By Frequency Sensitive Or Responsive Detection Patents (Class 324/520)
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Patent number: 6545485Abstract: An ultrasonic RFI source locator implements signal analysis to discriminate ultrasonic shocks emanating from power line equipment sources from ambient and other interference sources, as well as distinguish between specific type interference sources, such as corona and sparking discharge. The locator has a directional or contact ultrasonic sensor for receiving a signal representing the ultrasonic shocks from a targeted source, and includes signal processing circuitry to detect and compare the strengths of portions of the sensed signal that are modulated at whole integer multiples (harmonics) of an electrical power frequency (e.g., at 60 Hz and 120 Hz on a 60 Hz A/C power system, or 50 Hz and 100 Hz on a 50 Hz A/C power system) with each other, with the total signal and with selected non harmonic frequencies. The locator provides an operator indication of the result of this spectral analysis.Type: GrantFiled: January 21, 2000Date of Patent: April 8, 2003Assignee: Radar EngineersInventor: John D. Sanderson
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Patent number: 6516049Abstract: The current invention provides a method and apparatus for determining insertion loss in wireline communication systems. The method may be implemented with any modulation protocol but is particularly suited for multi-carrier modulation protocols such as discrete multi-tone (DMT). The method for calculation of the insertion loss uses a received signal and a discrete subset of frequency ranges, e.g. DMT tones, within that signal. For each of the subset of frequency ranges the average received power on each of the selected set of tones is determined. Next the average power on each received subset of tones is converted to log2 using a simple log2 estimation circuit that avoids the complexity associated with log tables and other prior art methods of computing logarithms. Then the sum of the log2 of the average power received in each of the selected subset of tone bins is determined.Type: GrantFiled: June 6, 2001Date of Patent: February 4, 2003Assignee: Ikanos Communications, Inc.Inventors: Sam Heidari, Behrooz Rezvani, Hojat Khelghati, Yuwen Su, Qasem Aldrubi
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Publication number: 20020163340Abstract: The present invention provides methods for using time domain analysis of NEXT, Return Loss and the like, in conjunction with the application of time or distance referenced limits to verify and determine compliance of the performance requirements of connections in a typical link. Time domain analysis of NEXT, Return Loss data and the like, suitably provides the performance characteristics of a link as a function of time or distance. When coupled with time or distance performance curves for connections, it can be determined if the transmission fault is at a connection or in the cable. The time limit curves for connections can be generated based on the frequency domain performance requirements for connecting hardware of a specific level of performance. The connection time limit curves thus provide an interpretation means to determine if the connection is within performance standards, allowing improved isolation of the fault condition.Type: ApplicationFiled: June 18, 2002Publication date: November 7, 2002Inventors: James R. Sciacero, James G. Tonti
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Patent number: 6477021Abstract: A system for determining whether arcing is present in an electrical circuit includes a sensor for monitoring a current waveform in the electrical circuit, and an arc fault detection circuit which determines whether an arc fault is present in response to the sensor. The arc fault detection circuit includes a controller which produces a trip signal in response to a determination that an arcing fault is present in the electrical circuit, and an inhibit/blocking function for preventing the production of the trip signal under one or more predetermined conditions.Type: GrantFiled: December 21, 1999Date of Patent: November 5, 2002Assignee: Square D CompanyInventors: Andy A. Haun, Brian G. Grattan, Kon B. Wong, Robert F. Dvorak, Gary W. Scott
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Patent number: 6466650Abstract: Telephone line service type identification is provided to a telephone technician in the field by the placement of one or more tuned circuit(s) across the telephone line. In one embodiment, an inexpensive tuned circuit such as a ceramic resonator forms a telecom service resonator ID device which is placed across a telephone line, either at the central office or at the customer premises. Injection of a test current at a predetermined frequency, and a suitable amplitude of the same indicates to the technician aspects of telecom service to that particular telephone line (e.g., the existence of POTS, ISDN, and/or xDSL) and or use of the telephone line by a home network such as HPNA. In another embodiment, a telecom service transponder ID device is formed to provide line service identification to an interrogating line technician. The telecom service transponder ID device is activated when the test signal including an appropriate frequency is present to cause excitation in the telecom service transponder ID device.Type: GrantFiled: June 13, 2000Date of Patent: October 15, 2002Assignee: Agere Systems Guardian Corp.Inventors: Jonathan H. Fischer, Donald R. Laturell, Lane A. Smith
