RECALIBRATION OF THE MOMENT ARM LENGTH OF A 10 N·m DEAD WEIGHT TORQUE STANDARD MACHINE AND COMPARISON WITH A 1 kN·m DEAD WEIGHT TORQUE STANDARD MACHINE |
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| Atsuhiro Nishino, Koji Ogushi, Kazunaga Ueda |
- Abstract:
- A 10 N·m dead weight torque standard machine (10- N·m-DWTSM) has been developed and evaluated since 2006. The main parts of the moment arm in the 10-N·m-DWTSM are made of low thermal-expansion alloy (Super Invar). It is known that parts made of Super Invar vary in length with age. In this study, the moment arm length was recalibrated using a 3D coordinate measurement machine. As a result, the moment arm length was found to have lengthened by an average of 6.3 µm in five years. Also, the relative expanded uncertainty of torque, Wtsm, realized by the 10-N·m-DWTSM was revaluated in a range from 0.1 N·m to 10 N·m, and Wtsm was 7.0 × 10-5, with the coverage factor k being equal to 2. In addition, the 10-N·m-DWTSM was compared with the 1-kN·m-DWTSM at NMIJ/AIST by using torque measuring devices after estimating Wtsm realized by the 10-N·m-DWTSM. Equivalence between the two DWTSMs was confirmed within the uncertainty of comparison.
- Keywords:
- torque, uncertainty, Super Invar, secular length change, small torque, intra-comparison
- Download:
- IMEKO-WC-2012-TC3-O31.pdf
- DOI:
- -
- Event details
- Event name:
- XX IMEKO World Congress
- Title:
Metrology for Green Growth
- Place:
- Busan, REPUBLIC of KOREA
- Time:
- 09 September 2012 - 12 September 2012