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Home >NEWS>Group news

50 Frequently Asked Questions on Diesel Generating Set

Date:2016-09-24 09:37:02

1, two generators and machine use conditions? What device to complete the machine and work?
A: The conditions for parallel use of the two machines instantaneous voltage, frequency, phase the same. Commonly known as "three simultaneous." With a dedicated parallel device to complete and work. It is generally recommended to use fully automatic and cabinet. Try not to manually and machine. Because the success of manual and machine failure depends on human experience. I have more than 20 years of experience in the work of electric power boldly put it, diesel generator manual and the reliability of the machine is equal to the success rate of 0. Must not be large power supply system can be used manually and the concept of small power to apply the system, because the two levels of protection are completely different.

2, the power factor of the three-phase generator is how much? Can the power compensator be added to improve the power factor?
A: The power factor is 0.8. No, because the capacitor charge and discharge will lead to small power supply fluctuations. And unit oscillation.

3, Why do we require customers, the unit every 200 hours after the operation, to conduct a fastening of all electrical contacts work?
A: The diesel generator is a vibration work. And many domestic production or assembly of the unit with the double-nut useless. The use of the spring gasket useless, once the electrical fasteners loose, will have a great contact resistance, resulting in unit operation is not normal.

4, why the generator room must ensure clean, no sand on the ground?
A: If the diesel engine inhaled dirty air will power down; generator if the inhalation of sand and other impurities will make the rotor between the gap between the insulation damage, heavy cause burn.

5, why since 2002 my company generally does not recommend the user to install neutral grounding?
A: 1) a new generation of generators greatly enhanced self-regulation function;
2) in practice found that the neutral point grounding unit lightning high failure rate.
3) grounding quality requirements are high, the average user can not do. Unsafe ground is not grounded.
4) Neutral grounded units will cover the load leakage fault and ground fault, and these failures and errors in the mains power supply current situation can not be exposed.

6, the neutral point is not grounded units, use should pay attention to what the problem?
A: 0 line may be charged, because the line between the neutral point and the capacitor voltage can not be eliminated. Operators must view the 0-wire as a live body. Can not be used to deal with electricity.

7, UPS and diesel generators how power matching, in order to ensure the stability of UPS output?
A: 1) UPS generally used apparent power KVA said, first by 0.8 converted into active power and generator unit consistent with the KW.
2) If the general generator, the UPS active power is multiplied by 2 to determine the distribution of power generator, the generator power is twice the UPS power.
3) If the generator with PMG (permanent magnet excitation) is used, the generator power is determined by multiplying the power of the UPS by 1.2, ie the generator power is 1.2 times the UPS power.

8, indicate the voltage 500V of electronic or electrical components, can be used for diesel generator control cabinet?
A: No. Because the diesel generator set on the 400 / 230V voltage is the effective voltage. The peak voltage is 1.414 times the effective voltage. The peak voltage of the diesel generator is Umax = 566 / 325V.

9, all the diesel generators are with self-protection function?
A: No. Currently on the market even in the same brand of the unit with some, some without. Users have to figure out when they buy the unit. The best written material as a contract annex. General low-cost machines are not with self-protection.

10, how to identify counterfeit domestic fake diesel engine?
A: First check whether the factory certificate and product certification, they are the diesel engine factory "proof of identity" is a must. And then check the certificate on the three major numbers 1) nameplate number; 2) body number (in general, in the flywheel side of the mechanical cutting of the plane, the font is convex body); 3) pump nameplate number. These three numbers with the actual number of diesel engines to check, must be accurate. If there is doubt can be the three numbers reported to the manufacturer to verify.

11, the operation electrician took over the diesel generator, the first to verify which three points?
Answer: 1) Verify the real useful power of the unit. And then determine the economic power, and standby power. The method of determining the true and useful power of the unit is: the diesel engine 12 hours rated power multiplied by 0.9 to produce a data (kw), if the generator rated power less than or equal to the data, the generator rated power as the unit real useful power, If the generator rated power is greater than the data, the data must be used as the unit's real useful power.
2) Verify which self-protection functions the unit is equipped with.
3) verify the unit's electrical wiring is qualified, protective earth is reliable, three-phase load is basically balanced.

