Shunt Connected Capacitors Patents (Class 361/17)
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Patent number: 11402437Abstract: A real-time detection/recovery system of a power line failure in a power distribution system, which immediately alerts, shuts off, and recovers power in real-time when a disconnection, a resistance increase, a contact failure, a half-disconnection, or a short circuit occurs in a single-phase power supply side of a three-phase or single-phase power distribution system. A power distribution system can be provided with one or more of a power supply side detection/recovery device and a load side detection/recovery device. The power supply side and load side detection/recovery devices can recover, shut off, alert, notify, or control an electrical failure in a power supply line of a single-phase or three-phase power supply by forming a neutral point with an element electrically/electronically connected to the single-phase or three-phase power supply to ground the neutral point or detect a potential difference between the neutral point and the ground.Type: GrantFiled: December 11, 2017Date of Patent: August 2, 2022Assignees: NAEUN ENERGY CO., LTD.Inventors: Na Un Kim, In Tae Kim, Do Woon Kim
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Patent number: 11063424Abstract: An adaptive protection method for impedance of parallel capacitors comprises monitoring a terminal voltage and current of the capacitor; automatically calibrating the initial impedance of the capacitor when the capacitor is put into operation; calculating a real-time impedance of the capacitor during operation, dynamically updating the actual impedance of the capacitor periodically; comparing the real-time impedance of the capacitor with the actual impedance, updating the actual impedance if the relative value of the modulus of the real-time impedance change does not exceed the dynamic update limit threshold and the dynamic update reaches update period; generating an update failure alarm if the relative value of the modulus of the real-time impedance change exceeds the dynamic update limit threshold; generating a protection alarm if the relative value of the modulus of the real-time impedance change satisfies the protection alarm condition and the delay time is reached; and protecting the trip outlet if the rType: GrantFiled: July 11, 2017Date of Patent: July 13, 2021Assignees: NR ELECTRIC CO., LTD, NR ENGINEERING CO., LTDInventors: Zhongpeng Song, Li Ding, Qunbing Yu, Zhen Jin, Shu Xu, Kaida Dong
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Patent number: 10903833Abstract: A control device for commercially available high voltage capacitor switches to close the circuit on electric utility power factor correction shunt capacitors or motor start assistance shunt capacitors precisely as each phase of the AC power source passes through zero volts.Type: GrantFiled: December 8, 2017Date of Patent: January 26, 2021Assignee: VALQUEST SYSTEMS, INC.Inventors: James L Landes, Evan Fritts
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Patent number: 10305275Abstract: A data interface with overvoltage protection circuitry includes a bus interface and power rectification stage configured to provide supply and return voltages for the data interface and overvoltage protection circuitry, a first power level overvoltage protection circuit, a second power level overvoltage protection circuit, a DALI endpoint power output port, a power supply for a DALI endpoint device drawing current from the power output port, a receiver configured to receive signals on the DALI bus, and, a transmitter configured to send signals on the DALI bus.Type: GrantFiled: July 5, 2016Date of Patent: May 28, 2019Assignee: CURRENT LIGHTING SOLUTIONS, LLCInventors: Tamas Daranyi, Lajos Csibi, Levente Kovacs, Gabor Pap
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Patent number: 9396866Abstract: A device for mitigation Geomagnetic Induce Currents in the power distribution network is described. It may be connected to the neutral of a star-connected three-phase transformer of the power distribution system to ground without compromising its basic insulation, operation or integrity of the system. It requires a circuit having a surge arrester resistor having an adaptive nonlinear negative volt-ampere which is inserted from the transformer neutral to ground and a ground switch connected to the ground and also connected to the surge arrester. The device has two different current paths: whenever there is no GIC the switch remains closed and current flows from the transformer to the ground via the ground switch. Under Geomagnetic Induce Currents, the ground switch opens, allowing the induced current to flow from the transformer to the ground via the surge arrester.Type: GrantFiled: November 4, 2013Date of Patent: July 19, 2016Inventor: Alberto Raul Ramirez
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Patent number: 9048725Abstract: The invention relates to an electric device with a winding (12) and means for inducing a current in the winding. A bridge circuit (400) electrically connects the winding (12) to a load (13). According to the invention the bridge circuit (400) includes capacitor means (401, 402), which is adapted for obtaining resonance with the impedance of the winding (12).Type: GrantFiled: December 9, 2010Date of Patent: June 2, 2015Assignee: Seabased ABInventors: Mats Leijon, Cecilia Bostrom, Mikael Eriksson
