Alternator pulley

[Syndicated]

Im having a problem with an engine i just rebuilt, or more to the point, just the alternator.
Everytime I start the motor, and let it run, even for just 15-20 seconds the alternator pulley gets searing hot, and melts some of the rubber off the belt. At first i thought it was the belt alignment because the alt. pulley wasn't exactly lined up with the water pump. I straightened everything out and it made no difference.
I'm thinking that I've either got it wired wrong or the bearing is blown up - yet it's not making any bad noises and spins relativly easy by hand.

Can anyone offer some insight for me?

Thanks alot
Ben

[Bob]

This may not be much for insight, but how about correct belt. You wouldn't happen to be over tightening it?

If the belt was the wrong size, width wise, it may do a lot of work getting into the groove.

I doubt wiring, because the if you managed to find a way to build heat with incorrect wireing the whole alternator would get hot before the pully. Bearing, maybe, but if your building that kind of heat, you would expect signs of failure like you describe.