Abstract: A motor speed control system which comprises: (a) a power modulator circuit having gating means adapted to control the power supplied to the motor; (b) means adapted to provide a voltage which is directly proportional to the instantaneous motor terminal current; (c) means adapted to provide a sensing current which is directly proportional to the voltage across means (b), and thus to the instantaneous motor terminal current; (d) means adapted to provide a sensing current which is directly proportional to the instantaneous motor terminal voltage; (e) summing means adapted to algebraically sum the instantaneous values of the two sensing currents; (f) integrator means adapted to average the sum of instantaneous values provided by means (e); and, (g) feedback means adapted to generate a signal for operating the gating means, said signal having a phase determined by the output of the integrator means, whereby the output of the integrator means controls the phase of the gating means and thereby controls the power su