Reverse Power in Gas & Diesel Genset

Maybe you hooked the speed controller up backwards.

1. Governor out of adjustment.
2. Fuel delivery problem:
a. Fuel supply nearly empty.
b. Fuel filter plugged, or other restriction in line.
c. Fuel pump malfunctioning.
d. Injector pump stroke not properly set.
e. Worn injectors.
3. Voltage regulator setting out of match with other gensets.

Your question does not make sense to me. Both four stroke internal combustion engine (ICE) types of gasoline and diesel must have their crank shafts spinning in only one direction or they do not produce mechanical power. This is why an ICE powered vehicle normally has a reverse gear configuration in the transmission. The AC generator attached to the engine crankshaft does not care which direction the rotor spins. The three phase sequence will be flipped but that's not a significant problem.

So I suspect you wish to ask something else, but what? You might want to know about the reserve power of a generator set. You might want to know about the back EMF effect from a motor attached to a generator effect. You might even want to know about something else. If you clarify your question then somebody can help you.

This can occur when a number of generators are running in parallel and one motor runs underspeed, for whatever reason, and causes the generator to then act as a motor consuming electricity....