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Patent number: 8575941Abstract: An apparatus and method is provided for identifying a faulted phase in at least one shunt capacitor bank. The apparatus generally includes a sampling circuit for sampling current or voltage signals associated with the shunt capacitor bank. A microcontroller is coupled to the sampling circuit and programmed to measure a compensated neutral point phase angle from the sampled signal, and compare the compensated neutral point phase angle with a fixed reference phase angle to identify the faulted phase of the shunt capacitor bank. The method generally includes the steps of sampling a current or voltage signal associated with the shunt capacitor bank, determining a compensated neutral point phase angle from the sampled signal, and comparing the compensated neutral point phase angle with a fixed reference phase angle to identify the faulted phase of the shunt capacitor bank. The invention also relates to an apparatus and method for identifying the location of the fault (e.g.Type: GrantFiled: September 8, 2009Date of Patent: November 5, 2013Assignee: Schweitzer Engineering Laboratories IncInventors: Satish Samineni, Casper A. Labuschagne
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Patent number: 8295494Abstract: One or more attributes (e.g., pan, gain, etc.) associated with one or more objects (e.g., an instrument) of a stereo or multi-channel audio signal can be modified to provide remix capability. An audio decoding apparatus obtains an audio signal having a set of objects and side information. The apparatus obtains a set of mix parameters from a user input and an attenuation factor from the set of mix parameters. The apparatus then generates a plural-channel audio signal using at least one of the side information, the attenuation factor or the set of mix parameters.Type: GrantFiled: August 12, 2008Date of Patent: October 23, 2012Assignee: LG Electronics Inc.Inventors: Hyen-O Oh, Yang Won Jung, Christof Faller
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Patent number: 8121318Abstract: The two channel audio surround sound circuit with automatic level control includes a right amplifier, a left amplifier, a right automatic level control and a left automatic level control. A right input is coupled to a positive input of the left amplifier through the right automatic gain control. The right input is coupled to a negative input of the right amplifier and coupled to the output of the right amplifier with one resistor. A left input is coupled to a positive input of the right amplifier through the left automatic gain control. The left input is coupled to a negative input of the left amplifier and coupled to the output of the left amplifier with another resistor.Type: GrantFiled: May 8, 2008Date of Patent: February 21, 2012Inventors: Paul R. Ambourn, Earl J. Slafon
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Patent number: 7939905Abstract: According to an embodiment of the present invention, an electrostatic breakdown protection method protects a semiconductor device from a surge current impressed between a first terminal and a second terminal, the semiconductor device including: a diode impressing a forward-bias current from the first terminal to the second terminal; and a bipolar transistor impressing a current in a direction from the second terminal to the first terminal under an ON state, a continuity between a collector terminal and an emitter terminal of the bipolar transistor being attained before a potential difference between the first terminal and the second terminal reaches such a level that the diode is broken down.Type: GrantFiled: June 4, 2007Date of Patent: May 10, 2011Assignee: Renesas Electronics CorporationInventor: Takayuki Nagai
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Publication number: 20090079191Abstract: A power generation system includes: a prime mover; an electrical machine coupled to the prime mover and configured for converting mechanical power to electrical power, the electrical machine having a power factor of less than or equal to 0.7; a reactive power supply assembly coupled to the electrical machine and configured to supply reactive power to the electrical machine; and a power electronic converter coupled to the reactive power supply assembly and configured for transferring power from the electrical machine to a grid.Type: ApplicationFiled: September 26, 2007Publication date: March 26, 2009Applicant: GENERAL ELECTRIC COMPANYInventors: Jorge Mari, Michal-Wolfgang Waszak, Simon Schramm
