Abstract: A broad-band EMP surge diverter in a coaxial line with a waveguide (20) placed in an outer conductor (10) and electrically connected via a short-circuit link (24) to the inner conductor (30) of the coaxial line, whereby sections of conductor (31, 32, 33, 34, 35) of corresponding wave impedance in the coaxial line give rise to a frequency band of substantial band width.

Abstract: In a multiple phase system for supplying power from an AC source to nonlinear loads, a device for substantially eliminating currents in a neutral wire. The device includes a completely-passive parallel resonant circuit having three passive electrical branches connected in parallel tuned to a third harmonic frequency of the AC source. The three branches comprise a first branch consisting of a capacitor, a second branch consisting of a reactor, and a third branch consisting of a resistor. The resonant circuit is connected to the neutral wire.

Abstract: A conventional ground fault circuit interrupter (GFCI) is modified to provide frequency-selective current protection. A control element is connected in series with the line path (or return path) of the GFCI, and a bypass element is connected in parallel with the combination of the control element and the line path (or return path) of the GFCI. Under normal conditions, little or no current flows through the bypass element. However, frequency response characteristics of the control and/or bypass elements are such that a frequency-selective component of the current (i.e. high-pass, low-pass or band-pass) is diverted through the bypass element. When the magnitude of the frequency-selective component reaches a predetermined value, the bypass current flow causes sensing of a resulting current imbalance and tripping of the GFCI.

Abstract: An ESD protection network is described which prevents high voltage oxide stress. The network consists of a filter network (such as a blocking capacitor) and diode protection elements. The filter network can be designed for several types of ESD protection functions. It can be designed to provide voltage reduction for ESD pulses, and to selectively block the frequency components of ESD pulses.

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode. Various hybrid combinations are also contemplated where in-line and/or bypass fuses are combined with other circuit components. One example is, a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: A surge protection circuit is coupled to the wires that transport digital signals between a local unit, such as an ONU, and a remote unit, such as a NID. The surge protection circuit includes a coordinating impedance having a capacitive element connected in series with the twisted pair wires coupling the ONU to the NID. The coordinating impedance couples a primary shunt protector and a secondary shunt protector. Various embodiments of the surge protection circuit comprise coordinating impedance devices including a series connected: capacitor and resistor, capacitor and inductor, and capacitor, inductor, and resistor. By using a capacitive element in the coordinating impedance, the signal loss through the surge protector is significantly reduced for 10 Base-T and 100 Base-T Ethernet systems. Further, the added inductance may become part of an integrated low-pass filter that further reduces signal loss at high frequencies.

Abstract: An apparatus and method for attenuating high frequency transients on AC power lines from damaging sensitive electrical and electronic circuits in an electrical load coupled to the AC power lines is provided. The AC power line has an earth ground and the electrical load has an electrical load ground. A continuous attenuator circuit is used for attenuating high frequency transients electrically coupled between the earth ground and the electrical load ground. The continuous attenuator circuit includes a plurality of toroid cores and a single continuous strand of wire being wound individually and sequentially a number of turns around each of the plurality of toroid cores.

Abstract: A power unit for a grid pulsed O-type microwave tube (1) having a cathode (2) and a collector (3), comprises a cathode unit (5) and a collector unit (6), each having two output terminals (7, 8; 9, 10). A first and a second capacitor (C1, C2) are connected between the output terminals of the respective unit (5, 6). One output terminal (7) of the cathode unit (5) is connected to the cathode (2) of the tube (1), while the other (8) is connected to a ground terminal. One output terminal (9) of the collector unit (6) is connected to the collector (3) of the tube (1), while the other (10) is interconnected with that one (7) of the output terminals of the cathode unit (5) that is connected to the cathode (2) of the tube (1). To minimize crosstalk caused by the collector unit (6) across the first capacitor (C1), the output terminals (9, 10) of the collector unit (6) are connected to said second capacitor (C2) via non-capacitive impedances (Z1, Z2), and to said ground terminal via decoupling capacitors (C31, C32).

