Laminated magnetic flux sensor for thick-steel-plate control

This paper presents a rugged magnetic flux sensor, which can measure the thickness of steel plates and can operate reliably in the poor environment of a warehouse for thick steel plates. The sensor, consisting of a laminated sensing plate and a sensing coil, has a size of 6*6 cm/sup 2/, and it is embedded inside the core of a lifting magnet. Depending on the thickness of steel plates attached on the lifting magnet, the magnetic permeability of the core and the sensing plate changes. The thickness of steel plates is indirectly measured by measuring the changes in the magnetic flux density of the sensor. The measurement sensitivity of the magnetic flux sensor with laminated sensing plate is much better than that of a sensor with a solid sensing plate. With a proper procedure for securing measurement reliability, it is demonstrated that the sensor can measure up to 13 sheets of 6mm steel plate.