Analysis And Calculation Of Ventilation And Heat Dissipation Of Main Helium Ventilator Driving Motor

With the development of modern industry, variable frequency asynchronousmotor have been more and more widely applied in all kinds of industrial field, suchas, mine, electric power, chemical industry, nuke industry and so on. So, theoperation reliability of the variable frequency asynchronous motor became the focusof attention. In this paper, a4500kW main helium ventilator driving motor as theresearch object. The motor is a variable frequency asynchronous motor with heliumcooling. The motor is a driving equipment of the coolant circulation in one loop ofHigh-temperature gas-cooled reactor nuclear power plant. It need to have highreliability and long service life. The judge of operation reliability of variablefrequency asynchronous motor primarily reflected research of temperature field inthe normal operation. If the temperature rise exceeds the value of permitting, it couldcause the breakage of insulation and ageing, motor short circuit seriously, which leadto damage of the motor. Therefore, accurate description about the temperature fielddistribution in main helium ventilator driving motor under different frequency notonly improve the reliability of the motor and prolong the service life of the motor,but also is very important for the safe operation in nuclear power station.The analysis of ventilation structure and type of cooling, the fluid nature andfeatures in the main helium ventilator driving motor is given. The loss of differentparts and coefficient of heat transfer under different frequency in the variablefrequency motor is calculated. Using the finite volume method to establish theventilation model of the main helium ventilator driving motor. The fluid velocity ofeach part in the motor is calculated. Using the fluid similar theory to establish themotor ventilation model. And using fluid-solid coupling method to calculatetemperature field of the variable frequency motor under frequency13Hz，67Hz， 71Hz. A comparative of influence of temperature changes under different frequencyis analyzed. The paper analyzed temperature of stator under insulation material Alevel、B level、C level. Fluid flowing is very complex in the air of motor due torotation of the rotor. When cooling air goes into radial ventilation ducts at differentincidence angle30°、45°、60°、90°, a comparative of temperature changes in thestator is analyzed. The paper analyzed the temperature field of rotor including slotinsulation or without slot insulation under different frequency. The different factorsthat have effect on the temperature field have been discussed，the factors providethe necessary guidance about performance, the service life of motor, the designtheory of motor.