Bob:
I see that I have stepped in a streaming pile on a path that others have
blazed before me !!!
As for the excellent references, they describe the situation exactly, I
will investigate as you suggest.
Many thanks...
Ed
On Sun, Aug 31, 2008 at 9:22 PM, Robert L. Nuckolls, III <
nuckolls.bob@cox.net> wrote:
> nuckolls.bob@cox.net>
>
> At 06:20 PM 8/31/2008 -0400, you wrote:
>
>> Hello:
>>
>> Been a member for a few weeks now, trying to figure out a problem on a
>> club 172 (building a RV-8).
>>
>> The term "dancing" seems to be applied to what is happening. With light
>> load on (no landing/taxi lights, pitot heat, etc) the ammeter makes a
>> rhythmic swing around the zero point of the meter. I would guess 60-80 times
>> per second. This started a year ago and our A+P says no big deal, at least 3
>> ships at our airport have the same problem!!! With a heavy, full load (turn
>> everything on), ammeter firms right up.
>>
>> I had a nasty alternator/battery failure last november inside the NYC
>> VFR corridor (no place to lose your comm!!!) and replaced alternator +
>> regulator but this problem stills haunts us. We recently swapped the
>> regulator with another, no joy.
>>
>> Ideas on how to proceed?
>>
>
>
> See list-server thread at:
>
> http://tinyurl.com/6fb32p
>
> also top of column 2 on the last page of:
>
>
> http://www.aeroelectric.com/Mfgr_Data/Regulators/Zeftronics/R15V00_Ford_Style_Reulator.pdf
>
> and column 2, third paragraph, page 4 of
>
> http://www.aeroelectric.com/articles/grnding.pdf
>
> It'a a 99% sure deal that if you start with the circuit
> breaker at the bus and replace and/or clean-refurbish
> ALL metallic joints between the bus and the voltage
> regulator, the problem will go away for the twenty+
> years it took for the root cause of the problem to
> build up.
>
> I've never encountered a mechanic that had heard of
> this nor an instructor that included it in his/her
> teachings. The slow build of TOTAL resistance in
> the power path that supplies field current AND
> shares bus voltage sense duties will eventually cause
> ALL airplanes to do this. The Cessnas are the worst
> because of the gross numbers of metallic joints in
> this power path.
>
> Replacing ONE of the many components may cause it
> go reduce or go away leading the observer to believe
> he/she has "slain the dragon". In fact, until all
> the dragons are cleaned out, others will grow to
> sufficient size to become the triggering event.
>
> Metallic joint include those inside the breaker,
> master switch, any OV relays, connector pins,
> and crimps to wires. Each is small but they all
> add up.
>
> An alternative is to replace the stock 'ford' style
> regulator with a more modern device that has a
> separate bus voltage sense wire apart from that
> which carries field current.
>
> Bob . . .
>
>
