Abstract: Apparatus for synchronizing the relative positions of motor-driven machines. Preliminary to operating the machines in synchronism, the rotors of individual synchronous motors that drive the machines are moved to a stop at certain angular positions. The angular positions are such that when inverter voltage is thereafter applied to the stators of all of the motors from a common inverter, the instantaneous angular position of the stator magnetic field with respect to the respective rotor is the same for all of the motors. In one embodiment, several machines are synchronized as to position by first operating each at low speed to a home position.