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AC current automatic calibration using two different TCC designs

 

Rasha S M Ali
 

Department of Electrical Quantities Metrology, National Institute for Standards (NIS), Giza 136

 

Abstract: AC currents are automatically calibrated by two different thermal cur rent converter (TCC) designs. The two designs are different in the used number o f the thermal-elements (TEs). Consequently they differ in their output electro motive force (EMF). Studying the effect of changing the output EMF is done in th is paper through calibrating AC currents. 5 mA and 5 A are accurately calibrated at different frequencies 55 Hz, 1 kHz and 10 kHz by the two TCCs. A comparison is made between the results to evaluate the effect of the output EMF value on th e accuracy and the uncertainty of the low and higher AC current calibration. A L abVIEW program is designed for this accurate automatic calibration to overcome t he problems of the manual calibration on the thermal converters.

 

Key words: AC current calibrations; thermal current converter (TCC); current sh unt resistor; electromotive force (EMF); AC-DC difference; uncertainty

CLD number: TM930.12 Document code: A

Article ID: 1674-8042(2013)03-0205-05 doi: 10.3969/j.issn.1674-8042.2013.03.0 01


References

[1] Williams E S. The practical uses of AC-DC transfer instruments. National Bur eau of Standards, USA, 1982: 1-33.
[2] Lipe T E. A reevaluation of the NIST low-frequency standards for AC-DC diffe rence in the voltage range 0.6-100 V. IEEE Transactions on Instrumentation and Measurement, 1996, 74(6): 913-917.
[3] Fluke Corporation. Calibration: philosophy in practice, 2nd Ed. Everett, USA , 1994: 5-10.
[4] Kinard J R, Williams E S, Lipe T E. Automated thermal voltage converter inte rcomparisons. IEEE Transactions on Instrumentation and Measurement, 1986, 74(1): 105-107.
[5] Mohammed R S A. Design and implementation of precise thermal converters for the highly accurate ac voltage applications. PhD Thesis. Faculty of Engineering, Ain Shams University, 2009.
[6] Hector L, Garcia R, Cioffi J, et al. AC-DC transfer with improved precision. IEEE Transactions on Instrumentation and Measurement, 1995, 44(2): 407-410.
[7] Filipski P S, Boecker M. AC-DC current shunts and system for extended curren t and frequency ranges. IEEE Transactions on Instrumentation and Measurement, 20 06, 55(4): 1222-1227.
[8] Uncertainty guide to the expression of uncertainty in measurement. [2012-12- 03]. http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf.
[9] Saudi Arabian Standards Organization. Guidelines for evaluation and expressi on of uncertainty of measurement in calibration, 2001.
[10] Rasha S M Ali. Comparison between two different designs in the AC voltage m easurement. Measurement Journal, 2011, 44(9): 1539-1542.
 

 

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