US3376531A - Electrical inductive apparatus with wire cloth shielding means - Google Patents

Electrical inductive apparatus with wire cloth shielding means Download PDF

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Publication number
US3376531A
US3376531A US575430A US57543066A US3376531A US 3376531 A US3376531 A US 3376531A US 575430 A US575430 A US 575430A US 57543066 A US57543066 A US 57543066A US 3376531 A US3376531 A US 3376531A
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United States
Prior art keywords
electrical
shielding means
wire cloth
conductive portion
corona
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Expired - Lifetime
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US575430A
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English (en)
Inventor
Heinz G Fischer
Clifford J Bell
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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Priority to US575430A priority Critical patent/US3376531A/en
Priority to CH1180167A priority patent/CH460159A/de
Priority to FR1551923D priority patent/FR1551923A/fr
Application granted granted Critical
Publication of US3376531A publication Critical patent/US3376531A/en
Anticipated expiration legal-status Critical
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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
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/324—Insulation between coil and core, between different winding sections, around the coil; Other insulation structures
    • 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
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/343—Preventing or reducing surge voltages; oscillations
    • 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
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36—Electric or magnetic shields or screens
    • 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
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36—Electric or magnetic shields or screens
    • H01F27/363—Electric or magnetic shields or screens made of electrically conductive material

Definitions

  • ABSTRACT 0F THE DISCLOSURE An electrical transformer having shielding means which includes an electrically conductive portion disposed between electrical insulating members.
  • the electrically conductive portion is formed of wire cloth having an electrical resistivity between .OZ and 2 ohms per square.
  • This invention relates in general to electrical inductive apparatus, such as transformers, and more particularly to new and improved shielding means for electrical inductive apparatus, such as static plates and corona shielding means.
  • shell-form transformers may utilize static plates disposed adjacent the line end pancake coils, and also on each side of any tapped coil sections, as well as corona shields disposed in the window opening of the pancake coils, between the window opening and -the portion of the magnetic core which is disposed therein.
  • Core-form transformers may utilize shielding means, at or cylindrical, depending upon the winding structure, to shield tapped coil sections and to enforce a favorable surge voltage distribution across the windings.
  • the shielding means i.e., corona shielding or enforcing favorable surge voltage distributions by establishing predetermined capacitive characteristics, or both, and regardless of whether the shielding means is connected to an elevated potential or to ground, the problems associated with these shielding means are essentially the same. lf the electrical resistance of the shielding means is too low, eddy current flow in the conductive portion of the shield becomes excessive in areas of high leakage flux, which increases the losses, as well as causing undesirable heating of the shielding means. If the resistance of the shielding means is too high, its usefulness is impaired.
  • the shielding means when used to distribute surge voltages by electrically charging the adjacent coils through capacitive relationships, the charging time -becomes too long, and surge potentials are not uniformly distributed.
  • the shielding means when using the shielding means as a corona shield, too high a resistance will not effectively reduce concentrations of electrical stress, and the shielding means will not remain at ground potential.
  • Shielding means for these applications were first made of copper foil. It is not possible to obtain copper foil thin enough, however, to increase the electrical resistance of the foil to the magnitude required to prevent excessive heating due to eddy currents.
  • the heating problems with copper foil led to shielding arrangement using an aluminum coating, sprayed on a sheet of insulating material, such as pressboard. While this arrangement is superior to arrangements utilizing copper foil, the resistance of the sprayed aluminum coating is still too flow, which results in overheating of the aluminum coating due to 12R loss, in areas of high leakage flux, where the direction of the leakage flux is perpendicular to the coating of aluminum.
  • shielding means which has the desired electrical resistance without resorting to masking, which is smooth enough to make it unnecessary to coat the conductive portion of the shield with epoxy, and then polish it, and which has a high mechanical strength and resistance to cracking.
  • shielding means which has the hereinbefore mentioned desirable characteristics, and which also allows electrical leads t0 be attached to the conductive portion of the shielding means before it is attached to the backup sheets of electrical insulation.
