International Comparison of Torque Standards between the National Metrology Institute of Japan (NMIJ) and Korea Research Institute of Standards and Science (KRISS)

摘要

An international comparison of torque standards was conducted between the National Metrology Institute of Japan(NMIJ) in the National Institute of Advanced Industrial Science and Technology (AIST) and the Korea Research Institute of Standards and Science (KRISS). Three high-performance torque transducers and one bridge calibrator were used as transfer devices. A pair of identical amplifier/indicator, one each at each laboratory, was used for the comparison. The two transducers, the rated capacities of which were 2 kN(centre dot)m and 1 kN(centre dot)m, were transferred from the NMIJ to the KRISS, and the other transducer, having a rated capacity of 500 N(centre dot)m was sent from the KRISS to the NMIJ. Deadweight torque standard machines rated at 1 kN(centre dot)m and 20 kN(centre dot)m at the NMIJ and a deadweight torque standard machine rated at 2 kN(centre dot)m at the KRISS were compared. The relative deviations of calibration results were less than 4.3 X 10~(-5) for increasing torque, and were less than 5.8 X 10~(-5) for decreasing torque. Sufficiently small deviations were obtained as contrasted with their best measurement capabilities (both 5.0 X 10~(-5) as relative expanded uncertainties), so that the equivalence of the torque standards between the NMIJ and the KRISS were confirmed.