US3895334A - Electrical choke coil of the air core type - Google Patents

Electrical choke coil of the air core type Download PDF

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Publication number
US3895334A
US3895334A US340755A US34075573A US3895334A US 3895334 A US3895334 A US 3895334A US 340755 A US340755 A US 340755A US 34075573 A US34075573 A US 34075573A US 3895334 A US3895334 A US 3895334A
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US
United States
Prior art keywords
coil
conductor
electrical
layer
glass
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US340755A
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English (en)
Inventor
Manfred Baier
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.)
BBC Brown Boveri AG Switzerland
Original Assignee
Bbc Brown Boveri & Cie
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Application filed by Bbc Brown Boveri & Cie filed Critical Bbc Brown Boveri & Cie
Application granted granted Critical
Publication of US3895334A publication Critical patent/US3895334A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F37/00—Fixed inductances not covered by group H01F17/00
    • H01F37/005—Fixed inductances not covered by group H01F17/00 without magnetic core
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • H01F41/12—Insulating of windings
    • H01F41/122—Insulating between turns or between winding layers
    • 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
    • H01F27/327—Encapsulating or impregnating
    • H01F2027/328—Dry-type transformer with encapsulated foil winding, e.g. windings coaxially arranged on core legs with spacers for cooling and with three phases

Definitions

  • ABSTRACT An electrical choke coil of the air-core type formed by a helically wound insulated electrical conductor.
  • the coil turns are substantially contiguous and are adhered to each other so as to bond all of the coil turns into an integral whole.
  • the adhering agent is an epoxy-resin of the free air-curable type with which the insulation on the conductor is impregnated, and the conductor insulation includes a first layer of glass-mica tape and a second layer of glass-fibre tape.
  • Spider type supports are located at each end of the coil and these are held against the coil ends by tensioned straps of insulating material extending between the supports.
  • a tape of insulating material is wound onto the exterior surface of the coil to form a binding layer which further protects the coil against radial expansion.
  • This invention relates to an improvement in the construction of electrical choke coils of the helically wound air-core type and also to a novel method and apparatus by which the coil is made.
  • Electrical choke coils ofthe air-core type have many uses in the electrical field. They are used as line traps in carrier communications. as current-limiting reactors and as smoothing chokes. Since in the case of a shortcircuit, the total short cireuit current flows through the coils. the coils must be dimensioned and constructed in such manner as to enable them to withstand the very high mechanical and thermal stresses which arise therein during short-circuit conditions. Flow of high order currents through the coil result in the creation of mechanical forces in the cylindrically configured coil which tend to expand the coil diameter in the same manner as results from an increase in internal pressure within a tube. Hence, means are required to bind and restrain the coil turns from expanding in a radially outward direction.
  • the magnetic field produced by the high order short-circuit current results also in the creation of a compressive force on the coil turns which acts in an axial direction.
  • the choke coils are constructed such that spacer members are located between adjacent turns of the coil to provide for circulation of cooling air between them. This axially directed compressive force may lead to bending of the conductor parts located between the spacer members.
  • a common construction arrangement is to locate the helical coil between two insulating cylinders.
  • This arrangemcnt has. however. the disadvantage that for different coil diameters and different conductor dimensions.
  • insulating cylinders of varied dimensions are required which, in fact. is quite complicated. Further more. due to the presence of a number of air-traps adjacent the conductor surface, the heat dissipation factor of such coils is very poor.
  • the principal object of the present invention is to provide an improved construction for choke coils of the air core type which do not suffer from the disadvantages of past constructions, i.e. coils which will stand up under short-circuit current conditions and which will also provide better cooling.
  • the improved air-core choke coil structure is characterized by a helical winding of an insulated electrical conductor and wherein the individual turns of the coil which lie closely adjacent to each other are adhered together by an adhesive so as to bond the individual coil turns together into an integral whole capable of withstanding all forces to which it is subjected during operation.
  • the coil can be manufactured by first providing the bare conductor material with an insulating layer. then winding the conductor helically into the desired cylindrical form and then bonding the individual turns together.
  • the adhesive material e.g. an epoxy resin. can be impregnated into the insulating material before winding it onto the bare conductor. or the complete coil after winding can then be impregnated with the epoxy resin and then cured so as to harden it and complete the bonding operation.
  • Aldrey-alloy is advantageous.
  • For conductor insulation a two-layer construction is preferred. the first layer being a winding of glass mica tape for insulation and the second layer being a winding of glass tape for mechanical protection.
  • the choke coil having its insulated turns adhered together can also be provided with an outer binding of electrical insulating tape to further improve the resistance ofthe coil to radially outward expansion forces created by the short-circuit current.
  • spider type supports can be provided at each end of the choke coil, these spiders being drawn together under tensional force by means of one or more circumferentially distributed axially extending straps of insulating material, preferably made from glass fiber which are tensioned.
