Temperature rise subjected to the copper losses and iron losses is an important issue for a magnetically suspended turbomolecular pump (MSTMP). In this study, the loss estimation, thermal analysis, and temperature rise measurement of a large-scale MSTMP are investigated. The copper losses and the iron core losses of two radial magnetic bearings, a thrust magnetic bearing, and a brushless direct current motor (BLDCM) are predicted by the analytical models. Based on the predicted loss values, the

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... heat generation rates in the different parts of the large-scale MSTMP are calculated, then the thermal field of the prototype is analysed by the 3D finite-element model. The maximum temperatures estimated for the rotor part and stator part are located at the rotor sleeve and the winding end of BLDCM, which are 68.5 and 55.2 °C, respectively. The loss calculation and thermal field prediction is validated by the temperature rise test in a prototype of large-scale MSTMP with pumping speed of 4100 L/s, ultimate vacuum of 1.8 × 10 −7 Pa, and rated speed of 21,000 r/min. The maximum error between the estimated and the measured temperature rise values is <5%.