Patents Examined by S. Jackson
  • Patent number: 5285346
    Abstract: A control circuit for protecting a power device has been provided. The control circuit has a thermal shutdown circuit for activating a first SCR when the temperature of the control circuit exceeds a predetermined temperature. Additionally, the control circuit has a DSAT detection circuit for activating the first SCR in response to an external signal. The first SCR is coupled across an input terminal and the common terminal of the control circuit. When the first SCR latches, it functions to subsequently latch a second SCR that is coupled across the output and common terminals. The second SCR functions to rapidly discharge the voltage appearing across the output and common terminals.Additionally, the control circuit includes an input level sensitive circuit which may be utilized to deactivate various circuitry depending upon the current level of an input signal supplied to the control circuit.
    Type: Grant
    Filed: December 13, 1991
    Date of Patent: February 8, 1994
    Assignee: Motorola, Inc.
    Inventors: Robert B. Davies, David F. Mietus, Paul T. Bennett
  • Patent number: 5283708
    Abstract: A device protects an electric load, such as a motor, from excessive current levels. The current flows from a source to the load through a switch and a primary winding of a current sensing transformer. The voltage across a secondary winding of the current sensing transformer is rectified to produce a voltage which is measured to determine the level of current through the load. The voltage across the secondary winding also powers components of the device. In a first mode of operation, current from the secondary winding is applied to charge a power supply capacitor. In a second mode of operation the level of the rectified voltage is sensed to produce a sample of the level of the current flowing through the load. From this sample the change in temperature of the load since a previous sample is calculated and used to derive the present load temperature. When the present load temperature exceeds a defined threshold level, the switch is opened to disconnect the load from the electricity source.
    Type: Grant
    Filed: September 23, 1992
    Date of Patent: February 1, 1994
    Assignee: Allen-Bradley Company, Inc.
    Inventor: Richard W. Waltz
  • Patent number: 5278720
    Abstract: A surge suppressor for a high frequency transmission line contains a microstrip architecture comprising a dielectric sheet on a first side of which a signal conductor stripe layer is formed and on a second side of which a ground plane conductor layer is formed. The strip layer is disposed along a generally central linear region of the first surface, so as to facilitate direct connection to the center conductor of a pair of end connectors, such as type F coaxial connectors. The ground plane conductor layer is attached to the shield layer of the coaxial connectors. A gas discharge tube is coupled between a first location of the stripe layer and the ground plane layer. The discharge device may be mounted on the first side of the microstrip structure and is connected to the ground plane layer on the opposite surface by way of a plated through hole.
    Type: Grant
    Filed: September 20, 1991
    Date of Patent: January 11, 1994
    Assignee: Atlantic Scientific Corp.
    Inventor: Anthony O. Bird
  • Patent number: 5274527
    Abstract: The invention is directed to a housing for plug-in connections between at least one energy source and a plurality of energy consumers. They are used in the commercial area, e.g. in office and production devices, and in the home, e.g. in video, TV and household appliances. To prevent unauthorized use of such appliances and reduce the risk of injury it is suggested to arrange the plug-in contacts (8) serving to produce the connection on a plane whose surface can be locked with a cover (2). A lock unit (21) which is arranged in the housing (1) so as to be hidden is constructed as locking mechanism (11) and as power switch (5) simultaneously for all connections.
    Type: Grant
    Filed: December 23, 1991
    Date of Patent: December 28, 1993
    Inventor: Werner Retzlaff
  • Patent number: 5274524
    Abstract: A programmable protection circuit comprises three identical units connected between a common point (C) and a first conductor (A), a second conductor (B) and ground (M). Each unit comprises the anti-parallel arrangement of a thyristor (T) and a diode (D), a bipolar transistor (TR) being connected between the gate and anode of the thyristor, the anodes of the thyristors being connected to the common point and the base terminal of each unit constituting a programmation terminal and being connected to a device defining a voltage threshold. Each device defining a voltage threshold is a zener diode (Z1, Z2, Z3) connected between each base terminal and the common point.
    Type: Grant
    Filed: December 6, 1991
    Date of Patent: December 28, 1993
    Assignee: SGS-Thomson Microelectronics S.A.