  • Apparatus for performing the method by which the improved choke coil structure is produced preferably includes a rotary cylindrical mandrel on which the conductor is wound helically to form the coil, a supply roll of the bare conductor and a conductor-taping station intermediate the conductor supply roll and the mandrel for winding on at least one layer of insulating tape to the conductor, the particular taping station to be illustrated including a first station for winding on a glassmica tape to the bare conductor for insulation and a second station thereafter winding on a glass-fibre tape for mechanical protection.
  • the tapes can be impregnated with an epoxy-resin or plain tape can be used. in which case an impregnating station is provided to receive the choke coils after they have been wound on the mandrel.
  • FIG. I is a top plan view of a choke coil designed to function as a line trap" and which is constructed in accordance with the invention
  • FIG. 2 is a view in longitudinal section through the coil taken on line lll
  • FIG. 2a is an enlarged section detail of a portion of the coil structure.
  • FIG. 3 is an enlarged view of a portion of the conduc tor structure and the insulating layers thereon;
  • FIG. 4 is a somewhat diagrammatic view in perspective of apparatus by which the choke coil can be made.
  • the line-trap choke coil is seen to be comprised of a closely wound helix of an electrical conductor 2 having insulation 1 applied thereto, the coil turns being essentially contiguous i,e. touching each other as shown in FlGS. 2 and 2a and being adhered together by means of an adhesive 14.
  • the conductor insulation consists of two superposed layers In and lb as shown in FIG. 3, the inner layer In being a winding of glassmica tape on the bare conductor for electrical insulation purposes and the other layer lb being a winding of glass-fibre tape which is utilized for mechanical protection.
  • the two layers of tape are wound on helically in opposite directions, one being wound on clockwise and the other counter-clockwise.
  • Adhesion of the contiguous turns of the coil can be effected by means of an adhesive, cg. an epoxy-resin, with which the insulating tapes la and lh are impregnated prior to winding on; alternatively, the adhesive 14 can be added after the coil is wound by impregnating the completed coil with the epoxy-resin by an immersion process, and then curing so as to harden the resin and transform the coil into a compact and rigid self supporting cylinder.
  • an adhesive cg. an epoxy-resin, with which the insulating tapes la and lh are impregnated prior to winding on
  • the adhesive 14 can be added after the coil is wound by impregnating the completed coil with the epoxy-resin by an immersion process, and then curing so as to harden the resin and transform the coil into a compact and rigid self supporting cylinder.
  • Aldrey aluminum alloy is preferred. This is an alloy consisting of approximately 0.5 to 0.6 Si, approximately 0.4 to 0.5 Mg, the remainder being A].
  • concentrically arranged coils each constructed as above described, can be used, the coils being connected in parallel. In such case, in order to obtain an equal distribution of current. the number of turns of the outer coil should be less than that of the inner coil.
  • an outer wrapping of an electrically insulating tape 3 can be applied to the surface of the coil as depicted in FIG. 2 and which thus performs a binding function.
  • spider type support structures 4 and S are applied to opposite ends of the coil and these are held against their corresponding ends of the coil by means of straps 6, one for each leg of the spider, made from glass-fibre and which are stressed in tension.
  • Apparatus constructed in accordance with the details depicted in FIG. 4 for forming the choke coil include a cylindrical mandrel 7 which is mounted for rotation about its axis by drive means, not shown, the insulated conductor being would helically on the mandrel as the latter is rotated, a supply spool 8 for the bare conductor 2, and conductortaping station located intermediate the supply spool 8 and mandrel 7 which includes a first LII taping station 9 wherein a first layer In of glass-mica tape is wound helically onto the bare conductor in a counterclockwise direction and a second taping station 10 where a second layer lb of glass-fibre is wound helically onto the first layer la,
  • the driving mechanism for thc mandrel 7 and tape winders at stations 9 and 10 are properly synchronized so that successive turns of the tape layers la and lb will have the desired amount of overlap as the conductor is fed through the taping stations.
  • the epoxy-resin can be selected from the known group of such compositions which are curable in the open air and can be pigmented with a coloring agent, if desired, to increase their thermal-radiation characteristic,
  • An electrical choke coil of the air-core type comprising a helically wound insulated electrical conductor, the insulation on said conductor comprising an inner layer of glass-mica material applied to the conductor and an outer layer of glassfibre material, the in dividual turns of said helical coil being in touch with each other and bonded together into an integral whole by application of an electrically insulating adhering agent thereto, a binding layer of electrical insulating tape applied only to the outer surface of said coil for reinforcing the coil structure against radial expansion when subjected to currents of short-circuit magnitude, support spiders engaging each end of said coil, and tensioning straps of electrical insulating material extending between said support spiders inside of said coil for holding said support spiders against the coil ends under tension.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Insulating Of Coils (AREA)
  • Coil Winding Methods And Apparatuses (AREA)
  • Coils Of Transformers For General Uses (AREA)
  • Insulation, Fastening Of Motor, Generator Windings (AREA)
US340755A 1972-03-17 1973-03-13 Electrical choke coil of the air core type Expired - Lifetime US3895334A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH401072A CH543165A (de) 1972-03-17 1972-03-17 Verfahren zur Herstellung einer ein- oder mehrlagigen Luftdrosselspule, gemäss diesem Verfahren hergestellte Luftdrosselspule, Vorrichtung zur Durchführung des Verfahrens und Anwendung des Verfahrens

