Abstract: A device for measuring alternating current in a conductor comprising an even number of identical coils (C1) to (C14) mounted on an electrically insulating coil support member (10). Half the coils (C1) to (C7) are equally spaced around a first notional circle and are connected in series by a first conductive track (12) and the other half of the coils (C) to (C14) are equally spaced around a second notional circle, concentric with the first, and are connected in series by a second conductive track (14). The support member (10) has a recess (16) to allow a conductor under test to be introduced into the centre of the concentric circles. The device further includes means (R1, R2, 20) for deriving the alternating current in the conductor as a function of the voltages induced in the first and second sets of series-connected coils. The coils (C1) to (C14) and the support member are manufactured by printed circuit or thick film technology.

Abstract: The method described here makes it possible to determine the impedance of a line (1) by measuring the voltage (u) applied across the line and the time derivative of the current (i) flowing through the line. The measured values of the differentiated current are not integrated in this case, but rather are substituted directly, together with the measured voltage values, into an equation system from which the values of the inductance (L) and the resistance (R) of the line (1) can be estimated. In this way, integration of the values of the differentiated current is obviated.

Abstract: A current sensor (1) is provided with low-pass filters (17 and 18) for stabilizing the pulse-duration modulated compensation signal. The current sensor is also provided with an additional RC element (40). Furthermore, a limiting means consisting of Zener diodes (44) and an ohmic resistance (45) is provided for suppressing fast current transients.

Abstract: An electrical quantity sensor includes, an oscillation circuit for producing a clock signal of predetermined frequency, a light-emitting element which blinks at a predetermined frequency in accordance with the clock signal output from the oscillation circuit, a switching element which is optically coupled to the light-emitting element and is brought into conduction when the light-emitting element illuminates, a transformer whose primary winding is connected, by way of the switching element, to input terminals which receive a d.c. electrical signal and a synchronization detecting circuit which synchronously detects an a.c. electric signal developing in a secondary winding of the transformer while the clock signal is taken as a reference, thereby producing a d.c. voltage signal corresponding to the amplitude of the d.c. electric signal.

Abstract: A system and method for testing an on-line current transformer is provided. The current transformer includes a primary winding and a secondary winding. An operating current continues to flow through the primary winding during testing of the current transformer. A controllable load is applied to the current transformer secondary winding. The controllable load is varied over a range of load settings including a maximum current setting and a maximum voltage setting. At a plurality of load settings within the range of load settings, a current flowing through the current transformer secondary winding is measured. Also, a voltage across the current transformer secondary winding is measured. An actual excitation curve is generated from the measured currents and voltages corresponding to the plurality of load settings.

Abstract: A coil includes a first portion, a second portion, a third portion, and a fourth portion. The first portion is wound in a first direction around a first core and the second portion is wound in the first direction around a second core. The third portion is wound in a second direction that is different from the first direction around a third core such that the third portion is decoupled from the first and second portions. Additionally, the fourth portion is wound in the second direction around a fourth core and decoupled from the first and second portions. An inner area is formed by arranging the portions and a voltage is induced in the coil if an electrical conductor is placed in the inner area.

Abstract: An alternating current detector includes a current transformer having a primary winding through which a current to be detected flows, and a secondary winding and an auxiliary winding, magnetically coupled to the primary winding via a core, of which one ends are connected to each other and thus form a common terminal, and an operational amplifier for amplifying a voltage induced in the auxiliary winding, and applying the voltage to the secondary winding with the current assuming such a polarity as to restrain a change in magnetic flux of the core, whereby a voltage corresponding to the current to be detected is induced in the secondary winding. A waveform of a large current having a low frequency can be thereby observed highly precisely with an output of the detected voltage having a large amplitude.

Abstract: A method and/or apparatus for measuring current in a high voltage (HV) current carrier generates a low voltage signal proportional to the current in the HV carrier and applies this signal to an integrated-optic voltage sensor located in the HV environment adjacent to the HV current carrier to produce a modulated optical signal representative of the current being measured. The optical signal from the integrated-optic voltage sensor is conducted to a low voltage (LV) environment insulated from said HV environment and processed to provide a second electrical signal. One of the electrical signals is integrated so that an output signal of the required accuracy is available form the system.

