Ground fault responsive protective system for electric power distribution apparatus

Claim 1

IN ELECTRIC POWER SWITCHGEAR: (A) A MULTICONDUCTOR POLYPHASE A.C. ELECTRIC POWER BUS; (B) SWITCHING MEANS FOR CONNECTING SAID BUS TO A SOURCE OF POLYPHASE A.-C. ELECTRIC ENERGY HAVING ONE TERMINAL ADAPTED FOR GROUNDING, THE SWITCHING MEANS BEING EQUIPPED WITH A NORMALLY DEENERGIZED TRIP COIL AND BEING OPENABLE TO DISCONNECT THE BUS FROM THE SOURCE UPON ENERGIZATION OF SAID TRIP COIL; (C) MAIN RELAYING MEANS CONNECTED TO SAID TRIP COIL AND ACTIVATED BY GROUND CURRENT FLOWING THROUGH SAID SWITCHING MEANS FOR EFFECTING ENERGIZATION OF SAID TRIP COIL; (D) A PLURALITY OF CIRCUIT CONTROLLING MEANS FOR CONNECTING A PLURALITY OF FEEDER CIRCUITS RESPECTIVELY TO SAID BUS; AND (E) A PLURALITY OF FEEDER RELAYING MEANS RESPECTIVELY CONNECTED TO SAID CIRCUIT CONTROLLING MEANS, ALL OF THE FEEDER RELAYING MEANS BEING CONNECTED IN COMMON TO SAID MAIN RELAYING MEANS AND EACH OF THEM BEING RESPONSIVE TO GROUND CURRENT FLOWING THROUGH SAID SWITCHING MEANS AND THROUGH THE ASSOCIATED CIRCUIT CONTROLLING MEANS FOR SUBSTANTIALLY INSTANTANEOUSLY PREVENTING ACTIVATION OF SAID MAIN RELAYING MEANS, THEREBY RENDERING IT INEFFECTIVE TO OPEN THE SWITCHING MEANS, AND FOR EFFECTING A CIRCUIT OPENING OPERATION OF THE ASSOCIATED CONTROLLING MEANS.