Basic experimental and numerical investigations to improve the modeling of the electrical capacitance of rolling bearings

• Published in: Tribology international 2024-05, Vol.193, p.109354, Article 109354
• Main Authors: Gonda, Attila, Paulus, Stefan, Graf, Simon, Koch, Oliver, Götz, Stefan, Sauer, Bernd
• Format: Article
• Language: English
• Subjects: Contact capacitance; EHL; Electrical capacitance of rolling bearings; Electromobility; FEM; Inverter induced bearing currents; Thrust bearing
• ISSN: 0301-679X
• DOI: 10.1016/j.triboint.2024.109354

In modern frequency inverter controlled electric drive trains, parasitic electric currents can occur in rolling bearings and lead to damages of the bearing components. In the prediction of bearing currents, the bearing capacitance plays a major role. It is commonly calculated based on the Hertzian area and the central lubrication gap height of the contact of the rolling contacts using different correction factors. In this work, a combined simulation model is presented to calculate the rolling bearing capacitance. It considers the capacitance of the rolling contact as well as the regions outside the contact domain. The model consists of an electrically extended EHL simulation of the rolling contact and a FEM simulation of the surroundings. The results of the combined simulation method show a good agreement with experimental results without the use of correction factors. •Determination of rolling contact capacitance by EHL simulation.•Cavitation and lubricant properties (density, viscosity, permittivity) considered.•Capacitance calculation of the contact surroundings by FEM simulation.•Combining capacitances of contacts and contact surroundings to bearing capacitance.•Results show good agreement with measured bearing capacitance.•Contact surroundings and varying lubricating oil level affect bearing capacitance.