A BRG arrangement has been developed including shaft position (displacement), temperature, speed and acceleration measurement on the generator. Load units have been designed to apply and control external loads. Overall, a highly capable and highly integrated test rig arrangement has been designed, manufactured, built and commissioned. The simulation chain has been developed and applied. A bearingless test option with x-y force measurement has been developed, simultaneously measuring bearing load and displacement, enabling the full validation of the electro-mechanical simulation chain. In addition, to the investigations at the Topic Leaders site, bearing tests were performed at WZL of RWTH Aachen to validate the bearing friction under radial load. A new concept was developed to measure the friction of the generator bearings under radial load and a corresponding test rig setup was designed, manufactured and finally tested on spindle bearings.
All of this provided the Topic Leader, the University of Nottingham with a highly capable test rig that allows it the freedom to investigate and demonstrate the capabilities of the exciting technology of the Bearing Relief Generator and to develop it further.
The test rig was commissioned successfully and it was confirmed by testing that the test rig met the requirements set by the Topic Leader for testing the radial force control technology. The replacement inverter used for the tests had a significantly lower power capability (compared to the designed inverter), so only relatively small forces could be applied. However, it was demonstrated that the forces applied by the inverter and the corresponding change in displacement can be measured and thus the test setup is working stable with a sufficiently high resolution, capturing these rather low forces and displacements. Once the designed inverter is available testing across the full operation envelope will be conducted, and the test results will be used to fully validate the developed simulation tool chain and to quantify the benefits of the BRG technology.
Three journal papers and one conference presentations have been published in relation to the project, as well as several work shop contributions. A further two conference presentation abstracts were accepted and three journal papers are currently in the submission and review process. A full set of test results will be obtained and will enable both the quantification of the BRG performance and benefits and the validation of the developed simulation tool chain. These data are crucial for both the Topic leader and the consortium for exploitation. The exploitation is by no means restricted to the aerospace industry, the automotive (for electric vehicles) and power generation (high-speed applications) industries also look promising. Furthermore, the application in the manufacturing industry, by both WZL of RWTH Aachen and Romax/Hexagon Manufacturing Intelligence, specifically machine spindle applications will be exploited. The active control of the spindle stiffness and therefore the cutting force generation can be utilized to improve surface quality, reduce tool wear and extend spindle life.
