|It's overheating under load; in other words, when the motor is having to actually do some work, rather than just freewheel. That's a typical failure mode for motors. As for why, it's due to loss of magnetic flux (hysterisis loss) and excessive current draw from insulation breakdown on the aramture winding-- both contribute to overheating. Some excellent background on electric motor theory here, if you're interested.
Last edited on Wed Apr 6th, 2005 09:45 pm by Samurai Appliance Repair Man