US3313879A - Treated cellulosic material and electrical apparatus embodying the same - Google Patents

Treated cellulosic material and electrical apparatus embodying the same Download PDF

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Publication number
US3313879A
US3313879A US319387A US31938763A US3313879A US 3313879 A US3313879 A US 3313879A US 319387 A US319387 A US 319387A US 31938763 A US31938763 A US 31938763A US 3313879 A US3313879 A US 3313879A
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United States
Prior art keywords
cellulosic
insulation
paper
electrical
electrical apparatus
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Expired - Lifetime
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US319387A
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English (en)
Inventor
James G Ford
Anthony J Palumbo
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CBS Corp
Original Assignee
Westinghouse Electric Corp
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 Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US319387A priority Critical patent/US3313879A/en
Priority to GB40212/64A priority patent/GB1083557A/en
Priority to GB42143/66A priority patent/GB1094884A/en
Priority to ES0304909A priority patent/ES304909A1/es
Priority to NO161237A priority patent/NO115591B/no
Priority to FR993064A priority patent/FR1413432A/fr
Application granted granted Critical
Publication of US3313879A publication Critical patent/US3313879A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06MTREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M13/00Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
    • D06M13/322Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing nitrogen
    • D06M13/402Amides imides, sulfamic acids
    • D06M13/415Amides of aromatic carboxylic acids; Acylated aromatic amines
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/03Non-macromolecular organic compounds
    • D21H17/05Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
    • D21H17/07Nitrogen-containing compounds
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/03Non-macromolecular organic compounds
    • D21H17/05Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
    • D21H17/07Nitrogen-containing compounds
    • D21H17/08Isocyanates
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/185Substances or derivates of cellulose
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00Insulated conductors or cables characterised by their form
    • H01B7/02Disposition of insulation
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/28Coils; Windings; Conductive connections
    • H01F27/32Insulating of coils, windings, or parts thereof
    • H01F27/323Insulation between winding turns, between winding layers

