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
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