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Gearless and compact motors rotating at speeds above 10,000 rpm are finding many applications nowadays. This study presents the multiphysics modelling and analysis of a multilayer printed circuit board (PCB) stator for high-speed, lowpower axial flux permanent magnet motor. The possibility of circulating current in the multilayer PCB is studied. The two major effects of eddy currents at high frequencies: skin effect and proximity effect are investigated for the PCB winding. The losses in the PCB stator are estimated, and thermal analysis is performed to ensure reliable operation of the motor. MagNet 3-D and COMSOL Multiphysics are used, respectively for the finite element analysis and optimisation of the motor; and the simulation results are presented. A prototype of the motor is fabricated and tested to validate the simulation results.

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A bstract-In this paper, the experimental investigation of high speed squinel cage induction motor(750 Hz, 2 pole) has been plesented. Measulement of the equivalent cilcuit panunetem has been discussed in detail. For no-load, stand still test was used instead of light running test. Numerical technique was used for the computation of bridge leakage mactance of the closed rotor slot for various values o f mtor bar cunent Ihe computed values wete compamd with the measumd one. For evaluation of performance of the motor, equivalent cincuit approach was adopted taking into account the non-linearity of various parameters. Shess disbibution in the mtor lamination was also computed using Finite Element Method for various mtor slot-bridge heights. L INTRODUCTIONDue to significant advances in Power Electronics, the high speed direct electrical drive are becoming more promising as compared to other {forms of high speed drives. Research and development activities are being attempted vigorousiy in developing high speed electrical machine of ratings ranging from 10 W to 100 kW level. The speed range considered in the lower power range .( < 1 k W ) is upto 150,000 rpm and in the higher power ranges ( > 1 kW) the speed range is upto 100,000 rpm. For the above mentioned speed and power ranges only induction, hysteresis, permanent magnet and variable reluctance type rotors are possible candidates. In mid 1980's Hesmondhalgh etal [ 1 ] published papers on induction and permanent magnet motors for extremely high speeds ( i.e. 150,000 rpm ). These machines are intended for 10 W to 50 W output power. Chalmers etal [ 2 ] worked on 400 Hz type induction motors in which squirrel cage bars of various :conductivities used for limiting the starting current. Speed range of the motor was of the order of 12,000 rpm. Japanese researchers [ 3 ] [ 4 ] published a few papers on high speed induction and reluctance motors. Chiba etal [ 5 ] demonstrated the operation of high speed induction with built in magnetic bearings. Jayawant etal have anent tempted Vyas etal [ 6 ] have published their work n 75 kVA, In all the papers mentioned above, it has not been rwn the possibility of designing the 30 kW ty e pe aagnet machine suitable for 30,000 rpm. They have i. t put this machine on magnetic bearings.Ip 4,000 rpm type permanent magnet generators.discussed on testing and evaluation of the performance of the high speed machine. In this paper design methodology, experimental results of 75 W, 45,000 rpm type induction motor have been presented. This motor was designed with a rotor having circular closed slots. The mechanical and electrical details are presented in Appendix. Stress distribution of the high speed rotor has also been evaluated using FEM and these results have also been presented for completeness.