Transformer (e.g., Split Core Admits Conductor Carrying Unknown Current) Patents (Class 324/127)
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Patent number: 7746056Abstract: An electronic circuit includes a substrate having a surface and a device supported by the surface of the substrate. The electronic circuit also includes a magnetic field transducer disposed over the surface of the substrate and an insulating layer disposed between the substrate and the magnetic field transducer. The electronic circuit also includes a conductor disposed over the magnetic field transducer. The conductor is configured to carry an electrical current to generate a first magnetic field. The electronic circuit is responsive to the first magnetic field.Type: GrantFiled: January 22, 2009Date of Patent: June 29, 2010Assignee: Allegro Microsystems, Inc.Inventors: Jason Stauth, Richard Dickinson, Glenn Forrest, Ravi Vig
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Publication number: 20100156393Abstract: A current sensor includes a coil for sensing current in a current carrying bus, and a mount for mounting the coil to the current carrying bus at a distance from the bus. A system including the current sensor includes similar structure.Type: ApplicationFiled: December 18, 2008Publication date: June 24, 2010Applicant: GENERAL ELECTRIC COMPANYInventor: Brian Eric Lindholm
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Patent number: 7733094Abstract: An apparatus for monitoring and measuring the electrical, thermal and mechanical operating parameters of high voltage power conductors. A toroidal shaped housing, which can be mounted onto an energized conductor, contains all of the necessary electrical instruments to monitor the parameters associated with the conductor. Moreover, the housing includes the processing capability to analyze disturbance and fault events based on these parameters.Type: GrantFiled: October 31, 2005Date of Patent: June 8, 2010Assignee: Underground Systems, Inc.Inventors: James Bright, Larry Fish, John Engelhardt, Paul Alex, Duncan Breese
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Patent number: 7733080Abstract: The clamp meter contains a revolving member configured between the meter's body member and jaw member. The revolving member is composed of a first base and a second base located on the interfacing sides of the body member and the jaw member, respectively. The first base and the second base are revolvably joined together by an axle extended axially from the body member into the jaw member via the first and second bases' aligned axle holes. The first base has at least a roller ball elastically embedded in a concave and exposed towards the second base. The roller ball would roll into one of a number of notches of the second base as the base and jaw members are rotated relative to each other, thereby creating a number of preset configurations of the included angle between the body and jaw members.Type: GrantFiled: November 20, 2008Date of Patent: June 8, 2010Assignee: Chung Instrument Electronics Industrial Co., Ltd.Inventor: Shaw-Lin Liu
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Patent number: 7728578Abstract: In order to extend the measurement range of a current sensor, a current divider is formed by a first conductor formed in a current sensor that is mounted on a printed circuit board and a second conductor on the printed circuit board that electrically shorts at least one input terminal of the current sensor to at least one output terminal of the current sensor. The input terminal of the current sensor supplies the current to be measured to the first conductor and the output terminal supplies the measured current back to the printed circuit board.Type: GrantFiled: May 15, 2008Date of Patent: June 1, 2010Assignee: Silicon Laboratories Inc.Inventors: Brett E. Etter, Donald E. Alfano, Timothy J. Dupuis, Donald K. Coffey
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Publication number: 20100123454Abstract: The clamp meter contains a revolving member configured between the meter's body member and jaw member. The revolving member is composed of a first base and a second base located on the interfacing sides of the body member and the jaw member, respectively. The first base and the second base are revolvably joined together by an axle extended axially from the body member into the jaw member via the first and second bases' aligned axle holes. The first base has at least a roller ball elastically embedded in a concave and exposed towards the second base. The roller ball would roll into one of a number of notches of the second base as the base and jaw members are rotated relative to each other, thereby creating a number of preset configurations of the included angle between the body and jaw members.Type: ApplicationFiled: November 20, 2008Publication date: May 20, 2010Inventor: SHAW-LIN LIU
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Patent number: 7710104Abstract: A load measuring circuit including a cable including first and second conductors and a shielding. The conductors are connected by a first end thereof to a load, the shielding is not connected to a ground at the end, and the conductors are connected to a generator by the second end thereof. A transformer includes a first winding connected to a conductor on the second end of the cable, a second winding is connected between a ground and the shielding on the second end of the cable, and a third winding is connected to a current measuring member.Type: GrantFiled: October 19, 2006Date of Patent: May 4, 2010Assignee: Renault s.a.s.Inventors: Andre Agneray, Clement Nouvel
