Conductive Patents (Class 336/84C)
  • Patent number: 4862316
    Abstract: A housing for the magnetic induction coils of the search loop assembly of a metal detector is constructed of plastic resin reinforced with non-metallic electrically conductive graphite fibers, and is connected to ground potential of the main electronics package of the metal detector so that the housing acts as a static-draining shield for the search loop assembly. The mixture of graphite fibers and plastic conducts electricity well enough to prevent accumulation of static electricity charges and makes the housing stronger and more abrasion resistant than similar housings of non-reinforced plastic. The housing may be molded as two halves to include a central aperture, to allow the user of the metal detector to see the precise location on the ground at which to dig for detected targets.
    Type: Grant
    Filed: February 29, 1988
    Date of Patent: August 29, 1989
    Assignee: White's Electronics, Inc.
    Inventors: Peter T. Smith, Mark W. Rohde, Donald K. Shoemaker
  • Patent number: 4853665
    Abstract: A transformer apparatus which includes a core and first and second coils which are each magnetically coupled to the core. Each coil is generally cylindrical and have a circumferential surface and first and second axial extremities. Shielding is disposed around at least the first coil comprising a web shaped metallic, non-magnetic, electrically conductive generally rectangular member. The member has a first portion extending around substantially the entire circumferential extent of at least one coil and the member further includes second and third portions extending respectively about a substantial portion of each of the first and second axial extremities.
    Type: Grant
    Filed: October 28, 1988
    Date of Patent: August 1, 1989
    Assignee: General Signal Corporation
    Inventor: John Olesak
  • Patent number: 4847583
    Abstract: The invention provides a toroidal transformer with integrated self inductance device, comprising a closed main annular magnetic circuit on which an inner electric winding is coiled. A magnetic core, in the form of an open annular sector, is held in position at the periphery of the inner winding by peripheral bars. The assembly is covered by the outer electric winding. The magnetic core determines the value of the self inductance of the transformer.
    Type: Grant
    Filed: June 24, 1988
    Date of Patent: July 11, 1989
    Assignee: Societe Pour L'Application de L'Optique et de L'Electronique a La Recherche et a L'Automatisation Optelec, societe anonyme
    Inventor: Chappel Bernard
  • Patent number: 4845453
    Abstract: A high-voltage voltage transformer with a core at high voltage which is surrounded coaxially by a high voltage winding provided with a slotted metal shield and with a low voltage winding also coaxially surrounding the same, as well as with a coaxial shielding electrode at ground potential and surrounding the high and low voltage winding is to be so constructed that coupling effects of high potentials for high frequency transient switching operations onto the secondary side, above all the secondary lead-out connecting lines cannot occur to any disturbing extent. This is achieved in that spaced at a slight distance up to a maximum of about 5 mm. from the metal shield a discharge electrode concentrically surrounding the same is provided insulated with respect to the metal shield. The discharge electrode is electrically conductively connected by way of one or several connecting lines of low inductance with the shielding electrode.
    Type: Grant
    Filed: November 7, 1988
    Date of Patent: July 4, 1989
    Assignee: MWB Messwandler-Bau AG
    Inventors: Norbert Preissinger, Hermann Eberlein
  • Patent number: 4833773
    Abstract: A coil assembly for a metal detector and a method for making the coil assemblies for metal detectors of the type used for detecting metal fragments in foodstuffs and pharmaceuticals, the method comprising providing a frame of non-metallic material, the frame have an aperture therethrough for the passage of material undergoing inspection, winding coils of electrically conductive strands on the frame, applying plastic in liquid form to the frame and coils, less the aperture portion of the frame, and applying metal in fluid form to the plastic to encase the plastic in a metal layer.
    Type: Grant
    Filed: June 1, 1987
    Date of Patent: May 30, 1989
    Assignee: Barkley & Dexter Laboratories, Inc.
    Inventor: James M. Moran
  • Patent number: 4814734
    Abstract: A coil assembly for a metal detector of the type used for detecting metal fragments in foodstuffs and pharmaceuticals, the assembly comprising a frame of non-metallic material, the frame have an aperture therethrough for the passage of material undergoing inspection, a coating of carbon material applied to the exterior of the frame, a layer of plastic material applied over the carbon material, electrically conductive strands wound over the plastic material, the frame being fixed to a rigid metal housing providing an enclosed void around the exterior of the coated frame and strands, and foam plastic enveloping the frame and strands, the void being filled with the foam plastic.
    Type: Grant
    Filed: June 14, 1988
    Date of Patent: March 21, 1989
    Assignee: Barkley & Dexter Laboratories, Inc.
