Questions about diesel generator

Questions about Diesel Generator – In this article, let’s talk about diesel generator sets and their frequently-asked-questions. This article probably will save your day and even your diesel gen-set. Are you ready? Let’s go with the questions and answers.

1. Different climatic environments impacts for diesel generator operation:

  • Rainwater
  • Dust and sand
  • Saltwater and fog at the seaside
  • Corrosive gases in the air, such as sulfur dioxide

2. The composition of the diesel generator set:

Diesel engine, generator, controller. Other components: base, base fuel tank, radiator, water tank, recoil pad, anti-speaker, silencer, silent speaker, and other components.

3. How long does the diesel generator set three filter replacements?

Air filter: 1000 hours, can be more different environments to shorten the replacement cycle.

Diesel filter: the first work is 50 hours to replace after the general is 400 hours to replace. If the user uses diesel fuel which quality is not good, shorten the replacement cycle.

Oil filter: 50 hours to replace the first work, after the general is 200 hours to replace.

4. How to identify the authenticity of the engine?

Appearance: For professionals who are familiar with the engine, you can identify the authenticity of the engine by the appearance of the engine, color, overall color difference.

Marking distinguish: diesel engines have the corresponding brand logo sticker on the body.

Nameplate to distinguish: the engine has a nameplate marked with the engine number, cylinder block, oil pump, and also has the corresponding code, call the original factory to confirm the code, so you can know the authenticity of the engine.

5. Motor protection grade IP Introduction:

‘I’ represents the level of protection against the ingress of solid foreign bodies, the highest level being 6.

‘P’ stands for protection against the ingress of water, the highest level being 8.

For example, protection class IP56, IP55, etc. (D.NJ Power generators have IP56 protection class)

6. Introduction of motor insulation level:

The insulation level of the motor is divided according to the heat resistance level of the insulation material used, which is generally divided into 5 levels.

Grade A 105 degrees

Grade E 120 degrees

Grade B 130 degrees

Class F 155 degrees

H class 180 degrees

D.N Power generators have a theater rating of H.

7. Noise level introduction:

30 to 40 decibels is a more ideal quiet environment. More than 50 decibels will affect sleep and rest. 70 decibels or more will interfere with conversation and affect work efficiency. Long-term living in a noise environment of more than 90 decibels will seriously affect hearing and cause neurasthenia, headaches, increased blood pressure and other diseases. If suddenly exposed to a noisy environment of up to 150 decibels, acute trauma to the auditory organs can occur causing the eardrum to rupture and bleed and both ears to lose their hearing completely. In order to protect hearing, noise should be controlled at no more than 90 decibels; in order to ensure work and study, noise should be controlled at no more than 70 decibels in order to ensure rest and sleep, noise should be controlled at no more than 50 decibels.

8. The purpose of parallel operation of diesel generator sets:

Expansion of power supply capacity

Improve the reliability of power supply and realize uninterrupted power supply.

9. The role of ATS:

ATS is the switching switch between utility power and power generation power two sets of switching contacts, one for power generation and one for mains power. Automatic switching is possible through controller commands.

10. Fuel consumption calculation:

Fuel consumption (L/h) = rated power of diesel engine (kw) X fuel consumption rate (g/kwh) / 1000 / 0.84

(The density of diesel 0# is taken as 0.84kg/L)

11. Diesel generator set commissioning steps:

Diesel engine inspection — generator inspection — no-load commissioning — commissioning with load — filling out commissioning report — -Cleaning up the site

12. Generator sets can be divided into several categories in terms of energy:

Nuclear, hydro, wind, and fire. Among them, thermal power is further divided into coal, diesel, gasoline, gas and biogas. The generators we are now dealing with are mainly diesel generators. Diesel is divided into light diesel (0# diesel, commonly used in high-speed diesel engines) and heavy oil (120#, 180# diesel, commonly used in medium-speed diesel engines and low-speed diesel engines).

