Magnetised surface sensor arrangement - has side-pieces of windings vertically stacked for equalised response to same defects whether close to or far from surface

摘要

A sensor arrangement is for scanning the surface of a magnetised ferromagnetic workpiece. The sensors are arranged to have similar sensitivity to magnetic dispersion deriving from faults. At least one induction sensor consists of a set of windings. Each winding has one side-piece placed near the surface to be scanned and running in parallel to it, while the side-piece on the opposite side remains at a distance from the surface. The former side-pieces (25), i.e. those nearer the surface under test (23), of the separate windings (41) are at least partially separated from each other vertically w.r.t. the surface (23). The spacing is so measured that the induction sensor.