Definitions

  • cellulosic-materials such as paper, cottoncloth, cot; ton tape, pressboard and wood have long been employed for many purposes.
  • One use has been in the electrical industry as-insulation for various types of electricalapparatus.
  • Such materials represent a desirable source of electrical insulation from the standpoint of their economic advantages over other available types of insulation.
  • cellulosic insulation possesses good physical properties, generally speaking, and satisfactory initial dielectric strength.
  • terial such as paper, cotton cloth, cotton type, pressbbard and wood deteriorate at an increasing rate when the temperature is increased above 100C. whether exposed to air or in contact with fluid'dielectric compositions.
  • paper after being immersed for only a few weeks in refined petroleum transformer oil at 120 to 150 C. paper will retain practically none of its original tensile strength.
  • a length of fresh electrical grade lira-ft paper may be bent or flexed several hundred times before it will break.
  • it will break upon being double folded once.
  • a primary object of the invention is to provide a stabilized cellulosic electrical insulation'char acterized by both improved thermal stability and improved dielectric integrity.
  • a further object of the invention is the provision of improved cellulosic electrical insulation containing effecave amounts of certain nitrogen-containing chemical stabilizing compounds.
  • FIG. 1 is a view in perspective, partly .in cross section, of a transformer core insulated with the novel cellulosic insulation of the invention
  • FIG. 2 is a view in elevation, partly in cross section, of a transformer
  • FIG. 3 is a view in elevation, partly in cross section, illustrating an insulated cable.
  • the chemical stabilization compounds must be present in the cellulosic insulation in amounts within the range of about 0.02% to about 10% by weight based on the weight of the cellulosic material.
  • these compounds are substantially oil insoluble thus preventing depletion of the uniform distribution of the stabilization compound in the cellulosic insulation in the presence of oil type dielectrics.
  • 1-napthylisocyanate it may be incorporated into the cellulosic insulation by the use of ether or some other suitable non-active hydrogen bearing solvent.
  • the stabilizing compounds be closely associated at all times with the cellulose fibers to obtain the hereinbefore discussed benefits particularly where the insulation is to be immersed in a liquid dielectric such as oil during use.
  • the stabilizing materials are merely suspended in a liquid dielectric, an extended period of time elapses before the stabilizers permeate the cellulosic insulation and function at substantial effectiveness.
  • paper is generally made on either a Fourdrinier machine or a cylinder type machine. In either method the formed web of felted cellulosic fibers is transferred from the forming screen to a felt belt for drying. The web is thereby carried through a drier which consists of a number of steam heated rolls after which, if desired, it is passed between calender rolls to impart a particular surface finish ordensity and finally it is rolled for storage and shipment. Also, generally, the drier is split so that the paper Web is partially dried in the first portion thereof and is finish dried in the second portion. Between these two drying sections of heated rolls a tank is positioned for application of sizing materials to the paper.
  • a tank is positioned for application of sizing materials to the paper.
  • the stabilizing compounds in substantially aqueous solution, are present in the conventional
  • the partially dried means of appropriate adjustments in the concentration of the solution, the paper absorbs a predetermined amount of stabilizing compounds.
  • solution temperatures of about 60 to 90 C. are adequate to produce a suitably concentrated solution.
  • the paper passed through the second portion of the drier. The temperature of the rolls is determined by trial so as to obtain sufficient paper drying and avoid sticking to the calender rolls. The process is applicable equally to either the Fourdrinier or cylinder type paper-making machine.
  • the dried paper contains the stabilizing compounds uniformly distributed throughout its interstices.
  • Table I lists mechanical strength retention of treated paper for the stabilization compounds of the invention together with the mechanical strength retention for untreated kraft paper for comparision purposes.
  • 3% by weight of the particular stabilizing compound was added to kraft paper during its manufacture.
  • the paper was about 5 mils
  • Each of the samples of paper was wound with enameled wire into a coil and sealed in a tank filled with transformer oil. Strips of transformer core iron were also placed in the tank. Sufficient current was circulated through the coil to generate temperatures of 140 C. The coil unit was removed after seven days and a Mullens bursting strength test run on the aged paper.
  • Table I lists the percent strength retention of the aged samples as compared to the pre-aging Mullens bursting strength. There is some direct relation between mechanical strength retention and dielectric properties retention for the cellulosic materials of the invention in that where treated cellulosic material exhibits a high retention of mechanical strength, such as the paper indicated in Table I, it also exhibits corresponding high retention of dielectric integrity.
  • a transformer is wound in a manner as illustrated in FIG. 1 using paper treated in accordance with the invention containing 3% by weight of one or more of the stabilizing compounds disclosed in the invention.
