DE69810130T2 - Rotationspumpe mit tauchrotor - Google Patents

Rotationspumpe mit tauchrotor

Info

Publication number
DE69810130T2
DE69810130T2 DE69810130T DE69810130T DE69810130T2 DE 69810130 T2 DE69810130 T2 DE 69810130T2 DE 69810130 T DE69810130 T DE 69810130T DE 69810130 T DE69810130 T DE 69810130T DE 69810130 T2 DE69810130 T2 DE 69810130T2
Authority
DE
Germany
Prior art keywords
rotational pump
submersible
rotor
submersible rotor
rotational
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.)
Expired - Lifetime
Application number
DE69810130T
Other languages
English (en)
Other versions
DE69810130D1 (en
Inventor
Maurice Brunet
Eric Helene
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.)
Societe de Mecanique Magnetique SA
Original Assignee
Societe de Mecanique Magnetique SA
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 Societe de Mecanique Magnetique SA filed Critical Societe de Mecanique Magnetique SA
Application granted granted Critical
Publication of DE69810130D1 publication Critical patent/DE69810130D1/de
Publication of DE69810130T2 publication Critical patent/DE69810130T2/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/04Shafts or bearings, or assemblies thereof
    • F04D29/046Bearings
    • F04D29/048Bearings magnetic; electromagnetic
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D13/00Pumping installations or systems
    • F04D13/02Units comprising pumps and their driving means
    • F04D13/06Units comprising pumps and their driving means the pump being electrically driven
    • F04D13/0606Canned motor pumps
    • F04D13/0633Details of the bearings
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D13/00Pumping installations or systems
    • F04D13/02Units comprising pumps and their driving means
    • F04D13/06Units comprising pumps and their driving means the pump being electrically driven
    • F04D13/0606Canned motor pumps
    • F04D13/064Details of the magnetic circuit
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/04Shafts or bearings, or assemblies thereof
    • F04D29/046Bearings
    • F04D29/0465Ceramic bearing designs
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00Bearings not otherwise provided for
    • F16C32/04Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406Magnetic bearings
    • F16C32/044Active magnetic bearings
    • F16C32/0444Details of devices to control the actuation of the electromagnets
    • F16C32/0446Determination of the actual position of the moving member, e.g. details of sensors
    • F16C32/0448Determination of the actual position of the moving member, e.g. details of sensors by using the electromagnet itself as sensor, e.g. sensorless magnetic bearings
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00Bearings not otherwise provided for
    • F16C32/04Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406Magnetic bearings
    • F16C32/044Active magnetic bearings
    • F16C32/047Details of housings; Mounting of active magnetic bearings
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00Bearings not otherwise provided for
    • F16C32/04Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406Magnetic bearings
    • F16C32/044Active magnetic bearings
    • F16C32/0474Active magnetic bearings for rotary movement
    • F16C32/0489Active magnetic bearings for rotary movement with active support of five degrees of freedom, e.g. two radial magnetic bearings combined with an axial bearing
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K11/00Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/30Structural association with control circuits or drive circuits
    • H02K11/33Drive circuits, e.g. power electronics
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K5/00Casings; Enclosures; Supports
    • H02K5/04Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/12Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas
    • H02K5/128Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas using air-gap sleeves or air-gap discs
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05BINDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00Components
    • F05B2240/50Bearings
    • F05B2240/51Bearings magnetic
    • F05B2240/511Bearings magnetic with permanent magnets
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05BINDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00Components
    • F05B2240/60Shafts
    • F05B2240/61Shafts hollow
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2300/00Application independent of particular apparatuses
    • F16C2300/40Application independent of particular apparatuses related to environment, i.e. operating conditions
    • F16C2300/42Application independent of particular apparatuses related to environment, i.e. operating conditions corrosive, i.e. with aggressive media or harsh conditions
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2360/00Engines or pumps
    • F16C2360/44Centrifugal pumps
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K5/00Casings; Enclosures; Supports
    • H02K5/04Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/12Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas
    • H02K5/136Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas explosion-proof
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K7/00Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/08Structural association with bearings
    • H02K7/09Structural association with bearings with magnetic bearings

