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38 Common Problems of Diesel Generator Sets Part 2

Jan. 07, 2022

Let's continue to learn about common problems with diesel generators.


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21. What are the noise sources of diesel generator sets?


Intake noise, exhaust noise and cooling fan noise.

The working combustion noise of the combustion chamber, the mechanical noise of the friction of engine parts.

The noise generated by the high-speed rotation of the rotor in the electromagnetic field.


22. Start-up skills of diesel generator set in winter.


Preheating: The cooling system can heat water and heat the oil pan with a heat source.

Improve air tightness: The injector can be removed, and 30-40ml of oil is added to each cylinder to enhance the sealing performance of the cylinder and increase the pressure during compression.

Cranking: Before starting, crank the crankshaft to make it run easily before starting.


23. What is the function of the piston ring of a diesel generator set?


Heat transfer

Control oil

Supporting effect

Keep air tight


24. How many ways and sequence are there for the running-in of the new machine?


Cold run-in first, manual rotation, or external force drives the crankshaft to rotate.

After thermal break-in, no load break-in.

25. The reason for the deterioration of engine oil?


Use the oil with the wrong grade and the quality is not up to the standard.

The operating condition of the unit is not good, such as gas blow-by, oil blow-by, over-fitting clearance, over-high oil temperature, etc.

The unit often runs at low temperatures.

The exhaust gas enters the oil pan and condenses into moisture and acidic substances.

The oil filter is too dirty, the filter is leaking, and the oil is not filtered by the filter.

26. What is the role of the oil pump?


The function of the oil pump is to supply enough oil to the lubrication system to effectively lubricate each moving part. At present, gear and rotor oil pumps are widely used in diesel engines.


27. What is the function of the governor?


The speed governor should be able to adjust the fuel supply sensitively according to the changes of the external load to maintain the stability of the speed. It must have two basic parts: sensing elements and actuators.


28. What is the function of the automatic voltage stabilizer?

The automatic voltage regulator (AVR) keeps the generator close to a stable voltage from no load to full load. This AVR has a voltage-frequency (Hertz) proportional characteristic, which can correctly adjust and reduce the output voltage when the rated speed is reduced. This feature helps protect the engine when a large load is suddenly added.

29. How to maintain the battery?

For frequently used machines, the battery generally does not cause problems, as long as the policy is maintained, if it is a battery that has not been used for a long time, its power should be checked and charged regularly, and it should be charged once every 12 weeks ( 8 weeks in the tropics).

30. Under what circumstances does the unit automatically delay shutdown?

If the fuel level is too low, the water temperature is too high, the water level is too low, the load is overloaded, and the start fails, the corresponding signal will be issued.

31. Under what circumstances does the unit make an emergency shutdown?

Overspeed, short circuit, lack of phase, excessive voltage, loss of voltage, low frequency

32. Under what circumstances does the unit automatically send out an audible and visual alarm signal?

Oil pressure is too low, water temperature is too high, water level is too low, overload, start failure, overspeed, short circuit, phase loss, overvoltage, loss of voltage, low frequency, start battery voltage is too low, start battery voltage is too high, low oil The alarm system of the bit and the unit has relay contacts.

33. What is the type of oil filter for diesel generator set?

Mechanical separation

Centrifugal separation

Magnetic adsorption

34. What is the reason for the smaller compression ratio?

The position of the piston at the end of compression is low: related parts are worn, deformed, etc.

The volume of the combustion chamber becomes larger: the valve seat ring is worn, the top of the piston is sunken, the cylinder head gasket is too thick, etc.

35. What are the automatic control functions of diesel generator sets?

Automatic heating device

Automatic adjustment of diesel engine speed

Charging system

Instrument system from

protective device

Starting system

36. How does the automatic heating device work?

On diesel engines, an automatic cooling water heating device is generally installed, so that when the generator set is in the standby state, the diesel engine should be in a warm state, so that the generator set can start the generator set and work with load within 15s when the mains power is lost.

Diesel engine automatic heating device. When the water temperature is lower than 30 degrees Celsius, the thermostat contact is turned on, KM is closed, and the heater EH works. When the water temperature rises to 50 degrees Celsius, the thermostat contacts are disconnected, KM is released, and the heater EH is powered off.

In addition to the cooling water heating device, there are also oil heating devices and battery heaters.

37. How to observe the power of the maintenance-free battery with the naked eye?

There is generally a transparent observation port above the battery. If we look down from above, we can see the color inside. If it is green, it means that the battery is fully charged. If it is white, it means that it needs to be charged. If it is black, it means that the battery is fully charged. Need to be replaced.

38. Why is there a white solid on the battery terminal?

This is a normal phenomenon. The white solid is the product of the oxidation of the battery terminal and the air, and it will disappear if it is washed with boiling water during cleaning.

All of the above are common questions about diesel generators. If there is anything you need to know, welcome to visit our website or send an email to sales@dieselgeneratortech.com.

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