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Patent number: 7345889Abstract: A method and system for reducing the release of high frequency electromagnetic energy into the environment is disclosed, wherein local regions of distributed capacitance are embedded within a printed circuit board (PCB) and adjacent the PCB conductive traces act as low pass filters and thus increase the rise and/or fall times occurring on such traces. The present invention increases very short rise and/or fall times (e.g., 200 picoseconds or less) without degrading or detrimentally affecting other signal characteristics. The present invention does not substantially affect the voltage amplitude and does not affect the bit period when lengthening the rise and/or fall time. Also, the present invention does not induce any timing jitter that may cause synchronization problems within the system.Type: GrantFiled: September 28, 2004Date of Patent: March 18, 2008Assignee: Avaya Technology Corp.Inventor: David Norte
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Patent number: 7030769Abstract: A circuit breaker with a thermal/magnetic trip device incorporates a monitor that senses the temperature of the bimetal and the amplitude of the load current to distinguish between a thermal and a magnetic trip. If the temperature of the bimetal is above a selected value when the circuit breaker trips, a “THERMAL” trip light emitting diode (LED) is energized, while a high load current at the time of a trip lights a “MAG” trip LED. The monitor also energizes an “ARC” LED in response to an arc fault signal from an AFCI at the time of trip, or a “GRD” LED in response to a ground fault trip. If a trip sensor, which monitors load voltage does not detect opening of the circuit breaker contacts when an arc fault or ground fault signal is generated, the corresponding LED is flashed to indicate the failure to trip. The monitor also has a “SURGE” LED to indicate a voltage surge in the protected distribution system as detected by a surge detector built into the circuit breaker.Type: GrantFiled: November 13, 2003Date of Patent: April 18, 2006Assignee: Eaton CorporationInventor: Theodore J. Miller
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Patent number: 6975489Abstract: A bypass capacitor having a given capacitance is arranged on the power/ground line adjacently to a driver circuit in a chip to reduce an effect of transient phenomenon at switching. The capacitance of the bypass capacitor is preset so as to be larger than a parasitic capacitance of the driver circuit to prevent the characteristic impedance of the power/ground line from being higher than the characteristic impedance of internal wiring.Type: GrantFiled: January 23, 2003Date of Patent: December 13, 2005Assignees: NEC Corporation, Oki Electric Industry Co., Ltd., Sanyo Electric Co., Ltd., SHARP Kabushiki Kaisha, Sony Corporatoin, TOSHIBA Corporation, Fujitsu Limited, Matsushita Electric Industrial Co., Ltd., Rohm Co., Ltd., Renesas Technology Corp.Inventors: Kanji Otsuka, Tadatomo Suga, Tamotsu Usami
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Patent number: 6548769Abstract: A circuit breaker includes an opening and closing mechanism section with an opening and closing lever, and an alarm-outputting plate operating in response to a tripping operation. A case for the circuit breaker has a plurality of switch housing sections formed on a top side thereof, in which are installed an auxiliary switch for detecting an ON/OFF state of a main circuit contact and/or an alarm switch for detecting a tripping operation. The opening and closing lever and the alarm-outputting plate have outputting projecting pieces, respectively, laterally spaced apart from each other corresponding to the respective housing sections, for transmitting mechanical output signals to the switches. When the auxiliary and alarm switches are installed, the auxiliary switch is linked to the outputting projecting piece of the opening and closing lever, while the alarm switch is linked to the outputting projecting piece of the alarm-outputting plate.Type: GrantFiled: April 5, 2001Date of Patent: April 15, 2003Assignee: Fuji Electric Co., Ltd.Inventors: Koji Nomura, Naoshi Uchida, Katsunori Kuboyama, Tatsunori Takahashi, Kentaro Toyama
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Patent number: 6400538Abstract: An energy storage system for use in a magnetic pulse welding and forming apparatus includes a bank of capacitors and a very-low inductance conductive bus system interconnecting the capacitors. The bus system provides the ability to generate a very high frequency, short duration impulse which is needed for welding. The bus system includes first, second and third flat bus panels disposed in closely spaced overlying relation. The second, or middle, bus panel is the “hot” bus and is electrically insulated from the first (lower) and third (upper) bus panels by sheets of electrically insulating material. The first and third bus panels are connected together cooperatively form a ground bus. The bus system overlies the upper ends of the capacitors wherein the second bus panel is electrically interconnected to the respective hot contacts of the capacitors, and further wherein the ground bus is electrically interconnected with the respective ground contacts of the plurality of capacitors.Type: GrantFiled: March 3, 2000Date of Patent: June 4, 2002Assignee: INLI, LLCInventors: Ludmila Kistersky, Daniil Dudko, Viatcheslav Shevchenko, Thomas A. Barber, Jr.