    Inventor: James M. Moran
  • Patent number: 4808929
    Abstract: A shielded solenoid for use in well logging is disclosed in which a cylindrical or solenoidal coil is provided in a support member. A shield is spirally wrapped about the wall of the support member and the coil. The resulting toroidally shaped shield has its individual turns cut so that no complete electrical path exists in each loop of the shield. Each loop of the coil is electrically connected to a ground ring. The shielded solenoid is capacitively shielded from the borehole environment. The shielding is effective because the shielding conductors are effectively transparent to TE electromagnetic fields generated by alternating current flow in the cylindrical coil and substantially eliminate TM electromagnetic fields generation by such current flow.This abstract of the disclosure is neither intended to define the scope of the invention, which is measured by the claims, nor is it intended to limit the invention in any way.
    Type: Grant
    Filed: May 19, 1987
    Date of Patent: February 28, 1989
    Assignee: Schlumberger Technology Corporation
    Inventor: Richard W. Oldigs
  • Patent number: 4806896
    Abstract: An electromagnetic shield for electromagnetic apparatus comprises a plurality of shield coils (2-7) wound intermittently on a looped magnetic core (11). Same polarity terminals of the shield coils are connected to form current paths which prevent external fluxes .phi..sub.1, .phi..sub.2 from entering into the core.
    Type: Grant
    Filed: July 13, 1988
    Date of Patent: February 21, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoshirou Shikano, Shinichirou Hayashi
  • Patent number: 4794338
    Abstract: Self-shielded gradient coils are used to eliminate interactions between gradient coils and external structure. Interactions between gradient coils for different gradient axes are controlled by means of a balanced interconnection within each separate gradient coil set. One or both of the inner and outer coils within a gradient coil set are split such that for any localized capacitive current flow between coil sets there will be an equal and opposite current flow somewhere else between the coil sets.
    Type: Grant
    Filed: November 25, 1987
    Date of Patent: December 27, 1988
    Assignee: General Electric Company
    Inventors: Peter B. Roemer, Kenneth M. Bradshaw
  • Patent number: 4757295
    Abstract: A pulsed transformer capable of providing up to 500 kilovolt or higher, 10 nanosecond rise time, and 1000 joule or higher pulses comprising non-conducting or insulated transformer cores each separated by conductive grading rings wherein n coaxial cables in combination with the grading rings are connected in parallel at one end and in series at their other ends. The transformer may function as either an inverting or non-inverting transformer. In a transformer with n cables, if a pulse voltage of V is applied to the input, an output voltage of nV will appear at the output. The cores function to isolate the coxial cables and permit them to be connected in series at their one end. Weight may be minimized by operating the transformer in gaseous Freon rather than transformer oil.
    Type: Grant
    Filed: September 16, 1987
    Date of Patent: July 12, 1988
    Assignee: Avco Research Laboratory, Inc.
    Inventor: Charles T. Pike
  • Patent number: 4755783
    Abstract: Inductive devices, i.e., transformers, coils, inductors, etc. are produced from a rolled flexible circuit. The flexible circuit is comprised of a dielectric substrate having a circuit pattern thereon. The circuit pattern is configured such that, upon rolling, one or more coils is formed thereby defining an inductor, transformer, etc. Additionally, these inductive devices may be easily shielded using a ground plane in the flexible circuit. The rolled flexible circuit may be secured in several ways including an adhesive or by using a thermoplastic bonding layer which acts to heat seal the circuit together. The inductive devices of the present invention may be wrapped or rolled about a permeable core which improves inductance. Inductor devices manufactured in accordance with the present invention have the advantages of being small, surface mountable, inexpensive to manufacture and being capable of insertion onto printed wiring boards using automated insertion equipment.
    Type: Grant
    Filed: November 18, 1986
    Date of Patent: July 5, 1988
    Assignee: Rogers Corporation
    Inventors: Cathy Fleischer, William Harper, Joseph E. Johnston, Scott Simpson, Richard T. Traskos
  • Patent number: 4748430
    Abstract: The transformer comprises a primary coil comprising a conductive strip wound around an insulating coil base comprising a central part, two parts located at the ends of the central part with a roughly rectangular shape, the bigger sides of which extend along a second and a third direction which are mutually opposite. The length of the central part, measured along the initial direction, is determined so that the two ends have the directions of their bigger sides colinear in pairs when the central part is wound around the coil base. The two angles, formed at the points where the edges of the parts located at the ends intersect the edges adjacent to the bigger sides of the central part, are truncated to prevent the overlapping of the two ends when the central part is wound around the coil base.
