First measurements of the flux integral with the new NIST-4 watt balance

Published

March 31, 2015

Author(s)

Darine El Haddad, Frank Seifert, Leon Chao, Yusi A. Cao, Georgio A. Sineriz, Jon R. Pratt, David B. Newell, Stephan Schlamminger

Abstract

In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance, similar to a mass comparator, the gravitational force of an unknown mass is compensated by an electromagnetic force produced by a coil in a magnet system. The electromagnetic force depends on the current in the coil and the magnetic flux integral. Most watt balances feature an additional calibration mode, referred to as velocity mode, which allows one to measure the magnetic flux integral to high precision. In this article we describe first measurements of the flux integral in the new watt balance. We introduce measurement and data analysis techniques to assess the quality of the measurements and the adverse effects of vibrations on the instrument.

Citation

IEEE Transactions on Instrumentation and Measurement

Volume

64

Issue

6

Pub Type

Journals

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Keywords

Electromagnetic measurements, measurement standards, measurement units, permanent magnets, precision engineering, electronic kilogram, watt balance

Citation

El Haddad, D. , Seifert, F. , Chao, L. , Cao, Y. , Sineriz, G. , Pratt, J. , Newell, D. and Schlamminger, S. (2015), First measurements of the flux integral with the new NIST-4 watt balance, IEEE Transactions on Instrumentation and Measurement, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=916648 (Accessed October 8, 2025)