Apparatus for bench testing a governor

An apparatus for testing components of an electronic engine governor is disclosed. The governor to be tested has a speed control unit responsive to a control signal for producing a fuel control signal and an amplifier coupled to the speed control for compensating engine load, and may have a load computer for producing a load signal indicative of engine loading. A voltage controlled oscillator (VCO) in the test apparatus is adapted to be coupled to the speed controller for simulating engine speed as a variable frequency output in response to an input voltage. A summing node is adapted to be responsive to the output of the speed control unit and the load computer for producing a summed input control signal to the VCO. Substitute voltage and current signals are provided as input to the load computer to check the load computer operation. Droop and load-share switches provide means for coupling the output of the load computer to the input of the speed control unit to check the droop and load-share action of the governor. Additional switches provide for testing other functions such as change of frequency and automatic synchronizing. The entire apparatus is contained in one compact portable package and is adaptable to various manufacturer's equipment through the use of adapter-cable assemblies.