Semiconductor control circuit with moving iron core

Claim 1

A CONTROL CIRCUIT FOR AN ELECTRIC MOTOR INCLUDING A MAIN WINDING AND A STARTING WINDING ANGULARLY DISPLACED FROM EACH OTHER IN A STATOR CORE AND INDUCTIVELY COUPLED TO A ROTOR, COMPRISING: POWER CIRCUIT MEANS FOR CONNECTING SAID MAIN WINDING TO A POWER SUPPLY; SENSING TRANSFORMER MEANS, HAVING A PRIMARY WINDING COUPLED TO SAID POWER CIRCUIT MEANS AND HAVING A SECONDARY WINDING FOR DEVELOPING A CONTROL SIGNAL; STARTING CIRCUIT MEANS, FOR CONNECTING SAID STARTING WINDING TO A POWER SUPPLY; A SIGNAL-CONTROLLED SEMICONDUCTOR GATE DEVICE, HAVING INPUT AND OUTPUT ELECTRODES CONNECTED IN SERIES IN SAID STARTING CIRCUIT MEANS, AND HAVING A CONTROL ELECTRODE CONNECTED TO SAID SECONDARY WINDING OF SAID SENSING TRANSFORMER MEANS, FOR OPENING AND CLOSING SAID STARTING CIRCUIT MEANS IN RESPONSE TO SAID CONTROL SIGNAL; A MAGNETIC CORE LOCATED WITHIN THE MAGNETIC FIELD OF SAID PRIMARY WINDING AND MOVABLE FROM A FIRST POSITION IN WHICH SAID CORE AFFORDS ONLY LIMITED COUPLING BETWEEN SAID WINDINGS TO A SECOND POSITION IN WHICH SAID CORE AFFORDS SUBSTANTIALLY GREATER COUPLING BETWEEN SAID WINDINGS WHENEVER THE LOAD CURRENT TO SAID MAIN WINDING EXCEEDS A FIRST THRESHOLD AMPLITUDE; AND MEANS FOR RESTORING SAID MAGNETIC CORE TO ITS FIRST POSITION WHENEVER THE MOTOR LOAD CURRENT FALLS BELOW A SECOND THRESHOLD AMPLITUDE.