Non-destructive testing of a train wheel using a linearly integrated Hall sensor array

An improvement has to be made in the inspection speed and the crack detection ability needed to inspect cracks in express train wheels. In this paper a linearly integrated Hall sensor array (LIHaS) is proposed in order to improve the ability for crack detection. In addition, the exclusive parallel signal conditioning circuits, the analog-to-digital convertors, and the interface were developed to reduce the measurement time. The permanent magnet, which applies the vertical magnetic field to the wheel, and the differential-type LIHaS, which measures the distribution of the magnetic field around a crack, is designed to be buried in the rail. An experiment was performed in order to verify the proposed method.