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Patent number: 6459273Abstract: A sputtering arc fault detector (10) for a system having an electrical conductor (14) carrying current to a load. The sputtering arc fault detector includes a current monitor (64) coupled to the conductor for generating a variable signal responsive to behavior of the current in the conductor. A level detector (58) is coupled to the monitor and generates a first pulse when the variable signal exceeds a first level. A step detector (62) is coupled to the monitor and is responsive to rapid step increases of the variable signal. The step detector generates a second pulse when the variable signal exceeds a second level. An arc verifier (48), which is coupled to the level detector and the step detector, combines the first and second pulses, and generates a fault signal when the combined pulses exceed a third level.Type: GrantFiled: November 23, 1998Date of Patent: October 1, 2002Assignee: Siemens Energy & Automation, Inc.Inventors: Charles Randall Dollar, II, Elton C. Johnson
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Patent number: 6456097Abstract: A method for measuring the impedance of electrical distribution equipment includes: applying a voltage at a first selected frequency to electrical distribution equipment, waiting a delay time for transient effects to settle, measuring current through the electrical distribution equipment, and selecting additional frequencies to repeat the steps of applying, waiting, and measuring.Type: GrantFiled: December 29, 1999Date of Patent: September 24, 2002Assignee: General Electric CompanyInventor: Peter E. Sutherland
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Patent number: 6433978Abstract: An arc fault circuit interrupter (AFCI) device functions to provide protection from potentially dangerous arc faults. The arc fault detector can be used stand alone or in combination with circuit interrupting devices such as IDCIs and ALCIs. The AFCI device detects both AC line frequencies and high frequencies associated with arcing. Both average and instantaneous values of both AC line frequency and high frequency arcing signals are processed to generate an arc fault signal. The trip mechanism of the device trips on the occurrence of either an arc fault or a ground fault. The device allows the arc detector to differentiate between destructive high level arcing and low level arcing such as generated by typical household appliances and equipment. This serves to decrease the occurrence of false tripping.Type: GrantFiled: July 10, 2000Date of Patent: August 13, 2002Assignee: Leviton Manufacturing Co., Inc.Inventors: Benjamin B. Neiger, Roger M. Bradley, James N. Pearse, William J. Rose, Steve Campolo
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Patent number: 6430728Abstract: According to an example embodiment, the present invention is directed to a system and method for analyzing an integrated circuit. A laser is directed to the back side of an integrated circuit and causes local heating, which generates acoustic energy in the circuit. The acoustic energy propagation in the integrated circuit is detected via at least two detectors. Using the detected acoustic energy from the detectors, at least one circuit defect is detected and located.Type: GrantFiled: September 30, 1999Date of Patent: August 6, 2002Assignee: Advanced Micro Devices, Inc.Inventors: Rama R. Goruganthu, Jeffrey D. Birdsley, Michael R. Bruce, Brennan V. Davis, Rosalinda M. Ring
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Patent number: 6424162Abstract: An insulated device diagnosing system is capable of judging the deterioration, lifetime, and defects of a device. The intensity at each voltage phase angle is measured at a plurality of specific frequencies, taking high voltage phase angles as the abscissas. The deterioration, lifetime, and the kind and extent of abnormality of the device are judged from the pattern and intensity of the spectral distribution, which is obtained by peak-holding the measured intensity for a defined time period. According to the present invention, partial discharge can be measured highly sensitively and precisely to diagnose the deterioration, lifetime and the extent of defect of the device. As a result, the insulation reliability of the device can be improved, and the part of the device that should be repaired/replaced can be grasped before disassembly of the device, thereby cutting the maintenance cost.Type: GrantFiled: August 11, 1999Date of Patent: July 23, 2002Assignee: Hitachi, Ltd.Inventors: Toshiaki Rokunohe, Fumihiro Endo, Tokio Yamagiwa, Ryouichi Shinohara
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Patent number: 6421811Abstract: According to an example embodiment of the present invention, a defect detection approach involves detecting the existence of defects in an integrated circuit as a function of acoustic energy. Acoustic energy propagating through the device is detected. A parameter including information such as amplitude, frequency, phase, or a spectrum is developed from the detected energy and correlated to a particular defect in the device.Type: GrantFiled: September 30, 1999Date of Patent: July 16, 2002Assignee: Advanced Micro Devices, Inc.Inventors: Rama R. Goruganthu, Jeffrey D. Birdsley, Michael R. Bruce, Brennan V. Davis, Rosalinda M. Ring
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Patent number: 6417672Abstract: A method for detecting the presence of a bridge tap and other types of fault in a transmission line. Initially, test signals of predetermined frequencies are transmitted into a transmitting end of the transmission line. The test signals are received at a receiving end of the transmission line and the amplitudes of the received signal are measured. A frequency response of the transmission line is computed based on the measured amplitudes. The frequency response is then analyzed for the presence of a frequency-domain signature that corresponds to one of the detectable types of fault. The presence of a bridge tap or another type of fault is identified based on the detected frequency-domain signature. The frequency-domain signature associated with a bridge tap can comprise a set of one or more attenuation dips in the frequency response, with each attenuation dip corresponding to a local minima in the frequency response.Type: GrantFiled: August 11, 2000Date of Patent: July 9, 2002Assignee: Sunrise Telecom, Inc.Inventor: Raymond L. Chong
