Tripping arrangement for an electric circuit breaker

Claim 1

AN OVERCURRENT-SENSITIVE TRIPPING ARRANGEMENT FOR AN ELECTRIC CIRCUIT BREAKER COMPRISING: (A) A NORMAL TRIP DEVICE OPERABLE TO CAUSE OPENING OF SAID CIRCUIT BREAKER, (B) A STAND-BY TRIP DEVICE OPERABLE TO CAUSE OPENING OF SAID CIRCUIT BREAKER, (C) THE STAND-BY TRIP DEVICE BEING CAPABLE OF OPERATING IN RESPONSE TO A SUBSTANTIALLY LOWER ENERGY INPUT THAN THE NORMAL TRIP DEVICE, (D) A TRIP CIRCUIT FOR SUPPLYING OPERATING ENERGY TO SAID NORMAL TRIP DEVICE IN RESPONSE TO OVERCURRENTS EXCEEDING A PREDETERMINED VALUE, SAID TRIP CIRCUIT COMPRISING A CONTROL POWER CIRCUIT HAVING TERMINALS ACROSS WHICH A CONTROL VOLTAGE HAVING A PREDETERMINED MINIMUM VALUE MUST BE PRESENT TO CAUSE SAID TRIP CIRCUIT OF EFFECT OPERATION OF SAID NORMAL TRIP DEVICE IN RESPONSE TO SAID OVERCURRENTS, (E) AND MONITORING MEANS SENSITIVE TO THE VOLTAGE ACROSS SAID TERMINALS FOR NORMALLY MAINTAINING SAID STAND-BY TRIP DEVICE INSENSITIVE TO SAID OVERCURRENT, SAID MONITORING MEANS BEING RESPONSIVE TO A DROP IN SAID CONTROL VOLTAGE TO A PREDETERMINED LEVEL TO RENDER SAID STAND-BY TRIPPING DEVICE RESPONSIVE TO SAID OVERCURRENTS, (F) SAID STAND-BY TRIPPING DEVICE INCLUDING MEANS EFFECTIVE WHEN SAID STAND-BY TRIP DEVICE HAS BEEN RENDERED RESPONSIVE TO OVERCURRENTS FOR PRECLUDING SAID STAND-BY TRIP DEVICE FROM OPERATING TO OPEN SAID CIRCUIT BREAKER UNTIL AN OVERCURRENT IS PRESENT, WHEREBY SAID CIRCUIT BREAKER CAN REMAIN CLOSED IF NO OVERCURRENT IS PRESENT WHEN SAID CONTROL VOLTAGE DROPS TO SAID PREDETERMINED LEVEL.