| 摘要 |
PROBLEM TO BE SOLVED: To provide a turbo-molecular pump device which surely senses a degree of damage of a protecting bearing. SOLUTION: Before or after operating the turbo-molecular pump 1, time to be required for deceleration from a constant numberω1 of revolution to a constant numberω2 of revolution smaller than the rated number of revolution of a rotary shaft 3 of the turbo-molecular pump 1 is measured, and the measured deceleration time and a set time previously obtained by a test are compared with each other, and when the measured deceleration time is longer, the friction torque is small, and the protecting bearings 11 and 12 are determined normal, and when the measured deceleration time is shorter, the friction torque is large, and the protecting bearings 11 and 12 are determined unusual. COPYRIGHT: (C)2004,JPO
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