AVR (Automatic voltage regulator) is an instrument that adjusts voltage by means of automatic control device.
Voltage regulator (referred to as AVR) is designed for AC brushless generators with fundamental wave, harmonic compound excitation or permanent magnet generator excitation (PMG system). Voltage regulator realizes the automatic regulation of generator output voltage by controlling the excitation current of generator AC exciter. Generator voltage regulator can be used for ordinary 60/50Hz as well as medium frequency 400Hz single or parallel generators. An AVR is at the heart of devices often called power conditioners or power stabilizers. The typical power conditioner is an automatic voltage regulator combined with one or more other power-quality capabilities, such as: 1) Surge suppression 2) Short circuit protection (circuit breaker) 3) Line noise reduction 4) Phase-to-phase voltage balancing 5) Harmonic filtering, etc. Power conditioners are typically used in low voltage (<600V) applications and sizes below 2,000KVA. In general, the AC automatic voltage regulator (AVR) is a device designed to regulate voltage automatically – that is, to take a fluctuating voltage level and turn it into a constant voltage level. Working principle of AVR The voltage regulator is an adjustment device that controls the generator output voltage within a specified range. Its function is to automatically control the generator voltage and keep it constant when the rotating speed of the generator changes, so as to prevent the generator voltage from being too high to burn out the electrical equipment and cause the battery to overcharge. At the same time, it also prevents the generator voltage from being too low, resulting in malfunctioning of electrical equipment and insufficient battery charge. Since the transmission ratio of generator to engine is fixed, the speed of generator will change with the change of engine speed. The power supply of generator to electric equipment and charging to battery both require its voltage to be stable, so it is necessary to adjust the output voltage of generator if the voltage is kept at a certain value basically. A synchronous generator regulator that maintains the synchronous generator voltage at a predetermined value or changes the terminal voltage as planned. When the terminal voltage and reactive power of the synchronous motor change, the output current of the exciter is automatically controlled according to the corresponding feedback signal to achieve the purpose of automatically regulating the terminal voltage or reactive power of the synchronous motor. According to the working principle, the voltage regulator of alternator is divided into: 1. Contact type voltage regulator Contact type voltage regulator was applied earlier, the regulator contact vibration frequency is slow, there is mechanical inertia and electromagnetic inertia, voltage regulation accuracy is low, contact is easy to generate sparks, large radio interference, poor reliability, short life, now has been eliminated. 2. Transistor regulator With the development of semiconductor technology, transistor regulator is adopted. The advantages is high switching frequency of triode, no sparks, high adjusting precision, light weight, small volume, long life, high reliability, small radio interference and so on. Now it is widely used in medium and low grade car model. 3. Ic regulator (Integrated circuit regulator) In addition to the advantages of the transistor regulator, the integrated circuit regulator has an ultra-small size and is installed inside the generator (also known as a built-in regulator), which reduces the external wiring and improves the cooling effect. It is now widely used in Santana, Audi and other car models. 4. Computer controlled regulator After the total load of the system is measured by the electric load detector, a signal is sent to the generator computer, and then the generator voltage regulator is controlled by the engine computer, and the magnetic field circuit is turned on and off in a timely manner, thereby reliably ensuring the normal operation of the electrical system, the battery is fully charged, and can reduce engine load and improve fuel economy. Such regulators are used on car generators such as Shanghai Buick and Guangzhou Honda. Operation and maintenance The regulator is generally not allowed to remove the cover during the operation. Normally, a comprehensive inspection and maintenance is performed every 200 hours of operation. The contents are as follows: 1) Remove the cover and check the contact surface for dirt and burning loss. If there is dirt, wipe the contact surface with a clean paper. If the contact is ablative or the surface is not flat and the contact is poor, generally use "00" sandpaper or sand strip to grind it, and then clean it with clean paper. 2) Check the fastness of each connector and measure the resistance and resistance value of each coil. If there is any damage, repair or replace new ones in time. 3) Check the closing voltage and reverse current of the current interrupter, the limiting voltage and the limiting current of the throttle, and the gap and air gap of various contacts. If it does not meet the requirements, it should be adjusted. 4) Check the adjusted regulator and pay attention to the indication of the charging ammeter pointer when starting the diesel engine. If the pointer of the ammeter is still pointing to the "-" side when the diesel engine operates at a moderate speed, it indicates that the contact of the current breaker is not disconnected, the earthing switch should be quickly disconnected; otherwise, the battery, regulator and charging generator will be damaged. If the pointer of the ammeter still points to "0" after the diesel engine starts to the rated speed, it shows that the adjustment is not adjusted according to the technical requirements, should be checked and adjusted again.
