Westinghouse Electric Corporation

Eaton Corporation

Northrop Grumman Systems Corporation

Siemens Westinghouse Power Corporation

Westinghouse Electric Company LLC

Karl F Schoch, Jr

James D Smith

Franklin T Emery

James D B Smith

Theodore R Vasilow

John Joseph Shea

Kenneth C Radford

John Bartko

Rajender K Sadhir

Wei-Fang A Su

Daryl V Stough

David C Grant

Deborah P Partlow

John H Thompson

Andrew J Piloto

Thomas V Congedo

Luciano C Scala

Robert A Boenning

Francis H Ruddy

Maurice H Hanes

Francis W Navish, Jr

Raymond J Bratton

Frederick G Geil

Selami Y Pusatcioglu

Stanwood L Anderson, Jr

Anthony P Barrett

Paul P Frank

Eileen M Wojtal

Daryl R Stough

Philip A Panackal

Xiaoyun Shirley Lai

Howard E Saudners

Thermal interface materials are essential for proper operation of electronic assemblies. They are used between surface mount components and printed wiring boards and between printed wiring boards and metal heat sinks. Their function is to bond the components together and allow good heat transfer between the parts being bonded. The approach disclosed in this invention is a fully-cured, flexible, filled elastomer that is coated on both sides with a partially cured, filled adhesive, which can be conveniently made by a low cost tape casting process. This unique approach offers a combination of good adhesion to both bonding surfaces, good heat transfer, compliance to accommodate mismatched coefficient of thermal expansion, rework capability, control of flow of the adhesive during cure, and easy handling of uncured material.

Thermal interface material for electronic assemblies

A process for making an improved current limiting composition comprising mixing an epoxy thermosetting resin containing more than one 1,2 epoxy groups per molecule with an acid anhydride curing agent, an epoxy reactive diluent, first and second co-accelerators and conductive additive particles to form a liquid mixture. The liquid mixture is heated at a first temperature range below gelation temperature while drawing a vacuum to drive off volatiles and gases. Continued heating at a second temperature range promotes gelation and heating a third temperature range effects a final cure. A first co-accelerator becomes effective during the gelation temperature range and a second co-accelerator does not become effective until the final cure temperature range. Gelation takes about 2 to 4 hours at about 130&deg; C. to 140&deg; C. and final cure takes about 13 to 18 hours at about 140&deg; C. to 160&deg; C. The epoxy resin is preferably a diglycidyl ether of bisphenol A, the epoxy reactive diluent is preferably a diglycidyl ether of neopentyl glycol, the acid anhydride hardener is preferably 1-methyl tetrahydrophthalic anhydride and the conductive additive particles are selected from the group consisting of carbon black, nickel fiber, nickel flake, nickel beads and copper flake. An effective amount of said alumina trihydrate is employed in the mixture to prevent dielectric breakdown, arcing and carbon tracking under high voltage conditions in current limiting compositions. The first co-accelerator is 1-methyl imidazole and the second co-accelerator is chromium acetylacetonate.

Process for making a positive temperature coefficient conductive polymer from a thermosetting epoxy resin and conductive fillers

An electrically conducting member (,) is insulated with a thin coating (,) of a resinous insulation composition containing a resin interactive with and bonded to an oligomer containing a metal of at least one of Cr, Sn and Zn, where the oligomer is within a silicate type mica or clay structure.

Superdielectric high voltage insulation for dynamoelectric machinery

Methods of preparing ferrite powders for use in microwave elements such as isolators, circulators, phase shifters and transmission line elements. In one method separate precipitations of metal dicarboxylate salts such as oxalates or malonates are mixed with a ferrous dicarboxylate. This is followed by mixing and calcining of the precipitated dicarboxylates to form the ferrite powder. In another method metal acetates in a solution of concentrated acetic acidare mixed with iron powder to form a solution which is mixed with malonic acid. The resulting mixed metal malonates are processed into a powder which is calcined to obtain the ferrite. To form a lithium ferrite, lithium carbonate is added to prepared powders prior to the calcining step.

