Abstract: A dry, highly flexible, porous, essentially solvent free mica insulation tape is made, containing a curable, resinous, bonding composition containing polybutadiene containing from 70 weight percent to 100 weight percent of 1,2-polybutadiene, and catalyst, where the tape contains from 2 weight percent to 15 weight percent of polybutadiene based on the total weight of the resin bonded tape, and where the tape is capable of subsequent impregnation by an impregnating resin.

Abstract: A splice between two multiconductor cables is protected from ingress of water by a closure which is filled with a sealant which is pressurized by a bladder inside the closure to a pressure sufficient to force the sealant into the interstices of the splice and the interstices between the conductors in the cable, and the pressure is maintained by the bladder until the sealant cures or hardens.

Abstract: A method for improving the electrical insulation of an electrode in a power transformer included in a converter plant of a high voltage direct current (HVDC) transmission system. The method involves winding around the electrode, layers of tape of woven or non-woven fibrous structure of non-conducting cellulose material, inorganic plastics material, or inorganic insulating material. This means that ions approaching the electrode, which are migrating under the influence of a high d.c. field outside the electrodes, do not sense the porous tape insulation as any noticeable obstacle, while at the same time the insulating layer is sufficiently dense to increase the breakdown value in the case of electrical surges.

Abstract: A method of forming a molded encapsulation around a sealed spliced region between two cables in which the cables pass through a mold with the splice region in the mold cavity and correctly centered before molding. To allow for the centering operation to be performed, apertures are provided in the mold. Hook members are passed through the apertures. These hook members are caused to engage both inner and outer mold surfaces and they also engage tie means at two circumferentially spaced positions around the splice region to centralize the region within the cavity. The mold is then filled with molten material and the hooks removed from the apertures with the material still molten. Hook removal may take place either when the cavity is completely filled or after sufficient molten material has entered the mold to hold the splice region in fixed position. The method is applicable to low pressure molding, i.e. below 100 psi and preferably below 50 psi.

Abstract: Magnet wire insulated with dielectric tape material of polyester overwrapped with aromatic polyamide is described. The tape can be spirally wrapped at high speeds onto the magnet wire substrate. The initial layer of polyester provides secure bonding of the subsequently wrapped polyamide layer. The wire is particularly useful in environments where abrasion resistant, high temperature stable magnet wire is needed which is capable of submersive use in oil and maintains its integrity when exposed to other corrosive environments.

Abstract: An apparatus and method for making an armored electrical cable from a plurality of reinforcing struts and a plurality of electrical conductors covered by an armored jacket. The apparatus includes a series of stations along an assembly line that feed, converge, orient, combine, compress and wrap the struts and conductors into the cable configuration. The cross section of the cable so formed is rectangular, although this rectangular shape can be made arcuate by bending.

Abstract: A relatively small pair size cable (20) comprising at least one conductor (22) which is insulated with polyvinyl chloride plastic material is provided with a flame retardant, smoke suppressive non-metallic sheath system (30). The sheath system has a relatively low thermal conductivity and provides a predetermined delay prior to the thermal decomposition of the conductor insulation. It includes an inner layer (31) of an aramid fibrous material which has a relatively high compressibility, a relatively low heat absorptivity, and a relatively low air permeability. The inner layer is enclosed by an outer jacket (40) of a fluoropolymer plastic material which is extruded about the inner layer.

Abstract: Melt-fusible polyimides based on pyromellitic dianhydride and at least one defined aromatic diamine are useful in making low-void composites and thermoplastic tapes, which can be fabricated into articles such as, for example, aircraft and autobody panels, printed circuit boards, etc. Some of these polyimides are melt-processible and can be fabricated by conventional procedures such as extrusion and injection molding.

Abstract: A reinforced insulated electrical cable and a method of forming the cable, which is especially useful in oil wells. The reinforcement comprises a thin tape of thermosetting material imbedded with an open-mesh fabric, the tape being spirally wrapped directly around the cable's insulation. The tape is wrapped in unvulcanized form and is then vulcanized in place over the insulation. The layer of open-mesh fabric is spaced from the outer surface of the insulation so that, during vulcanization, the insulation can radially outwardly expand without contacting and thus deforming the fabric, and at the same time the insulation can push part of the thermosetting material through the spaces in the fabric.

Abstract: A flexible lightweight short pulse power cable assembly for electrical power transmission, e.g., for transmission of electrical power at 20,000 volts at short pulse D.C. halfwave currents of 30,000 amperes. The cable for electrical transmission utilizes an inner conductor and an outer concentrically disposed conductor, the inner and outer conductors having substantially equal cross-sectional areas and consequent resistances to equal and opposite current flows in the respective conductors thereby placing the cable current forces in compressive balance and further reducing electro-magnetic interference from transmission of power through the cable.

