Low rise time surge testing apparatus

Claim 1

SURGE APPARATUS FOR TESTING ELECTRICAL EQUIPMENT WINDINGS AND THE LIKE AND COMPRISING: A TRANSFORMER (T3) HAVING ONE PRIMARY WINDING AND TWO SECONDARY WINDINGS, FIRST MEANS FOR APPLYING A VOLTAGE OF ONE POLARITY TO A TEST WINDING (17), SAID MEANS HAVING A LOAD CIRCUIT AND A CONTROL CIRCUIT, SAID LOAD CIRCUIT INCLUDING SAID TEST WINDING (17), A CHARGED CAPACITOR (C5), AND THE LOAD CIRCUIT ELEMENTS OF A THYRATRON (V4), WHILE SAID CONTROL CIRCUIT INCLUDES ONE OF SAID TRANSFORMER (T3) SECONDARY WINDINGS AND THE CONTROL CIRCUIT ELEMENTS OF SAID THYRATRON (V4), SAID LOAD CIRCUIT BEING WITHOUT LUMPED SERIES RESISTANCE, SECOND MEANS FOR SIMULTANEOULY APPLYING A VOLTAGE OF OPPOSITE POLARITY TO A REFERENCE WINDING (18), SAID MEANS HAVING A LOAD CIRCUIT AND A CONTROL CIRCUIT, SAID LOAD CIRCUIT INCLUDING SAID REFERENCE WINDING (18), A CHARGED CAPACITOR (C6), AND THE LOAD CIRCUIT ELEMENTS OF A THYRATRON (V3), WHILE SAID CONTROL CIRCUIT INCLUDES THE OTHER OF SAID TRANSFORMER (T3) SECONDARY WINDINGS AND THE CONTROL CIRCUIT ELEMENTS OF SAID LAST MENTIONED THYRATRON (V3), SAID LAST MENTIONED LOAD CIRCUIT BEING WITHOUT LUMPED SERIES RESISTANCE, AND MEANS FOR SENSING AND INDICATING THE DIFFERENCE OF INSTANTANEOUS VOLTAGE DROPS IN THE TWO WINDINGS DUE TO VOLTAGE AS THUS APPLIED, SAID LAST MEANS INCLUDING A BRIDGE CONNECTION (FIG. 4) OF THE TWO LOAD CIRCUITS AND AT LEAST ONE INDICATOR (30 OF FIG. 4, M2 OF FIG. 3, OR PREDETERMINED AMPLIFYING MEANS AND A LAMP OF FIG. 2) CONNECTED RESPONSIVE TO UNBALANCES IN THE BRIDGE.