Effect of Inclined Static Eccentricity Fault in Single Stator-Single Rotor Axial Flux Permanent Magnet Machines

This paper studies the effects of static eccentricity on axial flux permanent-magnet machines (AFPMMs) using three-dimensional finite-element analysis (3-D FEA). Use of numerical modeling makes it possible to precisely study the eccentricity in these types of machines. The accuracy of the FEM model is validated using experimental measurement. To the best awareness of the authors, effects of static eccentricity in AFPMMs have not been studied before. Hence, a new definition for the static eccentricity factor (SEF) is presented and it is shown that the occurrence of static eccentricity is very high in these types of machines. A motor with different degrees of rotor eccentricity is simulated and the flux density distribution in the air gap and the total axial force between rotor and stator is obtained. In addition, unbalanced magnetic force (UMF) is calculated and it is mentioned that a steady torque is created by the forces. This study indicates that static eccentricity has noticeable effects on motor characteristics and can deteriorate the motor performances.