LEONARD W FINNELL
Engineers in Pittsburgh, PA

4032835, Jun 28, 1977

Mar 15, 1976

5/666813

Leonard W. Finnell - Forest Hills PA
Sigrud R. Petersen - North Huntingdon PA
Dale I. Gorden - North Versailles PA

Westinghouse Electric Corporation - Pittsburgh PA

H02P 914

322 86

An excitation system for a synchronous generator includes a conventional brushless exciter for providing base excitation for rated power output and a controlled source of direct current interconnected with the conventional brushless excitation system to supplement the base excitation. The supplementary excitation is supplied to the rotating field winding of the synchronous generator to provide forcing excitation to permit operation of the generator at power levels which exceed the generator's base power output level. In a preferred embodiment of the present invention, means operable to derive a control signal proportional to a predetermined function of the field winding excitation and of the power output of the generator is provided to control the magnitude and polarity of the supplemental excitation to permit operation of the synchronous generator at power levels which exceed its base power output level, to provide negative direct current excitation to permit fast-de-excitation of the generator, and to provide substantially zero supplemental excitation when the generator is operating at its base power output level.