EP2400513A1 - Magnetische Abschirmung für Transformatoren - Google Patents

Magnetische Abschirmung für Transformatoren Download PDF

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Publication number
EP2400513A1
EP2400513A1 EP10167494A EP10167494A EP2400513A1 EP 2400513 A1 EP2400513 A1 EP 2400513A1 EP 10167494 A EP10167494 A EP 10167494A EP 10167494 A EP10167494 A EP 10167494A EP 2400513 A1 EP2400513 A1 EP 2400513A1
Authority
EP
European Patent Office
Prior art keywords
transformer
magnetic shielding
shielding component
magnetic
windings
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Withdrawn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
EP10167494A
Other languages
English (en)
French (fr)
Inventor
Thorsten Steinmetz
Martin Carlen
Jasmin Smajic
Bogdan Cranganu-Cretu
Audrey Kertesz
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.)
ABB Research Ltd Switzerland
ABB Research Ltd Sweden
Original Assignee
ABB Research Ltd Switzerland
ABB Research Ltd Sweden
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 ABB Research Ltd Switzerland, ABB Research Ltd Sweden filed Critical ABB Research Ltd Switzerland
Priority to EP10167494A priority Critical patent/EP2400513A1/de
Publication of EP2400513A1 publication Critical patent/EP2400513A1/de
Withdrawn legal-status Critical Current

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/08Cooling; Ventilating
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/34Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36Electric or magnetic shields or screens
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/34Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36Electric or magnetic shields or screens
    • H01F27/361Electric or magnetic shields or screens made of combinations of electrically conductive material and ferromagnetic material
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/34Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36Electric or magnetic shields or screens
    • H01F27/366Electric or magnetic shields or screens made of ferromagnetic material

