EP2106505A1 - Procédé de détermination des fréquences de résonance d'un rotor à palier magnétique - Google Patents

Procédé de détermination des fréquences de résonance d'un rotor à palier magnétique

Info

Publication number
EP2106505A1
EP2106505A1 EP08701225A EP08701225A EP2106505A1 EP 2106505 A1 EP2106505 A1 EP 2106505A1 EP 08701225 A EP08701225 A EP 08701225A EP 08701225 A EP08701225 A EP 08701225A EP 2106505 A1 EP2106505 A1 EP 2106505A1
Authority
EP
European Patent Office
Prior art keywords
rotor
frequencies
frequency
magnetic bearing
determination
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08701225A
Other languages
German (de)
English (en)
Inventor
Ulrich Jung
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Leybold GmbH
Original Assignee
Oerlikon Leybold Vacuum GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Oerlikon Leybold Vacuum GmbH filed Critical Oerlikon Leybold Vacuum GmbH
Publication of EP2106505A1 publication Critical patent/EP2106505A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406—Magnetic bearings
    • F16C32/044—Active magnetic bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
    • F04D19/048—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps comprising magnetic bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/001—Testing thereof; Determination or simulation of flow characteristics; Stall or surge detection, e.g. condition monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C39/00—Relieving load on bearings
    • F16C39/06—Relieving load on bearings using magnetic means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H13/00—Measuring resonant frequency
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M13/00—Testing of machine parts
    • G01M13/04—Bearings
    • G01M13/045—Acoustic or vibration analysis
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/08—Structural association with bearings
    • H02K7/09—Structural association with bearings with magnetic bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2360/00—Engines or pumps
    • F16C2360/44—Centrifugal pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2360/00—Engines or pumps
    • F16C2360/44—Centrifugal pumps
    • F16C2360/45—Turbo-molecular pumps

