The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 04, 2003
Filed:
Oct. 10, 2000
Ebara Corporation, Tokyo, JP;
Abstract
A magnetic levitation control apparatus comprises a pair of electromagnets for holding a levitated body having a magnetic body in the levitated state. A signal source for supplying a voltage signal of a frequency on a level such that enables the electromagnets to function as the position sensor, wherein a control voltage signal for controlling the magnetic attraction of the electromagnets is superimposed on the voltage signal. A circuit differentially supplies the voltage signal to the pair of electromagnets to form a position signal of the levitated body from an add signal of currents respectively from the electromagnets, and a circuit detects a control current of the electromagnets from a subtraction signal of currents respectively from the electromagnets. A controller generates a control voltage signal of the electromagnets from the detected position signal of the levitated body and, in addition, corrects the position signal detected from the detected control current of the electromagnets.