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1. Which six systems are included in the basic equipment of a diesel generating set? Answer: (1) Oil lubrication system; (2) Fuel system; (3) Control and protection system; (4) Cooling and cooling system; (5) Exhaust system; (6) Starting system;
2. Why do we recommend customers to use oils recommended by a professional company in sales work? A: Engine oil is the engine's blood. Once the customer uses unqualified engine oil, it will cause the engine to cause shaft bearing seizure, gear teething, crankshaft deformation and fracture and other serious accidents, until the whole aircraft is scrapped. Specific oil selection and use precautions are detailed in the relevant articles of this edition.
3. Why does the new machine need to change oil and oil filter after using it for a period of time? A: The new machine will inevitably have impurities in the oil sump during the run-in period, which will cause physical or chemical changes in the oil and oil filter. Generator professional maintenance network, there are professionals for your related maintenance.
4. Why do we require customers to install the unit when the exhaust pipe is tilted 5-10 degrees downwards? Answer: The main reason is to prevent rainwater from entering the exhaust pipe, leading to a major accident.
5, General diesel engines are equipped with manual oil pump and exhaust bolts, what is its role? A: Used to remove the air in the fuel pipe before starting.
6. How to divide the diesel generator automation level? A: manual, self-start, self-start and automatic power conversion cabinet, remote three remote (remote control, remote measurement, remote monitoring.)
7. Why is the generator's outlet voltage standard 400V instead of 380V? Answer: Because of the voltage drop after the outgoing line.
8. Why does the site of the diesel generator set require air to flow smoothly? A: The output of a diesel engine is directly affected by the amount of air sucked in and the air quality. The generator must have enough air to cool it. Therefore, the use of the venue must be airy.
9. Why shouldn't the tool be turned too tightly when installing the oil filter, diesel filter, or oil-water separator, and just turn it to oil-free? A: Because if the seal is rotated too tightly, the sealing ring will thermally expand under the effect of the oil bubble and the temperature of the body, causing great stress. Causes damage to the filter housing or separator housing itself. What's more serious is the damage to the body's aunt that cannot be repaired.
10. How to identify fake and counterfeit domestic diesel engines? A: First check whether there is a factory certificate and a product certificate. These are the “certificates†of the diesel engine and must be available. Check the three major numbers on the certificate 1) the nameplate number;
2) Body number (generally on the plane where the flywheel end is mechanically machined, the font is convex); 3) The oil pump nameplate number. Checking these three numbers with the actual number on the diesel engine must be accurate. If there are any doubts, these three major numbers can be reported to the manufacturer for verification.
11. After operating an electrician to take over a diesel generator, what are the three main points to verify? Answer: 1) Verify the unit's true useful power. Then determine the economic power, and standby power. The method for verifying the true useful power of the unit is: a diesel engine's 12-hour rated power multiplied by 0.9 to obtain a data (kw). If the rated power of the generator is less than or equal to the data, the rated power of the generator is defined as the actual useful power of the unit. If the rated power of the generator is greater than the data, the data must be used as the actual useful power of the unit.
2) Verify what kind of self-protection features the unit has. 3) Verify 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 a elevator starter motor 22KW, should be equipped with how much generator? A: 22 * ​​7 = 154KW (Elevator is a direct load start model, instantaneous starting current is generally 7 times the rated current,
In order to ensure the uniform speed of the elevator. (ie at least 154kW generator set)
13. How to calculate the optimal power (economic power) of the generator set? Answer: P best = 3/4*P rated (ie 0.75 times rated power).
14. What does the state require that the engine power of a general generator set should be greater than the generator power? Answer: 10.
15. Some generator engine power is expressed in horsepower. How does horsepower and international unit kilowatts be converted? Answer: 1 horsepower = 0.735 kilowatts, 1 kilowatt = 1.36 horsepower.
16, how to calculate the current of the three-phase generator? Answer: I = P / (√ 3Ucosφ) that is, current = power (watts) / (√ 3 * 400 (volts) * 0.8).
The simplified calculation 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. China is used to express the capacity of transformers and UPS.
2) The active power is 0.8 times the apparent power. The unit is KW. China is accustomed to power generation equipment and electrical equipment. 3) The rated power of a diesel generator refers to the power that can be continuously operated 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 of the rated power, which is the output power of the diesel generator set that can operate for a long time without time limitation. At this power operation, the fuel is the most economical and the failure rate is the lowest.
18. Why does the diesel generator set not be allowed to operate for a long period of time below 50% of the rated power? A: The increase in oil consumption, diesel engine is easy to coke, increase the failure rate, shorten the overhaul cycle.
