Abstract
Recently, it is necessary for rotors of centrifugal compressors, industrial rolls and so on to be high speed rotation, long span and light weight, because of increase in productivity. However, such rotor is easy to have high order mode at the same rotational speed, and it may become unstable. In order to solve this problem, active magnetic bearings are used to support the flexible rotor. However, since a general active magnetic bearing uses bias current to control bearing force, it consumes large electricity. In this paper, a hybrid active magnetic bearing which consists of electromagnets and permanent magnets is used to reduce the power consumption. The hybrid active magnetic bearing has negative stiffness not only in radial direction but in tilt direction. Experimental results show that the hybrid active magnetic bearings can support the flexible rotor stably.
