Tips on how to fix the no voltage output fault of megohmmeter

The fault phenomenon is: when shaking the handle, it feels light, the megohmmeter needle does not deflect, short-circuit the output terminals E and L, the needle does not move, use the multimeter DC 500V gear to measure the E and L output terminals, and there is no voltage output when shaking the handle. Stop shaking the handle quickly, bend down and listen to the inside of the megohmmeter, and no sound of the generator rotor inertia rotation can be heard.

This kind of fault usually occurs in the speed governor. It is often caused by the spring of the speed governor breaking or the adjusting screw being loose, which causes the friction contact and the friction wheel to separate. Therefore, when the handle is shaken, the generator rotor is not driven, and the sound of the rotor rotating cannot be heard. Of course, there is no voltage output. For repair methods, please refer to Figure 5-24. When disassembling the megohmmeter, pay attention to the relative positions of each component, mark them and place them on a clean cloth or white paper for restoration and reset. Remove the housing, generator and speed governor in turn, and you will find that the spring of the speed governor is broken or the speed regulating screw is loose, causing the friction contact and the friction wheel to separate. After installing according to Figure 5-24, follow the reverse procedure of disassembly to put the speed governor, generator and housing in place.

Install the generator so that the rotor can rotate flexibly. Then carefully adjust the adjusting screw on the speed governor so that the speed governor does not slip. When the handle is shaken at 120r/min, the generator terminal voltage does not exceed 20% of the rated value.