When diesel generator sets operate, in standby power or prime power, they perhaps encounter some mechanical or electrical problems which could cause them to either shutdown or degrade their performance. Generator set problems vary from simple electrical wiring faults to major engine problems. Trouble-shooting in the Generator sets can simply answer these questions: what caused this alarm, or what caused this shutdown or what caused this erratic behavior. Trouble-shooting is a process of collecting the information and defining the problem. After defining the problem, list all the possible causes of the problem and finally select the solution to eliminate the problem, as well as taking the economics and reliability into consideration.