Protective circuit arrangement

Claim 1

A PROTECTIVE CIRCUIT ARRANGEMENT FOR ELECTRICAL EQUIPMENT ADAPTED TO BE CONNECTED TO A POWER SUPPLY SOURCE COMRISING: FAULT CIRCUIT MEANS INCLUDING A DIFFERENTIAL TRANSFORMER COUPLED TO SAID ELECTRICAL EQUIPMENT FOR SENSING ELECTRICAL GROUND CURRENTS PRODUCED BY GROUND FAULTS IN THE EQUIPMENT, SAID FAULT CIRCUIT MEANS BEING RESPONSIVE TO GROUND CURRENTS IN SAID EQUIPMENT TO PRODUCE FIRST SIGNAL OUTPUT; OVERLOAD CIRCUIT MEANS INCLUDING A CURRENT TRANSFORMER HAVING A PRIMARY WINDING COUPLED TO THE ELECTRICAL EQUIPMENT AND THERMAL CURRENT MEANS COUPLED TO THE SECONDARY WINDING FOR DETECTING AT LEAST A PORTION OF THE CURRENT IN THE ELECTRICAL EQUIPMENT, SAID THERMAL CURRENT MEANS BEING LOCATED TO DETECT THE TEMPERATURE OF THE EQUIPMENT, SAID OVERLOAD CIRCUIT MEANS BEING RESPONSIVE TO PREDETERMINED COMBINATIONS OF CURRENT AND TEMPERATURE TO PRODUCE A SECOND SIGNAL OUTPUT, SUPPLY CIRCUIT CONTROL MEANS FOR CONNECTING THE EQUIPMENT TO SAID SOURCE AND COUPLED TO SAID FAULT AND OVERLOAD CIRCUIT MEANS, SAID CONTROL MEANS BEING RESPONSIVE TO A PREDETERMINED VALUE OF EITHER SIGNAL OUTPUT TO DISCONNECT THE ELECTRICAL EQUIPMENT FROM SAID SUPPLY SOURCE.