SL-08-024 -- Different Types of Bearing Currents — The Fundamentals PDF

Papers have been written on bearing currents from various perspectives. This paper addresses the fact that there are a number of mechanisms that can cause bearing currents — even within the application subset of inverter-fed motors — and each of the mechanisms can require its own specific corrective action to mitigate the damage. The actual mechanisms for bearing damage due to current flow have often been misunderstood. This paper attempts to clarify the physics of these damage mechanisms. While this paper addresses currents in the bearings of motors, it should be understood that other machinery — typically machinery coupled to the motor — may be susceptible to similar bearing currents.