Definitions

  • the invention relates to magnetic shielding of transformers.
  • the invention relates to a transformer with at least one magnetic shielding arrangement and to a magnetic shielding component adapted for the transformer with at least one magnetic shielding arrangement.
  • the existence of the stray magnetic flux may be inevitable and cannot be completely prevented just by means of careful and inventive design.
  • the stray magnetic field produced by the windings may have strongest values in the region around the ends of the windings which are very close to the clamps used to press the core laminations. This yields a high level of eddy current losses in the clamps and consequently their overheating.
  • the losses in the clamps reduce the efficiency of the transformer, increase the cost of the transformer over its entire lifetime, create potential hazardous local overheating, and contribute to increasing the oil temperature of the transformer which reduces its cooling capabilities.
  • Dry transformers are environment-friendly, low maintenance transformers, which provide a very low flammability risk, and therefore are often used as distribution transformers, e.g. in public, industrial and residential buildings, power plants or on board of ships. Because of possible influences to humans or technical devices, the magnetic stray field emitted during operation of such dry transformers may have to be very low. A few countries have legal restrictions for the maximum values of the magnetic flux density at work places, living/sleeping rooms, hospitals, schools, etc. In Switzerland for example, this value is 1 ⁇ T.
  • the patent application JP-11283848-A describes a magnetic shielding arrangement in a transformer, wherein a magnetic shield is distributed along the yoke of the transformer.
  • the patent DE 44 32 739 B4 depicts an inductive electrical component with a cover of ferromagnetic material.
  • This obj ect is achieved by a transformer with at least one magnetic shielding arrangement, and by a magnetic shielding component adapted for the transformer according to the independent claims. Further embodiments are evident from the dependent claims.
  • a transformer with at least one magnetic shielding arrangement for shielding the magnetic stray field of the transformer is provided.
  • a first magnetic shielding component is arranged at a first end region of windings of the transformer such that a magnetic stray field and/or stray losses caused by the windings of the transformer during operation of the transformer are reduced.
  • the first magnetic shielding component comprises at least one recess adapted for cooling the transformer.
  • the first magnetic shielding component which may be a separate component, for example a plate with a recess, may be arranged between one of more than one windings of the transformer and the yoke or shielding clamp of the transformer.
  • the winding(s) may have corresponding duct(s).
  • Such a magnetic shielding arrangement may protect the clamps from the stray field produced by transformer windings and may prevent a magnetic stray field from emitting to the surrounding environment. Humans may be protected from the magnetic stray field emitted during operation of the transformer, for example.
  • the at least one magnetic shielding arrangement may provide a (passive) magnetic shielding for dry-type transformers reducing the magnetic stray field emitted by the dry-type transformer to the environment.
  • Such a transformer with at least one magnetic shielding arrangement may provide for a minimum value of induced eddy current losses in core clamps of a transformer such as a power transformer, for example, a minimum hindrance of oil circulation in vertical direction of a transformer and at the bottom and top of the windings of the transformer, for a reduction of material, and thus for minimum material costs.
  • the clamps of the transformers may be protected by the magnetic shielding arrangement with magnetic shields form the stray fields produced by the transformer windings.
  • the recess may be a slot and the magnetic shielding arrangement and/or first component may of grating or net type.
  • a transformer with such a magnetic shielding arrangement may provide that electrical fields remain below critical values and allow safe operation of the transformer.
  • the first magnetic shielding component may be made of a non-conductive but highly magnetic permeable material which may be relatively easy produced by rolling and pressing tiny oxidized films of highly permeable iron.
  • the oxidized layers may prevent the conduction of electrical current in the desired direction, for example, the direction of induces eddy currents, achieving the required non-conductive property.
  • long magnetic shunts with an arbitrary shape of their cross-section may be produced that can be afterwards combined in a shunt system of a suitable shape.
  • the magnetic shields may operate far from the saturation regime, such that the stray magnetic fields may be directed through them towards the core and hence bypassing the clamps.
  • Such a transformer with at least one magnetic shielding arrangement may advantageously improve the circulation of oil for a high bar transformer along with the cooling of the cores.
  • a rounding of the edges of the first magnetic shielding component may help to decrease distances and place the first magnetic shielding component as close as possible to the windings.
  • the first magnetic shielding component may be arranged below one or more of windings and corresponding ducts.
  • the magnetic shielding arrangement of the transformer may further comprise a second magnetic shielding component that is arranged at a second end region of the windings of the transformer.
