your speed control was designed to work on 120ac 60 cycle for a u.s.a. machine. if you connected it to a 220 or 50 cycle you can blow the electronic in the speed control the motor may be ok. if you connect the leads from motor to a dc power supply above 25 volts to no more than 70 it shound run if good not damaged many of the machines use a perminate magnet motor for variable speed and unless the windings are burned out it should run. the speed controls are sensitive to wrong voltages and moisture. mike zinski