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While the diesel generator is running the load, it is also the process of mutual wear of the parts of the diesel generator itself. Starlight Power – Diesel Generator Manufacturer recommends that users minimize the wear between the components of the gensets. Reducing the wear of the parts is also a way to extend the service life of the unit. Here are some effective ways to reduce wear of the generator parts. The quality of the fuel and lubricant of the diesel generator set should be matched with corresponding specification of generating set. If diesel contains sulphur or other impurities, acid and other corrosive substances will be generated during the combustion process to accelerate the wear of the cylinder; too much heavy fraction in the diesel fuel will easily form carbon deposits after combustion, abrasive wear is generated between the piston ring and the cylinder; viscosity of the diesel has an effect on the formation of the mixture and the reliability of the oil supply equipment. For lubricating oil, the viscosity and oxidation resistance is the most influential. It should be reasonably selected according to the working conditions of the diesel generator set. Tests showed that the friction of diesel generators increases with the increasing of rotating speed and load. As the load increases, the unit pressure on the friction surface increases and the thermal condition is poor. When the rotational speed increases, the number of times of frictions is increased by half per unit time, and under the same power, the increase of rotational speed is greater than the load increases. However, too low rotating speed can not guarantee good liquid lubrication conditions, and also increases wear. Therefore, a suitable working speed range is required for the trouble-free operation of power generator. In addition, when the operation of diesel generator set is often unstable, such as acceleration, deceleration, stop and start, due to frequent changes in the speed and load, the lubrication condition of diesel genset is poor, the thermal state is unstable, and the wear is increased. Especially when starting, the crankshaft speed is low, the oil supply from oil pump is not in time, the oil temperature is low, the oil viscosity is large, and the friction surface is difficult to establish liquid lubrication, and the wear is very serious. Diesel generator set wear caused by ambient temperature Engine is easy to overheat when the temperature is high, the viscosity of the lubricating oil is low, and the wear of the parts is increased. When the temperature is low, the viscosity of the lubricating oil becomes large, and the diesel generator is difficult to start. The cooling water cannot maintain the normal temperature during operation, which increases the wear and corrosion of the parts. The wear is more serious when the gensets is at low temperature. The operating temperature of diesel generating set is one of the important factors affecting the wear. During the process of operating, due to the limitations of the cooling system structure, change in the workload and speed and the change in the ambient temperature, the operating temperature of the diesel generator set varies greatly. Practice shows that the cooling water temperature is controlled at 75-85°C, and the lubricating oil temperature is 75-95°C. To sum up, users should strengthen the technical study of diesel gensets to ensure the correct use of the units and reduce the wear of parts. The engineer of diesel generator manufacturer instructs everyone to proceed from the following aspects: 1. Reasonable choose the operating condition of the diesel generator. 2. Improve the running-in quality of diesel generators. 3. Select fuels and lubricants suitable for the working needs of diesel engines. Select suitable lubricant and lubrication method, replace dry friction with ideal fluid friction, which is the most effective way to reduce friction and wear. For generators, according to the specific requirements of different engine and the season and the use of different regions to choose the appropriate brand of lubricants. 4. Improve the level of operation technology and timely maintenance. During use, the maintenance of the fuel supply system, the intake system and the lubrication system should be done. No matter how good the quality of the product, only know how to better maintain, can reduce the wear of the products and extend the service life of the machine. Maintaining Cummins diesel generator set in Autumn: 1. Cleaning cooling system The cooling system must be cleaned in order to make it work properly. The scale in the system reduces the heat it absorbs from the water jacket and releases to the radiator using clean water to avoid blocking the radiator and hundreds of tiny waterways in the cylinder block. For radiator cores, heater cores, oil coolers and waterways in cylinder blocks blocked by scale and sediment, chemical cleaning agents are used to wash, neutralize and flush. In order to ensure the cooling system to work effectively, the DCA water filter is used to prevent rust and scale formation. If DCA is used, the cooling system must be chemically cleaned. Use a good cooling system cleaner, such as sodium bisulfate or oxalic acid, then neutralize and rinse. Flush radiators and cylinder blocks before adding antifreeze, or install water filters on used or overhauled engines. When flushing the radiator under pressure, open the upper and lower hose joints and tighten the radiator cap. The use of hose connections on the upper and lower water pipe joints can facilitate the operation. Connect the gun nozzle to the water pipe to fill the radiator. Then step by step increase the air pressure so as not to crack the radiator core. Stop the air intake, let the radiator fill up again, then add the pressure, so repeatedly, until the water out of the radiator becomes clear. Be careful not to use excessive air pressure when starting to drain water, so as not to crack the radiator core. Sediment and dirt, in addition to deposition in the radiator core, but also in the tank pit of the cylinder block. Remove the thermostat and flush the cylinder block with water. Close the bottom outlet until the cylinder is filled with water and apply air pressure to force the water to flow out from the bottom outlet. Cummins generator set coolant requirements: A. Use water filter or add DCA dry powder as required to prevent corrosion, cavitation and scaling of the cooling system. B. Check the seal of the water tank pressure cap and the leakage of cooling system to ensure that the boiling point of the coolant is not lowered and the cooling system is normal. 2. Check hose connections for oil filters and cooling systems for leakage and damage. Debris from damaged hoses entering the cooling system or lubricating system will limit or even block small waterways and oil coolers of radiator cores and partially stop circulation, so replace them if necessary. 3. Switches for automatic shutters and automatic fans should be adjusted to the temperature range of the thermostat switch used. Automatic shutters and automatic fans in general use, and thermostats with adjustment range of .821291 ℃ are only closed at 86 ℃, while automatic shutters open at 91 ℃ work together. 