  • the second magnetic shielding component may be arranged above one or more of windings and corresponding ducts.
  • the magnetic shielding arrangement may have the form of a shielding box surrounding the whole transformer.
  • the shields/walls of the box may comprise a highly permeable plate alongside the transformer.
  • a number of plates may be positioned at all or some sides of the transformer.
  • the shielding box can be formed by a frame built of electrically high-conducting but not magnetic material such as copper or aluminium.
  • the frame may have one or more traverses that may be arranged horizontally and/or vertically in a frame built.
  • the frame built may combined, wherein the interstices of the frame are filled with one of the materials selected from the group comprising high-permeable and electrically low-conductive material, laminated core steel such as silicon core steel and amorphous core steel, and ferrite material.
  • the frame may be suitable to mechanically clamp the laminated material together.
  • Layer plates may be used to build the box comprising material comprising high-permeable and electrically low-conductive material, laminated core steel such as silicon core steel and amorphous core steel, ferrite material, and electrically high-conductive and non-magnetic material.
  • the layers with laminated material may have different lamination directions. In a most, there may be either high-permeable or electrically high-conductive material. There may be either high-permeable or electrically high-conductive material. There may be air-filled gaps in-between the individual layers.
  • the shields/walls may be integrated in an enclosure of the transformer.
  • the magnetic shielding components may be arranged in such a way, that they are at least partly surrounding the busbars of the transformer.
  • the first magnetic shielding component is arranged between the windings and a core clamp supporting a yoke of the transformer for protecting the core clamp from a magnetic stray field caused by windings of the transformer during operation.
  • the first magnetic shielding component comprises a first recess to fit the first magnetic shielding component to a core limb of the transformer such that part of a cross-sectional area of a winding of the transformer perpendicular to the axis of the core limb is not covered by the first magnetic shielding component such that a cooling flow in an axial direction through the first magnetic shielding component is provided.
  • the first recess may be in the middle of the first magnetic shielding component surrounded by magnetic shielding material which may built a frame form.
  • the first recess may on the side of the first magnetic shielding component that faces the core of the transformer.
  • the first recess may have a circular, a rectangular, and a polygonal form, or a combination thereof.
  • the first magnetic shielding component comprises a second recess in a direction parallel to a yoke of the transformer such that a cooling flow in an axial direction through the first magnetic shielding component in an area of the outer windings of the transformer is provided.
  • Such a second recess may provide for a better oil circulation, a better cooling of the clamp and the oil, and a shield material reduction.
  • the second recess may have a circular, a rectangular, and a polygonal form, or a combination thereof.
  • the first magnetic shielding component comprises a third recess in a direction away from the core of the transformer in the direction opposite of the first recess such that a cooling flow in an axial direction through the first magnetic shielding component in an area outside of the windings of the transformer is provided.
  • the third recess may have a circular, a rectangular, or a polygonal form, or a combination thereof.
  • the first magnetic shielding component is essentially planar.
  • a planar first magnetic shielding component may have a form of a plate.
  • the plates may have a shape selected from the group comprising a rectangular, a polygonal, a circular, and a semi-circular shape, or a combination thereof.
  • the first magnetic shielding component further comprises an extension that is arranged at the first magnetic shielding component at the frame of the first recess in a direction towards the core of the transformer for arranging the first magnetic shielding component at the core of the transformer.
  • the extension extends at least partly in a first recess.
  • the at least one recess is adapted for reducing eddy currents in the clamps that occur during operation of the transformer.
  • the first magnetic shielding component comprises extensions in a direction parallel to a core of the transformer covering at least a part of the windings of the transformer such that the first magnetic shielding component has a trough-like form for redirecting the magnetic stray flux caused by the windings of the transformer during operation of the transformer.
  • the first magnetic shielding component is formed by a plurality of separate magnetic shielding elements such that a ring shaped first magnetic shielding component is provided.
  • the magnetic shielding elements forming the first magnetic shielding component have a form selected from the group consisting of a rectangular frame, a circular frame, a polygonal frame, a semi-circular frame with an inner first radius and an outer second radius, a rectangular form, a circular form, a polygonal form, an L-form, a U-form, or may have the form of a shielding box surrounding the transformer.
  • the first magnetic shielding component comprises a magnetically high-permeable and electrically low-conductive material.
  • Such a first magnetic shielding component may be constructed from rolled and pressed oxidized films of high-permeable iron, whose laminations are pressed parallel to the magnetic stray flux of the core of the transformer.
