A voltage regulator for a pair of electric motors has an input for a signal indicative of the desired speed for the motors and a pulse width modulation control circuit device. A control module provides a conditioning signal to the control circuit to output to the motors a square wave voltage having a duty-cycle which varies according to a predetermined function of the signal applied to the input of the regulator. The control circuit device has first and second electronic solid state switches associated with the motor and controlled by the control module.