  • Another object of the invention is to provide new and improved shielding means for electrical inductive apparatus which has the desired electrical resistance, and whic hwill suppress eddy current losses and heating without resorting to the for-mation of predetermined patterns designed to breakup eddy current ow paths.
  • Still another object of the invention is to provide new and improved shielding means for electrical inductive apparatus which has an electrical resistance of sutiicient magnitude to minimize heating due to eddy currents, but low enough to function properly in its intended shielding application.
  • a further object of the invention is to provide new and improved shielding means for electrical inductive apparatus which has the desired electrical resistance, and a smooth surface which prevents electrical stresses from concentrating thereon.
  • Another object of the invention is to provide new and improved shielding means for electrical inductive apparatus which has a predetermined electrical resistance, high mechanical strength and resistance to cracking, and a construction which promotes rapid cooling.
  • Still another object of the invention is to provide new and improved shielding means for electrical inductive apparatus which has a predetermined desired resistance
  • Another object of the invention is to provide new and improved shielding means for electrical inductive .apparatus which has a predetermined desired electrical resistance, which has properties facilitating the formation of an excellent bond when glued between two sheets of electrical insulating means, and which will permit the penetration of the insulating and cooling dielectric of the electrical inductive apparatus, completely through the shielding means, including the conductive layer, to supplant all of the air in the shielding means.
  • the present invention accomplishes the above cited objects by forming the conductive portion of the shielding means of an electrically conductive wire cloth, mesh or screen.
  • Wire cloth constructed, for example, of 145 mesh stainless steel, provides an electrical resistance which minimizes eddy currents ⁇ without interfering with its intended shielding function, has a smooth surface which prevents corona discharges, has a large surfa-ce area which promotes fast cooling when exposed to high charging currents and/ or a high stray flux, has a high mechanical strength and resistance to cracking, facilitates the formation of excellent solder joints for making electrical connections thereto, allows electrical connections to be made thereto before attaching to solid insulation, facilitates excellent adhesion when sandwiched between electrical insulation and glued thereto, allows oil and other liquid dielectrics to freely pass through the electrically conductive portion to supplant all air trapped therein, and allows the finished shielding means to be bent or other- Wise mechanically stressed to iit its intended location, without danger of cracking the electrically conductive portion of the
  • the use of wire cloth as the electrically conductive portion of the shielding means substantially reduces manufacturing time and cost, as the time consuming and costly procedures of masking, coating with epoxy, and polishing, are completely eliminated.
  • FIGURE 1 is an elevational View, in section, partially cut away, of an electrical transformer illustrating a static plate and corona shielding means which may utilize the teachings of the invention
  • FIG. 2 is a cross-sectional view of a portion of the static plate shown in FIG. l, taken along the line II-II,
  • FIG. 3 is an exploded perspective View of the static plate shown in FIGS. 1 and 2,
  • FIG. 4 is a magnified view of the wire cloth which is used in constructing shielding means according to the teachings of the invention.
  • FIG. 5 is an enlarged, fragmentary cross-sectional view of the corona shielding means shown in FIG. 1.
  • FIG. 1 there is shown an elevational view, partially cut away, in section, of a transformer which may utilize the teachings of the invention.
  • Transformer 10 for purposes of example, is illustrated as being of the shell-form type, but any electrical inductive apparatus, such as transformers of the core-form type, electrical reactors, and like apparatus, may equally utilize the teachings of the invention.
  • Transformer 10 includes a core-coil assembly 12 disposed in a tank or casing 14, which is shown partially cut away.
  • Tank 14 may be filled to a predetermined level with a suitable insulating and cooling dielectric fluid, such as oil.
  • the core-coil assembly includes first and second magnetic core sections 16 and 18, respectively, each formed of a plurality of stacked metallic magnetic laminations 20, arranged to form at least one opening for receiving electrical coils, and with the magnetic core sections being disposed in side-by-side relation to form a common winding leg portion 22.
  • Transformer 10 may be single or poly-phase, and may be of the isolated winding, or autotransformer type.
