Re: [ihc] alternators

["Ryan Moore" <baradium@xxxxxxxxxxx>]

----- Original Message ----- 
From: <spamaddy@domain.elided>
To: <ihc@domain.elided>
Sent: Thursday, December 02, 2004 20:09
Subject: RE: [ihc] alternators


> I'm using 2 different meters.  One is a cheapo radio shack digital
> multimeter and the other is an analog multimeter where I'm using the
> ohmmeter function.  From looking at the alternator diagram in the book
(I'm
> not an idiot, but I'm not an electronics expert either), the diodes should
> allow juice to flow out from the battery terminal into the system.
However,
> it seems to be going the opposite direction (unless I AM an idiot).
>
> Right now the alt is not installed, it's just wired up and sitting on its
> mounting bracket, so the case is grounded by contact with the bracket.
All
> the accessories are off and there's no cab light or radio feed (hot wires
> that would usually draw current even when the ignition is off).  If I wire
a
> light between the positive battery cable and the positive post on the
> battery it lights up bright.
>
> If I insulate the case of the alternator (put a towel under it as it sits
on
> the bracket) and leave everything else the same, when I hookup the test
> light again it doesn't light up.  So there's no current draw right?
> Everything will still work when turned on, lights, tail lights, and the
> starter will turn over (as it should).
>
> So, based on these conditions it would appear to me that there is a short
in
> the alternator that is allowing the positive feed from the battery (as
> connected from the battery terminal, to the starter, to where the ammeter
> would be, to the alternator battery terminal) to ground out and draw
> current.  Does this make sense?
>
> Ryan, I am confused by what you're suggesting with a test light.  Ugg,
this
> is confusing.
>

It sounds like you're doing it the right way...  and it doesn't sound right
to me either...

I just wasn't sure how you were testing it before.

The ohmeter function won't really work with a diode.  You need to use the
position that looks like a traingle with a line at the pointed end.  That's
the diode test position and will give you a reading *like* ohms, but really
it's the number of volts that it takes to acitivate the diode to get current
flow in the allowed direction.

I suggest taking the thing back out and having the parts store test it.


-Ryan


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