Numerical Calculation Of Electromagnetic Fields And Temperature Fields Of Large And Medium Asynchronous Motor

The practical operation of large and medium asynchronous motor is a very complex physical process. To describe exactly this physical process, it is necessary to analyze it from the angle of coupled fields including electromagnetic fields and temperature fields. Because insulation layers in stator coils for large and medium salient synchronous generator are very thin, they are always out of consideration when calculating electromagnetic field in the previous period. But the whole areas of stator strands insulation may exceed or approach that of one piece of conductor, thus it will have a certain effect on the calculation precision. Simultaneously, in the calculation and analysis of large and medium asynchronous motor, insulation layers often are neglected, but coefficient of thermal conductivity of insulation much smaller, which will affect thermal conductivity of strands, so significant temperature variation of much thin insulation layers will occur ,which will affect the design of motor.In this paper, according to the theory of electromagnetic fields, firstly, electromagnetic field of large and medium asynchronous motor is calculated from the angle of coupled fields, secondly, the end voltage of the stator is taken as constraint condition and starting current in stator is iterated in the numeral computation process, finally starting current and starting torque at rated voltage are gained, and by comparing calculation results with test results ,starting performance of large and medium asynchronous motor meet the demand of project practice. In temperature field calculation, YB560M1 asynchronous motor in Jiamusi Electric Machine CO., Ltd is taken as an example, stator thermal field of large and medium asynchronous motor by FEM is calculated. the solved region of half a tooth, half a slot, half a ventilating groove in stator and half a tooth, half a slot, half an axial length is respectively determined. Simultaneously, by virtue of the Theory of Fluid Similarity, the new method to calculate radiating factor of surface in radial ventilating groove is given, further more, the distribution of temperature in motor is gotten. In this paper, the effect of insulation of stator strand on temperature fields is also studied, at last, by comparing theoretical calculation results with experimental results, calculation proves to be accurate and the study indicates to be of the certain project significance.