  • the core-coil assembly 12 also includes a stack of pan-cake type coils all arranged on a common center line, and connected to form the high and low voltage windings.
  • Transformer 10 has been sectioned adjacent the high voltage winding, in order to illustrate static plate 24. Therefore, the pancake coils which make up the windings are not illustrated in FIG. l, but have the same general shape as static plate 2'4, and are all stacked in alignment, such that their openings for receiving the magnetic core are aligned, with the pancake coils being disopsed about winding leg 22.
  • Static plate 24 may be positioned at the end of the line end pancake coil of the high voltage winding and electrically connected to the pancake coil or to the high voltage terminal, in order to provide one plate of a capacitor, with the adjacent line end coil providing the other plate.
  • an electrical surge potential is applied to the high voltage terminal, such as caused by lightning or switching transients, the static plate quickly charges the line end coil and distributes the surge potential more uniformly across the line end coils.
  • Static plates are also used adjacent any tapped coil se-ctions, and may be used in many other arrangements, such as those taught in copending application Ser. No. 545,649, tiled Apr. 27, 1966, which is assigned to the same assignee as the present application.
  • corona shielding means 26 and 28 are electrically connected to ground, for example, to the magnetic core sections A16 and 18, in order to provide a smooth equipotential surface for shielding the sharp edges and corners of the magnetic core and prevent corona from forming.
  • Additional corona shielding means 30 and 32 may be disposed between the magnetic core sections and sides of the window openings in the pancake coils if necessary, to prevent corona at the sharp edges of the core laminations 20, in the event the laminations 20 are not accurately aligned.
  • support means may be included at the upper and lower spaces between t-he pancake coils and core leg 22.
  • metallic T- beams 34 and 36 may be provided, along with stacked magnetic laminations 38 and 40 for magnetically shielding the T-beam, and wedges 42 and 44 at the upper and lower spaces, respectively.
  • corona shielding means 26, 218, 30 and 32 must have an electrical resistivity high enough to minimize heating due to eddy currents, and low enough to remain Iat ground potential and effectively prevent concentrations of electrical stress about sharp corners and other points conductive to the buildup of electrical stress.
  • FIG. 2 is a cross-sectional view of static plate 24, taken along the line II-IL
  • stati-c plate 24 includes first and second sheettype insulating members 5t) 'and 52, formed, for example, of pressboard, which have the same general configuration as the pancake coils.
  • each sheet of insulating material has iirst and second major sides, each sheet is relatively thin, for example, .125 inch thick, and each has an opening sized to receive core leg 22 of magnetic core sections 16 and 18.
  • the conductive portion 54 of the static plate is disposed between the two insulating sheet members 50 and 52, and secured in position by gluing.
  • the conductive portion 54 is purposely sized to provide a small space 'between its edges and the inner and outer edges of the insulating sheet members, to insure that the conductive portion of the static plate is completely covered by electrical insulation.
  • electrically conductive wire structures 55 and 57 may be disposed in radially spaced relation about the inner and outer edges.
  • Wire structures 55 and 57 have a conductive strand 456 and 58, respectively, formed of copper, or other suitable electrical conductor, which are Wrapped with ⁇ suitable insulating means 60 and 62.
  • Conductive strands 56 and 58 are electrically connected to conductive portion 54 by electrical leads 64 and 66, respectively, and are held in position -by insulating channel members 68 and 70, -which may be formed of pressboard and glued to the insulating sheet members 50 and 52.
  • the electrically conductive portion S4 of the static plate 24 has presented many problems in the past, with many prior art constructions being very costly to manufacture and/or unreliable due to overheating.
  • Metallic foils of electrically conductive material are not commercially available which are thin enough to provide the desired electrical resistance, and the other necessary characteristics of the shielding means.
  • the resistance of the thinnest copper foil available is much too low, as eddy currents caused by leakage flux perpendicular to the major plane of the static plate provides a substantial 12R loss, resulting in overheating of the foil.
  • the sprayed aluminum conductive portion also requires th'at the ⁇ areas where electrical leads are to be soldered be sprayed Iwith copper, to facilitate a good solder connection.
