Current insulated roller bearings
When roller bearings are used in modern, converter-fed three-phase drives,
serious damage is occurring more and more frequently through spark or electro-corrosion. This is usually caused by high-frequency currents flowing through the rolling elements and contact areas within the raceways. These lead to voltage gradients and extreme current peaks, and can cause serious raceway damage depending on duration and energy density. In the worst case, the bearing can fail completely, since the electric discharge causes the material to heat up until the surface melts and the material structure changes.
This damage can easily be avoided, however, by using electrically insulated roller bearings. Reliable and safe insulation is achieved either in the form of a ceramic layer on the outer race or by using ceramic rolling elements. Current insulating bearings can even be retrofitted since they have the same outer dimensions as standard bearings.