Bearing coating for current passage protection

Current passage can significantly damage lubricants, rolling elements and raceways, leading to premature bearing failure. As a result, implementing measures to prevent such damage and failures is advisable at the early planning stage. Schaeffler has now introduced improved current-insulated bearings from the J20G series to mitigate this risk.

On the new J20G series bearings the outer surfaces of the outer and inner rings are coated with Insutect A, an insulating aluminium oxide coating applied using plasma spraying. Schaeffler has refined the bearing coating process for enhanced reliable protection against current passage to provide a more efficient insulation protection, even under challenging operating conditions such as high humidity. The result is reduced maintenance costs, increased machine availability and operational safety, and an extended grease service life.

The bearings can withstand direct voltages of at least 3,000 volts and exhibit a higher impedance and an ohmic resistance of at least 250 megaohms. The aluminium oxide coating is extremely hard, resistant to wear, and a good conductor of heat. The bearings are available as standard in the J20GA, J20GB, and J20GI variants to meet diverse requirements. The J20GB coating thickness provides enhanced protection for higher electrical currents, such as those encountered in the rail sector. The highest level of protection is achieved with bearings that feature a coated inner ring (J20GI). Other variants are available upon request.

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