12, there is a lift starter motor is 22KW, should be equipped with much of the generating units?
A: 22 * 7 = 154KW (lift for the direct start with the load model, the instantaneous start-up current is generally rated current of 7 times in order to ensure uniform movement of the elevator). (That is, at least 154KW should be equipped with generating units)

13, the best use of power generating units (economic power) how to calculate?
A: P best = 3/4 * P rated (ie 0.75 times the rated power).

14, the state provides generators in general engine power should be much larger than the generator power? A: 10 ℅.

15, and some generating units with horsepower that engine power, horsepower and international units of kilowatts between how conversion?
A: 1 horsepower = 0.735 kilowatts, 1 kilowatt = 1.36 horsepower.

16, three-phase generator current how to calculate?
Answer: I = P / (√3 Ucos φ)
Namely, current = power (watts) / (√3 * 400 (volts) * 0.8).
Simplified formula: I (A) = unit rated power (KW) * 1.8

17, apparent power, active power, rated power, maximum power, the relationship between economic power?
A: 1) Apparent power in units of KVA, China is used to express the capacity of transformers and UPS.
2) active power is 0.8 times the apparent power, the unit is KW, China is used to power generation equipment and electrical equipment.
3) The rated power of diesel generator sets is 12 hours of continuous operation of power.
4) The maximum power is 1.1 times the rated power, but only allowed within 12 hours 1 hour.
5) economic power is 0.75 times the rated power, diesel generators are not subject to time constraints can be long-term operation of the output power. In this power operation, the fuel province, the lowest failure rate.

18, why do not allow diesel generator sets below 50% of rated power in the case of long-term operation.
A: oil consumption increases, the diesel engine is easy to charcoal, increasing the failure rate, shorten the overhaul period.

19, the actual operation of the generator output power to the power meter or subject to ammeter?
A: The ammeter shall prevail, the power meter only for reference.

20, a generator frequency and voltage are not stable The problem lies in the engine or generator?
A: Is the engine.

21, a generator frequency stability, voltage instability The problem lies in the engine or the generator?
A: lies in the generator.

22, generator excitation loss is how, how to deal with?
A: The generator is not used for a long time, resulting in the factory included in the core of the residual magnetism lost, the excitation coil can not afford the magnetic field, then the engine is running but not electricity, such phenomena. Or long-term unused units more.
Treatment method: 1) With excitation button click the excitation button, 2) no excitation button, with the battery to its magnetization, 3) with a light bulb load, speeding for a few seconds.

23, the generator set with a period of time and found everything else is normal but the power down, the main reason for that?
A: a, the air filter is dirty, inhaled air is not enough, then have to clean or replace the air filter.
B, fuel filter is dirty, fuel injection is not enough to be replaced or cleaned.
C, ignition timing is not correct, to be adjusted.

24, there is a generator with a load after the voltage and frequency are stable, but the current instability, the problem where?
A: The problem is that the customer's load is not stable, and the quality of the generator is absolutely no problem.

25, the frequency of a generating unit instability, the main problem?
A: The main problem is that the speed of the generator is not stable.

26, diesel generator set in the use of critical must pay attention to what points?
A: 1) The water in the tank must be sufficient, and keep the temperature in the allowed work.
2) Lubricating oil must be in place, but not excessive, and keep the pressure within the allowable work.
3) frequency stability in 50HZ or so, the voltage stability in 400V or so.
4) three-phase current are within the rated range.

27, diesel generators need to frequently replace or clean the parts which have several?
A: diesel filters, oil filters, air filters. (Individual units also have water filters)

28. What are the main advantages of brushless generators?
A: (1) from carbon brush maintenance;
(2) resistance to radio interference;
(3) to reduce the loss of magnetic failure.

29, the insulation level of domestic generators is generally much?
A: Domestic machine B-class; Marathon brand and Leroy Somer brand machine and the brand name for the H-level f Dan.

30, what gasoline engine fuel to be gasoline, oil mixed?
A: Two-stroke gasoline engine.

31, diesel generator set which includes six basic systems?
A: (1) oil lubrication system;
(2) fuel systems;
(3) control and protection system;
(4) cooling and cooling system;
(5) Exhaust system;
(6) starting system;

32, why do we work in the sales efforts to recommend customers to use my company recommended oil?
A: The oil is the engine's blood, once the customer using the oil will lead to failure of the engine bearing bite death, gear teeth, crankshaft deformation fracture and other serious accidents, until the whole machine scrapped.

