Abstract: A device for measuring an electric quantity such as electric current flowing in an electric equipment unit, which device is in a case fitted on a mounting support, and having pass-through holes and terminals separated by insulating material, their number corresponding to the number of phases of the equipment unit, the holesto permit a conductor to pass therethrough, to be electrically connected to strips of terminals of the equipment unit the opposite end to electric contact strips of a load-side or line-side apparatus from the equipment unit and, for at least one terminal of the device, a magnetic core at least partially surrounding such terminal with an air-gap around which a secondary measuring coil is wound between two end portions of the magnetic core which define the air-gap, the coil(s) delivering a signal representative of the current flowing in the apparatus.

Abstract: A clamp-on multimeter measures alternating current flow in an electrical conductor. The multimeter includes a display, a housing including the display, a first sensor, a second sensor, a processor and an integrator. The first sensor has a magnetizable material core and inductively senses the alternating current. The first sensor includes a first clamp portion fixed to the housing and a second clamp portion pivotally coupled to the first clamp portion. The second sensor includes a Rogowski coil that has a non-magnetic core and inductively senses the alternating current. The processor receives an input signal in a first voltage range and sends an output signal to the digital display. The integrator scales a signal from the second sensor in a second voltage range to the first voltage range. The housing includes the processor, the integrator, and a selector configured to select the input signal to the processor from one of the first sensor and the integrator.

Abstract: A method includes measuring a first voltage (VA) across a first sensing coil of a linear variable differential transformer (LVDT) and measuring a second voltage (VB) across a second sensing coil of the LVDT. The method also includes signaling a core fallout condition in response to (i) determining that a ratio of VA and VB is within a specified range of a value of one and (ii) determining that a sum of VA and VB is less than a sum of VA0 and VB0 by more than a specified amount. VA0 and VB0 are minimum voltages across the first and second sensing coils of the LVDT, respectively, when a core of the LVDT is in the LVDT.

Abstract: A zero-phase current is outputted by detecting a ground-fault current with a zero-phase-sequence current transformer. A circuit having an open collector output operates when the voltage of the zero-phase current exceeds a positive side threshold value or it falls below a negative side threshold value to discharge a capacitor. When the inter-plate voltage of the capacitor falls below a threshold value voltage, a controlling means detects electric leakage to transmit that to a control unit of an air conditioner.

Abstract: This aims to provide a diagnosing device for detecting the measurements of an electric current, a voltage and a resistance by a temperature/moisture or pressure sensor or a signal state in control means, precisely with a simple circuit constitution, for diagnosing the soundness of a circuit while simplifying a power source circuit, to suppress the cost more than the conventional circuit having no diagnosing function, and for diagnosing the signal status in the measurement or control by a measuring means or a control means. An alternating voltage generating means containing a pulse-wave voltage and an alternating current is connected with the primary side of a transformer, and a driven member such as the measuring means for any of varying electric current, voltage and resistance is connected with the secondary side.

Abstract: A device for measuring the intensity of an electric current which has a simple and economical design and offers a high measurement dynamic compatible with combined measurement, protection and energy metering applications. The device (1) is insensitive to parasitic fields and to the position of the electric conductor to be measured, and that can be opened to facilitate placement thereof. The device (1) defines a closed path (C), about a conductor (2) for the circulation of the lines of magnetic field induced by the current to be measured, and the path is formed by two plates (30) having a high magnetic permeability separated by two air gaps (E) closed by two identical and opposed electric coils (4) for supplying a voltage proportional to the derivative of the intensity (I) of the current to be measured. The device (1) reduces the is compact so that it can be easily integrated into any type of electric appliance.

Abstract: According to one aspect, embodiments of the invention provide a current monitoring device comprising a current transformer configured to be removeably coupled to a power line and to generate a reference signal having a level related to a current level of the power line, a sensor circuit connected to the current transformer and configured to be removeably coupled to a communications bus and to convert the reference signal to a digital reference signal and provide a signal indicative of the current level to the communication bus, and a housing containing the sensor circuit and the current transformer.

Abstract: A power monitoring system that reduces the need for external power calculation devices while simplifying the configuration of power meters.

