DETECTION AND ISOLATION CIRCUIT FOR A FAILED BRIDGE POWER RECTIFIER AND AN ELECTRICAL SYSTEM EMPLOYING SAME

摘要

A protection circuit for a bridge rectifier (116) having a plurality of ac inputs (124A-C) coupled to a plurality of line voltages, and a dc output, comprises monitoring circuits (142) coupled to the line voltages for monitoring the line voltages and generating sequential line-to-line voltage signals (144-148), conduction circuits (150) coupled to the monitoring circuits for conducting that portion of each of the sequential line-to-line voltage signals having a given polarity, the conduction circuits (150) generating sequential half wave voltage signals having a given polarity magnitude, and discriminating circuits (158) coupled to the conduction circuits for discriminating a faulted rectifier by monitoring the given polarity magnitude of each of the sequential half wave voltage signals. The discriminating circuits (158) generate a protection signal (160) in response to one of the magnitudes of the sequential half wave voltage signals being less than a threshold.