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Patent number: 7701197Abstract: An electrical current sensing assembly comprises: a conductive input substrate with a generally planar contact surface; a conductive output substrate with a generally planar contact surface proximate and substantially parallel to the input substrate contact surface; a conductive current sense path extending from the input substrate contact surface to the output substrate contact surface with a sense path cross sectional area generally normal to electrical current flow; a conductive current bypass path extending from the input substrate contact surface to the output substrate contact surface with a bypass path cross sectional area generally normal to electrical current flow; and an electrical current sensing device proximate the current sense path for sensing electrical current passing through the current sense path; wherein the ratio of the current passing through the bypass path to the current passing through the sense path is proportional to the ratio of the bypass path cross sectional area to the sensing pType: GrantFiled: April 20, 2008Date of Patent: April 20, 2010Assignee: Hamilton Sundstrand CorporationInventors: Randal Sherman, Shin Katsumata
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Patent number: 7696743Abstract: In a zero-phase current detecting apparatus, a feedback loop is made up of a pulse generating unit, a current detecting unit, a peak detecting unit, an adding unit, and a current regulating unit. The adding unit outputs a difference between a target value and a peak value detected by the peak detecting unit. A zero-phase current is detected based on the difference output from the adding unit as a result of regulation of the peak value so as to be the target value in the adding unit.Type: GrantFiled: August 31, 2006Date of Patent: April 13, 2010Assignee: Mitsubishi Electric CorporationInventors: Daisuke Tajima, Hirokazu Nakabayashi, Naoki Nishio
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Publication number: 20100085782Abstract: A resonant converter comprises switching circuitry (1) for supplying pulses, at a controllable frequency, to a resonant circuit so as to power the primary circuit (3, 12) of a transformer (4). The secondary winding (5a, 5b) of the transformer (4) delivers an AC signal which is rectified and then produces a load current. On the primary side, the converter has a resistor (13) for deriving a first electrical signal representative of the current in the primary circuit (3, 12), and an auxiliary winding (14) which is closely coupled to the secondary winding (5a, 5b) and across which an auxiliary voltage is induced as a consequence of the close coupling of the winding (14) to the secondary winding (5a, 5b). A resistor/capacitor combination (16, 17) integrates the auxiliary voltage with respect to time to derive a second electrical signal.Type: ApplicationFiled: February 25, 2008Publication date: April 8, 2010Applicant: NXP, B.V.Inventor: Hans Halberstadt
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Publication number: 20100085036Abstract: A power line monitoring device is mounted to a power line. The device includes circuitry for monitoring the power line and communicating information regarding the power line. A ground reference point of the circuitry is electrically coupled to the power line. Therefore, the monitoring device, including its circuitry, has substantially the same voltage potential as the power line. Accordingly, there is a substantially equalized or uniform electric field around the device. The substantially equal voltage potential and electric field allow communications with the monitoring device to have reduced noise and interference, as compared to other devices that have different voltage potentials than their corresponding power lines. A pad of semi-conductive material may be disposed between the power line and the electrical conductors to slow a rate of change of the voltage potential of the device circuitry when mounting the device to the power line, thereby minimizing risk of corona discharge.Type: ApplicationFiled: September 29, 2009Publication date: April 8, 2010Applicant: Cooper Technologies CompanyInventors: John Fredrick Banting, Gregg James Haensgen, Bruce W. McBee
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Publication number: 20100060261Abstract: The coupling device with electrical isolation comprises at least one input signal, an output of an output signal representative of said input signal, and signal transfer means with electrical isolation receiving the input signal and supplying said output signal. The transfer means comprise at least one signal transformer having at least one primary winding to receive a primary signal representative of said input signal, switching means to switch the input signal and supply the latter to said primary winding, and electrically isolated control means of the switching means comprising a control input receiving control signals during switching periods. The electrical switchgear unit comprises one such coupling device connected to measuring resistors and to a processing unit processing electrical protection functions.Type: ApplicationFiled: December 10, 2007Publication date: March 11, 2010Applicant: Schneider Electric Industries SASInventors: Yvan Cadoux, Didier Leonard, Bruno Reymond
