EP0225241A1 - Coreless-type high-frequency current transformer - Google Patents

Coreless-type high-frequency current transformer Download PDF

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Publication number
EP0225241A1
EP0225241A1 EP86402512A EP86402512A EP0225241A1 EP 0225241 A1 EP0225241 A1 EP 0225241A1 EP 86402512 A EP86402512 A EP 86402512A EP 86402512 A EP86402512 A EP 86402512A EP 0225241 A1 EP0225241 A1 EP 0225241A1
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EP
European Patent Office
Prior art keywords
central part
mandrel
wound
transformer according
sides
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Granted
Application number
EP86402512A
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German (de)
French (fr)
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EP0225241B1 (en
Inventor
Noel Guais
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General Electric CGR SA
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General Electric CGR SA
Thomson CGR
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Publication of EP0225241A1 publication Critical patent/EP0225241A1/en
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Publication of EP0225241B1 publication Critical patent/EP0225241B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/02—Casings
    • H01F27/027—Casings specially adapted for combination of signal type inductors or transformers with electronic circuits, e.g. mounting on printed circuit boards
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2866—Combination of wires and sheets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase ac
    • H01F38/28—Current transformers
    • H01F38/30—Constructions

Definitions

  • the present invention relates to a high frequency air current transformer.
  • transformers devoid of magnetic cores for medical magnetic resonance imaging devices generally known by the abbreviation MRI.
  • MRI magnetic resonance imaging devices
  • the known production techniques for current transformers lead to the use of magnetic ferrite circuits to obtain good magnetic coupling between the primary and secondary windings of the transformers.
  • These production techniques naturally go against the design requirements of MRI devices because the presence of a ferrite intensity transformer can naturally cause deformation of the field lines of the magnet of MRI devices.
  • the object of the invention is to overcome the aforementioned drawbacks.
  • the subject of the invention is a high frequency air intensity transformer, characterized in that it comprises: on the one hand, a primary winding formed by a conductive strip wound on an insulating mandrel comprising, a rectangular central part whose long sides extend in a first direction, and two parts located at the ends of the central part of slightly near rectangular, the long sides of which extend in a second and a third direction in opposite directions, the length of the central part measured in the first direction being determined to allow the two ends to have the directions of their long collinear sides two by two when the central part, considered in the first direction is wound on the mandrel and in that the two angles formed at the crossing of the edges of the parts situated at the ends with the edges adjacent to the long sides of the part central, are truncated to avoid overlapping of the two ends when the central part is wound on the mandrel, and on the other hand, a secondary winding with N contiguous turns of enameled wire wound above the conductive strip.
  • the main advantage of the invention is that it allows the production of high frequency air intensity transformers, in which maximum coupling can be obtained between the primary and secondary windings, which thus partially compensates for the absence of magnetic circuit. .
  • the particular shape of the conductive strip which avoids the overlapping of the ends of the coil, makes it possible to obtain maximum efficiency of the latter over a full turn, while dispensing with the establishment of layers of insulation between ends which would disadvantage the quality of the magnetic coupling between primary and secondary.
  • the shape given to the primary turn guarantees a winding of constant thickness of the primary and secondary windings around the mandrel and thus allows the best coupling to be obtained.
  • the current transformer according to the invention which is shown in Figure 1 comprises a mandrel 1 made of plastic, or any other equivalent insulating material, on which are successively wound, a primary winding 2, a metal screen 3 and a secondary winding 4.
  • the primary winding 2 is constituted by a strip which is cut from a sheet of metal foil according to the S-shaped outline shown in FIG. 2, before being wound on the mandrel 1.
  • the strip shown in FIG. 2 includes a central part 5 of roughly rectangular shape and two other parts 6 and 7 of also roughly rectangular shapes which extend in two directions opposite one another at the ends of the central part. In FIG. 2, directions of the long sides 61, 62 on the one hand, and 71, 72 on the other hand, rectangular parts 6 and 7 are perpendicular to the direction of the long sides 51 and 52 of the rectangle forming the central part 5.
  • the length L of the long sides 51, 52 of the central part is determined to allow the ends 6 and 7 to be in extension of one another when the central part 5 is wound on the mandrel 1 and the angles formed by the adjacent edges of the corresponding lamella on the one hand, at the sides 52, 62 and on the other hand, at the sides 51, 71 are truncated in the same direction, at 45 ° for example from the direction of the sides 51 and 52, for form the edges 8 and 9 of FIG. 2, and avoid overlapping of the ends of the central part 5 when it is wound on the mandrel 1 in the manner shown in FIG. 3.
  • the screen 3 which is represented in FIG. 4 makes it possible to carry out the electrostatic shielding of the transformer and to limit the parasitic capacities between primary and secondary.
  • the isolations between the screen 3 and the primary and secondary windings are carried out in a known manner using one or more layers of PTFE sheets (abbreviation of polytetrafluoroethylene) or of adhesive paper.