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Patent number: 6407893Abstract: An arc fault detector comprised as a stand alone unit and in combination with a ground fault circuit interrupter (GFCI) functions to provide protection from potentially dangerous arc fault conditions. When combined with a GFCI, the combination arc fault/ground fault circuit interrupter (AFCI/GFCI) provides protection from both arc fault and ground fault conditions. A single transformer is used to detect faults between neutral and ground and arc faults. An impedance splits the current flow into two portions so as to generate differential current proportional to the current flowing through the conductors. An early arcing detector periodically tests the AC line for high impedance between the device and a main breaker panel. The AFCI/GFCI device detects both AC line frequencies and high frequencies associated with arcing. Both average and instantaneous values of both AC line frequency and high frequency arcing signals are processed to generate an arc fault signal.Type: GrantFiled: October 2, 2000Date of Patent: June 18, 2002Assignee: Leviton Manufacturing Co., Inc.Inventors: Benjamin B. Neiger, Roger M. Bradley, James N. Pearse, William J. Rose
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Patent number: 6389110Abstract: Telephone line service type identification is provided to a telephone technician in the field by the placement of one or more tuned circuit(s) across the telephone line. In one embodiment, an inexpensive tuned circuit such as a ceramic resonator forms a telecom service resonator ID device which is placed across a telephone line, either at the central office or at the customer premises. Injection of a test current at a predetermined frequency, and a suitable amplitude of the same indicates to the technician aspects of telecom service to that particular telephone line (e.g., the existence of POTS, ISDN, and/or xDSL) and or use of the telephone line by a home network such as HPNA. In another embodiment, a telecom service transponder ID device is formed to provide line service identification to an interrogating line technician. The telecom service transponder ID device is activated when the test signal including an appropriate frequency is present to cause excitation in the telecom service transponder ID device.Type: GrantFiled: June 13, 2000Date of Patent: May 14, 2002Assignee: Agere Systems Guardian Corp.Inventors: Jonathan H. Fischer, Donald R. Laturell, Lane A. Smith
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Patent number: 6381269Abstract: A test system for a evaluating a digital signal link includes a data signal generator, a data signal receiver, a digital signal link to be tested and a test interference signal injection (TISI) network connected as part of the digital signal link. The TISI network includes a data signal input port for receiving digital data signals generated by the data signal generator, a data signal output port for providing the digital data signals to the data signal receiver, and a controlled impedance data signal path carrying the digital data signals between the data signal input port and the data signal output port. An interference signal input port receives interference signals over a range of frequencies from an interference signal generator. One or more directional couplers directionally couple the interference signals into the data signal path toward either the data signal output port or the data signal input port at an impedance that substantially matches the impedance of the digital signal link.Type: GrantFiled: May 28, 1999Date of Patent: April 30, 2002Assignee: Lucent Technologies Inc.Inventors: David A. Gradl, Michael L. Steinberger
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Patent number: 6348801Abstract: A method and a communications device are described, comprising a radio telephone (5) with connected antenna path (1) which can be used to locate precisely a defective area (F) in the antenna path (1) in order to be able to repair the antenna path (1) in a selective fashion. For this purpose, initially a wave with a starting frequency (f0) is coupled into the antenna path (1), and the amplitude of the standing wave at an angular position is measured. Then, the frequency of the wave is increased until a corresponding amplitude is detected at the same angular position. From the frequencies present then and from a reading (n) which indicates how often the corresponding amplitude has been obtained, the fault interval (Ed) between the detector (18) and defective area (F) is then calculated.Type: GrantFiled: March 23, 2000Date of Patent: February 19, 2002Assignee: Nokia Mobile Phones Ltd.Inventor: Andreas Pietsch
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Patent number: 6285193Abstract: The insulation resistance of a capacitor is accurately measured within a short period of time by applying AC signals at two different frequencies f1 and f2 to the capacitor to measure the impedance Z1 and Z2 of the capacitor at each frequency. The series resistance Rs and capacity c of the capacitor are obtained from the impedance Z1 at the higher frequency f1, and the insulation resistance Rp of the capacitor is obtained from the impedance Z2, series resistance Rs and capacity C at the lower frequency f2.Type: GrantFiled: September 28, 2000Date of Patent: September 4, 2001Assignee: Murata Manufacturing Co., Ltd.Inventor: Gaku Kamitani
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Patent number: 6275044Abstract: An electrical isolation device is provided for use in an electrical distribution network having a plurality of branch circuits each defined by line and neutral conductors connected between a power source and a load, the line conductor being electrically connected to one of a plurality of line buses at an electrical distribution panelboard, the neutral conductor being electrically connected to a neutral bus at the electrical distribution panelboard. The isolation device includes a capacitance coupled between the line and neutral conductor of each of the branch circuits and is designed to provide a low impedance path for an arcing fault occurring on the line conductor of the branch circuit. The capacitance is sufficiently large to provide power factor correcting current.Type: GrantFiled: July 15, 1998Date of Patent: August 14, 2001Assignee: Square D CompanyInventor: Gary W. Scott
