Low noise sensitivity magneto-electrical distance transducer - has distance and direction transducer pairs on permanent magnet, typically cobalt samarium alloy

摘要

A magneto-electrical distance transducer has a toothed element moving on a linear or circular path and a magnetic sensor which converts its motion into periodic electrical signals via detection of magnetic field strength variations. The arrangmenet exhibits low sensitivity to noise from mechanical vibrations and external magnetic noise fields. The sensor contains two pairs of magneto-electrical transducers (10,20) mounted on a permanent magnet (30), one (20) for direction and one (10) for displacement measurement. The displacement measurement transducer pair (10) is placed on the axis of symmetry of the equipotential field profile of the permanent magnet. The permanent magnet is a cobalt samarium magnet whose pole surface is large compared to the effective measurement surfaces of the transducer pairs. The transducer pairs may be in the form of pairs of field plates.