  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.
