Re: Alt Field Circuit Breaker Popping

Corbin Geiser <c_geiser@...>

Success!!  One of the brushes inside the alternator was grounding itself.  Fixed that, installed it and now I’m getting strong voltage and strong amps and the breaker is not popping!!

Now I just need to learn how to adjust throttle to idle....


On Aug 3, 2019, at 12:15 AM, Corbin Geiser c_geiser@... [Q-LIST] <Q-LIST@...> wrote:


Hey Dave - great minds think alike.  I found a guy that is willing to take a look this morning.   I’ll be running it by there to have it tested.


On Aug 2, 2019, at 9:05 PM, Dave Dugas davedq2@... [Q-LIST] <Q-LIST@...> wrote:


This is just a suggestion.....what I would do. If you have a shop near you that can bench test your alternator and repair if necessary, then I would take it there. Up here in Massachusetts there are quite a few. If you can't find a shop near you, you could ship it here and I can take it to someone that does a great job. Seems to me that it would save a lot of time, and either eliminate or confirm a defective alternator. Good luck... Dave D

On Fri, Aug 2, 2019 at 6:13 PM, Corbin Geiser c_geiser@... [Q-LIST]
<Q-LIST@...> wrote:

Mike - forgive me but trying to understand.  When you say A+ are you referring to the Alt field terminal?  Assuming so, if I attach a battery charger to the Alt Field post do I ground to Alt Grnd or engine grnd or does it matter which?  Also, how would the battery charger show any current without the alternator connected to ship power?

Corbin Ge!ser

On August 2, 2019 at 2:57 PM, "q2pilot@... [Q-LIST]" <Q-LIST@...> wrote:


Woa there.  Your Regulator is special.  It has a crowbar circuit.  You did not successfully test the crowbar circuit.  ; 

Here is a way to do that test.  In your airplane, take the big A+ wire off the alternator and apply 14 volts to the A+ wire post on the alternator with a powersupply (battery charger should work).  With the Alternator switch "Off" are you drawing any current from the powersupply?  The answer should be no.  If yes, then your alternator is bad, likely shorted diode.

Next apply 14 volts to the A+ wire that is no longer on the alternator with a powersupply (battery charger should work).  Turn "On" the alternator switch.  The current out of the powersupply should be 0.  If it reads 1 or 2 amps or the 5 Amp breaker blows then your Regulator crowbar circuit is bad.< /div>

Can you take that regulator apart?  It is probably fixable for a lot less $ than a new one.

My money is on the regulator being bad...

Good Luck,
Mike N3QP Q200


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