Why Perkins Generator Frequency Is Lower Than 50Hz

Jul. 26, 2021

Normally Perkins diesel generator frequency is 50Hz, but after it starting, the generation frequency is lower than 50Hz, what is the problem?


Although it seems that there is an internal problem in Perkins diesel generator set or the control part of the generator. In fact, it is also due to the fuel supply system of the diesel engine or the mechanical failure of the diesel engine. So that the power generation frequency cannot reach 50Hz after the speed of the diesel generator set fails to reach the rated speed.


There are seven reasons for the failure that the frequency cannot reach 50Hz after Perkins diesel generator set is started:


(1) Individual cylinders of the diesel generator set have faults, work poorly or do not work.

(2) The low-pressure oil circuit of diesel generator set has been blocked.

(3) The oil supply quantity of the high-pressure oil pump of the diesel generator set is inconsistent with the specified requirements of the unit, or some internal plungers of the high-pressure oil pump have been stuck.

(4) Air enters the oil circuit of the diesel generator set.

(5) During the overhaul, the connecting rod bolt of the diesel generator set was too hard, resulting in too tight connection between the connecting rod pad and the journal.

(6) The oil transfer pump of the diesel generator set is faulty and does not work well.

(7) Individual fuel injectors of diesel generator set are no longer injected.

 Perkins generator set

Find the key to the problem, in order to really solve the problem, how to sort out all parts of the problem?


1.Check the working situation of cylinder. After running speed of diesel generator is about 700r/min, check the temperature of exhaust pipes of each cylinder by hand. If the temperature of cylinder is different from others, it is a problem of cylinder. If the temperature of cylinder is the same, it is not a problem of cylinder.


2.Check diesel oil pressure. First, remove the oil outlet pipe of the oil pump, block the oil outlet hole with one hand, and press the handle of the oil pump repeatedly with the other hand to observe whether the oil pressure is normal.


3.Check high pressure oil pump. Remove the side cover plate of the high-pressure oil pump, run the diesel generator set, then carefully observe whether there is any leakage of diesel oil between the high-pressure oil pump and the pump body. If there is oil leakage, it shows that the clearance between the plunger and the plunger sleeve of the oil pump channels oil, which leads to insufficient oil supply in the low-pressure oil pipeline, power decline. So the speed can't reach the rated speed.

4.Check whether there is impurity or not. Check the filter screen of the oil pump after 100kw Perkins diesel generator shout down. If there is no impurity, the operation will be normal.


5.Check replacement. After replacing the new oil pump, start the diesel generator and observe whether the tachometer is displayed at 1500r/min after the speed is raised to the standard speed. After exciter excitation, the frequency of the generator set will be displayed at 50.5Hz, at time, if reduce the speed, the frequency will be displayed at 50Hz. Then the diesel generator set will be able to operate normally.


When there is problem in diesel generator, if you do not have technology and knowledge in generator faults, it is better not to disassemble the generator set by yourself, must operate under professional engineers.


In order to let our generator set run better, maintenance is also important.


Recently generator enterprises put forward new ideas for daily maintenance: taking preventive test as the center, replacing parts, overhauling or replacing three filters should be based on full load test machine. In order to discover the potential safety hazards of gensets in operation, preventive test refers to the periodic full-load test of gensets that have been put into operation in accordance with the specified test conditions, test items and test cycles, It can simulate the real situation of power failure and provide objective basis.


New methods of daily maintenance:

1.Inspection of four leakages, surface, starting battery, oil and fuel of diesel Generator Set.

2.No load monthly, the time of no load can not over 5 minutes.

3.Full-load test of diesel generating sets and power mutation test.

4.Replace the three filters according to the running time of the diesel generator.

5.Clean and improve the environment of generator room.

6.After replacement of spare parts and the three filters, or overhaul, the full-load test machine must be judged.

Dingbo Power is a manufacturer of electric generators, founded in 2006, who can supply 25kva-3125kva power generator sets. If you have purchasing plan, welcome to call us directly by mobile phone +8613481024441, we will work with you.

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