Counter e. m. f. speed control system

Claim 1

IN A D.C. MOTOR ENERGIZING CIRCUIT; A REGENERATIVE CONTROL CIRCUIT INCLUDING THE SERIES CONNECTION OF A LOAD RESISTOR AND A FIRST CONTROLLED RECTIFIER CONNECTED IN PARALLEL WITH SAID MOTOR, A SECOND CONTROLLED RECTIFIER IN PARALLEL WITH SAID MOTOR CIRCUIT, AND A CAPACITOR CONNECTED DIRECTLY BETWEEN THE ANODES OF SAID FIRST AND SECOND CONTROL RECTIFIERS; AND A FIRST CONTROL CIRCUIT CONNECTED TO THE GATE CIRCUIT OF SAID FIRST CONTROLLED RECTIFIER, AND A SECOND CONTROL CIRCUIT CONNECTED TO THE GATE CIRCUIT OF SAID SECOND CONTROLLED RECTIFIER; SAID FIRST CONTROL CIRCUIT INCLUDING COMPARATOR CIRCUIT MEANS CONNECTED TO SWITCHING MEANS; SAID SWITCHING MEANS TURNING ON SAID FIRST CONTROLLED RECTIFIER WHEN SWITCHED TO A CONDUCTIVE CONDITION; SAID COMPARATOR CIRCUIT BEING CONNECTED TO SAID SWITCHING MEANS AND SAID ENERGIZING CIRCUIT FOR COMPARING THE INPUT VOLTAGE TO THE MOTOR ARMATURE VOLTAGE AND RENDERING SAID SWITCHING MEANS CONDUCTIVE RESPONSIVE TO OVERSPEEDING OF SAID MOTOR; SAID SECOND CONTROL CIRCUIT NORMALLY SUPPLYING GATE CURRENT TO SAID SECOND CONTROLLED RECTIFIER FOR MAINTAINING SAID SECOND CONTROLLED RECTIFIER NORMALLY CONDUCTIVE; SAID SECOND CONTROLLED RECTIFIER CEASING CONDUCTION RESPONSIVE TO TURN ON OF SAID FIRST CONTROLLED RECTIFIER AND DISCHARGE OF SAID CAPACITOR; SAID SECOND CONTROL CIRCUIT INCLUDING TIME DELAY CIRCUIT MEANS WHEREBY A FIRING GATE CURRENT FOR SAID SECOND CONTROLLED RECTIFIER IS REESTABLISHED ONLY AFTER A PREDETERMINED TIME FROM THE TURN-OFF OF SAID SECOND CONTROLLED RECTIFIER; THE SUBSEQUENT TURN ON OF SAID FIRST CONTROLLED RECTIFIER TURNING OFF CONDUCTION OF SAID FIRST CONTROLLED RECTIFIER; SAID TIME DELAY CIRCUIT MEANS INCLUDING SECOND SWITCHING MEANS CONNECTED TO SAID GATE CIRCUIT OF SAID SECOND CONTROLLED RECTIFIER; SAID SWITCHING MEANS BEING NORMALLY CONDUCTIVE AND BEING RENDERED NON-CONDUCTIVE RESPONSIVE TO TURN ON OF SAID FIRST CONTROLLED RECTIFIER.