There should be a voltage range in the nameplate on the enclosure of the motor or in the manual.

Normally this voltage range is same for AC or DC.For example,24-240,you can applied 24dc or ac,240 dc or ac.Higher voltage applied,more power the motor can output.So you can apply 24dc...48dc...50dc...100dc......to the motor,it depends on your appliance!!
But DO NOT exceed the rated voltage range!!!!

There is a frequency requirement for ac supply,for example 60HZ!!

when applied same voltage to this kind of motor,dc is more effective than ac!!

[This message has been edited by peterpang (edited 01-22-2005).]