Abstract

Le transformateur comprend un enroulement primaire (2) formé par une lamelle conductrice enroulée sur un mandrin isolant (1) comportant une partie centrale (5), deux parties (6, 7) situées aux extrémités de la partie centrale (5) de forme à peu près rectangulaire dont les grands côtés s'étendent selon une deuxième et une troisème direction de sens opposés l'une à l'autre. La longueur (L) de la partie centrale mesurée selon la première direction est déterminée pour permettre aux deux extrémités (6, 7) d'avoir les directions de leurs grands côtés colinéaires deux à deux lorsque la partie centrale (5) est enroulée sur le mandrin (1). Les deux angles formés au croisement des bords des parties situées aux extrémités avec les bords adjacents aux grands côtés de la partie centrale (5), sont tronqués pour éviter le chevauchement des deux extrémités (6, 7) lorsque la partie centrale (5) est enroulée sur le mandrin (1). Application : appareils médicaux d'imagerie.The transformer comprises a primary winding (2) formed by a conductive strip wound on an insulating mandrel (1) comprising a central part (5), two parts (6, 7) located at the ends of the central part (5) roughly rectangular, the long sides of which extend in a second and a third direction in opposite directions. The length (L) of the central part measured in the first direction is determined to allow the two ends (6, 7) to have the directions of their long collinear sides in pairs when the central part (5) is wound on the mandrel (1). The two angles formed at the crossing of the edges of the parts situated at the ends with the edges adjacent to the long sides of the central part (5), are truncated to avoid the overlapping of the two ends (6, 7) when the central part (5) is wound on the mandrel (1). Application: medical imaging devices.

Description

La présente invention concerne un transformateur d'intensite haute fréquence à air.The present invention relates to a high frequency air current transformer.

Elle s'applique plus particulièrement à la fabrication de transfor­mateurs dépourvus de noyaux magnétiques pour les appareils médicaux d'imagerie par résonance magnétique généralement connus sous l'abrévia­tion IRM. On sait qu'il est souhaitable pour obtenir un bon fonctionnement de ces appareils de supprimer les causes de déformations des lignes de champs de l'aimant entrant dans leur constitution. Or aux fréquences de fonctionnement de ceux-ci, 6 à 30 MHz, les techniques de réalisation connues des transformateurs d'intensité conduisent à utiliser des circuits magnétiques en ferrite pour obtenir un bon couplage magnétique entre enroulements primaire et secondaire des transformateurs. Ces techniques de réalisation vont naturellement à l'encontre des exigences de conception des appareils IRM car la présence d'un transformateur d'intensité en ferrite peut naturellement provoquer des déformations des lignes des champs de l'aimant des appareils IRM.It more particularly applies to the manufacture of transformers devoid of magnetic cores for medical magnetic resonance imaging devices generally known by the abbreviation MRI. We know that it is desirable to obtain proper operation of these devices to eliminate the causes of deformation of the field lines of the magnet entering into their constitution. However, at their operating frequencies, 6 to 30 MHz, the known production techniques for current transformers lead to the use of magnetic ferrite circuits to obtain good magnetic coupling between the primary and secondary windings of the transformers. These production techniques naturally go against the design requirements of MRI devices because the presence of a ferrite intensity transformer can naturally cause deformation of the field lines of the magnet of MRI devices.

