Optimized coating

Whether in traction motors in rail transport technology, in wind energy or in drive technology: electric motors or generators with frequency converters are increasingly being used. With regard to rolling bearings, this trend always entails the risk of electrical voltage developing between the inner and outer ring. The passage of current can lead to serious damage to both the lubricating grease and the rolling elements and raceways, and rolling bearings failing prematurely. It is therefore sensible to take preventive measures at the planning stage to prevent such damage and failures. Schaeffler now offers improved current-insulating bearings in the J20G series for this purpose.

The new bearings in the J20G series from Schaeffler have an optimized Insutect A coating. This makes it even easier to prevent the risk of current passing through. "Wherever electricity can flow through bearings, there must be good insulation. Otherwise, parasitic currents can cause significant damage and wear to rolling bearings and lubricants, resulting in unplanned downtime and high maintenance costs," explains Manuela Bärthlein from global product management for current-insulating bearings at Schaeffler. "Our customers benefit from our many years of experience in the field of current insulation. With the new bearings, they can significantly increase the reliability of their systems."

High insulation protection thanks to new coating process

The outsides of the outer and inner rings are coated with Insutect A, an insulating aluminum oxide coating that is applied using plasma spraying. In order to achieve even more reliable protection against the passage of current, Schaeffler has once again significantly improved the coating process for the bearings - this means that even more efficient insulation protection can be guaranteed even under demanding operating conditions, such as high humidity. This results in reduced maintenance costs, higher machine availability and operational reliability, and an increased service life of the lubricating greases used.

The bearings can withstand direct voltages of at least 3,000 volts and have a higher impedance and an ohmic resistance of at least 250 megaohms. The aluminum oxide layer is very hard, wear-resistant and a good heat conductor. In order to meet different requirements, the bearings are available as standard in the J20GA, J20GB and J20GI variants. The J20GB layer thickness offers better protection for higher electrical currents, such as those found in the railway sector. The highest level of protection is achieved here by bearings with a coated inner ring (J20GI). Other variants are available on request.

Dimensions according to DIN 616 for maximum flexibility

The external dimensions of the bearings correspond to the dimensions according to DIN 616, so they have the same dimensions and tolerances as standard bearings and are easily interchangeable. Deep groove ball bearings and cylindrical roller bearings are most commonly used with an aluminum oxide coating, but other designs can also be supplied with the coating on request. Bearings with Insutect A coating from Schaeffler meet all requirements in terms of service life, maintenance intervals, operational reliability and cost-effectiveness.

In addition to bearings with coated rings, Schaeffler also offers hybrid bearings with ceramic rolling elements, which offer the highest resistance to the passage of current. For applications with increased requirements or an outside diameter of less than 120 mm, Schaeffler experts recommend the use of hybrid bearings. Thanks to the comprehensive portfolio, Schaeffler customers can find the right solution for every application.