Cable fault locator for ungrounded electrical systems including means for applying a square wave to the cable under test

Claim 1

A GROUND FAULT LOCATOR DEVICE FOR USE ON AN UNDERGROUNDED ELECTRICAL SYSTEM INCLUDNG A SEVERAL CONDUCTOR WIRES COMPRISING: (A) A RELAY HAVING A COIL AND A TRIPLE POLE-SINGLE THROW SWITCH SAID TP-ST SWITCH HAVING FIRST, SECOND AND THIRD POLES AND FIRST, SECOND AND THIRD STATIONARY CONTACTS, SAID SECOND AND THIRD POLES BEING ELECTRICALLY CONNECTED, (B) A SOURCE OF A.C. CONNECTED ACROSS SAID FIRST AND SECOND OF SAID POLES OF SAID TP-ST SWITCH, (C) A SECOND RELAY HAVING A COIL AND A DOUBLE POLEDOUBLE THROW SWITCH, (D) A THERMAL RELAY FOR ALTERNATELY OPENING AND SHORTING CIRCULATING A LINE IN WHICH IT IS PLACED, (E) A FIRST SERIES CIRCUIT PATH HAVING INCLUDED THEREIN SAID THERMAL CONTACTOR, SAID FIRST AND SECOND STATIONARY CONTACTS OF SAID TP-ST SWITCH, SAID COIL OF SAID SECOND RELAY, (F) A NORMALLY OPEN START SWITCH, (G) A SECOND SERIES PATH HAVING INCLUDED THEREIN SAID FIRST POLE OF SAID TP-ST SWITCH, SAID COIL OF SAID TP-ST SWITCH, SAID THIRD STATIONARY CONTACT OF SAID TP-ST SWITCH, SAID START SWITCH, SAID THIRD POLE OF SAID TP-ST SWITCH, (H) RECTIFIER MEANS HAVING ITS INPUT CONNECTED ACROSS SAID FIRST AND SECOND STATIONARY CONTACTS AND ITS OUTPUT CONNECTED ACROSS PARALLELED STATIONARY CONTACTS OF SAID DP-DT SWITCH, (I) ONE OF THE POLES OF SAID DP-DT SWITCH BEING GROUNDED AND THE OTHER POLE PROVIDED WITH CONNECTION MEANS TO A WIRE OF SAID ELECTRICAL SYSTEM ALONG WHICH A GROUND IS TO BE LOCATED, (J) DETECTOR MEANS MOVABLE ALONG A WIRE FOR DETECTING THE CHANGING POLARITY CURRENT IN SAID WIRE WHEREBY A GROUND FAULT CAN BE LOCATED THEREIN.