Gasoline generatorIt is usually composed of stator, rotor, end cover, bearing and other parts.An engine is a machine that converts chemical energy into mechanical energy. Its conversion process is actually a process of working cycle. In short, it generates kinetic energy by burning the fuel in the cylinder to drive the piston in the engine cylinder to reciprocate, thus driving the connecting rod connected to the piston and the crank connected to the connecting rod to reciprocate around the center of the crankshaft,And output power.
The stator is composed of stator core, wire wrapped winding, frame and other structural parts that fix these parts.The rotor is composed of rotor core (or magnetic pole, magnetic choke) winding, retaining ring, center ring, slip ring, fan, shaft and other parts.The stator and rotor of the generator are connected and assembled by the bearing and end cover, so that the rotor can rotate in the stator and do the movement of cutting magnetic lines of force, thus generating induced potential, which is led out through the terminal and connected to the circuit, and then generating current.
A working cycle includes four piston strokes (the so-called piston stroke refers to the process of the distance between the top dead center and the bottom dead center of the piston): intake stroke, compression stroke, expansion stroke (power stroke) and exhaust stroke.
Intake stroke
During this process, the inlet valve of the engine is opened and the exhaust valve is closed.As the piston moves from top dead center to bottom dead center, the volume of the cylinder above the piston increases, so that the pressure in the cylinder drops below atmospheric pressure, that is, vacuum suction is created in the cylinder, so that air is sucked into the cylinder through the intake pipe and inlet valve, and atomized gasoline is ejected from the fuel injection nozzle and fully mixed with air.At the end of air intake, the gas pressure in the cylinder is about 0.075-0.09MPa.At this time, the temperature of the combustible mixture in the cylinder has risen to 370-400K.
Compression stroke
In order to enable the combustible mixture sucked into the cylinder to burn rapidly to generate greater pressure, so that the engine can produce greater power, the combustible mixture must be compressed before combustion to reduce its volume, increase its density, and increase its temperature, that is, a compression process is required.In this process, the inlet and exhaust valves are all closed, and the crankshaft pushes the piston to move a stroke from BDC to TDC, that is, the compression stroke.At this time, the pressure of mixed gas will increase to 0.6-1.2MPa, and the temperature can reach 600-700K.
An important concept in this journey is the compression ratio.The so-called compression ratio is the ratio of the maximum volume of gas in the cylinder before compression to the minimum volume after compression.Generally, the higher the compression ratio, the higher the pressure and temperature of the mixture at the end of compression, and the faster the combustion speed. Therefore, the greater the power generated by the engine, the better the economy.The compression ratio of ordinary cars is between 8-10, but the newly launched Polo has reached a high compression ratio of 10.5, so its torque performance is relatively good.However, when the compression ratio is too large, the combustion can not be further improved, but abnormal combustion phenomena such as explosion and surface ignition will occur.
Burst combustion is an abnormal combustion caused by the spontaneous combustion of the end combustible mixture in the combustion chamber far from the ignition center due to the high gas pressure and temperature.During the burst combustion, the flame spreads outward at a very high speed, and even when the gas does not have time to expand, the temperature and pressure rise sharply, forming pressure waves and pushing forward at sound speed.When this pressure wave strikes the combustion chamber wall, a sharp cylinder knocking sound will be emitted.At the same time, it will also cause engine overheating and power reduction,Fuel consumptionAdd a series of adverse consequences.Severe explosion may even cause valve burning, bearing bush rupture, spark plug insulator breakdown and other mechanical damage.
In addition to flash, engines with high compression ratios may also face another problem: surface ignition.This is another abnormal combustion (also called hot ignition or precombustion) caused by the ignition of the mixture between the hot surface and the hot place in the cylinder (such as exhaust valve head, spark plug electrode and carbon deposit).When surface ignition occurs, there is also a strong knocking sound (relatively dull). The high pressure generated will increase the load of the engine and reduce its service life.
Expansion stroke
During this process, the inlet and exhaust valves are still closed.When the piston is close to TDC, the spark plug emits an electric spark, igniting the compressed combustible mixture.After the combustible mixture is burned, a large amount of heat energy is released, at this time, the pressure and temperature of the gas increase rapidly.The maximum pressure it can reach can reach 3-5 MPa, and the corresponding temperature can reach 2200-2800K.The high-temperature and high-pressure gas pushes the piston to move from top dead center to bottom dead center, making the crank rotate through the connecting rod and outputting mechanical energy. In addition to keeping the engine running, the rest is used for external work.During the movement of the piston, the volume in the cylinder increases, and the gas pressure and temperature drop rapidly. At the end of this journey, the pressure drops to 0.3-0.5MPa, and the temperature is 1300-1600K.
Exhaust stroke
When the expansion stroke (power stroke) is close to the end, the exhaust valve will open and exhaust freely by the pressure of exhaust gas. When the piston reaches the bottom dead center and then moves up to the top dead center, exhaust gas will be forced into the atmosphere, which is the exhaust stroke.During this stroke, the pressure in the cylinder is slightly higher than the atmospheric pressure, about 0.105-0.115 MPa.When the piston reaches near TDC, the exhaust stroke ends, and the exhaust gas temperature is about 900-1200K.