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Publication number: 20010019468Abstract: An energy storage system for use in a magnetic pulse welding and forming apparatus includes a bank of capacitors and a very-low inductance conductive bus system interconnecting the capacitors. The energy storage system further includes an energy source connected to the capacitors, a discharge device, a charging control device, and a discharge control device for selectively initiating discharge of energy stored in the capacitors. The discharge device includes a central electrode placed coaxially inside a ring electrode with an adjustable concentric gap, and an ignition electrode designed as a coaxial ring surrounding the central electrode. The central electrode can be movable, i.e. either rotatable or slidable relative to the bus system. To control the direction of movement of the plasma jet, the central electrode is provided with a central air path and tangential jets opening adjacent to the ignition electrode for organizing air flow through the discharge gap.Type: ApplicationFiled: January 23, 2001Publication date: September 6, 2001Inventors: Ludmilla Kistersky, Danylo Dudko, Viacheslav Shevchenko
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Patent number: 6170973Abstract: A wide-angle illuminator for machine vision applications comprises a fiber optic bundle having a tail end defining a long narrow illumination line adjacent the workpiece and a head end defining a rectangular inlet adjacent the light source. The light source comprises a lamp located within a concave, elliptical cross-section reflector that is elongated in one direction. The elliptical cross-section is the same across the entire direction of elongation, thus defining a partial elliptical cylinder, which is preferably capped by flat, reflective surfaces at each end. The lamp, particularly the filament of the lamp, is aligned with one focus of the ellipse. The head inlet of the fiber optic bundle is aligned with the second focus of the ellipse so that the light emitted from the lamp is reflected to the second focus for transmission through the fiber optic bundle.Type: GrantFiled: November 26, 1997Date of Patent: January 9, 2001Assignee: Cognex CorporationInventor: George J. Benedict
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Patent number: 6060946Abstract: An input buffer circuit is connected to a first power supply voltage pad for applying a first power supply voltage, and a first ground line. An internal circuit larger in power consumption than the input buffer circuit is connected to a second power supply voltage pad for applying a second power supply voltage, and a second ground line. The parasitic resistance of the first ground line is higher than that of the second ground line. By connecting a capacitance between a power supply line connected to the first power supply voltage pad, and the first ground line, fluctuations in first power supply voltage are suppressed to prevent the input buffer circuit from malfunctioning.Type: GrantFiled: February 18, 1998Date of Patent: May 9, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Takayuki Harima, Kenichi Nakamura, Masami Masuda
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Patent number: 5633777Abstract: To adapt a three-electrode arrester having copper electrodes to high switching capacities (200 Amp a.c. current per discharge gap simultaneously for 11 cycles at 60 Hz), the following measures are provided: The cylindrical end electrodes have a volume of at least 60 mm.sup.3, given a ratio of length (L.sub.2) to diameter (D.sub.2) of less than 2.5; the middle electrode has the shape of a hollow cylinder with end regions of a reduced wall thickness; the middle electrode and the hollow cylindrical insulators are soldered to one another at the front ends.Type: GrantFiled: October 13, 1995Date of Patent: May 27, 1997Assignee: Siemens AktiengesellschaftInventors: Jurgen Boy, Gerhard Lange
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Patent number: 5440442Abstract: An apparatus and method for optimizing power factor in single phase and three phase installations. Capacitor circuits are interruptably connected with busses by means of switches. Leads electrically connected to the busses are attached to the load leads. The correct capacitance to optimize the power factor is determined experimentally by closing the switches, singly and in combination, until the power factor is in the 95-98% range. A power factor meter is used to determine power factor.Type: GrantFiled: March 1, 1993Date of Patent: August 8, 1995Inventor: Gregory G. Taylor
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Patent number: 5293522Abstract: A ground fault circuit breaker in which both the fixed and movable contacts of the ground fault test switch are directly secured to the printed circuit board on which the ground fault detection circuit is implemented, with the movable contact also providing the spring bias for the test button.Type: GrantFiled: September 11, 1992Date of Patent: March 8, 1994Assignee: Westinghouse Electric CompanyInventors: Joseph P. Fello, Umesh C. Patel, Michael J. Whipple, Garry B. Theadore
