Abstract: An alternating current speed control of the type associated with an alternating current motor whose output speed is essentially constant, the motor speed control being capable of varying the output speed of the motor from two times normal output to zero. The rotor of the electric motor is mounted on a cylindrical gear case which is in turn supported by the output shaft of a differential gearing mechanism disposed within the gear case. Controller means are provided to brake a regulating gear within the differential gear assembly to vary the output speed of the electric motor.