Abstract: A voltage and current sensor comprised of a plurality of surface mounted inductors serially connected around the circumference of a current carrying conductor and a plurality of surface mounted resistors each connected in parallel with an inductor wherein an electrical circuit connected to the inductors and resistors provide a measurement of current in the conductor. The inductors and resistors are mounted on a printed circuit board that has a plated aperture for receiving the current carrying conductor there through. An electrical circuit connected to the plated aperture provides a voltage measurement.

Abstract: A wideband precision current sensor employs DC-coupled and AC-coupled sensing circuits to generate lower and higher frequency sense signals; which are combined to form a wideband output signal that is proportional to a wideband current of interest. The frequency response of the wideband output signal is substantially flat across a wideband frequency range, 0 to 30 MHz for example, based on matching the frequency response of the DC- and AC-coupled sensing circuits. In an exemplary application, the current sensor provides feedback to a supply voltage (Vdd) amplifier used in RF envelope elimination and restoration (EER) applications.

Abstract: A test method characterizes current behavior of power components (e.g., semiconductor packages) within an electronic system. One or more electrically conductive loops are formed with a first printed circuit board of the electronic system; these loops surround, at least in part, one or more electrical vias of the first printed circuit board. One or more power components connect to the vias to obtain power therethrough. Current characteristics are measured from one or more vias to assess transient and steady-state currents of components within the system. Power dissipation may be determined from the current. The loops may be formed within tracks of internal layers of the first printed circuit board, or a second printed circuit board may form the tracks.

Abstract: Monitoring a leakage current from an isolator for a high voltage conductor to ground includes directing the leakage current through a primary wire inductively coupled to a secondary winding energizing an amplifier.

Abstract: Disclosed herein is a probe for measuring voltage/current of a low voltage power distribution cable. A probe has a body having a first opening and a first recess and made of an insulating material. A lower core is inserted into the first recess of the body, and a coil is wound around an insulating material installed at the lower core for detecting an induction current. A capacitor and a resistor are connected between output lines extended from the coil so as to filter out noise components, and a ground line is electrically connected to one end of the lower core. A voltage detection terminal is electrically connected to the low voltage power distribution cable for detecting voltage applied to the low voltage power distribution cable. A voltage output line is used for outputting the detected voltage. A connector is connected to output sides of the output lines extended from the coil, the ground line and the voltage output line.

Abstract: A current sensor for measuring a time-varying electrical current (Im) in a portion of primary conductor (1), the sensor including a sensor conductor comprising first and second ends (3,4) for connection to a signal processing circuit, a first conductor portion extending from the first end and having a plurality of windings (5) to form a first coil portion, and a second conductor portion returning to the second end. Centres of the windings define a median coil place substantially parallel to the magnetic field (Hm) generated by the time-varying current (Im) to be measured, the sensor conductor defining one or a plurality of interference field surfaces as seen projected on a plane parallel to the median plane enclosed by clockwise or anti-clockwise interference field current circulating portions (22,23) of the sensor conductor.

Abstract: Disclosed is a method for detecting saturation of a current transformer. The method determines whether or not a change of a secondary current generated in a current transformer is due to the saturation of the current transformer.

Abstract: A current measuring device comprising a Rogowski coil (30). Connected across ends of the coil (30) is a passive integrator in two parts (34, 36), the parts being connected by a coaxial cable (32). Connected to the output of the passive integrator (34, 36), is an electronic integrator (38). At low frequencies the passive integrator (34, 36) has a substantially constant gain and the electronic integrator (38) integrates the signal from the coil (30). At high frequencies, the electronic integrator (38) has substantially constant gain and the passive integrator (34, 36) integrates the signal from the coil (30). In order to reduce high frequency voltage oscillations, the Rogowski coil (30) is terminated with a coil damping resistor that has a value that is approximately the same as a characteristic impedance of the coil.

Abstract: A coil includes a first portion, a second portion, a third portion, and a fourth portion. The first portion is wound in a first direction around a first core and the second portion is wound in the first direction around a second core. The third portion is wound in a second direction that is different from the first direction around a third core such that the third portion is decoupled from the first and second portions. Additionally, the fourth portion is wound in the second direction around a fourth core and decoupled from the first and second portions. An inner area is formed by arranging the portions and a voltage is induced in the coil if an electrical conductor is placed in the inner area.

