Apparatus for supplying fullwave rectified current from an a.c. source to a load

Claim 1

APPARATUS FOR CONTROLLING THE SUPPLY OF ELECTRIC CURRENT TO A LOAD, COMPRISING IN COMBINATION FIRST AND SECOND BRIDGE RECTIFIER CIRCUITS, EACH HAVING A PAIR OF DIAGONALLY OPPOSITE JUNCTIONS TO THE ARMS THEREOF FOR CONNECTION BETWEEN THE LOAD AND A SOURCE OF ALTERNATING CURRENT POWER AND BEING ARRANGED NORMALLY TO PREVENT THE FLOW OF CURRENT FROM THE SAID SOURCE OF ALTERNATING CURRENT POWER TO THE LOAD, MEANS FOR SUPPLYING AN ALTERNATING REFERENCE VOLTAGE CONNECTED IN SERIES WITH A CONTROLLABLE RECTIFIER ACROSS THE OTHER TWO JUNCTIONS OF THE OTHER ARMS OF EACH BRIDGE CIRCUIT, SAID REFERENCE VOLTAGE BEING IN PHASE WITH THE VOLTAGE SUPPLIED FROM SAID SOURCE, SO AS TO RENDER EACH BRIDGE CIRCUIT IN TURN CAPABLE OF CONDUCTION BETWEEN SAID SOURCE AND THE LOAD WHEREBY TO ENERGIZE THE LOAD WITH FULL WAVE RECTIFIED CURRENT FROM SAID SOURCE, MEANS COMPRISING A POWER SELSYN INTERPOSED BETWEEN SAID SOURCE AND SAID FIRST AND SECOND BRIDGE CIRCUITS FOR CHANGING THE PHASE OF THE VOLTAGE SUPPLIED TO SAID BRIDGE CIRCUITS WHEREBY TO CHANGE THE POLARITY OF THE CURRENT SUPPLIED TO THE LOAD, AND MEANS FOR RENDERING EACH SAID CONTROLLABLE RECTIFIER CONDUCTIVE AT A FREQUENCY DETERMINED BY THE FREQUENCY OF THE REFERENCE VOLTAGE WHEREBY A CURRENT IS CAUSED TO FLOW FROM SAID MEANS FOR SUPPLYING SAID REFERENCE VOLTAGE THROUGH EACH BRIDGE CIRCUIT IN TURN TO BIAS THE BRIDGE CIRCUITS SO THAT THEY ALLOW CURRENT TO FLOW FROM SAID SOURCE TO THE LOAD.