Abstract: A motor control system for use in a high speed teleprinter or the like for controlling the rotational position and movement of a rotor, and apparatus driven by the rotor, by detecting back EMF induced into an unenergized field winding by rotational movement of the rotor. The output and input terminals of a first amplifier responsive to a first motor control signal, and a second amplifier responsive to a second motor control signal, are reactively coupled such that the amplifiers respond to either motor control signal to develop a signal simulating the signal into an unenergized winding of the motor due to mutual inductance with an energized winding. A differential voltage comparator provides a feedback signal indicative of motor performance upon comparing the simulated signal with the signal actually induced.