Optimization Procedure for the Determination of Faraday’s Voltage in UME Kibble Balance (July 2018)

The ultimate goal of redefining the SI unit of mass in terms of a fixed value of the Planck constant may be achieved by means of Kibble balance principle, previously known as watt balance principle. We present an optimization procedure for the determination of Faraday's voltage in the recently constructed second-generation UME oscillating-magnet Kibble balance apparatus where the misalignment between the electric center of the coil and the magnetic center of the magnet is treated as a parameter contributing to Faraday's voltage rather than as a contribution to the uncertainty budget. Such an optimization procedure not only makes it possible to reach target uncertainties without having perfect alignment but also allows the determination of statical parameters of force and torque by only measuring dynamical parameters of the displacement and voltage. Restricted by the repeatability of the Faraday's voltage measurements, further improvements of this optimization procedure may be possible via the integration of programmable Josephson voltage standard into the system and the determination of eddy current effect.