| 摘要 |
PROBLEM TO BE SOLVED: To improve reliability of a magnetic bearing device by devising it to provide the maximum braking effect and to reduce impact force to a touch- down bearing on the magnetic bearing device constituted to brake by giving command rotational frequency to a motor at the time when a rotary shaft to integrally rotate with a rotor of the motor and to be held floating by an electromagnet makes contact with the touch-down bearing. SOLUTION: This device changes command rotational frequency in accordance with loweringΔ(n) of rotational frequency of a rotary shaft. That is, rotational frequency of the rotary shaft is detected every specified time (SA1), new command rotational frequency fr(n) lowered by a value larger by an amountαthan a different between rotational frequency f(n) and previously detected rotational frequency f(n-1) is against the newly detected rotational frequency f(n) (SA3), and this command rotational frequency fr(n) is given to a motor.
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