A New Differential Excitation Eddy Current Sensor Used for Micro-defects on Metal Surface

The paper analyses traditional differential eddy current sensors pointing out that differential excitation eddy current is more suitable for micro-defects detection. Based on this theory, a new kind of eddy current sensor with orthogonal rotating excitation field is proposed. The simulation analysis indicates that this new sensor can generate rotating eddy excitation field. The structure of this new sensor and the signal processing circuit is given in this paper. The correctness and effectiveness of the sensor has been proved through experimental results.