Abstract: A flat communication cable is formed of an assembly of standardized modules in edge-to-edge relation surrounded by an overlying polyester protective cover. The modules containing a PVC jacket are united to form a ribbon by a blend of fusion and hot melt adhesive material, and the protective cover is bonded thereto by the adhesive. The modules can contain polyolefin insulated wire pairs, coaxial electrical conductors, stranded or solid wire, fiber optic filaments, or the like. Semiconductive or non-conductive material can be incorporated in the PVC jacket of the modules and/or the adhesive as desired and in any combination. Drain wires can be included. Also, the cover material can include metallic layers for shielding.

Abstract: A splice between at least two multi-wire electric cables is protected from ingress of water by forming a compressible reservoir about the splice, filling the reservoir with a curable liquid sealant, compressing the reservoir to force the liquid sealant to penetrate into the interstices between the individual wires of the splice bundle and into the adjacent cable core and maintaining the reservoir under compression at least for a time sufficient for the sealant to cure.

Abstract: A thin, flexible, electrically conductive adhesive tape is described suitable for do-it-yourself wiring in low voltage applications including a pair of longitudinally extending parallel electrical conductors each made of a multiplicity of strands of wire enclosed within a backing strip. The backing is paper-thin and can comprise a pair of layers of transparent or translucent plastic material bonded together around the conductors or a single thickness within which the conductors are embedded, the backing being formed for example by co-extrusion of upper and lower layers which are brought together while still in a molten condition so as to fuse together totally enclosing the wires. A stripable cover sheet is preferably provided over a pressure sensitive layer on one surface of the tape. The tape can be separated longitudinally into two tape strips by the provision of a central longitudinally extending line of perforations.

Abstract: A method of manufacturing a molded coil for use in an electric apparatus such as a molded transformer or a reactor. The method includes the steps of covering a winding with an insulating prepreg, curing the prepreg under heat, and casting a synthetic resin around the prepreg. The method makes it possible to minimize any thermal stress that may develop in the molded resin layer.

Abstract: An apparatus and method for producing an insulated connection between a pair of insulated electrical cables by means of curing uncured insulation wrapped around joined conductors in the cables. The apparatus comprises a multiple part mold assembly having a cylindrical cavity, mechanisms for heating and cooling the mold parts and an assembly for creating a radially inwardly directed, substantially constant pressure on the curing insulation while allowing radial expansion and contraction of the insulation and mold parts during heating and cooling. The pressure-creating assembly comprises a pair of rectilinear power devices and a pair of cables wrapped around the mold parts and tensioned by the power devices, this assembly applying a radially inwardly directed, equal and substantially constant force to the mold parts. Preferably, the mold assembly comprises three equal parts, each defining one-third of a cylindrical body and each having rollers on the outer surface for receiving the cables therein.

Abstract: An armored cable and a method of manufacturing an armored cable, said cable having a helically wrapped zinc-plated steel armor. The steel armor band has zinc protective layer on its two sides, and uncoated edges, to reduce manufacturing costs and improve cathodic protection. The zinc protective layer thereby comprises a first layer portion consisting of a zinc-iron alloy and a second layer portion, on top of said first layer portion consisting of essentially pure unalloyed zinc and having a thickness of at least 90% of the total layer thickness.

Abstract: A process and apparatus for filling multi-conductor cables, particularly a telecommunication cable with several insulated wires surrounded by a covering and a sheath, with a mixture of powders which expand with the absorption of moisture. The conductors are fed in spaced relation into the entrance of a casing having an interior, frusto-conical wall which decreases in diameter from its entrance to its exit. The exit is small in diameter compared to the entrance so that the conductors converge as they pass from the entrance to the exit. Intermediate the entrance and the exit, the conductors are subjected to the powders which are caused to follow a helicoidal course by a screw which directs them toward the exit. Due to the shape of the casing wall, the powders are forced toward the conductors.

Abstract: A multiple joint box having a socket pipe and sealing bodies, the sealing bodies comprising spirally wound tape having semicircular recesses formed along its length which coincide to form circular cable apertures. The multiple joint box may be applied without the necessity of cutting or desplicing the cable.

Abstract: There is presented various methods and articles utilizing heat shrinkable and heat sealable sheets, films and materials.

