Well... The world of AC motors gets a little complicated. Brushless DC motors are really permanent magnet AC motors that can't be plugged into the wall. They require that the controller control the polarity and timing of the power to the motor. (Several teams are using such motors currently, myself included) Brushed AC motors as are used in household appliances or industrial equipment are not widely used (or at all, as far as I know) and are generally meant for steady speed applications. Another possibility would be an AC induction motor which is also brushless but doesn't use permanent magnets. They are also generally meant for steady speed applications. I am not aware of anyone currently using one, but it would be interesting to see. So anyway.... What motor are you looking at?