| 摘要 |
PURPOSE:To increase/decrease the load capacity of a radial magnetic bearing device in accordance with the external load of a machine tool spindle etc. to suppress the heat generation in the spindle by providing to the device a controller means for controlling a bias magnetic flux in response to the change of the bearing load thereto. CONSTITUTION:The external load condition of a spindle 1 appears as a displace ment so that it can be detected by a position sensor 5X. The external load condition of the spindle 1 is also expressed by the control current iC which increases according as the external load increases. In order to increase/decrease the load capacity of a magnetic bearing 2 in response to its external load, and output is supplied by a phase compensator 11 to an integrator 13, whose output voltage VC controls the bias current iB. In this manner, the bias current iB is decreased during the load to the spindle 1 is low so that the load capacity of the magnetic bearing is decreased, and only when the external load is in creased, the bias current iB is correspondingly increased with that of the load capacity. |
