A NEW DESIGN OF PRIMARY TORQUE STANDARD MACHINES

H. Gassmann, T. Allgeier, U. Kolwinski

Abstract

GTM have developed a primary torque standard which covers the range from 1 Nm to 1 kNm with a single load frame and only one weight stack per direction of operation. The design comprises a double-sided lever, supported on straincontrolled elastic hinges, a binary weight stack of exchange disk design for each direction, mounting accessories for the transducer under test and a counter-torque drive with servo-controller. Compared to conventional types with air bearings and a multitude of several stacks, the chosen design offers distinctive advantages:<BR />Higher reliability of the lever support, less complicated auxiliary systems, easier method of operation, low overall height. Calculations show that the parasitic moment of the crossed hour-glass shaped springs for the lever support can be controlled to less than 10^-5 N&middot;m for a 1 kN&middot;m machine, and that the uncertainty of lever length falls within a 20 ppm band, including the equality of both sides. Using the same principle of elastic hinges, the overall torque range can be increased to stretch from 0.1 N&middot;m to over 20 kN&middot;m, with only two separate load frames.

Keywords

torque measurement, primary standard, deadweight

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IMEKO-WC-2000-TC3-P070.pdf

DOI

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IMEKO TC

TC3 - Measurement of Force, Mass, Torque, and Gravity

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