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Patent number: 6249139Abstract: A method is described for taking a lifetime measurement of an ultra-thin dielectric layer. In order to discover the life time of the ultra-thin dielectric layer, the measurement comprises using about one half of a stress voltage to measure a time-dependent leakage current of the ultra-thin dielectric layer.Type: GrantFiled: September 9, 1999Date of Patent: June 19, 2001Assignees: United Microelectronics Corp., United Semiconductor Corp.Inventors: Kuan-Yu Fu, Mainn-Gwo Chen, Chuan H. Liu
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Patent number: 6242900Abstract: A partial discharge measurement system is provided which comprises a digital peak detection circuit. The partial discharge measurement system digitizes and detects both positive and negative slopes of a signal from an electrical device being tested. The partial discharge measurement system controls the shape of pulse capture windows in accordance with different modes of operation, and controls the timing of pulse data capture depending on the mode of operation and the polarity of the signal.Type: GrantFiled: June 10, 1998Date of Patent: June 5, 2001Assignee: Hubble IncorporatedInventors: Timothy J. Fawcett, Neil S. Fore
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Patent number: 6242922Abstract: A low cost mixed analog digital application specific integrated circuit (ASIC) includes a standard central processing it (CPU) programmed to execute a correlation function for arc detection. Use of a standard CPU is possible because need for digital fourier analysis is eliminated by the ASIC architecture. The SIC includes a power supply configured to be coupled to an AC power line for supplying power to the ASIC components, and further includes a current sensor coupled to a current-carrying conductor for generating a signal representative of current in the conductor. A first analog-to-digital converter (ADC), coupled in series with the current sensor, has its output coupled to a central processing unit (CPU). The CPU supplies a digital-to-analog converter (DAC) with a digital signal representative of a portion of the sensed current. The DAC supplies this signal, in analog form, to a summer, which also receives an output signal from the current sensor.Type: GrantFiled: November 6, 1998Date of Patent: June 5, 2001Assignee: General Electric CompanyInventors: Wolfgang Daum, Daniel Arthur Staver
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Patent number: 6239586Abstract: A breakdown voltage measurement system is provided which employs a digital peak detection circuit for peak voltage measurement. The breakdown voltage measurement system employs a voltage memory device for storing successive peak values obtained from the digital peak detection circuit. The breakdown voltage measurement system is programmable to commence searching of stored peak values following breakdown of a sample electrical device being tested to determine a voltage measurement immediately before the breakdown occurred.Type: GrantFiled: June 10, 1998Date of Patent: May 29, 2001Assignee: Hubbell IncorporatedInventors: Timothy J. Fawcett, Neil S. Fore
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Patent number: 6184688Abstract: The insulation resistance of a capacitor is accurately measured within a short period of time by applying AC signals at two different frequencies f1 and f2 to the capacitor to measure the impedance Z1 and Z2 of the capacitor at each frequency. The series resistance Rs and capacity C of the capacitor are obtained from the impedance Z1 at the higher frequency f1, and the insulation resistance Rp of the capacitor is obtained from the impedance Z2, series resistance Rs and capacity C at the lower frequency f2.Type: GrantFiled: May 4, 1998Date of Patent: February 6, 2001Assignee: Murata Manufacturing Co., Ltd.Inventor: Gaku Kamitani
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Patent number: 6177801Abstract: A method for detecting the presence of a bridge tap and other types of fault in a transmission line. Initially, test signals of predetermined frequencies are transmitted into a transmitting end of the transmission line. The test signals are received at a receiving end of the transmission line and the amplitudes of the received signal are measured. A frequency response of the transmission line is computed based on the measured amplitudes. The frequency response is then analyzed for the presence of a frequency-domain signature that corresponds to one of the detectable types of fault. The presence of a bridge tap or another type of fault is identified based on the detected frequency-domain signature. The frequency-domain signature associated with a bridge tap can comprise a set of one or more attenuation dips in the frequency response, with each attenuation dip corresponding to a local minima in the frequency response.Type: GrantFiled: April 21, 1999Date of Patent: January 23, 2001Assignee: Sunrise Telecom, Inc.Inventor: Raymond L. Chong
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Patent number: 6154032Abstract: A system for locating the particular circuit breaker associated with a branch circuit. The system includes a transmitter is connected to the hot lead of the branch circuit to inject a signal having a predetermined frequency. The system further includes identification circuits permanently associated with each circuit breaker. The identification circuit includes an indicator powered by a rectifier connected to the hot lead of the associated branch circuit. A band pass filter within the identification circuit passes the predetermined frequency, which when present biases the gate of a controlled switch which is placed in series with the indicator lamp such that when the predetermined frequency is present on the hot lead the indicator lamp is turned on.Type: GrantFiled: May 29, 1998Date of Patent: November 28, 2000Assignee: Unique Technologies, LLCInventors: Ronald A. Coia, Joachim Wottrich
