[V8] Re: Alternators 101 How to How they work

[SuffolkD at aol.com]

Repackaged for easier search: -Scott by BOSTON
> Alternators 101:
> (this applies to almost any modern alternator with an internal regulator)
> 
> The big heavy wire goes directly to the battery and is how the alternator
> charges the battery and powers the cars electrical system. It is the 
> "output" of
> the alternator
> 
> The smaller wire (usually marked "Field") has two purposes:
> 
> First it supplies power (input) to the voltage regulator. When the key is in 
> the
> "on" position you should see battery voltage on this wire.
> 
> Second, it is the "voltage sense" wire. When the motor is running and the
> alternator is working, the alternator will keep the voltage on this input 
> below
> around 13.8 volts. The regulator handles this job so if you have battery 
> voltage
> on the blue wire and the alternator is not charging then you have a bad
> alternator.
> 
> If there is a third wire it is usually for the idiot light or guage.
> 
> There may also be a heavy ground wire.
>