Bearing Wear Detection and Rotor Eccentricity Calculation in Radial Flux Air-Gap Winding Permanent Magnet Machines

Electrical generators and other drive-train components experience significant varying loads in wind turbines. This can lead to bearing failure due to unbalanced forces caused by misalignment and rotor eccentricity. This paper presents an analytical model to determine the radial force induced in 50KW air-gap winding permanent magnet generators in wind turbines due to static rotor eccentricity. The model has been verified with 2D electromagnetic finite element analysis software. Depending on fault frequency, Stator currents have been analysed in order to detect bearing wear type (inner race defect, outer race defect or bearing defect).