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  • Technical Questions And Answers About Diesel Generators (5)

    36. How to divide the automation level of diesel generator set? Answer: Manual, self-starting, self-starting plus automatic mains conversion cabinet, long-distance three remote (remote control, remote measurement, remote monitoring.)   37. Why is the outlet voltage standard of the generator 400V instead of 380V? Answer: Because the line after the line has voltage drop loss.   38. Why is it required that the place where diesel generator sets are used must have smooth air? Answer: The output of the diesel engine is directly affected by the amount of air sucked in and the air quality, and the generator must have sufficient air for cooling. Therefore, the use site must have smooth air.   39. Why is it not advisable to use tools to screw the above three devices too tightly when installing the oil filter, diesel filter, and oil-water separator, but only need to rotate it by hand to prevent oil leakage? Answer: If it is tightened too tightly, the sealing ring will thermally expand under the action of the oil bubble and the heating of the body, causing great stress. Cause damage to the filter housing or the separator housing itself. What's more serious is the damage to the body's nut so that it can't be repaired.   40. What are the benefits of a customer who has purchased a self-starter but has not purchased an automatic conversion cabinet? Answer: 1) Once there is a power outage in the city network, the unit will automatically start to speed up the manual power transmission time; 2) If the lighting line is connected to the front end of the air switch, it can also ensure that the lighting of the computer room is not affected by the power outage, so as to facilitate the work of the operator;   41. What conditions can the generator set meet before it can be closed for power transmission? Answer: With water-cooled units, the water temperature reaches 56 degrees Celsius. The air-cooled unit and the body are slightly hot. The voltage frequency is normal when there is no load. The oil pressure is normal. Only then can switch on and transmit power.   42. What is the load sequence after power on? Answer: Bring the load in order from largest to smallest.   43. What is the unloading sequence before shutting down? Answer: The load is unloaded from small to large, and finally shut down.   44. Why can't it be shut down and turned on under load? Answer: The shutdown on load is an emergency shutdown, which has a greater impact on the unit. Starting with load is an illegal operation that will cause damage to the electrical equipment of the power generation equipment.   45. What should I pay attention to when using diesel generators in winter? Answer: 1) Note that the water tank must not freeze. The preventive methods include adding special long-term anti-rust, antifreeze or using electric heating equipment to ensure that the room temperature is above the freezing point. 2) Open flame baking is strictly prohibited. 3) The no-load preheating time must be a little longer before power is supplied.   46. ​​What is the so-called three-phase four-wire system? Answer: There are 4 outgoing wires of the generator set, of which 3 are live wires and 1 is a neutral wire. The voltage between the live wire and the live wire is 380V. 220V between the live wire and the neutral wire.   47. What is the three-phase short circuit? What are the consequences? Answer: There is no load between the live wires, and a direct short circuit is a three-phase short circuit. The consequences are terrible, and serious ones can lead to plane crashes and deaths.   48. What is the so-called reverse power transmission? What are the two serious consequences? Answer: The situation of self-provided generators transmitting power to the city network is called reverse power transmission. There are two serious consequences: a) There is no power failure in the city network, and the power supply of the city network and the self-provided generator power supply generate asynchronous parallel operation, which will destroy the unit. If the self-provided generator has a large capacity, it will also cause shocks to the city network. b) The city network has been out of power and is undergoing maintenance, and its self-provided generator is sending power backwards. It will cause electric shock to the maintenance personnel of the power supply department.   49. Why should the commissioning personnel check whether all the fixing bolts of the unit are in good condition before commissioning? Are all line interfaces intact? Answer: After long-distance transportation of the unit, sometimes it is inevitable that the bolt and line interface will loose or fall.   50. What level of energy does electricity belong to? What are the characteristics of alternating current? Answer: Electricity is a secondary energy source. AC power is converted from mechanical energy, and DC power is converted from chemical energy. The characteristic of AC is that it cannot be stored and is used now.   51. What does the general symbol GF for domestic generator sets mean? Answer: stands for dual meaning: a) Power frequency generator set is suitable for the general power 50HZ generator set in our country. b) Domestic generator set.   52. Must the load carried by the generator maintain a three-phase balance during use? Answer: Yes. The maximum deviation shall not exceed 25%, and phase-loss operation is strictly prohibited.   53. Which four strokes does a four-stroke diesel engine refer to? Answer: Inhale, compress, do work, and exhaust.   54. What is the biggest difference between a diesel engine and a gasoline engine? Answer: 1) The pressure in the cylinder is different. The diesel engine compresses air in the compression stroke stage; The gasoline engine compresses the gasoline and air mixture in the compression stroke stage. 2) Different ignition methods. The diesel engine relies on atomized diesel to spray high-pressure gas spontaneously; Gasoline engines rely on spark plugs for ignition. [View Details]
  • Technical Questions And Answers About Diesel Generators (4)

