Calculation And Research On Heat, Refrigeration And Temperature Field In Water-cooled Explosion-proof Motor

The explosion-proof motor, used in the machine for excavating thin coal bed, has a technical developing trend of more power and more power density. Along with the continuous increase of the design capacity of motor unit volume losses in the motor increase, which lead to the rise of temperature in every part of the motor. So improving cooling system and confining temperature difference become one primary problem in the development of technology in the machine for excavating coal. The motor used in the machine for excavating coal is usually installed in a limited space and operated in bad ventilation circumstance, so realizing temperature distributing in every part of the motor can avail to optimum cooler design.In this paper, according to an actual motor used in the machine for excavating coal in Jixi coal mine, the mathematical model for the temperature field of a rating motor was established, while geometry and material form of the model is building on the sample motor YBCM150-4. By the methods of finite element, relational electromagnetic quantities can be obtained. The result is credible and electromagnetic losses of the motor can be worked out by magnetic density we got. In fact, the electromagnetic losses are just the heat sources in the temperature field. By using the fluid soft, fluid velocity field in the air gap of the motor can be simulated and the air gap of the motor can be divided into two parts. One is laminar flow lay whose heat exchanging is mostly thermal conductivity, the other is mussy flow lay whose heat exchanging is mostly force convection. Compared with laminar flow lay, thermal resistance in the mussy flow lay can be ignored. By the methods of equality of thermal resistance, the average conductivity in the air gap of motor can be switched. Upon that the boundary condition of temperature field can be confirmed and 2D temperature field can be calculated and analyzed in the stator, rotor and water jacket of the motor. It can be found that the highest temperature of stator is in the lower layer of the coil near the air gap, where we can set an electric coupling and monitor its variety of temperature to protect safe operation of motor. Moreover, the temperature in the stator coil can be reduced effectively if the rate of water in the jacket increase, and we should select proper rate to obtain the best cooling effect.