Abstract: The present invention relates to a device for current measuring in power supply networks comprising transformers for measuring current, a signal processing apparatus arranged on a printed circuit board and screw fastenings for mounting the device. The cable ducts of the transformers are orientated parallel to the plane of the printed circuit board, which has openings flush to the cable ducts, and the screw fastenings are fastening tabs with mounting holes, spaced so standards-compliant mounting is possible. In an alternate embodiment, the cable ducts are orientated perpendicularly to the plane of the printed circuit board, the screw fastenings are constructed as an angle rail with cable outlets and standards-compliant mounting holes, and the printed circuit board is internally fastened on one side of the angle rail. In another alternate embodiment the transformers are installed with the printed circuit board in a common housing with fastening tabs and standards-compliant mounting holes.

Abstract: A faulted circuit indicator (FCI) for providing an indication of a fault on a monitored conductor, determining whether the FCI is near the end of its useful life (or entered into an end-of-life mode) and altering an operation of the FCI if the useful life of the FCI has reached a select threshold. The operation alteration may include an alteration of the display and/or deactivation of certain features and/or functions of the FCI. Thus, the useful life of the FCI will be increased. Further, utility personnel will be more likely to notice that the FCI is in end-of-life mode. The FCI may also include a battery discharge module and a thyristor for discharging the battery for disposal upon decommissioning of the FCI.

Abstract: In another embodiment, the invention provides a clamp meter configured to receive a removable and rechargeable battery pack. The clamp meter includes a main body having a first axis, a handle, a clamp, a trigger, and a display. The handle has a second axis and includes a first recess configured to receive the battery pack. The first recess includes at least first and second electrical terminals which are exposed when the battery pack is not inserted into the first recess. The second axis forms an oblique angle with the first axis, and the battery pack is inserted into the first recess along the second axis. The clamp is coupled to the main body, aligned with the first axis, and operable to measure an electrical characteristic of a conductor based on an induced current. The trigger is operable to selectively open and close the clamp, and the display configured to display an indication of the electrical characteristic.

Abstract: An electrical monitoring device for monitoring an electrically powered device is provided. The monitoring device includes a frame for placement onto a conductor of the electrically powered device. A sensor is present for detecting the amount of current passing through the conductor. Also, a display may be provided for indicating to the user parameters of the electrically powered device that are indicative of the current passing through the conductor.

Abstract: An intelligent electronic device (IED), e.g., an electrical power meter, having circuitry for reducing the burden placed on at least one current sensor of the device resulting in a highly accurate measurement by the at least one current sensor is provided. The circuitry of the present disclosure reduces the burden on the current sensor while providing amplification, e.g., gain control, to the input signal. The circuitry includes at least one current sensor outputting a signal to an operational amplifier (op amp) having a controlled variable feedback resistance. By employing an operational amplifier in the circuitry, the output of the current sensor will be at a near zero volts condition at all times thus reducing the burden on the current sensor.

Abstract: Electrical currents are detected and analyzed across structural members in a structural joint, such as a fastener of a vehicle. In some aspects, printed circuit boards etched with Rogowski coil circuits are inserted proximate the structural members in the structural joint. The Rogowski coil circuits may detect an electrical current as it flows through the structural joint. An integrator may integrate a transient current to generate an output signal, such as when the vehicle is subjected to an electrical charge. The output signal may be transmitted to an Integrated Vehicle Health Management (IVHM) system for analysis. In various aspects, the IVHM system may enable recording and reporting of various aspects of the current to enable maintenance, inspection, or real time/near real time health assessment of the vehicle.

Abstract: The accuracy and flexibility of a branch circuit monitor is improved by storing specifications, including error correction factors, for a plurality of current transformers in the monitor's memory and enabling current transformers with stored specifications to be selected for use with the monitor.

Abstract: The flexibility of a branch circuit monitor is improved by a signal conditioning unit that outputs a voltage in response to an input voltage and which is configurable to output the same range of output voltages in response to input voltages varying over different ranges.

Abstract: A device for diagnosing signal status of a driven object includes an insulation transformer, a signal generating device, a current measuring device, a feedback device, and a voltage measuring device. The insulation transformer has an intermediate tap at a midpoint of its primary winding. The signal generating device generates periodically vibrating voltage and includes a rectangular wave pulse voltage and alternating voltage. The current measuring device is connected to the intermediate tap of the primary winding to measure a current. The feedback device converts the current flowing from the intermediate tap of the primary side to a voltage corresponding to the drive voltage and feeds back the converted voltage to the input drive voltage signal. The voltage measuring device measures the voltage added with the feedback voltage. Diagnosis of the signal state is performed based on measurement results of the current measuring device and voltage measuring device.

