A noncontact conductivity detection method based on the principle of electromagnetic induction

In the paper, a noncontact conductivity detection method based on the eddy current sensors is designed and analyzed. The sensors consist of an excitation coil and a sensing coil. A finite element (FM) model of the two coaxial coils is established for numerical simulation. Numerical analysis and finite element simulations are employed to analyze the relationship between the conductivity of the measured object and the amplitude and phase of the voltage on the sensing coil. Then the excitation frequency and the spacing between the two coils are optimized. The phase of the voltage on the sensing coil is found to be proportional to the conductivity of the measured object. Experiments are carried out and the results show that the proposed method is feasible for conductivity detection.