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Patent number: 5206775Abstract: A circuit bypass device (30) having terminals (70, 80) is connected to contacts (70, 80) of a cell (20) to provide a conductive path (40) in response to voltage excursion therebetween. Device (30) includes: a conductive shunt (40), coupled to contacts (70, 80), that is movable from a normally non-conductive position to a conductive position between terminals (70, 80); a detector (50), coupled to conductive shunt (40), for sensing voltage excursion beyond specified limits between contacts (70, 80); and an actuator (60) having a heat-to-recover shape memory metal alloy that is formed to contract when detector (50) senses the voltage excursion, for moving conductive shunt (40) from the non-conductive position to the conductive position. The formed alloy is preferably spring-shape which contracts translationally and torsionally.Type: GrantFiled: May 23, 1991Date of Patent: April 27, 1993Assignee: Space Systems/Loral, Inc.Inventor: Jean P. Wilson
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Patent number: 5181154Abstract: A circuit arrangement for current supply in processes of electrochemically initiated plasma-chemical layer production. It is preferably applied in the plasma-chemical conversion of electrochemically pre-formed layers, e.g. on light metals. The output of the adjustable three-phase transformer with subsequently connected 6-pulse rectifier circuit is branched twice, wherein a first bridge circuit comprises a capacitor connected in parallel to a voltage sensor. A second bridge circuit contains a freewheeling diode parallel to the current limiting choke and the bath for process implementation. A pulse analyzer is arranged parallel to the latter, and the two bridge circuits are separated by a switch element.Type: GrantFiled: April 1, 1992Date of Patent: January 19, 1993Assignee: Jenoptik GmbHInventors: Jens Haupt, Kirstin Haupt, Henry Hornhauer
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Patent number: 5101314Abstract: In the protection system for a capacitor bank, a resistor is connected in series between a connection cable for connecting capacitor unit groups in parallel with one another and a short-circuit device provided for each capacitor unit group, by which a first short-circuit current flowing into a damaged capacitor unit from the other capacitor unit groups in a case of a short-circuit fault in the capacitor unit can be reduced and bypassed in safety, and, consequently, secondary accidents such as a fire followed by the short-circuit fault in the capacity unit can be prevented effectively.Type: GrantFiled: June 21, 1990Date of Patent: March 31, 1992Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Satarou Yamaguchi
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Patent number: 5087999Abstract: A capacitor bank comprising a plurality of capacitor units coupled in parallel, and an energy absorbing resistor Rj is inserted in series with each one Cj of the capacitor units. Thus, when a capacitor unit Cj suffers an insulation failure, the energy flowing into the failing capacitor unit Cj from the other capacitor units is absorbed substantially by the resistor Rj. The capacitor bank may comprise several serially connected rows of parallel connected capacitor units, an energy absorbing capacitor Rij being inserted in series with each one Cij of the capacitor units. Further, each capacitor unit Cj may be provided with a protective short-circuiting device Sj, which short circuits the two terminals of the capacitor unit Cj via a bypass line 9 upon an occurance of failure of the capacitor unit Cj. An oscillation preventing resistor Ry is connected in series with each capacitor unit Cj in addition to an energy absorbing resistor Rx.Type: GrantFiled: August 28, 1990Date of Patent: February 11, 1992Assignees: Director General, Agency of Industrial Science and Technology, Mitsubishi Denki Kabushiki KaishaInventors: Yasuhiro Sato, Yoichi Hirano, Sataro Yamaguchi
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Patent number: 5065307Abstract: A built-in insulating element for electrically insulating a process portion from a control object and for transmitting a process result to the control object is provided in the output portion for transmitting the process result of a sequence controller to the control object. Further, a noise preventive element is provided in the output portion for preventing a noise voltage from coming in from the control object side and damaging the insulating element.Type: GrantFiled: August 25, 1989Date of Patent: November 12, 1991Assignee: Hitachi, Ltd.Inventors: Takayuki Oshiga, Katsuhiro Fujiwara, Kazunori Umeda
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Patent number: 5063340Abstract: A capacitive power supply having a charge equalization circuit. The charge equalization circuit is comprised of a shunt circuit connected in a parallel connection with capacitive elements of the capacitive power supply. Once a charging current is applied to the capacitive power supply to store charge thereupon to form thereby a potential difference across the capacitive elements of a pre-determined level, the shunt circuit forms a shunt to shunt the charging current thereto.Type: GrantFiled: October 25, 1990Date of Patent: November 5, 1991Assignee: Motorola, Inc.Inventor: John A. Kalenowsky
