Part three: 30 Common Questions of Diesel Genset

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

Intake noise, exhaust noise and cooling fan noise.

Combustion noise of combustion chamber and mechanical noise of engine parts friction.

Noise caused by high-speed rotation of rotor in electromagnetic field.

22. Starting 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: remove the fuel injector and add 30 ~ 40ml oil into each cylinder to enhance the sealing performance of the cylinder and improve the pressure during compression.

Turning: crank the crankshaft before starting to make it run easily before starting.

23. What is the function of piston ring of diesel genset?

Heat transfer effect.

Control oil.

Supporting function.

Maintain air tightness.

24. How are the running in modes and sequences of the new machine?

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

After thermal running in, no-load running in.

25. Why is the engine oil deteriorated?

Use oil with wrong brand and unqualified quality.

The operation condition of the unit is not good, such as gas and oil channeling, excessive matching clearance and high oil temperature.

The unit often operates at low temperature.

The exhaust gas enters the oil pan and condenses into water and acids.

The oil filter is too dirty, the filter leaks, and the oil is not filtered through the filter.

26. What is the function of 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 type and rotor type oil pumps are widely used in diesel engines.

27. What is the function of the governor?

The Governor shall be able to sensitively adjust the oil supply according to the change of external load, so as to maintain the stability of speed. It must have two basic parts: sensing element and actuator.

28. What is the function of automatic voltage regulator?

Automatic voltage regulator (AVR) enables the generator to closely maintain a stable voltage from no load to full load. The AVR has a voltage frequency (Hz) positive proportional characteristic, which can correctly adjust and reduce the output voltage when the rated speed is reduced. This feature helps to protect the engine when a large load is suddenly added.

29. Battery maintenance?

For the frequently used machine, the battery will generally not have problems, as long as the maintenance of the policy is well done. If the battery has not been used for a long time, its power shall be checked and charged regularly, and it shall be charged every 12 weeks (8 weeks in tropical areas).

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

The fuel level is too low, the water temperature is too high, the water level is too low, overload, startup failure, and send corresponding signals.

31. Under what circumstances does the unit stop in an emergency?

Overspeed, short circuit, phase loss, high voltage, voltage loss and low frequency.

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

Low oil pressure, high water temperature, low water level, overload, startup failure, overspeed, short circuit, phase loss, high voltage, voltage loss, low frequency, low startup battery voltage, high startup battery voltage, low oil level and the alarm system of the unit have relay contacts.

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

Mechanical separation.

Centrifugal separation.

Magnetic adsorption.

34. What is the reason why the compression ratio becomes smaller?

The position of piston at the end of compression is low: relevant parts are worn and deformed.

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

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

Automatic heating device.

Automatic regulation of diesel engine speed.

Charging system.

Instrument system.

Protector.

Starting system.

36. How does the automatic heating device work?

The diesel engine is generally equipped with automatic cooling water heating device, so that when the generator set is in the standby state, the diesel engine should be in the hot engine state, so that the generator set can start and work with load within 15s when the mains power is lost.

For the automatic heating device of diesel engine, when the water temperature is lower than 30 ℃, the contact of temperature controller is connected, KM is pulled in, and the heater eh works. When the water temperature rises to 50 ℃, the contact of the thermostat is disconnected, KM is released, and the heater EH is powered off.

In addition to the cooling water heating device, there are oil heating device and battery heater.

37. How to observe the power of maintenance free battery with eyes?

There is usually a transparent observation port above the battery. When we look down from the top, we can see the color inside. If it is green, it indicates that the battery is fully charged; if it is white, it indicates that it needs to be charged; if it is black, it indicates that it needs to be replaced.

38. What's the matter with white solid on the battery terminal?

This is a normal phenomenon. The white solid is the product of the oxidation of battery terminals and air. It will disappear when washed with boiling water during cleaning.