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Patent number: 6144290Abstract: The invention concerns a control device for the emission of carrier currents on a low voltage network, comprising a sensing module (1), by magnetic coupling, for generating from carrier currents detected high frequency signals (shdf), a local oscillator (2) generating a reference frequency radioelectic signal (fr) of a frequency comprised in the signal band (shdf) and a frequency-changing module (3) delivering an audio baseband signal (sbb) based on the (shdf) and (fr) signals. A demodulating circuit (4) delivers a detected low frequency signal (sdbf) based on the baseband signal (sbb) to a transducer circuit (50, 51) generating a sound signal controlling the current carrier frames. The invention is applicable to the implementation and management of current carrier installations on low voltage networks.Type: GrantFiled: July 20, 1999Date of Patent: November 7, 2000Assignee: Electricite de France, Service NationalInventors: Guillaume Duval, Daniel Chaffanjon
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Patent number: 6144721Abstract: A line pair testing and fault diagnostic apparatus implementing three-terminal measurement techniques using a multiple frequency source waveform transmission to propagate a reflected waveform. The apparatus implements a microcomputer circuit executing a program. The program has frequency domain analysis algorithms to process the reflected waveform to provide a craftsperson with the electrical characteristic data of a line pair to inform the craftsperson the existence of a line pair fault and the location of the fault in the line pair. The apparatus implements relays for switching between several diagnostics circuits within the apparatus for providing the craftsperson with numerous methods and techniques for troubleshooting a line pair.Type: GrantFiled: January 3, 1997Date of Patent: November 7, 2000Assignee: Communications Technology CorporationInventor: Charles D. Stephens
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Patent number: 6130540Abstract: In a measurement system for electric disturbances in a metalen-capsulated high-voltage switchgear having at least one measurement probe for each phase for decoupling of electromagnetic interference signals, both the interference signals and the useful voltage are scanned by the same measurement probe in each phase, and both are made accessible, separately from one another, at a filter arrangement.Type: GrantFiled: April 21, 1998Date of Patent: October 10, 2000Assignee: Siemens AGInventor: Norbert Achatz
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Patent number: 6128169Abstract: An arc fault detector comprised as a stand alone unit and in combination with a ground fault circuit interrupter (GFCI) functions to provide protection from potentially dangerous arc fault conditions. When combined with a GFCI, the combination arc fault/ground fault circuit interrupter (AFCI/GFCI) provides protection from both arc fault and ground fault conditions. A single transformer is used to detect faults between neutral and ground and arc faults. An impedance splits the current flow into two portions so as to generate differential current proportional to the current flowing through the conductors. An early arcing detector periodically tests the AC line for high impedance between the device and a main breaker panel. The AFCI/GFCI device detects both AC line frequencies and high frequencies associated with arcing. Both average and instantaneous values of both AC line frequency and high frequency arcing signals are processed to generate an arc fault signal.Type: GrantFiled: December 19, 1997Date of Patent: October 3, 2000Assignee: Leviton Manufacturing Co., Inc.Inventors: Benjamin B. Neiger, Roger M. Bradley, James N. Pearse, William J. Rose
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Patent number: 6072317Abstract: A portable tester plugs into a receptacle in a branch circuit of an electric power distribution system to verify protection against arc faults, line to ground faults and neutral to ground faults provided by a circuit breaker located at a remote load center or by ground fault and, or arc fault interrupters in the receptacle, and also checks for proper wiring. The arc fault detector gates phased back rectified half cycles of the ac power to generate step changes in the instantaneous amplitude of current in the branch circuit which mimic the repetitive striking of an arc. Preferably, only half cycles at least 60 ms apart are gated so that the user can verify the time to trip with a watch and can count the gated half cycles to trip by counting pulses generated by a light emitting diode (LED) in the gating circuit.Type: GrantFiled: March 27, 1998Date of Patent: June 6, 2000Assignee: Eaton CorporationInventor: Raymond Warren Mackenzie
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Patent number: 6046594Abstract: A method and apparatus for measuring electrical characteristics (e.g. current, voltage, phase, etc.) between a power source and a load at a set of harmonic frequencies to determine information about the load (e.g., load impedance, power dissipation, etc). According to one aspect of the invention, a first circuit detects a set of electrical characteristics (e.g., current, voltage, and/or phase) of a signal between the power source and the load. A second circuit, coupled to the first circuit to receive the set of electrical characteristics, provides data representing the set of electrical characteristics at a harmonic frequency associated with the signal. A third circuit, coupled to the second circuit, receives the data and determines information about the load (e.g., impedance, power dissipation, discharge current, etc.) at the harmonic frequency.Type: GrantFiled: February 11, 1997Date of Patent: April 4, 2000Assignee: Advanced Energy Voorhees, Inc.Inventor: Anton Mavretic
