Stray capacitances in the watt balance operation: electrostatic forces
  In a watt balance, stray capacitances exist between the coil and the magnet. Since the electric current flowing in the coil originates a difference between the coil and magnet electric-potentials, their electrostatic interactions must be taken into account. This paper reports the results of a finite element analysis of the forces acting on the coil. 
Danilo Quagliotti and Giovanni Mana
physics.class-ph