    26. What points must be paid attention to when using diesel generator set? Answer: 1) The water in the water tank must be sufficient and kept working within the allowable temperature range. 2) The lubricating oil must be in place, but not excessive, and kept working within the allowable pressure range. 3) The frequency is stabilized at about 50HZ, and the voltage is stabilized at about 400V. 4) The three-phase currents are all within the rated range.   27. Which parts of the diesel generator set need to be replaced or cleaned frequently? Answer: Diesel filter, oil filter, air filter. (Individual units also have water filters)   28. What are the main advantages of brushless generators? Answer: (1) Exempt the maintenance of carbon brushes; (2) Anti-radio interference; (3) Reduce the loss of magnetic failure.   29. What is the general insulation grade of domestic generators? Answer: The domestic machine is B-class; the marathon brand machine, the Leroy Somer brand machine and the Stamford brand machine are H-class.   30. What kind of gasoline engine fuel needs to be mixed with gasoline and engine oil? Answer: Two-stroke gasoline engine.   31. Which six systems are included in the basic equipment of a diesel generator set? Answer: (1) Oil lubrication system; (2) Fuel system; (3) Control and protection system; (4) Cooling and heat dissipation system; (5) Exhaust system; (6) Starting system;   32. Why do we try our best to recommend customers to use the engine oil recommended by our company in our sales work? Answer: Engine oil is the blood of the engine. Once the customer uses unqualified engine oil, it will cause serious accidents such as bearing shell seizure, gear toothing, crankshaft deformation and fracture, until the whole machine is scrapped.   33. Why do I need to change the oil and oil filter after using the new machine for a period of time? Answer: During the running-in period of the new machine, it is inevitable that impurities will enter the oil pan, causing physical or chemical changes in the oil and the oil filter.   34. Why do we require customers to incline the exhaust pipe 5-10 degrees downward when installing the unit? Answer: To prevent rainwater from entering the smoke exhaust pipe, leading to major accidents.   35. Generally, diesel engines are equipped with manual oil pumps and exhaust bolts. What are their functions? Answer: It is used to remove the air in the fuel pipe before starting. [View Details]
  • Technical Questions And Answers About Diesel Generators (3)

