REFLECTOR: Alternator Field

Sid Knox sbjknox at earthlink.net
Tue Apr 26 19:02:40 CDT 2005


Rene,
I am having to guess how your system is wired, but it seems to me that the Field Breaker doesn't care much about what loads are on the main bus other than of course to vary field current as necessary to maintain your 14 Volt (or whatever) bus voltage.
You report that at one point the alt was charging about 12 Amps.  This is a very modest (and probably typical) current requiring (I am guessing here..) less than 2 Amps of field current.... not enough to pop a good breaker.
So, lacking any more info than was in your message, my guess is:
1)  bad breaker  or 
2)  alternator voltage regulator problem   or
3)  wiring from breaker to field

How to isolate (test for) these?
1)  probably easier to simply replace it.
2)  I don't know how to test for this... not easy, but maybe replace on speculation??
3)  examine and wiggle/gently yank on wiring between breaker and alternator with field energized.

> I feel this may
> be related to my pump not being able to spin with significant slack in
> the gear play causing an electric motor unable to move condition causing
> a high draw condition.

I do not understand what you are saying here....??

Sid Knox
Oklahoma

Velocity    N199RS
Starduster  N666SK
KR2         N24TC
W7QJQ

----- Original Message ----- 
From: "Rene Dugas" <dugasd at bellsouth.net>
To: <reflector at tvbf.org>
Sent: Tuesday, April 26, 2005 6:25 PM
Subject: REFLECTOR: Alternator Field


> Dear fellows,
> 
> I flew from Houston to north Louisiana on  Sunday.  My Alt. Field
> Circuit Breaker opened three times on the flight.  The Vision picked it
> up within 3 seconds.  I pressed it in again and flew without event for
> about 30 minutes and it popped again.  I noticed that the gear pump
> cycled at the same time(yellow motor run light momentarily illuminated).
> I checked the bulbs on the gear indicator and cycled the pump without
> event.  No problems for 20 minutes and it popped again.  Pushed it in
> and continued to charge at usual 12 amps.  Upon landing no problems with
> gear motor running with strobes and pitot heat on at 47 amps.  Checked
> wire to alt. no burns or evidence of short.  I've been told the spring
> in the CB can get weak causing inappropriate opening.  I feel this may
> be related to my pump not being able to spin with significant slack in
> the gear play causing an electric motor unable to move condition causing
> a high draw condition.  Just a feeling.  I am not an EE!  Ideas on order
> of tests or start replacing parts - CB, wiring, Alt., Etc.  Is there a
> condition in the alternator that will cause this and can I check for it?
> I jacked my plane up and my gear will cycle about each 20 to 30 minutes
> which matches the frequency of the problem.  I can not run it on jacks
> to test.  I had the CB open twice before in 250 hrs and reran the wire.
> No problem in over 150 hrs.
> 
> Ideas?
> 
> Rene'
> 
> 
> 
>


--------------------------------------------------------------------------------


> _______________________________________________
> To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
> 
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20050426/4ea78af9/attachment.htm


More information about the Reflector mailing list