VI; The principle applies to AC or DC. With the heater motor, the resistance doesn't change, so the current is going to be directly proportionate to the voltage.

With the the dual voltage electric motor, you can't just plug into either voltage without changing some wiring around, usually a jumper/strap with some numbered terminals (at least on the ones I've seen). So, using the formula that squeeze supplied above, we see that the resistance of the motor at 240V is 12 ohms, and the resistance at 120V is 3 ohms. hence the difference in current. The wattage of the motor however (Voltage times Current) is the same at either voltage.

Last edited by waldo53; 08/17/2010 10:03 PM.