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Patent number: 7671580Abstract: An integrated current sensing transformer includes a bobbin, a magnetic core assembly, a first primary winding element, a second primary winding element, a secondary winding element. The bobbin has a receptacle therein. The magnetic core assembly is partially embedded into the receptacle for providing a closed path of magnetic flux. The first primary winding element is wound around the bobbin for inputting a first test current therein. The second primary winding element is wound around the bobbin for inputting a second test current therein. The secondary winding element is wound around the bobbin for outputting a sensing current when either the first test current or the second test current is sensed. The magnitude of the sensing current is directly proportional to the magnitude of the first test current or the second test current.Type: GrantFiled: November 30, 2006Date of Patent: March 2, 2010Assignee: Delta Electronics, Inc.Inventor: Wen-Kuan Hsu
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Publication number: 20100045263Abstract: The current measurement device with electrical isolation comprises an input signal connected to an electrical shunt, an output of an output signal, and signal transfer means with electrical isolation receiving the input signal and supplying said output signal. The transfer means comprise at least one signal transformer having at least one primary winding to receive a primary signal representative of said input signal, switching means to switch the input signal and supply the latter to said primary winding, and electrically isolated control means of the switching means comprising a control input receiving control signals during switching periods. A trip unit and an electrical circuit breaker comprises one such current measurement device and a processing unit processing electrical protection functions.Type: ApplicationFiled: December 10, 2007Publication date: February 25, 2010Applicant: SCHNEIDER ELECTRIC INDUSTRIES SASInventors: Yvan Cadoux, Didier Leonard, Bruno Reymond
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Patent number: 7667452Abstract: Detector circuit for measuring relatively strong currents including a main current transformer (1) and two substantially identical auxiliary current transformers (2, 3) where a main current (I1) induces magnetomotive forces in said main current transformer (1), said magnetomotive forces being counteracted by magnetomotive forces induced by a compensating current (i1) while at the same time the two auxiliary transformers (2, 3) are magnetised in antiphase by means of a square wave/modulation signal. Furthermore the detector circuit includes a synchronous rectifier for generating an adjusting signal for the compensating current (i1). According to the invention a compensating current is used for measuring current in a common winding (L3) surrounding the main transformer as well as the auxiliary transformers while at the same time a possible error signal in the shape of a voltage difference between the auxiliary transformers is used to adjust the compensating current (i1) by means of a negative feedback loop.Type: GrantFiled: November 4, 2005Date of Patent: February 23, 2010Assignee: Liaisons Electroniques-Mecaniques LEM S.A.Inventor: Andreas Marcussen
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Patent number: 7663459Abstract: A short-circuit indicator is provided for arrangement on an electrical line for electrical power distribution which includes a current transformer. The current transformer has an induction coil and an iron yoke for surrounding the electrical line to be monitored for a short-circuit current. The induction coil is seated on a base web of a U-shaped first yoke part. A second yoke part is connected in the form of a joint which can move between a closed position and an open position to one of two U-limbs of the first yoke part. The second yoke part forms a magnetic return path element for the first yoke part in the closed position. The first yoke part is split into two essentially L-shaped parts in the area of the base web to which the induction coil is fitted.Type: GrantFiled: June 23, 2008Date of Patent: February 16, 2010Assignee: Dipl.-Ing. H. Horstmann GmbHInventor: Hendrik Horstmann
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Publication number: 20100033165Abstract: A device for measuring currents induced in a CAN bus harness. In some embodiments, the device includes a first termination node, a second termination node, a current separator, a detection circuit, and a power source circuit. The current separator circuit has an RF transformer connected to the first termination node and separates a common mode RF current and a differential mode RF current of an RF current signal. The detection circuit is connected to the current separator circuit and receives at least one of the common mode RF current and the differential mode RF current from the separator circuit. The detection circuit also converts the common mode RF current and differential mode RF current to an non-RF output signal. The power source circuit provides power to the detection circuit.Type: ApplicationFiled: August 6, 2008Publication date: February 11, 2010Applicant: Robert Bosch GmbHInventors: Cyrous Rostamzadeh, Sergio A. Pignari
