There is no voltage at the start of the diesel generator set. Is the entire unit broken? It is very likely that there is no magnetic field when starting the no voltage. The following solutions are available. 1. First look at the glossiness of the two slip rings. If there is no gloss, use a sand cloth to grind it until it becomes bright. If it doesn't work, take a very fine fuse and put the three-phase four-wire on the generator. "Connect two randomly (to make it short), then start the engine, the fuse will automatically blow, then the voltage will come up. 2. If you don't understand the diode, open an iron ring on the back cover of the generator, you can see the two slip rings, and then see the carbon sand. At this time, take a battery, you can use whatever size, then start the generator. Hold the positive and negative wires on the battery by hand, and then press and hold the two carbon sands corresponding to the slip ring, and then press and hold until the generator voltage rises. 3. If it still doesn't work, try changing the positive and negative terminals of the battery. If the voltage disappears immediately after removal, the diode is broken and the diode is replaced.