| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic bearing device which can reduce the time during which a rotating shaft is decelerated in the event of power failure. SOLUTION: This magnetic bearing device includes a brushless dc motor 1 which drives and rotates a rotating shaft; magnetic bearing means 13, 14 for levitating the rotating shaft magnetically; a magnetic bearing control circuit 6 for controlling the magnetic bearing means; and a forced brake circuit 3 which involves a resistance that is connected in series with the brushless dc motor during power failure. If power is normally supplied from a power supply, the motor controls magnetic levitation using the magnetic bearing means 13, 14 driven under control of the magnetic bearing circuit 6 In the event of power failure, the resistance 31 of the forced brake circuit 3 is connected in series to the motor 11 to convert current flowing through the motor into heat by means of the resistance to perform heated breaking, by means of which the deceleration time of the rotating shaft is reduced.
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