Electronic alarm or tripping system

Claim 1

AN ARRANGEMENT FOR THE DETECTION OF LEAKAGE CURRENTS IN ELECTRICAL APPARATUS COMPRISING, IN COMBINATION, AN ELECTRICAL POWER SOURCE SUPPLPYING ELECTRICAL CURRENT TO SAID APPARATUS THROUGH AT LEAST TWO SUPPLY LINES CARRYING IDENTICAL CURRENTS DURING NORMAL OPERATING CONDITIONS, AND CARRYING UNEQUAL CURRENTS UNDER ABNORMAL OPERATING CONDITIONS WHEN SAID LEAKAGE CURRENTS PREVAIL IN SAID APPARATUS; A MAGNETIC CORE; A FIRST PRIMARY WINDING WOUND UPON SAID MAGNETIC CORE AND CONNECTED BETWEEN SAID APPARATUS AND ONE SUPPLY LINE OF SAID ELECTRICAL POWER SOURCE; A SECOND PRIMARY WINDING WOUND UPON SAID MAGNETIC CORE AND CONNECTED BETWEEN SAID APPARATUS AND THE OTHER SUPPLY LINE OF SAID ELECTRICAL POWER SOURCE, SAID SECOND PRIMARY WINDING BEING WOUND UPON SAID CORE OPPOSITELY TO THAT OF SAID FIRST PRIMARY WINDING SO THAT THE MAGNETIC FLUX GENERATED THROUGH SAID CORE AS A RESULT OF SAID PRIMARY WINDINGS IS NULL DURING NORMAL OPERATING CONDITIONS; A FIRST SECONDARY WINDING WOUND UPON SAID COPRE AND HAVING AN INDUCED CURRENT WHEN SAID MAGNETIC FLUX IN SAID CORE IS DIFFERENT FROM NULL UNDER SAID ABNORMAL OPERATING CONDITIONS; A TRANSISTOR CONNECTED TO SAID FIRST SECONDARY WINDING AND MADE CONDUCTIVE WHEN SAID INDUCED CURRENT EXCEEDS A PREDETERMINED VALUE; A SECOND SECONDARY WINDING WOUND UPON SAID CORE AND ENERGIZED BY SAID TRANSISTOR WHEN LATTER IS MADE CONDUCTIVE; AND INDICATING MEANS CONNECTED TO SAID SECOND SECONDARY WINDING AND ACUTATED BY THE CURRENT FLOWING THERETHROUGH TO INDICATE THE EXISTENCE OF ABNORMAL OPERATING CONDITIONS.