Definitions

  • the invention relates to a method for determining resonance frequencies of a rotor mounted with an active magnetic bearing.
  • machines with a magnetically mounted rotor are generally fast-rotating machines, for example turbomolecular vacuum pumps.
  • the rotational frequency of the rotor is controlled so that the critical natural frequency of the rotor, so no so-called resonant frequency, if possible during operation not or as short as possible with the rotational frequency to avoid resonance or to minimize and in this way to avoid mechanical overstressing of the rotor.
  • the resonant frequencies for each model are determined experimentally and the speed control of the pumps of the particular model are rigidly adjusted to avoid rotor resonance frequencies and to drive up and down be traversed as quickly as possible. Because of the exemplary scattering within a model and possible changes over the entire operating period, relatively high certainties must be provided around the experimentally determined model resonance frequency.
  • the object of the invention is in contrast to provide a method by which the resonant frequencies of a magnetically levitated rotor can always be accurately determined.
  • the method according to the invention relates exclusively to a magnetically mounted rotor, as is frequently the case in turbomolecular vacuum pumps.
  • mechanical vibrations of the rotor are generated by the electromagnets of the rotor magnetic bearing.
  • the generated rotor vibrations are detected or detected by the rotor position sensors of the magnetic bearing. From the detected vibrations and the information about the frequency of the generated vibrations, the resonant frequencies of the rotor can be determined.
  • the resonant frequencies of the rotor are therefore determined at rotor rotational frequencies, by which no mechanical resonance of the rotor is excited.
  • the described determination of the resonance frequencies can be carried out while the rotor is stationary.
  • the determination of the resonance frequencies is more accurate with a slowly rotating rotor because the resonant frequency of the rotor changes with its dynamic load during rotation.
  • the frequencies of the vibrations generated are at least partially above the rotor rotation frequency.
  • the motor does not need to be rotationally excited to detect its resonant frequencies.
  • the rotational frequency of the rotor during the resonance frequency determination should be as low as possible in order to reduce the risk of collision or to minimize the damage in the event of a collision.
  • a resonant frequency determination at low rotor rotational frequencies or at standstill allows a rapid determination of the resonant frequencies, since a lengthy ramp-up of the rotor rotational frequency is eliminated or only little time occupies.
  • the actual determination of the resonant frequencies of the rotor can possibly be made within a few seconds.
  • the rotor rotational frequency during oscillation generation and the resonant frequency determination is less than 70% of the nominal rotor rotational frequency, more preferably less than 30%.
  • rotor rotational frequencies of 10% of the rotor nominal rotational frequency already allow a determination of the rotor resonance frequencies with sufficiently high accuracy.
  • the rotor nominal rotational frequency can also be selected between two resonance frequencies of the rotor. Due to the exact piece-related resonance frequency determination frequency bands are determined for the operation of the rotor, which could not be used with inaccurate knowledge of the resonant frequency because of the then required collateral under certain circumstances.
  • the present method has the advantage of being able to determine individual resonant frequencies for each individual rotor. Since the determined resonance frequencies are known individually for each individual rotor, the rotor can in principle be operated at rotational frequencies which are closer to the individual rotor resonance frequencies, since there are no corresponding securities for scattering, as would be provided at fixedly programmed resonance frequencies.
  • Turbomolecular vacuum pumps in particular, have shown that considerable specimen scattering of the critical resonance frequencies from specimen to specimen of a model can be detected, so that the knowledge of the actual rotor-related resonance frequencies brings great advantages.
  • the determination of the resonance frequencies with the described method can be carried out at the first commissioning of the relevant machine with the rotor, but can also be done alternatively or additionally regularly or after longer downtime.
  • mechanical vibrations of different vibration frequencies are generated by the magnetic bearing electromagnets.
  • oscillations of the entire rotational frequency frequency spectrum can be generated, in which the relevant machine or the relevant rotor is to be used.
  • the frequency spectrum to be generated by the magnetic bearing solenoids in the rotor can also be limited to the critical ranges known and typical of the particular machine model or rotor model.
  • the method relates to the determination of resonance frequencies of a magnetically levitated rotor of a turbomolecular vacuum pump.
  • the gaps between the pump rotor and the pump stator are extremely small, so that the operation of the rotor with or in the vicinity of its resonance frequency brings with it a considerable risk of collision.
  • considerable collateral must be taken into account because of the specimen scattering.
  • the rotor of a turbomolecular vacuum pump consists inter alia of a shaft on which a motor rotor and a pump rotor are fixed. Furthermore, rotor-side components of the magnetic bearing can be provided on the shaft, for example permanent magnetic sleeves, rings, etc.
  • Stator music are u. a. a pump stator, a motor stator and stator-side parts of the magnetic bearing provided.
  • the stator-side parts of the magnetic bearing include u. a. several electromagnets, which are controlled by a magnetic bearing control.
  • rotor position sensors are provided on the stator side, which can determine the exact rotor position with high measurement frequency and high accuracy.
  • a stationary test run is performed before the first start-up and at regular intervals before the rotor is raised to its operating rotational frequency.
  • the rotor is held by the magnetic bearing electromagnets on the one hand in the floating operating position and on the other hand acted upon by mechanical vibrations.
  • the magnetic bearing generated in this way rotor vibrations over a frequency spectrum by a resonant frequency or more resonance frequencies are expected based on the design or the model of the vacuum pump.
  • the rotor position sensors determine whether or not the rotor oscillates at the respective oscillation frequency generated by the magnetic bearing electromagnets.
  • the resonance frequency of the rotor which can change over the operating time, can be determined at any time with high accuracy.
  • relatively narrow frequency bands around the determined rotor resonance frequency can be placed as a safety.
  • the rotor or turbomolecular vacuum pump can thus be operated at rotational frequencies which, if desired, are relatively close to a resonance frequency determined in this way.
  • the region around the resonant frequency must be traversed as quickly as possible. Also for the startup of the vacuum pump to a supercritical speed of the accurate information about the resonant frequency of the rotor is of great importance.
  • the maximum rotational frequency as close as possible below the rotor resonance frequency.
  • an operating rotational frequency can be selected which may be higher and thus closer to a resonant frequency than would be possible if the specimen spread of the resonant frequency were not known.
  • the maximum rotational frequency of a turbomolecular vacuum pump can be increased by up to 10% - 15%.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Acoustics & Sound (AREA)
  • Non-Positive Displacement Air Blowers (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)

Abstract

L'invention se rapporte à un procédé de détermination des fréquences de résonance d'un rotor à palier magnétique, notamment un rotor d'une pompe à vide turbomoléculaire. Pendant l'arrêt du rotor ou la rotation du rotor à une fréquence de rotation relativement faible, des oscillations mécaniques du rotor sont générées par les électroaimants du palier magnétique. Les oscillations du rotor sont détectées par des capteurs de position du rotor situés sur le palier magnétique. Les fréquences de résonance du rotor sont déterminées à partir des oscillations détectées de la position du rotor.
EP08701225A 2007-01-05 2008-01-03 Procédé de détermination des fréquences de résonance d'un rotor à palier magnétique Withdrawn EP2106505A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007001201A DE102007001201A1 (de) 2007-01-05 2007-01-05 Verfahren zur Ermittlung von Resonanzfrequenzen eines magnetgelagerten Rotors
PCT/EP2008/050043 WO2008081030A1 (fr) 2007-01-05 2008-01-03 Procédé de détermination des fréquences de résonance d'un rotor à palier magnétique

Publications (1)

