Patent ID: 9417156
Filing Date: 2016-08-16
CPC Classification: G01M

Claim Text:
1. A method for assessing damage to a rolling bearing of an electric machine connected to an inverter caused by bearing currents, wherein the rolling bearing has lubrication gaps disposed between an inner bearing ring and a rolling body and between an outer bearing ring and the rolling body, the method comprising the steps of: searching for discharge events by performing measurements in two different frequency ranges, wherein a first frequency range is located in a single-digit to multi-digit megahertz range, and a second frequency range is located at a frequency above one GHz, determining an energy of an electric discharge event in at least one of the lubrication gaps from a measurement in the first frequency range, searching in the second frequency range for a discharge event coincident with the electric discharge event, measuring a frequency of occurrence of coincident discharge events, and correlating the coincident discharge events with damaging bearing current events.