Electrical apparatus for initial and short circuit excitation of generators

Claim 1

AN EXCITATION SYSTEM FOR A SELF-EXCITED DYNAMOELECTRIC MACHINE HAVING A FIELD WINDING AND OUTPUT TERMINALS DISPOSED TO SUPPLY ELECTRICAL CURRENT TO LOAD CONDUCTORS, COMPRISING FIRST MEANS APPLYING A POTENTIAL TO SAID FIELD WINDING WHEN SAID DYNAMOELECTIC MACHINE IS PRODUCING A POTENTIAL AT ITS OUTPUT TERMINALS, SECOND MEANS COMPRISING SEMICONDUCTOR SWITCHING MEANS HAVING MAIN ELECTRODES AND A CONTROL ELECTRODE, THIRD MEANS PROVIDING A SOURCE OF POTENTIAL, SAID THIRD MEANS AND THE MAIN ELECTRODES OF SAID SECOND MEANS BEING CONNECTED IN SERIES CIRCUIT RELATION WITH SAID FIELD WINDING, FOURTH MEANS APPLYING A FIRST SIGNAL TO THE CONTROL ELECTRODE OF SAID SECOND MEANS WHEN SAID DYNAMOELECTRIC MACHINE IS STARTED SAID FIRST SIGNAL SWITCHING SAID SECOND MEANS TO A CONDUCTIVE STATE TO CONNECT SAID THIRD MEANS WITH SAID FIELD WINDING AND ALLOW CURRENT TO FLOW FROM SAID THIRD MEANS THROUGH SAID FIELD WINDING AND ENABLE SAID SELF-EXCITED, DYNAMOELECTRIC MACHINE TO PRODUCE AN OUTPUT POTENTIAL, SAID SEMICONDUCTOR SWITCHING MEANS SWITCHING FROM THE CONDUCTIVE STATE TO A NON-CONDUCTIVE STATE TO REDUCE THE CURRENT FLOW FROM SAID THIRD MEANS TO ZERO WHEN THE POTENTIAL FROM SAID FIRST MEANS EXCEEDS THE POTENTIAL OF SAID THIRD MEANS, FIFTH MEANS APPLYING A SECOND SIGNAL TO THE CONTROL ELECTRODES OF SAID SECOND MEANS WHEN THE CURRENT IN THE LOAD CONDUCTOR REACHES A PREDETERMINED SHORT CIRCUIT MAGNITUDE, SAID SECOND SIGNAL SWITCHING SAID SECOND MEANS BACK TO THE CONDUCTIVE STATE TO AGAIN CONNECT SAID THIRD MEANS WITH SAID FIELD WINDING AND ALLOW CURRENT TO FLOW FROM SAID THIRD MEANS THROUGH SAID FIELD WINDING.