Analysis of electrical motor mechanical failures due to bearings

Regardless of the high operational reliability of modern ball and roller bearings and advanced methods for their selection and durability calculation, a significant proportion of the failures in the electric motors, about 51% [1], are of mechanical nature. Often, mechanical damage leads to irreversible engine states and costly replacement. Careful theoretical analysis of bearing failures may indicate the root causes of their defects mainly from external for the bearings surface factors and to recommend proper preventive actions. Damage cause can undoubtedly refer to the way in which significant mechanical energy generated in the rotor is transmitted, most often through belt drives or elastic couplings, while the bearings themselves withstand the significant reaction forces that have occurred. A model analysis will be performed to reveal the interconnection of the mechanical power output of an electric motor via belt drive or an elastic coupling to the internal loads and friction of supporting ball or roller bearings. In addition, a suitable lubrication regime for bearings will be examined according to different types of bearings, shaft speed and temperatures. (paper)