Bearing Wear Due to Mechanical Stresses and Electrical Currents

Passage of current through moving conductive contacts results in electrical discharge and then melting of the material, which leads to wear. Such kind of bearing wear is common in electrical machines. There are however certain patterns which are unique to this kind wear. This wear pattern is called ‘fluting’, which are repetitive in nature. Electrical discharge can create higher surface roughness. Also the thermal and rheological properties of the lubricant play a big role in the film thickness formation. The passage of current through the lubricant also changes this and is determined by the electrical properties of the lubricant. In this work effect of bearing currents on a 7204 angular contact ball bearing is studied. This is tested with and without different cage materials with an axial load and no radial load, rotating at 2700 rpm. Four experiments were done at different-level of voltage, lube and cage material. Type of lubricant was seen to play a significant role in fluting.