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Patent number: 6043662Abstract: The breakdown of an ultra-thin dielectric layer is detected by applying a test signal to the layer. Measurements are taken of noise signals present in the layer during the application of the test signal. At breakdown, a significant increase occurs in the amplitude of the measured noise signals. Similarly, fluctuations in quiescent current, I.sub.DDQ, (I.sub.DDQ noise signals), rather than the values of I.sub.DDQ, are utilized during testing as the basis for detecting defects in integrated circuits.Type: GrantFiled: January 2, 1998Date of Patent: March 28, 2000Inventors: Glenn Baldwin Alers, Kathleen Susan Krisch, Bonnie Elaine Weir
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Patent number: 5994890Abstract: A harmonics survey system includes an induction coil arranged so as to cross over a magnetic flux generated by a current passing a distribution line to be surveyed and adapted to detect a detection current caused by an electro motive force in proportion to the current passing the distribution line, a harmonics detection unit operatively connected to the induction coil and adapted to detect a fundamental component and a harmonic component of the detection current detected by the induction coil, a harmonic current content operation unit for operating the harmonic current content of the harmonic component with respect to the fundamental component detected by the harmonic detection unit, and an indication unit for indicating the harmonic current content operated by the harmonic current operation unit.Type: GrantFiled: November 4, 1997Date of Patent: November 30, 1999Assignee: Togami Electric Mfg. Co., Ltd.Inventors: Yoshihiro Kajiwara, Takeru Aishima
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Patent number: 5982181Abstract: An insulated device diagnosing system is capable of judging the deterioration, lifetime, and defects of a device. The intensity at each voltage phase angle is measured at a plurality of specific frequencies, taking high voltage phase angles as the abscissas. The deterioration, lifetime, and the kind and extent of abnormality of the device are judged from the pattern and intensity of the spectral distribution, which is obtained by peak-holding the measured intensity for a defined time period. According to the present invention, partial discharge can be measured highly sensitively and precisely to diagnose the deterioration, lifetime and the extent of defect of the device. As a result, the insulation reliability of the device can be improved, and the part of the device that should be repaired/replaced can be grasped before disassembly of the device, thereby cutting the maintenance cost.Type: GrantFiled: December 8, 1997Date of Patent: November 9, 1999Assignee: Hitachi, Ltd.Inventors: Toshiaki Rokunohe, Fumihiro Endo, Tokio Yamagiwa, Ryouichi Shinohara
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Patent number: 5977773Abstract: A non-intrusive electrical cable tester determines the nature and location of a discontinuity in a cable through application of an oscillating signal to one end of the cable. The frequency of the oscillating signal is varied in increments until a minimum, close to zero voltage is measured at a signal injection point which is indicative of a minimum impedance at that point. The frequency of the test signal at which the minimum impedance occurs is then employed to determine the distance to the discontinuity by employing a formula which relates this distance to the signal frequency and the velocity factor of the cable. A numerically controlled oscillator is provided to generate the oscillating signal, and a microcontroller automatically controls operation of the cable tester to make the desired measurements and display the results. The device is contained in a portable housing which may be hand held to facilitate convenient use of the device in difficult to access locations.Type: GrantFiled: August 15, 1997Date of Patent: November 2, 1999Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space AdministrationInventors: Pedro J. Medelius, Howard J. Simpson
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Patent number: 5969920Abstract: A test circuit for arc fault detectors of the type which respond to step changes in ac current over time generated each time an arc is struck includes a low frequency relaxation oscillator which generates a repetitive signal with step changes like those produced by an arc fault. The relaxation oscillator includes a capacitor charged through a resistor and shunted by a voltage breakdown device, preferably a diac. The capacitor is rapidly discharged when its voltage reaches the breakdown voltage of the voltage breakdown device to generate the step change which is input to the arc fault detector. With a repetition rate of the relaxation oscillator not greater than about 15 repetitions per second (rps), and preferably about 5 rps, a user can manually determine the time to trip to verify arc fault detector operation.Type: GrantFiled: March 27, 1998Date of Patent: October 19, 1999Assignee: Eaton CorporationInventor: Raymond Warren Mackenzie
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Patent number: 5903143Abstract: This invention is an inexpensive probe apparatus operating at high precision that can be used for both low-frequency and high-frequency measurements. A line with a first and second conductor is extended from a probe connected to a circuit component. A low-frequency or high-frequency device is alternately connected to the line. A third common conductor runs parallel to the aforementioned line and a resistor and capacitor is connected between the probe end of the aforementioned second conductor and the aforementioned common conductor.Type: GrantFiled: June 3, 1997Date of Patent: May 11, 1999Assignee: Hewlett-Packard CompanyInventors: Kohei Mochizuki, Satoshi Habu
