Parasitic loads in torque standard machines:A characterisation, comparison, and evaluation

In torque standard machines, different kinds of bearings are used to reduce the influence of parasitic loads under the assumption that such loads are low. In accordance with EURAMET cg-14, the signal of a torque transducer is averaged over three mounting positions. For this reason, the influence of parasitic loads on the transducer signal should be negligible. To test this assumption, two multi-component torque transducers are characterised in this study based on experimental, analytical, and numerical results. In this article, the parasitic loads of the torque standard machines at the Physikalisch-Technische Bundesanstalt (PTB), Teknologian tutkimuskeskus VTT Oy (VTT), and Cesky Metrologicky Institut (CMI) were characterised and compared. The results are presented together with a proposal for an evaluation.