US3261910A - Electrical strain insulator and method of making same - Google Patents

Electrical strain insulator and method of making same Download PDF

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Publication number
US3261910A
US3261910A US389104A US38910464A US3261910A US 3261910 A US3261910 A US 3261910A US 389104 A US389104 A US 389104A US 38910464 A US38910464 A US 38910464A US 3261910 A US3261910 A US 3261910A
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United States
Prior art keywords
end pieces
connecting piece
strain insulator
diameter
support element
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Expired - Lifetime
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US389104A
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English (en)
Inventor
Jacquier Michel
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Alcatel Lucent SAS
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Compagnie Generale dElectricite SA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B17/00—Insulators or insulating bodies characterised by their form
    • H01B17/32—Single insulators consisting of two or more dissimilar insulating bodies

Definitions

  • Strain insulators are already known which comprise two metallic end pieces provided with anchoring means. The end pieces are linked together by a connecting piece formed of filiform elements such as glass fibers bound together by a resin.
  • a connecting piece formed of filiform elements such as glass fibers bound together by a resin.
  • none of these known strain insulators presents the advantages corresponding to the high characteristics of their components. This is due to lthe fact that glass fibers present a low lstretch index and a low resistance to shearing stresses, and that in the prior strain insulators the problem of securing the metallic end pieces to the connecting piece has not been solved satisfactorily. It is the purpose of this invention to obvlate such disadvantages. p
  • One embodiment utilizing the principles of this invention provides a method of making strain insulators comprising -two metallic end pieces each provided with a shoulder forming portion and a connecting piece; joining these end pieces such that iiliform elements assembled 1n strands are wound and stretched around said shoulders and the'connecting piece So as to forma wrapping or sleeve comprising a cylindrical portion terminating at both ends in a cap, the shape of which approachesthat of a portion of a sphere.
  • the particular shape of the shoulders is the most important feature which renders possible the making of strain insulators, presenting a very high linear strength.
  • the most advantageous shape of the shoulders is a composite shape of a portion of a sphere and of a portion of ellipsoid, the revolution axis of which is the longitudinal axis of the strain member.
  • FIG. 1 is a longitudinal sectional View of a support element supporting the winding of the strain insulator of the invention.
  • FIG. 2 is a longitudinal sectional view of the strain insulator ofthe invention.
  • reference numerals 2 and 3 designate two metallic end pieces partly engaged with a tube or connecting piece 1 and forming with the latter a cylindrical rod having two shoulders 4 and 5.
  • the end pieces 2 ⁇ and 3 also include anchoring portions 6 and 7.
  • Tube 1 is filled with an insulating material 12 which can be in a gaseous, liquid or solid state.
  • the shoulders 4 and 5 have preferably a shape which is intermediate between a spherical and ellipsoidal shape, the revolution axis of which is the longitudinal axis of the strain insulator.
  • the support-element formed by the two end pieces and ⁇ the connecting piece is provided with a wrapping or sleeve 8 made of a fiber glass roving continuously wound back and forth from end to end of said support-element.
  • the winding process is executed as follows:
  • the support-element is disposed on a holder located in front of a winding machine supplied 3,261,910 Patented July 19', 1966 ICC with fibrous strands.
  • the end of a strand is secured, by any known means, yto the support-element.
  • the support-element is rotated while the strandis regularly, rapidly and continuously displaced from one extreme end to lthe other end of the support-element.
  • the roving is wound in very long pitched spirals, thus forming a cylindrical sheet of wound strands ending in two caps of superimposed strands upon -the shoulders, each strand following a geodesic curve on said shoulders.
  • the strands have no tendency to be displaced on the shoulders 4 and 5 since there is no lateral gliding force component, owing to the fact that the strands follow geodesic curves on the shoulders. Further, the shearing stresses are reduced to a minimum value and use is made of the most interesting property of the glass fibers, i.e. their tensile strength. Such an arrangement allows a reduced thickness of the fiber layer for a given strain resistance per mm?.
  • strain insulators comprising a thick ysleeve constituted of an important number of superimposed sheets of fiber strands.
  • the inner and outer fibers work under different tensile stresses and the thicker the sheet the greater the difference between the stresses applied to the inner and outer strands respectively.