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Patent number: 5903159Abstract: A microwave sensor includes a case 1 of an object apparatus in which a discharge may occur; the object apparatus 2; an antenna 3 which is attached to the object apparatus case 1 and receives a microwave signal generated by a discharge; a signal processing unit 4 which is connected to the antenna 3, amplifies and detects the microwave signal, mixes the microwave signal with an oscillating signal, converts the mixed signal to a video signal, and amplifies the video signal; and an output terminal 13 through which the video signal is output.Type: GrantFiled: December 5, 1997Date of Patent: May 11, 1999Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Tomoyuki Miyata, Hiroshi Otani
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Patent number: 5903157Abstract: In a measuring system for an enclosed high-voltage switchgear having at least two poles, each of which is phase segregated, and with sensors for dielectric noise and a detector device connected to them for outputting a signal in the event of an noise, a time comparator is provided that blocks the output of a signal if the time difference between two noise signals from sensors of different phases is less than a certain interval of time, in particular an adjustable interval.Type: GrantFiled: December 8, 1997Date of Patent: May 11, 1999Assignee: Siemens AktiengesellschaftInventors: Norbert Achatz, Jorg Gorablenkow
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Patent number: 5859590Abstract: A fault sensor device comprising a receiver (3; 3A; 3B) for receiving microwaves (2, 8) radiated from an object to be monitored (1; 1A; 1B; 1C; 1D; 1E; 1F), a detector (4) connected to the receiver (3; 3A; 3B) for converting and outputting the microwaves (2, 8) into a video signal (2S4; 2S21), and a signal processor (5) for converting the video signal (2S4, 2S21) output by the detector (4) into a presentation signal (2S5) and outputting the presentation signal (2S5) to an external presentation device (91; 91A), and for determining whether or not the microwaves (2, 8) received are associated with a fault, based on one of the duration and the frequency of the video signal (2S4; 2S21) and the level of the video signal, and for issuing an alarm signal (2S6) when the determination reveals that the microwaves are associated with the fault.Type: GrantFiled: September 19, 1997Date of Patent: January 12, 1999Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroshi Otani
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Patent number: 5818237Abstract: Arcing faults in an ac current are detected by apparatus which is responsive to a predetermined randomness in step increases in the current to eliminate false tripping caused by regularly occurring discontinuities produced by loads such as dimmers. A signal conditioner generates a bandwidth limited di/dt signal having pulses produced by the step increases in current. In one embodiment, a first tracking circuit tracks the envelope of the di/dt signal with a first time constant. A second tracking circuit also tracks the di/dt envelope, but with a second, shorter time constant. An arcing fault is indicated if the second tracking signal falls to a predetermined fraction of the fist tracking signal. This circuit may be used alone to detect arcing faults or to increase the sensitivity to arcing faults over dimmers of a circuit which responds to a time attenuated integrated valve of the pulses in the di/dt signal.Type: GrantFiled: June 10, 1996Date of Patent: October 6, 1998Assignee: Eaton CorporationInventors: Joseph C. Zuercher, Raymond W. MacKenzie, Steven C. Schmalz
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Patent number: 5804975Abstract: The breakdown of an ultra-thin dielectric layer is detected by applying a test signal to the layer. Measurements are taken of noise signals present in the layer during the application of the test signal. At breakdown, a significant increase occurs in the amplitude of the measured noise signals.Type: GrantFiled: September 18, 1996Date of Patent: September 8, 1998Assignee: Lucent Technologies Inc.Inventors: Glenn Baldwin Alers, Kathleen Susan Krisch, Bonnie Elaine Weir
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Methods and apparatus for removing error due to decaying offsets from measured power system currents
Patent number: 5798932Abstract: A digital decaying current offset correction method and apparatus, in one aspect, separates the requirements of detecting fault existence from the requirements of detecting fault location. Once the decaying offset removal routine is initiated, current and voltage are sampled and, for each current and voltage sample, current and voltage phasors are generated. The current phasor values, which are not offset corrected, may be used to determine whether to trip a breaker. Once the breaker is tripped, the decaying offsets are removed from the current phasors. The offset corrected current phasors are then used to locate the fault.Type: GrantFiled: May 21, 1996Date of Patent: August 25, 1998Assignee: General Electric CompanyInventors: William James Premerlani, Mark Gerard Adamiak, Dingari Sreenivas, Eyyunni Venugopal -
Patent number: 5796257Abstract: A system for detecting a fault in a power line (1) includes, in the power line (1), a first circuit (4) capable of attenuating signals within a first frequency band, which is centered on a first frequency, substantially more than it attenuates signals outside the first frequency band, and, a second circuit (5) connected to the power line (1) on one side of the first circuit (4), the second circuit (5) being capable of extracting signals within a second frequency band that includes the first frequency. The relative levels of two signals extracted by the second circuit (5), are detected and signalled, the two signals being at respective frequencies which the first circuit is capable of attenuating by different relative amounts.Type: GrantFiled: June 10, 1997Date of Patent: August 18, 1998Assignee: The University of BathInventor: Allan Thomas Johns