Abstract: The device comprises modelling means representative of an inverse model of the current transformer. These modelling means receive on input the instantaneous values of the secondary current measured in a first secondary winding of the current transformer and, by means of an integrator, the integral of the secondary voltage measured at the terminals of a secondary winding of the current transformer. The modelling means supply on output the instantaneous values of the associated primary current, corrected in case of saturation of the transformer. The secondary voltage can be supplied by the first secondary winding or by an additional second secondary winding, arranged around the first one.

Abstract: A system and method for detecting a concealed current carrying conductor is presented. A first and a second field strength signal proportional to an electromagnetic field is generated. A value is determined for the first field strength signal. This value is used to divide the second field strength signal and form an indicator signal. A value for the indicator signal is determined. If the value of the indicator signal is equal to or greater than a predetermined value (i.e., not less than the predetermined value), a conductor detection signal is generated and used to alert a user to the presence of a concealed current carrying conductor.

Abstract: An arc fault detector for detecting electric power lines includes a current transformer preferably in the shape of a toroid, with a neutral conductor and at least one line conductor passing through the aperture of the toroid. The sensor has two multi-turn windings each formed around a portion of the toroidal core, with one winding adjacent to each of the hot and neutral wires respectively, with both windings connected in series in a way which re-enforces arc fault noise generated by arc faults involving the line and neutral, but which causes signal reduction for noise signals from the line and neutral, or either, to ground. The windings and core are also selected to self resonate at a frequency or over a band of frequencies that excludes power line carrier frequencies but which includes arc fault frequencies.

Abstract: A parameter monitoring apparatus for a high voltage chamber in a semiconductor wafer processing system monitors parameters in the high voltage chamber in real time by converting an electrical signal generated from the high voltage chamber into an optical signal using an electro-optical converter. The optical signal is then converted back into an electrical signal again by an opto-electrical converter. The parameters can be monitored in real time without damaging measurement devices, since they are not influenced by the potential difference between the high voltage chamber and the measurement device.

Abstract: The exciting current of a current transformer is calculated and added to the measured secondary current to produce a corrected signal. The exciting current is calculated by first calculating the current transformer induced voltage. The induced voltage is calculated from a parameter related to secondary current and known characteristics of loop impedances through which secondary current flows. The parameter related to secondary current may be the secondary current itself, or a voltage associated with secondary current flowing through an impedance. The calculated induced voltage is then applied across an inductor having similar magnetic properties as the current transformer. By scaling the applied voltage properly, the current flowing in the inductor is approximately proportional to the exciting current of the current transformer. The current in the inductor is measured, and, by applying an appropriate constant of proportionality, the exciting current of the current transformer is determined.

Abstract: An invention including an outer shell that can be used to provide separated conductors and a method for installing a conductor in the outer shell is disclosed. The invention can assume many different embodiments. The outer shell is adapted to retain a conductor and includes a base adapted to associate with a support surface. The outer shell also includes a hollow sensing portion that extends from the base and is adapted to retain a conductor. The sensing portion is spaced from the base a distance sufficient to accommodate a portable, hand-held current sensing device. The invention also includes a method of installing a conductor in the hollow sensing portion.

Abstract: Aspects for detecting current flow in a power line cord are described. In these aspects, a line current detector circuit is provided for each input plug line of a power distribution box. A determination of whether line current is flowing in a system line cord plugged into the power distribution box is based on a light indicator from the line detector circuit. The line current detector circuit includes a magnetic device for detecting line current flowing in a power line cord, and a light emitting diode (LED) coupled to the magnetic device for outputting a light indicative of whether current is flowing in the power line cord.

Abstract: An apparatus for sensing electrical current flowing in a conductor includes a toroidal core formed of a ferric material and having a slot defining an air gap, a Hall Effect sensor integrated circuit positioned in the air gap for sensing electrical current flowing in a conductor received in a central aperture of the core, and a housing enclosing the core and the integrated circuit. The integrated circuit can be programmed to set functions such as output offset, gain, temperature compensation and a current sensing range.

