Applicability of Torque Calibration on Test Benches for Electrical Machines

Abstract

The traceability of torque measurements on test benches for electrical machines is primarily established by the static calibration of a torque transducer. However, the loading conditions and signal processing methods are generally different for the static calibration and the measurement on a test bench. Therefore, the applicability of the calibration should be clarified before applying the calibration results for further analysis. In this paper, the torque measurement chain using a power analyser on a test bench for electrical machines is compared to the measurement chain used in the standard calibration procedure DIN 51309.

Traceable efficiency determination of a 2.75 MW nacelle on a test bench

“…Compared to static torque calibration, torque in NTBs is measured under rotation with ripples and a noisier signal. Moreover, disturbances under rotation will result in insta-bility in control, the effect of which was investigated from a metrological perspective in [18]. As described in Sect.…”

“…Fig 18. Variance of the averaged torque values for each of the six revolutions and the resulting variance in speed and generator power output at 1.5 MN • m and 12.5 rpm…”

Validation of a traceable efficiency determination method for wind turbines with a focus on measurement uncertainty

“…When measuring electrical and mechanical quantities, a stationary state (minimised periodic effects) must be reached before signal averaging per operating point is done. A previous work (Song et al, 2022) thoroughly details the stability of torque measurement points under rotary conditions on an SSTB for electrical machines. That paper highlights the torque measurement deviation caused by significant torque ripples, which serve as an additional source of uncertainty in the SSTB.…”

“…That paper highlights the torque measurement deviation caused by significant torque ripples, which serve as an additional source of uncertainty in the SSTB. In our research work, we have also adopted the stable load step methodology, which involves signal averaging per operating point and utilizes a measurement instrument configuration similar to that outlined in the previous paper (Song et al, 2022) for rotating machines on the SSTB. Here, signal averaging in the SSTB is done over a constant time interval (minimum 8 s, here 10 s) and multiple revolutions and fragments of a revolution.…”