Abstract: Devices, methods, and systems for non-invasive energy consumption monitoring are described herein. One or more device embodiments include a transformer configured to couple the device to a circuit conductor that is coupled to an additional device, a detection module configured to detect a change in a power signal over the circuit conductor, and a transmission module configured to transmit a unique signal associated with the additional device over the circuit conductor if the change in the power signal meets or exceeds a particular threshold.

Abstract: An inductor design having a detection winding which is magnetically coupled to the existing winding and its induction voltage is used to cancel that of the existing winding. Having the induction voltage cancelled, the voltage across the existing winding represents a resistive voltage drop of the existing winding current. The detection winding is furthermore built with a non-inductive portion having a significantly higher DC resistance in proportion to that of the existing winding. This resistance proportion is insensitive against temperature variations when both the existing and the detection windings are built with the same material and subjected to the same environment. A reference current is fed through the detection winding to produce a reference resistive voltage drop which is used to cancel the resistive voltage drop across the existing winding. When a precise cancellation occurs, the existing winding current is known to be in exact proportion to the reference current.

Abstract: Embodiments of the subject invention relate to a method and apparatus for determining information regarding a load in a planar wireless power transfer system by extracting system operating parameters from one or more test points in the transmitter circuit. As shown in FIG. 1, a specific embodiment showing three test points in the transmitter circuit from which operating parameters can be extracted. The transmitter circuit is designed to produce a magnetic field, by driving the transmitter coil, which inductively couples to a receiver coil such that power is provided to a receiver. By extracting operating parameters from the transmitter circuit, the receiver does not need to incorporate sophisticated signal processing and can be manufactured with low cost.

Abstract: A circuit for measuring current drawn by a self-powered electronic protection device. The circuit monitors current in a polyphase alternating current (AC) power source by measuring current in a rectified secondary winding of a current transformer coupled to a phase current of the power source. The measurement circuit includes a measurement burden connected between the cathode of the current transformer rectifier and a switch. Closing the switch references the voltage drop across the measurement burden to a reference potential. A controller closes the switch while receiving measurements of the voltage drop. Because the voltage drop is referenced to a reference potential, it can be analyzed in a controller to detect a fault condition without being conditioned with an inverting amplifier or a difference amplifier.

Abstract: A method and current sensor arrangement for measurement of a primary current in a primary conductor which is magnetically coupled to a secondary conductor via a ferromagnetic core, with a voltage of a specific amplitude being applied to the secondary conductor, such that a secondary current flows for remagnetization of the ferromagnetic core, and the secondary current is measured during the remagnetization of the core, in order to obtain a first measured value. The voltage polarity is then reversed such that a secondary current flows for renewed remagnetization of the ferromagnetic core, and the secondary current is measured during the remagnetization of the core, in order to obtain a second measured value. The primary current is calculated as a function of the first and of the second measured value, with the polarity reversal being carried out at least once at a time which occurs before that time at which the ferromagnetic core reaches its saturation magnetization.

Abstract: A current transformer is provided. The current transformer includes a magnetic core having a central opening, at least one pair of conductors extending through the central opening and positioned symmetrically with respect to a center point of the magnetic core, one or more coils disposed on the magnetic core along a magnetic neutral axis of the magnetic core and one or more coils disposed on the magnetic core along a reference axis, wherein the reference axis is substantially perpendicular to the magnetic neutral axis.

Abstract: An ammeter is provided with a plurality of individual wound coils interconnected in a generally U-shaped array to measure the magnitude of current in a conductor extending through a sensing region inside the U-shape. Additional pairs of position-sensing coils determine the position of the conductor relative to the sensing region and provide outputs to circuitry which permits the magnitude measurement to be displayed only if the conductor extends through the sensing region.

Abstract: A power monitoring system configurable to monitor electrical energy sensed by multiple sensors of one or more sensor arrays which may be organized in one of several array arrangements.

Abstract: A power distribution system sensor and/or control device is integrated with a wireless communication device in an encapsulating weather resistant housing. The device includes a power supply that is adapted to couple to a conductor of the power distribution network to provide rectified and conditioned power as necessary to operate the distribution and/or control device and the wireless transceiver. The wireless communication device may be a low power packet data radio transceiver operating in accordance with any suitable communication standard.