Abstract: A method of insulating an electromagnetic coil comprises the steps of wrapping first and second overlapping layers of fluorinated ethylene propylene (FEP) resin-coated polyimide tape around distal sections of the end turns of the coil, inserting conforming laminae of FEP resin-impregnated glass cloth between adjacent coil turns, wrapping at least two overlapping layers of FEP resin-coated polyimide tape around the entire coil, heating the coil to at least the resin melting point, applying pressure to compress the tape and laminae and to clamp together the respective turns of the coil, and finally cooling the coil under pressure to allow the resin to resolidify. The resulting product has a thin, uniform coating of impervious electrical insulation characterized by improved heat transfer capability and improved stability at high temperatures.

Abstract: Methods and apparatus for forming a cable element comprising a core of plastic material with helical surface grooves containing one or more optical fibers. The core has one or more reinforcing elements resistant to tension and compression and is covered with a covering of tape or thermoplastic. The core is fed to a rigid body having tongues corresponding to and entering into the grooves, and the optical fiber or fibers are fed into the grooves through through-holes in the body which extend from the exterior surface of the body to the tongues and which are inclined with respect to the axis of the core. The core feeding means may be a pay-off bobbin or a core extruder with a threading die, and by increasing the feed rate of the fibers relative to the feed rate of the core or by stretching the core in advance of the rigid body, the lengths of the fibers in the grooves may be longer than the lengths of the grooves.

Abstract: A system for applying insulating tape to a three-dimensionally curved conductor, particularly of the type used in high voltage applications. A wrapping ring having an axis of rotation is oriented with respect to the conductor such that the axis of rotation is always placed on the spinning point of the insulating tape, the spinning point being at the location where the tape tangentially contacts the conductor during wrapping. Such an orientation of the wrapping ring avoids the formation of pockets at the curved places of the conductor.

Abstract: An improved sheathed cable and method for producing same is described. The cable includes an inner insulated conductor/conductor group, an outer corrugated metal sheath, and a barrier layer of a pliable, inert sealing material disposed therebetween to prevent the passage of gas or vapors via the cable. The method includes the steps of applying the pliable material around the inner insulated conductor/conductor group, wrapping the pliable material with a flexible tape, forming an outer metallic sheath around the material, and making annular corrugations in the outer sheath so as to compress the sealing compound.

Abstract: A flexible mica tape having a low gel time is prepared from a composition of an epoxy resin, an organotin salt, and catechol or pyrogallol. A mica sheet is immersed in the composition and the solvent is evaporated to form a tack-free A-staged resin. A conductor is wound with the tape and is impregnated with an impregnating resin using vacuum-pressure impregnation.

Abstract: A method of reconstituting an external conductor of a coaxial cable which stands up well to bending and has good electromagnetic propagation. Solid non-perforated or woven strips are wound in a helix along the whole length of the part which is to be repaired and the ends of the intact external conductor and said strips are glued on these ends with an electrically conductive glue. Application to coaxial telephone cables.

Abstract: The present invention relates to a method of manufacturing a flexible electric cable with a tinned stranded conductor on which insulation is applied at a high temperature. Previous diffusion of tin in the copper of the conductor strands makes it possible to prevent the strands from blocking together while the insulation is being formed at a temperature higher than the melting point of tin, while still leaving a final layer of pure tin at the surface of these conductor strands. Application to manufacture of aircraft cables.

Abstract: The conductors of a cable core unit are powder filled by passing the core unit through a fluidized bed of powder with the conductors substantially closed together. The filled cable core unit can be wrapped with tape after exit from the fluidized bed. Cable cores may be filled also by passing them through a fluidized bed. The core units of the cores may be closed together or separated, but the conductors of each unit are closed together.

Abstract: Electrical insulation for an elongate current carrying body, e.g. an underwater cable for carrying very high voltages, is provided by winding a tape round the body under tension, the tape being made of a film of an axially orientated polymer having a thickness less than 200 microns, and preferably between 10 and 50 microns, a significant degree of crystalline order, a high tensile strength, a high modulus of elasticity, and the ability to cling to itself.

Abstract: Electric windings comprising an electric conductor and a plurality of cured insulating layers wrapping around the conductor, said cured insulating layers being obtained by bonding two or more insulating materials with a binder solution containing a mixture of a condensation polymerization type silicone resin containing hydroxyl groups in the molecule and an addition polymerization type silicone resin to form a composite insulating material, wrapping the composite insulating material around the conductor, impregnating the wrapped composite insulating material with an impregnating varnish of an epoxy-isocyanate resin and curing the impregnated composite insulating material, have excellent water resistance in addition to excellent thermal resistance, and mechanical properties.