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Patent number: 7659709Abstract: An electric current sensor having a housing, magnetic circuit with a magnetic core, and a magnetic field detector with a detection cell, positioned in an air gap between ends of the core. The core is made of a non-laminated magnetic material, and the magnetic circuit has a strap made of non-magnetic material welded to the core at each side of the air gap. The magnetic field detector has a support plate on which the detection cell is mounted. The plate has a recess, opposition the detection cell, which houses one end of the magnetic circuit.Type: GrantFiled: November 14, 2007Date of Patent: February 9, 2010Assignee: Liaisons Electroniques-Mécaniques LEM S.A.Inventors: Gerard Lepine, Olivier De Loriol, Gilles Moret, Thierry Chenavard
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Patent number: 7659710Abstract: A current clamp meter having a current meter body and a detachable current clamp. The current meter body and the current clamp are configured so that the current clamp is detachable from the current meter body and the meter is operable with the current clamp either attached to the current meter body or detached from the current meter body.Type: GrantFiled: October 20, 2008Date of Patent: February 9, 2010Assignee: Fluke CorporationInventors: Shounan Luo, Wang Yong
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Patent number: 7656266Abstract: A toroidal power transformer is disclosed. The toroidal power transformer comprises a circular core composed of plurality of laminated electrically conductive materials, a plurality of multi-layered first windings radially wound around the circular core, said winding arranged with an angular spacing of 2? and a number of windings in each winding layer is less than a number of windings in each previous layer, a multi-layered second winding radially wound around the circular core covering a corresponding one of said plurality of first windings, wherein the layers of each of said second windings are arranged to form a substantially triangular cross-section; and an insulating layer between each of said first and second windings.Type: GrantFiled: January 9, 2008Date of Patent: February 2, 2010Inventor: Kern K. N. Chang
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Patent number: 7656149Abstract: A current transformer detects a sine-wave alternating current having a maximum effective current value Imax(Arms) and a frequency f(Hz) and a half-sine-wave rectified current having a maximum peak value Ipeak(Aop) and a frequency f(Hz) in a primary winding, consisting of at least one magnetic core with one turn of primary winding and at least one multiple turns of secondary winding to which a detecting resistor is connected.Type: GrantFiled: August 13, 2008Date of Patent: February 2, 2010Assignee: Metglas, Inc.Inventor: Shin Nakajima
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Publication number: 20100020457Abstract: Relay devices, systems and methods for obtaining an accurate representation of a current monitored with a Rogowski coil, without integration of the Rogowski coil output voltage signal in the time domain.Type: ApplicationFiled: September 24, 2009Publication date: January 28, 2010Applicant: COOPER TECHNOLOGIES COMPANYInventors: Ljubomir A. Kojovic, Stephen E. Williams
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Publication number: 20100013460Abstract: A Rogowski sensor is provided for measuring a current of an electrical conductor. The sensor has a Rogowski coil, which has an electrical winding resistor, and an integration device which is connected to the Rogowski coil and is intended to generate an output signal which is proportional to the electrical current to be measured by the Rogowski sensor. The integration device is formed by the winding resistor of the Rogowski coil and a capacitance which is connected to the two winding connections of the Rogowski coil, and for the output signal from the integration device to be formed by the voltage applied to the capacitance.Type: ApplicationFiled: December 12, 2007Publication date: January 21, 2010Applicant: SIEMENS AKTIENGESELLSCHAFTInventors: Jochen Ermisch, Uwe Hering, Frank Thieme, Ralf-Reiner Volkmar
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Publication number: 20100007336Abstract: There is disclosed a method of monitoring an electrical network of the type having a feeder line connected to a plurality of distribution transformers, each distribution transformer being in turn coupled to a load which may be provided with a customer meter. The method includes the steps of recording an accumulated in-phase current at each of the distribution transformers over a time period and recording for the same time period an accumulated in-phase current at the feeder line. The sum of the accumulated in-phase currents recorded at the distribution transformers are then compared to the accumulated in-phase current recorded at the feeder line. The method may also include the steps of recording accumulated in-phase currents at the customer meters and comparing their sum with the accumulated in-phase current measured at the distribution transformers coupled to the customer meters.Type: ApplicationFiled: January 12, 2009Publication date: January 14, 2010Inventor: Eric George de Buda