4. Remove the thermostat from the thermostat shell and check its switch temperature. Most Cummins engines are equipped with 77'85 ℃ medium temperature and 71'79 ℃ low temperature thermostats, and in a few cases 8291 ℃ high temperature thermostats due to engine use. Maintaining Cummins diesel generator set in Spring: 1. Use steam to clean the engine Steam cleaning is the most effective way to clean dirty engines or equipment. If there is no steam, use the prescribed solvent to clean the engine. Avoid the impact of the full force of the flushing nozzle, to protect all electrical components and wires. 2. Fasten mounting bolts and nuts Engine mounting bolts are occasionally loosened so that engine hangers and supports wear out quickly. Tighten all mounting bolts and nuts, damaged replacement, missing replacement. 3. Fastening turbocharger mounting nut Tighten all supercharger mounting bolts and nuts and make sure they are really tight. Tight mounting bolts and supports minimize vibration. 4. Check the installation of fans and pulleys Check if the fan is firmly installed, tighten the fastening bolt when necessary. Check if the fan is swaying or the blade is bent. Check if the fan hub and crankshaft belt are securely installed. Check if the fan hub pulley is loose and swaying. Remove the fan separator to tighten the shaft nut if necessary. Tighten the fan support bolt. 5. Check the crankshaft end gap The crankshaft end clearance of the new or overhauled engine shall comply with the relevant regulations. A worn engine whose end gap exceeds the wear limit cannot be used. If the engine is taken apart for repair, a new thrust ring is fitted. The way to check the end gap is to have an end gap when the engine is installed with a transmission or torsion when the end face of the dial damper or leather wheel is installed on the generator set. 6. Check the zinc plug of heat exchanger Check the zinc plug of the heat exchanger and replace it if it is seriously corroded. The frequency of replacement depends on the chemical reaction of the circulating raw water in the heat exchanger. Every diesel generator can not start without a battery, and the sufficient power of the battery is a necessary condition to ensure the success of the diesel generator. So how does the battery flush is correct? Note: 1. Ensure that batteries are charged in a well-ventilated environment without sparks and open fires. Do not charge in an environment without wind and snow, do not charge near water. Remember to cut off the charger before removing the connector. Static (municipal) chargers can be used to charge batteries, which should be disconnected from the connection of the generator set and charged with an external charger. Charger and battery connection: charger should be connected to a suitable electricity, plug the following connection. Joint connection: battle line Line 6 central line line N1 earth wire Green / yellow line Batteries should be connected in the following ways: Battery connection method: Positive terminal(+) redline negative (-) electrode Terminal line black The connection battery and charger can be connected as follows Operation of charger: after the charger is connected to electricity, and the charger is connected to the battery, the charging steps are as follows: the electrolyte filter cap or exhaust hole cover is unplugged during the charging process. Check electrolyte water level and adjust it with distilled water when needed. Turn on the charger and observe the normal charge rate, which is determined by the battery capacity, depending on the new and old conditions of the battery and the current charging level. After charging begins, the charging current decreases and continues to decrease as the current voltage increases. The specific gravity of each battery solution is then measured by hydrometer. Do not overcharge the battery, otherwise it will damage the battery. High temperature can also damage the battery, be careful during charging, especially in the hot climate, the battery temperature must not be higher than 45 degrees. Note: when repairing and maintaining the starting battery of diesel generator set, wear acid-proof apron and face mask or protective goggles. Once the electrolyte splashes on the skin or clothing, rinse with plenty of water immediately. Injection of electrolyte: Batteries are often dry in transit, so add the correct mix of specific gravity electrolytes. Remove the plug and pour into each cell until 8 mm above the top edge of the sheet, leaving the battery on for 15 minutes. Check and adjust the water level if necessary. First charge: The battery must be recharged for 4 hours within an hour of injection, with the following current, which allows the battery to be fully mixed, such as insufficient charging time can damage the capacity of the battery. The charging current of the battery model E017 is 9AMPs, and the charging current of E312 is 14AMPSU E324, the charging current is 20AMPS. The above 4 hours of charging may be extended as follows: Battery storage for more than 3 months, or temperature over 30 degrees or higher than BO% for 8 hours Battery storage time over 12 hours a year. If the current output of the charger is not enough, then the lower current can be achieved, but not less than one third of the above, but the time is lengthened proportionally. (8 hours 7AMPs instead of 4 hours 14AMPs). At the end of the charging time, the electrolyte water level should be checked. If it is necessary to add the proper proportion of sulfite electrolyte, the exhaust plug will be put back to its original position. Normal operation and charging can cause some water to evaporate, which requires the battery to be liquid from time to time. First clean the battery to avoid falling into the dirt, and then remove the exhaust plug. Add distilled water until 8MM (5 / 16) returns to the exhaust plug. Storage battery is the key to open diesel generator set. In order to ensure fast and reliable start of diesel generator set, battery maintenance must be done well. In the daily use of diesel generators, a very common fault is that the diesel generators cannot start normally, and most of the reasons for the failure of the diesel generator are the failure of the battery. Below are instructions used to solve the diesel generator battery failure and repair program. fault phenomenon repair Uncharged current Wrong or ice dragon is not good Clean terminal connector Low voltage for used or used batteries Battery replacement or special equipment charging No electricity voltage Check the lines from electricity to charger Power fuse failure Change fuse Rectifier secondary transistor fault Replacement rectifier diode fault Charge ammeter not shown Rechargeable ammeter failure Replace charged ammeter Filling rate is too low Low voltage Check charging power supply Incorrect transformer tap Check if the current voltage is equal to the transformer tap Large current joint loose Check and tighten the tap Charging clip heating Poor battery connection Clean tap to be attached Repeated fire destruction of fuse on power supply Fuse power failure Put on a suitable fuse short circuit Check, reconnect all the lines. Charge current does not decrease Battery aging damage Charger is not a fault, battery voltage can not rise to the maximum voltage Power distribution cabinet is an indispensable part of diesel generator set. During the operation of the diesel genset, it is inevitable that it will cause certain wear and tear to the distribution cabinet. In order to make the life cycle of the distribution cabinet of the generator set last for a long time, it is necessary and important to do maintenance to the distribution cabinet. Gen Set Power Distribution Cabinet Maintenance - Preparation 1. When doing maintenance to the distribution cabinet, inform customers in advance of power outage. 