33, why the new machine to use after a period of time need to replace the oil and oil filter?
A: The new machine in the run-in period will inevitably have impurities into the oil sump, the oil and oil filter physical or chemical qualitative change.

34, why do we require customers to install the unit, the exhaust pipe to tilt down 5-10 degrees?
A: to prevent rain into the exhaust pipe, leading to major accidents.

35, the general engine are equipped with diesel engine manual exhaust pump and exhaust bolts, its role is what? A: Used to exclude the air before the fuel pipe.

36, diesel generators how to grade automation?
A: manual, since the start, since the start plus automatic electricity conversion cabinet, remote three remote (remote control, telemetry, remote monitoring.)

36, diesel generators how to grade automation?
A: manual, since the start, since the start plus automatic electricity conversion cabinet, remote three remote (remote control, telemetry, remote monitoring.)

37, why the generator outlet voltage standard is 400V instead of 380V?
A: Because the line after the outlet voltage drop loss.

38, why require the use of diesel generator sets of venues must be smooth air?
A: The output of the diesel engine directly by the amount of air inhaled and the impact of air quality, the generator must have sufficient air to give cooling. So use the site must be air.

39, why the installation of oil filters, diesel filters, oil-water separator should not use the tools to spin the three devices too tight, but only by hand spin to the oil can not?
A: Because if the rotation is too tight, the seal ring by the oil and the role of the body temperature will be thermal expansion, resulting in a lot of stress. Resulting in damage to the filter housing or the separator housing itself. More serious is the cause of the body Luo mother damage so can not repair.

40, the customer purchased from the start, but not to buy automatic conversion cabinet will have any good?
A: 1) Once the city network power failure, the unit will automatically start to speed up the artificial power transmission time;
2) If the front of the air switch connected to the lighting line can also ensure that the engine room lighting from the impact of power to facilitate the operation of the staff;

41, generating units to meet what conditions can be closed to send electricity?
A: The water-cooled unit, the water temperature reached 56 degrees Celsius.
Air-cooled unit, the body micro-heat.
No-load voltage frequency is normal. Oil pressure is normal. Can be closed to send electricity.

42, after starting the power transmission with the load order is what?
A: The load from top to bottom in order to bring.

43, shut down before unloading load order is what?
A: The load from small to large followed by unloading, and finally shut down.

44, why not bring the load off, boot?
A: The shutdown with the load is an emergency shutdown, a greater impact on the unit. With a boot is illegal operation of power generation equipment, electrical equipment will bring damage.

45, the use of diesel generators in winter should pay attention to what?
A: 1) Note that the tank is absolutely not frozen, there is a special method to prevent long-term anti-rust, antifreeze or the use of electric equipment to ensure room temperature above the freezing point.
2) No open flame baking.
3) No-load preheat time to be slightly longer, before transmission.

46, the so-called three-phase four-wire system is how the same thing?
A: There are four qualifying units, of which three are FireWire, one for the zero line. FireWire and FireWire voltage between 380V. Between the line of fire and the zero line is 220V.

47, three-phase short-circuit is how one thing? What are the consequences?
A: FireWire without any load between the direct short circuit is three-phase short circuit. Its consequences are terrible, serious will lead to machine crash.

48, the so-called reverse transmission is going on? Which will have two serious consequences?
A: The self-provided generator to the city network transmission is called reverse power transmission. There are two serious consequences:
A) the city network without power outages, the city network power and generator-generated power generation and non-synchronous machine, will destroy the unit. If the generator-owned large capacity, but also make the city network shocks.
B) the city network is power outage is under maintenance, its own generator reverse power transmission. It will make power supply maintenance personnel electrocuted death.

49, why the commissioning personnel must be fully checked before debugging all the bolts fixed unit is intact? Are all line interfaces intact?
A: The unit after long-distance transport, and sometimes inevitably have bolts and line interface loosening or fall, the light impact of debugging, while the damage to the machine.

50, which energy is energy? What are the characteristics of AC?
A: power is secondary energy, alternating current from the mechanical energy conversion over, direct current from chemical energy can be converted, the characteristics of AC can not be stored, is found with.