Abstract: A controller for achieving quiet operation of an AC motor utilizes an arrement of force-commutated, controlled rectifiers that are gated in a manner that results in the motor windings being energized with a preselected number of adjustable width, current pulses during each half cycle of the power supply. In the interval between pulses the motor winding is short circuited so that the motor current remains continuous upon commutation between the "on" and "off" states. The number of pulses are selected so as to reduce those magnetic field stress harmonics that are responsible for the excitation of vibration and noise.