MAGNETIC-FIELD CALCULATION IN PERMANENT-MAGNET MOTORS WITH ROTOR ECCENTRICITY - WITHOUT SLOTTING EFFECT

An analytical technique for predicting the instantaneous magnetic held distribution in the air gap region of permanent magnet motors with ro tor eccentricity is developed, The governing equations and associated boundary conditions are formulated and solved by a perturbation method . The predicted solutions are verified by the results of a correspondi ng finite element analysis. The results show the effectiveness of usin g the perturbation method for this eccentric field calculation, Accord ing to this study, the additional flux density due to rotor eccentrici ty is proportional to the amount of the eccentricity in a small range and has a quite different distribution from the normal flux density wi thout rotor eccentricity, Accordingly, rotor eccentricity mag cause un desirable effects on brushless permanent magnet motors.