    Type: Grant
    Filed: November 17, 1986
    Date of Patent: May 31, 1988
    Assignee: Thomson-CGR
    Inventor: Noel Guais
  • Patent number: 4739272
    Abstract: A wall-engaging apparatus for microinductively investigating a characteristic of an earth formation traversed by a borehole comprises an antenna set mounted in an longitudinally elongated body adapted for a sliding engagement with the wall of the borehole. The antenna set includes a transmitter antenna mounted in the body for coupling electromagnetic energy into a formation; a receiver antenna for sensing a signal indicative of the characteristic; and at least one electroquasistatic shield element mounted coaxially with the magnetic dipole axis of the transmitter antenna.
    Type: Grant
    Filed: May 31, 1984
    Date of Patent: April 19, 1988
    Assignee: Schlumberger Technology Corporation
    Inventors: Douglas D. Griffin, Weng C. Chew, Brian Clark, Robert L. Kleinberg
  • Patent number: 4731599
    Abstract: A combined high voltage current and voltage transformer of head-type construction with a column of insulating material carrying the top housing whereby the active parts of the current transformer and above the same the active parts of the voltage transformer are arranged within the top housing. A simple manufacture of the top housing and a good seal with as few as possible lead-outs to be sealed off inside of the top housing is made possible by the construction of this invention. At the same time, the primary conductor of the current transformer as also the secondary system of the current transformer and the active parts of the voltage transformer are to be assemblable in a simple manner. This is achieved in that the primary conductor of the current transformer is constructed U-shaped whose base extends at least approximately concentrically through the ring of the secondary system of the current transformer.
    Type: Grant
    Filed: March 11, 1987
    Date of Patent: March 15, 1988
    Assignee: MWB Messwandler-Bau AG
    Inventor: Norbert Preissinger
  • Patent number: 4727316
    Abstract: A transformer current sensor having primary turns carrying a primary current for a superconducting coil and secondary turns only partially arranged within the primary turns. The secondary turns include an active winding disposed within the primary turns and a dummy winding which is not disposed in the primary turns and so does not experience a magnetic field due to a flow of current in the primary turns. The active and dummy windings are wound in opposite directions or connected in series-bucking relationship, and are exposed to the same ambient magnetic field. Voltages which might otherwise develop in the active and dummy windings due to ambient magnetic fields thus cancel out. The resultant voltage is purely indicative of the rate of change of current flowing in the primary turns.
    Type: Grant
    Filed: April 16, 1985
    Date of Patent: February 23, 1988
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Stewart S. Shen, C. Thomas Wilson
  • Patent number: 4725804
    Abstract: An electrostatic fork shield for a layer wound transformer yielding a high degree of noise attenuation. A three phase transformer has three leg portions which are interconnected at both ends by a yoke. Around each leg portion is wound layers of primary coil and secondary coil. The transformer core, coils and shields lie within an enclosure. Both the inner wall and outer wall of each transformer coil is covered with a non-ferrous conductive shield. Between the primary and secondary coils of each phase and their respective vertical shields, is interposed a glastic spacer. A horizontal shield lies across each end of the transformer coil. The horizontal shield comprises a base and inner and outer fingers which cover a large portion of the surface of the coil ends but do not form a complete electric path around any leg portion. Two barrier shields are located on one side of the transformer between adjacent phases and are connected to the inner fingers of each horizontal shield.
    Type: Grant
    Filed: July 3, 1986
    Date of Patent: February 16, 1988
    Assignee: Square D Company
    Inventor: Hassan Yarpezeshkan
  • Patent number: 4714880
    Abstract: This detector comprises at least one bar of a ferromagnetic material about which are wound several turns of a conductive coaxial cable cut in its center into first and second portions, said portions being connected in such a way that the sheath or tube of the first portion is connected to the core of the second portion and the sheath or tube of the second portion is connected to the core of the first portion, each of the two free cable ends being used for measuring the output voltage of the detector.
    Type: Grant
    Filed: June 5, 1986
    Date of Patent: December 22, 1987
    Assignee: Commissariat a l'Energie Atomiques
    Inventor: Paul Charmet
  • Patent number: 4709205
    Abstract: An inductive current measuring sensor is provided comprising several coils connected electrically in series and disposed in a polygonal contour, so as to surround the conductor on which it is desired to measure the current. Each coil comprises windings disposed on an insulating bobbin and connection elements. The bobbins are disposed on the face of a printed circuit having a central recess through which the conductor may pass. The printed circuit carries conducting tracks interconnecting the fixing points of the connection elements together and to external connection members.