Abstract: The present invention relates to a passive electronic component architecture employed in conjunction with various dielectric and combinations of dielectric materials to provide one or more differential and common mode filters for the suppression of electromagnetic emissions and surge protection. The architecture allows single or multiple components to be assembled within a single package such as an integrated circuit or connector. The component's architecture is dielectric independent and provides for integration of various electrical characteristics within a single component to perform the functions of filtering, decoupling, fusing and surge suppression, alone or in combination.

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode. Various hybrid combinations are also contemplated where in-line and/or bypass fuses are combined with other circuit components. One example is, a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: According to an aspect of the present invention there is provided an LSI device having an output terminal outputting a data, comprising a data output circuit connected to the output terminal and capable of adjusting an output impedance thereof; and an adjustment circuit which detects a transient voltage at the output terminal when an output logic of the data output circuit is switched in a condition that a transmission line not terminated by a terminating resistor is connected to the output terminal, compares the transient voltage with a reference voltage, and adjusts the output impedance of the data output circuit so as to match a characteristic impedance of the transmission line.

Abstract: A power line filter connected to single-phase power lines (110-230 VAC, 50-60 Hz) enables transmission of HomePNA-type home network signals between network nodes connected to the main power lines as a network medium. The filter includes fuse resistors (R1, R2) that limit the current from the main power line, a transit diode circuit that clamps the bolts to a prescribed limit, eliminating energy that may be present in main power spikes. A pair of X2-type capacitors pass the 1 MHz or higher HomePNA signals, while rejecting the 50-60 Hz main power signal. A choke-type inductor eliminates any residual high voltage signals in the 50-60 Hz range by short circuiting the power signals, while maintaining a high impedance at the 1 MHz range, enabling the HomePNA signals to be safely passed to the RJ-11 connector of a physical layer transceiver of the Home Network Node.

Abstract: An overvoltage and transient protection circuit with extended bandwidth is provided for the protection of a low voltage test signal path (210) such as a test signal path in a multimeter. The disclosed circuit maintains the integrity of a test signal (TS) (114) transmitted by the test signal path (210) by minimizing the effect that unwanted capacitive coupling would otherwise have on the frequency transmission capability of the circuit. During normal operation of the circuit, a test signal path isolation circuit (218) is held between the test signal (TS) (114) and an equivalent buffered guard signal (GS) 227. Held between these equivalent values (TS=GS), no (or minimal) current will be generated in the components of the test signal path isolation circuit (218) as a result of parasitic capacitance. The guard signal (65) (227) is used with guard traces (412) and guard planes (414) to isolate other parts of the test signal path in much the same way.

Abstract: The present invention relates to a polymer fuse apparatus that provides bypass fuse protection. A polymer bypass fuse is comprised of an electrical conductor wherein a portion of the conductor is surrounded by an internal electrode, which is then surrounded by a layer of polymeric positive temperature coefficient (PTC) material, which is then surrounded by a conductive material similar to that of the internal electrode.Various hybrid combinations are also contemplated where in-line and/or bypass fuses are combined with other circuit components. One example is, a plurality of in-line and bypass fuses combined with a differential and common mode filter, which itself consists of a plurality of common ground conductive plates maintaining first and second electrode plates between the various conductive plates, all of which are surrounded by a material having predetermined electrical characteristics to provide fail safe filter and circuit protection.

Abstract: The present invention relates to a passive electronic component architecture employed in conjunction with various dielectric and combinations of dielectric materials to provide a differential and common mode filter for the suppression of electromagnetic emissions and surge protection. The architecture allows single or multiple components to be assembled within a single package such as an integrated circuit or connector. The component's architecture is dielectric independent and provides for integration of various electrical characteristics within a single component to perform the functions of filtering, fusing and surge suppression, alone or in combination.

