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Trouble Analysis and Elimination of Diesel Generator Unstable Frequency

Sep. 04, 2021

The rotational speed of the diesel generator is unstable when it is working, which is manifested in the high and low speed. This situation is more obvious at idling speed. In this article, Starlight Power Generation Equipment will give you a detailed introduction to the reasons for the unstable rotation of diesel generators and the troubleshooting methods as follows:


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1. The fuel system causes unstable frequency of diesel generators

(1) Failure analysis. When the diesel generator is in operation, if there is air, moisture, leakage in the fuel system, or the low-pressure oil circuit is blocked, it is easy to make the fuel supply intermittently or intermittently or the fuel supply is not smooth, resulting in unstable rotation of the diesel generator.

(2) Troubleshooting methods. First, observe whether there is leakage at each interface of the fuel system. If there is no leakage, loosen the bleed screw of the fuel injection pump and press the hand pump to remove the air in the low-pressure oil circuit. If there is no air in the low-pressure oil circuit, remove the oil inlet filter screen of the oil transfer pump for inspection. If the oil inlet filter screen of the oil transfer pump is not blocked, check whether the diesel filter or the oil tank inlet pipe is blocked or leaked.


2. The frequency of the diesel generator is unstable due to the fault of the governor

(1) Failure analysis. After the elastic force of the speed regulating spring in the diesel generator governor is weakened or the one-way thrust bearing is damaged, it is easy to cause the diesel generator speed to be unstable.

(2) Troubleshooting methods. Once the governor assembly of the fuel injection pump should be used for about 1000h, it should be calibrated on the fuel injection pump test bench. If the above-mentioned failure phenomenon occurs due to long-term failure to calibrate, as long as the fuel injection pump and governor assembly is sent to the pump calibration center for debugging, the malfunction of the diesel generator's rotational speed can be eliminated.


3. Fuel injection pump failure causes unstable frequency of diesel generator

(1) Failure analysis. The unevenness of the fuel supply of each cylinder of the fuel injection pump is too large, the internal plunger is stuck, the movement of the fuel volume adjustment rack is not flexible, and the fuel volume control sleeve fixing screw is loose, etc., all of which will make the diesel generator speed unstable.

(2) Troubleshooting methods. After the fuel injection pump is damaged, the maintenance personnel generally do not disassemble the fuel injection pump components at will, but should send it to the school pump center for repair or calibration by professionals.


Starlight Power has advanced testing equipment, modern production technology, professional manufacturing technology, perfect quality management system, and strong technical research and development capabilities. It can provide 3KW~2500KW various specifications of ordinary, automatic, four protection, automatic switching, low noise and mobile generator sets, high quality and low energy consumption to meet the diverse power needs of customers, and can also meet users with different voltages and different frequencies. It is required to create a parallel power supply system for multiple units. If you are interested in our product or any question on generator, welcome to send email to sales@dieselgeneratortech.com.

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