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Patent number: 4998098Abstract: An voltage monitoring system including means for providing a voltage from a current and for reducing the voltage. The system also includes means for integrating the current. The integrating means provides an output which increases from an initial condition at a rate proportional to the voltage. The system further includes means for sensing when the output of the integrating means is above a predetermined level and for resetting the integrating means to the initial condition. Additionally, the system includes means for indicating when the output of the integrating means exceeds the predetermined level.Type: GrantFiled: January 26, 1989Date of Patent: March 5, 1991Assignee: Schweitzer Engineering Laboratories Inc.Inventor: Edmund O. Schweitzer, III
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Patent number: 4975796Abstract: A device which enables a self-healing capacitor with more than one group of sections in series to undergo repetitive clearing without generating the resulting potential differences between the series sections which causes additional failures. In one embodiment, the device to conduct charge is a diode and resistor connected across each group of parallel sections so as to be nonconducting when the capacitor is charged but to become conducting when a clearing event occurs. An additional aspect of the device is a method for charging such a capacitor so that no section is overcharged.Type: GrantFiled: October 13, 1988Date of Patent: December 4, 1990Assignee: Aerovox IncorporatedInventor: Frederick W. MacDougall
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Patent number: 4956739Abstract: A device to locate internal faults in a high-voltage capacitor battery that has a plurality of symmetrically parallel and series-coupled capacitor banks arranged in parallel branches coupled by shunt branches. The phase angles of the shunt currents flowing in the shunt branches relative to the total current flowing in the parallel branches are determined. A fault is located in one of the capacitor banks based upon these determined phase angles.Type: GrantFiled: June 27, 1989Date of Patent: September 11, 1990Assignee: Siemens AktiengesellschaftInventors: Michael Becker, Klaus Renz
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Patent number: 4805063Abstract: A fault detector for detecting faults in a DC capacitor circuit connected to the DC buses of an inverter circuit using semiconductor device for converting direct current into alternating current to suppress the voltage pulsation and comprising a plurality of parallel-connected capacitor circuits each having a plurality of series-connected DC capacitors. The fault detector comprises a comparison means connected to the junctions of the series-connected DC capacitors to compare the respective potentials of the parallel-connected capacitor circuits, and detects the short-circuit and time-aging of the DC capacitors of the parallel-connected capacitor circuits rapidly on the basis of the output signal of the comparison means.Type: GrantFiled: April 21, 1987Date of Patent: February 14, 1989Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Michio Kataoka, Shigenori Higashino
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Patent number: 4750076Abstract: A geometric arrangement for filter capacitors used in high frequency power supplies such that a multiplicity of paralleled capacitors not only share the current but also provide optimum filtering. The terminals of each of the capacitors are connected by equal inductances to receive the rectified alternating current. The capacitor terminals are also connected directly to the output of the supply in order to provide the D.C. current thereto.Type: GrantFiled: April 20, 1987Date of Patent: June 7, 1988Assignee: Reliance Comm/Tec CorporationInventor: Neil Kammiller
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Patent number: 4330777Abstract: A device for detecting imminent failure of a high-dielectric stress capacitor utilizing circuitry for detecting pulse width variations and pulse magnitude variations. Inexpensive microprocessor circuitry is utilized to make numerical calculations of digital data supplied by detection circuitry for comparison of pulse width data and magnitude data to determine if preselected ranges have been exceeded, thereby indicating imminent failure of a capacitor. Detection circuitry may be incorporated in transmission lines, pulse power circuitry, including laser pulse circuitry or any circuitry where capacitors or capactior banks are utilized.Type: GrantFiled: November 5, 1980Date of Patent: May 18, 1982Assignee: The United States of America as represented by the United States Department of EnergyInventor: George G. McDuff