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Patent number: 5729421Abstract: A circuit analyzing system includes a current transformer for extracting current from a phase or neutral conductor of a three phase line, a filter connected to the output of the current transformer and functioning to substantially trap current at the fundamental frequency while substantially passing currents at various harmonic frequencies thereof, and signal processing circuitry connected to the output of the filter to perform various functions with the harmonic frequency current input thereto. Among these functions, as shown in various preferred embodiments, are measurement of the harmonic signal in RMS and conveyance of the output to a display instrument for a user or utility's convenience in monitoring harmonic frequency circuits, which have become more corrosion with the advent of electronic equipment having internal power supplies such as personal computers, work stations, printers, and the like.Type: GrantFiled: February 21, 1996Date of Patent: March 17, 1998Assignee: Leviton Manufacturing Co., Inc.Inventors: Bernard Gershen, Alfred J. Lombardi, James E. Meehan, Saul Rosenbaum
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Patent number: 5726576Abstract: A microwave sensor includes a case 1 of an object apparatus in which a discharge may occur; the object apparatus 2; an antenna 3 which is attached to the object apparatus case 1 and receives a microwave signal generated by a discharge; a signal processing unit 4 which is connected to the antenna 3, amplifies and detects the microwave signal, and amplifies the detected video signal; and an output terminal 13 through which the video signal is output.Type: GrantFiled: April 10, 1996Date of Patent: March 10, 1998Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Tomoyuki Miyata, Hiroshi Otani
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Patent number: 5726577Abstract: Series arcs in an ac circuit are discriminated from other phenomenon by analyzing the timing between pulses in a second derivative of the current signal. A first timer starts timing upon detection of a first pulse in the second derivative of current signal. Time out of the first timer starts a second timer which times a second interval or window during which a series arcing fault will generate a second pulse of opposite polarity to the first pulse. Detection of the first pulse followed by a second pulse of opposite polarity during the window sets a flip-flop to record the event. When a predetermined number of events are counted by a counter within a given time-period set by a third timer, an output signal indicating an arcing fault is generated. If the second pulse is generated before the window opens, or a third pulse occurs during the window, the flip-flop cannot be set so that other events such as the switching of a dimmer do not generate a false output signal.Type: GrantFiled: April 17, 1996Date of Patent: March 10, 1998Assignee: Eaton CorporationInventors: Joseph C. Engel, Raymond W. Mackenzie
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Patent number: 5714885Abstract: Apparatus for detecting faults in buried conductors, a transmitter adapted to transmit electro-magnetic signals down the buried conductor; this signal is provided to increase an electro-magnetic path or corridor existing at the surface above the buried conductor. The invention also relates to a detecting means adapted to detect the electro-magnetic path or corridor, and to detect electro-magnetic patches formed in the path or corridor. These patches are located over the faults, and they are characterized by presence of an increased level of electro-magnetic energy caused by the faults. The transmitter means are adapted to transmit a composite signal comprising a carrier signal transmitted by a carrier signal means and a low frequency signal transmitted by a low frequency means. The carrier signal means comprise an RF carrier signal means and an audio tone signal means; the audio tone signal means are adapted to modulate signals transmitted by the RF carrier signal means.Type: GrantFiled: September 25, 1995Date of Patent: February 3, 1998Inventor: Don A. Lulham
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Patent number: 5682101Abstract: A system to detect arcing faults in an electrical distribution system with a line conductor connected to a utility power transformer. The system monitors the rate of change of electrical current in the line conductor and produces a signal which represents the rate of change. The system produces a pulse each time the rate-of-change signal exceeds a selected threshold, filters the rate-of-change signal and/or the pulses to substantially eliminate a signal or pulse which represents changes in the electrical current outside a selected frequency range, monitors the remaining pulses to detect when the number of pulses that occur within a selected time interval exceeds a predetermined threshold, and generates an arc-fault-detection signal in response to the occurrence of a number of pulses which exceed the threshold within the selected time interval.Type: GrantFiled: February 13, 1996Date of Patent: October 28, 1997Assignee: Square D CompanyInventors: Stanley J. Brooks, James W. Dickens, Walter H. Strader
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Patent number: 5680039Abstract: This invention is an inexpensive probe apparatus operating at high precision that can be used for both low-frequency and high-frequency measurements. A line with a first and second conductor is extended from a probe connected to a circuit component. A low-frequency or high-frequency device is alternately connected to the line. A third common conductor runs parallel to the aforementioned line and a resistor and capacitor is connected between the probe end of the aforementioned second conductor and the aforementioned common conductor.Type: GrantFiled: February 2, 1995Date of Patent: October 21, 1997Assignee: Hewlett-Packard CompanyInventors: Kohei Mochizuki, Satoshi Habu