Abstract: An apparatus and method for protecting hardware devices using a spiral inductor. The surge suppressor protects hardware devices from electric surges by isolating the radio frequency from an inner conductor. The surge suppressor includes a housing, an inner conductor, a surge blocking device, and a spiral inductor. The surge blocking device is inserted in series with the hardware devices for blocking the flow of electrical energy therethrough. The spiral inductor is coupled to the surge blocking device and is shunted to ground for discharging the electrical surge.

Abstract: The present invention provides protection from electromagnetic interference and electrostatic discharge. The invention teaches a shielding conductor surface enclosure, an interior shielding conductor plane, a contact conductor from the shielding conductor plane and the shielding conductor surface enclosure, a path for electromagnetic signals to pass through a shielding conductor plane, a filter network, and an electrostatic voltage clamp. Protection is provided by filtering the incoming signals, electrically coupling the signals of an undesired bandwidth to a shield barrier, and electrically coupling signals of an undesired voltage to a shield barrier. The shield surface is physically differentiated from the ground plane surface.

Abstract: A common mode signal attenuator includes a magnetic core, and a communications cable having at least one conductor adapted to transmit a communications signal. The communications cable is magnetically coupled to the core to form an inductive element having a magnetic flux path passing through the core. The inductive element has a volt-time capacity of at least about 0.0001 volt-seconds.An electrical transient suppression system includes an electronic device having a ground path, a communications cable, and a magnetic core. The communications cable has at least one conductor adapted to transmit a communications signal and is connected to the electronic device. The communications cable is magnetically coupled to the core to form a common mode signal attenuator having an inductance of about at least 10 times the inductance of the ground path.A method for reducing electrical transients in a communications cable includes magnetically coupling the communications cable to a magnetic core.

Abstract: Apparatus for blocking a d.c. component of a signal, comprises an electrically conductive signal path (1, 2) having a gap (3) in it preventing direct current flow across the gap, and an electrically conductive element (4) spaced from the path by a body (5) of dielectric material, the element (4) being located and dimensioned such that in use an a.c. signal is coupled from the signal path (1) into the element (4) at one side of the gap, and from tie element (4) into the signal path (2) at the other side of the gap. The apparatus optionally includes a quarter wavelength earthing strap between the signal path and ground potential. The apparatus includes means for providing an a.c. signal feed into a hazardous environment in an intrinsically safe manner.

Abstract: A single circuit protection module for protecting a first T/R pair that is electrically coupled to a punch down connection block from undesirable transients and longitudinal currents that appear on a second T/R pair that is electrically coupled to the punch down block and to the first T/R pair through the punch down block.

Abstract: The present invention relates to a passive electronic component architecture employed in conjunction with various dielectric and combinations of dielectric materials to provide one or more differential and common mode filters for the suppression of electromagnetic emissions and surge protection. The architecture allows single or multiple components to be assembled within a single package such as an integrated circuit or connector. The component's architecture is dielectric independent and provides for integration of various electrical characteristics within a single component to perform the functions of filtering, decoupling, fusing and surge suppression, alone or in combination.

Abstract: A telecommunications network (10) includes a main distribution frame (12) that receives telecommunications traffic carried over individual tip and ring signal line pairs (20) from trunks (18). The main distribution frame (12) provides the individual tip and ring signal line pairs (20) to a protector block (14). The protector block (14) includes a connector (22) for each individual tip and ring signal line pair (20). The connector (22) has a first terminal (24) that provides external access to low frequency voice band telecommunications traffic for POTS providers. The connector (22) has a second terminal (26) that provides external access to high frequency telecommunications traffic, such as ADSL for ADSL providers. The external access capability allows for the unbundling of physical connections at the main distribution frame (12) in order to provide competitive access to subscribers.

Abstract: A circuit for grounding a signal at a first frequency and at a second frequency. The circuit includes a first capacitor and an inductor in series and a second capacitor in parallel with the first capacitor and inductor. The first capacitor is series resonant at the first frequency and the second capacitor is series resonant at the second frequency. The inductance of the inductor is selected so the combination of the packaging inductance of the first capacitor and the inductor parallel resonants with the second capacitor at a frequency lower than the second frequency and higher than the first frequency, where the second frequency is greater than the first frequency. The grounding circuit may be used to provide a second input to a balanced RF mixer where the RF mixer receives a RF signal at the second frequency at a first input and generates an IF signal at the first frequency.