Therefore, we have introduced a working cycle of the engine. During this period, the piston moves four strokes back and forth between the top and bottom dead centers, and the crankshaft rotates two cycles accordingly.
Reliable: The stable automatic voltage regulation system and oil warning system are reassuring to use.
He has led the technology of internal combustion engine for nearly half a century, and his exquisite technology and rich experience are reflected in each engine to ensure that each engine has stable performance and reliable work in long-term operation, thus greatly saving maintenance time.
The use of automatic voltage regulator can automatically maintain the voltage stability when the equipment is loaded to ensure the supply of stable power. This unique design is particularly important for electrical equipment that is sensitive to voltage fluctuations.This isBrushed motorIt is superior to other generators and requires no maintenance.
Engine oil warning system:
When the oil level is too low, the oil warning system will automatically stop the engine to protect the engine from damage.
Main role
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Gasoline generator
In telecommunication systemGasoline generator setIt is usually used for emergency communication, emergency repair or backup power supply of small access network machine rooms and machine rooms.The gasoline generator set will be used under the following conditions:
1. In case of natural disasters, such as heavy rain and flood, large diesel units cannot be transported, and light gasoline units are the best choice to ensure the power supply of communication equipment in disaster areas;
2. In case of unstable mains power or power failure, small access network machine rooms or engine stations can use gasoline generator sets as backup power;
3. During emergency repair, if the emergency repair personnel need to carry a backup power supply, they can use the gasoline generator set (of course, if the power is high, the diesel generator set needs to be moved).
Maintenance method
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After the new generator or sealed generator is run in (the first 50 hours), the following maintenance work shall be carried out:
Clean or replace the air filter
Replace engine lubricating oil
Replace or clean the filter element of the lubricating oil filter
Retighten all bolts and nuts
The new generator shall avoid sudden load increase or high-speed operation as far as possible. The lubricating oil recommended by the manufacturer shall be used as far as possible. The lubricating oil of different brands shall not be mixed. The lubricating oil contains various additives. The mixing of lubricating oil of different brands will reduce the lubricating performance and cause abnormal wear of moving parts.
When filling the fuel tank, there should be a filter at the oil filling port, and it is better to put a filter cloth on it;The fuel must be left in the tank for more than 24 hours to allow water and impurities to settle before use;At ordinary times, the drain plug of the daily oil tank should be frequently opened to drain the water and sediment at the bottom.
Regular overhaul and planned maintenance are the key to extend the service life of the engine. The overhaul cycle and items should be properly adjusted according to the purpose, use conditions and properties of fuel and lubricating oil. If necessary, overhaul should be carried out in advance, and professional technicians should complete regular overhaul and maintenance as far as possible.
High quality imported generator sets are often valuable. They should be used reasonably, pay attention to daily maintenance, prevent early wear and tear, extend their service life, and keep them in a good standby state for rapid startup and operation, so as to make full use of everything.
Common faults
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Unable to generate electricity
(1) Wiring errors shall be checked and corrected according to the circuit diagram.
(2) The excitation winding of the main generator or exciter is wrongly connected, resulting in incorrect polarity.It is often caused by wrong wiring after replacing the excitation winding.It shall be checked and corrected.
(3) The rotating silicon rectification element is broken down and short circuited, and the positive and negative directions are connected.Use a multimeter to check the forward and reverse resistance of the rectification element and replace the damaged element.
(4) The excitation winding of the main generator is disconnected.Check and measure the excitation winding of the main generator with a multimeter. The resistance is infinite. Connect the excitation circuit.
(5) Each winding of the main generator or exciter has a serious short circuit. The armature winding has a short circuit, and generally has obvious overheating. The excitation winding has a short circuit, which can be judged by its branch resistance value.Replace the damaged winding.
No load voltage is too low
(For example, the line voltage is only about 100V)
(1) The excitation winding of exciter is broken.Check that the resistance of excitation winding of exciter shall be infinite.Replace the broken coil or connect the coil circuit.
(2) The main generator excitation winding is seriously short circuited.The current of exciter excitation winding is very large.The excitation winding of the main generator is seriously heated, the vibration increases, and the branch resistance of the excitation winding is much smaller than the normal value.Replace the short circuit coil.
（3）Automatic voltage regulatorFault.At rated speed, measure whether the output branch current value of the automatic voltage regulator is equal to the factory no-load characteristic of the motor.Repair the automatic voltage regulator.
No load voltage is too high
(1) The automatic voltage regulator is out of control.The excitation winding current of no-load exciter is too large.Check the automatic voltage regulator.
(2) The setting voltage is too high. Reset the voltage.
Exciter excitation current
(1) One or two of the rectifying elements are open circuit, and the forward and reverse directions are not connected. Use a multimeter to check and replace the damaged elements.