    Inventors: Robert Pezzani, Eric Bernier
  • Patent number: 5271484
    Abstract: The present invention is directed to notifying a user of an arriving elevator car in response to a hall call registered by the user, wherein notification occurs a threshold time value before elevator car arrival. In the preferred embodiment, an elevator car is assigned to a floor in response to a hall call. The amount of time required for the assigned elevator car to arrive at the floor is determined and compared with the threshold time value. If the arrival time is greater than the threshold time value, the system reexamines assignment, possibly reassigning a different elevator car to respond to the hall call. The arrival time of the assigned (or newly assigned) elevator car is again determined, and this process continues until the arrival time is less than or equal to the threshold time value. When the arrival time is less than or equal to the threshold time value, the hall lantern at the door of the assigned elevator car is energized, e.g., illuminated and/or sounded.
    Type: Grant
    Filed: April 10, 1991
    Date of Patent: December 21, 1993
    Assignee: Otis Elevator Company
    Inventors: Zuhair S. Bahjat, Joseph Bittar
  • Patent number: 5270896
    Abstract: A personnel protection system for electrical connections is disclosed, which is of the type that differentially senses the current flow between the power lead and the return lead (or between two power loads) is provided with an unbalancing impedance which makes the current difference between the two leads sufficiently high to trip the device and cause the power to be disconnected. A utilization device is similarly provided with an imbalanced impedance. However, that impedance is calculated to counteract the current imbalance caused by the first impedance, so that when the cable is connected to the utilization device, the current balance between the two conductors is restored, and power connection is maintained in the cable. Thus, the system does not provide continuous power unless predetermined conditions considered safe for securing the power are fully satisfied.
    Type: Grant
    Filed: November 14, 1991
    Date of Patent: December 14, 1993
    Assignee: Hubbell Incorporated
    Inventor: Thomas M. McDonald
  • Patent number: 5270897
    Abstract: A personnel protection system for electrical connections is disclosed, which is of the type that differentially senses the current flow between the power lead and the return lead (or between two power loads) is provided with an unbalancing impedance which makes the current difference between the two leads sufficiently high to trip the device and cause the power to be disconnected. A utilization device is similarly provided with an imbalanced impedance. However, that impedance is calculated to counteract the current imbalance caused by the first impedance, so that when the cable is connected to the utilization device, the current balance between the two conductors is restored, and power connection is maintained in the cable. In addition, the current flow in the second impedance is sensed and, if it is not at the correct level, electrical power to the load is disconnected in the same manner as when an imbalance occurs.
    Type: Grant
    Filed: November 14, 1991
    Date of Patent: December 14, 1993
    Assignee: Hubbell Incorporated
    Inventors: Thomas M. McDonald, W. Reid Smith-Vaniz
  • Patent number: 5260848
    Abstract: A material and device for electronic circuitry that provides protection from fast transient over-voltage pulses. Conductive particles are dispersed in an insulating matrix to provide material having foldback switching characteristics. The foldback switching characteristics of the material are determined by the spacing between the conductive particles (which must be at least 1000 Angstroms) as well as by the electrical properties of the insulating matrix.
    Type: Grant
    Filed: July 27, 1990
    Date of Patent: November 9, 1993
    Assignee: Electromer Corporation
    Inventor: Richard K. Childers
  • Patent number: 5255150
    Abstract: A grounding device is automatically operable to create a short circuit in the event of a mechanical fault on a pole line. The grounding device is placed below, and close to, each phase line on a pole line. When the phase line moves down, because of a broken wire or the like, the wire engages a sensing member which moves down and causes projection of a grounding tongue. The sensing member has surfaces that direct the wire to a contact area; and, the wire moves the sensing member down, causing projection of a grounding tongue, which will contact the phase line. Before actuation, the tongue, and all portions at ground potential, are enclosed within an insulating housing. A transmitter may also be actuated to broadcast the location of the grounding device.
    Type: Grant
    Filed: December 11, 1991
    Date of Patent: October 19, 1993
    Inventors: J. Ronald Young, Dorothy J. Young
  • Patent number: 5245496
    Abstract: The present invention features a system and method for determining an overload condition in either DC or AC motors. The system of the invention is non-invasive, in that the impedance of or the current in the line is not affected by the system measurement of the line current being drawn by the motor. A pair of current sensing toroids having variable permeability is placed about the lead-wire(s) of the motor, without interrupting the current path in the line. The sensors each consists of metallic glass that changes its permeability as a function of an external magnetic field. Current in the lead-wire(s) creates a magnetic field. The inductance of the sensors varies in direct proportion to the magnetic field. A controller starts the motor. As the motor starts, the pattern of load current drawn by the motor is measured and stored in memory. The sensors are connected to an oscillator circuit, whose output frequency is proportional to the current drawn by the motor load.
    Type: Grant
    Filed: August 16, 1991
    Date of Patent: September 14, 1993
    Inventors: Nam H. Kim, Sang K. Yon
  • Patent number: 5245497
    Abstract: A transformer including a bobbin having a primary winding frame and a secondary winding frame, a primary coil wound around the primary winding frame, a secondary coil wound around the secondary winding frame, a pair of connection pins electrically connected to a power source A projection which can be broken or bent is provided on the bobbin. The wire of the primary coil is hitched over the projection and then wound to form the primary coil, and the projection is therafter broken or bent to loosen the primary coil. A discharge means is also provided to cause a discharge between the pair of connection pins when a high voltage is applied therebetween.
    Type: Grant
    Filed: July 24, 1991
    Date of Patent: September 14, 1993
    Assignee: Nippon Desan Corporation
    Inventors: Seiki Shibui, Masaaki Sano
  • Patent number: 5241446
    Abstract: Overvoltage protector unit for use in a well in which an overvoltage protection device is mounted in a grounding housing and electrically separates a conductor pin in the housing from the housing during normal voltage conditions. The conductor pin is mounted within a flame resistant resilient elastomeric dielectric support which also electrically isolates it from the housing. The support cushions the pin before installation of the unit and the unit is unlikely to suffer damage during storage or transit upon the protection device failing, the resilient support flexes to enable line to ground contact to be established.
    Type: Grant
    Filed: November 22, 1991
    Date of Patent: August 31, 1993
    Assignee: Northern Telecom Limited
    Inventors: Michael R. Cosley, Arnold M. Ladd, Casimir Z. Cwirzen
  • Patent number: 5239439
    Abstract: A power protection circuit for detecting the level of output voltage source from a power supply, comprises a first detector for detecting a first output state of the power supply, a second detector for detecting a second output state of the power supply, an abnormality detector for recognizing the detecting states of the first and second detection means and detecting an abnormality state from the outputs of the power supply and generating an abnormality signal responsive to said abnormality state, an initial-ineffective circuit for making said abnormality signal ineffective when source voltage is supplied at the first stage, a driver for receiving said abnormality signal from said abnormality detecting means and generating continuous abnormality signal once said abnormality state is occurred.
    Type: Grant
    Filed: March 29, 1991
    Date of Patent: August 24, 1993
    Assignee: SamSung Electronics Co., Ltd.
    Inventor: Kyoung-Geun Lee
  • Patent number: 5224008
    Abstract: A surge protection system has a surge protection device comprising a semiconducting disc element disposed between two electrodes. The element is operable to selectively conduct electrical energy between the electrodes in providing a first level of surge protection for the circuit, and the electrodes are adapted to move toward each other to maintain a short circuit condition between the electrodes in the event the element is destroyed in providing a second relatively greater level of surge protection. The semiconducting element provides a critical energy conduction path between a selected limited portion of one side of the element and the other element side along which destruction of the element preferentially occurs due to overheating in providing the second level of surge protection.
    Type: Grant
    Filed: June 25, 1991
    Date of Patent: June 29, 1993
    Assignee: Texas Instruments Incorporated
    Inventors: Pravin Popat, Diethard Unterweger, Ronald J. Candelet
  • Patent number: 5224009
    Abstract: A duplex receptacle has a housing base with insulating wall elements to which a insulating circuit board supporting a surge suppressor circuit is fit. The surge suppressor can be preassembled and located as a compact unit in the housing with connective connections to each of the power conductors and ground. The device also has an insulated ground feature with each ground contact extending into housing base projections which have openings accommodating an isolated ground strap to which the internal ground contacts are joined. The features of the invention are well suited for shallow receptacles as may be fit within outlet boxes of a depth of no more than about 11/2 inches. In addition, a back insulating cover is provided that fits over the isolated ground strap and base projections. The back cover shields the ground strap.