Le but de l'invention est de pallier les inconvénients précités.The object of the invention is to overcome the aforementioned drawbacks.

A cet effet, l'invention a pour objet, un transformateur d'intensité haute fréquence à air, caractérisé en ce qu'il comprend :
d'une part, un enroulement primaire formé par une lamelle conductrice enroulée sur un mandrin isolant comportant, une partie centrale rectangulaire dont les grands côtés s'étendent selon une première direction, et deux parties situées aux extrémités de la partie centrale de forme à peu près rectangulaire dont les grands côtés s'étendent selon une deuxième et une troisième direction de sens opposés l'une à l'autre, la longueur de la partie centrale mesurée selon la première direction étant déterminée pour permettre aux deux extrémités d'avoir les directions de leurs grands côtés colinéaires deux à deux lorsque la partie centrale, considérée selon la première direction est enroulée sur le mandrin et en ce que les deux angles formés au croisement des bords des parties situées aux extrémités avec les bords adjacents aux grands côtés de la partie centrale, sont tronqués pour éviter le chevauchement des deux extrémités lorsque la partie centrale est enroulée sur le mandrin,
et d'autre part, un enroulement secondaire à N spires jointives de fil émaillé enroulées au-dessus de la lamelle conductrice.To this end, the subject of the invention is a high frequency air intensity transformer, characterized in that it comprises:
on the one hand, a primary winding formed by a conductive strip wound on an insulating mandrel comprising, a rectangular central part whose long sides extend in a first direction, and two parts located at the ends of the central part of slightly near rectangular, the long sides of which extend in a second and a third direction in opposite directions, the length of the central part measured in the first direction being determined to allow the two ends to have the directions of their long collinear sides two by two when the central part, considered in the first direction is wound on the mandrel and in that the two angles formed at the crossing of the edges of the parts situated at the ends with the edges adjacent to the long sides of the part central, are truncated to avoid overlapping of the two ends when the central part is wound on the mandrel,
and on the other hand, a secondary winding with N contiguous turns of enameled wire wound above the conductive strip.

L'invention a principalement pour avantage qu'elle permet la réalisation de transformateurs d'intensité haute fréquence à air, dans lesquels un couplage maximal peut être obtenu entre les enroulements primaire et secondaire, ce qui compense ainsi en partie l'absence de circuit magnétique.The main advantage of the invention is that it allows the production of high frequency air intensity transformers, in which maximum coupling can be obtained between the primary and secondary windings, which thus partially compensates for the absence of magnetic circuit. .

D'autre part, la forme particulière de la lamelle conductrice qui évite le chevauchement des extrémités de la spire, permet d'obtenir une efficacité maximale de celle-ci sur un tour complet, tout en dispensant de la mise en place de couches d'isolements entre extrémités qui défavorise­raient la qualité du couplage magnétique entre primaire et secondaire.On the other hand, the particular shape of the conductive strip which avoids the overlapping of the ends of the coil, makes it possible to obtain maximum efficiency of the latter over a full turn, while dispensing with the establishment of layers of insulation between ends which would disadvantage the quality of the magnetic coupling between primary and secondary.

Egalement, la forme donnée à la spire primaire garantit un bobinage d'épaisseur constante des enroulements primaire et secondaire autour du mandrin et permet ainsi l'obtention du meilleur couplage.Also, the shape given to the primary turn guarantees a winding of constant thickness of the primary and secondary windings around the mandrel and thus allows the best coupling to be obtained.

D'autres caractéristiques et avantages de l'invention apparaîtront également à l'aide de la description qui va suivre faite au regard des dessins annexés qui représentent :

  • - la figure 1 une vue en perspective d'un transformateur d'inten­sité selon l'invention ;
  • - la figure 2 un mode de réalisation vu en plan d'une lamelle conductrice pour l'obtention de l'enroulement primaire du transformateur selon l'invention ;
  • - la figure 3 une représentation d'une lamelle conductrice montée sur un mandrin d'un transformateur selon l'invention ;
  • - la figure 4 un mode de réalisation de l'écran d'isolement du transformateur représenté à la figure 1.
Other characteristics and advantages of the invention will also appear with the aid of the description which follows, given with regard to the appended drawings which represent:
  • - Figure 1 a perspective view of an intensity transformer according to the invention;
  • - Figure 2 an embodiment seen in plan of a conductive strip for obtaining the primary winding of the transformer according to the invention;
  • - Figure 3 a representation of a conductive strip mounted on a mandrel of a transformer according to the invention;
  • - Figure 4 an embodiment of the isolation screen of the transformer shown in Figure 1.

