Flow diagram Bearing Test Center Copyright: © CWD


Premature damage to rolling bearings reduces the economic efficiency of wind turbines (WT) due to long downtimes and high repair costs. However, currently no methods exist for the qualification of rolling bearings that simulate the real load conditions at the bearings from a WT gearbox. Therefore, research and industry are focusing on the development of test methods to evaluate the reliability of rolling bearings in wind turbine applications. To this end, the Wind Energy Bearing Center was founded in Nordrhein-Westfalen (NRW), where industry and research work acquire knowledge on the development and qualification of rolling bearings considering the entire value chain (bearing, gear and wind turbine manufacturers).

Unique bearing test rigs worldwide

In order to test full-size rolling bearings under real operating conditions, two unique prototype test rigs were set up as part of the WT-BearingCenter.NRW project, which model different stages of a WT gearbox. Thus, rolling bearings of a High-Speed-Shaft (HSS) stage on the one hand and bearings of a planetary stage on the other hand are tested under novel test methods. For the qualification of the HSS and planetary stage (PL) bearings, the Bearing Robustness Test (BRT) was developed, which considers the mechanical loads from 6 years of operation in an accelerated test time. With regard to industrial application, a maximum testing time 1,000 h was defined. Establishing the BRT as a qualification method for rolling bearings reduces the risk of bearing failure in the field and thus increases operational reliability as well as the amount of electricity produced.

Project overview

The procedure of the project WT-BearingCenter.NRW is divided into four phases. The first phase Hardware Implementation has already been completed and included the setup and commissioning of the two prototype test rigs. In the second phase Test Procedures, the BRT test methodology for the HSS and PL bearing test rig was developed. Based on this, an application-specific WEC test for reproducing WEC and qualifying WEC-resistant rolling bearings is currently being developed. The developed test procedures are being applied and validated on the test rigs in the third phase, Validation. Moreover, in the Optimization phase, simulation models are being developed to calculate the influence of the test parameters on the internal load distributions of the bearings in order to optimize the test rigs and test parameters.

With the participation of WT manufacturers and suppliers of rolling bearings and gearboxes, the test rigs and test procedures developed will not only contribute to a more reliable energy supply, but also consolidate and expand NRW's pioneering role in the field of wind turbine drive technology. The project volume amounts to approximately € 7.5 million and is funded by the NRW state government as part of the Leitmarktwettbewerb Energie‑Umweltwirtschaft.NRW. The project started in November 2016 and the consortium consists of funded and associated companies from the wind energy sector. The project is led by the Chair for Wind Power Drives (CWD) at RTWH Aachen University.


Chair for Wind Power Drives
Campus-Boulevard 61
52074 Aachen


10.11.2016 - 09.09.2021

Funded project partners:

Schaeffler Technologies AG & Co. KG

Associated project partners:

Eickhoff Antriebstechnik GmbH Nordex Energy GmbH SE NTN Kugellagerfabrik GmbH SKF GmbH ThyssenKrupp Rothe Erde GmbH Timken Company Vestas Nacelles Deutschland GmbH Winergy GmbH ZF Friedrichshafen AG

Project funded by:

European Regional Development Fund EFRE.NRW 2014-2020

Project promoted by:

Leitmarktagentur Nordrhein-Westfalen