Method for preparation of ferrites

A catalyzed mica tape used in insulating electrical conducting devices is made from a mica paper bonded to a backing with a bonding resin. The bonding resin is cross-linkable by an addition reaction. The catalyzed mica tape has distributed therein at least a catalyst at a concentration of greater than 0.01 g/m.sup.2 for every 100 g/m.sup.2 of the bonding resin. The catalyst is an organo-transition metal compound, organo-tin compound, or a combination thereof.

Catalyzed mica tapes for electrical insulation

The present invention is directed to conductive polymer composition that have positive temperature coefficients, electrical devices comprised thereof and methods of making the same. The composition comprises a thermoset polymer matrix containing discretely distributed thermoplastic material and dispersed conductive material. Preferably, the thermoset and thermoplastic polymers are substantially immiscible and have comparable volume transition temperatures, such as bisphenol A liquid epoxy resins and oxidized polyethylene.

Conductive polymer compositions, electrical devices and methods of making

Liquid crystal thermoset epoxy resin is used as an electrical insulator on electrical conducting devices such as coils and transformers. The linear epoxy/mesogen/epoxy molecule of the liquid crystal thermoset epoxy resin results in a electrical insulator with a high degree of crystallinity. This results in an electrical insulator with mechanical and electrical properties suitable for use in high temperature, high stress environments.

Electrical insulation using liquid crystal thermoset epoxy resins

Materials and methods for the fabrication of high density, low temperature fired microwave ferrites for use in microwave power devices, transmission line elements, isolators, circulators, and phase shifters. Very fine (sub-micron) ferrite powders made by sol-gel methods are mixed with solvents and binders then tape-cast. Ferrite tapes in the unfired state are cut into complex shapes and may be provided with via holes. These ferrite sheets are fired discretely, or are laminated, cofired with printed metal pastes, or other active and passive ceramic tapes.

Process for fabricating a microwave power device

Electrical circuit protection devices containing PTC elements comprised of conductive polymers which exhibit PTC behavior and are used to protect a load in an electrical circuit, in which the PTC conductive polymers are based on highly crystalline and highly ordered liquid crystal polymers and particulate conductive fillers dispersed therein, which are cross-linked by radiation. These circuit protection devices operate as automatically resettable current limiters and are particularly useful for protecting motors, solenoids, telephone lines and batteries, and for enhancing circuit interruption capability when used in conjunction with breakers and contactors. The liquid crystal polymers include aromatic polyesters, e.g., poly(p-phenylene terephthalate) and poly(p-hydroxybenzoate); aromatic copolyesters, e.g., poly(p-hydroxybenzoate-co-2,6-hydroxynaphthoate), poly(deca-methyleneterephthaloyl di-p-hydroxybenzoate, and poly(ethylene terephthalate-co-oxybenzoate); aromatic copolyester amides, e.g., poly(2,6-hydroxy-naphoate-phenoxyaminoterephthoate); aromatic polyamides, e.g., poly(p-phenylene terephthalamide), Kevlar, poly(p-benzamide), poly(2-chloro-1,4-phenylene terephthalamide), poly(p,p'-biphenylamide), and poly(2,6-napthalamide); aromaticpolyazomethines, e.g., poly (nitro-2-methyl-1,4-phenylenenitriloethylidine-1,4-phenylenethylidine), poly(nitrilo-2-methyl-1,4-phenylenenitrilomethylidine-1,4-phenylenemethyli dine), and poly(nitrolo-2-chloro-1,4-phenylenenitrilomethylidine-1,4-phenylenemethyli dine); and, blends thereof. The particulate conductive fillers include carbon black, carbon fibers, graphite, and metal flakes.

Electrical circuit protection devices comprising PTC conductive liquid

A method for precipitating ferrite at room temperature which involves dissolving metal salts in deaerated water, using a base solution to precipitate metal hydroxides, adding an oxidizing agent that has a standard reduction potential greater than 1.229 V versus standard hydrogen electrode. The oxidizing agent further preferably has a standard reduction potential less than 1.8 V versus standard hydrogen electrode. The oxidizing agent is preferably one of hydrogen peroxide, ammonium peroxydisulfate, ozone, nitrous acid, NO, and N.sub.2 O. The base is preferably ammonium hydroxide.