  • Sprayed aluminum is relatively brittle, with cracks occurring when electrical leads are soldered thereto, or when lthe nal structure is bent or stressed during handling and installation.
  • Sprayed aluminum also, by its nature, is a mass of small particles which present a relatively rough surface, causing localized areas of high potential gradient with its resultant corona. Therefore, in the prior art, the sprayed aluminum is often -coated with a resinous insulating material, such as an epoxy resin, and tfhen the sprayed aluminum is polished. While this procedure provides an adequate structure, it will be apparent that the manufacture of the staticplate, using this process, is time consuming, costly and subject to a high percentage of rejects.
  • This invention solves these problems of the prior art, and p-rovides an excellent static plate, by constructing the electrically conductive portion S4 of a wire cloth, screen or mesh, having an electrical resistance between .02 and 2 ohms per square. Resistances in this range are available in wire cloth, such as those made of stainless steel, and the ⁇ wire cloth possesses all of the physical characteristics desirable in the construction of the static plate.
  • static plate 24 shown in FIGS. l and 2 is illustrated in an exvery well using a stainless steel flux, and conventional ploded perspective view in lFIG. 3, in which conductive portion 54 is separately shown.
  • FIG. 3 illustrates
  • Channel members 68 yand 70 are not shown in this view.
  • Electrically conductive portion 54 is formed of wire clot'h, screen, or mesh 80, shown in the magnied insert 82, which is formed of a plurality of woven metallic wires.
  • Wire cloth is avail-able which will provide the desired electrical resistivity, which solves the eddy current heating problem Iwithout resorting to the expedient of breaking up the eddy current paths by masking or stripping, and also possesses desirable physical characteristics.
  • Stainless steel 'wire cloth of 145 mesh which uses .0022 inch diameter wire, 250 mesh, which uses .0016 in-ch diameter Wire, and 325 mesh, which uses .0011 inch diameter wire, all provide excellent results.
  • the lower limit on mesh size is Iwhere the wire cloth no longer has a cloth-like appearance.
  • the mesh number refers to the number of openings per inch.
  • a mesh wire cloth l would have 100 openings per inch, in both directions, or 100 wires per inch in both directions, resulting in 10,000 openings in one square inch.
  • the commonly available cloth which has a different mesh number in two perpendicular directions would also be suitable.
  • wire cloth having 100 mesh in one direction and 40 mesh in the other would be suitable if its electrical resistance is in the ydesired range.
  • Conductive portion 54 shown in FIG. 3 may be very easily constructed. Since Wire cloth is available up to at least 48 inches wide, it is possible to form the electrically conductive portions for certain static plates in one piece, by cutting out opening 84 and Igap 76. If the static plate is wider than the available wire cloth, or if in the interest'of lowering the manufacturing cost it is desirable to minimize scrap, the electrically conductive portion 54 may be easily formed of a plurality of precut sections. . ⁇ I'oints, ⁇
  • Stainless steel wire cloth will solder lead-tin low temperature solder, by using a conventional soldering iron, The solder will only Wet'the stainless steel cloth where it has been fluxed, which permits strong accurate joints to be formed with a thin bead of solder.
  • the wire cloth also allows the connection of the various electrical conductors to be made to conductive portion 54 before it is associated with the insulating sheet members.
  • Electrical conductors such as electrical connectors 64 and 66 for connecting conductive portion 54 to wire structures 55 and 57, and electrical conductor 90 for connecting conductive portion 54 to an adjacent pancake coil or the high voltage terminal, may be made in any of several ways.
  • electrical conductors 64 and 66 are shown as thin strips of metallic foil, such as copper, which may be soldered to conductive portion 54.
  • Electrical conductor 90 may be formed by irst soldering a piece of copper foil 92 to conductive portion 54, and then spot welding a cable 94 to the copper foil 92.
  • Cable 94 may be constructed of a type of cable having a plurality of twisted strands. These Strands may be untwisted and iiared at one end, and then spot welded to the copper foil, or the flared strands may be soldered directly to conductive portion S4.
