Verfahren und Vorrichtung zum Erkennung und Schutz gegen statisches elektromagnetisches Feld an Magnetoelastischem Kraftmesser.

摘要

Method and device for detection of and protection against the effect of disturbing static and/or quasi-static magnetic fields on measurement with a magnetoelastic force and torque transducer which transducer is magnetized by a symmetrical, periodic supply current, the Fourier representation of which only comprises a fundamental wave and odd harmonics of this fundamental wave. If the magnetic flux density B generated in a body of ferromagnetic material by a sinusoidal symmetrical magnetic field strength (magnetization) exhibits even harmonics, this means that the body also has superimposed static and/or quasi-static magnetization. According to the invention the content of even harmonics determined and measured, respectively. The content corresponds to the degree of static and/or quasi-static magnetization and is used as input signal to a regulator (11) which, with the aid of a direct current in, for example, a separate winding (14) reduces the static and/or quasi-static magnetization to zero.