Abstract The Joule balance method is one of the methods to redefine and realize the kilogram based on the Plank constant. Considering the unideal initial position and gesture of the suspended coil, it hard to achieve an ideal balance between the electromagnetic force and weight gravity, and then alignment errors are produced. It is one of the largest uncertainty sources in the Joule balance. Based on the mechanism of the alignment errors and combined with mechanical and electromagnetic properties of the Joule balance, the model between the initial position and gesture of the suspended coil and its parasitic displacements is build up and analyzed. The theory will lay the foundation of restraining the alignment errors.
BAI Yang,WANG Da-wei,LI Zheng-kun, et al. Recognition of Initial Position and Posture of Suspended Coil in Joule Balance[J]. Acta Metrologica Sinica, 2020, 41(3): 273-278.
［1］Newell D B, Cabiati F, Fischer J, et al. The Codata 2017 Values of H , E , K , and N a for the Revision of the Si［J］. Metrologia, 2018, 55(1): L13-L16.
［2］Antonio P, Stephan S, Sara S, et al. Evaluation of the Accuracy, Consistency, and Stability of Measurements of the Planck Constant Used in the Redefinition of the International System of Units［J］. Metrologia, 2018, 55(1): 29.
［3］宋明顺, 方兴华, 马爱文. 论新国际单位制(SI)的“秒制”特征及其未来发展 ［J］. 计量学报, 2019, 40(4): 541-548.
Song M S, Fang X H, Ma A W. The Characteristics of the New SI Base on “second system” and its Future Development ［J］. [WTBX][STBX]Acta Metrologica Sinica[STBZ][WTBZ], 2019, 40(4): 541-548.
［4］Ivashchuk V D, Kononogov S A, Mel’nikov V N. Results of Measuring the Avogadro and Planck Constants for a Redefinition of the Kilogram and Mole［J］. Measurement Techniques, 2014, 57(2): 125-131.
［5］Robinson I A. Watt and Joule Balances［J］. Metrologia, 2014, 51(2): S1-S3.
［6］Bettin H, Schlamminger S. Realization, Maintenance and Dissemination of the Kilogram in the Revised Si［J］. Metrologia, 2016, 53(5): A1-A5.
［7］Zhang Z H, He Q, Li Z K. An Approach for Improving the Watt Balance［C］//Proceedings of the 2006 Conference on Precision Electric Measurements Torino: IEEE, 2006: 126-127.
［8］Zhang Z H, He Q, Li Z K, et al. Recent Development on the Joule Balance at Nim［J］. IEEE Transactions on Instrumentation and Measurement, 2011, 60(7): 2533-2538.
［9］Li Z K, Zhang Z H, Lu Y F, et al. The First Determination of the Planck Constant with the Joule Balance NIM-2［J］. Metrologia, 2017, 54(5): 763-774.
［10］Zeng T, Lu Y F, Liu Y M, et al. A Capacitive Sensor for the Measurement of Departure from the Vertical Movement［J］. IEEE Transactions on Instrumentation and Measurement, 2015, 65(2): 458-466.
［11］Liu Y M, Zeng T, Cao J R, et al. Evaluation of Vertical Movement Precision of the Exciting Coil Along the Gravity Direction in Joule Balance NIM-2［J］. Measurement, 2016, 92(1): 144-149.
［12］Zeng T, Lu Y M, Yang H X, et al. System for the Measurement of the Deviation of a Laser Beam from the Vertical Direction［J］. Applied Optics, 2016, 55(10): 2692-2700.
［13］Robinson I A. Alignment of the NPL Mark II Watt Balance［J］. Measurement Science and Technology, 2012, 23(12): 1-17.
［14］Sanchez C A, Wood B M. Alignment of the Nrc Watt Balance: Considerations, Uncertainties and Techniques［J］. Metrologia, 2014, 51(2): S42.
［15］曾涛, 鲁云峰, 李正坤, 等. 能量天平水平安培力与电磁转矩引起对准能量误差的评估［J］. 计量学报, 2018, 39(6): 753-758.
Zeng T, Lu Y F , Li Z K, et al. Joule Balance Alignment Energy Error Evaluation by Horizontal Ampere Force and Electromagnetic Torque［J］. Acta Metrologica Sinica, 2018, 39(6): 753-758.