2. Do all the preparation work before the power outage, especially the preparation tools of the genset should be complete. 3. Unified command by project manager, the personnel participating in the maintenance work are unified in action, and the division of labor is reasonable, so that the work can be completed efficiently. Gen Set Distribution Box Maintenance – Power failure 1. Disconnect the automatic air switch of the diesel generator, put the selection switch in “Stop” position, disassemble the positive and negative line of the battery, and hang the warning sign to prevent the generator from transmitting electricity. 2. Disconnect the low-voltage side air switch step by step, then disconnect the load switch on the high-voltage side of the transformer. After confirming the disconnection position, close the ground switch, then lock the high-voltage cabinet with the lock, and hang the sign of "someone is operating, no closing". 3. Open the door of the distribution cabinet and check the low voltage busbar in the power outage state with the test pencil. Check if there is any deformation at the busbar joint, whether there is any blackening of the discharge, and tighten the coupling bolts. If the bolt is rusted, it should be replaced to ensure that the joint is tightly connected. Check the insulators on the busbar for looseness and damage. 4. Use the handle to shake the total air switch out of the power distribution cabinet, check whether the main contact has the mark of burning and melting, check whether the arc extinguishing cover is burned black and damaged, tighten the wiring screws, clean the dust inside the cabinet, and test the machine closing and opening situation. 5. Take out the sub-switch cabinets from the drawer cabinet, check and tighten the terminals of the current transformer, ammeter and watt-hour meter. Wiring, check the flexible reliability of the handle operating mechanism, tighten the air switch in and out line, and clean the dust in the switchgear and the outgoing line behind the power distribution cabinet. 6. When maintaining the capacitor cabinet, first disconnect the main switch of the capacitor cabinet, discharge the capacitor one by one with the wire of 25mm or more, then check and tighten the wiring screws of the contactor, reactor, and capacitor, whether the grounding device is good, check the capacitor for bloating and use a vacuum cleaner to clean the dust in the cabinet. After the maintenance is completed, clean the tools and evacuate the site. A 500V megger is used to measure the insulation resistance of the busbar to the busbar and the busbar to the ground above 0.5M. Gen Set Distribution Cabinet Maintenance – Trail Operation 1. Disconnect the earthing switch on the high voltage side of the transformer, confirm the disconnection position, close the load switch on the high voltage side of the transformer, observe whether the no-load operation of the diesel generator set transformer is normal, then lock the high voltage switch cabinet with the lock and remove the sign. Close the low-voltage side air switch step by step and check if the low-voltage power distribution cabinet is working properly. Attention 1. Power should be checked after power failure. 2. When the power distribution cabinet is maintained in sections, an isolation device shall be installed at the junction of the live and unpowered distribution cabinets. 3. When operating the high-voltage side vacuum circuit breaker, should wear insulation boots, wear insulated gloves, and have special personnel to monitor. 4. When maintaining the capacitor cabinet, it is strictly forbidden to touch before the capacitor is discharged to the ground. 5. Before power transmission after maintenance, check if there are any tools left in the power distribution cabinet. Distribution Cabinet Operation Procedures 1. The power distribution cabinet is the normal operation of the ship's power distribution center and the equipment, and any unrelated personnel shall not pull the switch on the board. 2. After the generator set is started, the power screen speed up switch should be used to accelerate the generator manually and slowly until the generator enters the normal working state, and the voltage and frequency reach the specified value before closing for power transmission. 3. After the switchboard enters the power distribution state, it is not allowed to unplug the power panel speed-up switch at will. The lock switch of the air circuit breaker shall not be used in non-emergency situations. 4. Parallel operation of generators must be carried out strictly accordance with the requirements and regulations of the parallel operation conditions. It is necessary to pay attention to the phenomenon of reverse power (countercurrent) and failure of the parallel operation. 5. When stopping the machine, the generator load should be cut off first, then stop without load, and no direct shutdown should be carried out with load. 6. When interleaving the shore electricity, the power switches of the shore power screen should be cut off first, and then the correctness of the wiring and phase sequence should be checked. After confirming the correctness, the conversion of the ship shore power can be implemented, and the operation with load is strictly prohibited. 7. The power distribution cabinet should be cleaned and maintained regularly to keep the equipment in good working condition. 8. When the generator is working, the turbine personnel should concentrate on thinking and carefully operate the switchboard to prevent accidents, otherwise the individual accident liability will be investigated. 9. The charging and discharging board is the ship emergency power distribution board. The engineers on duty should check its working condition at any time to ensure the low voltage power is sufficient and master the working condition of the magnetic saturation voltage regulator through the instrument on the board. 10. During normal navigation, the switches on the switchboard should be turned on to ensure that the generator can be started at any time and ready for use. On November 21, 2018, Gu Xiaoxing, General Manager of Starlight company and Wang Lu, General Manager of Starlight Guangxi Branch Office participated in the first handover ceremony of China's first largest power gas generator developed by Yuchai Group on behalf of Jiangsu Starlight Electricity Equipment Co.,Ltd. The 450,000th units engines and 30,000th units marine power off-line ceremony of Yuchai Group was held in the large marine electrical assembly workshop of Yuchai Marine Electric Power Division. The off-line 30,000th marine electric power is also China’s first 1500kW high-speed large-bore power generation gas engine - YC12VCN. All the staff of Yuchai Group and the guests and friends attending the ceremony gathered together to commemorate this historic moment. Yuchai is the leading state-level enterprise technology research and development center in the internal combustion engine industry. And it is also the first domestic company launching the micro-sedan diesel engine with independent intellectual property rights to fill the gap in the domestic industry. Currently, Yuchai boasts 400,000 units engines in operation in the overseas market. So far, it has made its presence in over 180 countries and regions across the globe. In