(2) The main generator or exciter excitation winding is partially short circuited, and the DC resistance value of each pole coil shall be measured.Replace the coil with short circuit fault.
(1) Check and correct the poor connection with the prime mover.After all bolts are fastened, ensure that the generator and prime mover axes are aligned and concentric.
（2）Rotor dynamic balanceBad, it occurs after the rotor is rewound, and the dynamic balance should be aligned.
(3) Measure the DC resistance of each pole in case of partial short circuit of excitation winding of main generator, and find out the fault point of short circuit.Replace the coil.
(4) The bearing is damaged and the bearing cover is generally overheated. Replace the bearing.
(5) The prime mover is faulty. Check the prime mover.
overheated
(1) The generator is overloaded, so that the load current and voltage do not exceed the rated value.
(2) If the load power factor is too low, adjust the load so that the excitation current does not exceed the rated value.
(3) If the speed is too low, adjust the speed to the rated value.
(4) Some windings of the generator are short circuited. Find out the short circuit, correct or replace the coil.
(5) The ventilation duct is blocked, remove the obstruction, disassemble the motor, and thoroughly blow out each air duct.
Bearing overheating
(1) The bearing is excessively worn after long-time use. Replace the bearing.
(2) The quality of lubricating grease is poor.Oils of different brands are mixed.There are impurities in the grease.If the grease is too much, remove the old grease and replace it with new grease after cleaning.
(3) The connection with the prime mover is not good, and the alignment is concentric.
The gasoline generator stops after starting, and the causes and treatment methods of easy flameout are as follows:
1. The air filter is seriously blocked.
Check the condition of the air filter.
2. Electric control board, actuatorspeed sensor And so on.
3. The oil circuit is blocked, the filter is blocked, and the fuel transfer pump is faulty.
Check whether the oil circuit is unblocked and replace it if necessaryDiesel filter。
4. Automatic protection function sets parameter offset.
Reset parameters.
5. The fuel injection nozzle is faulty.
Replace the oil nozzle.
6. DC power of automation unit is interrupted.
Check whether the battery voltage or power is sufficient.
Routine maintenance
Note: The following inspections shall be carried out before each use of the gasoline generator to ensure safe and normal use of the generator.
1. If the generator is not used for a long time (more than one month), the starting battery will lose power due to self discharge. Please use an external charger to charge the battery.
2. Check whether the gasoline in the fuel tank is sufficient.
3. Check the oil circuit switch and oil delivery pipeline for oil leakage.
4. Check whether the starting battery voltage is above 12V, and observe whether the battery appearance is damaged or leaked.
5. Observe the quality of the engine oil to determine whether it needs to be replaced.
6. Check whether the oil level is between the oil dipstick grids
matters needing attention
1) Theory guides practice.The basic principle and structure of small gasoline engines should be fully mastered before fault analysis and treatment can be carried out, especially for different models of gasoline engines, specific analysis of specific models should be carried out;
2) When a fault occurs, a comprehensive and scientific analysis and judgment should be carried out according to the site to ensure that the fault can be handled accurately, rather than by imagination or past so-called experience.The gasoline engine often has faults in the oil circuit, circuit and other parts at the same time, resulting in more complex fault phenomena. Sometimes different fault points will have similar phenomena, which will cause certain difficulties in troubleshooting.Through analyzing and thinking through the fault phenomena observed on site, we can imagine various possible causes of faults, analyze and compare them, and then determine the scope and location of faults.Then, from simple to complex, from the outside to the inside, analyze the circuit first, then analyze the oil circuit, then calibrate the ignition time, check the sequence of gas distribution timing, and compress the fault to a certain point;
3) Develop good habits, do a good job of necessary inspection before starting up, and regularly patrol the machine during operation to avoid sudden failures as far as possible;
4) At ordinary times, strictly carry out technical maintenance at all levels for the oil engine to ensure that the oil engine is in good working condition and avoid sudden failures and major accidents[1]。
Silencing treatment
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Gasoline generator setThe noise is characterized by wide frequency band spectrum, and the silencing equipment is required to be able to resist high air flow velocity, high temperature and high pressure, and is not afraid of water and moisture. When the temperature rises, the performance of the silencer changes little. According to this situation, micro perforated plate composite silencers are often used in the treatment.The double-layer structure with a hole diameter of 0.5~1mm and a perforation rate of 1%~3% is made of 0.5~1mm thin steel platemicropunch plate muffler It has good absorption effect for medium and high frequency noise.In case of multi-layer, the cavity thickness depends on the absorption frequency band. In case of low frequency 125~250Hz, the cavity thickness is 150~220mm, and in case of intermediate frequency 500~1000Hz, the cavity thickness is 80~120mm.When the high frequency is 2000~4000Hz, the cavity is 30~50mm. In order to prevent the propagation of sound waves along the pipe length in the micro perforated plate cavity, a transverse baffle shall be added every 0.5m for silencers that need a high noise reduction.The cross section of the double-layer micro perforated plate tube muffler is circular.
Common specifications
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Main power: 650w gasoline generator, 1KW gasoline generator
