Abstract: An output voltage control system for an electric generator having two field windings, wherein a rotary shaft of the generator is rotated by a power source such as an engine, for producing an output voltage. According to the invention, the control system includes a first control unit for supplying an electric current inversely proportionate to the output frequency of the generator to one of the field windings of the generator to produce a substantially constant output voltage for a stationay (fixed) load, and a second control unit for supplying an electric current derived from a portion of the output voltage produced at the generator output to the other of the field windings of the generator in the event of fluctuations in the generator load.