Le transformateur d'intensité selon l'invention qui est représenté à la figure 1 comprend un mandrin 1 en matière plastique, ou tout autre matériau isolant équivalent, sur lequel sont enroulés successivement, un enroulement primaire 2, un écran métallique 3 et un enroulement secon­daire 4. L'enroulement primaire 2 est constitué par une lamelle qui est découpée dans une feuille de clinquant métallique selon le tracé en forme de S représenté à la figure 2, avant d'être enroulé sur le mandrin 1. La lamelle représentée à la figure 2 comprend, une partie centrale 5 de forme à peu près rectangulaire et deux autres parties 6 et 7 de formes également à peu près rectangulaires qui s'étendent selon deux directions opposées l'une à l'autre aux extrémités de la partie centrale. Sur la figure 2, des directions des grands côtés 6₁ , 6₂ d'une part, et 7₁ , 7₂ d'autre part, des parties rectangulaires 6 et 7 sont perpendiculaires à la direction des grands côtés 5₁ et 5₂ du rectangle formant la partie centrale 5.The current transformer according to the invention which is shown in Figure 1 comprises a mandrel 1 made of plastic, or any other equivalent insulating material, on which are successively wound, a primary winding 2, a metal screen 3 and a secondary winding 4. The primary winding 2 is constituted by a strip which is cut from a sheet of metal foil according to the S-shaped outline shown in FIG. 2, before being wound on the mandrel 1. The strip shown in FIG. 2 includes a central part 5 of roughly rectangular shape and two other parts 6 and 7 of also roughly rectangular shapes which extend in two directions opposite one another at the ends of the central part. In FIG. 2, directions of the long sides 6₁, 6₂ on the one hand, and 7₁, 7₂ on the other hand, rectangular parts 6 and 7 are perpendicular to the direction of the long sides 5₁ and 5₂ of the rectangle forming the central part 5.

La longueur L des grands côtés 5₁ , 5₂ de la partie centrale est déterminée pour permettre aux extrémités 6 et 7 d'être en prolongement l'une de l'autre lorsque la partie centrale 5 est enroulée sur le mandrin 1 et les angles formés par les bords adjacents de la lamelle correspondant d'une part, aux côtés 5₂ , 6₂ et d'autre part, aux côtés 5₁ , 7₁ sont tronqués selon une même direction, à 45° par exemple de la direction des côtés 5₁ et 5₂ , pour former les bords 8 et 9 de la figure 2, et éviter le chevauchement des extrémités de la partie centrale 5 lorsqu'elle est enroulée sur le mandrin 1 de la manière représentée la figure 3.The length L of the long sides 5₁, 5₂ of the central part is determined to allow the ends 6 and 7 to be in extension of one another when the central part 5 is wound on the mandrel 1 and the angles formed by the adjacent edges of the corresponding lamella on the one hand, at the sides 5₂, 6₂ and on the other hand, at the sides 5₁, 7₁ are truncated in the same direction, at 45 ° for example from the direction of the sides 5₁ and 5₂, for form the edges 8 and 9 of FIG. 2, and avoid overlapping of the ends of the central part 5 when it is wound on the mandrel 1 in the manner shown in FIG. 3.

L'écran 3 qui est représenté à la figure 4 permet d'effectuer le blindage électrostatique du transformateur et de limiter les capacités parasites entre primaire et secondaire. Les isolements entre l'écran 3 et les enroulements primaire et secondaire sont réalisés de façon connue à l'aide d'une ou plusieurs couches de feuilles de PTFE (abréviation de polytétrafluoréthylène) ou de papier adhésif.The screen 3 which is represented in FIG. 4 makes it possible to carry out the electrostatic shielding of the transformer and to limit the parasitic capacities between primary and secondary. The isolations between the screen 3 and the primary and secondary windings are carried out in a known manner using one or more layers of PTFE sheets (abbreviation of polytetrafluoroethylene) or of adhesive paper.

