PHASE IMBALANCE DETECTION CIRCUIT

摘要

A phase imbalance logic module for a solid state motor protection system for a three-phase motor. Three-phase line currents are converted to corresponding voltages and rectified. The resultant output voltage is a poorly regulated DC voltage having a ripple of approximately 4% during normal operating conditions. In the event of a phase failure, even if not total, the corresponding ripple percentage increases. The phase imbalance logic network senses ripple and provides an output signal to trip a protective circuit breaker if the component of ripple becomes significantly large.