The
throttle of an engine in an engine driven generator
system operating under an intermittently
heavy load, as in supplying current to a welder, is controlled such that successive control signals sent to a
throttle actuator for adjusting the engine
throttle position are inhibited until at least a predetermined time has elapsed since the last preceding adjustment to the throttle. This procedure ensures that, as to each incremental adjustment to the throttle, the engine has
sufficient time to respond, thereby preventing over-speeding or stalling the engine. The throttle
actuator may be a
stepper motor which is stepped by throttle position change signals from a processor which monitors engine speed and generator load to determine whether the throttle should be adjusted and, if so, in which direct. Alternatively, the throttle
actuator may be a solenoid pulling against a spring in accordance with the
average current through the solenoid coil. In this embodiment, the processor causes
pulse width modulated signals to be applied across the solenoid coil with throttle position changes being reflected in changes to the width of the pulses, such changes in the pulse width being delayed for at least the predetermined time since the last preceding adjustment to the throttle.