Full wave d. c. motor speed and position control system

Claim 1

IN AN APPARATUS FOR CONTROLLING CURRENT FLOW TO A REVERSIBLE DIRECT CURRENT MOTOR IN RESPONSE TO A SIGNAL FROM A SIGNAL SOURCE, THE COMBINATION COMPRISING; A SOURCE PROVIDING ALTERNATE HALF CYCLES OF OPPOSITE POLARITY CURRENT, A TRANSFORMER SECONDARY WINDING HAVIG A PAIR OF OUTPUT TERMINALS AND A TAP CENTERED BETWEEN THE OUTPUT TERMINALS, SAID MOTOR HAVING AN ARMATURE WINDING CONNECTED TO A PAIR OF MOTOR INPUT TERMINALS WITH ONE OF SAID MOTOR INPUT TERMINALS CONNECTED TO SAID CENTER TAP, A FIRST PAIR OF OPPOSITELY POLED UNIDIRECTIONAL CONDUCTING DEVICES CONNECTED BETWEEN ONE OF THE OUTPUT TERMINALS OF THE TRANSFORMER SECONDARY WINDING AND THE OTHER OF SAID MOTOR INPUT TERMINALS, A SECOND PAIR OF OPPOSITELY POLED UNIDIRECTIONAL CONDUCTING DEVICES CONNECTED BETWEEN THE OTHER OF THE OUTPUT TERMINALS OF THE TRANSFORMER SECONDARY WINDING AND THE SAID OTHER MOTOR INPUT TERMINAL, EACH OF SAID DEVICES HAVING A CONTROL ELECTRODE ARRANGED FOR INITIATING CONDUCTION OF THE DEVICE ASSOCIATED THEREWITH DURING THE HALF CYCLES WHEN THE CURRENT POLARITY OF THE SOURCE IS COMPLEMENTARY WITH THE CONDUCTING DIRECTION OF THE DEVICE, AN INDIVIDUAL FIRING MEANS CONNECTED TO THE CONTROL ELECTRODE OF EACH OF SAID DEVICES, SAID FIRING MEANS BEING CONNECTED IN CIRCUIT WITH THE SIGNAL SOURCE TO RECEIVE AN INPUT FROM THE SIGNAL SOURCE AND IN RESPONSE TO SAID INPUT SIGNAL PROVIDE AN OUTPUT SIGNAL TO THE CONTROL ELECTRODES OF SAID DEVICES AT A PREDETERMINED INSTANT DURING THE HALF CYCLE OF SAID SOURCE, A BIAS MEANS CONNECTED IN THE CIRCUIT BETWEEN THE SIGNAL SOURCE AND FIRING MEANS, SAID BIAS MEANS BEING ARRANGED TO CAUSE BOTH OF THE DEVICES OF A SELECTED PAIR OF THE DEVICES TO INITIATE CONDUCTION AT A LATE INSTANT IN THE RESPECTIVE HALF CYCLES OF CONDUCTION OF THE RESPECTIVE DEVICES FOR SUPPLYING THE MOTOR ARMATURE WITH EQUAL MAGNITUDE PULSES OF ALTERNATING OPPOSITE POLARITY CURRENT DURING INTERVALS OF A ZERO SIGNAL FROM THE SIGNAL SOURCE, SAID FIRING MEANS BEING ARRANGED TO PROGRESSIVELY INCREASE THE CONDUCTION INTERVAL DURING EACH HALF CYCLE OF CONDUCTION OF ONE OF THE DEVICES IN EACH PAIR WHILE SIMULTANEOUSLY DESCREASING THE CONDUCTION INTERVAL DURING EACH HALF CYCLE OF CONDUCTION OF THE OTHER OF SAID BOTH DEVICES OF THE SELECTED PAIR OF RESPONSE TO THE POLARITY AND MAGNITUDE OF THE SIGNAL FROM THE SIGNAL SOURCE WHEREBY THE CURRENT FLOW IN THE MOTOR ARMATURE PROGRESSIVELY CHANGES FROM ALTERNATING EQUAL MAGNITUDE OPPOSITE POLARITY CURRENT PULSES OF SMALL MAGNITUDE OF FULL WAVE RECTIFIED DIRECT CURRENT PULSES HAVING A POLARITY ANY MAGNITUDE DEPENDENT UPON THE POLARITY AND MAGNITUDE OF THE SIGNAL FROM THE SIGNAL SOURCE.