Abstract: A control device for a synchronous motor including a field winding discharge circuit having an alternating current when the synchronous motor has any slip and a field winding D.C. excitation circuit. The control device includes a digital counter for creating an output signal when the counter has counted a selected number of pulses during a given counting interval. The control circuit includes a means for creating counting pulses having a set frequency, means for directing the counting pulses to the counter, means responsive to the slip induced current in the discharge circuit for periodically resetting the counter and means responsive to the creation of an output signal between resetting operations for activating the excitation circuit. In this manner, if there is slip the synchronous motor operates in an induction mode until the slip is at a selected low level determined by the counter setting and the frequency of the pulses to the counter. During low slip conditions, the D.C.