  • the plurality of openings in the cloth enable excellent solder joints to be obtained, as lthe solder enters the openings and forms a very high strength joint.
  • solder bead 96 may be formed to any desired width.
  • a suitable adhesive is applied to the sheet insulating members 50 and 52, or to the electrically conductive portion 54, or both, and conductive portion 54 is sandwiched between insulating members 50 and 52 and the resulting structure is pressed until the adhesive has cured.
  • a suitable adhesive which may be used is the casein type glue, 'which will allow the static plate structure 24 to be completely impregnated by the insulating and cooling dielectric iiuid in the transformer, insuring that any air trapped therein will be supplanted by the iiuid.
  • wire structures 55 and 57 are disposed about the inner and outer ed-ges of the structure, tacked in position by glass tape or other suitable means, and then insulating channel members 68 and 70, shown in FIG. 2, may be applied and glued in the position shown in FIG. 2.
  • Electrical connectors 64 and 66 may be wrapped about the electrically conductive strand portion of wire structures S and 57, which then completes static plate 24.
  • the use of wire cloth permits the conductive portion of the shielding means to be completely prepared as a subassembly, While it is separate from the insulating support and protective members, including the addition of the necessary electrical leads or connectors. This precludes the possible burning of the insulation members when the electrical leads are attached.
  • the wire cloth has a very high strength for its weight and is not brittle or subject to cracking or tearing. It is very iiexible, due t9 the small diameter wires used in the manufacture of the cloth, which permits the structure to be bent during handling and installation without danger of cracking the electrically conductive portion.
  • any heating produced in the static plate is quickly dissipated, as the surface area of the wire cloth is substantially greater than the surface area of metallic foil or a metallic coating.
  • the very line openings in the wire cloth facilitate solder connections, facilitate gluing the wire cloth to the backup insulating members, and promote complete impregnation of the shielding structure by the tiuid dielectric when disposed relative-to the electrical indue-tive apparatus.
  • the use of the teachings of the invention is not limited to static plates.
  • the corona shielding structures 26, 28, 30 and 32 shown in FG. 1 have substantially the same manufacturing problems as static plate 24, and the use of Vthe teachings of the invention provides additional benefits in the manufacture of curved or specially shaped shielding means, such as the curved shielding means 26 and 28.
  • FIG. 5 is a fragmentary cross-sectional view of corona shielding means 26 and 28 shown in FIG. l.
  • the curved corona shielding member 26 when using sprayed aluminum, has to be formed of pre-curved insulating members 102 and 104.
  • the sprayed aluminum coating is then applied to one of the members and the two insulating members 102 and v1li-tf are then glued together. Because of manufacturing tolerances, it is diflicult to obtain a perfect fit between the two curved members, which results in a high number of rejects and time consuming, costly manufacturing procedures.
  • corona shielding means 26 After corona shielding means 26 is formed, it is further bent or otherwise stressed while assembling it relative to the core winding leg and plurality of pancake coils, which may crack the metallic coating.
  • the electrically conductive coating 106 may be formed .of metallic wire cloth having the desired electrical resistivity.
  • Corona shielding member 26 may then .be formed in the same manner as hereinbefore described relative to static plate 24, by cutting the wire cloth 106 to shape, rounding the cut edges with a solder bead, and attaching electrical lead I108.
  • the wire cloth 106 may then be glued between insulating members 4102 and 104 while these insulating members are in the form of flat sheets. After the adhesive has cured, the resulting structure may be curved to the desired configuration without danger of cracking the wire cloth.
  • the corona shielding structure 26 may also be stressed and bent While assembling it in position in the inductive apparatus, without cracking the wire cloth.
  • Corona shielding member 30, which has electrical lead 110 attached thereto, is a substantially flat structure having two insulating sheet members 112 and 11d, which contain a wire cloth conductive portion 116 constructed as hereinbefore described relative to static plate 24.
