Overview of Bearing White Etching Cracks due to Electrical Currents

With the development of variable speed drives, motor bearings are submitted to additional stress due to parasitic currents which deteriorate bearing raceways, rolling elements and lubricant. Electrical bearing damage, identified by microcraters resulting in surface degradation of raceways and rolling elements, can occur rapidly under adverse operating conditions. Meanwhile bearing currents have been found to be one of the influent drivers of an unconventional rolling contact fatigue (RCF) mode known as white etching cracks (WEC). It is characterized by a wide subsurface cracks network which leads to premature bearing failure. This paper presents the actual knowledge that link bearing currents to white etching cracks initiation and formation.