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Patent number: 7642768Abstract: A current sensor includes a magnetic field sensing element, a first conductor including sandwich structure and second conductor including sandwich structure electrically coupled to one another. The magnetic field sensing element is interposed between the first and second sandwich structure. The magnetic field sensing element is operable to receive magnetic flux lines resulting from current flowing through the first and second conductor sandwich structure. The first and second conductor sandwich structure each include a top portion including at least a first electrical conductor, a bottom portion including at least a second electrical conductor, and a layer of magnetic permeable material different from the first and second electrical conductor interposed between the top portion and bottom portion.Type: GrantFiled: October 21, 2008Date of Patent: January 5, 2010Assignee: Honeywell International Inc.Inventor: Helmut Kinzel
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Patent number: 7638999Abstract: Relay devices, systems and methods for obtaining an accurate representation of a current monitored with a Rogowski coil, without integration of the Rogowski coil output voltage signal in the time domain.Type: GrantFiled: April 7, 2006Date of Patent: December 29, 2009Assignee: Cooper Technologies CompanyInventors: Ljubomir A. Kojovic, Stephen E. Williams
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Patent number: 7633287Abstract: A core is divided by alternately arranging plural magnetic material portions and plural non-magnetic material portions in a circumferential direction of the core through which a primary conductor penetrates. A conductor is wound around the core under conditions in which each core cross section of the core intersects the magnetic material portion and the non-magnetic material portion, each core cross section including a cut end surface of each conductor of a secondary winding wound around the core, and a ratio of a magnetic material portion cross-sectional area of the magnetic material portion to a non-magnetic material portion cross-sectional area of the non-magnetic material portion at the core cross section is kept constant at each core cross section.Type: GrantFiled: October 22, 2008Date of Patent: December 15, 2009Assignee: Mitsubishi Electric CorporationInventors: Ryuichi Nishiura, Yo Makita, Hiroshi Nishizawa, Tadahiro Yoshida, Tae Hyun Kim
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Publication number: 20090289618Abstract: In a zero-phase current detecting apparatus, a feedback loop is made up of a pulse generating unit, a current detecting unit, a peak detecting unit, an adding unit, and a current regulating unit. The adding unit outputs a difference between a target value and a peak value detected by the peak detecting unit. A zero-phase current is detected based on the difference output from the adding unit as a result of regulation of the peak value so as to be the target value in the adding unit.Type: ApplicationFiled: August 31, 2006Publication date: November 26, 2009Applicant: Mitsubishi Electric CorporationInventors: Daisuke Tajima, Hirokazu Nakabayashi, Naoki Nishio
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Patent number: 7622910Abstract: Integrated current sensors are used in AC electric power systems. An integrated current sensor according to one embodiment comprises: an inductor (101), wherein an AC current passes through the inductor (101); an integrator circuit (103), the integrator circuit (103) receiving a voltage associated with the AC current; a gain control circuit (116) operationally connected to the integrator circuit (103), the gain control circuit (116) outputting a gain controlled signal; and a compensation circuit (115) operationally connected to at least two of the integrator circuit (103), the gain control circuit (116), and the inductor (101), to compensate for parameter variation induced in the gain controlled signal or in the output of the integrator circuit (103).Type: GrantFiled: March 12, 2007Date of Patent: November 24, 2009Assignee: Honeywell International Inc.Inventor: Hassan Ali Kojori
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Patent number: 7615988Abstract: A current measurement technique is disclosed in which a family of transformer coils having the same number of turns and the same winding resistance may be associated an active circuit for presenting a burden resistance of substantially zero value. The impedance of the coils will vary with their window size, and the active circuitry will reduce the burden resistance accordingly so that reductions and impedance do not result in introducing additional error into measurements. The circuitry may be used for measuring current in single conductors or in multiple conductors passing through the transformer coil, such as for ground fault measurement, monitoring and control.Type: GrantFiled: February 12, 2007Date of Patent: November 10, 2009Assignee: Rockwell Automation Technologies, Inc.Inventor: John Herman Blakely
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Patent number: 7615989Abstract: Integrated current sensors are used in DC electric power systems. An integrated current sensor (200B) according to one embodiment comprises: a DC inductor (111B) including a resistive component and an inductive component, wherein a DC current passes through the DC inductor (111B); an integrator circuit (161), the integrator circuit (161) receiving a voltage associated with the DC inductor (111B); and a feedback system operationally connected to the DC inductor (111B) and to the integrator circuit (161), to subtract a voltage associated with the resistive component and obtain a voltage associated with the inductive component.Type: GrantFiled: March 12, 2007Date of Patent: November 10, 2009Assignee: Honeywell International Inc.Inventor: Hassan Ali Kojori