Abstract: In this invention, a whole-chip ESD protection scheme with the SCR string or the SCR/diode-mixed string are proposed to protect the mixed-voltage CMOS IC's against the ESD damage. The SCR string or the SCR/diode-mixed string is placed between the separated power lines. The ESD current is arranged to be discharged through the SCR string or the SCR/diode-mixed string and the ESD clamps between the power lines. Therefore, the internal circuits and the interface circuits between the circuits with different power supplies can be prevented from ESD damages. The number of the SCR's or the diodes in the SCR string or the SCR/diode-mixed string connected between the different power lines is dependent on the voltage difference between the different power supplies in the mixed-voltage CMOS IC's. When the IC is in the normal operating conditions, such SCR string or the SCR/diode-mixed string between the different power lines is kept off to maintain the independence of the power supplies in the mixed-voltage COMS IC.

Abstract: A voltage variable capacitor (VVC) is made by placing an intercalation compound between two electrodes of a capacitor. The VVC has a reservoir of an intercalant in proximity with the intercalation compound. The two materials are chosen from those known to exhibit the intercalation reaction. The extent of the intercalation reaction is controlled by applying a voltage to the intercalant reservoir and the intercalation compound. A variable capacitor is created by applying a signal to the device and appropriately controlling the .epsilon. of the device by using the input control voltages.

Abstract: A differential protection device includes a current transformer comprising a toroid formed by a magnetic core, primary windings formed by the active conductors of the installation and a secondary winding at the terminals of which a differential fault signal is established when a differential fault occurs in the primary windings, a tripping relay of a current breaking apparatus, and a secondary connection circuit connecting the relay to the terminals of the secondary winding, the secondary connection circuit being arranged to bring about tripping when the signal exceeds a preset threshold. The above-mentioned secondary circuit comprises a full-wave rectifier and a capacitor, connected in parallel with the secondary winding of the toroid, and the magnetic core is made of a nanocrystalline material.

Abstract: For use in a boost converter having a main boost switch, a boost inductor, a boost diode coupled to the boost inductor and the main boost switch and a resonant, passive snubber coupled to the boost inductor and the main boost switch that limits reverse recovery currents in the boost diode during a turn-on of the main boost switch, a peak voltage clamping circuit for, and method of, reducing voltage stress on the main boost switch caused by operation of the snubber. In one embodiment, the circuit includes a blocking switch and a zener diode, coupled in series between the main boost switch and the boost diode, that cooperate to provide a conductive path from the main boost switch to an output of the boost converter for electrical currents that exceed a predetermined peak voltage value thereby to reduce the voltage stress on the main boost switch.

Abstract: An overcurrent protection circuit for a switching mode power supply which has a switching transformer for transforming a rectified voltage into a plurality of drive voltages and a pulse width modulation circuit for generating a pulse width modulation signal in response to a desired one of the drive voltages from the switching transformer. The overcurrent protection circuit is connected between a drive voltage output terminal of the switching transformer and a drive voltage input terminal of the pulse width modulation circuit. The overcurrent protection circuit consists of a parallel circuit composed of an inductance and a resistance. When the switching transformer is short-circuited, the overcurrent protection circuit accelerates a drop of the drive voltage which is supplied from the switching transformer to the pulse width modulation circuit.

Abstract: A method and apparatus are provided for protecting a pair of telephone lines and similar data communication channels from overvoltage and transients. A filter for filtering noise and transient voltage signals above desired data signals on telephone lines and similar data communication channels includes a longitudinal transformer. The longitudinal transformer includes a single transformer core and a pair of coils. A first one of the coils is connected in series with a first telephone line or a first similar data communication channel. A second one of the coils is connected in series with a second telephone line or a second similar data communication channel. The pair of coils are substantially identical; each coil having an identical number of turns. A high impedance is provided with the longitudinal transformer to noise and transient voltage signals above desired data signals. A low impedance is provided with the longitudinal transformer to desired data signals.

