The electrically insulated bearings to protect against damage caused by electric current.The problem of electric current passing through rolling bearings and causing damage in the contact area of balls or rollers and raceways of inner and outer rings has been known for almost 70 years. In addition to the damage to bearing elements, it was also supposed that the structure of the lubricant itself might change under the influence of a passing current. All rotating machines, both AC and DC motors, potentially suffer from this phenomenon.  Electrically insulated bearings to protect against damage caused by electric current. These bearings are provided with an electrically insulated coated outer ring (VL0241 series). The coating consists of a nominal 100 µm thick aluminum oxide layer and is applied by a special coating process using plasma-spraying technology. The dimensions and tolerances of INSOCOAT bearings are the same as for standard bearings ). For DC currents, the coating acts as a pure resistor and guarantees sufficient insulation against electric currents. The ohmic resistance is far bigger than 50 MW. Leading manufacturers of electrical machinery and traction motors today use INSOCOAT bearings. These bearings are also used for other railway applications, such as wheel bearings and axleboxes.