recent years, it has made particularly impressive breakthrough in European and US market. Since 2013, Yuchai has planned and implemented the strategy of promoting the second venture, transformation and upgrading, adhering to the enterprise development policy of making specific efforts to strengthen and increase the size of the enterprise, with excellent power and comprehensive marketing service advantages. Outstanding achievements has been made in the market segments of trucks, passenger cars, construction machinery, agricultural machinery, marine power and power generation. In just a few years, Yuchai's high-power marine and power generation engines market share has leapt to the first place in the industry. Since 2014, Yuchai has carried out a comprehensive reform on the business segment of high-power marine and power generation engines from management mode, marketing channel, research and development system, production and procurement system, etc., and timely delivered YC6CA and YC8CL and YC12VC new products in response to market changes. The New products have been highly recognized by users, broke the monopoly of competitive products, made a major market breakthrough, and achieved a sales growth of over 30% for three consecutive years from 2015 to 2017. The off-line YC12VCN is a large bore gas engine for power generation independently developed by Yuchai. Rated power is 1500kW. Emissions meet the European TA-luft standard. Compared with similar domestic models, power density is more than 20%, gas consumption is 10% lower, and weight is 12% lighter. This model adopts high-efficiency supercharge pre-mixing and lean combustion technology. It has the characteristics of low gas consumption, low emissions and high reliability. It is currently the first largest gas engine in China. It is mainly used for 1200kW common gensets, which is used in oil exploitation, natural gas exploitation and livestock breeding industry (biogas engineering) and waste disposal industry and other fields. The fuel is natural gas, biogas, biomass gas and so on. Witnessed by Yuchai Stock President Wu Qiwei and other company leaders, Ning Xingyong (Right), secretary of the Yuchai Stock Party Committee and executive vice president, handed over the key to the order delivery to customer representative Gu Xiaoxing (Left), General Manager of Jiangsu Starlight. Jiangsu Starlight Electricity Equipment Co., Ltd., as Yuchai's largest OEM main engine supporting factory, has more than 40 years experience in diesel generator setsproduction. The company has perfect testing equipment, fine production technology, professional manufacturing technology, perfect quality management system, and exquisite research and development technology, 46 sales service departments all over the country, providing design, supply, commissioning and maintenance one-stop service for customers at any time. The operating temperature of diesel generator has a clear allowable range. If it exceeds or falls below the allowable temperature range, the diesel generator may be damaged and even cause accidents. There are many reasons for the overheating of diesel generators. 1. The diesel generator does not operate in accordance with the prescribed technical conditions, such as too high stator voltage, increased iron loss, too large load current, increased copper loss in stator winding, too low frequency, which will slow down the speed of cooling fan and affect the heat dissipation of generator, and the power factor is too low. It will increase the rotor excitation current and then cause the rotor to heat. Users should check that the monitoring instrument's instructions are correct. If the monitor is abnormal, must carry on the necessary adjustment and the processing, causes the generator to operate according to the stipulated technical condition. 2. The three-phase load current of the diesel generator is unbalanced, and the over-loaded one-phase winding will overheat. If the difference of the three-phase current exceeds the rated current by 10 percent, it is a serious phase current imbalance, and the three-phase current imbalance will produce a negative sequence magnetic field, thus increasing the loss. Causes the magnetic pole winding and hoop and other parts to heat. The three-phase load should be adjusted to keep the current balance as far as possible. 3. The air duct is blocked by dust and the air is not well ventilated, which makes it difficult for the diesel generator to dissipate heat. 4. If the inlet air temperature is too high or the inlet water temperature is too high, the cooler will be blocked. The inlet or inlet temperature should be lowered to remove the clogging in the cooler. Before the fault is eliminated, the generator load should be limited to reduce the generator temperature. 5. Bearings with too much or too little grease should be added as prescribed, usually 1 / 2 / 1 / 3 of the bearing chamber (upper limit of low speed and lower limit of high speed), and should not exceed 70% of the bearing room. 6. Bearing wear. If the wear is not serious, the bearing will overheat locally, and if the wear is serious, the stator and rotor may be friction, which will cause the stator and rotor to overheat. Bearings should be checked for noise, if any stator and rotor friction, should immediately stop for repair or replacement of bearings. The noise of diesel generator mainly comes from diesel engine and generator. In order to reduce the noise of generator set, the main noise source should be controlled, and the key to the control is to find the main sound source accurately. I Main noise sources of Diesel engines 1. Intake and exhaust noise Intake and exhaust noise is the strongest noise source of diesel engine. The intake noise is mainly the pressure pulsation of air in the intake pipe, the low frequency noise, the high frequency eddy current noise produced by the air flowing through the inlet valve section at high speed, and the noise of the turbocharger compressor of the turbocharged diesel engine. The exhaust noise is mainly the pressure pulsation of exhaust gas in the exhaust pipe, which produces low and medium frequency noise, and the high frequency eddy current noise at the flow section of the exhaust valve. 2. burner noise The combustion of combustible mixture in cylinder causes the rapid change of gas pressure, which causes the piston, cylinder head, connecting rod, piston pin, crankshaft and other parts to be subjected to impact load, resulting in structural vibration and noise. 3. mechanical noise Due to the periodic changes and impact of the forces between the parts of the diesel engine, the surface vibration produces noise. The mechanical noise increases rapidly with the speed of the engine. The main parts of the mechanical noise are piston, cylinder head, cylinder block, cylinder liner, connecting rod, piston pin, crankshaft, valve train, gear, spray. The design of the components, the quality of the manufacturing and the selection of materials have an important effect on the noise. The structural stiffness of the diesel engine, the speed of the engine and the clearance of the moving parts are the main factors affecting the mechanical noise. II Main noise sources of generators 1. ventilation noise Electromagnetic noise is caused by the interaction of stator and rotor magnetic field in the air gap of generator to produce radial force varying with time and space, which causes the stator core and seat to deform periodically and cause vibration and noise.
