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An overview of diesel generator technology

Principle of diesel generator
The diesel engine drives the generator to turn the energy of diesel into electricity.
In the cylinder of the diesel engine, the clean air filtered by the air filter is fully mixed with the high-pressure atomized diesel fuel ejected from the nozzle. Under the extrusion of the piston, the volume is reduced and the temperature rises rapidly to reach the ignition point of the diesel. The diesel is ignited, the mixture gas is burning fiercely, the volume expands rapidly, pushing the piston down, is called "do work". Each cylinder works in a certain order, and the thrust acting on the piston passes through the connecting rod into a force that drives the crankshaft to rotate, thereby driving the crankshaft to rotate.
When the brushless synchronous alternator is installed with the diesel engine crankshaft, the rotor of the generator can be driven by the rotation of the diesel engine. Using the electromagnetic induction principle, the generator will output the induction electromotive force, and the current can be generated by the closed load loop.
The basic principle of the generator set is described here. In order to get stable and stable power output, a series of diesel engines and generators are needed to control, protect devices and circuits.
Pre operation inspection of diesel generator
1. Appearance check:
Whether the engine is damaged outside, missing parts, whether the screws are loose, whether the generator output line or control line is loose or not.
Two. Fuel system:
1, whether the fuel quantity is enough, whether there is oil leakage or loose pipe fittings in the wiring piping, and exclude the air in the fuel system.
2, lubricating system: is engine oil sufficient? After the overhaul of the engine, the heavy haul engine must operate at the initial operation for 50 hours.
A, engine oil replacement.
B, engine oil filter replacement.
C, engine diesel filter replacement.
Check and adjust the clearance of D and valve valve.
E, the inspection of the external screw of the engine.
3. Cooling system: is the cooling radiator adequate? Add rust inhibitor.
4. Battery: is the electrolyte of the battery on the normal level? Is the voltage correct? Is there any loosening of the joint?
5. Does the charger operate normally?
6. Exhaust system: whether the muffler is damaged or not, and whether the exhaust pipe is firmly installed.
7. The flammable objects and sundries can not be stored around the unit.
8. Whether the ventilation of the generator room is good.
9. No casual access to the machine room.
Start / stop of diesel generator
1. Manual test machine
1, generator manual start: first test the alarm system is normal, after the control switch is cut in manual (MAN) position, the generator can start automatically.
2, generator shutdown: switch the control switch to stop (STOP) or press the red emergency stop button to stop the generator running. In case of emergency, the emergency stop button can be directly pressed to stop the engine. If the red emergency stop button is pressed down, it must be returned to the original position, otherwise the generator will not start.
Two. Automatic switching control
1, the control switch is cut to automatic (AUTO), and the power automatic switch switch (ATS) control switch should also be used in the automatic position. When the city power stops, A. T. S will give the starting signal to the generator control system, and the generator will start automatically.
2, when the control switch is cut to stop (STOP) or remain automatic, the ATS will send the stop signal immediately after the electricity has been restored, and the generator will stop automatically. Note: the operation of the generator, due to failure (over speed, high water temperature, low oil pressure, etc.) when the automatic shutdown, after the troubleshooting button to reset the button to prepare for restarting.
Several points of attention in the operation of diesel generators:
1. AC ammeter: if the indicator is normal, switch the current switch to measure the phase current value between the phases. The difference between the phases is best not to exceed 10%.
2. AC voltmeter: the voltage shown by the watch is normal.
3. is the oil pressure indicated by the oil pressure gauge in the normal range?
4. charging table: whether the pointer is in (+) direction.
5. is the water temperature indicated by the thermometer in the normal range of 65 ~ 93?
6. tachometer: whether the engine's rotation is appropriate. (60Hz is 1800 rpm)
7. is there any abnormal sound or vibration in the generator engine?
Why does the exhaust pipe sometimes drip oil when the diesel generator load is too low?
Because there are many forms of pressure seal in the engine, such as cylinder sleeve piston piston ring, turbocharger turbocharger rotor shaft, this kind of seal can make full use of the engine when it has about 1/3 load, and there may be a slight leakage in the hour of load. Therefore, overseas engine manufacturers generally emphasized in their manuals.
If the unit runs under a small load, the following faults will occur as the running time continues.
The 1. piston cylinder liner is not well sealed, the oil goes up and goes into the combustion chamber, and the blue smoke is discharged.
2. for supercharged diesel engines, due to low load and no load, the boost pressure is low. The sealing effect of turbocharger oil seal (non-contact) is easy to cause. The oil moves into the plenum chamber and enters the cylinder with intake gas.
3. up to the cylinder of oil to burn, a part of the oil can not be completely burned, in the valve, inlet, piston top, piston ring and other parts of coke formation, and some part of the exhaust discharge. In this way, the cylinder will gradually accumulate oil in the exhaust passage and form carbon deposits.
4. the turbocharger's internal combustion chamber oil accumulates to a certain extent and leaks out from the joint surface of the supercharger.
5. long term small load operation will lead to more serious wear and tear of motor parts and deterioration of engine combustion environment.
Therefore, the diesel engine manufacturers abroad emphasize that both the natural suction type and the turbocharged model should be used to minimize the low load / idle running time, and that the minimum load should not be less than 25% - 30% of the power rating of the unit.