19, the actual output power of the generator when the power meter is based on the current meter or prevail? A: The current meter is used as the reference. The power meter is for reference only.
20. The frequency and voltage of a generator set are not stable. The question is whether it is an engine or a generator? A: It lies in the engine.
21. The frequency of a generator set is stable and the voltage is unstable. The question is whether it is an engine or a generator? A: It is a generator.
22. What is the problem of generator demagnetization and how should it be handled? Answer: The generator will not be used for a long time, resulting in the loss of residual magnetism contained in the iron core before leaving the factory. The excitation coil cannot build up the required magnetic field. At this time, the engine is running normally but no power is generated. This phenomenon is new. Or there are more units that are not used for a long time. Processing methods: 1) Press the excitation button with the excitation button, 2) With no excitation button, charge it with the battery, 3) With a light bulb load, speeding for a few seconds.
23. After a period of time, the generator set found that everything else was normal but the power was reduced. What was the main reason? Answer: a. The air filter is too dirty to suck in enough air. 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. It must be replaced or cleaned. c. The ignition timing is not correct and must be adjusted.
24. The voltage and frequency of a generator set with load are stable, but the current is unstable. Where are the problems? A: The problem is that the customer's load is not stable, and the generator quality is absolutely no problem.
25. The frequency of a generator set is not stable. What are the major problems? A: The main problem lies in the unstable rotational speed of the generator.
26. What are the points that must be paid attention to in the use of diesel generator sets? Answer: 1) The water in the tank must be sufficient and work within the allowable temperature range.
2) Lubrication oil must be in place, but not excessive, and keep working within the allowable pressure range. 3) The frequency is stable at about 50 Hz and the voltage is stable at about 400V. 4) Three-phase current is within the rated range.
27. Which parts of the diesel generator set need frequent replacement or cleaning? A: Diesel filters, oil filters, air filters. (Individual units also have water filters)
28. What are the main advantages of brushless generators? Answer: (1) Maintenance of carbon brushes is eliminated; (2) Resistance to radio interference; (3) Loss of loss of magnetization.
29. What is the general insulation level of domestic generators? A: Domestic machine B; Marathon brand machine and Leroy Summa brand machine and Steinford brand machine are H class.
30. What gasoline engine engine fuel needs gasoline and engine oil mix? A: Two-stroke gasoline engine.
31. What are the conditions for the use of two generator sets in parallel? What device to complete the parallel operation? Answer: The conditions for parallel use are the same voltage, frequency, and phase of the two machines. Commonly known as "three simultaneous." Use a dedicated parallel device to complete the parallel operation. It is generally recommended to use a fully automatic cabinet. Try not to manually merge. Because the success or failure of manual paralleling depends on human experience. The author has ventured over 20 years of experience in electric power work, and the reliable success rate of manual parallel diesel generators is equal to zero. Never use the concept of manual parallelism in the mains power system to apply a small power system, because the protection level of the two is completely different.
32. What is the power factor of the three-phase generator? Can a power compensator be added to increase the power factor? A: The power factor is 0.8. No, because the charging and discharging of the capacitor can cause fluctuations in the small power supply. And the unit is oscillating.
33. Why do we require customers to perform a tightening of all electrical contact parts after each 200 hours of operation of the unit? A: The diesel generator is a vibration machine. And many domestically produced or assembled units do not use double nuts. The use of a spring washer is useless. Once the electrical fastener is loosened, a large contact resistance is generated, resulting in abnormal operation of the unit.
34. Why does the generator room have to be clean and free from floating sand on the ground? A: If the diesel engine inhales dirty air, the power will drop; if the generator inhales impurities such as sand, it will cause insulation damage between the stator and rotor gaps, resulting in burning.
35. Why doesn't the user generally recommend neutral grounding during installation in recent years? A: 1) The self-regulating function of the new generation of generators is greatly enhanced; 2) In practice, the lightning failure rate of the neutral-grounded units is found to be high. 3) The grounding quality is high and the average user cannot do it. Unsafe grounding is not as good as grounding. 4) The neutral grounded unit will cover the load leakage faults and ground faults, and these faults and errors cannot be exposed under the mains power supply condition.
36. What should be taken care of when using neutral ungrounded units? Answer: The 0 line may be live because the capacitor voltage between the live line and the neutral point cannot be eliminated. The operator must see the 0 line as a live body. Can not be treated according to commercial power.
37. How can UPS and diesel generators be matched in order to ensure the stability of UPS output? Answer: 1) UPS is generally expressed by the apparent power KVA, which is first multiplied by 0.8 to the unit KW that is consistent with the generator active power.
