477205015UC1 Stearns SINPAC Electronic Switch2VR Series for 230 Vac Capacitor Start Capacitor Run Motors Basic Operation Capacitor start capacitor run motors and capacitor start motors provide continuous voltage sensing information which can be used to extract speed data from the voltage across the motor start (auxiliary) winding. By comparing this start (auxiliary) winding RPM sensitive voltage to the main AC input voltage (which serves as a reference voltage), the switch determines when the