Wind Turbine Generator Bearing Fault Diagnosis Using Amplitude and Phase Demodulation Techniques for Small Speed Variations

Vibration analysis of the generator bearing of a large wind turbine using demodulation techniques is discussed in this paper. The purpose of this paper is to show how capable these techniques are for small shaft speed variations. Highest energy band was calculated by wavelet packet transform for amplitude and phase demodulation. Results from the vibration analysis were consistent with a localized outer-race bearing fault. They were then validated by cutting the bearing with water jet machine. A significant localized fault was found on the outer race.