Failure analysis on abnormal wear of roller bearings in gearbox for wind turbine

The booming wind power industry as one of the predominant approaches of renewable energy resources is not independent of components reliability within the wind turbines, especially the rotating ones including blades, motors, gearboxes etc. Hence, case studies on failed parts of such components play an important role for failure prevention and deserves to be publicly reported for experience sharing. In this paper, a failure case concerning severe abnormal wear of the roller bearing's inner ring in the gearbox of one 1.5 MW wind turbine in China was reported. Since such roller bearings were imported from a foreign company and operated by a Chinese company, not only economic losses but also international commercial dispute would be induced if this case would not be immediately and properly solved. To this end, by means of comprehensive and systematic investigation into the base materials, process media, surface morphologies, micro-area compositions and even service environments, root causes of this failure were determined, detailed mechanisms were discussed, and pertinent countermeasures were proposed. Achievement of this paper would provide the solid evidence to distinguish the responsibilities for the failure, and would also help to prevent such failures of roller bearings with similar design in wind turbines.