Computation of additional losses due to rotor eccentricity in electrical machines

This study investigates the effect of eccentric rotor on the power losses in electrical machines. The investigations are carried out for an induction machine with PWM-voltage supply and in the cases of dynamic and static eccentricity. The time-stepping two-dimensional finite element method, with coupled field and circuit equations, is used for the simulations. The iron losses are computed through a dynamic loss model. It is shown that the operation of the machine under eccentricity fault results in an increase of both resistive and iron losses. Further the eccentricity causes additional torque modulation and unbalance magnetic pull that result in additional bearing friction losses and wearing.