  • the thickness of the roving wound on the support is only of about one-tenth of lthe diameter of tube 1, which serves as a mandrel, and ⁇ this gives the greatest tensile strength to the strain insulator. It should be noted that to obtain the best result, the pitch of the winding should be as long as possible. This is obtained by adjusting the rotary speed of the support element in function of the diameter and length of said support element.
  • the filiform elements used in such a winding can be coated with lthermosetting resin in order to bind together -the turns of the winding after polymerization.
  • This coating can be applied before, during, or even after the winding process. It is also advantageous to use untwisted fibrous strands having a diameter under l0 microns. Polyester or epoxy resin with their usual adjuvants may be used as thermoset-ting resins.
  • the coating resin liber glass weight ratio is advantageously comprised between 10% and 30%, the recommended ratio being around 20%.
  • strain insulator is located in an insulating fluid medium, it is possible either to omit coating the fibrous strands or to provide such a coating only on a par-t of the winding, for example, on the end portions of the strain insulator.
  • the tube 1 is made by winding glass fibers on a mandrel, said fibers being wound with the same pitch and bound with the same coating as sleeve or wrapping 8.
  • a more close connection is obtained ybetween the sleeve 8 and the support-element 1 eliminating the risk of any striking of electric arc in the medium constituting the junction between Isaid sleeve and said support element.
  • the glass fiber of the winding constituting tube 1 has a section under 10 microns.
  • Two channels 9 and 10 pass through the metallic end pieces 4 and 5, and the inside of the tube 1 is filled through the channels 9 and 10 with an insulating medium 11 which adheres on the inner surface of the tube 1.
  • a strain insulator manufactured according to the method of this invention presents a tensile strength higher than kg./mm.2 for the wound part of the insulator, i.e. a strain insulator having an overall diameter of only S cm.
  • such insulator is capable of sustaining the stresses imposed by a 28 ton load.
  • insulator can resist, without destructive breakdown, a high voltage such as the passing round arc voltage.
  • the strain insulator can include discharge guards regularly spaced along the cylindrical part of the member secured to the latter by sticking, or incorporated among the strands of the winding.
  • the strain insulator may be coated with resin which is not affected by the thermic effect of an electric arc, for example, a resin including polytetrauoroethylene. It is also possible to dispose the strain insulator within an insulating casing made of a ceramic. Suitable means are provided for ensuring the tightness of the sealing joints disposed between said casing and the ends of the strain member and the insulating material filling the space between the casing and the strain insulator. Further, the tube 1 may be replaced by a rod provided at both the ends with a recess wherein the end pieces are partly engaged.
  • An electrical strain insulator comprising two metallic end pieces each provided with a shoulder forming portion of substantially hemispherical shape, a connecting piece joining said end pieces, said end pieces and connecting piece forming a support element, a fiber glass roving having a strand diameter substantially smaller than the diameter of said connecting piece wound around said support element and forming a wrapping of substantially uniform thickness, said fiber glass having a long pitch spiral and following the geodesic lines on said shoulders for securing together said end pieces and said connecting piece.
  • An electrical strain insulator comprising two substantially hemispherical end pieces terminating at their apices in an anchor forming shank portion, a cylindrical connecting piece having substantially the sarne diameter as said end pieces disposed therebetween for forming therewith a support element, -a fiber glass roving having a strand diameter substantially smaller than the diameter of said connecting piece wound around said support element with a longitudinal pitch and following the geodesic lines on said end pieces, said roving having a substantially uniform thickness for covering and securing together said end pieces and said connecting piece.
  • An electrical strain insulator comprising two substantially hemispherical end pieces each having at their apieces an anchor forming shank portion, and at their opposite sides a -cylindrical stepped portion of reduced diameter, a cylindrical connecting piece having substantially the same diameter as said hemispherical end pieces and provided at both ends with an opening having substantially the same diameter as said cylindrical stepped portions, each end piece being engaged in one of said openings by its stepped portion, said end pieces and said connecting piece forming a support element, a fiber glass roving having a strand diameter substantially smaller than the diameter of said connecting piece wound around said support element with a longitudinal pitch and following the geodesic lines on said end pieces, said roving having a substantially uniform thickness for covering and securing together said end pieces and said connecting piece.

