What can bearings bear?

This paper studies the series of 22 test runs performance for bearing damage assessment due to inverter-induced bearing currents. The influence of bearing current amplitude and type, calculated apparent bearing current density, time of operation, and inverter switching frequency on bearing damage was investigated. The degree of electrical bearing stress W was introduced. The degree of melting of the bearing race surface and the grade of reduction of the carboxylic acid bound in the grease, which is an indicator for the deterioration of the grease, depend on W