    Type: Grant
    Filed: June 24, 1986
    Date of Patent: November 24, 1987
    Assignee: La Telemecanique Electrique
    Inventors: Gilles Baurand, Rene Fouret, Marek Rundsztuk
  • Patent number: 4698473
    Abstract: An improved induction coil of a type used in heat treating metal workpieces comprises a protective lining bonded to a copper coil, which lining is formed preferably of a substantially molybdenum alloy.
    Type: Grant
    Filed: May 2, 1986
    Date of Patent: October 6, 1987
    Assignee: General Motors Corporation
    Inventors: William V. Alcini, Steven L. Avery
  • Patent number: 4678699
    Abstract: A stampable thermoplastic composite having at least one thermoplastic layer and at least one shielding layer. The shielding layer comprises a material having an elongation to break of at least 8 percent, and the composite having an EMI/RFI shielding effectiveness of at least 30 db.
    Type: Grant
    Filed: January 11, 1985
    Date of Patent: July 7, 1987
    Assignee: Allied Corporation
    Inventors: Gina R. Kritchevsky, John A. Gregor, Manfred W. Gruendig, Gregory J. Sellers, Barbara Liss
  • Patent number: 4673879
    Abstract: Method and apparatus for scanning a generally cylindrical workpiece for flaws. A cylindrical metallic sleeve is rotatably supported about a workpiece path of travel. Two differentially wound energization coils surround the sleeve near two apertures in the sleeve. The coils are energized with a high frequency signal that induces eddy currents in the workpiece. The apertures periodically disrupt the eddy current inducing magnetic fields and enhances signals from the coils indicative of the presence of flaws in the workpiece.
    Type: Grant
    Filed: June 27, 1984
    Date of Patent: June 16, 1987
    Assignee: Rupublic Steel Corporation
    Inventors: Richard M. Harris, David A. Valek, James M. Toth, Richard F. Abramczyk
  • Patent number: 4663603
    Abstract: A winding system for gas-cooled transformers, comprising windings disposed around a core; and at least one insulation torus, consisting of an insulating mass, said torus having embedded therein electrodes electrically connected to an adjoining winding for suppression of the electric field intensity between sinding and electrodes. The winding connected to the electrodes is divided into separate winding sections across the height of the winding, and each of these sections is connected to one electrode.
    Type: Grant
    Filed: December 12, 1985
    Date of Patent: May 5, 1987
    Assignee: Holec Systemen en Componenten B.V.
    Inventors: Gerardus A. van Riemsdijk, Fredericus F. M. Muller
  • Patent number: 4660014
    Abstract: An isolation transformer for connection between a source of alternating current power and electrical components, the operation of which components is affected by voltage excursions occasioned by electromagnetic pulses. The transformer includes a ferromagnetic core including first and second ends and at least two legs extending between the ends and defining therewith at least one window in the core. Also included are a primary coil surrounding a first portion of the core and extending through a window in the core, and a secondary coil, spaced from the primary, surrounding a second portion of the core and extending through a window in the core. A metallic isolation shield is positioned between the coils with the shield having core apertures for receiving components of the core so that the shield passes through each window of the core. A first metallic housing is mounted on the shield and has an opening for receiving the primary coil and the portion of the core on the primary coil side of the shield.
    Type: Grant
    Filed: June 19, 1985
    Date of Patent: April 21, 1987
    Assignee: Jaycor
    Inventors: Eric P. Wenaas, Ralph M. Wheeler
  • Patent number: 4652846
    Abstract: A transformer of small installed volume which affords, besides electrical separation, also an effective static protective shield between the power supply side and the user side, along with simple production and assembly. To accomplish this, a two-chamber transformer with a coil form for the primary winding and a coil form for the secondary winding, both plugged one behind the other onto the transformer core in the direction of the coil axes and a stamped metal foil frame as the shielding wall between the adjacent face flanges of the coil forms are used. The transformer is particularly well suited for application in equipment of the entertainment, communications and medical technologies.
    Type: Grant
    Filed: February 19, 1986
    Date of Patent: March 24, 1987
    Assignee: Siemens Aktiengesellschaft
    Inventor: Ulrich Sobottka
  • Patent number: 4622192
    Abstract: A method for preparing stampable composites of polymer of olefin and fiber mat composites which are a mixture of glass fiber and carbon fiber by surrounding a fiber mat of a mixture of glass fiber and carbon fiber with a matrix of polymer of olefin. A stampable composite of polymer of olefin and fiber mat produced by such a method.
