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alternator regulator warning

For the warning see the bottom of this WOB rant...

As some of you may be aware I've been playing with my alternator.  Went
bad a couple of weeks ago.  So I threw in my antediluvian spare with its
noisy bearings while I set about fixing my other one.  Well, of course I
had to screw around and take out *those 4 screws* that hold it
together.  Got all new stainless hardware to reassemble it, had the
housing powder coated, etc, etc.  And of course a new voltage regulator.

I put it in last night.  Didn't work.  Switched back to Mr. Noisy today
to go to my guitar lesson.  Took it apart, took the other one apart,
changed stators, Dremelled off more paint for better grounds, put back
in.  No workee.  Guess I'm staying in tonight.  Buy new alternator
tomorrow?  Oh well.

I just can't stop thinking about it so I sketch out the circuit diagram
of the stupid thing.  Seems the voltage regulator switches the ground to
one brush when the voltage applied to its + terminal is less than about
14v.  Check the one out of Mr. Noisy.  It works.  Take out the one in
the non-charging car.

***I have performed about 3 unnecessary alternator swaps, to say nothing
of destroying a noisy but good back up alternator because of a BAD OUT

words to the wise - test the damn things before installing.  Either
apply 12 v and ground, short the brushes with a test light, it should
light up, or apply juice and carefully measure resistance from the
ground terminal to the top brush.  Should be just a few ohms.  (actually
my good one measured "minus" ohms but who's counting?)

I don't recommend using your car battery for this test, better to use a
one or two amp power supply.  No 400 amp sparks that way.

I'm outta here.

Huw Powell


'82 Audi Coupe "OO oooo OO"