A new electric magnet with four operating modes for magnetic suspension

摘要

Hitherto the researches of an electric magnet for magnetic suspension are mainly the development ofthe material and the improvement of the form or arrangement of the magnet. On the other hand theresearches in respect to the improvement of dynamic characteristics of the magnet are hardly held inrecent years. In this paper the authors propose a new electric magnet with four operating modes, ofwhich modes are switched autoaatically depending on the exciting current. This magnet consists of anelectric magnet with two windings, an analog switch equipped with four diodes, dc power supply andcompensating circuit for the improvement of the frequency response. As the new one has a wide frequency bandwidth, the suspension system constructed by this oneis expected to have the fast respons. This paper describes the steady-state and dynamiccharacteristics of this new magnet. The usefulness of the poroposed electric magnet was verified byexperiments.