Abstract: An apparatus for measuring high frequency currents includes a non-ferrous core current probe that is coupled to a wide-band transimpedance amplifier. The current probe has a secondary winding with a winding resistance that is substantially smaller than the reactance of the winding. The sensitivity of the current probe is substantially flat over a wide band of frequencies. The apparatus is particularly useful for measuring exposure of humans to radio frequency currents.

Abstract: The invention relates to an apparatus and method for load testing electrical systems using a transformer having its primary windings connected to a power source and its secondary windings coupled to the device under test. The test apparatus may be used to test high power switching circuits to be implemented in three-phase power systems. One aspect of the invention involves eliminating the load resistor or load bank, which is normally used to simulate the working load when testing AC switching devices. In one embodiment, the load bank function is replaced by the secondary winding of a step-down transformer, and the voltage across the device under test is boosted using a second power source. In another embodiment, the primary current of the transformer is controlled to regulate the current in the device under test.

Abstract: The invention relates to sensors for detecting a time-varying current by employing a plurality of coils with separate windings, disposed on separate toroidal cores, that are placed in close proximity of each other so that each coil responds independently to the same current. The current produces a time-varying magnetic field which in turn induces a plurality of voltages across the coils that can be combined to provide a resultant signal. Some embodiments of the invention employ coils with opposite windings to obtain signals with opposite phases and combine these signals through differential detection means to obtain a combined signal. One aspect of the invention relates to production of a wide-band or a selectable band-width sensor by preparing at least one coil to be dissimilar with respect to the others. In addition, the invention provides provisions for easy calibration of the sensor.

Abstract: The method of correcting measurements is intended to limit the risk of unnecessary tripping of a differential phase current protection system that computes the vector sum of the currents of an area to determine the differential current between the inputs and outputs of said area in the course of regular tests. It is based on a statistical balancing method using measured current vectors each obtained from a measurement of the real current vector supplied at the time of each test by a current transformer, and it uses at the time of at least one test an iterative convergence algorithm for determining from the erroneous differential current vector formed by the sum of the measured current vectors the correction vector to be applied to each measured current vector in order to correct statistically the erroneous differential current vector.

Abstract: In power circuit breakers including a current transformer with a current detection coil without any iron and including an integration circuit connected downstream from the current detection coil, the unavoidable time constant of the integration circuit can lead to spurious trappings. This is avoided by a method in which the instantaneous values of the current are detected and stored at defined periodic intervals. The stored measured values are compared on the basis of polarity and magnitude. If it is found that the stored values have the same polarity and fall monotonally, it is assumed that the DC element is originating from the integrator and a tripping inhibit signal is set in the electronic release of the power circuit breaker.

Abstract: A system and method for measuring at least one characteristic of a power line supported by a power line pole includes a pin having a first end coupled to the pole and a second end adapted to engage a sensor, wherein the sensor measures at least one characteristic of the power line and an insulator coupled to the second end of the pin supports the power line. The close proximity of the sensing element to the conductor immerses the sensor in the strong magnetic field close to the current carrying conductor to provide low cost accurate current measurement capability.

Abstract: An electrical quantity sensor includes, an oscillation circuit for producing a clock signal of predetermined frequency, a light-emitting element which blinks at a predetermined frequency in accordance with the clock signal output from the oscillation circuit, a switching element which is optically coupled to the light-emitting element and is brought into conduction when the light-emitting element illuminates, a transformer whose primary winding is connected, by way of the switching element, to input terminals which receive a d.c. electrical signal and a synchronization detecting circuit which synchronously detects an a.c. electric signal developing in a secondary winding of the transformer while the clock signal is taken as a reference, thereby producing a d.c. voltage signal corresponding to the amplitude of the d.c. electric signal.

Abstract: A device comprises a first magnetically conductive structure, a second magnetically conductive structure, and a circuit coupled the first and second magnetically conductive structures. The circuit senses information pertaining to a permeability of the first magnetically conductive structure relative to a permeability of the second magnetically conductive structure. The device may be used for various flux sensing and control applications, such as in current sensors.

