Contactless measuring device for gaps between rolls - has magnetic-field-sensitive semiconductor device to indicate gap width

摘要

A measuring circuit for contactless measurement includes an electromagnet in the magnetic circuit. There is a measuring gap (s) and a semiconductor device sensitive to magnetic fields. The semiconductor device is connected to a circuit which feeds a voltage dependent on the magnetic field (UR) to the terminals of the semiconductor device independently of a constant voltage regulator (A, B) which holds the magnetic induction (B) constant. The current flowing through the semiconductor device (if) is proportional to the magnitude of the measuring gap. The semiconductor device may be a Hall effect device or a magneto-resistive field plate. Suitable semiconductor materials are indium antimonide and indium arsenide.