Publication Number Publication Date
EP2106505A1 true EP2106505A1 (fr) 2009-10-07

Family

ID=39301082

Family Applications (1)

Application Number Title Priority Date Filing Date
EP08701225A Withdrawn EP2106505A1 (fr) 2007-01-05 2008-01-03 Procédé de détermination des fréquences de résonance d'un rotor à palier magnétique

Country Status (9)

Country Link
US (1) US20100072845A1 (fr)
EP (1) EP2106505A1 (fr)
JP (1) JP2010515004A (fr)
KR (1) KR20090098914A (fr)
CN (1) CN101583799A (fr)
CA (1) CA2674263A1 (fr)
DE (1) DE102007001201A1 (fr)
RU (1) RU2009129879A (fr)
WO (1) WO2008081030A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103196672B (zh) * 2013-03-01 2015-07-01 北京中科科仪股份有限公司 一种磁悬浮分子泵径向保护轴承检测方法
CN103994889B (zh) * 2014-05-27 2016-12-07 南京航空航天大学 一种基于电磁激励的滚动轴承故障检测平台及其检测方法
CN106969893B (zh) * 2017-05-26 2024-02-20 成都中科卓尔智能科技集团有限公司 非接触式构件刚度检测设备及方法
US11047387B2 (en) * 2017-09-27 2021-06-29 Johnson Controls Technology Company Rotor for a compressor
CN108429405B (zh) * 2018-01-26 2020-02-18 瑞声科技（南京）有限公司 线性电机共振频率的检测方法及装置

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5258923A (en) * 1987-07-22 1993-11-02 General Electric Company System and method for detecting the occurrence, location and depth of cracks in turbine-generator rotors
JPH01116318A (ja) * 1987-10-28 1989-05-09 Natl Aerospace Lab 能動形磁気軸受
JP3090977B2 (ja) * 1991-05-31 2000-09-25 株式会社日立製作所 磁気軸受けの制御方法及び装置
DE69319004T2 (de) 1992-03-09 1998-12-24 Hitachi, Ltd., Tokio/Tokyo Verfahren und Gerät zur Steuerung eines Magnetlagers
ATE189741T1 (de) * 1994-04-05 2000-02-15 Monitoring Tech Corp Nichtinvasives verfahren und vorrichtung zur feststellung der resonanzbedingungen von bauelementen einer rotierenden maschine mit vorhersage von bauelementfehlern durch änderung dieser bedingungen
JPH08121477A (ja) 1994-10-24 1996-05-14 Seiko Seiki Co Ltd 磁気軸受の制御装置
JP3083242B2 (ja) * 1995-04-27 2000-09-04 核燃料サイクル開発機構 回転体の静止場での振動評価方法
US5663894A (en) * 1995-09-06 1997-09-02 Ford Global Technologies, Inc. System and method for machining process characterization using mechanical signature analysis
US5818137A (en) * 1995-10-26 1998-10-06 Satcon Technology, Inc. Integrated magnetic levitation and rotation system
DE69628036T2 (de) * 1995-12-25 2004-04-08 Takara, Muneaki, Naha Elektromagnetischer kolbenmotor
JP3114085B2 (ja) * 1996-01-31 2000-12-04 セイコー精機株式会社 半径方向位置修正電磁石付磁気軸受装置
DE19619997A1 (de) * 1996-05-17 1997-11-20 Karlsruhe Forschzent Verfahren zum Bestimmen der Unwucht und zum Auswuchten eines supraleitend magnetgelagerten Rotors
JP3109023B2 (ja) * 1996-07-18 2000-11-13 セイコー精機株式会社 磁気軸受装置
DE19828498C2 (de) * 1998-06-26 2001-07-05 Fraunhofer Ges Forschung Verfahren zum Messen von Unwuchten rotierender Körper und Vorrichtung zur Durchführung des Verfahrens
DE20021970U1 (de) * 2000-12-30 2001-04-05 Igus Ingenieurgemeinschaft Umweltschutz Meß-und Verfahrenstechnik GmbH, 01099 Dresden Einrichtung zur Überwachung des Zustandes von Rotorblättern an Windkraftanlagen
JP2004286045A (ja) 2003-03-19 2004-10-14 Boc Edwards Kk 磁気軸受装置及び該磁気軸受装置を搭載したポンプ装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2008081030A1 *

Also Published As

Publication number Publication date
WO2008081030A1 (fr) 2008-07-10
CA2674263A1 (fr) 2008-07-10
US20100072845A1 (en) 2010-03-25
RU2009129879A (ru) 2011-02-10
JP2010515004A (ja) 2010-05-06
KR20090098914A (ko) 2009-09-17
CN101583799A (zh) 2009-11-18
DE102007001201A1 (de) 2008-07-10

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