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)
  • Motor Or Generator Frames (AREA)
DE69810130T 1997-09-12 1998-09-10 Rotationspumpe mit tauchrotor Expired - Lifetime DE69810130T2 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9711363A FR2768470B1 (fr) 1997-09-12 1997-09-12 Pompe rotative a rotor immerge
PCT/FR1998/001935 WO1999014503A1 (fr) 1997-09-12 1998-09-10 Pompe rotative a rotor immerge

Publications (2)

Publication Number Publication Date
DE69810130D1 DE69810130D1 (en) 2003-01-23
DE69810130T2 true DE69810130T2 (de) 2003-09-25

Family

ID=9511018

Family Applications (1)

Application Number Title Priority Date Filing Date
DE69810130T Expired - Lifetime DE69810130T2 (de) 1997-09-12 1998-09-10 Rotationspumpe mit tauchrotor

Country Status (6)

Country Link
US (1) US6350109B1 (de)
EP (1) EP1015770B1 (de)
JP (1) JP3419759B2 (de)
DE (1) DE69810130T2 (de)
FR (1) FR2768470B1 (de)
WO (1) WO1999014503A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006029399A1 (de) * 2006-06-27 2007-03-01 Cincinnati Extrusion Gmbh Elektromotor mit Axiallager
EP4024675A1 (de) 2020-12-28 2022-07-06 Tomas Pink Single-use rotor mit kurzschlusskäfig

