Daily Maintenance Of Diesel Generators

  • 30 - 12 - 2019
  • 199

A diesel generator is an independent power generation device that provides emergency power in the event of a power outage. In fact, most of the time, the unit is in the standby state, and the chances of actually putting it into use are relatively small. Usually, it is mostly based on test machines, and it lacks perfect detection and maintenance methods. But such emergency backup power is indispensable. How to ensure that the generator can supply power in a timely manner in an emergency when the generator is used less often, and the operation is safe and reliable. After the power failure, the generator can be stopped immediately. In this article, Jiangsu Fusong introduces some simple methods that can effectively achieve the purpose.


First, check the battery pack. As the backup power is not often put into use, whether the generator can start normally depends on the maintenance of the battery. If there is a problem with the battery pack, the more common situation is that there is voltage and no current. At this time, the sound of the solenoid valve in the starter motor can be heard, but the shaft cannot be moved.

There are three reasons for the battery pack to fail to stop:

1. Stopping the battery during testing will cause the battery to run low.

2. The mechanical oil pump is driven by a belt, and the amount of pump oil at the rated speed is large. However, the battery pack is insufficient in power supply, which causes the spring leaf in the shut-off valve to stop from the four oil outlets due to insufficient solenoid valve suction during shutdown. Fuel cannot be stopped.

3. Domestic batteries usually have a life of two years and are not replaced regularly.

Second, start the inspection of the solenoid valve. When the generator was running, people summed up a set of inspection methods of “one look, two listens, three touches, four smells”. Listening at startup is an important step. Take the original American Cummins generator as an example, just press the start button, and it will start after three seconds. Two “clicks” can be heard within these three seconds. Once the second sound is not heard, it is necessary to check whether the start solenoid valve is working normally. Of course, if the solenoid coil is blown, the generator cannot start of course.

Third, the inspection of diesel and lubricating oil. Because the unit is in a static state for a long period of time, various materials of the unit itself will undergo complex chemical and physical changes with engine oil, cooling water, diesel, air, etc., and the unit will be “dead”. For this reason, attention should be paid to the problem of oil. For fire safety, the diesel fuel tank is usually placed in a closed room. Due to the condensation of water vapor in the atmosphere due to temperature changes, water droplets are attached to the inner wall of the fuel tank and flow into the diesel, causing the diesel water content to exceed the standard. If such diesel enters the high-pressure oil pump of the diesel engine, it will rust the precision coupling, the plunger, and seriously damage the unit. Generator lubricating oil has a shelf life. When stored for a long time, the physical and chemical properties of the lubricating oil will change, which will cause the lubrication state of the unit to deteriorate during work and easily cause damage to the generator parts.

Maintenance points:

First, relevant electrical regulations and national standards stipulate that first-class high-rise buildings should be powered according to the first-level load, and emergency diesel generator sets must be used. The primary load power supply is generally: TV stations, radio stations, civil airports, railway stations, banks, hospitals at or above the county (district) level, meteorological stations at or above the city (region) level, important office buildings, colleges and universities, and important laboratories of the Academy , Large museums, and computing centers.

Second, the motor must be protected by dual-circuit power, and the mains oil generator can be automatically switched. Each year, the load test is performed according to the regulations, and a fake load can also be used;

The precautions for routine maintenance are as follows:

1. Read the instructions carefully

Read the instruction manual carefully before use. Select and replace the engine oil in strict accordance with the instructions. Different domestic and foreign engine oils must not be mixed. During use, the oil level should be checked frequently to keep the oil in the normal range.

2. Items to check before the machine runs

(1) Check the appearance. Whether the engine is damaged or missing, and whether the screws are loose.

(2) Check the fuel system. Whether the amount of fuel is sufficient, whether the wiring piping is leaking or that the fittings are loose, and the air in the fuel system is excluded.

(3) Check the lubrication system. Whether the engine oil is sufficient. After the new engine or reinstalled engine is running for 50 hours, it must perform various maintenance, such as replacing the engine oil, lubricating oil filter, diesel filter, and checking and adjusting the valve clearance. Check the bolts on the outside of the engine.

(4) Check the circuit. Check the generator output and control lines for damage and looseness. Do not start with load. The power must be cut off when shutting down.

(5) Check the cooling system. If the amount of water for cooling the radiator is sufficient, add rust inhibitor.

3. Matters needing attention during operation

(1) Pay attention to the “six tables” during operation. AC ammeter: The needle indicates whether it is normal. Measure the current value of each phase. The current difference between any two phases should not be too large. AC voltmeter: whether the voltage indicated by the needle is normal. Whether the water temperature is within the normal range (65 ~ 93 ℃); oil pressure gauge: whether the indicated oil pressure is within the normal range; charging gauge: whether the pointer is in the direction of “+”.

(2) Listen carefully. When you hear abnormal sounds or vibrations from the generator engine, remove them in time.

4. Can not ignore the “three filters”

The “three filters” on diesel generators are very important in the use of diesel engines. To extend the service life of diesel generators, it is necessary to strengthen the maintenance of air filters, oil filters and fuel filters during use. Play its part. The air filter should be dusted once every 50 to 100 hours of operation. If the working time exceeds 500 hours or is damaged, it should be replaced. Use oil-bath air filter, every 100-200 hours, clean the filter element with clean diesel and replace the oil in it. If the filter element is broken, it needs to be replaced immediately. The oil filter should be cleaned once every 180 to 200 hours of operation. If it is found to be damaged, it should be replaced immediately. The fuel filter should be cleaned once every 100 to 200 hours of work, and the fuel tank and each oil pipeline should be thoroughly cleaned. During seasonal oil changes, all parts of the entire fuel supply system should be cleaned.

5. Use and maintenance of batteries

Always check whether the battery’s electrolyte is on the normal level. When rehydration is needed, the filling port should be cleaned first to prevent dirt from falling into the battery. When adding liquid, the amount of distilled or purified water should be added. Do not overfill (according to the scale of the battery plate), otherwise, the internal electrolyte will overflow from the filling port when the battery is discharged / charged. Corrosion to surrounding objects. Always check whether the voltage is correct, whether the connector is loose, and whether the charger is operating normally. The start time of the generator is less than or equal to 10s, and the restart time should be more than 2min. This is to protect the starter motor and battery. When starting a diesel engine, the starting current of the starter is 300 ~ 400A. If the starting time is too long or the start is continuous, it will cause the coil of the electric starter to heat up, resulting in burnout or damage to the battery.

6. Avoid overloading

7. The starting electrical equipment is turned on in order from large to small. The main purpose is to prevent the generator from overloading.

8. Ensure that small electrical appliances and various meters work properly. Always check the small electrical appliances and various meters and meters in generators and diesel engines to avoid operating errors caused by signal failures and damage to the generator.

9. Regularly clean the generator. Disconnect all power sources when cleaning. In addition to external dust, dirt, and oil stains, the ventilation net must also be cleaned, because these things enter the coil, which will overheat the coil or damage the insulation. Dust and dirt are quite good to be removed with a vacuum cleaner. Do not use air blow or high pressure water spray to clean it. If the insulation resistance decreases due to the dampening of the generator, the generator must be dried.

10. The machine room must be specially supervised by the person in the generator room. The ventilation in the generator room must be good, and no casual personnel are allowed to enter the machine room. When working, it must be supervised by personnel.


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