SCHAEFFLER PRESENTS ITS NEW BEARINGS WITH OPTIMISED COATING FOR IMPROVED PROTECTION AGAINST CURRENT PASSAGE

The use of electric motors and generators with frequency converters is becoming increasingly common in sectors such as rail transport, wind energy and drive technology. However, this trend carries with it the risk of electrical voltage being generated between the bearing rings, which can lead to premature failure due to wear of lubricants, rolling elements and raceways. To mitigate this problem, Schaeffler has developed a new bearing series with improved electrical insulation: the J20G series.

Improved protection with Insutect A coating

The new bearings in the J20G series feature an optimised Insutect A coating based on aluminium oxide applied by plasma spraying. This coating offers more effective protection against eddy currents, thus reducing the risk of bearing damage and minimising maintenance costs.

Manuela Baerthlein, Global Product Management for electrically insulated rolling bearings at Schaeffler, emphasised the importance of this technology: ‘When current can flow through bearings, robust insulation is essential. Without this protection, stray currents can severely damage bearings and lubricants, resulting in unscheduled downtime and high maintenance costs. With our new bearings, customers can significantly improve the reliability of their systems.

Technical features and operational benefits

J20G bearings can withstand currents up to 3,000 volts and have a minimum ohmic resistance of 250 megohms, providing high electrical impedance. The aluminium oxide coating is not only extremely hard and wear-resistant, but also acts as a good thermal conductor, which promotes efficient heat dissipation.

To suit different applications, Schaeffler offers several coating variants:

• J20GA, J20GB and J20GI as standard versions.
• J20GB, with a thicker coating, is ideal for railway applications where higher electrical currents are present.
• J20GI, with a coated inner ring, providing the highest level of insulation.

Interchangeability and complementary solutions

Bearings in the J20G series comply with DIN 616, allowing them to be interchangeable with standard bearings without the need for additional equipment modifications. In addition to bearings with aluminium oxide coating, Schaeffler offers hybrid bearings with ceramic rolling elements, which provide the highest resistance to current flow. For applications with high insulation requirements or outside diameters of less than 120 mm, the company's experts recommend the use of hybrid bearings.

With this new range of electrically insulated bearings, Schaeffler reinforces its commitment to operational reliability and maintenance optimisation in critical industrial applications.