Families Citing this family (52)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3421243B2 (ja) * 1998-05-13 2003-06-30 株式会社荏原製作所 キャンドモータポンプ
DE19939522A1 (de) * 1999-08-20 2001-02-22 Wilo Gmbh Elektromotorisch angetriebene Kreiselpumpe mit außenliegendem Rotor
DE10025190A1 (de) * 2000-05-20 2001-12-06 Wilo Gmbh Spaltrohrmotor mit Folienspaltrohr
GB2366332B (en) * 2000-08-30 2004-10-20 Rodney Bruce Gilmour Sealess pump with diametric current drive
NL1018212C2 (nl) * 2001-06-05 2002-12-10 Siemens Demag Delaval Turbomac Compressoreenheid omvattende een centrifugaalcompressor en een elektromotor.
FR2826077B1 (fr) * 2001-06-15 2003-09-19 Mecanique Magnetique Sa Palier magnetique actif a detecteurs integres
US6847140B2 (en) 2002-02-28 2005-01-25 Standex International Corp. Fluid barrier for motor rotor
US6884043B2 (en) 2002-02-28 2005-04-26 Standex International Corp. Fluid circulation path for motor pump
US6814549B2 (en) 2002-02-28 2004-11-09 Standex International Corp. Liner for fluid pump motor
US6863504B2 (en) 2002-02-28 2005-03-08 Standex International Corp. Fluid pump relief valve
US6837688B2 (en) 2002-02-28 2005-01-04 Standex International Corp. Overheat protection for fluid pump
WO2003083311A2 (en) * 2002-02-28 2003-10-09 Standex International Corp. Motor pump
US6626578B1 (en) 2002-03-12 2003-09-30 Buffalo Pumps, Inc. Rotary pump with bearing wear indicator
DE10216402A1 (de) * 2002-04-12 2003-10-23 Wilo Gmbh Kreiselpumpe mit integriertem Magnetfilter
NL1021656C2 (nl) * 2002-10-15 2004-04-16 Siemens Demag Delaval Turbomac Compressoreenheid met gemeenschappelijke behuizing voor elektromotor en compressor, werkwijze voor het vervaardigen van een scheidingswand voor een compressoreenheid en gebruik van een compressoreenheid.
GB2472757B (en) * 2005-01-20 2012-02-01 Martin Lister No sparks dynamo/motor
DE502005004805D1 (de) * 2005-05-07 2008-09-04 Grundfos Management As Pumpenaggregat
US20070086906A1 (en) 2005-10-14 2007-04-19 Wayne Horley Surface pump assembly
FR2897911B1 (fr) * 2006-02-27 2009-03-27 Mecanique Magnetique Sa Soc D Palier magnetique actif chemise
US20070262668A1 (en) * 2006-05-11 2007-11-15 General Electric Company Magnetic Bearings, Armatures for Magnetic Bearings, and Methods for Assembling the Same
AT505598B1 (de) * 2006-12-19 2015-05-15 Manfred Dipl Ing Dr Schrödl Magnetlagereinrichtung
US20080218008A1 (en) * 2007-03-08 2008-09-11 General Electric Company Rotor and Stator Assemblies that Utilize Magnetic Bearings for Use in Corrosive Environments
US7847454B2 (en) * 2007-03-08 2010-12-07 General Electric Company Encapsulated stator assembly and process for making
DE102007011733B4 (de) * 2007-03-10 2009-01-02 Ab Skf Verfahren zum Betrieb eines Kompressors und Kompressor
JP4904251B2 (ja) * 2007-11-29 2012-03-28 株式会社山田製作所 ポンプ用dcモータ
DE102008018407B4 (de) * 2008-04-10 2012-03-22 Joh. Heinr. Bornemann Gmbh Unterwasserförderaggregat
US8696331B2 (en) 2008-05-06 2014-04-15 Fmc Technologies, Inc. Pump with magnetic bearings
WO2009137321A1 (en) * 2008-05-06 2009-11-12 Fmc Technologies, Inc. Flushing system
CN101430188B (zh) * 2008-11-04 2010-06-09 江苏大学 磁力泵转轴位置在线监测装置和方法
TW201038828A (en) * 2009-04-28 2010-11-01 Assoma Inc Permanent magnetism can pump
FR2947678A1 (fr) * 2009-07-03 2011-01-07 Mecanique Magnetique Sa Machine tournante chemisee et son procede de fabrication
KR101134969B1 (ko) * 2009-11-19 2012-04-09 현대자동차주식회사 전기식 워터 펌프의 고정자 제작 방법
KR101072328B1 (ko) * 2009-11-19 2011-10-11 현대자동차주식회사 전기식 워터 펌프
KR101134968B1 (ko) * 2009-11-19 2012-04-09 현대자동차주식회사 전기식 워터 펌프
KR101072327B1 (ko) * 2009-11-19 2011-10-11 현대자동차주식회사 전기식 워터 펌프
KR101134970B1 (ko) * 2009-11-19 2012-04-09 현대자동차주식회사 전기식 워터 펌프
EP2357374B1 (de) * 2010-01-29 2016-02-17 Levitronix GmbH Magnetische Lagervorrichtung
US8987959B2 (en) * 2010-06-23 2015-03-24 Dresser-Rand Company Split magnetic thrust bearing
US8542800B2 (en) * 2010-09-23 2013-09-24 General Electric Company Asynchronous motor with features creating magnetic field disturbance
CN102654128B (zh) * 2011-03-01 2015-11-25 胡道明 磁悬浮水下电动泵
US20130169074A1 (en) * 2011-12-31 2013-07-04 Sheikh Nayyer Hussain Synchronous relcutance motor for conducting media
TWI494514B (zh) * 2012-05-04 2015-08-01 中原大學 軸向被動式磁浮軸承系統
EP2730785B1 (de) * 2012-11-07 2018-07-25 Pierburg Pump Technology GmbH Elektrische Automobil-Flüssigkeitspumpe
GB2511506A (en) * 2013-03-04 2014-09-10 Hcs Control Systems Ltd Cooled flameproof power supply apparatus
FR3018010B1 (fr) * 2014-02-21 2016-03-11 Skf Magnetic Mechatronics Ensemble modulaire de moteur et paliers magnetiques et procede de fabrication
CN103973025A (zh) * 2014-05-20 2014-08-06 江苏远中电机股份有限公司 水泵用三相异步电动机
BR102014021617B1 (pt) * 2014-09-01 2023-04-11 Mundial S/A Produtos De Consumo Motobomba de mancal flutuante arrefecida por um fluido circulante
JP6474586B2 (ja) * 2014-11-04 2019-02-27 日本ピラー工業株式会社 磁気浮上型ポンプ
DE102016012252A1 (de) * 2016-07-13 2018-01-18 Schwarzer Precision GmbH & Co. KG Pumpenbaugruppe für eine Pumpe, Pumpe und Verfahren zur Verringerung oder Beseitigung von Störgeräuschen und/oder Vibrationen bei Pumpen
US10955000B2 (en) * 2018-11-09 2021-03-23 Bernabe Segura Candelaria Bearingless hub assembly with electromagnetic drive system and associated methods
JP2020128745A (ja) * 2019-02-01 2020-08-27 ホワイト ナイト フルイド ハンドリング インコーポレーテッドWhite Knight Fluid Handling Inc. ロータを支承し、当該ロータを磁気的に軸線方向に位置決めするための磁石を有するポンプ、及びこれに関連する方法
CN113795675B (zh) * 2019-05-24 2024-01-09 株式会社岛津制作所 真空泵及磁轴承一体型马达

