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Re: Mark I, Now '73 B Alternator

To:, mgs@Autox.Team.Net
Subject: Re: Mark I, Now '73 B Alternator
From: RJohn50603 <>
Date: Fri, 10 Apr 1998 06:50:01 EDT
In a message dated 98-04-09 17:42:03 EDT, writes:

<< This is interesting, and brings up a good point. I just thought it was
 normal for me to lose voltage while idling at around 900 rpm on my old
 "dynamo". I don't have a stereo, so the only thing noticable is the blinkers
 slowing and dim lights. I also assumed it was a generator and not an
 alternator, but now that I've looked at the Haynes it seems all neg earth
 cars had alternators. Now I'm confused. It's probably the original part,
 still holding its own except for these symptoms.
 I seek the wisdom of the list...any thoughts on my (more than likely) '73
 dynamo? Replace the brushes? I did this once on my VW bug (generator), but
 I've learned my toy is a different B-reed altogether!
 '73 B >>


I think you need to temporarily wire in an amp meter to solve the mystery.
Leave the lights on awhile with the engine off, start the engine and turn
everything electrical on. I believe the standard alternator is capable of
about 34 amps output. You should see something close to this on the ampmeter,
assuming your battery(s) are in good shape.

Besides the brushes being worn, there is the possibility that one or more of
the diodes might be open, reducing the output proportionately. There's nine of
them in there in groups of three. If the output is low by 1/3 or 2/3's, that
would make a good case to suspect them. The internal voltage regulator could
be off as well. Then, there are things such as bad connections, stator
windings, etc.

I believe you can buy the diodes and the internal regulator through Moss if
you want to fix it rather than replace it.

R. Johnson - Dallas

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