Abstract: A ground-fault circuit-interrupter (GFCI) system is provided that provides reliable and timely tripping of faulted circuits while minimizing so-called “nuisance” tripping. The GFCI includes a voltage unbalance detection device coupled to the main bus circuit for detecting a voltage unbalance during a fault condition. A computer processor in communication with the voltage unbalance detection device is programmed to determine when an actual fault condition exists based on a state of the voltage unbalance and certain predetermined among the fault signal generated by a GFCI unit in the main bus circuit and the fault signals generated by GFCI units in individual feeder circuits.

Abstract: In an electric or hybrid electric vehicle, a voltage monitor (102) is directly coupled to a traction motor (38) and/or generator motor (30) to detect a permanent magnet induced voltage within the motor at a predetermined speed and no load condition. A controller (100) compares the detected permanent magnet induced voltage with an expected reference voltage that represents an expected permanent magnet induced voltage at full magnetization and the predetermined speed. The comparison includes identifying points of synchronization and using those points to determine a difference in the detected permanent magnet induced voltage that is caused by a faulty component.