Electromagnetic noise is caused by the interaction of stator and rotor magnetic field in the air gap of generator to produce radial force varying with time and space, which causes the stator core and seat to deform periodically and cause vibration and noise. 3. mechanical noise The mechanical noise of generator includes mechanical vibration and noise caused by centrifugal force caused by rotor mechanical imbalance, vibration noise of bearing, sliding contact noise of brush collector ring or commutator, axial vibration noise of end cover excited by bearing vibration. As a field power source and emergency power reserve, diesel generator sets are widely used in industrial and agricultural production, national defense, science and technology and daily life. So as a diesel generator distributor or dealer, how can we buy a satisfactory diesel generator? Starlight power technology teaches you how to judge and measure the performance of diesel generators from a professional point of view so as to buy products with high cost performance. Economic indicators The economic indicator generally refers to the fuel consumption rate and the lubricating oil consumption rate of the diesel engine. Fuel consumption rate Fuel consumption rate, it is the diesel engine per kilowatt-hour consumption of fuel A in g / (kWh). The fuel consumption rate per kilowatt-hour in an indicator power meter is called the indicative fuel consumption rate, and the fuel consumption rate per kilowatt hour in an effective power meter is called the effective fuel consumption rate. The former indicates the indicator of diesel engine economy. The latter indicates the economic efficiency of a certain engine. The fuel consumption rate referred to in the diesel engine product description refers to the effective fuel consumption rate. The fuel consumption rate referred to in the diesel engine product description refers to the effective fuel consumption rate. After measuring torque me and rotational speed n, as well as fuel consumption per hour TGT (kg/h) and effective power Pe, the effective fuel consumption rate ge is obtained by the following formula. ge=Gt/Pe*10^3[g/(kW.h)] The range of ge [g / (kW.h)] for diesel engines is as follows: High speed diesel engine ge=212~235 Low-speed diesel ge=169~190 lubricating oil consumption The consumption of oil consumption per kilowatt-hour in a diesel engine is called the skid consumption rate in g / (kW h). The g number of oil consumption per kilowatt-hour in a diesel engine is called the skid consumption rate in g / (kW h). Diesel engine lubricating oil is used continuously in the engine, the main reasons for its consumption are: when the diesel engine is in operation, the lubricating oil enters the combustion chamber through the piston or is burned by the air valve pipe flow in the gas cylinder, and the unburned oil is discharged with the exhaust gas. In addition, a portion of the lubricating oil due to atomization or evaporation in the crankcase by the crankcase vent. Diesel engine oil consumption rate is generally 0. 0. 5-4g/ (kW.h). Dynamic performance index The power performance index refers to the external work capacity of diesel engine, generally refers to the power, the average effective pressure, the rotational speed and the piston average speed and so on. active power The unit of power of a diesel engine in a unit of time is 1 kW 1 000 N ·m / s. The work done by a diesel engine per unit time in the cylinder is called indicated power. The power extracted from the engine crankshaft is called effective power after the indicated power is subtracted from the friction loss of the internal parts, the mechanical loss of power such as the pump air torsion loss and the driving accessory loss is subtracted from the engine crankshaft. If the crankshaft speed per minute is n and the crankshaft output effective power per second is We. the effective power of diesel generator is Pe=PI*nMe/30000(kW) Me is effective torque Speed and average Piston Velocity Speed diesel engine crankshaft per minute speed, expressed by r/min. The speed has great influence on the performance and structure of diesel engine, and its range is very wide. Various types of diesel engine speed range is different. The average speed of the piston cm is constantly changing in the cylinder, which is larger in the middle of the stroke, smaller in the vicinity of the stop point, and zero at the stop point. If the engine speed n is known, the piston average speed can be calculated by the lower formula. Cm=2*Sn/60=Sn/30(m/s) Mean Effective Pressure The average effective pressure of eight is usually used to compare and evaluate the dynamic performance of various engines. It is a hypothetical pressure acting on the top of the piston, and it is the work done by the piston to move a stroke, equal to the effective work done per cycle. Pe=i*Vs*Pe*n/30t(kW) i—number of cylinders ; Vs-stroke capacity,L; Pe—mean effective pressure ,MPa; n —engine speed,r/min ; t 一Stroke number of engine So, Pe=30*t*Pe/i*Vs*n It can be seen that Pe represents the effective power per unit cylinder working volume .Pe is an important index, which not only indicates the working cycle is good or bad, but also includes the size of mechanical loss, the higher the value of Pe is under the same conditions, The more effective work the engine outputs. The values of Pe are generally as follows: Non-turbocharged diesel engine is (0. 5—O.9)MPa Turbocharged diesel engine is (0. 8—3.2)MPa Exhaust pollution index There is a small but very harmful amount of emissions in the exhaust of a diesel engine. They are carbon monoxide CO, hydrocarbon HC, nitrogen oxide NO, and sulfur dioxide SO2. These combustion products pollute the environment and are harmful to human health, resulting in social pollution. With the enhancement of environmental protection consciousness, the restriction of diesel engine exhaust pollution is becoming more and more strict. China's national standards (GB 267-87) have imposed no 2 limits on diesel engine emissions as follows: When Pe>300kPa,ge《214g/(kW·h),NOx is limited at 29g/(kW .h); When g=214-268g/(kW .h),NOx is limited at 14-25g(kW·h); When ge>268g/(kW·h),NOx is limited at llg/(kW·h)。 