    Type: Grant
    Filed: January 10, 1984
    Date of Patent: November 11, 1986
    Assignee: Phillips Petroleum Company
    Inventor: Chen-Chi M. Ma
  • Patent number: 4616176
    Abstract: The current transducer is of the type comprising a Rogowski coil extending around a first conducting element in which a current to be detected flows. The first conducting element is provided at one end with a first terminal connector. A second conducting element is mounted on the first one so as to cover and preferably embed the external periphery of the coil. The second conducting element is electrically connected to the first conducting element at the end thereof which is opposite to the one end provided with the first terminal connector. A second terminal connector is provided on the second conducting element on the same side of the plane of the coil as the first terminal connector. This arrangement forces the current flowing between the first and second terminal connectors via the first and second conducting elements to flow around the periphery of the coil and thus to shield the coil.
    Type: Grant
    Filed: January 12, 1984
    Date of Patent: October 7, 1986
    Assignee: Hydro Quebec
    Inventors: Hubert P. Mercure, Michel G. Drouet
  • Patent number: 4608534
    Abstract: Eddy current probes which are used to internally or externally inspect cylindrical components for localized defects have a main coil arrangement that induces and senses eddy current in the components. In accordance with the present invention, the probe further includes an element associated with the main coil arrangement to generate a detected defect signal distinct from a detected noise signal. The element can include one or more further coils mounted coaxially with the main coil arrangement so as to be between the main coil arrangement and the component to be inspected. The element may alternately be a cylindrical conductive sleeve mounted coaxially with the main coil arrangement so as to partially shield the coil arrangement from the component to be inspected. An electrical phase shifting network may be connected to the one or more further coils to enhance the distinction between the signals.
    Type: Grant
    Filed: June 16, 1983
    Date of Patent: August 26, 1986
    Assignee: Canadian Patents & Development Limited
    Inventors: Valentino Cecco, Hugh W. Ghent
  • Patent number: 4605899
    Abstract: The sensor makes it possible to increase the performances, particularly from the sensitivity and frequency band standpoints, by means of a coaxial helical coil, matched to the connecting end to an auxiliary current measuring apparatus. At each turn, a portion of the external conductor is bared and equipped with elements for matching to the characteristic impedance in order to compensate the breaks caused in this way.
    Type: Grant
    Filed: October 11, 1983
    Date of Patent: August 12, 1986
    Assignee: Thomson CSF
    Inventors: Gregoire Eumurian, Jean-Pol Levan
  • Patent number: 4591941
    Abstract: A double insulating protected system for use in coupling an instrumentation system to a remote power source so as to test an experimental system without posing life-threatening hazards. Connection between the instrumentation system and power source is accomplished by a pair of cascaded isolating transformers, with the connections between the two transformers being inaccessable, such as by a separate housing. The instrumentation system equipment ground is coupled to the experimental system equipment ground via a drain conductor so as to reference the former system to the same potential as that of the latter. The system provides a double insulation system such that a primary-to-secondary, primary-to-frame, or secondary-to-frame fault occurring in either of the transformers, or similar faults in the instrumentation system, will not result in a life-threatening situation to the system user.
    Type: Grant
    Filed: September 21, 1983
    Date of Patent: May 27, 1986
    Assignee: EG&G Washington Analytical Services Center Inc.
    Inventors: Michael E. Gruchalla, David C. Koller
  • Patent number: 4586015
    Abstract: A transformer having a molded coil which can stably sustain an electric-shock free function for a long period of time. The transformer has a grounded conductive shield layer on the surface of the molded coil. The shield layer is composed of a plurality of segments so that a stable bonding of the shield layer to resin is kept for a long period of time, with the respective segments being grounded by a conductor.
    Type: Grant
    Filed: June 20, 1983
    Date of Patent: April 29, 1986
    Assignee: Hitachi, Ltd.
    Inventors: Yasuyuki Takahara, Hirofumi Kubo, Shigeo Hosaka, Tomomi Izuna, Toshiyuki Fujimori
  • Patent number: 4558406
    Abstract: A transformer arrangement for generating rectified, high voltages has a primary winding wound around the transformer core and is surrounded by a metallic shield. A mass of insulation material, including an insulation layer, surrounds the metallic shield. A secondary winding is embedded in the mass of insulation material outside the insulation layer. The secondary winding has an end terminal carrying a high alternating voltage potential and presents an outer circumference. A heat conducting metal band rests on and covers a major portion of the outer circumference of the secondary winding but does not constitute a short-circuit winding for the transformer. The terminal end of the secondary winding is connected electrically and thermally with a plurality of rectifiers via the metal band.