Abstract: A current sensor is provided for non-invasively measuring electrical current in an electrical conductor. The current sensor includes a housing having a Hall effect device and circuitry for transmitting a signal indicative of the current flowing through the electrical conductor. The current sensor includes a base having a surface for supporting an electrical conductor. A magnetic shielding member is coupled to the surface to shield the Hall effect device from stray or external magnetic fields. A compliant member is coupled to the magnetic shielding member opposite the surface. The compliant member compresses to allow the current sensor to accommodate a large variety of electrical conductor sizes. The compliant member further acts to bias the electrical conductor against the Hall effect device.

Abstract: A planar magnetic current sensor is described, incorporating a number of features designed to improve the efficiency and reliability of the basic sensor. The improvements comprise providing inner and outer conductive shields, an increased number of sensor elements for a given circuit board area, and distributing the resistance of the sensor circuitry. The conductive shields prevent high transient voltages and eddy currents that may damage the sensor itself. The depth of the inner and outer conductive shields is chosen to produce eddy currents sufficient to attenuate the magnetic fields associated with transient pulses of a frequency above the frequencies to be measured. An aperture is provided from the exterior of the conductive shields or sealing caps, if present, to an annular space, to allow an output signal to pass from the interior of the sensor to the exterior of the sensor for monitoring.

Abstract: A magnetic detecting device includes a first and a second magnetoresistive element, and a first and a second fixed resistor connected in series to the first and the second magnetoresistive element, respectively. The first and the second magnetoresistive element each include a pinned magnetic layer and a free magnetic layer with a nonmagnetic conductive layer in between. The first and the second magnetoresistive element have the same layer structure except that the nonmagnetic conductive layers have different thicknesses. The thicknesses of the nonmagnetic conductive layers are set so that a positive interlayer coupling magnetic field acts between the free magnetic layer and the pinned magnetic layer of the first magnetoresistive element and a negative interlayer coupling magnetic field acts between the free magnetic layer and the pinned magnetic layer of the second magnetoresistive element. The first and the second fixed resistor have the same layer structure.

Abstract: Electrical current transducer comprising a measuring circuit (6) and an inductor (4) for measuring a primary current IP flowing in a primary conductor (2), the inductor comprising a saturable magnetic core (10) made of a highly permeable magnetic material and a secondary coil (12) for carrying an alternating excitation i configured to alternatingly saturate the magnetic core, the coil being connected to the measuring circuit. The measuring circuit is configured to measure a mean value of the excitation current in the secondary coil and determine therefrom a value of the primary current for small current amplitudes, the measuring circuit being further configured for evaluating the frequency of the excitation current i and determining therefrom the value of the primary current for large currents.

Abstract: A current sensor is provided for non-invasively measuring electrical current in an electrical conductor. The current sensor includes a housing having a Hall effect device and circuitry for transmitting a signal indicative of the current flowing through the electrical conductor. The current sensor includes a base having a surface for supporting an electrical conductor. A magnetic shielding member is coupled to the surface to shield the Hall effect device from stray or external magnetic fields. A compliant member is coupled to the magnetic shielding member opposite the surface. The compliant member compresses to allow the current sensor to accommodate a large variety of electrical conductor sizes. The compliant member further acts to bias the electrical conductor against the Hall effect device.

Abstract: A method of detecting partial corona discharge in a targeted circuit of an electrical apparatus, comprises the steps of: wrapping a Rogowski coil around a leg of the targeted circuit to produce a Rogowski coil signal that represents electrical current rate of change in the leg of the targeted circuit; coupling the Rogowski coil signal to a three-dimensional display device that may represent the dimension of time, the dimension of amplitude as a function of a time, and the dimension of duration of amplitude as a function of time in successive periods of that have a preselected duration; monitoring the display device to detect deviations of the duration of amplitude as a function of time from a normal waveform in the leg of the targeted circuit; and correlating ones of the detected deviations of the duration of amplitude as a function of time from a normal waveform that exceed a preselected deviation level as indicative of partial corona discharge within the targeted circuit.