    16. How to calculate the current of a three-phase generator? Answer: I = P / (√3 Ucos φ) That is, current = power (watts) / (√3 *400(volt) * 0.8). The simplified formula is: I (A) = unit rated power (KW) * 1.8 17. What is the relationship between apparent power, active power, rated power, maximum power, and economic power? Answer: 1) The unit of apparent power is KVA, which is used to express the capacity of transformers and UPS in our country. 2) The active power is 0.8 times the apparent power, the unit is KW. my country is used to power generation equipment and electrical equipment. 3) The rated power of a diesel generator set refers to the power that can be operated continuously for 12 hours. 4) The maximum power is 1.1 times the rated power, but only 1 hour is allowed within 12 hours. 5) The economic power is 0.75 times the rated power, which is the output power that the diesel generator set can run for a long time without time limitation. When running at this power, the fuel is the least and the failure rate is the lowest. 18. Why is it not allowed for diesel generator sets to run for a long time when the power is less than 50% of the rated power. Answer: Increased oil consumption makes diesel engines prone to carbon formation, which increases the failure rate and shortens the overhaul period. 19. The actual output power of the generator during operation is based on the wattmeter or the ammeter? Answer: The ammeter shall prevail, and the power meter is for reference only. 20. The frequency and voltage of a generator set are both unstable. Is the problem with the engine or the generator? Answer: It lies in the engine. 21. The frequency of a generator set is stable, but the voltage is unstable. The problem is the engine or the generator? Answer: It lies in the generator. 22. What is the loss of magnetism of the generator and how to deal with it? Answer: The generator is not used for a long time, causing the remanence contained in the iron core to be lost before leaving the factory, and the excitation coil cannot build the proper magnetic field. At this time, the engine is running normally but no electricity is generated. This kind of phenomenon is a new machine. Or there are more units that have not been used for a long time. Solution: 1) Press the excitation button once if there is an excitation button, 2) if there is no excitation button, use a battery to magnetize it, 3) load a light bulb and run it at overspeed for a few seconds. 23. After the generator set has been used for a period of time, it is found that everything else is normal but the power drops. What is the main reason? Answer: a. The air filter is too dirty and the intake air is not enough. At this time, the air filter must be cleaned or replaced. b. The fuel filter device is too dirty and the fuel injection volume is not enough, so it must be replaced or cleaned. c. The ignition time is not correct and must be adjusted. 24. After a generator set is loaded, its voltage and frequency are stable, but the current is unstable. What is the problem? Answer: The problem is that the customer's load is unstable, and the quality of the generator is absolutely fine. 25. The frequency of a generator set is unstable. What is the main problem? Answer: The main problem lies in the unstable speed of the generator. [View Details]
  • Technical Questions And Answers About Diesel Generators (2)

    6. What problems should be paid attention to when using the unit with ungrounded neutral point? Answer: The 0 line may be charged because the capacitor voltage between the live line and the neutral point cannot be eliminated. The operator must regard the 0 line as a charged body. It cannot be handled according to utility power habits. 7. How to match the power of UPS and diesel generator to ensure stable output of UPS? Answer: 1) UPS is generally expressed in apparent power KVA, first multiply it by 0.8 and convert it to the unit KW which is consistent with the generator's active power. 2) If a general generator is used, the active power of the UPS is multiplied by 2 to determine the power of the generator, that is, the power of the generator is twice the power of the UPS. 3) If a generator with PMG (permanent magnet machine excitation) is used, the UPS power is multiplied by 1.2 to determine the generator power, that is, the generator power is 1.2 times the UPS power. 8. Can electronic or electrical components marked with a withstand voltage of 500V be used in diesel generator control cabinets? Answer: No. Because the 400/230V voltage marked on the diesel generator set is the effective voltage. Its peak voltage is 1.414 times the effective voltage. That is, the peak voltage of the diesel generator is Umax=566/325V. 9. Do all diesel generator sets have self-protection function? Answer: No. At present, there are even some units of the same brand in the market, and some do not. The user must figure it out by himself when purchasing the unit. It is best to write in written materials as an attachment to the contract. Generally, low-cost machines do not have self-protection function. 10. How to identify fake, inferior and counterfeit domestic diesel engines? Answer: First check whether there is a factory certificate and a product certificate. These are the "identity certificates" for the diesel engine to leave the factory and are required. Check the three major numbers on the certificate again: 1) nameplate number; 2) body number (the actual product is usually on the plane machined at the flywheel end, the font is convex); 3) the oil pump nameplate number. Check these three numbers with the actual numbers on the diesel engine, and they must be accurate. If any doubts are found, these three numbers can be reported to the manufacturer for verification. 11. After the operating electrician takes over the diesel generator set, which three points must first be verified? Answer: 1) Verify the real useful power of the unit. Then determine the economic power and reserve power. The method of approving the real useful power of the unit is: the 12-hour rated power of the diesel engine is multiplied by 0.9 to obtain a data (kw). If the rated power of the generator is less than or equal to this data, the rated power of the generator is regarded as the real useful power of the unit. If the rated power of the generator is greater than this data, this data must be used as the real useful power of the unit. 2) Verify which self-protection functions the unit has. 3) Check whether the power wiring of the unit is qualified, whether the protective grounding is reliable, and whether the three-phase load is basically balanced. 12. There is an elevator starting motor of 22KW, what size generator set should it be equipped with? Answer: 22*7=154KW (the elevator is a direct load starting model, and the instantaneous starting current is generally 7 times the rated current to ensure that the elevator moves at a constant speed). (That is, it should be equipped with a generator set of at least 154KW) 13. How to calculate the optimal power (economic power) of the generator set? Answer: P is best = 3/4*P rated (that is, 0.75 times the rated power). 14. According to the national regulations, how much higher the engine power of a general generator set should be than the generator power? Answer: 10℅. 15. The engine power of some generator sets is expressed in horsepower. How to convert horsepower to international unit kilowatts? Answer: 1 horsepower = 0.735 kilowatts, 1 kilowatt = 1.36 horsepower. [View Details]
  • Technical Questions And Answers About Diesel Generators (1)

