Vibration Criteria Considered from Case Studies of ActiveMagnetic Bearing Equipped Rotating Machines

[摘要] The main part of turbo machinery is conventionally supported by oil film lubricated bearings.The rotor vibrations can be suppressed within low levels as to satisfy vibration criteria, e.g.,ISO standards for general rotors and API 617 for process compressors. Recently, thesophisticated advantages of the active magnetic bearing (AMB) have been increasing thenumber of applications to industrial rotors. The AMB vibration control design requiresthe weak support which induces inevitably large vibration amplitude, though it is normal forAMB itself. Vibration criteria indicated by present standards are thus too strict for AMBequipped rotors. The difference of the bearing dynamic characteristics between the oil filmlubricated bearing and the AMB compels us to prepare a new ISO standard whichrecommends the acceptance of higher vibration levels for AMB operation.In this paper, a case study was executed concerning AMB equipped LP and HPcompressors experiencing long-term operation with no major trouble since December, 1992.The rotating rated speed, 10900 rpm, is beyond the first bending critical speed with 5300 kWof power. The average value of the rotor vibration was about 50 μmpp in the site operation. By reviewing the rotor design concept and field data of these AMB equipped machines, new vibration criteria are considered for a proposal of ISO standardization.

[学科分类] 力学，机械学