    Type: Grant
    Filed: October 11, 1983
    Date of Patent: December 10, 1985
    Assignee: ANT Nachrichtentechnik GmbH
    Inventors: Klaus H. Geissler, Herbert Bock
  • Patent number: 4540967
    Abstract: This invention relates to a molded transformer whose windings are cast-insulated with a cast resin, and consists in disposing an electrically conductive layer within the resin insulation of the winding and grounding the conductive layer, thereby to enhance a withstand voltage with the dimensions of the air gap between the windings reduced and with a winding supporting spacer omitted.
    Type: Grant
    Filed: June 28, 1982
    Date of Patent: September 10, 1985
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Takashi Chitose
  • Patent number: 4531109
    Abstract: A tuning coil assembly includes an adjustable coil wound on a bobbin around which is placed a plastic coil support sleeve. The sleeve provides protection for the coil and aids in adjustment of a tuning slug inside the coil by an automatic alignment fixture. The plastic coil support sleeve is coated with a thin metallic layer or alternately impregnated with metallic particles to provide electromagnetic radiation shielding for the coil. The combination of the sleeve for both coil adjustment and electrical shielding permits placement of the coil assembly on a smaller area of a circuit board than would be possible with a separate metal shield can.
    Type: Grant
    Filed: March 28, 1983
    Date of Patent: July 23, 1985
    Assignee: RCA Corporation
    Inventor: Perry C. Olsen
  • Patent number: 4518941
    Abstract: A pulse transformer for use in a switching power supply having primary and secondary windings wound concentrically around a common core and two electrostatic shield foils interposed between the primary and secondary windings with an insulator disposed between the electrostatic shield foils.
    Type: Grant
    Filed: November 16, 1983
    Date of Patent: May 21, 1985
    Assignee: Nihon Kohden Corporation
    Inventor: Hajime Harada
  • Patent number: 4514693
    Abstract: Transmitting and receiving coils for radio frequency (RF) dielectric well logging are shielded in copper enclosures to substantially remove unwanted electrostatic or capacitive signals introduced by the conductive fluids in the well bore.
    Type: Grant
    Filed: October 17, 1979
    Date of Patent: April 30, 1985
    Assignee: Texaco Inc.
    Inventor: Richard A. Meador
  • Patent number: 4510476
    Abstract: A high voltage isolation transformer (10) is provided with primary (30) and secondary (32) coils separated by discrete electrostatic shields from the surfaces of insulating spools (12,14) on which the coils are wound. The electrostatic shields are formed by coatings (49,59,50,60) of a compound having a low electrical conductivity which completely encase the coils and adhere to the surfaces of the insulating spools (12,14) adjacent to the coils. Coatings (47,48) of the compound also line axial bores of the spools, thereby forming electrostatic shields separating the spools from legs (18,20) of a ferromagnetic core (16) extending through the bores. The transformer is able to isolate a high constant potential applied to one of its coils, without the occurrence of sparking or corona, by coupling the coatings lining the axial bores to the ferromagnetic core and by coupling one terminal of each coil to the respective coating encasing the coil.
    Type: Grant
    Filed: June 21, 1983
    Date of Patent: April 9, 1985
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Carroll H. Clatterbuck, Arthur P. Ruitberg
  • Patent number: 4507636
    Abstract: The present invention relates to a structure of neutral point of multiphase transformers for large secondary currents. Such multiple phase transformers, usually three phase transformers, are used for example for the operations of arc furnaces, and the secondary current of the transformer may amount to several thousand ampere. The neutral point is made as a plate (24) of material with good electric conductivity and is located within the transformer tank (27). Between the neutral point plate (24) and the tank wall (27) there is located a plate (25) of a material with good conductivity and serving as a screen for reducing losses in the tank wall (screen plate). The transformer is star connected on the secondary side. Each phase of the secondary winding consists of several windings connected in parallel, and the tappings are passed as parallel conductors onto the neutral point plate (24).
    Type: Grant
    Filed: February 23, 1984
    Date of Patent: March 26, 1985
    Assignee: National Industri A/S
    Inventors: Odd J. Eilertsen, Ottar H. Svensen
  • Patent number: 4504812
    Abstract: An improved transformer (20) and method of transformer construction. Primary and secondary windings (30 and 32) are spirally wound onto a spherically shaped core member (24). The core is preferably of laminated construction and can be of either planar or radial configuration. A flux intensifier shield member (40) defines an inner spherical cavity (Y) sized to cooperatively overlie and substantially enclose the inner core and winding assembly. The shield may comprise a pair of hemispherically shaped members including radially extending leaf-like vanes (46) that enable and enhance cooling of the core assembly as well as providing improved transformer efficiency and protective shielding of the core assembly.
