An apparatus for controlling the speed of an AC motor comprising a switch adapted to be coupled in parallel with power terminals for the AC motor; a capacitor coupled in series with the parallel combination of the switch and the motor; the capacitor adapted to provide an AC supply voltage from an AC...http://www.google.ca/patents/US7330004?utm_source=gb-gplus-sharePatent US7330004 - Method and apparatus for quiet variable motor speed control
