframe locally. Depending on age of your Cessna,
that could have been standard practice at the factory.
If grounded locally, mount the jack on an insulating
washer and run a ground wire all the way back to
the radio grounds. You may find that there already
is a ground wire but no washer . . . in which case
adding the washer is likely to fix it.
Bob . . .
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