Scr power supply for motor speed control system

Claim 1

A REGULATED POWER SUPPLY FOR A DIRECT CURRENT SHUNT MOTOR COMPRISING, IN COMBINATION: SEPARATE FULL-WAVE RECTIFIER MEANS ADAPTED TO BE COUPLED TO AN ALTERNATING VOLTAGE SOURCE AND TO THE FIELD WINDING OF THE SHUNT MOTOR FOR PROVIDING ENERGY THERETO DURING BOTH POSITIVE AND NEGATIVE HALF-CYCLES OF THE APPLIED ALTERNATING VOLTAGE WAVE; A SILICON-CONTROLLED RECTIFIER HAVING ANODE, CATHODE, AND GATE TERMINALS; A FILTER CIRCUIT INCLUDING AN INDUCTANCE COIL AND A CAPACITOR COUPLED TOGETHER IN SERIES; BILATERALLY CONDUCTIVE CIRCUIT MEANS COUPLING ONE END OF SAID FILTER CIRCUIT TO SAID CATHODE OF SAID SILICONCONTROLLED RECTIFIER; CIRCUIT MEANS ADAPTED FOR COUPLING THE OTHER END OF SAID FILTER CIRCUIT, AND SAID ANODE TERMINAL OF SAID SILICON-CONTROLLED RECTIFIER, ACROSS THE ALTERNATING VOLTAGE SOURCE; CIRCUIT MEANS FOR COUPLING THE MOTOR ARMATURE IN PARALLEL ACROSS SAID CAPACITOR; AND BIAS CONTROL MEANS COUPLED TO SAID GATE TERMINAL OF SAID SILICON-CONTROLLED RECTIFIER AND ADAPTED TO BE COUPLED ACROSS THE ALTERNATING VOLTAGE SOURCE; THE CIRCUIT ACTION BEING SUCH THAT DRIVING ENERGY IS SUPPLIED TO THE MOTOR ARMATURE DURING BOTH THE POSITIVE AND THE NEGATIVE HALF-CYCLES OF THE APPLIED ALTERNATING VOLTAGE WAVE, AND DURING EACH NEGATIVE HALF-CYCLE THE MECHANICAL LOAD ON THE MOTOR DETERMINES THE AMOUNT OF ENERGY DRAWN FROM SAID CAPACITOR INTO THE MOTOR ARMATURE AND THEREBY CHANGES THE POTENTIAL LEVEL AT SAID CATHODE TERMINAL OF SAID SILICON-CONTROLLED RECTIFIER SO AS TO PRECISELY DETERMINE THE POINT AT WHICH SAID SILICON-CONTROLLED RECTIFIER BECOMES CONDUCTIVE DURING THE NEXT SUCCEEDING HALF-CYCLE OF THE APPLIED VOLTAGE WAVE.