Method of avoiding resonance of rotor supported by mangetic bearing

Abstract

Abstract PURPOSE: To avoid resonance, by superposing electrical currents flowing through electromagnetic coils including currents for vertical position control, with such currents that forces caused by two magnetic bearings act vertically symmetrically, to increases the radial ridigity of a shaft. CONSTITUTION: The stator sections 2a, 2b of a first and a second magnetic bearings 1a, 1b are coupled to each other by a non-magnetic member. The rotor sections 4a, 4b of the bearings 1a, 1b are also coupled to each other by a non-magnetic member. The bearings 1a, 1b are arranged vertically symmetrically. Since the positional change of the rotor section 4a of the bearing 1a due to graviation or the like means the opposite positional change of the rotor section 4b of the other bearing 1b, magnetic fluxes ϕ 3 , ϕ 3 ' for controlling the positions of the rotor sections 4a, 4b are set in an identical form as to the vertical direction. Electrical currents are superposed on electromagnetic coils 14a, 14b to generate vertically symmetric magnetic fluxes ϕ c , ϕ c ' in addition to the former magnetic fluxes ϕ 3 , ϕ 3 '. Since the forces caused by the magnetic fluxes ϕ c , ϕ c ' are vertically symmetric, the forces attract or repulse each other so that they are cancel each other. Therefore, they hardly influence the vertical position. COPYRIGHT: (C)1982,JPO&Japio

Inventors

• 👤 Tsutomu Murakami

Bibliographic Details