Starting a gas turbine by using an exciter dynamo as the starting motor

Claim 1

AN ARRANGEMENT FOR STARTING UP A POWER COMPRISING A PRIME MOVER SUCH AS A GAS TURBINE COUPLED TO A SYNCHRONOUS GENERATOR FOR DRIVING THE ROTOR ELEMENT THEREOF AND AN EXCITER GENERATOR FOR SUPPLYING FIELD CURRENT TO THE ROTOR OF SAID SYNCHRONOUS GENERATOR, THE ROTOR OF SAID EXCITER GENERATOR BEING ALSO COUPLED TO SAID GAS TURBINE, THE IMMPROVEMENT WHEREIN A RECTIFIER SYSTEM IS SUPPLIED FROM AN ALTERNATING CURRENT SOURCE, THERE BEING A VARIABLE IMPEDANCE CHOKE IN THE CIRCUIT CONNECTIONS BETWEEN SAID RECTIFIER SYSTEM AND ITS ALTERNATING CURRENT SUPPLY SOURCE AND WHEREIN FOR STARTING PURPOSES THE DIRECT CURRENT OUTPUT FROM SAID RECTFIER SYSTEM IS SUPPLIED TO THE ROTOR OF SAID EXCITER GENERATOR IN SERIES WITH AN AUXILIARY FIELD WINDING THEREOF WHEREBY TO CAUSE IT TO OPERATE TEMPORRILY AS A SERIES MOTOR, THERE BEING A SWITCH PROVIDED BETWEEN THE ROTOR OF SAID EXCITER GENERATOR AND THE ROTOR OF SAID SYNCHRONOUS MACHINE FOR DISCONNECTION DURING THE START-UP AND A SECOND SWITCH BETWEEN THE DIRECT CURRENT OUTPUT SIDE OF SAID RECTIFIER SYSTEM AND THE ROTOR OF SAID EXCITER GENERATOR WHICH IS CLOSED ONLY DURING THE START-UP.