  • the oxidation layers may prevent the conduction of electric currents in the direction of the induced eddy currents achieving the required non-conductive property.
  • the first magnetic shielding component comprises an electrically high-conducting and non-magnetic material such as copper or aluminium, a laminated core steel such as silicon core steel and amorphous core steel, and ferrite material.
  • the transformer is a power transformer.
  • a magnetic shielding arrangement of a power transformer may provide for a protection of the clamps, reduce the eddy current losses in the clamps, and leave enough space for the flow of oil, thereby providing the necessary cooling.
  • the transformer is a dry transformer.
  • the magnetic shielding component is adapted for a transformer according to any one of the preceding exemplary embodiments.
  • a method of reducing the magnetic stray field caused by windings of a transformer during operation is provided with the step of shielding the magnetic stray field by a magnetic shielding arrangement.
  • the first magnetic shielding component of the magnetic shielding arrangement is arranged in a first end region of the windings of the transformer.
  • the use of a magnetic shielding arrangement for reducing the magnetic stray field of a transformer and/or a power transformer caused by the windings of a dry transformer and/or the power transformer during operation is provided.
  • Fig. 1 depicts a transformer 100 comprising a magnetic shielding arrangement 101 with a first magnetic shielding component 102 and a second magnetic shielding component 103.
  • the first magnetic shielding component 102 is arranged in a first end region 104 of windings 106 of the transformer 100 and the second magnetic shielding component 103 is arranged at a second end region 105 of windings 106 of the transformer 100 such that a magnetic stray field and/or stray losses caused by the windings 106 of the transformer 100 during operation of the transformer 100 is reduced.
  • the edges of the first magnetic shielding component 102 and the second magnetic shielding component 103 are rounded.
  • FIG. 2A schematically depicts a first magnetic shielding component 102 or a second magnetic shielding component 103 with rounded edges being essentially planar, with a recess 201 essentially in the middle of the planar first or second magnetic shielding component 102, 103.
  • Fig. 2B depicts the first or second magnetic shielding component 102, 103 of Fig. 2A with extensions 202, 203 being arranged at the first or second magnetic shielding component 102, 103 at a frame of the first recess 201 in an upright position, possibly in a direction towards the core of a transformer, when the first or second magnetic shielding component 102, 103 is installed.
  • the extensions 202, 203 may extend in a direction of the first recess 201 at a blunt angle compared to the plane of the first or second magnetic shielding component 102, 103 or at a sharp angle to a core axis of a transformer.
  • the recess 201 of the first or second magnetic shielding component 102, 103 may fit to a core of a transformer.
  • Fig. 3A schematically depicts the first or second magnetic shielding component 102, 103 with extensions 202, 203 according to Fig. 2B , with the difference that the first or second magnetic shielding component 102, 103 is splitted into several magnetic shielding elements 301, 302, 303 forming the first or second magnetic shielding component 102, 103.
  • the circulation of the cooling fluid between the shielding elements 301, 302, 303 is provided and the cooling flux in axial direction of the the core limbs 402 is improved.
  • Fig. 3B schematically shows the first or second magnetic shielding component 102, 103 according to Fig. 3A with the difference, that each magnetic shielding element 301, 302, 303 comprises an extension 305 in a direction parallel to a core limb axis of a transformer fitting through the recess 201.
  • the extensions 305 are adapted to cover at least a part of the windings of the transformer such that the first or second magnetic shielding component 102, 103 has a trough-like form for deflecting magnetic stray flux caused by the windings of the transformer during operation of the transformer.
  • FIG. 3C schematically shows the first or second magnetic shielding component 102, 103 of Fig. 3B , with the difference each magnetic shielding element 301, 302, 303 comprises a slot-like second recess 304 in parallel to the first recess 201.
  • Fig. 4 schematically shows a perspective view of a transformer 100 with a magnetic shielding arrangement 101 comprising a first magnetic shielding component 102 being arranged at a first end region 104 of the windings 106 of the transformer and a shield/wall 401 arranged at one side of the transformer 100 parallel to the core limbs 402 of the transformer.
  • the magnetic shielding component 102 and the shield/wall 401 which may comprise a high-permeable plate 401 reducing a magnetic stray field and/or stray losses caused by the windings 106 of the transformer 100 during operation of the transformer 100.
  • the magnetic shielding arrangement 101 may also have the form of a shielding box comprising a plurality of shields/walls 401 surrounding the whole transformer 100. There may be up to six shields/walls 401 positioned at all sides of the transformer 100.
  • Fig. 5A schematically shows a cross-sectional view of the shield 401 of Fig. 4 comprising a layered plate 501 comprising layers 502, 503 which may comprise laminated material possibly having different lamination directions.