Method for preparation of ferrite powders at room temperature

A resin-rich electrically conductive felt material is described. The described conductive felt can be used to suppress corona discharge in high voltage generator coils. The conductive felt is prepared by treatment with electrically conducting polymers, such as polyaniline and polypyrrole, and resistivity values ranging from 4,000 to 100,000 ohms may be obtained. This treated felt can be readily impregnated with thermoset resins, such as epoxies, to provide flexible prepregs suitable for coil bonding applications in turbine generators.

Electrically conductive prepreg for suppressing corona discharge in high

Novel conductive liquid compositions which have low resistivity when carrying an applied steady-state current (I.sub.Steady-State) but exhibit sharp increases in resistivity when subject to an applied fault current (I.sub.Fault). When used in circuit protection devices, the novel conductive liquid compositions having low resistivity are contained within an elongated flexible tube sealed by electrodes electrically connected to a load of an electrical circuit. The conductive liquid compositions carry an applied normal current under steady-state conditions. The flexible tube is deformed by radial contraction transverse to the direction of current flow and axial expansion, when an excessive current of fault magnitude is sensed by an actuator electrically connected to the electrodes and mechanically connected to the flexible tube to apply a deformation force on the tube, thereby causing the current path of the conductive liquid compositions to have high resistivity in order to limit the let through current to a safe value (I.sub.Limited). When the excessive current is removed, the deformation is correspondingly removed and the conductive liquid composition automatically reverts back to its original low resistivity state. The invention has specific applications as automatically resettable fuses or current limiters.

Conductive liquid compositions and electrical circuit protection devices

The invention provides an electrical circuit protection device using a conductive liquid contained in a flexible tube contacted and sealed at each end by an annular metal electrode capped by a flexible membrane. The flexible tube is further sealed inside a solid insulating tube which contains a ferromagnetic liquid. The ferromagnetic liquid surrounds the flexible tube and remains in intimate contact with the outside of the flexible tube and is connected to a load sensing element which generates a magnetic field in the ferromagnetic fluid in response to excessive currents applied in the current path through the conductive liquid between the electrodes. This assembly is contained inside a tubular resistor. Under normal current conditions, a current flows through the conductive liquid which has relatively low resistivity. Upon a fault condition, a self generated magnetic field from the fault current causes the ferromagnetic fluid to rapidly constrict and pinch off current flow in the conductive liquid by constricting the current path in the liquid through deformation of the flexible capsule, i.e., by radial contraction and axial expansion. The current is then preferably commutated to the cylindrical resistor to limit the let through current to a safe value. Once the fault is limited, the magnetic field is dissipated and the flexible membranes force the conductive liquid and ferromagnetic fluid back to its their original position and the conductive liquid accordingly automatically reverts back to low resistivity for normal current conduction.

Electrical circuit protection devices comprising conductive liquid

An assembly for protecting a conduit having a core and an axial length, which length is susceptible to being pinched by a structure is disclosed. The conduit includes an insulating coating in surrounding relationship about the core, with the assembly including a semiconductive layer in surrounding relationship about the insulating coating, and a switching layer in surrounding relationship about the semiconductive layer. The semiconductive layer being formed from partially vulcanized ethylene propylene rubber including particles of a conductive element in the form of carbon black, silver, nickel, aluminum or the like. The switching layer is non-conductive in its unstressed state and conductive when pinched such that the switching layer completes a current flow path between the semiconductive layer and either a grounded structure or another conductive layer, which condition may then be detected.

Assembly for detecting and locating cable pinching

Surfactants in an aqueous solution is recovered from polychlorinated biphenyls and other aromatic organic compounds contaminating the solution. An electrical current is passed through a surfactant-containing aqueous solution contaminated with a colloidal dispersion of organic compounds at a voltage sufficient to electrochemically breakup the dispersion without polymerizing the surfactant. The contaminating aromatic organic compounds are then separated from the surfactant-containing aqueous solution. The separated surfactant-containing aqueous solution may be recirculated to a waste treatment process for cleaning additional organic compounds from contaminated equipment.

Growing community of inventors

Pittsburgh, PA, United States of America

Karl F Schoch, Jr