Abstract: A contactor having a separable conduction path, an actuator, a magnetic stator and armature, and a controller, is disclosed. The actuator is in mechanical communication with the separable conduction path, and the magnetic stator and magnetic armature are arranged in field communication with each other and with an excitation coil responsive to a coil current that serves to generate a magnetic field directed to traverse the stator and the armature. The controller has a processing circuit adapted to control the coil current in response to the current and voltage at the coil such that the coil current is controlled in response to the position and closing speed of the separable conduction path prior to the separable conduction path closing during an open-to-close action.

Abstract: An earth fault detection circuit employs a differential current transformer and burden resistor to sample circuit current for potential earth fault current. A second order low pass filter circuit is employed to filter out harmonics within the protected circuit and a time delay circuit is used to insure the occurrence of a true earth fault leakage condition. A circuit with an operational amplifier is used to create a symmetric power supply for the rest of the circuits from a full wave rectified AC source.