I have one of these (http://www.goldmine-elec-products.com/prodinfo.asp?number=G17949) motors connected to an H-bridge. It's part of a pulley system that lowers an object up and down on a string. It lowers the object down just fine; however, whenever I try to lift it back up again, the object gets stuck very easily, and lately the motor has begun to make a strange noise that I instinctively sense it should not be making.
Does anybody have any clue why? I'm running it off of the 5v supplied by the arduino.