An eddy current speed sensor with a novel configuration of longitudinal and transversal coils

Abstract

This paper presents a novel eddy current speed sensor for linear speed measurement of moving flat iron parts. The main goal of the paper is to present an efficient eddy current speed sensor with high sensitivity and faulttolerant capability using novel pickup coil configurations. It has one rectangular excitation coil and two sets of pickup coils for voltage measurement. The first set of pickup coils consists of eleven serially connected coils, which are perpendicularly mounted and arranged on top of the excitation coil in a transversal direction. The second set of pickup coils comprises two antiserially connected pickup coils that are in the same longitudinal direction as the excitation coil. The measurements of the sensor are performed up to +/- 17.9 m/s (64 km/h) at excitation frequencies of 1000 Hz and 4000 Hz. Analytical calculations are used for the parametric and performance analyses of the eddy current speed sensor. The calculation results are compared with the measurements. The sensor's nonlinearity error is 1%. The performance of the sensor is also assessed for a higher speed range, up to 600 km/h.