The Woodward 2301A Full Authority Speed Control sets the speed or load of a diesel engine, gas engine, steam turbine, or gas turbine according to the demand of a process or a computer control signal. The unit provides isochronous operation, with droop control available through an externally-wired potentiometer. The isochronous mode is used for constant speed of the controlled prime mover as long as it is able to provide power to satisfy the load. Droop control is provided when parallel-bus operation is required.