Publications (1)

Publication Number Publication Date
US3895334A true US3895334A (en) 1975-07-15

Family

ID=4268113

Family Applications (1)

Application Number Title Priority Date Filing Date
US340755A Expired - Lifetime US3895334A (en) 1972-03-17 1973-03-13 Electrical choke coil of the air core type

Country Status (9)

Country Link
US (1) US3895334A (enExample)
JP (1) JPS5321102B2 (enExample)
AT (1) AT323838B (enExample)
CA (1) CA1007723A (enExample)
CH (1) CH543165A (enExample)
DE (1) DE2218018A1 (enExample)
FR (1) FR2176740B3 (enExample)
GB (1) GB1411513A (enExample)
IT (1) IT998094B (enExample)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3305007A1 (de) 1983-01-27 1984-08-09 BBC Aktiengesellschaft Brown, Boveri & Cie., Baden, Aargau Luftdrosselspule und verfahren zu ihrer herstellung

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1170321A (en) * 1982-01-20 1984-07-03 Richard F. Dudley Low loss spider support for coil of an inductive apparatus

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1270831A (en) * 1913-07-29 1918-07-02 Westinghouse Electric & Mfg Co Static protective apparatus.
US1739246A (en) * 1926-11-10 1929-12-10 Majce Johann Method of manufacturing wire coils
US2234560A (en) * 1938-11-16 1941-03-11 Westinghouse Electric & Mfg Co Covered wire
US2795640A (en) * 1956-02-01 1957-06-11 Gen Electric Electrical cable subject to irradiation
US2829191A (en) * 1954-04-07 1958-04-01 Westinghouse Electric Corp Polymerizable polyester and vinylidene monomer resinous composition and electrical conductor insulated therewith
US2856547A (en) * 1955-10-24 1958-10-14 Anaconda Wire & Cable Co Insulation of electrical devices
US3135888A (en) * 1961-02-01 1964-06-02 Gen Electric Structure for retaining generator end windings
US3237136A (en) * 1964-11-19 1966-02-22 Westinghouse Electric Corp Coils for inductive apparatus
US3493531A (en) * 1964-10-23 1970-02-03 Westinghouse Electric Corp Rigid crack resistant resinous casting composition
US3676814A (en) * 1970-02-06 1972-07-11 Westinghouse Electric Corp High temperature adhesive overcoat for magnet wire
US3696315A (en) * 1970-09-24 1972-10-03 Westinghouse Electric Corp Line traps for power line carrier current systems

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1270831A (en) * 1913-07-29 1918-07-02 Westinghouse Electric & Mfg Co Static protective apparatus.
US1739246A (en) * 1926-11-10 1929-12-10 Majce Johann Method of manufacturing wire coils
US2234560A (en) * 1938-11-16 1941-03-11 Westinghouse Electric & Mfg Co Covered wire
US2829191A (en) * 1954-04-07 1958-04-01 Westinghouse Electric Corp Polymerizable polyester and vinylidene monomer resinous composition and electrical conductor insulated therewith
US2856547A (en) * 1955-10-24 1958-10-14 Anaconda Wire & Cable Co Insulation of electrical devices
US2795640A (en) * 1956-02-01 1957-06-11 Gen Electric Electrical cable subject to irradiation
US3135888A (en) * 1961-02-01 1964-06-02 Gen Electric Structure for retaining generator end windings
US3493531A (en) * 1964-10-23 1970-02-03 Westinghouse Electric Corp Rigid crack resistant resinous casting composition
US3237136A (en) * 1964-11-19 1966-02-22 Westinghouse Electric Corp Coils for inductive apparatus
US3676814A (en) * 1970-02-06 1972-07-11 Westinghouse Electric Corp High temperature adhesive overcoat for magnet wire
US3696315A (en) * 1970-09-24 1972-10-03 Westinghouse Electric Corp Line traps for power line carrier current systems

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3305007A1 (de) 1983-01-27 1984-08-09 BBC Aktiengesellschaft Brown, Boveri & Cie., Baden, Aargau Luftdrosselspule und verfahren zu ihrer herstellung
US4538131A (en) * 1983-01-27 1985-08-27 Bbc Brown, Boveri & Company, Ltd. Air-core choke coil

Also Published As

Publication number Publication date
JPS4919344A (enExample) 1974-02-20
FR2176740A1 (enExample) 1973-11-02
CH543165A (de) 1973-10-15
AT323838B (de) 1975-07-25
CA1007723A (en) 1977-03-29
GB1411513A (en) 1975-10-29
IT998094B (it) 1976-01-20
DE2218018A1 (de) 1973-09-27
JPS5321102B2 (enExample) 1978-06-30
FR2176740B3 (enExample) 1976-03-12

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