An Oscillating Magnet Watt Balance

TL;DR

This paper introduces a new oscillating magnet watt balance that simplifies the measurement of the Planck constant by using a stationary coil and an oscillating magnet, reducing experimental complexity and improving robustness.

Contribution

The paper presents a novel watt balance design with an oscillating magnet that independently measures force and generates voltage, streamlining the measurement process.

Findings

Principle formulation of the oscillating magnet watt balance.

Reduced sensitivity to environmental disturbances.

Simplified measurement procedure for the Planck constant.

Abstract

We establish the principles for a new generation of simplified and accurate watt balances in which an oscillating magnet generates Faraday's voltage in a stationary coil. A force measuring system and a mechanism providing vertical movements of the magnet are completely independent in an oscillating magnet watt balance. This remarkable feature allows to establish the link between the Planck constant and a macroscopic mass by a one single experiment. Weak dependence on variations of environmental and experimental conditions, weak sensitivity to ground vibrations and temperature changes, simple force measuring procedure, small sizes and other useful features offered by the novel approach considerably reduce the complexity of the experimental setup. We formulate the oscillating magnet watt balance principle and establish the measurement procedure for the Planck constant. We discuss the nature of oscillating magnet watt balance uncertainties and give a brief description of the National Metrology Institute (UME) watt balance apparatus.