A.c. control systems for providing variable half-cycle power pulses

Claim 1

A CONTROL SYSTEM THAT CAN BE CONNECTED TO AN A.C. SUPPLY AND TO A LOAD TO PROVIDE POWER PULSES FOR SAID LOAD AND THAT COMPRISES: (A) A CONTROLLED RECTIFIER THAT CAN BE RENDERED CONDUCTIVE TO START SUPPLYING A POWER PULSE TO SAID LOAD, (B) A SECOND CONTROLLED RECTIFIER THAT CAN BE RENDERED CONDUCTIVE TO START SUPPLYING A SECOND POWER PULSE TO SAID LOAD, (C) A CAPACITOR, (D) SAID CAPACITOR BEING ADAPTED TO SELECTIVELY CAUSE INVERSE CURRENT TO FLOW THROUGH THE FIRST SAID CONTROLLED RECTIFIER AND THEREBY RENDER SAID FIRST SAID CONTROLLED RECTIFIER NON-CONDUCTIVE AND TO SELECTIVELY CAUSE INVERSE CURRENT TO FLOW THROUGH SAID SECOND CONTROLLED RECTICIER AND THEREBY RENDER SAID SECOND CONTROLLED RECTIFIER NON-CONDUCTIVE, (E) THE FIRST SAID CONTROLLED RECTIFIER BEING RENDERED CONDUCTIVE TO START SUPPLYING THE FIRST SAID POWER PULSE TO SAID LOAD AT THE START OF POSITIVE-GOING HALFCYCLES OF SAID A.C. SUPPLY, (F) SAID SECOND CONTROLLED RECTIFIER BECOMING CONDUCTIVE DURING SAID POSITIVE-GOING HALF-CYCLES OF SAID A.C. SUPPLY TO ENABLE SAID CAPICATOR TO CAUSE INVERSE CURRENT TO FLOW THROUGH SAID FIRST SAID CONTROLLED RECTIFIER AND THEREBY RENDER SAID FIRST SAID CONTROLLED RECTIFIER NON-CONDUCTIVE AND TO THEREAFTER ENABLE SAID CAPACITOR TO DISCHARGE AND THEN CHARGE IN THE OPPOSITE DIRECTION, (G) SAID SECOND CONTROLLED RECTIFIER BEING RENDERED CONDUCTIVE TO START SUPPLYING SAID SECOND POWER PULSE TO SAID LOAD AT THE START OF NEGATIVE-GOING HALF-CYCLES OF SAID A.C. SUPPLY (H) THE FIRST SAID CONTROLLED RECTIFIER BECOMING CONDUCTIVE DURING SAID NEGATIVE-GOING HALF-CYCLES OF SAID A.C. SUPPLY TO ENABLE SAID CAPACITOR TO CAUSE INVERSE CURRENT TO FLOW THROUGH SAID SECOND CONTROLLED RECTIFIER AND THEREBY RENDER SAID SECOND CONTROLLED RECTIFIER NON-CONDUCTIVE AND TO THEREAFTER ENABLE SAID CAPACITOR TO DISCHARGE AND THEN CHARGE IN ITS INITIAL DIRECTION, (I) A SIGNAL SOURCE THAN CAN SUPPLY "TURN ON" SIGNALS TO THE FIRST SAID CONTROLLED RECTIFIER DURING POSITIVEGOING HALF-CYCLES OF SAID A.C. SUPPLY TO ENABLE SAID FIRST SAID CONTROLLED RECTIFIER TO SERVE AS A POWERSUPPLYING CONTROLLED RECTIFIER AND THAT CAN SUPPLY "TURN ON" SINGALS TO SAID SECOND CONTROLLED RECTIFIER DURING NEGATIVE-GOING HALF-CYCLES OF SAID A.C. SUPPLY TO ENABLE SAID SECOND CONTROLLED RECTIFIER TO SERVE AS A POWER-SUPPLYING CONTROLLED RECTIFIER, (J) A SECOND SIGNAL SOURCE THAT CAN SUPPLY COMMUTATIN SIGNALS TO SAID SECOND CONTROLLED RECTIFIER DURING SAID POSITIVE-GOING HALF-CYCLES OF SAID A.C. SUPPLY TO CAUSE SAID SECOND CONTROLLED RECTIFIER TO SERVE AS A COMMUTATING CONTROLLED RECTIFIER AS BY RENDERING SAID SECOND CONTROLLED RECTIFIER CONDUCTIVE AND THEREBY ENABLING SAID CAPACITOR TO PASS INVERSE CURRENT THROUGH SAID FIRST SAID CONTROLLED RECTIFIER TO RENDER SAID FIRST SAID CONTROLLED RECTIFIER NON-CONDUCTIVE AND THAT CAN SUPPLY COMMUTATING SIGNALS TO SAID FIRST SAID CONTROLLED RECTIFIER DURING SAID NEGATIVE-GOING HALF-CYCLES OF SAID A.C. SUPPLY TO CAUSE SAID FIRST SAID CONTROLLED RECTIFIER TO SERVE AS A COMMUTATING CONTROLLED RECTIFIER AS BY RENDERING SAID FIRST SAID CONTROLLED RECTIFIER CONDUCTIVE AND THEREBY ENABLING SAI CAPACITOR TO PASS INVERSE CURRENT THROUGH SAID SECOND CONTROLLED RECTIFIER TO RENDER SAID SECOND CONTROLLED RECTIFIER NON-CONDUCTIVE, (K) THE FIRST SAID SIGNAL SOURCE SUPPLYING SAID "TURN ON" SIGNALS CLOSE TO THE BEGINNINGS OF SAID HALF-CYCLES OF SAID A.C. SUPPLY, (I) SAID SECOND SIGNAL SOURCE RENDERING SAID COMMUTATING CONTROLLED RECTIFIERS CONDUCTIVE BEFORE THE ENDS OF SAID HALF-CYCLES OF SAID A.C. SUPPLY, (M) SAID SECOND SIGNAL SOURCE BEING ADAPTED TO VARY THE TIME INTERVAL BETWEEN SAID "TURN ON" SIGNALS AND THE RENDERING OF SAID COMMUTATING CONTROLLED RECTIFIERS CONDUCTIVE.