Abstract: A Hall-effect sensor package for sensing electrical current in an electrical conductor, is provided which includes a ferromagnetic core having an air gap, the core allowing for the electrical conductor to pass therethrough. The sensor package also includes a Hall-effect generator, at least a portion of the Hall-effect generator being located within the air gap, and a lead frame coupled to the Hall-effect generator. An insulative material is used to encapsulate the Hall-effect generator and at least a portion of the core and the lead frame. The insulative material facilitates binding of the Hall-effect generator, the lead frame and the core. The insulative material also facilitates protecting the Hall-effect generator from contaminants.

Abstract: The invention relates to a method for determining a value of a current using a current transformer that operates in the core saturation region. A peak value detector determines a peak value of one half-cycle of the secondary current. The peak value is stored in a storage element for further processing. A comparator detects that the peak value has been reached. After this, the comparator supplies a switching signal to a signal processing unit, and this signal starts the signal processing unit. The signal processing unit receives the peak value that was stored in the storage element and provides this value for further processing. A RESET pulse is then transmitted to a switching apparatus to discharge the storage element and thus allow the detection of the next peak value.

Abstract: A clamp for measuring an electric current flowing in conductors, the clamp comprising first and second jaws (1, 2) interconnected by a hinge axis (3) to be movable between a closed position and an open position, the jaws being provided respectively with first and second annular magnetic circuit segments (4, 5), each segment (4, 5) having a proximal end (7, 8) and a distal end (9, 10) relative to the hinge, and at least the first segment (5) being mounted to rock about a rocker axis (6) parallel to a hinge axis (3), the clamp including spacer means (12) for spacing the proximal ends (7, 8) apart, which spacer means are active at least when the distal ends (9, 10) are spaced apart by a distance that is greater than or equal to a predetermined safety distance.

Abstract: Disclosed is a method for detecting saturation of a current transformer. The method determines whether or not a change of a secondary current generated in a current transformer is due to the saturation of the current transformer.

Abstract: An invention including separated conductors is disclosed. The invention can assume many different embodiments. The invention includes a chassis or body adapted to receive a first conductor and second conductor, the first conductor being separated from the chassis and the second conductor a distance sufficient to accommodate a portable, handheld current-sensing device. The first conductor has an insulating jacket and is generally less flexible than the flexibility of the first conductor without the insulating jacket. In addition, the invention preferably does not influence the current flow through the apparatus and the invention continues to provide electricity even if the current detector malfunctions.

Abstract: A dual totem (or H-bridge) power stage has four power devices, at least two of which are controlled by pulse width modulation (PWM) control signals to change current paths of the load current flowing through the driven load. A current sensor for measuring the load current includes a transformer having a secondary winding having a number N of turns, and a primary winding. The primary winding has four separate primary winding sections each coupled in series with a different one of the four power devices of the dual totem power stage. Different ones of the four primary winding sections have different numbers of turns such that different turns ratios result between the primary winding and the secondary winding for different current paths, thus generating a modulated signal on the secondary winding. The modulated signal is demodulated for accurate representation or reproduction of the current flowing through the load.

Abstract: The present invention provides a current sensor for an electrical device. The sensor includes a housing, a conductor routed through the housing, an array of current transducers coupled to the conductor, and a current level signal generated by the current transducers. The conductor is adapted to be connected in a current path of the electrical device. Each of the current transducers has an output lead. The current level signal is provided on said output leads. The output leads are electrically connected to a printed circuit board. An external connector is electrically connected to the printed circuit board through a cable. A plurality of shields are used adjacent to the current transducers. The array of current transducers can be a single layer array, a multiple layer array, or a planar array.

Abstract: A method and apparatus for measuring quantities of a multi-phase electric line, the apparatus comprising a control unit (7) and a measurement unit (4, 5, 6) in connection with each phase conductor (1, 2, 3) of the electric line, wherein each measurement unit is arranged to measure a first phase quantity of the phase conductor in connection with which it is located and to transfer the measured quantity value to the control unit (7), the measurement unit located in connection with one phase conductor being further arranged to measure phase angles between the first phase quantity of said phase conductor and first phase quantities of other phase conductors and to transfer the measured phase angle values to the control unit (7).