    1. What are the conditions for the parallel use of two generator sets? What device is used to complete the parallel work? Answer: The condition for parallel use is that the instantaneous voltage, frequency and phase of the two machines are the same. Commonly known as "three simultaneous". Use a dedicated parallel device to complete the parallel work. It is generally recommended to use fully automatic cabinets. Try not to manually parallel. Because the success or failure of manual paralleling depends on human experience. With more than 20 years of experience in electric power work, the author boldly stated that the reliable success rate of manual parallel diesel generators is equal to zero. Never use the concept of manual paralleling for large mains power supply systems to apply small power supply systems, because the protection levels of the two are completely different. 2. What is the power factor of the three phase generator? Can a power compensator be added to improve the power factor? Answer: The power factor is 0.8. No, because the charging and discharging of the capacitor will cause the fluctuation of the small power supply. And the unit oscillates. 3. Why do we require customers to tighten all electrical contact parts every 200 hours of operation? Answer: Diesel generator set is a vibrating working device. Moreover, many domestically produced or assembled units should use double nuts which are useless. The use of spring washers is useless. Once the electrical fasteners are loosened, a large contact resistance will be generated, which will cause the unit to operate abnormally. 4. Why must the generator room be clean and free of floating sand on the ground? Answer: If the diesel engine sucks in dirty air, the power will decrease; if the generator sucks in sand and other impurities, the insulation between the stator and rotor gaps will be damaged, and the worst will cause burnout. 5. Why our company generally does not recommend users to use neutral point grounding during installation? Answer: 1) The self-regulating function of the new generation generator is greatly enhanced; 2) In practice, it is found that the lightning failure rate of the neutral-grounded unit is relatively high. 3) The grounding quality requirements are high, and ordinary users cannot do it. Unsafe working grounding is not as good as ungrounding. 4) Units whose neutral point is grounded will cover up the leakage faults and grounding errors of the load, and these faults and errors cannot be exposed under the condition of large current supply from the mains. [View Details]
  • Diesel Generators

    Diesel generator is a kind of small power generating equipment, which refers to power machinery that uses diesel fuel as fuel and diesel engine as prime mover to drive generator to generate electricity. The complete set is generally composed of diesel engine, generator, control box, fuel tank, storage battery for starting and control, protection device, emergency cabinet and other components. It can be used for daily power generation and emergency power generation in various homes, offices, large, medium and small enterprises. [View Details]
  • “Racing” Problem of Diesel Engine

