Yusuke Kosugi, Design Section, Large Rotating Machinery Department 1, Rotating Machinery Systems Division, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATION
Solid rotor SMs are used as driving motors for large compressors and mining mills. Since solid rotor SMs are started by eddy current of their magnetic pole surfaces, therefore large losses occur on the magnetic pole surfaces. Due to this loss, the magnetic poles overheat and thermal expansion occurs. That is main cause of rotor unbalance, vibration and cracks of magnetic pole bolts. Hence magnetic pole surface loss and temperature are important design parameters for solid rotor SMs. However it is difficult to design with theoretical equation, because the losses are depended on pole shape. In this paper, magnetic pole surface loss and temperature are estimated using 3D finite element methods (FEM). Furthermore, some measured magnetic pole surface losses and temperatures are compared with 3D FEM results.