Measurement of Axis Eccentric of Round Rod by Multi Giant Magnetoresistance Probe

Eddy currents induced on the surface depend on properties on near-surface of conductive materials and the arrangement between exciting coil, detecting sensor, and materials, as lift-off height and inclination. We apply the multi-sensor probe for the applications of eddy-current testing to detect the center of small round metal. The measurement system detects the magnetic fields around the round metal simultaneously and estimates the gap and direction of axis eccentric. We describe the principle of detection and the experimental results.