Abstract: A high-frequency composite part includes a high-frequency switch and an amplifier in a transmission circuit side among high-frequency parts constituting a PHS portable telephone. In the telephone, the high-frequency switch is used for switching between the connection of the transmission circuit Tx and an antenna, and the connection of a receiving circuit Rx and the antenna. The amplifier at the Tx side amplifies a signal to be transmitted which has been converted into an RF signal and passes through a filter at the Tx side, and sends it to the high-frequency switch.

Abstract: A lightning suppression system comprising a directional coupler, a quarter-wavelength stub, a first cylindrical capacitor, a second cylindrical capacitor and a lightning suppression circuit. Each of the cylindrical capacitors has an inner conductor element, an outer conductive tube and a dielectric material. Direction coupler acts to block direct current and low frequency signals from passing therethrough. The quarter-wavelength stub comprises a helicoid and acts to reflect radio frequency signals back to the transmission line while allowing direct current and low frequency signals to flow therethrough. First cylindrical capacitor and second cylindrical capacitor combine to form a low pass filter which allows direct current and low frequency signals to flow through while blocking other signals. The lightning suppression circuit suppresses high voltage direct current and low frequency signals such as those produced by near lightning strikes.

Abstract: An electronic circuit device having a power wiring resonance inhibition function includes a plurality of electronic circuit elements, and a wiring board having the electronic circuit elements disposed thereon. The wiring board includes a plurality of planar power supply wires for supplying power to the electronic circuit elements. The planar power wires include a pair of planar power supply wires for supplying power to the electronic circuit elements at a predetermined voltage. The electronic circuit device also includes a plurality of damping elements disposed at a plurality of positions on the wiring board. The damping elements are connected between the pair of planar power supply wires at a plurality of positions on the pair of planar power supply wires. The damping elements reduce power supply system impedance and inhibit power wiring system resonance, thereby reducing supply voltage fluctuation caused by the power wiring system resonance and noise caused by the supply voltage fluctuation.

Abstract: The steep initial rate of rise of the transient recovery voltage across the poles of a circuit breaker just after a fault current break is decreased. The breaking performance in the case of a short-circuit fault to ground taking place in an electrical power transmission system at relatively as near a place as several kilometers apart from the circuit breaker, that is a short-line-fault is improved by a saturable reactor having a capacitor connected in parallel therewith to the circuit breaker in series. As a result, as the saturable reactor changes from the magnetically saturated state to the unsaturated state just before the zero point of the fault current, the self-inductance of the saturable reactor gradually increases and an LC resonance is produced between the self-inductance of the saturable reactor and the capacitor connected to the saturable reactor in parallel.

Abstract: A radio frequency identification (RFID) tag includes a tank circuit for receiving a power signal transmitted on a radio frequency (RF) carrier by a remote interrogator unit. Information is conveyed from the tag to the interrogator by varying a resistive load placed across the tank circuit as a function of data read from memory. Corresponding variations in the reflected signals are then detected by the interrogator. An overvoltage circuit cooperates with a modulation circuit for providing transmission of data even during an overvoltage condition, thus avoiding masking of the signal under such conditions.

Abstract: 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.

Abstract: Combination coaxial surge arrestor and power extraction apparatus for providing overvoltage protection for a coaxial transmission line carrying both an RF signal and AC power and for extracting AC power from the coaxial transmission line. The surge arrestor comprises a coaxial gas discharge tube with a center conductor and a conductive body. The apparatus includes an inductor for extracting the AC power, the inductor having a high reactance at the frequency of the RF signal and a low reactance at the frequency of the AC power, and a capacitor for passing the RF signal, the capacitor having a low reactance at the frequency of the RF signal and a high reactance at the frequency of the AC power.

Abstract: An electrical impulse suppressor comprising a band pass filter formed with strip transmission lines adapted to attenuate the flow of energy therethrough above and below a band limited range of frequencies. The suppressor used the impedance of a discharge means connected to a strip transmission live element to form the first of two resonant circuits used in the construction of the band pass filter.

