Stabilizing a floating disc — Analysis, field and lateral force calculation

The electromagnetic field and force calculations on a metallic disc, placed above two series opposing concentric coils, is difficult since the integrodifferential equations are involved and do not yield a closed form solution. Several analytical, semi-analytical and numerical techniques based on FEM are already developed to find the magnetic fields and forces on the disc which is coaxial with the coils. A new approach to solving the integrodifferential equations by mathematical formulation using Finite Difference method (FDM) has been proposed to calculate the magnetic fields due to induced eddy currents and the electromagnetic force on the disc by discretization of the disc into several curvilinear meshes. The axial position of floating disc and maximum lateral displacement of the disc when it moves away from the axis of coils due to any disturbance has been analyzed in this paper. A MATLAB program has been developed to calculate these fields and force on the disc. The axial floating position of the disc is determined by the electromagnetic force (lift force) developed on the disc and the maximum lateral displacement of the disc from the radial component of force.