The development of wind turbines into multi-megawatt power plants leads to increasingly higher forces and torque which in turn subject the components to ever-increasing loads. At the same time, any downtimes and maintenance work generate higher costs, especially in the case of offshore installations. A phenomenon that has a negative influence on the reliability of bearings, not only in the wind power sector, are the so-called white etching cracks (WEC) and as such, reliable components have a key role to play.
WEC are structural changes in the material that form below the surface of the bearing. These changes result in the formation of cracks which extend to the surface during stress conditions under different external loads. As a result, the inner or outer ring may crack and cause the affected bearing to prematurely fail. These cracks occur in both through-hardened and case-hardened rolling bearings. Schaeffler’s innovative solutions help increase the resistance of the bearings to WEC and prevent premature bearing failure.
It is still not completely clear what causes WEC to occur. In line with current knowledge however, there is scientific proof according to which, additional stresses in the form of dynamics, mixed friction and the effects of electrical systems create the conditions needed for WEC to form. Read more…
Article published in: FuturENERGY June 2015