Controlled rectifier motor speed control system

Claim 1

IN A MOTOR SPEED CONTROL SYSTEM, IN COMBINATION; A FIRST RECTIFIER BRIDGE NETWORK HAVING INPUT AND OUTPUT TERMINALS; A SECOND BRIDGE NETWORK HAVING INPUT AND OUTPUT TERMINALS; CONTROLLED SEMICONDUCTOR RECTIFYING DEVICES LOCATED IN ADJACENT ARMS OF SAID FIRST RECTIFIER BRIDGE NETWORK AND BEING POLED SO AS TO CONDUCT TOWARDS A FIRST ONE OF SAID OUTPUT TERMINALS OF SAID FIRST RECTIFIER BRIDGE NETWORK; MEANS CONNECTING THE INPUT TERMINALS OF SAID SECOND BRIDGE NETWORK ACROSS THE OUTPUT TERMINALS OF SAID FIRST BRIDGE NETWORK; A MOTOR TO BE CONTROLLED FOR CONSTANT SPEED OPERATION THE ARMATURE OF SAID MOTOR BEING LOCATED IN ONE ARM OF SAID SECOND RECTIFIER BRIDGE NETWORK; A SOURCE OF REFERENCE VOLTAGE; MEANS TO COMPARE A VOLTAGE FROM SAID SOURCE OF REFERENCE VOLTAGE WITH A VOLTAGE DERIVED FROM THE ARMATURE OF THE MOTOR TO BE CONTROLLED, AND INDICATIVE OF THE SPEED OF THE MOTOR WHEREBY A CONTROL VOLTAGE IS DETERMINED; A MAGNETIC AMPLIFIER; MEANS TO IMPRESS SAID CONTROL VOLTAGE UPON A CONTROL WINDING OF SAID MAGNETIC AMPLIFIER TO CONTROL THE PHASE AT WHICH THE SAID MAGNETIC AMPLIFIER FIRES;