Abstract: An improved method for producing sheathed cable which includes an inner insulated conductor/conductor group, an outer corrugated metal sheath, and a barrier layer of a closed-cell foam disposed therebetween to prevent the passage of gas or vapors via the cable. The method includes the steps of wrapping a strip of heat activated closed cell foam about the insulated conductor, forming an outer sheath around the foam, and activating the foam to fill the space between the inner and outer sheaths. In accordance with varying alternative embodiments of the invention, the barrier strip may be continuous or interrupted; and/or may comprise an already foamed material compressed by formation of the outer metallic sheath.

Abstract: High-voltage insulation in which mica tape employing a binder resin is used for wrapping around electrical apparatus, and the wrapped apparatus is impregnated with a heat-setting epoxy resin. The binder resin for the mica tape is a polyester containing a tertiary-bound nitrogen which is effective as an adhesive for the tape and also as an accelerator for the epoxy resin.

Abstract: An optical glass having a high dispersion and a refractive index in the range of from 1.53 to 1.86 and an Abbe number in the range of from 21 to 43 comprises substantially the following components in percent by weight:P.sub.2 O.sub.5 : 10-72R.sup.I.sub.2 O: 0-41ZnO: 0-46(provided that R.sup.I.sub.2 O + ZnO: 5-50)Nb.sub.2 O.sub.5 : 22-63wherein R.sup.I.sub.2 O is Li.sub.2 O, Na.sub.2 O or K.sub.2 O or combination of two or more thereof.

Abstract: A superconductor structure with a stabilized superconductor, is surrounded by a jacket of a reinforcement material, comprising a preprofiled metal sheet which is bent around the superconductor and contains strip-like zones which extend in the lengthwise direction of the conductor and are in contact with the superconductor, and strip-like zones in between which are spaced from the surface of the superconductor, with filler strips of predetermined thickness arranged in the channel like outer depressions of the jacket.

Abstract: The present invention relates to a laminated insulating paper formed of cellulose paper or papers which is adhered to at least one side of cross-linked silicone grafted polyolefine film and to an oil-filled (OF) cable which insulated by the laminated insulating paper. The laminated insulating paper has outstanding peel strength as well as excellent non-solubility and anti-swelling properties in insulating oils.

Abstract: A filament served bondable conductor is described. A metal wire is wrapped with an insulating yarn then suspended between two supports. After passing over the first support, the wire is immersed in a varnish, excess varnish is removed, and the varnish is cured in an oven before the wire passes over the second support. The wire is again suspended between two more supports. After passing over the third support the wire is immersed in an enamel, excess enamel is removed, and the enamel is cured to a non-tacky B-stage in the same oven. The wire can then be wound on a take-up reel until needed. The wire can be formed into coils and the coils heated to fuse and completely cure the enamel.

Abstract: A process for manufacturing a coaxial cable which exhibits a substantially uniform electrostatic capacity with respect to length. The improvement includes the steps of reheating the insulated layer and then recooling and resolidifying the reheated insulated layer. The improvement also includes the steps of feeding and then reducing the outer diameter of the inner conductor prior to the winding of the rib onto the outer peripheral surface of the inner conductor.

Abstract: Electrical insulating sheet material characterized by a coating of thermosetting resinous adhesive material distributed over two sides of a sheet of aramid paper, in combination with a pattern of pressure sensitive adhesive material applied to one side of the aramid paper sheet.

Abstract: Electric machine windings produced by wrapping a composite insulating material around an electrical conductor, said composite insulating material having been prepared by bonding two or more insulating materials with a silicone resin containing hydroxyl groups in the molecular structure, impregnating said composite insulating material with an insulating varnish comprising 1 equivalent of a polyfunctional epoxy compound and 2.5 to 25 equivalents of a polyfunctional isocyanate compound and curing said varnish, have excellent insulation properties under high temperatures and high humidity and thermal resistance of class H or more.

Abstract: A stress-relieving material for the surface of an insulated electrical conductor consists essentially of a cold-flowable, low viscosity, corona-resistant elastomer containing from about 350 to about 600 parts by weight per hundred of elastomer of a semiconductor material and up to about 10 parts per hundred of elastomer of processing aids.

Abstract: The proposed method for insulating the covering of cables resides in high-frequency heating of the cable conductor wrapped with tapes from polymer materials, such as polyimidepolytetrafluoroethylene films, in a transverse magnetic field over a period of time required to reach the material softening temperature and maintaining this temperature until the polymer material is baked, which is done in a longitudinal magnetic field. The device for carrying out the above method comprises an induction loop heater and a cylindrical induction heater arranged coaxially therewith. The invention can most advantageously be used to provide for quality insulation of cables up to 70 sq. mm in cross section.

