MNm Torque: Torque measurement in the MN-m range

Funding: EMPIR (European Metrology Programme for Innovation and Research)
Partners: Federal Physical-Technical Institute (PTB), Spanish Center of Metrology, Tres Cantos (CEM), Czech Metrology Institute (CMI), VTT Technical Research Center of Finland (VTT), CENER-CIEMAT Foundation (CENER), RWTH Aachen University (RWTH)
Duration: 09/2015 – 08/2018


Measurement of the mechanical torque is particularly important for wind turbines as it makes it possible to determine the efficiency of the turbine. The test benches currently in use only allow measurements with the requisite precision to a limited extent. The MNm Torque project aims to remedy this: Within the scope of the project, the largest torque sensor ever to be calibrated at the Federal Physical-Technical Institute (PTB) has been installed on the nacelle test bench at the RWTH in Aachen. Using this new transfer standard, a calibration procedure is being tested which allows traceability for torque measurements of test sequences at the RWTH Aachen to the national standard.

Following initial successful use of the new transfer standard, detailed investigations of how the rotation and the additional wind loads influence the torque measurement will be conducted with the aim of obtaining a precise insight into the technology and the calculation of possible measuring imprecision. A “Best Practice Guide” is also being prepared, which will describe the performance of test bench calibrations and the use of transfer standards in the MN-m range. The developed transfer standard shall remain available for measurements even after the end of the project term.

Fraunhofer IWES is involved in this project in a consulting capacity and will aid the project partners in achieving the objectives by means of the active exchange of experiences and by assessing the methods with regard to their transferability to other test benches.