    Type: Grant
    Filed: June 7, 1983
    Date of Patent: March 12, 1985
    Inventors: Donald I. Moermond, deceased, Dennis L. Moermond, personal representative, Raymond A. Moermond, personal representative
  • Patent number: 4496924
    Abstract: A pulse transformer is used in a radar transmitter to transform a high current pulse at relatively low voltage into a very high voltage pulse which can be used to directly drive a magnetron oscillator. The potential of the output pulse can be of the order of 30 kV and since the transformer is required to operate at very high peak powers of the order of two megawatts, it must be very carefully designed to avoid excessive electrical losses and voltage breakdown. The core material of the transformer consists of a closely wound reel of magnetic material in the form of an elongate tape, which is mechanically fragile. The magnetic core is loosely mounted within a sealed container so that the primary and secondary windings surround it. A conductive shield is placed around the magnetic material so as to protect it from the very large electric fields generated within the transformer. This prevents the ionization of gases which could lead to the rapid deterioration of the magnetic core material.
    Type: Grant
    Filed: July 27, 1982
    Date of Patent: January 29, 1985
    Assignee: The Marconi Company Limited
    Inventor: Robert Richardson
  • Patent number: 4484171
    Abstract: A shielded transformer of the type particularly used as an isolation transformer, has a greatly reduced interwinding capacitance. Metallic overlap is provided, completely across a juncture of the metallic shield with faces of the windows in the core, and completely across a juncture of the metallic shield with the metallic case. This metallic overlap is tolerant to misalignments and variations in fit, completely eliminating gaps that cannot be economically made small with the butt joint of present art. The overlap comprises grooves in faces of the window or in the case. In a second embodiment, the overlap comprises grooves in channels on faces of the window and on the case. The shield fits into the grooves.
    Type: Grant
    Filed: February 18, 1983
    Date of Patent: November 20, 1984
    Inventor: Robert C. McLoughlin
  • Patent number: 4471333
    Abstract: A current transformer having at least one ring-shaped core with a secondary winding mounted thereon, and a primary conductor, located within its casing. An inner tube is provided between the ring-shaped core and the primary conductor, one end of the tube being electrically connected to the casing and its other parts electrically insulated therefrom. A cylindrical, electrically conductive screening shield at least partially overlaps the inner tube and is electrically connected to the casing on the side of the ring-shaped core which is distal from the electrical connection between the casing and the inner tube, while the other parts of the shield are electrically insulated from the casing. This overlap forms a short-circuit loop for any steep progressing wave which is generated when switching on a potential-free part of the circuitry, or when due to an interruption, a small capacitive current breaks off.
    Type: Grant
    Filed: February 22, 1982
    Date of Patent: September 11, 1984
    Assignee: Sprecher & Schuh AG
    Inventor: Viktor H. Stephanides
  • Patent number: 4464544
    Abstract: A corona effect sound emitter including a discharge electrode producing corona discharge and surrounded by a spherical counter electrode is partially inserted in a housing which encloses a high frequency generator, modulation transformer and a power supply transformer of which the power supply transformer supplies the discharge electrode with electric current. A thin plate of a magnetic metal transversally extends in the housing so that secondary windings of the transformers are positioned above the plate and are separated from the primary windings of the transformers disposed below the plate.
    Type: Grant
    Filed: July 23, 1982
    Date of Patent: August 7, 1984
    Inventor: Siegfried Klein
  • Patent number: 4460884
    Abstract: A transformer including a lamination core of band iron and a magnetic screen which consists of a wound iron band arranged around the lamination core (5) and which is secured to the core by means of expansion wedges provided in the space between the core and the screen 13. The expansion wedges (7) extend transversely of or at an angle with respect to the winding direction of the wound iron band.
    Type: Grant
    Filed: June 25, 1982
    Date of Patent: July 17, 1984
    Assignee: U.S. Philips Corporation
    Inventors: Sieghard Post, Siegfried Mehl
  • Patent number: 4459575
    Abstract: In a high power density transformer composed of a core and a coil assembly unit (or two such units), with the coil assembly unit including a primary winding, a secondary winding, a coil carrier supporting the windings, an insulating system, and a metal shield between the primary and secondary windings which is in electrically and thermally conductive connection with a metal grounding structure so that the metal grounding structure constitutes a support for the coil assembly, the metal shield serves as the coil carrier which is disposed directly on the metal grounding structure.
