Method and apparatus for determining the distance between an electromagnetic sensor and a conductive rail

US4866380A · kind A · utility

Assignee

• Thyssen Industrie AG · DE

Inventors

• Juergen Meins · Braunschweig, DE
• Helmut Grosser · Maisach, DE
• Gerhard Holzinger · Munich, DE

Key dates

• Filing date: Aug 26, 1988
• Grant date: Sep 12, 1989
• Expiry date: Aug 26, 2008

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60L2200/26
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and an apparatus are provided for determining the distance of a probe, particularly a magnetic bearing or a magnetic levitation device, from a conductive reaction rail. The probe comprises at least one sensor having at least two magnetically-coupled coils disposed opposite the reaction rail. The coils generate an alternating magnetic field whose influences (eddy currents) are detected by the sensor and employed for identification of the distance. In order to achieve a high, useful voltage level, insensitivity to external electrical fields and potential fluctuations, as well as a small influence of system-conditioned magnetic fields, the influences of eddy currents induced in the reaction rail by the alternating magnetic field are acquired and utilized for the identification of the distance.