2) If a general generator is used, multiply the active power of the UPS by 2 to determine that the generator power, ie the generator power, is twice the UPS power. 3) If a PMG (permanent magnet machine excitation) generator is used, the power of the generator is determined by multiplying the power of the UPS by 1.2, that is, the generator power is 1.2 times the UPS power.
38, indicating the voltage or voltage of 500V electronic or electrical components, can be used for diesel generator control cabinet? A: No. Because the 400/230V voltage marked on the diesel generator set is an 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.
39. Are all diesel generator sets self-protected? A: No. At present, there are even some belts in the same brand of units on the market. The user must know for himself when purchasing the unit. It is best to write a written document as an attachment to the contract. General low-priced machines do not have self-protection function.
40. What are the benefits for customers who have purchased self-start but have not purchased an automatic conversion cabinet? Answer: 1) Once a power outage occurs in the city network, the unit will start automatically to speed up the manual transmission time;
2) If the lighting line is taken out at the front end of the air switch, it can also ensure that the lighting of the engine room is not affected by the power outage, so as to facilitate the operation of the operator;
41. What does the common symbol GF of a domestic generator set mean? A: On behalf of double meaning: a) Power frequency generator set is suitable for China's general power 50HZ generator set. b) Domestic generator sets.
42. Does the load on the generator must maintain three-phase balance during use? Answer: Yes. The maximum deviation must not exceed 25%.
43. Which four strokes do four-stroke diesel engines refer to? A: Inhalation, compression, work, exhaust.
44. What is the biggest difference between a diesel engine and a gasoline engine? Answer: 1) The cylinder is different from the pressurized material. The diesel engine compresses air during the compression stroke; the gasoline engine compresses the gasoline and air mixture during the compression stroke. 2) Different ignition methods. Diesel engines rely on atomized diesel fuel for spontaneous combustion with high pressure gas; gasoline engines rely on spark plug ignition.
45. What does "two-vote-three system" specifically refer to in the power system? A: The second ticket refers to the work ticket and the operation ticket. That is, any work and operation performed on the power equipment. Must first receive the work ticket and operation ticket issued by the person in charge of duty. The parties must execute the ticket. The three systems refer to the handover system, the circuit inspection system, and the equipment switching system.
46. ​​What is the so-called three-phase four-wire system? Answer: There are 4 generating lines, of which 3 are fire wires and 1 is zero wires. The voltage between FireWire and FireWire is 380V. 220V between live and neutral lines.
47, three-phase short-circuit is how is it? What are the consequences? Answer: The direct short circuit is a three-phase short circuit without any load between the fire wires. The consequences are terribly terrible, and serious ones will lead to aircraft death.
48. What is the so-called reverse power transmission? What are the two serious consequences? Answer: The condition of sending power to the city grid by a generator is called reverse power transmission. There are two serious consequences: a) There is no power outage in the city network, and the city grid power supply and self-provided generator power supply will not be synchronized in the same period, and it will destroy the unit. If the capacity of the self-provided generator is large, it will also cause the city network to oscillate. b) The city network has been outage and is undergoing maintenance, and its own generator is being reversed. It will cause electrician maintenance personnel to electrocution.
49. Why should the commissioning personnel thoroughly inspect all fixing bolts of the unit before they are fixed? Are all line interfaces intact? Answer: After long-distance transportation, the crew sometimes can't loosen or drop the plug and the line interface. The light affects the debugging and the damage to the machine.
50. What level of energy is energy? What are the characteristics of AC? A: Electric energy belongs to secondary energy. AC is converted by mechanical energy. DC is converted by chemical energy. The characteristic of AC is that it cannot be stored.
51. What conditions do the generator set meet before it can be turned on and off? A: The water-cooled unit has a water temperature of 56 degrees Celsius. Air cooling unit, body slightly hot. The voltage frequency is normal at no load. Oil pressure is normal. Before closing power transmission.
52. What is the order of load after power-on and power-off? A: Take the load from big to small.
53. What is the order of unloading before shutdown? Answer: The load is removed from small to large in order, and finally shut down.
54, why can not load off, boot? A: The emergency shutdown with load shutdown is a big impact on the unit. It is a violation of the operation of a load with a boot to damage the power equipment of the power generation equipment.
55. What should you watch out for when using diesel generators in winter? Answer: 1) Pay attention to the fact that the tank must not be frozen. Preventive measures include the addition of special long-term anti-rust, antifreeze or electrothermal equipment to ensure that the room temperature is above the freezing point. 2) Do not bake with open flames. 3) The no-load warm-up time is a bit longer before power is transmitted.
Generator Basics - Use - Maintenance - Maintenance
As all technologies are updated and developed, the following is for reference only: