Contact Structure Patents (Class 218/48)
  • Patent number: 10991529
    Abstract: An object is to enhance direct-current insulating performance of a gas-blast circuit breaker. The gas-blast circuit breaker includes: a pair of main contacts disposed in a gas tank to face each other and configured to operate for opening and closing a circuit; a pair of arc contacts disposed to face each other and configured to operate for opening and closing the circuit, the arc contacts being disposed coaxially with the main contacts at locations close to the centers of the main contacts, respectively; and an elastic electrically conductive material disposed on an outer surface of an insulating nozzle facing an inner surface of one of the main contacts.
    Type: Grant
    Filed: August 3, 2018
    Date of Patent: April 27, 2021
    Assignee: Hitachi, Ltd.
    Inventors: Hideyuki Kotsuji, Jun Nukaga, Makoto Hirose, Takahiro Nishimura
  • Patent number: 9524837
    Abstract: An electrical contact configuration includes a first contact piece with a contact socket and a second contact piece which can move relative to the first contact piece. The second contact piece has a complementary shape to the first contact piece. An auxiliary contact piece is guided in such a way that it can move in the contact socket of the first contact piece. The auxiliary contact piece is guided in an electrically isolated manner.
    Type: Grant
    Filed: November 15, 2011
    Date of Patent: December 20, 2016
    Assignee: SIEMENS AKTIENGESELLSCHAFT
    Inventors: Sascha Froebel, Rene Guenther
  • Patent number: 9165726
    Abstract: A tap changer for uninterrupted switching over between winding taps of a tapped transformer has two load branches each for a respective phase to be switched. Each load branch has a vacuum switching contact acting as main contact and parallel thereto at least one series connection of a switch-over resistance and a respective further vacuum switching contact. The two load branches are connected with a common load shunt or connectable by mechanical switching elements. Two respective vacuum switching contacts of each load branch are constructionally combined to form a single vacuum switching tube with two separate movable contacts actuatable independently of one another and a common fixed contact. The common fixed contact is connected with the common load shunt or connectable mechanical switching contacts.
    Type: Grant
    Filed: September 2, 2011
    Date of Patent: October 20, 2015
    Assignee: MASCHINENFABRIK REINHAUSEN GMBH
    Inventors: Dieter Dohnal, Klaus Hoepfl, Christian Pircher, Silke Wrede
  • Patent number: 8502101
    Abstract: An exemplary high voltage circuit breaker includes an interruption chamber that is filled with an extinguishing agent. The interruption chamber having at least two separable arcing contact pieces that are coaxially arranged and an arcing zone in which an electric arc is producible during an interruption process. The interruption chamber includes at least two inlets and at least one outlet located in between the two inlets. The inlets and the at least one outlet are connected with the arcing zone such that the electric arc is extinguishable in at least three arc interruption zones by means of extinguishing flows streaming out of the at least two inlets into the arcing zone upon pressurization and introduction of a portion of the extinguishing agent in the arcing zone, and leading an amount of the extinguishing flows through the outlet out of the arcing zone.
    Type: Grant
    Filed: September 30, 2011
    Date of Patent: August 6, 2013
    Assignee: ABB Research Ltd
    Inventors: Lutz Niemeyer, Martin Seeger, Michael Schwinne, Arthouros Iordanidis
  • Patent number: 8314355
    Abstract: In a gas insulated breaking device which accommodates open/close elements including a puffer cylinder which compresses an insulation gas and extinguishes an arc and a contact finger which has a slide contact portion which is brought into slide contact with a slide contact portion of the puffer cylinder in the inside of a vessel in which the insulation gas is sealed, a relatively soft plating film is formed on the slide contact portion of the puffer cylinder, and a relatively hard plating film is formed on the slide contact portion of the contact finger, and the silver plating film of each slide contact portion has an inner layer thereof formed of a soft film and an outer layer thereof which constitutes a surface portion formed of a hard film.
    Type: Grant
    Filed: May 19, 2006
    Date of Patent: November 20, 2012
    Assignee: Mitsubishi Electric Corporation
    Inventors: Eiichi Nagao, Makiko Kawada, Tadao Minagawa, Ei Tsuchie, Kyoichi Ohtsuka
  • Patent number: 7854058
    Abstract: Methods for making and using vacuum switching devices are disclosed. A vacuum switching device has an operating rod for actuating a movable electrical contact within the device. The operating rod may be a hollow epoxy glass tube with an electrical sensor disposed within it, and there may be an elastomeric polymer filling compound disposed within the tube and encasing the sensor. The operating rod may be attached to the movable electrical contact on one end by a steel end-fitting that has been press-fit into the tube and secured with at least one cross pin. In this way, a very secure electromechanical connection may be made between the operating rod and the rest of the vacuum switching device, and the sensor is protected from shock associated with the operation of the device. Moreover, the vacuum switching device is compact and easy to construct.
    Type: Grant
    Filed: November 12, 2008
    Date of Patent: December 21, 2010
    Assignee: Cooper Technologies Company
    Inventors: Daniel Schreiber, Veselin Skendzic, E. Fred Bestel, Paul N. Stoving, Richard A. Harthun
  • Patent number: 7679021
    Abstract: An electrical switching device, especially a high-voltage circuit breaker, contains arcing contacts and nominal current contacts. At least one of the nominal current contacts has a surface formed of an arc-resistant material provided with a galvanic coating. In this configuration, the contact points can withstand high mechanical and thermal loads and at the same time maintain a high current carrying capacity.
    Type: Grant
    Filed: November 2, 2004
    Date of Patent: March 16, 2010
    Assignee: Siemens Aktiengesellschaft
    Inventors: Joachim Gericke, Volker Lehmann, Andrzej Nowakowski, Klaus Schuler
  • Patent number: 6884952
    Abstract: A contact finger module for mounting in a high-power switchgear includes at least one contact finger having a contact piece and a flexible contact piece support, which extends along a longitudinal direction and has an attachment end and a contact-making end. The contact piece overhangs the contact piece support in the opposite direction to a deflection direction, and is connected to the contact piece support at the contact-making end. The contact finger module includes at least one leaf spring, which extends along the longitudinal direction and has an attachment end at which it is connected to the attachment end of the contact piece support in the mounted state. The leaf spring can produce a force that counteracts deflection of the contact piece in the deflection direction. In the mounted state, the leaf spring can extend in the longitudinal direction at least as far as the center of the extension of the contact piece in the longitudinal direction.
    Type: Grant
    Filed: June 18, 2004
    Date of Patent: April 26, 2005
    Assignee: ABB Technology AG
    Inventors: Jean-Claude Mauroux, Patrick Huguenot
  • Patent number: 6750746
    Abstract: An electromagnetic switching device, especially a contactor, includes a base, an arc chamber removable from the base, a contact bridge support and a spring-loaded locking element. The contact bridge support projects into the arc chamber and can be displaced in a direction of actuation. The contact bridge support can be locked by the locking element when the arc chamber is taken off. The locking element is configured as a lever that is swiveled about a swiveling axis which extends in perpendicular to the direction of actuation.
    Type: Grant
    Filed: September 17, 2002
    Date of Patent: June 15, 2004
    Assignee: Siemens Aktiengesellschaft
    Inventors: Johann Bauer, Stephan Faber, Bardo Koppmann
  • Patent number: 6664494
    Abstract: A current collector, in which contact portions are free from dissolved loss even both fixed and moving contacts slidingly contact with each other, and durability as well as a current-carrying perfomance is improved, including a container, which is filled with an insulating arc-extinguishing medium and in which a cylindrical-shaped fixed contact and an torus-shaped contact disposed concentrically with the fixed contact and adapted to come into fitting contact with the fixed contact to carry current are received, and a torus-shaped current collecting member formed from a conductive material and provided on a contact portion of the torus-shaped contact.
    Type: Grant
    Filed: September 25, 2002
    Date of Patent: December 16, 2003
    Assignee: Hitachi, Inc.
    Inventors: Junzo Kida, Makoto Hirose, Tomoyuki Andou
  • Publication number: 20020153352
    Abstract: A bus container, its assembling method and a gas-insulated switchgear, in which gas treating working in a factory and at a site is reduced, an operation is made simple, and a process is shortened. In the case of connection of a container (101) and a container (102), a conductor (103) of spherical shape is kept in contact with and fixed to a contact (102f), the container (101) is caused to approach to the container (102), the conductor (103) is joined to a contact (101f).
    Type: Application
    Filed: February 21, 2002
    Publication date: October 24, 2002
    Inventors: Kenji Aoyagi, Takashi Omori, Toyokazu Tanaka
  • Patent number: 6462295
    Abstract: In a high-voltage power breaker having two rated current contact pieces and two arc contact pieces as well as an insulating nozzle, a filling body is provided, which is mounted on this insulating nozzle, surrounds the insulating nozzle in an annular shape and is composed of an electrically insulating material having a high dielectric constant, in order to influence the electric field in the isolating gap.
    Type: Grant
    Filed: July 19, 2001
    Date of Patent: October 8, 2002
    Assignee: Siemens Aktiengesellschaft
    Inventors: Hartmut Knobloch, Heinz-Helmut Schramm
  • Publication number: 20020060203
    Abstract: A contact zone (1) of a quenching chamber which is arranged rotationally symmetrical about a central axis (2) and is filled with an insulating medium, having at least two stationary consumable contacts which are in the form of contact rings (4, 15) and which, when the quenching chamber is closed, are electrically conductively connected by means of a bridging contact which is arranged centrally and can move axially. The mutually facing end surfaces of the consumable contacts are partially covered by electrically insulating covers (11, 22). The aim is to provide insulating covers which are designed to have good dielectric characteristics and are easy to install.
    Type: Application
    Filed: November 13, 2001
    Publication date: May 23, 2002
    Inventors: Lukas Zehnder, Michael Mendik
  • Patent number: 6271494
    Abstract: A high-voltage circuit breaker is described having arcing contacts, which can be driven in opposite directions, as well as corner gears that are coupled, via a driving rod, with the driven insulating nozzle surrounding the arcing contacts, with the corner gears being designed as a lever mechanism using a two-armed control lever. The one end of the control lever is shaped like a fork, with a journal that is attached to the driving rod engaging with this end. The other end of the control lever is coupled, via a reciprocating element, with the head piece of the second arcing contact, which is driven in the opposite direction.
    Type: Grant
    Filed: June 24, 2000
    Date of Patent: August 7, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventors: Hold Dienemann, Volker Lehmann, Heiner Marin
  • Patent number: 6271493
    Abstract: A high voltage disconnector comprising a fixed contact and a movable contact to the latter to produce an electrical connection between a first conductor and a second conductor, the movable contact and the fixed contact forming, when they are in contact with one another, a connector that is at an angle with respect to the first and/or second conductor, such that when the contacts are in contact with one another during operation a Lorentz force prevails which pulls the fixed and movable contacts apart and is transverse to the first or second conductor. The movable contact and the fixed contact are provided with locking devices which, when the contacts are in contact with one another, engage in one another and act in a direction parallel to the Lorentz force which is pulling the fixed and movable contacts apart and is transverse to the first or second contact.
    Type: Grant
    Filed: November 9, 1999
    Date of Patent: August 7, 2001
    Assignee: Elin Holec High Voltage B.V.
    Inventor: Ijsbrand Paulus Johannes Maria Ponsioen
  • Patent number: 6259050
    Abstract: A switching arrangement having a large burn-up reserve, contact fingers (2) are connected to a first electrical terminal via flexible bands (6) consisting of strips of, for example, copper which lie one above the other. The connecting portion (7) of the band (6), the said connecting portion adjoining the contact fingers (2) and being rigidly connected to them, is reinforced in each case by pressure welding of the strips. In the switch-off state, the bands (6) and, in part, the contact fingers (2) bear on an outwardly pointing supporting face (10), whilst, in the switch-on state, at least the contact fingers (2) and connecting portions (7) are lifted off from the supporting face (10), with the bands (6) being bent at the same time, as a result of contact with the outside of a switching pin (3) displaceable along a switching axis (1).
    Type: Grant
    Filed: May 11, 2000
    Date of Patent: July 10, 2001
    Assignee: Asea Brown Boveri AG
    Inventors: Lukas Zehnder, Ion Gavrilita, Markus Keller, Jörg Peter, Thomas Schoenemann
  • Patent number: 6239399
    Abstract: In an interrupter with a resistor insertion system, the resistor insertion system comprises two auxiliary contacts, a first of which is electrically connected to a semi-mobile permanent current contact and the second of which is electrically connected to a fixed arc contact. The two auxiliary contacts are mounted to be mobile relative to each other along a longitudinal axis so as to be able to move toward each other when the interrupter closes to make a connection that short-circuits the resistor and so as to be constrained to move together along the longitudinal axis when the interrupter closes before making the connection which short-circuits the resistor, to increase the resistor insertion time.
    Type: Grant
    Filed: September 8, 1999
    Date of Patent: May 29, 2001
    Assignee: Alstom France S.A.
    Inventor: Michel Perret
  • Patent number: 6211478
    Abstract: In a power switch, power-switch fingers of a rated-current switching arrangement, as well as contact fingers (25) of a tulip contact and a switching pin (14) of an arcing switch arrangement, or other parts, each comprise a base body (26, 28) which, at sections which are subjected to high thermal loads by the arc formation, bears a protective layer (27, 29) which is resistant to contact erosion and has been applied to the base body (27, 28) by plasma spraying in vacuum. This enables even complex and flexible parts to be made resistant to contact erosion. The protective layer (27, 29) which is preferably used is a mixture of at least 10% (by weight), in particular at least 50% (by weight) of high-melting metal, such as W, Mo, Ir, and lower-melting metal, such as Cu, Ag, Ti, Fe, e.g. 80% (by weight) W and 20% (by weight) Cu, while the base body used is preferably made from Cu, Ag. Fe, steel, Al or a flexible copper alloy, such as CuBe, CuCr or CuCrZr.
    Type: Grant
    Filed: August 16, 1999
    Date of Patent: April 3, 2001
    Assignee: Asea Brown Boveri AG
    Inventors: Thomas Schoenemann, Lukas Zehnder
  • Patent number: 6100489
    Abstract: In the switched-on position, under the influence of contact forces generated by elastic deflection or else by mechanical spreading, or spreading caused by the attraction of parallel currents or repulsion of antiparallel currents, of a switching pin (5) , the switching pins presses against the inner side of a first switching ring (4), which is rigid for the purpose of avoiding mechanical overloading and securing sufficient consumable reserves. By way of example, a support (30) of the switching pin (5) is adjoined by two parallel, elastic extensions (52a, 52b), which are separated by a slot (53) and respectively support a contact member (54a; 54b) by means of a connecting element (55a; 55b) forming half a screw thread, with the result that said contact member is in each case offset by 180.degree. relative to the extension (52a; 52b).
    Type: Grant
    Filed: April 13, 1999
    Date of Patent: August 8, 2000
    Assignee: Asea Brown Boveri AG
    Inventors: Lukas Zehnder, Robert Anderes, Christian Dahler, Kurt Kaltenegger, Thomas Schoenemann, Klaus-Dieter Weltmann
  • Patent number: 5981893
    Abstract: This switching device has a contact arrangement which is equipped with erosion-resistant contacts and comprises at least one contact which moves along a central axis (2) and at least one mating contact which is provided for receiving the moving contact. One of the two contacts has a finger cage (25) which is provided with individual, sprung contact fingers (13) which are spaced apart from one another by radial slots (26) extended in the direction of the central axis (2). Means are provided which prevent the side edges (29) of the contact fingers (13) being able to touch in the region of the contact surfaces (27) in the front part of the contact fingers (13) when said contact fingers (13) are drawn together in the direction of the central axis (2) , such that welding of the edges (29) of the contact fingers (13) cannot occur.
    Type: Grant
    Filed: September 22, 1997
    Date of Patent: November 9, 1999
    Assignee: Asea Brown Boveri AG
    Inventors: Daniel Bleiker, Jadran Kostovic, Herbert Schifko
  • Patent number: 5977502
    Abstract: The gas circuit breaker has a configuration such that a stationary contact section and a movable contact section are arranged in an arc-extinguishing gas sealed container, to face each other, and the movable contact section includes a hollow operating rod having an exhaust hole at its rear portion, a movable cylinder arranged around the rod, a hollow movable arc contact provided on the movable cylinder and an insulating nozzle surrounding the movable arc contact. The movable contact section further includes a stationary piston portion insertable/removable inside the movable cylinder, and the space formed by the movable cylinder and the current collecting cylinder fixed to the stationary piston portion is partitioned by a parting plate into a thermal pressure elevation room space at front side and a compression room space at rear side.
    Type: Grant
    Filed: January 27, 1999
    Date of Patent: November 2, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Mizoguchi, Tadashi Mori, Hiromichi Kawano, Katsumi Suzuki, Mitsuru Toyoda
  • Patent number: 5929409
    Abstract: This power breaker has at least one quenching chamber, which is filled with an insulating medium, is of cylindrical design, extends along a central axis (2) and has a power current path, having two stationary consumable contact arrangements (5, 6) which are arranged on the central axis (2), are at a distance from one another in the axial direction and are arranged in the power current path. In the connected state, the consumable contact arrangements (5, 6) are electrically conductively connected by means of a moving bridging contact. An arc zone (24) is provided between the stationary consumable contact arrangements (5, 6). A rated current path, which is provided with moving rated current contacts, is arranged in parallel with the power current path. The bridging contact is arranged in the interior of the consumable contact arrangements (5, 6) extended along the central axis (2).
    Type: Grant
    Filed: April 3, 1997
    Date of Patent: July 27, 1999
    Assignee: Asea Brown Boveri AG
    Inventors: Lukas Zehnder, Robert Anderes, Christian Dahler, Kurt Kaltenegger, Bodo Bruhl
  • Patent number: 5902978
    Abstract: This power breaker has at least one quenching chamber, which is filled with an insulating medium, is of cylindrical design, extends along a central axis (2) and has a power current path, having two stationary consumable contact arrangements (5, 6) which are arranged on the central axis (2), are at a distance from one another in the axial direction and are arranged in the power current path. In the connected state, the consumable contact arrangements (5, 6) are electrically conductively connected by means of a moving bridging contact. An arc zone (24) is provided between the consumable contact arrangements (5, 6). A rated current path is arranged in parallel with the power current path. The power breaker is provided with at least one source for a highly pressurized insulating medium. The medium passes from this source directly into the arc zone (24), through at least one injection channel (62, 63). This high-pressure injection considerably improves the breaking capacity of the power breaker.
    Type: Grant
    Filed: April 3, 1997
    Date of Patent: May 11, 1999
    Assignee: Asea Brown Boveri AG
    Inventors: Lukas Zehnder, Robert Anderes, Bodo Bruhl, Christian Dahler, Ion Gavrilita, Joachim Stechbarth, Kurt Kaltenegger
  • Patent number: 5869796
    Abstract: A contact device has a pair of flanges which extend inward in the radial direction from both ends of an annular shield, and a plurality of contact pieces which are arrayed in the circumferential direction in a space formed by the shield and the pair of flanges, the axial direction thereof being matched to the parallel direction with the axial center of the shield. Contact sections are provided on the outer peripheral surfaces at both ends of each contact piece. The contact device also has a plurality of rod-shaped elastic members disposed in the circumferential direction on the flanges, each of the elastic members being cantilever-fixed to the flange in such a manner that one end thereof is secured to an inner edge surface of the flange and the other end thereof is allowed to extend along the axial center of the shield into a space formed by the shield and the pair of flanges. The rod-shaped elastic members elastically support the contact pieces to restrict the contact pressure of the contact sections.
    Type: Grant
    Filed: June 11, 1997
    Date of Patent: February 9, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Setsuyuki Matsuda, Hiroyuki Hama
  • Patent number: 5770828
    Abstract: The circuit-breaker has a quenching chamber which is filled with an insulating medium, is of cylindrical design and has a quenching zone extending along a longitudinal axis. In addition, it has a fixed contact arrangement, which is arranged in the course of a main current path, and a moving contact arrangement. Furthermore, a blowing volume is provided which stores the increased pressure of the insulating medium which occurs during a disconnection process. At least one contact link, which has two contact points, electrically conductively connects the fixed contact arrangement and the moving contact arrangement to one another in the connected position. The contact link is also mounted to a holder such that it can rotate. The side of the contact link which interacts with the fixed contact arrangement is acted on by a force directed outward in the radial direction with respect to the longitudinal axis.
    Type: Grant
    Filed: May 17, 1996
    Date of Patent: June 23, 1998
    Assignee: ABB Research Ltd.
    Inventor: Lutz Niemeyer
  • Patent number: 5629506
    Abstract: An AC contactor having a high recovery voltage strength includes a contact assembly and a high recovery voltage gas system coupled to the contact assembly. The contact assembly includes two contact pads per electrical phase, with one of the contact pads being attached to a positioning device that selectively disposes the contact pad between a closed circuit position and an open circuit position. The high recovery voltage gas system includes a thermal gas evolving medium for introducing a high recovery voltage strength gas into the gap between the contact pads, which gas has a high glow discharge cathode voltage fall value, as determined for silver-based contacts, of not less than about 300 volts, and typically greater than about 500 volts. The high recovery voltage strength gas typically comprises carbon monoxide, carbon dioxide, water vapor, or the like. The thermal gas evolving medium typically is as a Group IA carbonate (e.g., sodium bicarbonate), and is disposed in the contact assembly.
    Type: Grant
    Filed: June 15, 1994
    Date of Patent: May 13, 1997
    Assignee: General Electric Company
    Inventors: Lawson P. Harris, Herman L. Finkbeiner, Minyoung Lee
  • Patent number: 5502435
    Abstract: A method and system are provided for monitoring the pressure of gas in a gas filled circuit breaker container based on a temperature compensated gas pressure signal which is compared with a signal representing a desired gas pressure in the container to provide a signal indicating a gas leak when the actual pressure is less than the desired pressure. In addition to identifying a gas leak, the method and system is operable to deactivate the circuit breaker when the actual pressure decreases below a predetermined low pressure, to determine the gas leak rate and to deactivate the circuit breaker if the leak rate is greater than a predetermined acceptable rate and, otherwise, to determine the time required for the pressure to decrease to the unacceptable low pressure, and to activate an alarm, visual display and/or recording of information in response to certain detected conditions with respect to the gas pressure.
    Type: Grant
    Filed: April 6, 1994
    Date of Patent: March 26, 1996
    Inventor: Douglas E. Ralston
  • Patent number: 5483031
    Abstract: A gas-insulated disconnector includes a movable contact disposed above a fixed contact within a housing filled with an insulating gas. The movable contact is electrically coupled to an upper support member through a finger-type sliding contact 3 which is dip-shaped and is fixed to the support member at the upper end thereof and is in sliding contact with the interior surface of the cup-shaped movable contact. An operating rod connecting the movable contact to a link mechanism is slidably supported by a support cylinder extending within the movable contact. Thus small metal particles generated by the abrasion of the contact surfaces at the side of the movable contact is contained within the movable contact and do not drift into the gas-insulated gap.
    Type: Grant
    Filed: November 5, 1993
    Date of Patent: January 9, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Setsuyuki Matsuda
  • Patent number: 5464956
    Abstract: A loadbreak switch is provided that utilizes a pivotally mounted movable jaw contact and a main stationary contact that is positioned in the middle of an arc runner. For operation at voltages 15 kV and above, the switch utilizes a shunt contact that bridges the arc runner and that is above and coplanar with the main stationary contact. A magnetic field is developed by the current that flows through a coil of wire disposed around the arc runner. This configuration when utilized in an environment of insulating gas, provides efficient extinguishing of arcs upon opening of the contacts. Further, the open jaw contact is easily visible to establish an open gap.
    Type: Grant
    Filed: April 8, 1994
    Date of Patent: November 7, 1995
    Assignee: S&C Electric Company
    Inventors: Edward A. Steele, James K. Niemira
  • Patent number: 5453591
    Abstract: A vaporizable material, for example, a silicone, that is buried beneath the surface of a Teflon nozzle for a sulfur hexafluoride power circuit breaker in an area of the nozzle which is exposed to abrasion and wear due to arc products. In a similar manner, aluminum or titanium or some other vaporizable material is buried beneath the surface of the contact of the circuit interrupter which is exposed to abrasion and wear. When the buried layers are exposed due to abrasion of their covering surfaces, these materials will be vaporized and their presence will be sensed by sensors within the circuit interrupter, thus revealing some predetermined degree of wear of the surfaces of the nozzle and contact and other surfaces within the circuit interrupter which may also be subject to abrasion by arcing or arc products. When aluminum is used as the vaporizable material for the contact, it also senses the presence of flashover to aluminum exterior housings.
    Type: Grant
    Filed: April 5, 1994
    Date of Patent: September 26, 1995
    Assignee: ABB Power T&D Company Inc.
    Inventor: Nicholas J. Stroud