Abstract: An electric noise absorber for preventing looseness of magnetic body parts in a closed housing, without increasing the number of parts or decreasing the strength of the housing. The housing comprises a pair of case halves which house ferrite core halves, respectively, and are hinged to each other. The bottom wall of each case half is formed with a curved shape convex toward the space housing the ferrite core half. When the case halves are closed with the ferrite cores therein, the ferrite cores press each other toward respective bottom walls and resiliently deform the walls. The resilience of the deformed bottom walls urges abutting surfaces of the ferrite cores into close contact.

Abstract: An active load or source impedance synthesis apparatus for experimental characterization of electronic components (E) working in the range from 500 MHz to 110 GHz, includes an active loop with at least one amplifier (Am), one magnitude and phase control system (Ra, Rs, one directional coupler (Acc) and a measurement system connected to a device under test (E), where the directional coupler (Acc) is connected after the most significant losses of the measurement system.

Abstract: A clamp for measuring an electric current flowing in conductors, the clamp comprising first and second jaws (1, 2) interconnected by a hinge axis (3) to be movable between a closed position and an open position, the jaws being provided respectively with first and second annular magnetic circuit segments (4, 5), each segment (4, 5) having a proximal end (7, 8) and a distal end (9, 10) relative to the hinge, and at least the first segment (5) being mounted to rock about a rocker axis (6) parallel to a hinge axis (3), the clamp including spacer means (12) for spacing the proximal ends (7, 8) apart, which spacer means are active at least when the distal ends (9, 10) are spaced apart by a distance that is greater than or equal to a predetermined safety distance.

Abstract: A method and apparatus for simultaneously measuring voltage and current in a primary high voltage conductor. A current and a voltage from the primary conductor is monitored. The current and voltage information present on the current transformer secondary winding is separated. The voltage information present on the current transformer secondary winding is used to provide a voltage measurement output proportional to the voltage present on the primary conductor. The current information present on the current transformer secondary winding is used to provide a current measurement output proportional to the current flowing on the high voltage conductor.

Abstract: A current measuring element comprising a current carrying conductor having the shape of a flat rail in an insulating housing and a hall sensor which is arranged in the proximity of said conductor. The current carrying conductor is bent to form a unshaped conductor loop in the area of the hall sensor and the hall sensor is situated on a board which is arranged in the unshaped conductor loop. The board containing the hall sensor is placed upon a main board on which the signal from the hall sensor is processed. An insulating cover provided for the housing is arranged between the housing containing the current carrying conductor and the main board. The cover comprises an insulating compartment which extends inside the conductor loop and receives the board containing the hall sensor.

Abstract: A current sensor and current transformer for monitoring electrical current is provided with a magnetic core having a mixture of magnetic materials to provide a low cost design in a compact configuration with an expanded dynamic range. The mixed material core can be fabricated either from stamped laminations or from coil stock and may include an air gap for activating a magnetic flux sensor. Multiple core configurations, including Figure-O, Figure-C, and Figure-8, having mixed material construction are disclosed and offer advantages over non-mixed material cores where dynamic range and frequency response characteristics are a consideration.

Abstract: A current sensor according to the present invention comprises a multilayer substrate comprising two or more layers, a through-hole provided to pierce the multilayer substrate from the front face to the rear face, a coil formed by connecting a wiring on the front face with a wiring on the rear face via the through-hole, and a wire pattern arranged so as to thread through the coil. When a current is applied to the wire pattern, the current sensor detects a voltage generated at both ends of the coil.

Abstract: A method permits calibration of a current sensor having a conductor that comprises at least two conductor branches electrically connected in parallel. The method comprises passing a predetermined electrical current through the conductor, measuring a fraction of the current that passes through a measured conductor branch, which is one of the two conductor branches, comparing the measured current against a predetermined target current, trimming a calibrating conductor, which is one of the at least two conductor branches, the trimming taking place when said measured current and said predetermined target current are not equal.

Abstract: Disclosed herein is a hand-held clamp-type multi-meter capable of measuring current and other electrical characteristics. The clamp includes a hinged jaw which is openable in the current detecting mode of the multi-meter, but not in other modes.