Today I pulled out an old stanley belt sander that I bought 5 years ago at my neighbor's moving sale. I plugged it in and it was noisy and sparks were coming from the motor. I tore it apart(it was 5 bucks) and began cleaning out the parts. I noticed that one wire had a bare end, though and it might be shorting out. I have little experience with electric motors, so I'm going to be learning a lot from this project. I hope I don't set my garage on fire.