Leakage detection and control circuit

• US 3,296,493 A
• Filed: 11/05/1964
• Issued: 01/03/1967
• Est. Priority Date: 11/05/1964
• Status: Expired due to Term

• Current Assignee: Edward T. Thomson, Vernon Whittaker
• Original Assignee: Edward T. Thomson, Vernon Whittaker
• Inventors: Whittaker, Vernon, Thomson, Edward T.
• Application Number:
  US04/409,240
• Time in Patent Office: 789 Days
• US Class Current: 361/45
• CPC Class Codes: H02H 3/33 using summation current transformers H02H3/347 takes precedence

Claims

1. A PROTECTIVE CIRCUIT FOR A LOAD CIRCUIT COMPRISING:

(A) INDUCTIVE MEANS COMPRISING;

(I) A FIRST WINDING COUPLED BETWEEN A FIRST INPUT TERMINAL TO SAID PROTECTIVE CIRCUIT AND A FIRST OUTPUT TERMINAL THEREOF, (II) A SECOND WINDING COUPLED BETWEEN A SECOND INPUT TERMINAL TO SAID PROTECTIVE CIRCUIT AND A SECOND OUTPUT TERMINAL THEREOF, SAID LOAD CIRCUIT BEING ADAPTED TO BE CONNECTED BETWEEN SAID OUTPUT TERMINALS AND SAID INPUT TERMINALS BEING ARRANGED TO BE CONNECTED TO A VOLTAGE SOURCE, SAID FIRST AND SECOND WINDINGS BEING ARRANGED TO PRODUCE OPPOSITE MAGNETIC FIELDS TENDING SUBSTANTIALLY TO CANCEL ONE ANOTHER WHEN SAID LOAD CIRCUIT IS OPERATING UNDER NORMAL CONDITIONS, (III) A THIRD WINDING DISPOSED SO AS TO BE THREADED BY AT LEAST PART OF THE RESPECTIVE MAGNETIC FIELDS PRODUCED BY SAID FIRST AND SECOND WINDINGS, (B) FIRST SWITCHING MEANS COUPLED BETWEEN SAID INPUT TERMINALS, (C) SECOND SWITCHING MEANS BEING COUPLED TO SAID FIRST INPUT TERMINAL VIA SAID FIRST SWITCHING MEANS AND ALSO BEING COUPLED TO SAID SECOND INPUT TERMINAL, SAID SECOND SWITCHING MEANS INCLUDING MEANS FOR DECOUPLING SAID OUTPUT TERMINALS FROM SAID INPUT TERMINALS, AND (D) THIRD SWITCHING MEANS COUPLED BETWEEN SAID INPUT TERMINALS AND TO SAID THIRD WINDING, SAID THIRD SWITCHING MEANS BEING CLOSED WHEN SAID THIRD WINDING HAS NO VOLTAGE INDUCED THEREIN BY FIELDS PRODUCED BY SAID FIRST AND SECOND WINDINGS THEREBY BYPASSING SAID FIRST SWITCHING MEANS, SAID THIRD SWITCHING MEANS BEING CONSTRUCTED TO OPEN IN THE PRESENCE OF A PREDETERMINED AMOUNT OF VOLTAGE INDUCED IN SAID THIRD WINDING THEREBY ENABLING ACTUATION OF SAID FIRST SWITCHING MEANS BY SAID VOLTAGE SOURCE, SAID FIRST SWITCHING MEANS THEREUPON ACTUATING SAID SECOND SWITCHING MEANS SO AS TO DECOUPLE SAID LOAD CIRCUIT FROM SAID INPUT TERMINALS.