The new METAS Watt Balance, Mark II

In the context of the future new definition of the mass unit, kg, a promising route to link the mass unit to a fundamental constant, the Planck constant h, is represented by the watt balance experiment. Since a number of years, the Federal Institute of Metrology is active in this field and published a first result with its Mark I experiment in 2011. To reach the target uncertainty of 2 parts in 10 8 , the Mark II METAS watt balance is being developed. In this paper, the different modules of the experiment are presented and their respective metrological requirements and experimental behaviour are discussed.