Physical modeling of an eddy current sensor designed for real time distance and thickness measurement in galvanization industry

An analytical model of an eddy current sensor designed for noncontact thickness and distance measurement is presented. A dipolar model allows the external physical parameters (conductivity and permeability of alloys) to be taken into account. Analysis of an iron sheet coated with a conductive material gives an accurate interpretation of the detected signals, useful for optimization of the sensor design. Experimental and theoretical data are compared for a galvanization line, demonstrating the potential of this system for nondestructive continuous evaluation