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Patent number: 7598724Abstract: A current transformer assembly includes at least one Rogowski coil having a first closeable loop with an electrically conductive coil member and a first pair of terminals. An integrator unit has respectively a cable connected across the first pair of terminals of a respective Rogowski coil. Each respective Rogowski coil provides an output voltage received by the integrator assembly caused by when a respective electrical conductor on a phase of a multiphase circuit is arranged within an opening of the closeable first loop of the respective Rogowski coil, and provides an output signal proportional to a current in a conductor arranged in an opening of a Rogowski coil. At least one of the Rogowski coils includes an inline calibration unit for fast calibration and recalibration when retrofitting a monitor module that monitors a value of the current in one or more conductors.Type: GrantFiled: January 17, 2008Date of Patent: October 6, 2009Assignee: Admmicro Properties, LLCInventors: Donald W. Howell, Samuel A. Taylor, Danny K. Dyess, Frank O. Blevins, Mark W. Vinson
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Publication number: 20090219009Abstract: A current measurement device is disclosed that is configured to measure electrical current, both AC and DC, in a primary conductor that is electrically insulated from the current measuring device. Unlike known current measuring devices, the current measuring device in accordance with the present invention does not utilize a Hall effect device and is more accurate and less expensive than current measuring devices employing such Hall effect devices. The current measuring device in accordance with the present invention includes a transformer with a saturable magnetic core formed with a central aperture and a current measuring circuit. In one embodiment of the invention, the transformer is provided with a secondary winding and no primary winding. The electrical conductor, i.e. primary conductor, in which electrical current is to be measured is disposed in the central aperture of the magnetic core and thus acts as a primary winding having a single turn.Type: ApplicationFiled: February 28, 2008Publication date: September 3, 2009Inventors: Arian M. Jansen, Huian Dong
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Patent number: 7583075Abstract: The present invention is a subtractive current measuring system for a power receptacle. The system may comprise one or more of the following features: (a) a power receptacle; (b) a current carrying input wire; (c) a current carrying output wire; (d) a current transformer; (e) an electrical measuring device; and (f) interconnecting circuitry linking the current transformer and the electrical measuring device.Type: GrantFiled: December 5, 2006Date of Patent: September 1, 2009Assignees: Geist Manufacturing, Inc., Aphel, Ltd.Inventor: Hugh G. Hutchison
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Patent number: 7570045Abstract: The present invention is an attachment device and a method for fastening and removing an electrical cable monitoring instrument to an electrical cable. The attachment device comprises monitoring instrument sensor with opening for positioning electrical cable such that said electrical cable can be positioned to pass through the sensitive volume at least partially surrounded by said sensor, at least one elongated elastic member securely attached to said cable monitoring instrument such that, when elastically deformed to a shape characterized by high mechanical energy such that deformed elastic member allows said electrical cable access to and from the sensitive volume at least partially surrounded by said monitoring instruments sensor.Type: GrantFiled: October 12, 2006Date of Patent: August 4, 2009Assignee: James G. Biddle CompanyInventors: Gregory Robert Wolfe, William Eakins Ferguson, Jr., Andrew Paul Sagl, Jeffrey Lyn Stitt
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Patent number: 7557563Abstract: A sensor apparatus for measuring power parameters on a power conductor, such as a high voltage transmission line may include a corona structure, an electronics assembly and a conductor mountable device. The corona structure may define an outer boundary surrounding the electronics assembly and the conductor mountable device. The corona structure may shield the electronic assembly and conductor mountable device from a corona produceable with the power conductor. The conductor mountable device may be a power parameter measurement device, such as a current sensor assembly. The current sensor assembly may be a split-core design that includes multiple transformer cores. The electronics assembly and the conductor mountable device may powered from a line voltage suppliable on the power conductor. Data may be wirelessly transmitted and received with the sensor apparatus.Type: GrantFiled: January 19, 2006Date of Patent: July 7, 2009Assignee: Power Measurement Ltd.Inventors: Colin N. Gunn, Stewart J. Harding, Marc A. Ricci, Daniel N. Loewen, Peter C. Cowan, Martin A. Hancock