    Type: Grant
    Filed: May 21, 1992
    Date of Patent: June 29, 1993
    Assignee: Hubbell Incorporated
    Inventor: John J. Misencik
  • Patent number: 5224011
    Abstract: A protective relay system for generation apparatus connectable to a three-phase alternating current electrical utility system. The relay system includes a dual processing architecture wherein a digital signal processor executes all the signal-processing algorithms, and a separate microprocessor is used for input/output data processing. A dual-ported RAM is used to effect a fast communication link between the digital signal processor and the microprocessor to accomplish high-speed protective relaying functions to selectively trip and close a circuit breaker at a generator or cogenerator site, or that which connects it to an electric utility system.
    Type: Grant
    Filed: April 19, 1991
    Date of Patent: June 29, 1993
    Assignee: Gas Research Institute
    Inventors: Murty V. V. S. Yalla, David C. Vescovi, Thomas R. Beckwith
  • Patent number: 5220480
    Abstract: A surge arrester for mounting on a transformer having two line-potential terminals and a neutral terminal. The arrester includes two high energy, low voltage metal oxide varistor disks, each MOV disk having one side connected to an electrode that is electrically connected to one of the line-potential terminals and having the other side of the MOV disks electrically connected to a neutral electrode that is electrically connected to the neutral terminal of the transformer. The MOV disks shunt any current surge to ground upon the application of a predetermined voltage across the disks. In the preferred embodiment, the electrodes and MOV disks are housed within a thermoplastic elastomer housing filled with a potting compound of a resilient elastomeric material. The potting compound completely insulates and seals the electrical connections and MOV disks.
    Type: Grant
    Filed: October 16, 1990
    Date of Patent: June 15, 1993
    Assignee: Cooper Power Systems, Inc.
    Inventors: Stanley S. Kershaw, Jr., Gary L. Goedde, Robert N. Schettler
  • Patent number: 5218508
    Abstract: A high voltage surge arrester comprise plurality of low voltage surge arresters coupled together in a series parallel network, the low voltage arresters being of a high strength polymeric type consisting of a solid core of varistor blocks encased within a glass fibre reinforced plastics shell and housed in a shedded polymeric housing, and the series parallel network consisting of a plurality of series connected stages each of which comprises a generally annular mounting plate formed with an integral corona discharge suppression ring and a plurality of the low voltage surge arresters mounted to the mounting plate at uniformly spaced apart positions. The subject high voltage, series parallel surge arrester can replace conventional station class porcelain housed surge arresters, which are expensive, troublesome to transport and instal and liable to electrical problems, and avoids all of these problems whilst providing numerous significant advantages.
    Type: Grant
    Filed: February 7, 1990
    Date of Patent: June 8, 1993
    Assignee: Bowthorpe Industries Limited
    Inventor: Rodney M. Doone
  • Patent number: 5212616
    Abstract: An improved latch-up protection circuit is disclosed which prevents damage to a CMOS integrated circuit chip due to transient surges or internal-circuitry initiated latch-ups and which clears any latch-up condition or SCR mode. In each embodiment, the latch-up protection circuit is integrated with an on-chip voltage regulation circuit which provides on-chip power to the internal chip circuitry. A first approach to implementing the latch-up protection circuit is to detect an average current through the power transistor of the voltage regulation circuit over a few microseconds. Should the average current exceed a preset value, then the power transistor is turned off and the power (V.sub.DDI) supplied to the internal chip circuitry is reduced to zero, thereby removing the latch-up condition. In a second approach, the on-chip voltage (V.sub.DDI) supplied to internal chip circuitry is compared with a reference voltage signal representative of the occurrence of a latch-up condition, i.e.
    Type: Grant
    Filed: October 23, 1991
    Date of Patent: May 18, 1993
    Assignee: International Business Machines Corporation
    Inventors: Sang H. Dhong, Robert L. Franch