Abstract: A solventless impregnating composition is disclosed which is made by forming a mixture of a liquid diepoxide and about 10 to about 80 phr of a diglycidyl ether of a glycol. To this mixture is added a titanate catalyst in an amount sufficient to cure the composition.

Abstract: A pushpull cable conduit is made by continuously moving a tubular mandrel through a crosshead extruding die, forming a tape of micro-porous polytetrafluoroethylene resin into cylindrical form covering the mandrel as it enters the extruding die, extruding an outer layer of fluid polymeric material over the cylindrical covering in the presence of heat, helically wrapping contiguous wires over said outer layer to form a wire layer, extruding an outer covering of thermoplastic material over the wire layer, and removing the tubular mandrel. The porosity of the polytetrafluoroethylene covering insures a good heat bond with the outer layer of fluid polymeric material and also provides a lubricant reservoir in its inner surface, thereby minimizing friction with the cable core and greatly reducing sound transmission.

Abstract: In the connection or terminal portions of cross-linked polyethylene cables produced by winding irradiated tapes around the connection or terminal portions of cross-linked polyethylene insulated cables and heat molding the same, the irradiated tapes comprise polyethylene and/or an ethylene copolymer as a base resin plus an ethylene-vinyl acetate copolymer containing more than about 15% vinylacetate (VA) in an amount which provides more than an about 2.5% VA content in the irradiated tapes.

Abstract: A jointer for laminated tapes for use in the production of sheathed cables formed by longitudinally or helically wrapping cable cores with metal tapes laminated with plastic films and by joining the overlapped portions of said tapes by way of heat fusion is disclosed. The method comprises the use of pressing blocks consisting of metal material having a high heat conductivity and respectively having machined surfaces opposing in parallel to each other for the application of uniform pressure to both surfaces of the laminated tapes held therebetween. A heating piece is provided which is electrically insulated from and mounted to the bottom of the pressing block and having relatively high electric resistance and being supplied with electric current thereby pulse heating the portions of the laminated tapes to be spliced.

Abstract: A radiation resistant cable is made by wrapping a barrier film over a conductor and covering it with a silicone saturated asbestos covering. The asbestos is passed through one or more dies to compact the asbestos covering and accurately size it. One or more layers of polyimide tape is wrapped about the asbestos. The polyimide tape is covered by a heat-sealable tape over which a fiberglass cover is braided. The cable is then heated to seal the heat-sealable tape to itself as well as to the adjacent layers. The cable is then passed through a coating bath to impregnate and saturate the fiberglass braid, following which the cable is heated to extract the solvent in the coating solution.

Abstract: A compound mica sheet is prepared by bonding a mica sheet to a woven fabric through a powdered epoxy resin with curing agent. The mica sheet holds a cured thermosetting resin composition impregnated therein and has an uncured epoxy resin composition including a curing agent impregnated therein. When thermosetting resin is forcedly impregnated, through vacuum/pressure impregnation, into a coil wound with the compound mica sheet which is adapted for use in medium and high voltage electric apparatus, and then cured, an excellent insulated coil is obtained.

Abstract: A rotatable assembly is rotatably mounted on a stationary assembly. The stationary assembly guides a conductor wire, or the like, to a wrapping station, the rotatable assembly applying glue or other adhesive to a portion of a wrapping tape which is wrapped around the conductor wire at the wrapping station. The glue is applied to the wrapping tape by supplying it to a receptacle in the rotatable assembly, from which it is forced out through a hole by centrifugal force. The receptacle is of conical shape so that the centrifugal force acting on the glue will have a component thereof forcing the glue up toward the hole, and out therefrom.

Abstract: A flexible, nontacky prepreg for use in bonding high voltage coils and inner cooling channels which comprises a fibrous mat material containing a high molecular weight epoxy and a sterically hindered anhydride. The resin comprises approximately 25 to 500% by weight of the fibrous mat material.

Abstract: A multi-layer insulation for deep-cooled cables utilizing insulating foils having a dielectric loss factor less than 5.times.10.sup..sup.-5 in which a layer of a spun bonded paper of high density polyethylene fibers is placed between each two layers of insulating foil thereby providing sufficient elasticity even when the cable is cooled to a very low temperature to equalize expansion differences occurring in the cable.

Abstract: A binding tape is made by coating a ribbon having glass fibers in the fill direction and a flexible, thermally stable fiber in the warp direction, with a swellable resin composition and removing the excess composition. The tape is lap-wound over an electrical conductor which is then immersed in solventless resin under pressure. The conductor is removed from the solventless resin and the tape prevents the solventless resin from seeping out before it is cured.