Weight and shape dimension index The weight and shape size of diesel engine is an index to evaluate the structure compactness and metal material utilization ratio of diesel engine. Different types of diesel engines require different weights and dimensions. Weight index The weight index of a diesel engine is usually measured in terms of its specific mass. Specific mass (gw), also known as unit power mass, is the ratio of the net weight of diesel engine Gw to the calibrated power Pe. gw=Gw/Pe(kg/kW) The so-called net weight refers to the quality of the auxiliary equipment and auxiliary systems which do not include fuel oil, lubricating oil, cooling water and other auxiliary systems not directly installed on the internal combustion engine body. The specific mass is related not only to the type of diesel engine, the structure, the size of accessories, but also to the materials used and manufacturing technology. Shape dimension index Shape dimension index, also called compactness index, is the index of compact degree of overall arrangement of diesel engine. It is usually measured by the unit volume power of a diesel engine. The unit volume power Pv is the ratio between the calibration power Pe of the diesel engine and the external volume V of the diesel engine. Pv=Pe/V (kW/m^3) V=LBH Among them, L, B, H is the maximum length, width and high size of diesel engine. Generator sets have been widely used in banks, schools, airports, hospitals, real estate and other fields, but many users lack understanding of generator sets. In order to enhance the understanding of generators for users, the following explains the permanent magnet generators and excitation. The difference between generators. The generator can be divided into a permanent magnet generator and an excitation generator. The biggest difference between the permanent magnet generator and the excitation generator is that its excitation magnetic field is generated by a permanent magnet. The permanent magnet is both a magnetic source and a component of the magnetic circuit in the motor. The excitation power unit provides the excitation current to the rotor of the synchronous generator, and the excitation regulator controls the output permanent magnet generator of the excitation power unit according to the input signal and the given regulation criterion. The excitation power unit supplies an excitation current to the synchronous generator rotor; and the excitation regulator controls the output of the excitation power unit based on the input signal and a given adjustment criterion. The automatic excitation regulator of the excitation system plays a considerable role in improving the stability of the parallel unit of the power system. In particular, the development of modern power systems has led to a trend of lowering the stability limit of the unit, and has also led to the continuous development of excitation technology. The excitation system of the synchronous generator is mainly composed of two parts: a power unit and a regulator (device). The excitation power unit is a portion of the excitation power source that supplies a DC excitation current to the rotor winding of the synchronous generator, and the excitation regulator controls the output of the excitation power unit according to an input signal required by the control and a given adjustment criterion. The entire system consisting of the excitation regulator, the excitation power unit and the generator itself is called the excitation system control system. The excitation system is an important part of the generator, which has a great impact on the safe and stable operation of the power system and the generator itself. The main functions of excitation system are: 1. Improving the static stability of generator in parallel operation. 2. Improving transient stability of generators in parallel operation. 3. Reactive power distribution among generators in parallel operation. 4. When there is a fault inside the generator, de-excitation is carried out to reduce the degree of the fault loss. 5. Maximum excitation limit and minimum excitation limit for generators according to operation requirements. 6. The excitation current should be adjusted accordingly according to the change of generator load, and the voltage at the terminal of the generator should be maintained as the given value. 1. Excitation mode of DC generator power supply The generator with this excitation mode has a special DC generator, which is called a DC exciter. The exciter is coaxial with the generator. The excitation windings of the generator obtain DC current from the exciter through the sliding ring mounted on the big shaft and the fixed brush. This excitation mode has the advantages of independent excitation current, reliable operation and reducing self-consumption of electricity. It is the main excitation mode of generator in the past few decades, and has more mature operation experience. The drawback is that the speed of excitation regulation is slow and the maintenance work is large, so it is seldom used in units above 10MW. 2. Excitation mode of AC exciter power supply Some modern large-capacity generators use AC exciter to provide excitation current. The AC exciter is also installed on the generator shaft, and the output AC current is rectified to supply the generator rotor excitation. At this time, the excitation mode of the generator belongs to his excitation mode, and because of the use of static rectifier, it is also called the static excitation, and the AC auxiliary exciter provides the excitation current. AC auxiliary exciters can be permanent magnetic machines or alternators with self-excited constant voltage devices. In order to improve the speed of excitation regulation, the AC exciter usually adopts the generator of 100-200HZ, while the AC sub exciter adopts the generator of 400-500HZ. The DC excitation winding and the three phase AC winding of the generator are wrapped in the stator slot. The rotor has only teeth and slots and no winding, like a gear. Therefore, it has the advantage of reliable operation, simple structure and convenient manufacturing process. The drawback is that the noise is high and the harmonic component of the AC potential is larger. Self-excited excitation system of generator can be divided into several forms. The excitation system with excitation power supplied by the generator itself is called self-excited excitation system. The AC exciter is a rotating machine in the excitation system, while in the self-excited excitation system, the excitation transformer and rectifier are all static components, so the self-excited excitation system is also called the all-static excitation system. Self- excited excitation system can be divided into the following forms. 1. Self-shunt excitation system Self excitation sstem, self-shunt excitation system, which obtains excitation power from synchronous generator voltage. As shown in figure 1, the wiring diagram of the self-shunt excitation system. Alternator current from a synchronous generator is converted to the required voltage by an excitation transformer (some low-voltage small capacity units are introduced directly from the machine end). from thyristor or power diode rectifier to DC, supply excitation winding to establish magnetic field. Automatic regulator automatically adjusts excitation current according to generator output voltage variation. 