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH305818A (de) * 1950-11-02 1955-03-15 Bayer Ag Pumpenaggregat.
US2953993A (en) * 1958-02-12 1960-09-27 Strickland Gerald Pump construction
DE3820003A1 (de) * 1988-06-11 1989-12-21 Grundfos Int Tauchpumpenaggregat
US5324177A (en) * 1989-05-08 1994-06-28 The Cleveland Clinic Foundation Sealless rotodynamic pump with radially offset rotor
FR2701610B1 (fr) * 1993-02-15 1995-04-21 Andre Douanne Dispositif de pivotement pour rotor noyé.
FR2716700B1 (fr) * 1994-02-28 1996-05-15 Mecanique Magnetique Sa Palier magnétique actif à auto-détection de position.
AU5155396A (en) * 1995-04-03 1996-10-23 Wei-Min Zhang Linear motor compressor and its application in cooling syste m
JP3814331B2 (ja) * 1996-03-18 2006-08-30 株式会社ミツバ モータポンプ

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006029399A1 (de) * 2006-06-27 2007-03-01 Cincinnati Extrusion Gmbh Elektromotor mit Axiallager
EP4024675A1 (de) 2020-12-28 2022-07-06 Tomas Pink Single-use rotor mit kurzschlusskäfig

Also Published As

Publication number Publication date
FR2768470A1 (fr) 1999-03-19
WO1999014503A1 (fr) 1999-03-25
US6350109B1 (en) 2002-02-26
JP3419759B2 (ja) 2003-06-23
JP2001516849A (ja) 2001-10-02
EP1015770A1 (de) 2000-07-05
EP1015770B1 (de) 2002-12-11
FR2768470B1 (fr) 2002-02-01
DE69810130D1 (en) 2003-01-23

Similar Documents

Publication Publication Date Title
DE69810130T2 (de) Rotationspumpe mit tauchrotor
EE9800324A (et) Pumbarootor
DE59712162D1 (de) Zentrifugalpumpe
DE19781894T1 (de) Selbstansaugende Kreiselpumpe
DE59804362D1 (de) Rotor mit integraler beschaufelung
DK60197A (da) Centrifugalpumpe med akseltætning
DE69818392D1 (de) Pumpenmotor mit Tauchstator und Tauchrotor
EE9800325A (et) Pumbarootor
DE69922198D1 (de) Zentrifugalpumpe
DE69702776T2 (de) Ölpumpenrotor
DE59906700D1 (de) Kreiselpumpe mit kompensator
DE19780598D2 (de) Flügelzellenpumpe
DE59709468D1 (de) Flügelzellenpumpe
DE29815163U1 (de) Kreiselpumpe
DE29606296U1 (de) Magnetischer Tauchmotor mit verbesserten Rotorblättern
KR970049854U (ko) 수중펌프용 임펠러유니트
DE29520422U1 (de) Selbstansaugende tauchfähige Kreiselpumpe
DE19880474D2 (de) Flügelzellenpumpe
DE29608236U1 (de) Kreiselpumpe
DE59800494D1 (de) Kreiselmotorpumpe mit Gleitringdichtung
ATA24497A (de) Pumpenwelle
DE59912145D1 (de) Kreiselpumpenaggregat
DE29716463U1 (de) Kreiselpumpengehäuse
DE29711534U1 (de) Tauchpumpe
DE29810583U1 (de) Hochtouriges Tauchpumpenaggregat

Legal Events

Date Code Title Description
8364 No opposition during term of opposition