Armature current limiting speed control systems for electric motors

Claim 1

A CONTROL SYSTEM FOR OPERATING A MOTOR FROM A PULSATING POWER SOURCE AT SELECTED SPEEDS, SAID CONTROL SYSTEM COMPRISING: A MOTOR HAVING AN ARMATURE AND A FIELD WINDING, A PHASE CONTROL MEANS ADAPTED FOR CONNECTION TO THE POWER SOURCE AND INCLUDING A SOLID STATE CONTROL DEVICE HAVING AN ANODE, A CATHODE AND A GATE, A FIRING SIGNAL SOURCE FOR FIRING SAID CONTROL DEVICE AT A SELECTED PHASE ANGLE, SAID SIGNAL SOURCE INCLUDING A SEMICONDUCTOR DEVICE SWITCHABLE FROM A HIGH IMPEDANCE CONDITION TO A LOW IMPEDANCE CONDITION AND ENERGIZED FROM SAID POWER SOURCE, A CAPACITOR COUPLED WITH SAID SEMICONDUCTOR DEVICE, THE VOLTAGE LEVEL ON SAID CAPACITOR CONTROLLING THE SWITCHIG OF SAID SEMICONDUCTOR DEVICE FROM SAID HIGH IMPEDANCE CONDITION TO SAID LOW IMPEDANCE CONDITION, CIRCUIT MEANS CONNECTING SAID ARMATURE AND SAID CONTROL DEVICE IN SERIES CIRCUIT AND INCLUDING A CONNECTION JOINING ONE SIDE OF THE ARMATURE WITH THE ANODE OF SAID CONTROL DEVICE, A FIRST UNIDIRECTIONAL CONDUCTING DEVICE CONNECTED IN CIRCUIT WITH SAID CAPACITOR AND WITH ONE END OF SAID ARMATURE, SAID FIRST UNIDIRECTIONAL CONDUCTING DEVICE BEING POLED TO DIVERT CURRENT FROM SAID CAPACITOR AND DELAY THE FIRING ANGLE OF SAID CONTROL DEEVICE, A SECOND UNIDIRECTIONAL CONDUCTING DEVICE CONNECTED IN SHUNT WITH SAID ARMATURE AND BEING POLED TO CONDUCT THE INDUCTIVE DECAY CURRENT OF THE ARMATURE, SAID FIRST UNIDIRECTIONAL CONDUCTING DEVICE BLOCKING CURRENT WHEN SAID SECOND UNIDIRECTIONAL CONDUCTING DEVICE CONDUCTS CURRENT AND SAID INTERVAL OF CONDUCTION OF SAID SECOND DEVICE INCREASING AS THE ARMATURE CURRENT INCREASES THEREBY COMPENSATING FOR TORQUE CHANGES BY SUPPLING INCREASED POWER TO THE ARMATURE.