Re: Alternator help needed...1-wire / field wire to batt. stud trick

["Jim Blair" <carnuck@xxxxxxxxxxx>]

Sounds like this was one of the ones that first came out with faulty 
regulators. The dash light that goes on and off with the key (or anything 
adding up to 10 ohms resistance) hooked to the light wire of the alt is 
enough to turn it on and off. Vegas used to only have the dash light to turn 
the alternator on and the dash light would glow with the headlights on. GM's 
answer was to add a resistor behind the dash.


From: farna@xxxxxxx
Subject: Re: Alternator help needed...1-wire / field wire to batt. stud 
trick
To: mail@xxxxxxxxxxxx
Message-ID: <ADVANCES62yfyz5b6KZ000001a6@xxxxxxxxxxxxxxxxxxxxxxx>

Apparently the newer ones have a diode or something preventing feed-back 
through the field wire as you suggested. My car was only driven once every 
2-3 weeks while I was in Korea and never had a problem. But I better check 
and see if the wire is just jumpered or I ran a switched wire to it. I 
remember jumpering it at one point, but but don't remember if I ran it 
differently when I rebuilt the car.


On May 19, 2005 Jerry Casper wrote:

> --- farna@xxxxxxx wrote:
> > An alternator has to have some battery voltage going
> > to it to excite the field before it will charge. A
> > standard Delco alternator can be made into a
> > one-wire by simply attaching the field wire to the
> > battery cable stud on the back of the alternator.
>
>
>  Uh, two things...a single-wire alternator has a
> SELF-exciting regulator, which doesn't require a field
> voltage to get it to start charging, just a higher
> potential from the alternator turning over at a higher
> rpm. THis is NOT the same thing as a standard
> alternator!
>  The OTHER thing is that if you jumper a normal GM
> style alternator Field winding wire to the Battery
> stud, this will cause your battery to discharge more
> quickly over time, as you are keeping a constant ( if
> tiny ) electrical field in the field circuit, and if
> your car sits a couple of weeks, it could be dead by
> then. How do I know? I did this with my '57 Chevy
> years ago, when I upgraded from a generator to an
> alternator, and instead of finding the correct wire
> from the key switch, I just jumpered it. Sure, it
> works...but you will discharge your battery , too. If
> you don't let the car sit for weeks, it's fine, but if
> you go away a few weeks, and come back, dead or low. I
> lived a few hours away from where I stored my car, and
> would only come back on weekends and drive it. If I
> missed a weekend, it'd be 2 weeks. I learned quickly
> that bypassing the shut-off circuit for an alternator
> field circuit wasn't a good idea.
>  "Maybe" the more modern GM alt's are ok with it, but
> they still are NOT 1-wire with self-exciting

> regulator.