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US389104A 1963-08-20 1964-08-12 Electrical strain insulator and method of making same Expired - Lifetime US3261910A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR945145A FR1378902A (fr) 1963-08-20 1963-08-20 Procédé de fabrication d'un barreau d'ancrage à haute résistance mécanique et électrique et barreau ainsi obtenu

Publications (1)

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US3261910A true US3261910A (en) 1966-07-19

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FR (1) FR1378902A (fr)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3839593A (en) * 1972-09-04 1974-10-01 Ceraver Tubular insulating connector formed of wound glass wires
FR2505915A1 (fr) * 1981-05-12 1982-11-19 Ceraver Procede de fabrication d'un isolateur de hauban de type composite
US4491687A (en) * 1981-08-05 1985-01-01 Societe Anonyme Dite: Ceraver Method of manufacturing a composite type stay insulator, and an insulator obtained by the method
US4495381A (en) * 1982-09-30 1985-01-22 General Electric Company Dynamic load bearing transmission line support member
US4656555A (en) * 1984-12-14 1987-04-07 Harvey Hubbell Incorporated Filament wrapped electrical assemblies and method of making same
US4899248A (en) * 1984-12-14 1990-02-06 Hubbell Incorporated Modular electrical assemblies with plastic film barriers
US4905118A (en) * 1988-03-31 1990-02-27 Hubbell Incorporated Base mounted electrical assembly
US5092713A (en) * 1990-11-13 1992-03-03 Conoco Inc. High axial load termination for TLP tendons
US5138517A (en) * 1984-12-14 1992-08-11 Hubbell Incorporated Polymer housed electrical assemblies using modular construction
US6008975A (en) * 1997-03-03 1999-12-28 Mcgraw-Edison Company Self-compressive surge arrester module and method of making same
US6034330A (en) * 1998-03-10 2000-03-07 Pratt; Hugh Michael Load insulator
US20030231097A1 (en) * 2002-06-16 2003-12-18 Victor Almgren Composite insulator for fuse cutout
US20040001298A1 (en) * 2002-06-16 2004-01-01 Scott Henricks Composite insulator
US20040084204A1 (en) * 2002-07-18 2004-05-06 Sediver, Societe Europeenne D'isolateurs En Verre Et Composite Making a composite insulator body
US20050000722A1 (en) * 2003-07-02 2005-01-06 Abb Research Ltd Shaft, method for producing it and device for carrying out the method
US20050199418A1 (en) * 2004-03-15 2005-09-15 Abb Research Ltd. High voltage bushing with field control material
US7028998B2 (en) 2001-04-30 2006-04-18 Maclean-Fogg Company Stabilizer bar
US7041913B2 (en) 2000-12-26 2006-05-09 Barker Jr James W Method and arrangement for providing a gas-tight housing joint

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2199609A1 (en) * 1972-09-20 1974-04-12 Daguier Maurice Insulating couplings for transmitter aerial supports - comprising filament reinforced resin couplings loaded in tension

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US706194A (en) * 1902-05-26 1902-08-05 Louis Mccarthy Insulator.
US735611A (en) * 1903-01-14 1903-08-04 Louis Steinberger Spheroidal strain.
US1170723A (en) * 1914-03-02 1916-02-08 Ohio Brass Co Strain-insulator.
GB138539A (en) * 1919-06-11 1920-02-12 Lutz Hans Improvements in electric insulators
US1730327A (en) * 1918-06-28 1929-10-01 Westinghouse Electric & Mfg Co Insulator
FR1040850A (fr) * 1951-07-13 1953-10-19 Cie Generale Electro Ceramique Perfectionnements aux isolateurs pour haute tension
US2723705A (en) * 1950-07-21 1955-11-15 Owens Corning Fiberglass Corp Method and apparatus for making reinforced plastic laminates
US2732423A (en) * 1956-01-24 morrison
GB775773A (en) * 1954-06-23 1957-05-29 British Insulated Callenders Improvements in or relating to insulators for high tension overhead electric power lines
GB821101A (en) * 1955-03-22 1959-09-30 Saint Gobain Electric insulators
US2924643A (en) * 1955-10-03 1960-02-09 Bullard Co Insulated tension link and method of making same
GB915052A (en) * 1958-02-18 1963-01-09 British Insulated Callenders Improvements in or relating to electrical insulators

