| 摘要 |
A vacuum pump 10 comprises a rotor 14 supported for rotation by a drive shaft 16. There is a main magnetic bearing 22 and a back-up mechanical bearing assembly 24 to limit excessive movement of the rotor. A sensor 26 senses when movement is limited by the back-up bearing assembly. The sensor 26 may be an accelerometer which senses a force imparted to the drive shaft 16 sufficient to cause the back-up bearing to limit movement resulting from the force. The force may result from bumps, knocks or impacts, or from moving a mobile pump 10 over an uneven surface. The processor 32 may count the number of events when movement has been limited by the back up bearing. It may also determine the force of an impact, so that it counts a value indicative of cumulative force. |