2. Self-excitation system The self excitation system, which obtains excitation power by both voltage and current of synchronous generator, is called self compound excitation system. According to the excitation current compound position, there are DC side recombination mode and AC side compound mode. Medium and small capacity diesel generator sets are mainly AC side parallel complex uncontrollable excitation system, as shown in figure 2. The excitation transformer is connected in series with a reactor and connected in parallel with the excitation converter. The output of the excitation transformer is superposed and then rectified by a silicon rectifier to supply the excitation of the synchronous generator. The excitation transformer is connected in series with a reactor and connected in parallel with the excitation converter. The output of the excitation transformer is superposed and then rectified by a silicon rectifier to supply the excitation of the synchronous generator. This excitation system can reflect the voltage, current and power factor of generator, also called uncontrollable phase compound excitation system. Diesel Generator Set Circulating Cooling System The cooling system of the diesel generator set is forced liquid cooling, or pressure liquid cooling, that is, the diesel generator set has a dedicated cooling water pump to complete the circulating flow of the diesel generator coolant. According to the conditions of use of the diesel generator set, open cycle cooling or closed cycle cooling may be employed. Let's share the working principle of the open-circuit cooling system of the diesel generator set. The open-type circulating cooling system, that is, the inlet and outlet of the diesel generator set is open, and the user directly turns on the water source during use. Depending on the layout of the diesel generator set and the oil cooler, the types of open-circuit circulating cooling systems are slightly different. When the diesel generator set is working, the inlet water temperature is required to be not lower than 60 °C. Therefore, appropriate measures should be taken to adjust the appropriate inlet water temperature for the water used in the open-loop cooling system. Generally, a mixing bucket can be installed between the water source and the diesel generator set, and the inlet and outlet of the diesel generator set and the water from the water source can be connected to the mixing bucket, and the diesel generator set can be controlled by controlling the amount of cold water entering the mixing bucket. Inlet temperature. Diesel generator sets are not allowed to have air resistance and water cut during operation, especially when the diesel generator set is parked for a long time, it is more prone to waterway air resistance. Because the gas resistance or water cut will cause the diesel generator set to overheat, and even serious accidents such as pulling the cylinder, it should be promptly removed. If there is air resistance: the water volume of the cylinder head outlet pipe is reduced or the water is not discharged at all, the reading of the water temperature meter rises sharply. At this time, do not stop the emergency. The load should be appropriately reduced, the rotation speed should be reduced, and the water temperature at the outlet end of the cylinder head should be quickly released. The susceptor releases the air in the waterway until the cooling water flows out and the water temperature returns to normal. Be careful when deflated to prevent heat from injuring people. The difference between small cycle and large cycle of diesel generator set During the operation of diesel generator sets, there are often cases where the coolant does not circulate, including large cycles, no small cycles, or small cycles without large cycles, resulting in a rapid rise in cylinder temperature and an increase in oil temperature. The sudden shutdown and other phenomena directly affect the safe use of diesel generator sets. So what is the small cycle and large cycle of the diesel generator set? The difference between small cycle and large cycle of diesel generator set Diesel generator set small cycle When the temperature of the cooling water of the engine is lower than the opening temperature of the thermostat, the thermostat is in a closed state, and the cooling water of the engine outlet flows back into the water jacket of the cylinder block through the water pump for small circulation. Diesel generator set big cycle When the cooling water temperature reaches the set value or above (different engines have different requirements for the opening temperature of the thermostat), in order to control the engine cooling water within the specified temperature, the thermostat is opened and the cooling water of the engine outlet is opened. It flows to the radiator for cooling and then flows into the engine cooling channel via the pump. Analyze the cause of the generator coolant not circulating The non-circulation of the generator coolant has a great impact on the operation of the equipment. Today, the Guangxi Guangxi technicians will teach you how to judge the reason why the coolant does not circulate. 1. Diesel generator pump failure. First of all, we must first check whether the pump is working well. If it is found that the pump drive pinion wears too much, the pump has no effect and needs to be replaced before it can be cycled normally. 2. The coolant level of the diesel generator set is too low or does not meet the requirements. If the liquid level is too low, the temperature of the coolant will increase directly, so that the coolant will not circulate. The coolant is 50% antifreeze + 50% softened water + DCA4 according to the regulations. If it does not meet the requirements, the pipeline will be blocked and the pipe wall will be produced. Rust prevents the coolant from circulating properly. 3. The diesel generator set thermostat is faulty. A thermostat is installed in the combustion chamber of the engine to control the temperature of the engine combustion chamber. The thermostat must be fully opened at the specified temperature to facilitate small circulation. If there is no thermostat, the coolant cannot maintain the circulating temperature, and a low temperature alarm may occur. 4. The air in the cooling system of the diesel generator set is mixed, which causes the pipeline to be unobstructed. The damage of the suction valve and the exhaust valve on the expansion tank directly affects the circulation. At this time, it should be checked frequently whether the pressure value meets the requirements. The suction pressure is 10kpa. The exhaust pressure is 40kpa. Except for the exhaust pipe, it is also an important reason for the circulation. 5. The radiator of the diesel generator set is blocked or damaged. The cooling fan does not work or the heat sink is clogged, so that the temperature of the coolant can not be lowered, and the heat sink is rusted, causing liquid leakage, which can also cause poor circulation. |
作者
dieselgenerator 存档
July 2022
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