  • An electrical transformer comprising a plurality of pancake coils having openings therein for receiving a magnetic core, said plurality of pancake coils being electrically connected to provide high and low voltage windings, and being stacked in sideJby-side relation with their openings in alignment, magnetic core means having a windin-g leg disposed through the aligned opening provided by said pancake coils, at least one static plate disposed adjacent a predetermined pancake coil and electrically connected thereto, said static plate having an electrically conductive portion disposed between two insulating sheet members, said electrically conductive poltion being formed of metallic wire cloth having an electrical resistance between .02 and 2 ohms per square, a tank, said plurality of pancake coils, said magnetic core means, and said at least one static plate being disposed within said tank, and fluid insulating and cooling means disposed to a predetermined level in said tank.
  • An electrical transformer comprising a plurality of pancake coils having openings therein for receiving a magnetic core, said plurality of pancake coils being electrically connected to provide high and low voltage windings, and Ibeing stacked in side-by-side relation with their openings in alignment, magnetic core means having a winding leg disposed through the aligned opening provided by said pancake coils, 'corona shielding means disposed between said magnetic core means and said plurality of pancake coils in the aligned opening provided by said plurality of pancake coils, said corona shielding means having an electrically conductive portion connected to ground, said electrically conductive portion being disposed between two insulating members, said electrically conductive portion being formed of metallic wire cloth having an electrical resistance between .02 and 2 ohms per square.
  • solder means said solder means being in the form of a solder bead disposed about the edges of said metallic wire cloth.
  • solder means said solder means being in the form of a solder bead disposed about the edges of said metallic wire cloth.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
US575430A 1966-08-26 1966-08-26 Electrical inductive apparatus with wire cloth shielding means Expired - Lifetime US3376531A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US575430A US3376531A (en) 1966-08-26 1966-08-26 Electrical inductive apparatus with wire cloth shielding means
CH1180167A CH460159A (de) 1966-08-26 1967-08-22 Elektrostatische Abschirmvorrichtung für elektrische Induktionsapparate, insbesondere Transformatoren
FR1551923D FR1551923A (de) 1966-08-26 1967-08-25

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CH (1) CH460159A (de)
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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3643196A (en) * 1970-07-10 1972-02-15 Westinghouse Electric Corp Electrical inductive apparatus
US3656077A (en) * 1969-09-08 1972-04-11 Alsthom Savoisienne Distribution of equipotential surfaces of inductance windings comprising layers with a double series of steps
US3699488A (en) * 1972-02-28 1972-10-17 Allis Chalmers Distribution transformer having static shield
US4227037A (en) * 1979-05-29 1980-10-07 Gulf & Western Manufacturing Company Shielded non-metallic container
US4639282A (en) * 1985-02-19 1987-01-27 Asea Aktiebolag Insulation of metallic surfaces in power transformers
US4977301A (en) * 1988-10-13 1990-12-11 Matsushita Electric Industrial Co., Ltd. High-frequency heating apparatus using frequency-converter-type power supply
US5066937A (en) * 1990-06-24 1991-11-19 Barkley & Dexter Laboratories Search coil assembly with laminate frame members and method for making same
US7477120B2 (en) * 2001-08-13 2009-01-13 Bose Corporation Transformer shielding
JP2010092915A (ja) * 2008-10-03 2010-04-22 Mitsubishi Electric Corp 静電板
EP2797091A1 (de) * 2013-04-25 2014-10-29 Nxp B.V. Transformator und Stromversorgung mit Transformator
