Bearing Current Remediation Options: Sources, Investigative Measurements, and Installation Modifications to Reduce Damage as a Result of Bearing Currents

BEARING CURRENTS IN INDUCTION motors can result in premature bearing failure. In across-the-line driven electric motors, current-related bearing failures can occur due to a flow of current that is internally generated in the motor. The increased use of variable speed drives in industrial and commercial electric motor systems has raised the awareness of users as to a new source of bearing current flow that is externally sourced due to the switching characteristics of the inverter power source. Current paths within the motor and throughout the inverter-driven motor system must be well understood in order to apply effective bearing current remediation methods for these types of applications.