When the AC synchronous generator operates, a DC excitation current flows through the rotor winding, which will produce what is called "copper loss" although the magnetic flux through the rotor core either CC, it moves relative to the stator core; , and the stator core will produce “iron loss”; if the stator winding is charged with AC electromotive force after induction, the current will flow through the stator winding, and the stator winding will also produce "copper loss"; into the rotor shaft and rotating parts, and “friction loss” will occur. All losses will appear as heat, which will increase the temperature inside the motor, especially in the rotor part, where the heat dissipation conditions are worse than other components.
Usually, the stator and rotor windings of generators are made of materials of cinsulated copper or copper wires with a certain level of insulation. Depending on the insulation material, the insulation level has certain limits on the maximum temperature allowed for its operation (such as Class B insulation, which is 130 degrees Celsius). If the temperature exceeds the specified value, the performance of the insulation material will deteriorate, accelerate the aging of the insulation, and eventually cause the insulation to break and burn.
To summarize, when the generator is working, the internal temperature will increase due to various losses, especially the rotor temperature, which will affect the insulation performance of the generator insulation material to ensure. than the generator For normal and reliable operation, the temperature of the generator rotor must be measured. If the measured temperature value exceeds the normal value, the monitoring equipment will issue an alarm to remind the reresponsible for paying attention to checking and eliminating possible faults, or reducing the power of the generator, or increasing the cooling of the generator. Eventually, the temperature of the generator rotor is reduced. Return to normal numbers to ensure safe and reliable generator operation.
The main reason why the exhaust temperature of the 500 kW generator set is too high
Motor insulation level: A, E, B, F , H. The insulation level of the motor is divided into A, there are 5 levels: E, B, F and H. The heat resistance degrees of the insulation materials used are divided into A, E, B degrees , F and H. Allowable temperature rise refers to the limit of the increase in motor temperature relative to the ambient temperature. The level of motor insulation is closely related to the insulating material used. The better the insulating material, the higher the level of insulation.
On timeCurrently, high-quality H-class water-based insulating paint insulation material 9019W is often used for impregnated insulation and moisture-proof treatment in high- and low-voltage high-speed and variable-frequency motors , air-conditioning of motors, transformers and inductance coils of electrical appliances.
Detailed informationPeople have stipulated 7 maximum allowable temperatures for different insulating materials based on their ability to withstand high temperatures. They are arranged according to temperature: Y, A, E, B, F, H and C. . Their admissible working temperatures are: 90, 105, 120, 130, 155, 180 and above 180°C.
Therefore, Class B insulation indicates that the heat resistance temperature of the insulation used by the generator (motor) is 130°C. When the generator is working, the user must ensure that the insulating materialt of the generator does not exceed this temperature to guarantee normal operation of the generator.
Baidu Encyclopedia-Motor Insulation Level
What are the effects of too high a generator inlet air temperature?
①The exhaust valve of the diesel generator set is not closed tightly;
②The fuel supply advance angle is too late;
p>< p>③The diesel generator is overloaded. According to the working conditions, the diesel generator set was found not to work under overload conditions and the valve clearances were checked to be within the specified range. Finally, it was found that the advance angle of the fuel supply of the diesel generator set was found. It was too late. After readjusting the fuel feed advance angle, the fault disappeared. This is also what causes early damage to the turbocharger.1) When the temperature is low, the combustion conditions of diesel in the cylinder deteriorate, the fuel atomization is poor, the combustion period after ignition is prolonged, and the engine is prone to rough operation , which aggravates damage to crankshaft bearings, piston rings and other parts, and reduces power economy.
2) Water vapor after combustion easily condenses on the cylinder wall, causing metal corrosion.
3) Diesel combustion can dilute engine oil and worsen lubrication conditions.
4) The fuel is not completely burned and forms a colloid, causing the piston ring to become stuck in the piston ring groove, the valve to become stuck, and the internal force of the piston to decrease. cylinder at the end of compression.
5) The water temperature is too low and the engine oil temperature is too low. The word oileur becomes thicker and the fluidity becomes poor. The amount of oil pumped by the oil pump is low, resulting in insufficient oil. power supply to the generator. In addition, the crankshaft bearing clearance becomes smaller and lubrication is reduced. Many operators do not want diesel generators to operate at operating speeds. They believe that lower speeds will not cause a breakdown. In fact, too low a speed will also cause bad consequences, as follows:
1) Too low a speed will reduce the power output of the diesel engine and reduce its power;
2 ) Too low rotation speed will cause the working speed of each component to decrease, which will deteriorate the working performance of the components, reduce the output pressure of the oil pump, etc. ;
3) Reduce the reserve power of the diesel engine, which must be runningnally normal. The diesel engine is under full load or overload.
4) If the speed is too low, the speed of the engine working machines; the linkage mechanism will also be reduced, which will reduce the mechanical performance of the work, such as reducing the water flow of the water pump, reducing the water pump. The elevator, etc.
Hello (Yizhong Power Plant) will answer for you:
If the generator wind temperature is too high, the stator coil temperature, the core temperature of iron and the rotor temperature will increase accordingly, causing insulation to appear. Weakening and weakening of mechanical strength will significantly reduce the life of the generator. In severe cases, it can cause insulation damage, breakdowns and accidents;
Condensation will easily occur if the wind temperature is high. too weak and dropsAll water will condense on the generator. The insulation capacity of the generator coil is reduced, threatening the safe operation of the generator.