Abstract: A workpiece clamp actuator system which includes a clamping mechanism and an induction motor having an output coupled to the clamping mechanism for moving the mechanism between an unclamped position in abutment with a stop and a clamped position in abutment with a workpiece. A motor controller selectively feeds energy from first and second power supplies to the induction motor, the first power supply having an output voltage and frequency selected to obtain rapid initial motion at the clamp, and the second power supply having an output frequency equal to the slip frequency of the motor at rated torque and an output voltage selected to provide full load current, and thus maximum torque, at both the clamped and unclamped positions.