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What Happens If We Ignore the Small faults of Generator Set?

Apr. 21, 2020

Today, Starlight Power will talk about the harm caused small faults and untimely maintenance for diesel generator sets.


As we all know, the service life of diesel generator set is closely related to correct operation and reasonable use. When the genset breaks down, it needs to be repaired in time, but some users maybe think that some minor faults do not affect the use of the genset, so they ignore them, and they will not repair until the unit "strikes", which is extremely incorrect. Why? 


1.If we do not maintain the small faults of diesel generators timely, there will be short-circuit between turns of stator winding, which will generate ring current under the action of short-circuit voltage, which may cause turn to turn short circuit to develop into single-phase ground short circuit and phase to phase short circuit. When the multi-phase phase to phase short circuit occurs in the stator winding, it is the most harmful to the unit, and the short circuit current will cause the unit to burn down.

 Shangchai generator

2.If the generator set is not maintained in time, the excitation current will drop sharply or disappear. The unit will absorb a lot of reactive power from the system, and the unit will change from synchronous operation to asynchronous operation. The system voltage will also drop, which will cause the system to collapse in serious cases.

3.If there is a small fault that is not repaired in time, the excitation circuit will be grounded. The excitation circuit of the unit is grounded in one point and two points respectively. Generally speaking, when the excitation circuit is grounded at one point, there is no serious harm to the unit. However, if the maintenance is not carried out in time, two-point grounding may occur, which will destroy the balance of the rotor flux, cause strong vibration of the generator, and finally burn the rotor winding.

4.If the diesel generator set is not maintained in time, the unit will over-voltage. When the unit is in operation and load rejection occurs suddenly, over-voltage may occur due to the large inertia of the speed control system, resulting in the breakdown of the insulation layer of the unit.

5.If the unit fails to be repaired in time, the unit will be overloaded. Generator overload refers to the operation of the unit beyond the rated capacity. If it is a short-term overload operation, it will generally cause the stator winding temperature rise and accelerate the aging of the insulation part, affecting the normal service life of the unit. If it is overloaded for a long time, it is possible to burn down the stator winding, and the final result is that the unit cannot generate electricity.

6.If the small fault of the unit is not repaired in time, the stator will be over-current. Stator overcurrent is generally caused by external short circuit or system oscillation. When it is slight, the stator temperature will rise to accelerate the aging of the insulation part of the winding; when it is serious, other major faults will occur.


In order to prevent large failures of diesel generator, the user should stop the unit immediately after finding small failures, check and eliminate the failures, and put the unit into use after repair. In addition, the corresponding protection device can be set on the diesel generator set to play a better role in protecting the diesel generators.


Starlight Power is diesel generator factory in China, founded in 1974. We have focused on high quality product for more than 43 years, covering Cummins, Volvo, Perkins, Yuchai, Shangchai, Deutz, Ricardo, Weichai, Wuxi etc. Power range is 25kva-3125kva, welcome to contact us for inquiry if you have purchase plan.

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