  • the layered plate 501 may comprise materials selected from the group comprising high-permeable and electrically low-conductive material, laminated core steel, such as silicon core steel and amorphous core steel, and ferrite material, and electrically high-conductive and non-magnetic material.
  • the first layer 502 can comprise high-permeable material.
  • the second layer 503 can comprise electrically high-conductive material. There may be gaps which may be air-filled in-between the first and the second layers 502, 503.
  • Fig. 5B schematically shows several layered plates 501 according to Fig. 5A forming a shield 401.
  • Fig. 6A schematically shows a frame build 601 of shields according to Fig. 5A or Fig. 5B for magnetic shielding of a transformer, comprising one frame.
  • Fig. 6B shows the frame build 601 of Fig. 6A with a horizontal traverse 602 in the middle of the frame.
  • Fig. 6C shows the frame build 601 of Fig. 6B added by a vertical traverse 602.
  • Fig. 6D schematically shows the frame build of Fig. 6A with three vertical traverses 602 and three horizontal traverses 602 in equi-spaced distances arranged inside the frame build 601.
  • Fig. 7 schematically shows a perspective view of a part of a transformer 100 with three phases with three core limbs 402 possibly surrounded by regulation windings 800, low-voltage windings 801 and high-voltage windings 802 in order to efficiently energize the core limbs 402 and establish the magnetic coupling essential for the transformer's functioning. Due to imperfections in the interaction between the windings 800, 801, 802 and the core limbs 402 a certain level of stray flux is always present penetrating the structural components of the transformer such as the core clamps 701 which press the core laminations in order to ensure the core's stability. A yoke 702 is connecting the core limbs 402.
  • Fig. 8A shows the transformer of Fig. 7 with the difference, that a first or second magnetic shielding component 102, 103 is provided comprising three separate magnetic shielding elements 301, 302, 303, wherein the magnetic shielding elements 301, 302, 303 are arranged between the windings 800, 801, 802 and the clamp 701.
  • Fig. 8B schematically shows a cross-section of one core limb 402 of the transformer 100 of Fig. 8A with windings 800, 801, 802 surrounding the core limb 402.
  • the first or second magnetic shielding component 102, 103 comprises of a first magnetic shielding element 804 and a second magnetic shielding elements 805, each magnetic shielding element 804, 805 comprising a recess 201 with an extension 803.
  • Fig. 9A schematically shows a perspective view of the transformer 100 of Fig. 8A , with the difference, that the first or second magnetic shielding component 102, 103 comprises three separate magnetic shielding elements 301, 302, 303, each comprising a first magnetic shielding element 804 and a second magnetic shielding element 805 and a first, second and third recess 201, 901, 904 with extensions 803, 902.
  • the second and the third recess 901, 904 of the neighbouring shielding components 102, 103 provide a cooling flux between neighbouring coils of the transformer 100 in axial direction of the core limb 402.
  • Fig. 9B schematically shows a cross-sectional view of one of the core limbs 402 of Fig. 9A , wherein each of the first and second magnetic shielding elements 804, 805 comprises a first recess 201 and three extensions 803 to fit the first and second magnetic shielding elements 804, 805 to the core limb 402 of the transformer.
  • the magnetic shielding component, respectively the magnetic shielding elements 804, 805 further comprise a second recess 901 in a direction parallel to the yoke 702 comprising three extensions 902.
  • the first or second magnetic shielding component 102, 103 and respectively each magnetic shielding elements 804, 805, further comprises a third recess 904 in a direction away from the core limb 402 of the transformer 100 in a direction opposite to the first recess 201.
  • Fig. 10A schematically shows a perspective view of the transformer 100 of Fig. 9A with a different geometric form of the first and second magnetic shielding elements 804, 805.
  • Fig. 10B schematically shows a cross-section of one core limb 402 of the transformer according to Fig. 10A , each magnetic shielding element 804, 805 having a first recess 201 with an extension 803, and a second recess 901 with three extensions 902 in the same directions as depicted in Fig. 9B but with a different geometry concerning the recesses 201, 901 and the extensions 803, 902.
  • Fig. 11A schematically shows a perspective view of the transformer 100 of Fig. 9A with a different geometric form of the first and second magnetic shielding elements 804, 805.
  • Fig. 11B schematically shows a cross-section of one core limb 402 of the transformer according to Fig. 11A , each magnetic shielding element 804, 805 comprising a first recess 201 with an extension 803 and a second recess 901 with three extensions 902 according to Fig. 10B , but with a different geometry concerning the first recess 201 and the second recess 901 compared to the geometry of Fig. 10B .
  • Fig. 12A schematically shows a perspective view of the transformer 100 of Fig. 7 , with the difference, that a first or second magnetic shielding component 102, 103 with separate magnetic shielding elements 301, 302, 303 is provided, wherein each magnetic shielding element 301, 302, 303 is arranged between the clamps 701 and the windings 801, 802, 803 surrounding the core limbs 402 of the transformer.
  • Each of the plurality of magnetic shielding elements 301 has a semi-circular shape, being arranged between the regulation windings 800 and part of the high-voltage windings 802 of each core limb 402 of a transformer 100.
  • Fig. 12B schematically shows a cross-section of one core limb 402 of the transformer 100 with one magnetic shielding element 301, 302, 303 according to Fig. 12A .

