belt keeps stopping or turning

While I am driving my 2000 olsmobile silhouette the power steering will stop, the battery sign will come on in my panel. I turn the engine off, raise the hood and ck the belt. It is on and on all of the pulleys. Could the alternator be going out and not turning and in effect stopping the belt completely from turning? I have never seen this happen on any car that I have ever owned. Most of the time when this happens, I can turn the engine off, restart it and it is working fine. I replaced the power steering pump last year so that is working okay. full of fluids. Help!!!

You would do good to check all the components- such as a/c pulley, water pump pulley etc--also see if the tensioner has plenty of stroke and spring to it- sounds like a broken tensioner from here...

I would have to agree with Brcidd, sounds like the belt is loosing tension.

Times 3......I agree on the tensioner.....

If the belts was stopping, it would make noise and smoke like crazy....

Agreed, tensioner bad. When that a/c compressor kicks in it just stalls the belt!