Automatic control on auxiliary voltage for engine driven welder

A self-contained welding power supply capable of, upon termination of welding operation, automatically setting a control signal for auxiliary power is provided. The power supply comprises an engine, a generator driven by the engine, and an excitation system that controls power output of the generator. The excitation system includes an output controller and a DC controller. The output controller includes circuitry that generates a field voltage control signal to be sent to the DC controller to regulate DC power going to field windings of the generator. Upon termination of the welding operation, the field voltage control signal is automatically set to a value appropriate for the auxiliary system operation.