| 摘要 |
PURPOSE:To continue operation of a magnetic bearing device until the rotational frequency of a rotor is lowered enough in a device for continuing operation of a magnetic bearing device by utilizing the regenerative power of a motor at the time of service interruption. CONSTITUTION:When feeding to a motor driver 71 is stopped due to service interruption or the like, regenerative power is generated by coils 61U, 61V, 61W with rotation of a rotor of a DC brushless motor. When the rotational frequency of a rotor is high, a switch circuit 88 is off-state so that regenerative voltage is rectified and smoothed by diodes 86a-86f and condensers 83, 84 according to the ordinary rectifying system and supplied to a magnetic bearing control circuit 77. When the rotational frequency of the rotor is lowered, a voltage doubler rectifier command signal 93 is output from a regenerative voltage lowering detecting circuit 90 and the switch circuit 88 is turned on and change-over to the voltage doubler rectifier system takes place.
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