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Patent number: 7545138Abstract: A current measurement device using a Rogowski coil having a generally toroidally shaped core with flattened faces, a first winding in one direction, a second winding forming a return loop, and a temperature compensation and scaling network coupled to the coil. The core has concentric cavities and a rough surface to restrain movement of the coil winding. A Faraday shield is wrapped over the coil. One shield is “serpentine,” having staggered (offset) lateral extensions from a central region. An alternate shield has a generally circular central region with extensions in generally radial directions. The shield is formed of three layers comprising a non-ferromagnetic metal central layer surrounded by insulative layers. At an end tab of the shield, the metal layer is exposed for connection to a ground lug or other connector. An insulative housing envelops the coil and electrical network. An output wire terminates in an industrial connector. A resistive network may be implemented with the current measurement device.Type: GrantFiled: July 6, 2006Date of Patent: June 9, 2009Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Donovan E. Wilkerson, Veselin Skendzic, James R Kesler
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Patent number: 7541800Abstract: Methods and systems for an electrical meter are provided. The meter includes a current sensor configured to be communicatively coupled to a conductor, and a processor communicatively coupled to the current sensor wherein the processor is configured to receive signals indicative of current flow through the conductor and wherein the processor is further configured to process the signals to determine an imbalance between the positive half cycle of the current flowing through the conductor and the negative half cycle of the current flowing through the conductor to detect a DC influence on the current sensor.Type: GrantFiled: July 16, 2007Date of Patent: June 2, 2009Assignee: General Electric CompanyInventors: Robert Edward Lee, Jr., Donald Frank Bullock
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Patent number: 7538541Abstract: A split Rogowski coil assembly having distinct coil loops formed on printed circuit boards that are not joined to one another.Type: GrantFiled: November 6, 2006Date of Patent: May 26, 2009Assignee: Cooper Technologies CompanyInventor: Ljubomir A. Kojovic
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Patent number: 7532001Abstract: Provided is a Q-boosting circuit for improving a Q factor in a radio frequency (RF) integrated circuit of a semiconductor device using a transformer instead of an inductor. The Q-boosting circuit couples a negative resistance circuit to a pair of terminals of a transformer to reduce a resistance component of the transformer, thereby increasing a mutual inductance component. Therefore, it is possible to obtain a more improved Q factor than a conventional Q factor through adjustment of an inductance and a resistance component, and to obtain the Q factor having a wide range from several tens to several hundreds according to a frequency range.Type: GrantFiled: June 6, 2006Date of Patent: May 12, 2009Assignee: Electronics and Telecommunications Research InstituteInventors: Young Jae Lee, Hyun Kyu Yu
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Publication number: 20090115400Abstract: The sensitivity and accuracy of a status indicator for sensing a current in an electrical circuit is improved by shifting the reference level of the transformer output to maximize the input signal to a precision voltage detector and by reducing the hysteresis of the status indicator by balancing the burden of the current transformer during the positive and negative alternations of the AC signal and by driving secondary loads with a voltage to current converter.Type: ApplicationFiled: August 13, 2008Publication date: May 7, 2009Inventor: Phillip Hunter
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Publication number: 20090115403Abstract: The size of a status indicator for monitoring a current in a power cable is reduced by integrating a bobbin for the secondary winding with a current transformer core and integrating a circuit board including output terminals with a current transformer assembly.Type: ApplicationFiled: August 13, 2008Publication date: May 7, 2009Inventor: James Bernklau
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Patent number: 7528594Abstract: The present invention is related to a device (1) for the detection of direct and/or alternating current to be used in the realization of highly sensitive amperometric measuring instruments or for the detection of differential faults along with automatic switches. The inventive device comprises a magnetic core (5) disposed in such a manner to surround at least one current-carrying conductor (6). A winding (10) surrounds the magnetic core (5) and is electrically connected to an electrical resistance (60). A voltage source (40) generates a drive voltage (Vexcit) which permits the circulation of a pick-up current (Iexcit) in the said winding (10) and in the said core (5). Amplification means (20) are used to detect the voltage (Vsense) at the terminals of the resistance (60) in order to generate a first signal (Vamp1) which is representative of the above defined current (Iexcit).Type: GrantFiled: June 21, 2005Date of Patent: May 5, 2009Assignee: ABB S.p.A.Inventors: Romano Manzoli, Francesco Viaro
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Patent number: 7525297Abstract: An impedance-compensated current transformer comprising a primary winding, a power source electrically coupled through the primary winding; a secondary winding magnetically coupled to the first primary winding, the secondary winding having a secondary winding impedance and a secondary winding resistance; and an impedance-compensation circuit electrically coupled across the secondary winding; wherein the impedance-compensation circuit actively reflects to the secondary winding a virtual impedance which is equal in magnitude and opposite in polarity to the secondary winding impedance.Type: GrantFiled: December 1, 2005Date of Patent: April 28, 2009Assignee: FALCO Ltd.Inventor: Umberto Gibellini
