Impedance Analysis of a Multi-Layer Rhombic Coil Facing to a Moving Sheet Conductor

Abstract

Recently, the usefulness of using parallelogram coil or rhombic coil has been reported in eddy current sensor and eddy current testing. However, the theoretical analysis on these coils has not been made yet. In this paper the exact analysis on magnetic field is carried out with regard to a multi-layer rhombic coil facing to a moving sheet conductor. In addition, the calculation fomula of variation of the coil impedance has been deduced and its validity has been confirmed by the experiment.