Patent ID: 6191589
Filing Date: 2001-02-20
Classification: G01R,H02H

Abstract:
A test circuit for testing a circuit breaker, comprising:a circuit breaker, including:at least first and second conductors for carrying load current between a source and a load, and having at least one series breaking element for interrupting the flow of said load current,at least a first current sensor having an output coupled to said circuit breaker, wherein said at least first and second conductors are coupled to said current sensor for sensing the net current of said load current carried on said at least first and second conductors,wherein said current sensor further includes a shunt connected at each end to said first conductor for bypassing a small portion of said load current around said current sensor to unbalance the net flux producing an output of said current sensor, thereby increasing the detection sensitivity of said current sensor to a test current coupled in series with one of said first and second conductors, anda control circuit for detecting said test current, and providing an indication responsive to said test current; anda waveform generator circuit connected to said one of said first and second conductors for injecting a waveform including said test current into one of said conductors during a test operation wherein the other of said first and second mains conductors is open circuited.