First Measurements of the Flux Integral With the NIST-4 Watt Balance

Author

Haddad, Darine ; Seifert, Frank ; Chao, Leon ; Cao, Austin ; Sineriz, George ; Pratt, Jon ; Newell, David ; Schlamminger, Stephan

Author_Institution

Nat. Inst. of Stand. & Technol., Gaithersburg, MD, USA

Volume

64

Issue

6

fYear

2015

fDate

Jun-15

Firstpage

1642

Lastpage

1649

Abstract

In early 2014, construction of a new watt balance, named NIST-4, had started at the National Institute of Standards and Technology (NIST). In a watt balance, 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 paper, 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.

Keywords

balances; calibration; coils; magnetic field measurement; magnetic flux; magnetic forces; NIST-4 watt balance; National Institute of Standards and Technology; adverse effect; calibration mode; coil; electromagnetic force; gravitational force; magnet system; magnetic flux integral measurement; measurement quality assessment; Coils; Frequency measurement; Velocity measurement; Vibration measurement; Vibrations; Voltage measurement; Wheels; Electromagnetic measurements; International System of Units (SI); Planck´s constant; Planck???s constant; fundamental constants; precision engineering; watt balance; watt balance.;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/TIM.2015.2407531

Filename

7073581