shorts and grounds with a ohm meter. The only other test that would be done is with a "megger" but that most likely wouldn't be needed. Take one lead and put it to one of the motor wires. Take the other lead and put it to the other motor wire. Put the meter on ohms x 1 and see if you get continuity (the buzzer beeps and the meter swings). It would be good if it did because that means the winding would be intact. Then take one of the leads and put it to one of the wires on the motor and the other to the case of the motor. Hopefully the buzzer will not buzz and the meter will not swing. If it does then the motor has a ground. If the winding is intact and not grounded then your problem is most likely the bearings in wench itself. These test will show up 90% of the problems.