13. The main functions of the control system:

  • With manual, automatic, test stop
  • With various safety protection functions
  • Memory for various faults in operation
  • LED fault display alarm
  • Display of voltage, current, frequency, etc.
  • Can be connected to a PC, but requires a controller with RS232, 485 ports

14. What happens when a diesel generator set is overloaded for a long time?

The unit cannot normally be overloaded during operation, but it can withstand short-term overloads. If the unit is overloaded for too long, some conditions may occur when the power is over-rated, includes Cooling system overheating, Generator winding overheating, Low oil pressure due to decomposition of lubricant concentration, and Reduced unit life

15. What will happen if the unit load is too low?

If the unit is in low load operation for a long time, which causes the water temperature to rise less than normal, the viscosity of the oil is high and the friction becomes large. The oil in the cylinder that should be burning because of heating causes the formation of varnish on the cylinder gasket. If the low load continues, blue smoke can appear, the surface varnish of the cylinder gasket needs to be removed, or the cylinder gasket needs to be replaced.

16. What do I need to pay attention to when installing the exhaust system?

Generator sets have standard features such as industrial mufflers, flexible exhaust connections, and elbows. The user can install the exhaust system with the provided the exhaust system can be installed with the provided supporting facilities. However, the following points need to be noted during installation.

  1. make sure that the back pressure is lower than the set maximum (usually, don’t be below 5Kpa)
  2. fix the exhaust system to avoid lateral and vertical pressure.
  3. leave room for contraction and expansion
  4. leave room for vibration
  5. reduce exhaust noise

17. When the diesel engine temperature is too high, is it feasible to add cooling water immediately?

Absolutely not, wait until the engine is naturally cooled to room temperature before adding cooling water. If in the diesel engine water shortage overheating in the case of diesel engine water shortage and overheating, it will make the cylinder head, cylinder liner, cylinder block, etc. due to hot and cold and intense changes and cracks, causing serious damage to the engine. The engine will cause serious damage.

18. ATS self-switching operation steps.

  1. The manual operation mode of the module: After turning on the power key, press the “manual” key of the module to start directly. when the unit starts successfully and runs normally, at the same time, the automation module will also enter the self-test state, and it will automatically enter the speed-up state. after the speed-up is successful, the unit will enter the automatic closing and grid connection according to the display of the module.
  2. Full-automatic operation mode: Set the module in “automatic” position and the unit enters the quasi-starting state. In the automatic state, it automatically detects and discriminates the utility state for a long time through the external switch signal. Once the utility power is faulty or lost, it will enter the automatic start state immediately. When the utility power comes in, it will automatically switch the switch to lower the speed and stop. When the utility power is restored to normal, the unit will automatically trip off the grid with a 3-minute delay and automatically shut down when the system 3S confirms, and will automatically enter the next automatic start preparation state.

19. Diesel generator set cylinder sealing becomes a low bad start. How is it?

Cold start engine, especially in winter, because the piston ring and cylinder wall oil are very little, the sealing effect is poor, there will be repeatedly started and cannot fire running phenomenon. Diesel generator sets sometimes, due to cylinder wear heavy and seriously affect the sealing performance of the cylinder, making it more difficult to start. In this regard, the injector can be removed and 30 to 40ml of oil added to each cylinder to enhance the sealing performance of the cylinder and improve the pressure of compression.

20. Diesel generators since the protection function.

Diesel engines and alternators are installed with various sensors, such as water temperature sensors, oil pressure sensors, etc. Through these sensors, intuitive bar diesel engine operating status display to the operator, and with these sensors, you can set a limit, when the limit is reached or exceeded when the control system will pre-alarm, this time if the operator does not take measures, the control system will the diesel generator sets are self-protective in this way. The sensor plays the role of receiving and feeding back various information, the real display of these data and the implementation of the protection function is the control system of the diesel generator set.

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

Air intake noise, exhaust noise, and cooling fan noise

Combustion chamber work combustion noise, mechanical noise of engine parts friction

Noise generated by the rotor rotating at high speed in the electromagnetic field

22. Winter diesel generator set starting skills.

Preheating: The cooling system can be heated with water and the oil sump with a heat source.

