| 摘要 |
PURPOSE:To prevent a bearing from being damaged, by performing an idling speed operation in a low speed to an extent such that no solid contact is generated in spiral group dynamic pressure bearing parts, in a fluid transport stop period. CONSTITUTION:A pump control unit 53 enables a frequency H1, for actuating a pump in a rated operation condition, and a frequency H2, for performing a transport stop operation, to be selected. In a fluid transport stop period, a control frequency is selectively changed so as to perform an idling speed operation in a low speed to an extent such that no solid contact is generated in spiral group dynamic pressure bearing parts 14, 18, 22, 27. Accordingly, at the time of stopping, the pump, preventing a bearing from solid contact, enables prevention of damage.
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