  • the numeral 10 represents the treated kraft paper which is wound around the individual coils and which is wound between the high and low voltage coils of the transformer.
  • transformer coil comprises low voltage'coils 14 and 16, as well as high voltage coils 18, 20 and 22, insulated by layer-to-layer application of the treated paper.
  • the low voltage coil 14 is insulated from the treated winding-to-Winding by insulation 24.
  • the electrical conductors employed may comprise enameled wire which resists softening at temperatures of up to 250? C. Suitable enamels are epoxy resin enamels, polyester resin enamels such as isophthalate-glycol-maleate resins, sili-.
  • cone modified enamels and polyvinyl formal-phenolic resin enamels may be applied directly on top of wire or may be employed with asbestos or glass fiber wrapping or other fibrous materials.
  • a liquid dielectric such as oil, or a chlorinated aromatic dielectric, will fill the channels 26 and will, as well, completely permeate the paper insulation. Subsequent to being wound and assembled the entire assembly is vacuum treated to remove air and moisture from the paper and the coil is thereafter baked to.
  • a transformer is prepared in accordance with the present invention.
  • the transformer comprises a tank 28 carrying a'support 30 in-.
  • Coil 34 comprises a high voltage winding 36 and a low voltage winding 38, each insulated with a wire enamel composition which resists softening at temperatures up to 250 C.
  • the turns of the. windings 36 and 38 are insulated by wrappings comprising the stabilized.
  • tion which comprises paper, cotton or other cellulosic insulation.
  • An exterior cellulosic wrapping 42 of cloth or paper may be applied to the coil 34.
  • pressboard, wood or cardboard spacers or various other cellulosic products may be applied to the electrical windings.
  • a liquid dielectric 44 is disposed within the tank 28 to cover the core 32 and coil 34 in order to insulate them and to dissipate the heat produced in operating the transformer.
  • the treated cellulose materials of this invention retain their dielectric properties and mechanical strength when in contact with a liquid dielectric containing a small amount of an oxidation inhibitor, such as para-tert butyl phenol.
  • FIGURE 3 illustrates an electrical conducting cable comprising an electrical conductor 50 having cellulosic insulation 52 Wrapped thereabout and an outer metallic sheath covering 54.
  • the cellulosic insulation 52 is stabilized material which has been treated according to the present invention.
  • transformer construction may be more solid and tight because the treated cellulosic spacers and other components Will lose less than half the thickness loss on thermal aging exhibited by untreated pressboard, kraft paper or other cellulosic materials.
  • cellulosic insulation stabilizing compounds of the invention may be used singly or in combination With one another, or further, in combination with these or the stabilizing compounds disclosed in copending patent applications Ser. No. 164,113, filed Jan. 3, 1962 and Ser. No. 839,166, filed Sept. 10, 1959 and its continuation-in-part Patent 3,102,159 issued Aug. 27, 1963, or application Ser. No. 319,174, filed concurrently herewith.
  • An improved sheet cellulosic product having increased stability and resistance to thermal deterioration and particularly adapted for use in electrical apparatus in combination with a fluid dielectric impregnant in contact with the cellulosic product, the cellulosic product comprising cellulosic fibers in sheet form, the sheet having uniformly distributed therethrough from about 0.02%
  • At least one stabilizing compound selected vfrom the group consisting of l-naphthylisocyanate, acetanilide, p-aminoacetanilide, benzamide, carbanilide, dimethylacetamide, malonamide, N,N-methylene-bis-acrylamide, N-t-butylacrylamide, N-methylolacrylamide, N-toctylacrylamide, l-cyanoacetamide, and benzanilide.
  • the improved sheet cellulosic product of claim 1 having increased stability and resistance to thermal deterioration and particularly adapted for use in electrical apparatus in combination with a fluid dielectric impregnant in contact with the cellulosic product wherein the sheet has uniformly distributed therethrough from about .5 to about 5% by weight, based on the weight of the cellulosic fibers, of at least one stabilizing compound selected from the group consisting of l-naphthylisocyanate, acetanilide, p-aminoacetanilide, benzamide, carbanilide, dimethylacetamide, malonamide, N,N-methylene-bis-acrylamide, N-t-butylacrylamide, N-methylolacrylamide, N-t-octylacrylamide, l-cyanoacetamide, and benzanilide.
  • an electrical apparatus comprising in combination a container and disposed therein an electrical conductor winding provided with a hard, tough flexible enamel coating which resists softening at temperatures up to about 250 C. and cellulosic electrical insulation substantially disposed around the winding, the improvement which comprises providing from about 0.02% to 10% by Weight, based on the Weight of the cellulosic electrical insulation of a stabilizing compound, the stabilizing compound being uniformly distributed throughout the cellulosic electrical insulation, and a liquid dielectric consisting essentially of a petroleum hydrocarbon oil in the said container surrounding at least part of said electrical conductor Winding and substantially completely permeating said cellulosic electrical insulation, the said stabilizing compound serving to improve the resistance of the cellulosic insulation to thermal deterioration when heated in the presence of the said liquid dielectric, the said stabilizing compound comprising at least one compound selected from the group consisting of l-naphthylisocyanate, acetanilide, p-aminoacetanilide, benzamide

