Static speed control system for electric motors

Claim 1

IN A CONTROL SYSTEM FOR REGULATING THE SPEEDS OF A PLURALITY OF EACH MOTORS, THE COMBINATION OF: A PLURALITY OF SLAVE INVERTERS, EACH OF WHICH IS COUPLED TO AT LEAST ONE OF SAID MOTORS; MEANS FOR APPLYING D.-C. ENERGY TO EACH OF SAID SLAVE INVERTERS; A MASTER INVERTER COUPLED TO EACH OF THE SLAVE INVERTERS FOR DRIVING EACH SLAVE INVERTER AT A FREQUENCY RELATED TO THE OPERATING FREQUENCY OF THE MASTER INVERTER; A FUNCTION SELECTOR COUNTER HAVING AN INPUT CONNECTION FOR RECEIVING A SERIES OF TIMING SIGNALS, AND AN OUTPUT CONNECTIONS FOR ISSUING A SINGLE CONTROL SIGNAL RESPONSSIVE TO RECEIPT OF A GROUP OF TIMING SIGNALS TOTALLING A PREDETERMINED NUMBER, THE OUTPUT CONNECTION BEING COUPLED TO THE MASTER INVERTER TO REGULATE THE FREQUENCY OF OPERATION OF THE MASTER INVERTER, AND THUS OF EACH SLAVE INVERTER, IN RELATION TO THE FREQUENCY OF THE CONTROL SIGNALS PROVIDED BY THE FUNCTION SELECTOR COUNTER; AND MEANS FOR APPLYING A SERIES OF TIMING SIGNALS TO THE INPUT CONNECTION OF THE FUNCTION SELECTOR COUNTER.