SKF has developed a range of hybrid bearings, specially for wind turbine generator applications, that do not allow the passage of electrical currents. Such currents would lead to electrical erosion of the raceways and eventual bearing and generator failure. They also tend to break down the structure of the lubricant which also heavily affects the bearing performance.

Generator repairs are extremely costly because they are located at the top of wind turbines. The location also makes repairs much more time consuming, and costly, than ground based generator repairs. And once the generator is damaged, additional losses are incurred because the turbine is not producing electricity.

SKF XL hybrid bearings are deep groove ball bearings that have normal steel rings and high grade silicon nitride ceramic balls. Silicon nitride is non-conducting so electricity cannot pass through. And so they prevent electrical erosion at the interface of the balls and the rings, that affects steel-on-steel bearings. The new bearings are available in standard ISO dimensions for the 4 most common bearing sizes for larger generators.

The many benefits of SKF XL hybrid bearings will contribute to lower life cycle cost of the generator and lower total cost of operation of the wind turbine.