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Regulation Of General Use Transformers (AREA)
EP10167494A 2010-06-28 2010-06-28 Magnetische Abschirmung für Transformatoren Withdrawn EP2400513A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP10167494A EP2400513A1 (de) 2010-06-28 2010-06-28 Magnetische Abschirmung für Transformatoren

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP10167494A EP2400513A1 (de) 2010-06-28 2010-06-28 Magnetische Abschirmung für Transformatoren

Publications (1)

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EP2400513A1 true EP2400513A1 (de) 2011-12-28

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014095016A1 (de) * 2012-12-21 2014-06-26 Sew-Eurodrive Gmbh & Co. Kg Lagersystem für objekte, insbesondere container, und spannungsversorgungseinheit für ein objekt
JP2014216524A (ja) * 2013-04-26 2014-11-17 株式会社日立製作所 静止誘導電器
US9640315B2 (en) 2013-05-13 2017-05-02 General Electric Company Low stray-loss transformers and methods of assembling the same
WO2018091730A1 (en) * 2016-11-21 2018-05-24 Siemens Aktiengesellschaft Magnetic field loss reduction member for electrical device
JP2018107224A (ja) * 2016-12-26 2018-07-05 株式会社日立産機システム 静止誘導電器

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5632706A (en) * 1979-08-27 1981-04-02 Hitachi Ltd Stationary inductive electric machine
JPS57152116A (en) * 1981-03-14 1982-09-20 Hitachi Ltd Stationary induction electric apparatus
JPS58139415A (ja) * 1982-02-15 1983-08-18 Hitachi Ltd 静止誘導電器
JPS6098609A (ja) * 1983-11-02 1985-06-01 Toshiba Corp 静止誘導電器
JPH11283848A (ja) 1998-03-27 1999-10-15 Hitachi Ltd 静止誘導電器
DE4432739B4 (de) 1994-09-14 2005-03-17 Epcos Ag Induktives elektrisches Bauteil

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5632706A (en) * 1979-08-27 1981-04-02 Hitachi Ltd Stationary inductive electric machine
JPS57152116A (en) * 1981-03-14 1982-09-20 Hitachi Ltd Stationary induction electric apparatus
JPS58139415A (ja) * 1982-02-15 1983-08-18 Hitachi Ltd 静止誘導電器
JPS6098609A (ja) * 1983-11-02 1985-06-01 Toshiba Corp 静止誘導電器
DE4432739B4 (de) 1994-09-14 2005-03-17 Epcos Ag Induktives elektrisches Bauteil
JPH11283848A (ja) 1998-03-27 1999-10-15 Hitachi Ltd 静止誘導電器

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014095016A1 (de) * 2012-12-21 2014-06-26 Sew-Eurodrive Gmbh & Co. Kg Lagersystem für objekte, insbesondere container, und spannungsversorgungseinheit für ein objekt
CN104812683A (zh) * 2012-12-21 2015-07-29 索尤若驱动有限及两合公司 用于物体、特别是容器的仓储系统,和用于物体的供电单元
CN104812683B (zh) * 2012-12-21 2017-04-05 索尤若驱动有限及两合公司 用于物体、特别是容器的仓储系统,和用于物体的供电单元
JP2014216524A (ja) * 2013-04-26 2014-11-17 株式会社日立製作所 静止誘導電器
US9640315B2 (en) 2013-05-13 2017-05-02 General Electric Company Low stray-loss transformers and methods of assembling the same
US10153085B2 (en) 2013-05-13 2018-12-11 Abb Schweiz Ag Low stray-loss transformers and methods of assembling the same
WO2018091730A1 (en) * 2016-11-21 2018-05-24 Siemens Aktiengesellschaft Magnetic field loss reduction member for electrical device
JP2018107224A (ja) * 2016-12-26 2018-07-05 株式会社日立産機システム 静止誘導電器

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