Detection of planet bearing faults in wind turbine gearboxes

Most gearbox failures in wind turbines initiate in bearings and later advance to gears and other components. Bearings supporting the planet gears exhibit a high failure rate and are considered as one of the most critical components. In order to detect localized defects in planet bearings using vibration measurements, a detailed knowledge of their vibration signature is required. In this paper, we determine the vibration signatures of a planet bearing inner-and outer-race defects using a dynamic model of a wind turbine planetary drivetrain. We also conduct an experimental analysis on a planetary test rig, with seeded planet bearing defects, to validate the theoretical predictions. Defect vibration signatures, determined in this paper, will help to improve the diagnostic techniques for planet bearing faults in wind turbine gearboxes.