SKF’s hybrid bearings with silicon nitride rolling elements and steel rings provide insulation against stray currents in large variable speed electric motors to eliminate electric arc bearing damage and resulting premature bearing failure. According to SKF’s press release, the ceramic rolling elements further make these bearings more durable alternatives to conventional all-steel counterparts. In addition to their insulating properties, silicon nitride balls are 40% less dense than steel balls, which reduces centrifugal force and friction; harder than steel for enhanced wear resistance against hard particles, contaminants, and vibration; and highly inelastic for increased bearing stiffness and reduced deflection under load to promote reliable performance. Standard types include hybrid single row deep groove ball bearings with bore diameters from 5mm to 110mm; sealed and greased-for-intended life ball bearings protected by steel-reinforced synthetic rubber seals and filled with premium lubricant; and open basic design bearings available without seals. Cages are glass fiber-reinforced polyamide or pressed steel, depending on bore size.