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What problems should be paid attention to in the maintenance of different parts of the diesel generator set?

June 09, 2022
After the diesel generator set has been used for a period of time, it must be maintained. Only irregular maintenance of the diesel generator set can ensure that the power of the diesel generator set will not be reduced. For the maintenance of different parts, users should pay attention to the following issues :
For maintenance personnel, it should be ensured that the fuel quality, the oil that meets the requirements of the label has a reasonable viscosity, is clean and free of impurities, and is filtered and deposited. Its main performance indicators are cetane number, viscosity, freezing point, ash and impurities, actual gum and so on. Improper fuel label selection (condensation point deviation) can cause temporary blockages, including filters, fuel pumps, and fuel supply systems. High levels of carbon residue, ash, actual colloids, moisture, moisture, and other particulates can shorten fuel supply system filter replacement intervals and prevent the filters in the fuel supply system from functioning properly. Under no load or light load, the frequency of the unit drops sharply under light or heavy load, which is the most typical phenomenon. In this regard, if the filter element is not replaced for a long time, it will also cause blockage and premature wear of the high-pressure oil supply circuit and the injector, which will greatly shorten the life of the unit and increase the difficulty of solving the fault. This time must be excluded by professionals. Therefore, under normal circumstances, the fuel supplied by the unit must be precipitated and filtered to ensure that the fuel is clean.
Maintenance of lubrication system
We all know the lubrication of the unit, the lubrication system of the unit is very important, otherwise it will not only affect the normal operation of the unit, but also cause serious damage to the unit components, or even scrap. Generally speaking, the lubrication system has five functions:
(1) The friction surfaces of the parts are separated by a lubricating film to reduce wear and power consumption.
(2) The flowing lubricant takes away the heat generated by the friction surface and cools the surface of the friction point.
(3) The flowing lubricant cleans the friction surface, takes away the worn metal chips and dirt, and reduces the wear of components.
(4) Lubricating oil should be added between the cylinder liner, the piston and the piston ring to help seal and facilitate sealing and starting.
(5) Apply a layer of lubricating oil on the surface of machine parts to prevent surface oxidation and corrosion. Therefore, in addition to the selection of high-quality lubricating oil, its main performance indicators include: viscosity, kinematic viscosity ratio, freezing point, flash point, acid value, etc. The maintenance of the lubrication system should be completed regularly according to regulations. The details mainly include: oil level inspection, oil pressure inspection and adjustment, oil temperature (82-107 degrees) inspection, replacement of filter element, cleaning filter, sealing oil pump, etc.
Maintenance of equipment cooling system (water cooling)
It is very important for the cooling system of the unit to work properly, because the cooling system is ineffective or not cooling will lead to the following consequences:
The strength and stiffness of the metal material decrease significantly as the component overheats. The high heating temperature of the components causes the volume expansion, so that the parts cannot cooperate normally, or even get stuck and damaged. If the temperature is too high, the viscosity of the lubricating oil will decrease, and even oxidative coking will occur, and the lubricating effect will be lost. If the temperature of the components in the cylinder is too high, the fresh air entering the cylinder will be heated by the high-temperature components, increasing the specific volume and reducing the actual intake air volume. Too low cooling system temperature will lead to the following consequences: the viscosity of the lubricating oil increases, the fluidity becomes poor, and the frictional resistance of the moving parts increases. The temperature of the in-cylinder components is too low, prolonging the fuel ignition delay time and making the work rough. The heat loss taken away by the cold increases and the effective power decreases.
It is not difficult to see from this that whether the cooling system can work normally or not directly affects the power, economy, reliability and service life of the internal combustion engine. Therefore, be sure to carefully maintain:
(1) Check the cooling water level and water quality.
(2) Regularly clean the cooling system.
(3) Check and adjust the tension of the fan belt.
(4) Check the thermostat (74-91 degrees).
(5) Take effective measures to prevent the unit from freezing in the cold season. If necessary, the water in the cooling system must be completely drained.
Machine room ventilation system maintenance:
Although the ventilation of the machine room does not belong to the unit itself, it is the basic prerequisite for the normal operation of the unit. If the ventilation of the machine room is poor, it will seriously affect the power, economy, reliability and service life of the unit. The most intuitive and common phenomenon is:
(1) Reduce the replacement cycle of air filters, oil filters and fuel filters, and accelerate the wear of mechanical parts.
(2) Since the unit cannot get enough fresh air, the power (load capacity) of its prime mover is severely limited. The cooling of the unit cannot be guaranteed, resulting in overheating of the generator and prime mover, the entire system being interrupted due to protection, or even the generator being burned out.
Maintenance of controls and other ancillary systems
Although the control and other auxiliary systems are not the main body of the unit, they must complete the intelligent control, automatic protection, data detection and transmission, interlock control of the transfer switch, and start-up battery charging. Equipment preheating is critical to the normal and safe operation of the entire system. Therefore, its regular maintenance is very necessary, mainly including:
(1) Whether the automatic start, stop and ATS chain control functions are normal.
(2) Simulation test of unit protection function (high water temperature, low oil pressure, overspeed).
(3) Whether the preheating of the charger and unit is normal.
(4) Whether the sampling and display of unit parameters are normal.