    During the operation of diesel engine, the speed suddenly exceeds the no-load speed greatly, and the speed cannot be reduced after the throttle is released. Accompanied by a huge noise and smoke, the engine is no longer under control. That is the "racing" problem of the diesel engine. The bad effects caused by “racing” problem Because of the huge mechanical force produced by "flying car", it is very easy to cause malignant accidents such as broken connecting rod or connecting rod bolt of engine and cylinder score. After exceeding its limit, serious accidents such as damages to cylinder block, connecting rod, crankshaft and piston, cylinder liner and cylinder head will occur, and even cause casualties. Therefore, urgent measures must be taken immediately to stop "racing" problem. The causes of “racing” (1) The fuel supply rod of the injection pump is stuck in the maximum fuel supply position. (2) The oil supply tie rod is separated from the transmission plate, and the oil supply tie rod is out of control. (3) The lubricate oil is added too much to the governor, or the oil level in the governor is too high due to oil leakage at the shoulder of the plunger sleeve. (4) The failure of oil supply regulation due to the damage of speed regulating spring or plunger spring. (5) The oil level in the air filter is so high that the lubricate oil is sucked into the cylinder. (6) The preheating plug is damaged and diesel enters into the combustion chamber from the intake pipe. The signs and teatments of "racing" A.Cutting off the diesel supply is sensible in principle, but it doesn’t very effective in practice. Because when cut off the diesel supply, the diesel remained on the top of piston which cannot be burned perfectly is enough to keep burning for a period of time, the speed of the generator cannot be lowered.   B.Actually, cutting off the air supply is the most effective way. Without the oxygen in the air, the fuel cannot continue to burn. The method of cutting of air supply is different according to different engine structure. If there are decompression mechanisms, the engine should be decompressed immediately; If there are mechanical or pneumatic control of the intake and exhaust brake devices, pneumatic brake shall be applied immediately; If these mechanisms are not available, the tubular air intake or the engine intake should be blocked immediately. This method is used widely by many engineers. [View Details]
  • Summer Maintenance Rules for Diesel Generator Set

    It’s hot summer now, as the temperature rises, more and more electricity is being used, and many areas will be in the state of electricity tension. As a result, many users are starting to use diesel generators as standby power. But how to make the diesel generator set safe during summer? 1.  A comprehensive inspection of the diesel generator set is necessary. Replace or clean the generator’s oil filters, diesel filters and air filters, replace the oil and antifreeze in the engine cylinder. Before starting it, check if the start-up battery voltage of the generator set is normal or not, if it’s abnormal, the generator won’t be started successfully. 2. Check and make sure that the ventilation of generator room is good, cool the generator room if condition allowed. Since the diesel generator set itself generates a large amount of heat during use, only by ensuring the temperature of the generator room can the generator set avoid having high water temperature and low oil pressure. 3.  Make proper use of closed cooling system. The cooling system should be used of high-quality coolant with anti-corrosion, anti-boiling, antifreeze and waterproof, and must be guaranteed to receive results in the use of the seal. 4.  Avoid the engine working too long under heavy load. When the engine is under heavy load, it will cause the high temperature of the coolant. Take small power car for example, some small power cars’ owners often step on the throttle to run fast and take in more things, and the air conditioner is running too long in the summer, it’s easy to cause the engine “boiling”. Therefore, when the diesel generator set needs high power operation, it’s necessary to replace it with low gear in time, in order to reduce the engine load and prevent the engine from “boiling”. [View Details]
  • Features of High-voltage Generator Set

    Features of High-voltage Generator Set [View Details]
  • Considerations for operating gas generator set

      1.Gas generator set’s room should be far away from open flame area; 2.Gas generator set’s room should be bright and spacious, require the installation of ventilator to ensure good ventilation; 3.When gas generator is installed, the base and foundation shall be in level. The shock pad is installed between the set and the base, and the contact area between the shock pad and the set is bigger than 60% 4.Indoor should install lights switches, wiring, and electrical appliances should take explosion-proof measures, and be fixed firmly; 5.Gas generator set’s room should comply with fire requirements, be equipped with fire extinguishers and other fire appliances; 6. Gas generator set’s room should be installed combustible gas alarm device, so that combustible gas leakage can be found in time 7.Below 60kW, single gas engine gas pipeline outside the main pipe diameter should be not less than 2 inches, the internal diameter of the part near the engine shall be not less than 1 inch ! Gas generator sets over 60kW respectively are 3 inches and 2 inches. And the set must install gas valve (stainless steel ball valve), type drain valve, anti tempering device, When gas pipeline welding completed, clean up welding slag (with high-pressure air); 8.The gas must have desulfurization, dehydration, dedusting, the sulfur content ≤0.25nm³, hydrogen ≤ 10%; 9.The cooling water of the gas generator set must be softened water. [View Details]

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