Abstract: A printed board, includes: a first shield portion, configured to reduce an influence of an electric field in combination with a casing accommodating the printed board, at least a part of the first shield portion being formed with a plurality of through holes; and a second shield portion, configured to reduce the influence of the electric field in combination with the casing, at least a part of the second shield portion being formed with a plurality of through holes, wherein the second shield portion is arranged alongside of the first shield portion.

Abstract: A method for measuring a current level of an alternating current uses a current transformer having a measurement winding and a test winding. The resistance of the test winding is measured, the temperature of the test winding and therefore of the measurement winding is determined therefrom, and a value for a current level measured on the measurement winding is corrected using that temperature.

Abstract: A Bulk Current Injection (BCI) transformer is provided herein with a magnetic core and a plurality of windings. The magnetic core is configured for encircling one or more electrical conductors under test. Each of the plurality of windings are wrapped, at least in part, around a longitudinal dimension of the magnetic core and spaced apart around an azimuthal dimension of the magnetic core. During injection tests, a power source may be coupled for supplying current to each of the windings at a respective “feed point.” Arranging multiple feed points around the magnetic core enables current flow through the windings to generate an azimuthally-uniform magnetic flux density in the magnetic core. The uniform magnetic flux density enables the BCI transformer to excite only common mode currents in the electrical conductors under test. BCI test methods, including injection tests and current sensing tests are also provided herein, along with a test setup for characterizing BCI transformers.

Abstract: A clamp jaw assembly for a clamp meter is provided. The clamp jaw assembly comprises a housing containing a clamp jaw core disposed within a shield. The housing, shield, and core of the clamp jaw assembly are configured to provide an extended creepage and clearance path from an exterior of the housing to a surface of the core.

Abstract: An apparatus for online partial discharge testing includes a split-core radio-frequency current transformer sensor, an actuation subassembly, and a biasing member. The current transformer sensor has a first portion, a second portion, and a sensor hinge operably engaged between the first portion and the second portion. The actuation subassembly includes an elongate first member secured to the first portion of the current transformer sensor, a second member secured to the second portion of the current transformer sensor and configured to be movable relative to the first member, and a third member engaged with the second member and configured to translate along a length of the first member. The biasing member is configured to pivotally bias the first portion and the second portion of the current transformer sensor toward each other relative to the sensor hinge, with the biasing member secured relative to the first member.

Abstract: An electrical power meter for monitoring electrical power supplied to a load comprises a meter case, a plurality of current transformers within the meter case for sensing the electrical current in a plurality of line conductors of a power distribution system, and a plurality of pairs of terminals on the meter case for connecting the meter to the line conductors. The terminals of each pair are located on opposite sides of one of the current transformers, and a current transformer bus bar connects the two terminals and extends through one of the current transformers. A plurality of guides adjacent selected pairs of the terminals position lugs connecting line conductors to the selected pairs of terminals.

Abstract: Apparatus and methods are provided for the measurement of a power factor at points of interest, such as circuit breakers, machines, and the like. Accordingly, means are provided for measurement of a power factor for each electrical sub-network that is controlled by a circuit breaker. Each apparatus is enabled to communicate its respective data, in an environment of a plurality of such apparatuses, to a management unit which is enabled to provide finer granularity power factor profiles.

Abstract: A circuit-breaker is disclosed, in particular a low-voltage circuit breaker. In at least one embodiment, the circuit breaker includes a Rogowski current transformer for measuring a current in a conductor of the circuit-breaker, the Rogowski current transformer including at least three coil sections electrically connected in series and arranged to form a closed polygon, two coil sections in each case in the corner region of the closed polygon forming a joint region not taken in by the coil sections. In order to provide, for a circuit-breaker, an inexpensive current transformer with a high measuring accuracy which is made up of coil sections, in at least one embodiment at least one of the joint regions formed has a ferromagnetic material for shielding the joint region against magnetic interference fields.

Abstract: The invention relates to methods and devices for accurately monitoring the electrical current in electrolytic cells used to produce metals, including but not limited to aluminum, or other chemical substances. A plurality of sensors are placed at some distance from the conductor, with at least two sensors at a known distance from each other. Measurements from the plurality of sensors are used to calculate the electrical current.