    Type: Grant
    Filed: January 8, 1982
    Date of Patent: July 10, 1984
    Assignee: LICENTIA Patent-Verwaltungs-GmbH
    Inventors: Klaus H. Geissler, Herbert Bock
  • Patent number: 4459576
    Abstract: A toroidal transformer is provided with an inner winding electrostatic shield formed by bringing together two conductive annular cups having a generally U-shaped radial cross section. The widths and radii of the sidewalls of these cups are dimensioned such that one of the sidewalls of the first cup forms a conductive interference fit with the corresponding sidewall of the second cup, while the other sidewall of the first cup is separated from the corresponding sidewall of the second cup by a gap, which prevents the shield from becoming a shorted turn. The shield formed by these two cups is placed around a wound core and a second winding is wound over the shield to form a transformer.
    Type: Grant
    Filed: September 29, 1982
    Date of Patent: July 10, 1984
    Assignee: Westinghouse Electric Corp.
    Inventors: David A. Fox, Donal E. Baker
  • Patent number: 4451812
    Abstract: An electrostatic shield for an electrical conductor element comprises a sheet-like array of closely spaced elongate electrical conductors interconnected at one end of the array by an end conductor for connection to a common or ground potential. The conductor to be shielded may be in the form of a loop or coil printed on one face of an insulating plate and the array of shielding conductors and the end conductor may be printed on the other face of the insulating plate. The shield may include two or more series of parallel conductors arranged in adjacent banks and each provided with a separate end connecting conductor.
    Type: Grant
    Filed: April 27, 1982
    Date of Patent: May 29, 1984
    Assignee: Sphere Investments Limited
    Inventors: Valentino F. Vescovi, Arthur W. Richards
  • Patent number: 4449111
    Abstract: A transformer has an insulator interposed between respective primary and secondary coils wound on a coil bobbin which has an axial winding part and opposing radially extending flanges. The insulator is made from a continuous sheet of material which is corrugated to provide an insulating base having a width larger than the width of the winding part of the coil bobbin and from a continuous, plastic insulating sheet member having substantially the same width as the winding part. The corrugated insulated base material and insulating sheet member are wound between the primary coil and the secondary coil and the corrugated insulating base is bent at both side edges to be L-shaped to intimately fit to the inner surface of the flanges of the coil bobbin so as to provide an insulator which positively prevents coil wire at each end portion of the coil from dropping out of alignment with respective coil turns.
    Type: Grant
    Filed: February 16, 1982
    Date of Patent: May 15, 1984
    Assignee: Tamura Seisakusho Co., Ltd.
    Inventor: Tomoo Nakajima
  • Patent number: 4430520
    Abstract: A shielding enclosure for a magnetic flux producing device comprises inner and outer casings with closely fitting side walls. One or more leads extending from within the enclosure are laid down during assembly in a clearance slot or groove formed between the casing side walls, and thereafter threaded back out of the clearance slot or groove and extended through a closed aperture in the outer casing for terminal attachment.
    Type: Grant
    Filed: April 7, 1982
    Date of Patent: February 7, 1984
    Assignee: Tibbetts Industries, Inc.
    Inventors: George C. Tibbetts, Joseph A. Sawyer
  • Patent number: 4379999
    Abstract: An electrostatic shield for an electrical transformer comprises a substantially ring-shaped inner insulator of asymmetric vertical cross-section with a side confronting a coil of the transformer being substantially planar and the remaining surface being of a curved section, a field concentration relaxation conductor formed from a conductive foil, completely surrounding the inner insulator, and a multiple outer insulator comprising at least one layer of polyethylene terephthalate (PET) film and at least one mica insulation layer with mica bonded to a non-conductive backing film such as glass tape or PET film by a bonding agent such as epoxy resin, whereby the dielectric strength of the electrostatic shield and hence the transformer, is substantially improved.
    Type: Grant
    Filed: October 30, 1981
    Date of Patent: April 12, 1983
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Minoru Kimura, Teruo Ina
  • Patent number: 4375627
    Abstract: An electric transformer characterized by a transformer tank having an opening with a conducting closure panel in the opening and electrically insulated from the tank, a plurality of first and second conductors of opposite polarities leading from the transformer coil-core assembly with the conductors of opposite polarity comprising forward and return paths. A conducting tubular structure mounted on and extending inwardly from the inside surface of the panel and the return path conductors being connected to the corresponding tubular structures while the forward path conductors extend through the tubular structure and the panel to an external source.
    Type: Grant
    Filed: June 26, 1981
    Date of Patent: March 1, 1983
    Assignee: Westinghouse Electric Corp.
    Inventors: Irvin L. Hansen, Randall W. Haack