AGMA 13FTM15 PDF

Bearing failures in wind turbine gearboxes were investigated and rolling contact fatigue tests to reproduce them using a hydrogen-charge method were conducted. Two main failure modes in wind turbine gearbox bearings were white structure flaking and axial cracking, which were involving a microstructural change. Both failure modes can be reproduced by using specimens charged with hydrogen. Operating conditions, which can induce hydrogen generation from lubricant and penetration of the bearing steel were discussed. Effects of bearing material on white structure flaking life were suggested as one of the countermeasures.