3G alternator getting too hot!?

ttt... man im starting to think its my second bad alternator in a row. That or something is wrong with my car! I let it idle up to temp and you cant put your hand on the case for more than couple seconds. Im positive my wiring is right, i added the extra ground from the block to the frame....and its my second alternator from the same place. I really dont want to buy a third alternator and have it overheat too. Anyone have any ideas?

The volt guage checks out fine, over half way mark. I really dont want to even drive it because im afraid i will cook this alternator. I bet thats how my first one went out too. Why does my car overheat alternators!?!?

yea i dont know that its overheating, but five minutes after a cold start and you cant even touch it. I dont ever remember my stock one being this hot, or the alt on my truck, or anything.