Claims (6)

1. Transformateur d'intensité haute fréquence à air, caractérisé en ce qu'il comprend d'une part, un enroulement primaire (2) formé par une lamelle conductrice enroulée sur un mandrin isolant (1) comportant, une partie centrale rectangulaire (5) dont les grands côtés (5₁ , 5₂) s'étendent selon une première direction, et deux parties (6, 7) situées aux extrémités de la partie centrale (5) de forme à peu près rectangulaire dont les grands côtés (6₁ , 6₂ , 7₁ , 7₂) s'étendent selon une deuxième et une troisième direction de sens opposés l'une à l'autre, la longueur (L) de la partie centrale mesurée selon la première direction étant déterminée pour permettre aux deux extrémités (6, 7) d'avoir les directions de leurs grands côtés colinéaires deux à deux lorsque la partie centrale (5) considérée selon la première direction, est enroulée sur le mandrin (1), et en ce que les deux angles formés au croisement des bords (6₂ , 7₁) des parties situées aux extrémités avec les bords adjacents aux grands côtés (5₁ , 5₂) de la partie centrale, sont tronqués (8, 9) pour éviter le chevauchement des deux extrémités (6, 7) lorsque la partie centrale (5) est enroulée sur le mandrin (1) et d'autre part, un enroulement secondaire (4) à N spires jointives de fil émaillé enroulées au-dessus de la lamelle conductrice.1. High frequency air intensity transformer, characterized in that it comprises on the one hand, a primary winding (2) formed by a conductive strip wound on an insulating mandrel (1) comprising, a rectangular central part (5 ) whose long sides (5₁, 5₂) extend in a first direction, and two parts (6, 7) located at the ends of the central part (5) of roughly rectangular shape whose long sides (6₁, 6₂ , 7₁, 7₂) extend in a second and a third direction in opposite directions to each other, the length (L) of the central part measured in the first direction being determined to allow the two ends (6, 7) to have the directions of their long collinear sides two by two when the central part (5) considered in the first direction, is wound on the mandrel (1), and in that the two angles formed at the crossing of the edges ( 6₂, 7₁) of the parts situated at the ends with the edges adjacent to the gra nds sides (5₁, 5₂) of the central part, are truncated (8, 9) to avoid overlapping of the two ends (6, 7) when the central part (5) is wound on the mandrel (1) and other hand, a secondary winding (4) with N contiguous turns of enameled wire wound above the conductive strip. 2. Transformateur selon la revendication 1, caractérisé en ce que les deuxième et troisième directions forment un angle droit avec la première direction.2. Transformer according to claim 1, characterized in that the second and third directions form a right angle with the first direction. 3. Transformateur selon l'une quelconque des revendications 1 et 2, caractérisé en ce que le mandrin (1) est constitué par un tube en matière plastique.3. Transformer according to any one of claims 1 and 2, characterized in that the mandrel (1) consists of a plastic tube. 4. Transformateur selon l'une quelconque des revendications 1 à 3, caractérisé en ce qu'il comprend un écran (3) interposé entre l'enroule­ment primaire (2) et l'enroulement secondaire (4).4. Transformer according to any one of claims 1 to 3, characterized in that it comprises a screen (3) interposed between the primary winding (2) and the secondary winding (4). 5. Transformateur selon l'une quelconque des revendications 1 à 4, caractérisé en ce que l'enroulement secondaire (4) est formé par N spires jointives en fil émaillé.5. Transformer according to any one of claims 1 to 4, characterized in that the secondary winding (4) is formed by N contiguous turns in enameled wire. 6. Transformateur selon l'une quelconque des revendications 1 à 5, caractérisé en ce que la lamelle (2) est découpée dans une plaque de clinquant en cuivre.6. Transformer according to any one of claims 1 to 5, characterized in that the strip (2) is cut from a copper foil plate.
EP86402512A 1985-11-19 1986-11-12 Coreless-type high-frequency current transformer Expired - Lifetime EP0225241B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8517084 1985-11-19
FR8517084A FR2590400B1 (en) 1985-11-19 1985-11-19 HIGH FREQUENCY AIR INTENSITY TRANSFORMER

