Keep blowing 15amp Alternater Charging circuit Fuse

I have a weird problem I cannot seem to rectify. My 1996 explorer (5.0 litre) keeps blowing the charging circuit fuse. I checked the alternator and I am getting 14.+ volts while running. The problem is when I put it in drive and the rpm lowers slightly it blows the 15amp fuse under the hood in the power box and my charge light comes on. It also does not always happen right away. Sometimes I have driven for 30 to 40 minutes before my battery charge light comes on. The alternator bearing seems to be making noise however I assumed that if the alternator where defective it would't charge at all. I am at a complete loss over this one. Can anyone help?

alternators can go bad from a number of things. sounds like it was overheated and the insulation on the windings are shorting out. u might wana take it to autozone or a parts store and have it tested. also, do u have a stereo with amps and subs hooked up? that might be to much for it

alternators can go bad from a number of things. sounds like it was overheated and the insulation on the windings are shorting out. u might wana take it to autozone or a parts store and have it tested. also, do u have a stereo with amps and subs hooked up? that might be to much for it

Thanks, I think the alternator is bad. As I mentioned, the bearing is making a loud noise as well. I was just confused that it would not happen all the time right away however now the fuses blow immediately. I am going to remove and replace the alternator. Will post the results. Thanks for responding.