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Patent number: 4329638Abstract: The present invention refers to capacitive voltage transformers.In accordance with one embodiment a capacitive voltage transformer has two capacitors connected in series between a point on a high voltage line and a reference point such as earth and two impedances connected in series with the two capacitors.A medium voltage electromagnetic detector is connected between the common point of the two capacitors and the common point of the two impedances. An electronic voltage detector is connected to the terminals of the series circuit formed by the two impedances, the values of the latter being selected in order that the instantaneous voltage at the terminals of the electronic detector is always a constant fraction of the voltage taken off between the line and the reference point.Application to the operation of highspeed static protections from a capacitive voltage transformer having a medium voltage electromagnetic circuit.Type: GrantFiled: September 23, 1980Date of Patent: May 11, 1982Assignee: EnertecInventor: Daniel Le Maguet
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Patent number: 4326230Abstract: A circuit for monitoring the voltage stress of a capacitor which produces an over-stress indicator signal responsive to the over-voltage history of the capacitor. If the measured voltage stress of the capacitor exceeds a predetermined over-voltage value, a characteristic-curve generator, having a predetermined transfer function, produces an output signal which is responsive to the measured voltage stress of the capacitor and the transfer function of the characteristic-curve generator. This signal is combined with a further signal which is responsive to a predetermined permissible continuous operation voltage value. The combined signals are conducted to an integrator having a predetermined integration time constant for producing an overload signal. The overload signal at the output of the integrator is a measure of the state of stress of the capacitor. Circuitry may be provided for disconnecting the capacitor from a transmission line in response to the output signal of the integrator.Type: GrantFiled: July 3, 1980Date of Patent: April 20, 1982Assignee: Siemens AktiengesellschaftInventors: Michael Becker, Klaus Renz, Manfred Weibelzahl, Alfons Fendt, Dusan Povh, Gerhard Schuch, Hermann Waldmann
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Patent number: 4322766Abstract: A circuit for monitoring the capacitor battery of a filter circuit connected to a transmission line, the capacitor battery consisting of at least two parallel legs, each with a number of series-connected capacitors. A first signal is produced which corresponds to the total alternating current flowing through the capacitor battery. A second signal is produced which corresponds to the difference between the currents flowing through the respective parallel legs of the capacitor battery. The current difference signal is compared with a respective fraction of the total current signal. A fault indicator signal is produced if the difference between the difference current signal and the fractional total current signal exceeds a predetermined threshold value. Further circuitry is provided for correcting drift in the difference current signal, which may be caused by temperature variations or acceptable capacitor failures.Type: GrantFiled: July 3, 1980Date of Patent: March 30, 1982Assignee: Siemens AktiengesellschaftInventors: Michael Becker, Klaus Renz, Manfred Weibelzahl
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Patent number: 4295174Abstract: A multi-series group capacitor bank has voltage limiters, of the metal oxide type, connected across each individual series group and set at a protection level higher than that of the bank bypass spark gap so the voltage limiters bypass a series group when capacitor fuse clearing causes high voltage build-up in that series group.Type: GrantFiled: May 29, 1979Date of Patent: October 13, 1981Assignee: Westinghouse Electric Corp.Inventors: Charles A. Peterson, Louis C. Grove, Jr.
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Patent number: 4219856Abstract: A protective device for a capacitor bank is coupled to a cross-connection between equipotential points in two sub-banks forming the bank. Current or voltage surges, indicative of a capacitor failure are counted and when a threshold level is exceeded, an alarm may be energized.Type: GrantFiled: March 2, 1978Date of Patent: August 26, 1980Assignee: ASEA AktiebolagInventors: Per Danfors, Nils Fahlen, Owe Nerf
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Patent number: 4104687Abstract: A sensing device is connected to an intermediate tap point on each phase leg of a polyphase system such as a grounded wye-connected capacitor bank to detect faulted capacitor units and thereby control a switching device to isolate the capacitor bank. The intermediate tap point is selected in each phase leg such that the number of series units (such as parallel capacitor groups) above the tap point equals (or exceeds by one) the number of series units below the tap point. The outputs of these sensing devices are coupled through a calibration network to a summing amplifier which operates to add the three signals vectorily to produce on AC output signal that is filtered by a 60 Hz band pass filter to attenuate unwanted harmonics and noise which might introduce error into the measurement. Initial balance is achieved by adjusting the magnitude of each phase to ground signal to equalize those signals from each of the intermediate tap points.Type: GrantFiled: November 24, 1976Date of Patent: August 1, 1978Assignee: S&C Electric CompanyInventor: John A. Zulaski