RWTH Aachen University
Torque Measurement in Wind Turbines Test Benches
Temperature is considered to be a decisive environmental parameter for torque measurement on wind turbine test benches. The Chair for Wind Power Drives of RWTH Aachen University is therefore investigating their influence on such test rigs.
Components such as prime movers, hydraulic power units, load application systems and electrical converters are responsible for the heat input in such test benches. They contribute to the temperature fluctuations of the test bench shaft and the torque transducer and can thus reduce the accuracy of the torque measurement.
Complete Power Train Measured
To quantify the influence of temperature on torque measurement accuracy in the MN∙m range (meganewton meter range), it is important to measure the area temperature of the entire torque transducer. The InfraTec VarioCAM® HD research 700 infrared camera is very well suited for this purpose. It allows simultaneous temperature measurement of the entire drive train using a 15 mm wide-angle lens.
RWTH Aachen University uses a 4 MW wind turbine test bench for analysis. The temperature measurements are carried out under different operating conditions and as long-term measurements of up to 10 hours to investigate the cooling and heating process of the drive train. The VarioCAM® HD research 700 is positioned at different locations to separately measure the temperature distribution of a tested 5 MN∙m torque transducer and following that of the existing stationary torque transducer of the test bench.
The measurement results can be used to optimise simulation models by adjusting the material properties of the transducer and the strain gauge factors. The result is a more precise quantification of accuracy in torque measurement.