Abstract: 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.

Abstract: A circuit interrupter including an improved arc detection system which trips the interrupter in response to currents having frequencies and/or characteristics associated with arcing within the associated alternating current electrical system. The arc monitoring circuit determines if the signal produced by a current transducer is the result of arcing. The arc detection system includes two swept filters and associated amplifiers which produce a signal which has an amplitude representative of the frequencies present in the alternating current of the electric system. The portion of the filtered signal which has amplitudes above a predetermined level is integrated to produce a trip signal for the circuit interrupter when the value of the integration exceeds a predetermined limit.

Abstract: Filter equipment is adapted for connection to an ac power network (N) for damping of current harmonics originating from an installation (TR, SR1, SR2), connected to the network, for power transmission by means of high-voltage direct current. The equipment has a three-phase filter set (F) with three filter branches which are each normally connected to a separate phase of the network via first switching members (BO). A spare filter branch (FR) is arranged as a stand-by for the three filter branches of the filter set (F) and is adapted for connection to an optional phase of the network by means of second switching members (BR).

Abstract: A small-sized arrangement for a DC circuit breaker with a reactor and a capacitor connected in series is provided which includes a DC circuit breaker, a parallel impedance means with a suitably determined inductance and a suitable capacitance less in value than the inductance, and an energy-absorbing element. The parallel impedance means has a parallel reactor of a carefully selected inductance and a parallel capacitor of a smaller capacitance value. Determining the inductance and capacitance values of the parallel reactors and parallel capacitors employed in the parallel impedance means to satisfy a certain condition defined by specific formulas can cause the DC circuit breaker to take full advantage of the inherent performance thereof while allowing the interruption time to remain minimized, thereby achieving enhanced interruption performance. Since the capacitance of the parallel capacitor is rendered relatively smaller, the device can be small in size and low in cost.

Abstract: A transformerless conditioner of a power distribution system consists of an electronically enhanced filter (EEF) for suppression of transient impulses on the power line and neutral line, and a transformerless ground conditioner for suppression of transient impulses on the ground line. The filter includes a normal mode filter having an inductor located on the power line and an inductor located on the neutral line between source and load of the power distribution system, and a pair of capacitors arranged in series and connected between the power and neutral lines, whereby a midpoint tap is formed between the pair of capacitors. The EEF also includes a unique common mode filter which is formed by the series connection of either inductor of the power line or the neutral line, or both, to its corresponding capacitor and then to the midpoint, from which an electronic impulse detector is connected to ground.

Abstract: An improved surge arrestor for RF devices includes a bifilar conductor pair wound around a ferrite core wherein one end of each conductor is grounded. The energy of RF signals input to the surge arrestor from an RF transmission line is transferred from the primary windings to the secondary windings through the magnetic coupling. When an electrical transient or fault causes a surge on the input or primary side of the surge arrestor, the core becomes saturated, thereby limiting the amount of energy transferred to the secondary windings and the RF device. This effectively isolates the secondary side of the surge arrestor from the damaging surge in voltage and prevents the secondary side from conducting the surge to electronic components within the RF device.

Abstract: A device for measuring circuit breaker wear by integrating the square of the current to be interrupted, said circuit breaker including a control that is actuated by a trip coil. The device includes a timing delay circuit that is actuated by a signal corresponding to a change in the driven or non-drive state of the trip coil, the timing delay circuit causing integration to begin after time has elapsed that is equal to the mechanical delay of the circuit breaker, which mechanical delay is a previously-measured data item. The device further includes a circuit that delivers a signal proportional to the current carried by the circuit breaker, a circuit that squares the signal, and that applies said square to the integrator, said integration being performed for a given length of time that is longer than the maximum arcing time of the circuit breaker, which maximum arcing time is likewise a previously measured data item, the result of the integration being applied to a summing circuit.

