Electrical apparatus

Claim 1

A REGULATING SYSTEM FOR A SYNCHRONOUS MACHINE HAVING AN EXCITATION FIELD WINDING AND OUTPUT TERMINALS, COMPRISING: VECTOR SUMMING TRANSFORMER MEANS INCLUDING FIRST AND SECOND PRIMARY WINDINGS AND SECONDARY WINDINGS; INDUCTIVE REACTOR MEANS CONNECTED IN CIRCUIT RELATION WITH SAID OUTPUT TERMINALS AND SAID FIRST PRIMARY WINDING PRODUCING A FIRST CURRENT RESPONSIVE TO THE OUTPUT VOLTAGE OF SAID SYNCHRONOUS MACHINE AND LAGGING THE LINE TO NEUTRAL VOLTAGE OF SAID SYNCHRONOUS MACHINE BY SUBSTANTIALLY NINETY DEGREES; SAID SECOND PRIMARY WINDING OF SAID VECTOR SUMMING TRANSFORMER MEANS PRODUCING A SECOND CURRENT RESPONSIVE TO THE LINE CURRENT OF SAID SYNCHRONOUS MACHINE; SAID FIRST AND SECOND CURRENTS COMBINING VECTORIALLY IN SAID VECTOR SUMMING TRANSFORMER MEANS AND PRODUCING A THIRD CURRENT IN SAID SECONDARY WINDINGS HAVING A MAGNITUDE GREATER THAN THE EXCITATION CURRENT REQUIRED BY SAID FIELD WINDING: RECTIFIER MEANS CONNECTED IN CIRCUIT RELATION WITH SAID SECONDARY WINDINGS APPLYING SAID THIRD CURRENT TO SAID FIELD WINDING; MEANS PRODUCING A REFERENCE VOLTAGE; MEANS PRODUCING AN ERROR SIGNAL RESPONSIVE TO THE DEVIATION OF THE OUTPUT VOLTAGE OF SAID DYNAMOELECTRIC MACHINE FROM SAID REFERENCE VOLTAGE; STATIC SWITCHING MEANS CONNECTED IN PARALLEL CIRCUIT RELATION WITH THE SECONDARY WINDINGS OF SAID VECTOR SUMMING TRANSFORMER MEANS AND RESPONSIVE TO SAID ERROR SIGNAL FOR BY-PASSING A PORTION OF SAID THIRD CURRENT APPLIED TO SAID FIELD WINDING SO AS TO MAINTAIN THE OUTPUT OF SAID DYNAMOELECTRIC MACHINE AT A PREDETERMINED VALUE; MEANS RESPONSIVE TO THE OUTPUT CURRENT OF SAID SYNCHRONOUS MACHINE FOR PROVIDING A LIMITING SIGNAL WHEN A SHORT CIRCUIT OCCURS AT THE OUTPUT OF SAID SYNCHRONOUS MACHINE; AND MEANS FOR APPLYING SAID LIMITING SIGNAL TO SAID STATIC SWITCHING MEANS FOR BY-PASSING A PORTION OF SAID THIRD CURRENT APPLIED TO SAID FIELD WINDING SO AS TO MAINTAIN THE OUTPUT CURRENT OF SAID SYNCHRONOUS MACHINE AT A PRETERMINED VALUE.