Abstract:
A SYSTEM FOR AUTOMATICALLY CONNECTING A SECOND ALTERNATING CURRENT INDUCTION MOTOR IN PARALLEL WITH A FIRST OPERATING ALTERNATING CURRENT INDUCTION MOTOR ACROSS A COMPATIBLE ALTERNATING CURRENT SUPPLY POTENTIAL IN RESPONSE TO AN EXTERNAL DEMAND. THE PARALLEL COMBINATION OF A PHASE WINDING OF BOTH MOTORS IS CONNECTED IN SERIES WITH A NETWORK OF TWO SERIES CONNECTED, OPPOSITELY POLED SILICON CONTROLLED RECTIFIERS CONNECTED IN PARALLEL WITH TWO SERIES CONNECTED, OPPOSITELY POLED DIODES ELECTRICALLY CONNECTED AT THE JUNCTION. ELECTRICAL TRIGGER SIGNALS, PRODUCED BY A SPEED CONTROL CIRCUIT, ARE APPLIED ACROSS THE GATE-CATHODE ELECTRODES OF BOTH SILICON CONTROLLED RECTIFIERS OF EACH NETWORK DURING EACH POTENTIAL HALF CYCLE. A SWITCHING CIRCUIT, RESPONSIVE TO OPERATING MOTOR LOAD, ENERGIZES A RELAY WHICH COMPLETES AN ENERGIZING CIRCUIT FOR THE STARTING CONTACTOR OF THE SECOND MOTOR AND DEENERGIZES THE RELAY TO REMOVE THE SECOND MOTOR WHEN THE DEMAND NO LONGER EXISTS.