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:
Jul. 12, 2011
Filed:
Sep. 28, 2010
Toshimitsu Barada, Tokyo, JP;
Toshiya Yoshida, Saitama, JP;
Toshimitsu Barada, Tokyo, JP;
Toshiya Yoshida, Saitama, JP;
Ebara Corporation, Tokyo, JP;
Abstract
An energy-saving magnetic bearing device with no bias current for making the relation between the excitation current and the magnetic force of the electromagnet linear is provided. In a magnetic bearing device for supporting a rotorserving as the magnetic piece in a levitating state allowing free rotation at a specified position by the magnetic force of a pair of electromagnets, the electromagnetsare constituted to interpose the rotorand face each other. A driveris a PWM (pulse width modulation) type driver for controlling the excitation current in the electromagnetsby modulating the pulse width of a voltage driven at a specified carrier frequency fc, and includes a resonator means for electrically resonating at a frequency equal to the carrier frequency fc. When an excitation current flows in either one of the pair of opposing electromagnets, then the other magnet is regulated so that the DC component in the electromagnet excitation current is zero, and a voltage is applied via the resonator means to the electromagnet whose DC component in the excitation current is discharged to zero.