Practical Rules for Assessment of Inverter-Induced Bearing Currents in Inverter-Fed AC Motors up to 500 kW

The influence of different parameters of a variable-speed drive system on the phenomena of inverter-induced bearing currents has been studied under exactly the same conditions on inverter-operated alternating current motors from 1 to 500 kW. Detailed modeling may not always be applicable with practical applications in the field, where many parameters might be unknown. Therefore, the most important correlations are summarized in the form of a flowchart that is based on the physical cause-and-effect chains. This flowchart can serve as a tool for engineers to estimate the endangerment of a drive system due to inverter-induced bearing currents and select an appropriate mitigation technique if necessary, where detailed knowledge of the different design parameters is not available