Abstract: A sensor arrangement for producing a signal representative of currents having frequencies and/or characteristics associated with arcing within an alternating current electrical system. The arrangement is coupled to an appropriate arc monitoring circuit which determines if the signal produced by the sensor is the result of arcing within the electrical system. One embodiment of the sensor arrangement includes an inductor, and a capacitor connected in series with the primary winding of a transformer. The inductor is typically connected in series with a phase conductor of the electrical system, and the capacitor and the primary winding are connected to the phase conductor in parallel to the inductor. Another embodiment of the sensor arrangement includes a capacitor and the primary winding of a transformer connected in series between the phase conductor of the electrical system and either a ground or neutral conductor of the system.

Abstract: Described is an active filter (10) for removing harmonic currents from a neutral wire (24) to reduce the current I.sub.n in the neutral wire. The filter (10) typically is located away from the source (26) and near the load (28). The filter (10) comprises generally a multi-phase transformer (12), a neutral current monitoring device (14), and a harmonic current injection device (16). The components of the present invention operate to draw a corrective harmonic current (I.sub.N) from the neutral wire (24) at a tap point (T) near the load (28) and inject the corrective harmonic current (I.sub.N) through the multi-phase transformer (12) into the phase wires (20). The corrective harmonic current (I.sub.N) substantially cancels the harmonic current (I.sub.n) in the line on the source side of the tap point (T) and therefore eliminates over-current conditions in the neutral wire. The device preferably includes a rectifier (36) connected by the secondary windings (34) of the transformer (12) to power a DC bus (38).

Abstract: A protection arrangement for an electronic device sensitive to electromagic radiation comprises a single printed circuit board which is disposed within a metal casing so that it passes perpendicularly through a metal partition separating an upstream zone in which electromagnetic fields prevail from a screened downstream zone, the board thus having a first part situated in the upstream zone and a second part, which is intended to carry the electronic device, situated in the downstream zone. Electrical signals are conveyed from the upstream zone to the downstream zone by means of conductive lines printed on at least one inner layer of the printed circuit board, and the board is provided with means for filtering the electrical signals comprising surface-mounted components in the vicinity of the metal partition and capacitive elements integrated in the printed circuit board where it passes through the partition.

Abstract: A method and a device for measuring compensation balance and imbalance in an electrical supply network having a balancing coil. An auxiliary measurement signal is injected into the network's neutral circuit, changes in the homopolar voltage induced by the auxiliary signal injection are measured, and an impedance measurement is obtained by comparing the changes in the hompolar voltage with the injected auxiliary measurement signal, in terms of both amplitude and phase. A parallel current may advantageously be injected into the neutral circuit at the secondary winding of a homopolar transformer placed in the neutral coil.

Abstract: The present invention is directed to a system for sensing fault current flowing through a person who touches an exposed conductor in a cable connecting a machine to a power distribution center wherein the power distribution center has a number of power cables for connecting a number of machines thereto. Each power cable has a different frequency impressed thereon by an oscillator which frequency is transmitted through an electrical path including the power center if the operator touches the fault. A sensing circuit for each cable is connected in the electrical path and tuned to only the frequency applied to that cable. When the sensing circuit detects that frequency, the sensing circuit interrupts power to the cable. If, for some reason, the sensing circuit fails to interrupt power to the cable, within a selected time interval of less than one-half second, a backup system interrupts power to the entire power center.

Abstract: A system of protection which utilizes a simple circuit for the detection and isolation of single and multiple phase to phase and phase to neutral faults between a multi-phase source of electrical energy and a power conversion device driven therefrom. The circuit comprises a current transformer positioned at the neutral aspect of each phase winding of the multi-phase source of electrical energy. These current transformers sense the current generated by the source of electrical energy and produce a signal of proportional magnitude thereby. These proportional sense signals from each of the individual current transformers are transmitted to a controller which vectorially adds these signals to produce a single summed output signal. The controller monitors the percent ripple content of the summed output signal and generates an output protection signal if the percent ripple content of the monitored summed output signal exceeds a predetermined threshold value for a predetermined time interval.