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Textile Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Paper (AREA)
  • Organic Insulating Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Insulating Of Coils (AREA)
US319387A 1963-10-28 1963-10-28 Treated cellulosic material and electrical apparatus embodying the same Expired - Lifetime US3313879A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US319387A US3313879A (en) 1963-10-28 1963-10-28 Treated cellulosic material and electrical apparatus embodying the same
GB40212/64A GB1083557A (en) 1963-10-28 1964-10-02 Treated cellulosic material and electrical apparatus embodying same
GB42143/66A GB1094884A (en) 1963-10-28 1964-10-02 Treated cellulosic material and electrical apparatus embodying the same
ES0304909A ES304909A1 (es) 1963-10-28 1964-10-14 Mejoras introducidas en la fabricacion de materiales celulosicos en hojas.
NO161237A NO115591B (no) 1963-10-28 1964-10-20
FR993064A FR1413432A (fr) 1963-10-28 1964-10-28 Matière cellulosique traitée et appareillage électrique l'utilisant

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US319387A US3313879A (en) 1963-10-28 1963-10-28 Treated cellulosic material and electrical apparatus embodying the same

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US3313879A true US3313879A (en) 1967-04-11

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US319387A Expired - Lifetime US3313879A (en) 1963-10-28 1963-10-28 Treated cellulosic material and electrical apparatus embodying the same

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US (1) US3313879A (no)
ES (1) ES304909A1 (no)
GB (2) GB1083557A (no)
NO (1) NO115591B (no)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4268810A (en) * 1978-07-31 1981-05-19 Sumitomo Bakelite Company Limited Electrical article having electrical coil and method for manufacturing same

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2086418A (en) * 1934-09-04 1937-07-06 Du Pont Treatment of cellulosic bodies
US2577593A (en) * 1946-12-21 1951-12-04 Du Pont Stabilizing cellulose yarns
US2627504A (en) * 1948-07-14 1953-02-03 Monsanto Chemicals Dielectric containing halogenated aromatic hydrocarbon and mono ortho tolyl biguanide as corrosion inhibitor
US2806190A (en) * 1952-11-06 1957-09-10 Sprague Electric Co Low power factor capacitor
US2991326A (en) * 1957-12-24 1961-07-04 Westinghouse Electric Corp Insulation system for electrical apparatus containing liquid dielectrics
US3102159A (en) * 1962-03-23 1963-08-27 Westinghouse Electric Corp Treated cellulosic material and electrical apparatus embodying the same
US3135627A (en) * 1961-08-08 1964-06-02 Mc Graw Edison Co Thermally stabilized cellulose materials for electrical insulation

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2086418A (en) * 1934-09-04 1937-07-06 Du Pont Treatment of cellulosic bodies
US2577593A (en) * 1946-12-21 1951-12-04 Du Pont Stabilizing cellulose yarns
US2627504A (en) * 1948-07-14 1953-02-03 Monsanto Chemicals Dielectric containing halogenated aromatic hydrocarbon and mono ortho tolyl biguanide as corrosion inhibitor
US2806190A (en) * 1952-11-06 1957-09-10 Sprague Electric Co Low power factor capacitor
US2991326A (en) * 1957-12-24 1961-07-04 Westinghouse Electric Corp Insulation system for electrical apparatus containing liquid dielectrics
US3135627A (en) * 1961-08-08 1964-06-02 Mc Graw Edison Co Thermally stabilized cellulose materials for electrical insulation
US3102159A (en) * 1962-03-23 1963-08-27 Westinghouse Electric Corp Treated cellulosic material and electrical apparatus embodying the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4268810A (en) * 1978-07-31 1981-05-19 Sumitomo Bakelite Company Limited Electrical article having electrical coil and method for manufacturing same

Also Published As

Publication number Publication date
NO115591B (no) 1968-10-28
ES304909A1 (es) 1965-04-01
GB1083557A (en) 1967-09-13
GB1094884A (en) 1967-12-13

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