Insulated Bearings for Traction Motors Ceramic To prevent electric pitting, NSK developed ceramic coating insulated bearings and PPS-resin coating insulated bearings. Relationship between temperature and insulation resistance of ceramic-insulated bearings was assessed. As a result, no deterioration of insulation resistance up to 110° C was observed. Product Features • Isolating Items • Down-sizing • Long life • High reliability • High strenghten cage Condition Description • Electrical leakage • High Accuracy • Electric pitting protection • Proper cage design (DGBB and CRB) • Proper contact point design (CRB) • Traceability • Roughness control of the raceway • Roller and ball surface • Bearing material are vacuum degassed for high purity • Dimensional stability of bearing steel • Bearings are manufactured to ISO Class 6