GB849605A - Improvements in or relating to the excitation and automatic voltage regulation of alternators - Google Patents

Abstract

849,605. Exciting alternators; automatic voltage control systems. GENERAL ELECTRIC CO. Ltd. June 23, 1959 [July 23, 1958], No. 23741/58. Addition to 831,698. Classes 35 and 38 (4). The alternator compounding arrangement described in the parent Specification is rendered more accurate and rapid by the use of an additional constant voltage or current supply in the voltage component control circuit. In the form shown, the controller 12 which operates on the voltage component of excitation through a saturable reactor 10 to make secondorder corrections in the line voltage, is supplied with a steady A.C. voltage from an auxiliary permanent magnet generator 13. The controller is preferably of the neon reference and magnetic amplifier type, and according to this invention the magnetic amplifier is supplied from the alternator 13 instead of from the main machine as in the parent Specification. This renders the magnetic amplifier insensitive to transients in the main machine. Preferably the alternator 13 is of high frequency and is coupled to the main machine. In a modification (not shown) the saturable reactor 10 is saturated by an additional D.C. control-winding fed with constant current from a D.C. generator or an A.C. generator and rectifier. The D.C. control winding 11 fed by the controller 12 opposes the additional winding and serves to de-saturate the reactor 10. This arrangement also improves the transient response, and makes it possible for the controller 12 to be omitted for low-accuracy regulation, or a part of the additional control winding to be fed from the alternator output through a transformer and rectifier instead of using the controller 12.