Electronic apparatus for testing the contact resistance of electromagnetic relays

Claim 1

A TEST SET FOR ELECTRO-MAGNETIC RELAYS COMPRISING A CIRCUIT UNIT FOR RECEIVING N TEST RELAYS EACH HAVING AN ENERGIZING COIL AND CONTACTS MOVABLE BETWEEN TWO POSITIONS, SAID CIRCUIT UNIT INCLUDING ELECTRICAL CONNECTIONS CONNECTING ALL THE COILS OF SAID RELAYS IN PARALLEL WITH EACH OTHER AND ALL THE CONTACTS OF SAID RELAYS IN SERIES WITH EACH OTHER WHEN SAID CONTACTS ALL LIE IN ONE OF SAID POSITIONS AND WHEN SAID CONTACTS ALL LIE IN THE OTHER OF SAID POSITONS, A FIRST SWITCH HAVING N+2 MOVABLE CONTACTS, ONE OF SAID CONTACTS BEING CONNECTED IN COMMON WITH ALL THE SAID COILS AND MOVABLE BETWEEN FIRST AND SECOND POSITIONS, AND N+1 OF SAID CONTACTS BEING MOVABLE BETWEEN THE TWO POSITIONS OF SAID TEST RELAY CONTACTS, EACH ONE OF SAID RELAY CONTACTS BEING CONNECTED BETWEEN TWO OF SAID SWITCH CONTACTS, A SOURCE OF ELECTRICAL SUPPLY FOR PRODUCING A FIRST, A SECOND AND A THIRD VOLTAGE, N INDICATOR ELEMENTS CONNECTED TO, AND OPERATED BY, SAID SOURCE OF SUPPLY, AN ELECTRICAL MOTOR CONNECTED TO SAID FIRST VOLTAGE SUPPLY SOURCE, A SECOND SWITCH CONNECTED TO SAID FIRST VOLTAGE SOURCE HAVING TWO MOVABLE CONTACTS SIMULTANEOUSLY OPERATED BY THE MOTOR, ONE OF SAID CONTACTS BEING ALTERNATELY MOVABLE BETWEEN THE FIRST AND SECOND POSITIONS OF SAID ONE CONTACT OF THE FIRST SWITCH TO ENERGIZE AND DE-ENERGIZE, ALTERNATELY, THE COILS OF ALL THE TEST RELAYS CONNECTED THERETO, AND N RELAY CONTACTS HAVING MOVABLE BETWEEN SAID TWO POSITIONS THEREOF IN RESPONSE TO SAID ENERGIZATION AND DE-ENERGIZATION, A DELAY CIRCUIT FOR PRODUCING A CONTROLLED CURRENT OUTPUT AND HAVING AN INPUT CIRCUIT AND AN OUTPUT CIRCUIT, SAID INPUT CIRCUIT BEING CONNECTED TO THE OTHER OF THE TWO MOVABLE CONTACTS OF THE SECOND SWITCH, THE SAID OTHER CONTACT ALTERNATELY CONNECTING THE FIRST VOLTAGE SOURCE, AND THE SECOND VALUE OF VOLTAGE SOURCE TO SAID INPUT CIRCUIT, THE CONTROLLED CURRENT OUTPUT BEING PRODUCED BY SAID DELAY CIRCUIT A PRE-DETERMINED PERIOD AFTER THE CONNECTION OF THE FIRST VOLTAGE SOURCE TO SAID INPUT AND MAINTAINED UNTIL THE SECOND VOLTAGE SOURCE IS CONNECTED TO SAID INPUT, N TRANSISTORS CONNECTED IN CASCADE, EACH OF SAID TRANSISTORS HAVING ONE ELECTRODE CONNECTED TO SAID FIRST VOLTAGE SOURCE, AN INPUT ELECTRODE AND AN OUTPUT ELECTRODE, THE OUTPUT OF SAID DELAY CIRCUIT BEING CONNECTED TO THE INPUT ELECTRODE OF AN INITIAL ONE OF SAID CASCADE CONNECTED TRANSISTORS, THE SAID CONTACTS OF THE N TEST RELAYS BEING RESPECTIVELY CONNECTED BETWEEN THE INPUT AND OUTPUT ELECTRODES OF SAID N TRANSISTORS, AND TO THE OUTPUT OF SAID DELAY CIRCUIT, IN ONE POSITION OF SAID FIRST SWITCH, N ELECTRO-MAGNETIC CONTROL RELAYS EACH HAVING AN ENERGIZING COIL AND FOUR CONTACTS, THE COILS OF SAID N CONTROL RELAYS BEING RESPECTIVELY CONNECTED BETWEEN THE SAID ONE ELECTRODES OF THE N TRANSISTORS AND THE SAID FIRST VALUE OF VOLTAGE, A FIRST ONE OF SAID CONTROL RELAY CONTACTS BEING CONNECTED ACROSS THE RELAY CONTACTS OF AN ASSOCIATED ONE OF SAID N TEST RELAYS AND MOVABLE BETWEEN FIRST AND SECOND POSITIONS TO PRODUCE AN OPEN CIRCUIT AND A SHORT CIRCUIT, RESPECTIVELY, ACROSS THE CONTACTS OF SAID ASSOCIATED TEST RELAYS, A SECOND ONE OF SAID CONTROL RELAY CONTACTS BEING CONNECTED BETWEEN THE COIL OF ITS ASSOCIATED CONTROL RELAY AND THE THIRD VOLTAGE SOURCE, AND MOVABLE BETWEEN FIRST AND SECOND POSITIONS TO DISCONNECT AND CONNECT, RESPECTIVELY, SAID THIRD VOLTAGE SOURCE TO SAID COIL, A THIRD ONE OF SAID CONTROL RELAY CONTACTS BEING CONNECTED BETWEENM SAID MOTOR AND SAID FIRST VOLTAGE SOURCE AND MOVABLE BETWEEN FIRST AND SECOND POSITIONS TO CONNECT AND DISCONNECT, RESPECTIVELY, SAID FIRST VOLTAGE SOURCE TO SAID MOTOR, A FOURTH ONE OF SAID CONTROL RELAY CONTACTS BEING CONNECTED BETWEEN SAID SOURCE OF SUPPLY AND AN ASSOCIATED ONE OF SAID N INDICATOR ELEMENTS AND MOVABLE BETWEEN FIRST AND SECOND POSITIONS TO DISCONNECT AND CONNECT, RESPECTIVELY, SAID INDICATOR ELEMENT TO SAID SOURCE OF SUPPLY, ANYONE OF SAID CONTROL RELAY COILS BEING ENERGIZED IN RESPONSE TO THE TEST RELAY CONTACTS CONNECTED IN SAID ONE POSITION OF SAID FIRST SWITCH EXHIBITING A RESISTANCE IN EXCESS OF A PRE-DETERMINED VALUE TO THE PASSAGE THERETHROUGH OF SAID CONTROLLED CURRENT, FOUR CONTACTS OF THE SAID CONTROL RELAY BEING MOVABLE FROM SAID FIRST TO SAID SECOND POSITION IN RESPONSE TO SAID ENERGIZATION AND THE CONTROL RELAY COIL BEING HELD ENERGIZED IN RESPONSE TO THE MOVEMENT OF ITS SECOND CONTACT FROM SAID FIRST TO SAID SECOND POSITION.