1 kN·m binary dead weight torque standard machine at SASO / NMCC

Abstract

A 1 kN·m binary dead weight torque standard machine was established at National Measurement and Calibration Center (SASO/NMCC) in 2019 by TÜBİTAK UME. Realisation of torque unit is based on the definition of torque and directly traceable to the mass, length, and time units. It is performed by a lever arm and deadweight system. The lever arm is symmetrical and supported by an air bearing. The machine has two identical and independent dead weight sets, work according to a binary system to create right and left hand torques. All dead weights are under the influence of local gravity and air buoyancy. The machine can apply torque from 1 N·m to 1000 N m with a resolution of 1 N m.

This paper describes the mechanical structure of the machine and uncertainty assessment. The relative expanded measurement uncertainty is smaller than 1 × 10⁻⁴ in the range of 1 N·m to 1000 N m.