Publications (2)

Publication Number Publication Date
EP0225241A1 true EP0225241A1 (en) 1987-06-10
EP0225241B1 EP0225241B1 (en) 1991-07-17

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EP86402512A Expired - Lifetime EP0225241B1 (en) 1985-11-19 1986-11-12 Coreless-type high-frequency current transformer

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US (1) US4748430A (en)
EP (1) EP0225241B1 (en)
DE (1) DE3680299D1 (en)
FR (1) FR2590400B1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1762509B (en) * 2004-10-20 2010-05-26 合肥奥力智能系统有限公司 Acupoint electrostimulation device and method for improving cerebral function

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08330142A (en) * 1995-06-05 1996-12-13 Motorola Inc Surface installation electron component with grooved core and its preparation
US6160467A (en) * 1995-08-09 2000-12-12 Visteon Global Technologies, Inc. Transformer with center tap
US6660412B2 (en) * 2001-03-15 2003-12-09 Waseem A. Roshen Low loss, high frequency composite magnetic material and methods of making the same
FR2867916B1 (en) * 2004-03-17 2006-08-11 Lohr Ind HIGH VOLTAGE HIGH VOLTAGE ELECTRIC GENERATOR WITH LOW INTERNAL RESISTANCE AND HIGH ENERGY EFFICIENCY
US20090302986A1 (en) * 2008-06-10 2009-12-10 Bedea Tiberiu A Minimal-length windings for reduction of copper power losses in magnetic elements
US9287030B2 (en) * 2011-05-26 2016-03-15 Franc Zajc Multi gap inductor core
US10998124B2 (en) * 2016-05-06 2021-05-04 Vishay Dale Electronics, Llc Nested flat wound coils forming windings for transformers and inductors

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2860312A (en) * 1953-12-23 1958-11-11 Sarkes Tarzian Antenna input transformer
US3826967A (en) * 1973-05-29 1974-07-30 Pioneer Magnetics Inc Low leakage secondary circuit for a power transformer including conductive strips forming the secondary and connections for rectifying diodes
US4176335A (en) * 1977-10-25 1979-11-27 Burroughs Corporation Electrical conducting apparatus
US4236133A (en) * 1978-01-30 1980-11-25 Christian Rovsing A/S Transformer with foil windings

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2081979A (en) * 1934-08-28 1937-06-01 Rca Corp Ignition coil system
FR1133764A (en) * 1954-10-29 1957-04-02 Ferranti Ltd Windings improvements for transformers, reactors or other electromagnetic induction devices
AT237735B (en) * 1961-12-02 1965-01-11 Siemens Ag Process for the production of windings for transformers
US3312919A (en) * 1963-12-30 1967-04-04 Berkleonics Inc Shielded transformers
US3360754A (en) * 1965-06-29 1967-12-26 Wagner Electric Corp Transformer having reduced differential impedances between secondary portions

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2860312A (en) * 1953-12-23 1958-11-11 Sarkes Tarzian Antenna input transformer
US3826967A (en) * 1973-05-29 1974-07-30 Pioneer Magnetics Inc Low leakage secondary circuit for a power transformer including conductive strips forming the secondary and connections for rectifying diodes
US4176335A (en) * 1977-10-25 1979-11-27 Burroughs Corporation Electrical conducting apparatus
US4236133A (en) * 1978-01-30 1980-11-25 Christian Rovsing A/S Transformer with foil windings

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1762509B (en) * 2004-10-20 2010-05-26 合肥奥力智能系统有限公司 Acupoint electrostimulation device and method for improving cerebral function

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DE3680299D1 (en) 1991-08-22
FR2590400B1 (en) 1987-12-18
FR2590400A1 (en) 1987-05-22
US4748430A (en) 1988-05-31
EP0225241B1 (en) 1991-07-17

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