Motor control system responsive to armature c. e. m. f.

Claim 1

A MOTOR CONTROL SYSTEM FOR OPERATING A MOTOR FROM A POWER SOURCE, SAID SYSTEM COMPRISING: A MOTOR HAVING AN ARMATURE AND A SHUNT FIELD WINDING, SAID SHUNT FIELD BEING CONNECTED ACROSS SAID POWER SOURCE, A PHASE CONTROL CIRCUIT INCLUDING A CHARGING CAPACITOR AND AT LEAST ONE SOLID STATE SWITCHING DEVICE HAVING AN ANODE, A CATHODE AND A GATE, CIRCUIT MEANS INCLUDING AN ELECTRICAL CONNECTION JOINING THE CATHODE OF SAID DEVICE IN CIRCUIT WITH THE ARMATURE, SAID CIRCUIT MEANS CONNECTING SAID DEVICE AND ARMATURE ACROSS THE POWER SOURCE, CURRENT CONTROL MEANS CONNECTED IN CIRCUIT WITH SAID CHARGING CAPACITOR FOR CONTROLLING THE CHARGING CURRENT SUPPLIED TO SAID CHARGING CAPACITOR, THE RATE AT WHICH CHARGING CURRENT IS SUPPLIED TO THE SAID CHARGING CAPACITOR DETERMINING THE POINT IN EACH CYCLE OF SAID POWER SOURCE WHEN SAID SOLID STATE SWITCHING DEVICE IS FIRED, SAID CONTROL MEANS INCLUDING CIRCUIT CONNECTIONS FOR DIVERTING CURRENT FROM SAID CHARGING CAPACITOR, A VARIABLE IMPEDANCE MEANS INCLUDING A TRANSISTOR TO LIMIT THE DIVERSION OF SAID CURRENT, SAID TRANSISTOR HAVING A BASE, EMITTER AN COLLECTOR, SAID EMIT-