Common faults and treatment methods of diesel generators
The use of diesel generators in the industry is very important. After a long period of use, diesel generators may have a lot of faults, so how should we deal with these faults? Let ’s learn about them
1. What is the problem of generator (electric ball) demagnetization and what should I do?
Answer: The generator (electric ball) is not used for a long time, which causes the residual magnetism contained in the iron core to be lost before leaving the factory. The excitation coil cannot establish the proper magnetic field. At this time, the engine is running normally but cannot generate electricity. More units or long-term unused units. Approach:
1) Press the excitation button with the excitation button.
2) If there is no excitation button, use a battery to magnetize it.
3) With a light bulb load, run at high speed for a few seconds.
2. What level of energy does electric energy belong to? What are the characteristics of alternating current?
Answer: Electrical energy is a secondary energy source. AC power is converted from mechanical energy and DC power is converted from chemical energy. The characteristic of AC power is that it cannot be stored.
3.Why must the generator (electric ball) working warehouse be clean and the ground free of dust?
Answer: If the diesel engine sucks dirty air, it will reduce its power; if the generator sucks sand, dust and other impurities, it will destroy the insulation between the stator and rotor gap, and in serious cases, it will burn.
4. What are the reasons for causing high water temperature alarm shutdown and even unavailability?
Answer: 1) The water tank is leaking or the amount of water is insufficient;
2) The water temperature sensor is damaged;
3) The dirt in the water tank is too thick or the fins are too oily;
4) The fan belt is too worn and the pressure is insufficient;
5) The pump is worn and the amount of pump water is insufficient;
6) The opening angle of the thermostat is not enough, and there is a stuck phenomenon;
7) Cylinder gasket is broken, and the water channel communicates with the cylinder;
8) Cylinder liner wears too much and seeps locally;
9) The ventilation of the equipment room does not meet the requirements;
10) The engine is overloaded.
5.Why does the diesel engine emit black smoke?
Answer: When the diesel engine is under high load, the exhaust gas is liable to emit black smoke. The generation process of black smoke is not completely clear at present. It is generally believed that when the load of the diesel engine is high, the fuel injected into the combustion chamber increases, the temperature in the combustion chamber is high, and the characteristics of the diesel mixture are not uniform. It will cause the combustion of insufficient air in the local area of the combustion chamber, the fuel will decompose under the condition of high temperature and oxygen, and polymerize to form soot (carbon black). Soot is not pure carbon, but a polymer. The main component is carbon (85% or more), but it also contains a small amount of oxygen, hydrogen and ash, and its composition changes with the load of the diesel engine. The soot is collected through a filter, and the soot is collected and observed under an electron microscope. It can be seen that the large soot particles are about 0.05 μm in diameter. High-temperature cracking reactions in diesel engines are inevitable, especially in space-blended diesel engines, where high-temperature gas surrounds liquid oil droplets, resulting in the most favorable conditions for cracking reactions. High-speed photography of the combustion process confirms that A large amount of black smoke will appear near the top dead center, but in general, the soot can completely find the air in the subsequent combustion, so that the exhaust is free of black smoke. However, if the air in the cylinder is insufficient and the mixing process is slow, then the cylinder temperature will decrease due to expansion, and the carbon will not burn and be polymerized into soot. The formation of soot causes incomplete combustion, the diesel economy is reduced, the exhaust temperature rises, the exhaust emits black smoke, and the surface area of the combustion chamber is carbon, and the load can no longer be increased. Carbon deposits can also cause piston ring or piston jams and valve seizures. Therefore, the diesel engine is not allowed to work under a long-term overload condition.
5. Why is there water in the fuel tank and how to prevent it?
Answer: Qualified fuel oil does not contain impurities and moisture when it leaves the factory, but it will more or less be mixed with dust, dirt and moisture during transportation and storage; when the fuel tank is not full, moisture in the air in the tank will easily form condensed water droplets and mix into the fuel. . Pay attention to the following points in the use and storage of fuel:
1) Fuel must be stored in the fuel tank for more than 24 hours to allow water and impurities to settle before use;
2) Fill the daily fuel tank as much as possible after each work, so that the water in the fuel tank air can be prevented from mixing into the fuel;
3) When filling the oil, first wipe the funnel and the fuel tank end cap. When using the hand pump, be careful not to pull out the lower sediments together;
4) Open the fuel tank drain cock regularly to remove water and sediment.
6.What faults can cause the gearing of the motor (electric ball) group to start the gear?
Answer: The battery power is insufficient. The battery temperature is too high; the starter motor relay does not work; the starter motor transmission gear and the flywheel ring gear cannot mesh; the starter motor enters the meshing and the diesel engine cannot rotate or is weak; The starting motor cannot be separated;
7.What are the main reasons for AVR damage?
Answer: AVR circuit consists of three parts: rectifier main circuit, voltage detection circuit and comparison control circuit. Excluding the possibility of damage caused by the original quality of the original electrical components, in the whole AVR circuit, the main circuit and the comparison The operating frequency of the control circuit changes the most. Among them, the rectifier bridge in the main circuit and the transistor in the comparison circuit change more frequently, and the damage ratio accounts for more than 90% of the damage rate of the entire AVR. In view of the fact that AVRs on imported generators are non-repairable parts, If it is damaged, it must be replaced with a new one. Therefore, we mainly analyze the causes of AVR damage on the generator. It is most important to avoid AVR damage as much as possible. As long as it is used properly, it can increase the life of the AVR. The more stable the generator voltage, the smaller the fluctuation frequency in the AVR; the smaller the switching action of the transistor in the comparison circuit, the smaller the probability of damage to the AVR; the output load is relatively stable, the smaller the fluctuation frequency in the AVR, the smaller the transistor in the comparison circuit The smaller the switching action, the smaller the chance of AVR damage; the more stable the speed of the diesel engine, the smaller the shock of the changing current to the AVR; the frequent "parking car" and overload, the difference between the three-phase load is too large to cause AVR damage The most important reason is to choose generator sets with E, F, and C fuel systems. Due to the small frequency variation, the use of AVR will be more reliable.
8. What are the conditions for the two generators to be paralleled and what devices are used to complete the parallel work?
Answer: The conditions for parallel use are that the instantaneous voltage, frequency and phase of the two machines are the same. Commonly known as "three simultaneous". Use a special parallel device to complete the parallel work. It is generally recommended to use a fully automatic cabinet. Try not to use manual parallel. Because the success or failure of manual parallelism depends on human experience. With more than 20 years of experience in electrical work, the author ventures to say that the reliable success rate of manual parallel operation of diesel generators is equal to zero. Never use the concept of manual parallel operation of a large power system for a commercial power system to apply a small power system, because the protection levels of the two are completely different.
The above is the content of common faults and solutions for diesel generators shared by diesel generator customer service, and I hope to help everyone. If you have more content about diesel generators, please contact us in time.