US20170358390A1 (en) * 2016-06-10 2017-12-14 Abb Schweiz Ag Cooling arrangement

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US1370093A (en) * 1919-03-10 1921-03-01 Sperry Gyroscope Co Ltd Receiving-panel
US1872293A (en) * 1931-06-05 1932-08-16 Westinghouse Electric & Mfg Co Transformer
US1962584A (en) * 1929-01-08 1934-06-12 Davies Drury Norman Sheet of coated metal for earthed panels and other purposes
US2405987A (en) * 1941-11-18 1946-08-20 Orlan M Arnold High-frequency shielding
US2755079A (en) * 1952-02-29 1956-07-17 Otto H York Elastic metal mesh tubular bellows
US2793245A (en) * 1953-01-21 1957-05-21 Ace Engineering & Machine Co I Radio shielded enclosures
US2958754A (en) * 1958-12-15 1960-11-01 Gen Electric Electronic ovens
US2993183A (en) * 1957-10-30 1961-07-18 Westinghouse Electric Corp Transformer structures
US3030435A (en) * 1959-06-02 1962-04-17 American Cyanamid Co Shielding panel with wire embedment
US3183462A (en) * 1963-04-10 1965-05-11 Westinghouse Electric Corp Shielding means for electrical apparatus
US3305623A (en) * 1964-10-19 1967-02-21 Metex Corp Shielded window construction

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1370093A (en) * 1919-03-10 1921-03-01 Sperry Gyroscope Co Ltd Receiving-panel
US1962584A (en) * 1929-01-08 1934-06-12 Davies Drury Norman Sheet of coated metal for earthed panels and other purposes
US1872293A (en) * 1931-06-05 1932-08-16 Westinghouse Electric & Mfg Co Transformer
US2405987A (en) * 1941-11-18 1946-08-20 Orlan M Arnold High-frequency shielding
US2755079A (en) * 1952-02-29 1956-07-17 Otto H York Elastic metal mesh tubular bellows
US2793245A (en) * 1953-01-21 1957-05-21 Ace Engineering & Machine Co I Radio shielded enclosures
US2993183A (en) * 1957-10-30 1961-07-18 Westinghouse Electric Corp Transformer structures
US2958754A (en) * 1958-12-15 1960-11-01 Gen Electric Electronic ovens
US3030435A (en) * 1959-06-02 1962-04-17 American Cyanamid Co Shielding panel with wire embedment
US3183462A (en) * 1963-04-10 1965-05-11 Westinghouse Electric Corp Shielding means for electrical apparatus
US3305623A (en) * 1964-10-19 1967-02-21 Metex Corp Shielded window construction

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3656077A (en) * 1969-09-08 1972-04-11 Alsthom Savoisienne Distribution of equipotential surfaces of inductance windings comprising layers with a double series of steps
US3643196A (en) * 1970-07-10 1972-02-15 Westinghouse Electric Corp Electrical inductive apparatus
US3699488A (en) * 1972-02-28 1972-10-17 Allis Chalmers Distribution transformer having static shield
US4227037A (en) * 1979-05-29 1980-10-07 Gulf & Western Manufacturing Company Shielded non-metallic container
US4639282A (en) * 1985-02-19 1987-01-27 Asea Aktiebolag Insulation of metallic surfaces in power transformers
EP0364171A3 (de) * 1988-10-13 1991-05-08 Matsushita Electric Industrial Co., Ltd. Hochfrequenzheizgerät mit einer frequenzumwandelnden Speisung
US4977301A (en) * 1988-10-13 1990-12-11 Matsushita Electric Industrial Co., Ltd. High-frequency heating apparatus using frequency-converter-type power supply
US5066937A (en) * 1990-06-24 1991-11-19 Barkley & Dexter Laboratories Search coil assembly with laminate frame members and method for making same
US7477120B2 (en) * 2001-08-13 2009-01-13 Bose Corporation Transformer shielding
JP2010092915A (ja) * 2008-10-03 2010-04-22 Mitsubishi Electric Corp 静電板
EP2797091A1 (de) * 2013-04-25 2014-10-29 Nxp B.V. Transformator und Stromversorgung mit Transformator
US20170358390A1 (en) * 2016-06-10 2017-12-14 Abb Schweiz Ag Cooling arrangement
CN107492438A (zh) * 2016-06-10 2017-12-19 Abb瑞士股份公司 冷却装置
US10643777B2 (en) * 2016-06-10 2020-05-05 Abb Schweiz Ag Cooling arrangement
CN107492438B (zh) * 2016-06-10 2021-01-22 Abb电网瑞士股份公司 冷却装置和变压器

Also Published As

Publication number Publication date
CH460159A (de) 1968-07-31
FR1551923A (de) 1969-01-03

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