Diesel Generator Repair and Maintenance

- Sep 27, 2018-

    In recent years, with the continuous development of economy and the acceleration of urbanization, people's demand for electricity has been increasing. In this case, the power system will be overloaded, resulting in various power supply problems, which will not only affect People's Daily life, but also affect people's production. In order to guarantee that People's Daily production and life will not be affected in the case of power failure, enterprises need to prepare reserve power supply. Diesel generator sets play a very important role in the common reserve power supply.


    This paper discusses the fault repair and maintenance of diesel generator. Diesel generators are widely used in power backup power supply due to their high thermal efficiency, low fuel consumption, quick start-up, reliable operation and durability in the actual operation. Diesel generator set, however, under the high load operation, also can produce a lot of failure, the failure makes diesel generating sets the efficiency drop, serious when still can interrupt work, therefore, requires relevant maintenance personnel to strengthen the maintenance and diagnosis of diesel engine fault, and strengthen the daily maintenance work, to guarantee the normal work of the diesel engine unit.

1、Basic principle of diesel generator set

    The diesel generator set drives the motor to work through the diesel engine to output electricity. In the actual operation process, the diesel engine rotates to drive the rotor of the generator, and utilizes the principle of electromagnetism induction to make the generator generate the corresponding electromotive force, which then generates the current through the closed loop, and then completes the generation operation.

2、Analysis of diesel generator structure

Generally, diesel generating set is mainly composed of diesel engine, generator and control system, among which, diesel engine and generator are installed on the common base frame after being connected, and then sensors and control system are installed to realize the overall assembly of the whole unit. The sensor is mainly used to detect the operating parameters of the unit, and the control system is mainly used to protect the unit and display various electrical parameters to the operators. In addition, the diesel generator set has chassis, coupling, radiator, fuel tank, muffler, housing, shock absorber or rubber cushion.

3、 analysis of common failures and solutions

3.1 common fault analysis of generator set startup part

    One of the common faults of generator sets is the fault of starting part, which is mainly divided into two types:

    The first kind is manual startup fault, which is mainly manifested in the damage of manual drawstring, including breaking of the drawstring, no movement of the drawstring and damage of the drawstring tray .During the process of troubleshooting this part, the maintenance personnel shall first check the drawstring and then carry out specific maintenance according to the fault cause. The second is the fault of the electric starting part, which is more complicated than the fault of the manual part. The battery can directly affect the start state of magnetic switch. Once the battery has insufficient voltage, it will directly affect the normal start of generator set. Second, the magnetic switch problem. The closure of magnetic switch is carried out under the condition of electrification, and the battery is the key to electrification. Once the battery voltage is not sufficient enough, it will cause problems in the magnetic switch absorbing, which may lead to serious damage of magnetic switch. Finally, there is a problem with the solenoid fuel valve, which will cause abnormal voltage.

3.2 insufficient output power of generating set

    There are many reasons for the under output power of generating sets. The main reasons are: first, the unit power exceeds the rated power. If the generator set is in a state of overload, then the instruments on the control system will make a certain response. The number of the voltmeter and ammeter is beyond the rated range. Second, the fuel temperature is too high. The temperature of the fuel oil directly affects the torque output power of diesel engine, under normal circumstances, the oil temperature of the diesel generator set shall not exceed 70 ℃ , once more than the defined value, can reduce heat capacity, thus appeared the phenomenon of the output power is insufficient, affect the normal operation of the fuel system. Therefore, operators must control the fuel temperature.

4、Analysis of diesel generator operation and maintenance

4.1 diesel generator equipment storage and maintenance

    The most taboo of any mechanical equipment idle, this is because mechanical equipment in the idle process is easy to rust, and fast loss. Therefore, the maintenance department needs to strengthen the effective storage of diesel generating sets, and ensure the dry storage space and less dust, so as to greatly reduce the impact of dust and moisture on diesel generating sets. In addition, there is a need to strengthen the storage and management of diesel. Diesel, as an important energy source for generating sets, will affect the performance of combustion performance once it contains impurities, so it must be ensured that it will not be polluted by other substances.

4.2 regular maintenance

    Relevant departments shall carry out regular maintenance and maintenance of diesel generating sets in accordance with certain maintenance manuals, timely replacement of damaged parts and repair of parts that need to be repaired in accordance with relevant regulations, so as to ensure the best condition of diesel generating sets. When maintaining the lubricating system of the diesel engine, the specific contents are as follows: first, there is no need to replace the oil. Second, when changing oil, the operating environment should be as clean as possible, do not operate in dusty weather and environment. Third, cold area of oil change cycle reduced, at least three months in a year the temperature below - 20 ℃, the oil change cycle to shorten appropriately. Fourthly, under normal circumstances, the oil level should be inspected once a day for the grinding period and once a week after the end of the grinding period. Fifth, new oil filter element must be installed every time the oil is replaced. Sixth, when replacing the oil, the waste oil should be collected by special containers, and should not be poured into the sewer to avoid environmental pollution.

5、Troubleshooting of diesel generator set

5.1 fault diagnosis and analysis

    Related maintenance personnel need to accurately judge and analyze the faults of diesel generator set. This is because the preliminary analysis and judgment directly affect the maintenance effect of generator sets and the selection of maintenance methods in the later stage. Therefore, maintenance personnel must ensure the accuracy of diagnosis results.

5.2 comparison of fault types

    In a sense, the fault type directly affects the maintenance work.Therefore, relevant departments need to classify and summarize the faults of diesel generator sets, and edit them into a book, so as to help maintenance personnel to make fault diagnosis and maintenance quickly.

5.3 qualitative treatment of failures

    The maintenance department needs to deal with the faults of diesel generator set qualitatively, so as to ensure that no errors and errors occur in the maintenance work.Therefore, maintenance personnel are required to take seriously the fault maintenance work in the actual working process with a realistic and rigorous attitude, and carry out fault elimination and maintenance according to the type of fault, so as to improve work efficiency and maintenance quality.

5.4 case analysis

First, fault phenomenon: the phenomenon of "jet oil" appeared in the actual operation of the diesel engine. After the relevant personnel have finished the preparation work of cleaning the cylinder block of oil pan, they have conducted sectionalized experiments to check the specific oil leakage location. The lower exhaust is not large, and the exhaust pipe smoke color is normal; No abnormal valve cover. Second, the cause of the problem analysis: during the running period of diesel engine piston ring gas channeling phenomenon to a certain extent, and the oil and gas separator will crankcase oil and gas separation, and the gas suction chamber combustion after separation, if appear jams phenomenon of oil and gas separator, the pressure in the crankcase is too high, oil sump oil through pipeline, oil into the oil and gas separator, from the outlet. Third, solution: the operator needs to check the hydraulic components, hydraulic pipes and front-end operating devices of the diesel engine regularly by referring to the equipment operator manual. If the machine operates for a long time, such as 24 hours a day, it needs to check more frequently. Before the inspection, the inspection point should be cleaned to remove impurities such as hydraulic components and dirt on the pipeline. Once check oil pipelines or Ο ring failure, the operator needs to contact the dealer service personnel for order a replacement as soon as possible.

6 the conclusion

To sum up, diesel generator is an important power system equipment, whose safe, stable and efficient operation is the focus of people's attention.Therefore, relevant maintenance personnel should strengthen their fault research and maintenance measures analysis, and pay attention to their maintenance, so as to promote the safe, stable and efficient operation of diesel generating sets.