Improve the airtightness: you can remove the injector and add 30-40ml of oil to each cylinder to enhance the sealing performance of the cylinder and improve the pressure during compression.

Coiling: Crank the crankshaft before starting to make it run easily before starting.

23. What is the role of the diesel generator piston ring?

  • Heat transfer
  • Control oil
  • Support role
  • Maintain airtightness

24. How many ways and in what order are there to break in a new machine?

First cold break-in, manual rotation, or external force to drive the crankshaft rotation.

Post hot break-in, no-load break-in.

25. The cause of oil deterioration?

  • Use the wrong grade of engine oil, the quality is not up to standard engine oil.
  • The operating condition of the unit is not good, the air and oil are fugitive, the fit-gap is too large, the oil temperature is too high, etc.
  • The unit is often operated at low temperatures.
  • The exhaust gas enters the oil sump and condenses into moisture and acid.
  • The oil filter is too dirty, the filter is leaking inside, and the oil is not filtered through the filter.

26. The role of the oil pump?

The role of the oil pump is to give the lubrication system sufficient pressure oil, so that each mutual movement of the parts to get effective lubrication, the current diesel engines are widely used gear type and rotor type oil pump.

27. What is the role of the governor?

The governor should be able to adjust the oil supply sensitively according to the change of external load to keep the speed stable. It must have two basic parts: sensing element and actuator.

28. The function of automatic voltage stabilizer?

The automatic voltage regulator (AVR) allows the generator to closely maintain a stable voltage from no load to full load. This AVR has a voltage frequency (Hz) proportional characteristic that correctly adjusts to 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. The maintenance of the battery?

For frequent use of the machine, the battery is generally not a problem, as long as the policy of good maintenance, if the battery is not used for a long time, it is necessary to regularly check its power and charge it every 12 weeks (8 weeks in the tropics).

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

Fuel level too low, water temperature too high, water level too low, overload, start failure and signal accordingly.

31. Under what circumstances is the emergency shutdown of the unit?

Over speed, short circuit, phase loss, over-voltage, loss of voltage, low frequency

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

Low oil pressure, high water temperature, low water level, overload, start failure, Overspeed, short circuit, phase loss, high voltage, loss of voltage, low frequency, low starting battery voltage, high starting battery voltage, low oil level, and the alarm system of the unit has relay contacts.

33. Diesel generator sets of oil filter types?

  • Mechanical separation
  • Centrifugal separation
  • Magnetic adsorption

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

The low position of the piston at the end of compression: related parts wear, deformation, etc.

Combustion chamber volume becomes large: valve seat ring wear, piston top depression, cylinder gasket is too thick, etc.

35. Which does include diesel generator sets of automatic control functions?

  • Automatic heating device
  • Automatic regulation of diesel engine speed
  • Charging system
  • Instrumentation System Self
  • Protection devices
  • Starter System

36. The working principle of the automatic heating device?

On the diesel engine, generally add a cooling water automatic heating device to get the generator set in the standby state. the diesel engine should be in a hot state so that the generator set in the utility power loss within 15s to start the generator set and work with a load.

Diesel engine automatic heating device when the water temperature is lower than 30 degrees Celsius. the thermostat contacts will be turned on, KM will be sucked, and heater EH will work. When the water temperature rises to 50 degrees Celsius, the thermostat contacts will break, KM will release, and the heater EH will be disconnected.

In addition to the cooling water heater, there is also an oil heater and a battery heater.

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

There is usually a transparent observation port above the battery. When we look down from above, we can see the color inside. The green color indicates that the battery power is sufficient, the white color indicates the need for charging, and the black color indicates it needs to be replaced.

38. What is the white solid on the battery terminals?

This is a normal phenomenon. The white solid caused by the oxidation of the battery terminal and air will disappear after being washed with boiling water.


So that’s it! if you still have questions about your and diesel generator set and you cannot find the answer here, you are very welcome to ask us! May these articles help you to save your day and even your diesel gen-set!

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