The motor is serially connected with a diode and a sensing resistor so that half waves of one polarity, for example negative, can flow through the motor and provide, across the resistor, a voltage drop corresponding to loading placed on the motor. A thyristor is connected in parallel to the diode and reversely poled to conduct the other half wave, then the positive, if triggered. Triggering of the thyristor is controlled by the voltage drop across the sensing resistor so that, under no-load conditions, only the negative half waves will be applied to the motor, thus limiting its no-load speed but, as loading is placed thereon, increasing portions of the positive half waves are likewise passed through the motor. The diode may, itself, be a controlled diode such as a thyristor which is rendered conductive by a phase control network, thus providing speed control for the motor, controlling actually only the negative half wave but, due to sensing resistor, effectively, regulating the motor current during both half waves. The circuit uses a capacitor which is charged to the voltage forming the control voltage on the thyristor conducting the positive half wave.