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Patent number: 7518354Abstract: An electronic circuit includes a first substrate having a first substrate surface and a device supported by the first substrate surface. The device is selected from among a passive electronic component and an active electronic component. The electronic circuit also includes a second substrate having a second substrate surface and a conductor proximate to the second substrate. The electronic circuit also includes a magnetic field transducer disposed over the conductor and coupled to the device and an insulating layer disposed between the conductor and the second substrate. The conductor is adapted to carry an electrical current to generate a first magnetic field. The electronic circuit is responsive to the first magnetic field. In some embodiments, the conductor is a secondary conductor and the circuit further includes a primary conductor disposed proximate to the magnetic field transducer and an insulating layer disposed between the primary conductor and the second substrate.Type: GrantFiled: June 25, 2007Date of Patent: April 14, 2009Assignee: Allegro Microsystems, Inc.Inventors: Jason Stauth, Richard Dickinson, Glenn Forrest, Ravi Vig
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Patent number: 7518529Abstract: A monitoring device (1) for monitoring the electrical properties of a medium voltage overhead line (3) in a medium voltage network comprises three separate measurement sensors (2a, 2b, 2c), each being adapted for direct connection onto a medium voltage overhead line. Each of the measurement sensors has means to draw operating power from the medium voltage overhead line. The measurement sensors measured results may be combined for accurate measurement analysis.Type: GrantFiled: January 31, 2003Date of Patent: April 14, 2009Assignee: FMC Tech LimitedInventors: Charles Brendan O'Sullivan, Michael Martin Quinlan
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Publication number: 20090072813Abstract: An intelligent electronic device (IED), e.g., an electrical power meter, having circuitry for reducing the burden placed on at least one current sensor of the device resulting in a highly accurate measurement by the at least one current sensor is provided. The circuitry of the present disclosure reduces the burden on the current sensor while providing amplification, e.g., gain control, to the input signal. The circuitry includes at least one current sensor outputting a signal to an operational amplifier (op amp) having a controlled variable feedback resistance. By employing an operational amplifier in the circuitry, the output of the current sensor will be at a near zero volts condition at all times thus reducing the burden on the current sensor.Type: ApplicationFiled: September 16, 2008Publication date: March 19, 2009Applicant: Electro Industries/Gauge Tech.Inventor: Tibor Banhegyesi
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Publication number: 20090066317Abstract: The present invention is a meter for recording voltage and current on a transformer. The device has a housing with a body portion and a lever portion, the lever portion being movable between a closed position wherein the lever portion abuts the body portion and an open position wherein the lever portion is positioned away from the body portion. The device includes a pair of current sensors each current sensor being divided into two corresponding sensor fractions with one fraction of each sensor formed on the body portion of the housing and the other corresponding fraction formed on the lever portion of the housing. The fractions of each sensors are constructed such that each of the current sensors have a central opening dimensioned to receive one of the transformer terminals when the lever portion of the housing is in its first position. The current sensors are positioned on the housing such that the meter can be mounted to the terminals of the transformer.Type: ApplicationFiled: July 11, 2008Publication date: March 12, 2009Inventor: Eric de Buda
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Publication number: 20090058399Abstract: A method of manufacturing a clamp jaw assembly for a clamp meter is provided. The method includes providing a clamp jaw core and a shield having a channel. The method further includes positioning the clamp jaw core within the channel of the shield such that the shield surrounds a portion of the clamp jaw core. The method also includes enclosing the clamp jaw core and the shield within a clamp jaw housing.Type: ApplicationFiled: August 30, 2007Publication date: March 5, 2009Applicant: FLUKE CORPORATIONInventors: Yong Wang, Yinhong Yang
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Publication number: 20090039870Abstract: A current clamp meter having a current meter body and a detachable current clamp. The current meter body and the current clamp are configured so that the current clamp is detachable from the current meter body and the meter is operable with the current clamp either attached to the current meter body or detached from the current meter body.Type: ApplicationFiled: October 20, 2008Publication date: February 12, 2009Applicant: Fluke CorporationInventors: Shounan Luo, Wang Yong