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2732423A (en) * 1956-01-24 morrison
US706194A (en) * 1902-05-26 1902-08-05 Louis Mccarthy Insulator.
US735611A (en) * 1903-01-14 1903-08-04 Louis Steinberger Spheroidal strain.
US1170723A (en) * 1914-03-02 1916-02-08 Ohio Brass Co Strain-insulator.
US1730327A (en) * 1918-06-28 1929-10-01 Westinghouse Electric & Mfg Co Insulator
GB138539A (en) * 1919-06-11 1920-02-12 Lutz Hans Improvements in electric insulators
US2723705A (en) * 1950-07-21 1955-11-15 Owens Corning Fiberglass Corp Method and apparatus for making reinforced plastic laminates
FR1040850A (fr) * 1951-07-13 1953-10-19 Cie Generale Electro Ceramique Perfectionnements aux isolateurs pour haute tension
GB775773A (en) * 1954-06-23 1957-05-29 British Insulated Callenders Improvements in or relating to insulators for high tension overhead electric power lines
GB821101A (en) * 1955-03-22 1959-09-30 Saint Gobain Electric insulators
US2924643A (en) * 1955-10-03 1960-02-09 Bullard Co Insulated tension link and method of making same
GB915052A (en) * 1958-02-18 1963-01-09 British Insulated Callenders Improvements in or relating to electrical insulators

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3839593A (en) * 1972-09-04 1974-10-01 Ceraver Tubular insulating connector formed of wound glass wires
FR2505915A1 (fr) * 1981-05-12 1982-11-19 Ceraver Procede de fabrication d'un isolateur de hauban de type composite
EP0065227A1 (fr) * 1981-05-12 1982-11-24 CERAVER Société anonyme dite: Procédé de fabrication d'un isolateur de hauban de type composite
US4491687A (en) * 1981-08-05 1985-01-01 Societe Anonyme Dite: Ceraver Method of manufacturing a composite type stay insulator, and an insulator obtained by the method
US4495381A (en) * 1982-09-30 1985-01-22 General Electric Company Dynamic load bearing transmission line support member
US4899248A (en) * 1984-12-14 1990-02-06 Hubbell Incorporated Modular electrical assemblies with plastic film barriers
US5138517A (en) * 1984-12-14 1992-08-11 Hubbell Incorporated Polymer housed electrical assemblies using modular construction
US4656555A (en) * 1984-12-14 1987-04-07 Harvey Hubbell Incorporated Filament wrapped electrical assemblies and method of making same
US4905118A (en) * 1988-03-31 1990-02-27 Hubbell Incorporated Base mounted electrical assembly
US5092713A (en) * 1990-11-13 1992-03-03 Conoco Inc. High axial load termination for TLP tendons
US6008975A (en) * 1997-03-03 1999-12-28 Mcgraw-Edison Company Self-compressive surge arrester module and method of making same
US6034330A (en) * 1998-03-10 2000-03-07 Pratt; Hugh Michael Load insulator
US7180004B2 (en) 2000-12-26 2007-02-20 Maclean-Fogg Company Method and arrangement for providing a gas-tight joint
US7041913B2 (en) 2000-12-26 2006-05-09 Barker Jr James W Method and arrangement for providing a gas-tight housing joint
US7028998B2 (en) 2001-04-30 2006-04-18 Maclean-Fogg Company Stabilizer bar
US20030231097A1 (en) * 2002-06-16 2003-12-18 Victor Almgren Composite insulator for fuse cutout
US6831232B2 (en) 2002-06-16 2004-12-14 Scott Henricks Composite insulator
US20040001298A1 (en) * 2002-06-16 2004-01-01 Scott Henricks Composite insulator
US6822167B2 (en) * 2002-07-18 2004-11-23 Sediver, Societe Europeenne D'isolateurs En Verre Et Composite Making a composite insulator body
US20040084204A1 (en) * 2002-07-18 2004-05-06 Sediver, Societe Europeenne D'isolateurs En Verre Et Composite Making a composite insulator body
US20050000722A1 (en) * 2003-07-02 2005-01-06 Abb Research Ltd Shaft, method for producing it and device for carrying out the method
US7514635B2 (en) * 2003-07-02 2009-04-07 Abb Research Ltd Shaft, method for producing it and device for carrying out the method
US20050199418A1 (en) * 2004-03-15 2005-09-15 Abb Research Ltd. High voltage bushing with field control material
US7262367B2 (en) * 2004-03-15 2007-08-28 Abb Research Ltd High voltage bushing with field control material

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Publication number Publication date
FR1378902A (fr) 1964-11-20

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