Contact dynamic response with misalignment in a flexible rotor/magnetic bearing system

Patrick S. Keogh, Matthew O. T. Cole

Research output: Chapter or section in a book/report/conference proceedingChapter in a published conference proceeding

1 Citation (SciVal)


This paper investigates the vibration characteristics of rotor displacement signals in a magnetic bearing system under conditions when rotor contact with auxiliary bearings is possible. Since these signals may be used for feedback control, it is necessary to determine how they may affect the ability of the controller to regain rotor levitation. An experimental system is used to demonstrate the sensitivity of the rotor non-linear dynamic behavior to unbalance, which is sufficient to cause contact during rotor run up through rigid body and flexural mode critical speeds. Complex rotor dynamics may involve contact with more than one auxiliary bearing or bush. Application of appropriate rotating forces to the rotor through a magnetic bearing is also shown to induce similar contact dynamics. Thus an alternative procedure for assessing the non-linear rotor dynamic behavior is established with the potential for identification of appropriate control forces. The contact dynamics are also considered in the presence of auxiliary bearing misalignment. Misalignment may arise through physical translation of a housing or through steady state offset errors in sensor measurements. A misalignment of 50% of the nominal radial clearance is applied at an auxiliary bearing. Various contact modes are evident as the rotor is run up in speed. During run down different contact dynamics may be encountered and the level of such hysteresis is assessed.
Original languageEnglish
Title of host publicationProceedings of the ASME Turbo Expo, 2004
Subtitle of host publicationPower for Land, Sea and Air
Place of PublicationU. S. A.
ISBN (Print)9780791841716
Publication statusPublished - 2004
EventASME Turbo Expo, 2004 - Vienna, Austria
Duration: 14 Jun 200416 Jun 2013


ConferenceASME Turbo Expo, 2004


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