Abstract: This invention provides a clamp meter with safe trigger mechanism which allows an operator to take electrical measurements of the conductors safely, particularly in case of the electrical conductor elements situated in congested or awkward locations and positions. In the preferred embodiment of the present invention, the trigger is placed at the underside of said clamp meter so as to allow convenient access to it for the fingers of a hand while the clamp meter is held in the hand. The trigger mechanism of the invention may be operated with single or multiple fingers. The invention also allows the hand to maintain its ‘clinched-fist’ position throughout the measurement process, thereby eliminating the need to open the hand any time during the process. The invention thus makes the electrical parameter measurement operation using clamp meters safer than for the conventional meters.

Abstract: An apparatus for online partial discharge testing includes a split-core radio-frequency current transformer sensor, an actuation subassembly, and a biasing member. The current transformer sensor has a first portion, a second portion, and a sensor hinge operably engaged between the first portion and the second portion. The actuation subassembly includes an elongate first member secured to the first portion of the current transformer sensor, a second member secured to the second portion of the current transformer sensor and configured to be movable relative to the first member, and a third member engaged with the second member and configured to be movable relative to the first member. The biasing member is configured to pivotally bias the first portion and the second portion of the current transformer sensor toward each other relative to the sensor hinge, with the biasing member secured relative to the first member.

Abstract: An optical voltage transformer is connected with an external electric device and includes a primary electrode to which a measured voltage is applied by the external electric device, a first secondary electrode provided oppositely to the primary electrode, an insulation layer provided between the primary and first secondary electrodes and constituting an insulation cylinder integrally formed with the primary and first secondary electrodes, a ground layer provided on an outer circumference of the insulation cylinder and around the first secondary electrode for securing a capacitance by interposing the insulation layer between the ground layer and the first secondary electrode, and an electro-optic element for measuring a voltage between the first secondary electrode and the ground layer.

Abstract: The sensor comprises a cable (5) looped around an element to be monitored, and includes a winding (10) on the Rogowski principle. It is original in that it is open at its ends (6, 7), that is to say the winding (10) is flush with the end faces (25) of the cable (5), and perfect continuity of the winding and of measurement over a circumference is established by abutting the two ends together. This cable may have a temperature sensor and a memory in which the measurement characteristics of the sensor are held. The sensor is reliable and accurate, and it can be left permanently in an electrical apparatus, or replaced, with no difficulty.

Abstract: Provided is a sensor circuit that is small in circuit scale, but is capable of temperature compensation. A reference voltage circuit (BL1) which compensates a temperature includes only a voltage divider circuit, and hence the sensor circuit is small in circuit scale. The sensor circuit is also capable of temperature compensation because temperature changes of reference voltages (VTH11 and VTH12) and reference voltages (VTH21 and VTH22) match a temperature change of an output signal (OUTA) of an amplifier circuit (AMP1) which is caused by a temperature change of an output signal of a Hall element (HAL1).

Abstract: A device for measuring currents induced in a CAN bus harness. In some embodiments, the device includes a first termination node, a second termination node, a current separator, a detection circuit, and a power source circuit. The current separator circuit has an RF transformer connected to the first termination node and separates a common mode RF current and a differential mode RF current of an RF current signal. The detection circuit is connected to the current separator circuit and receives at least one of the common mode RF current and the differential mode RF current from the separator circuit. The detection circuit also converts the common mode RF current and differential mode RF current to an non-RF output signal. The power source circuit provides power to the detection circuit.

Abstract: A highly accurate current sensing transformer, such as an external neutral current transformer (ENCT), accommodates a wide range of loads. The ENCT includes a housing, first and second terminals each having an end portion extending from and external to the housing, a conductor for carrying a current to be measured, and a current sensor having an aperture for receiving the conductor and having a central axis. The conductor joins the first and second terminals to form a current path that passes through the aperture. Increased accuracy is achieved by arranging the conductor such that a portion thereof passing through the aperture forms a substantial angle relative to the central axis, such that the entry angle of the current path via the conductor through the aperture of the current sensor of the ENCT matches an entry angle of a conductor through an aperture of a current sensor in the electronic trip unit to which the ENCT is attached.

Abstract: A system comprising a magnetic actuator, a current transformer and operational electronics in a dual-coil circuit breaker. The system includes an inline, but non concentric, implementation of the primary and secondary coils to maintain a narrow width suitable for retrofitting in standard industrial rack mounted enclosures. The system further comprises a split core design that is integrated into an upper and lower plate which slide together and are retained by a secondary coil bobbin. Typically, the two parts of the split core can be manufactured into net shapes by utilizing a powder metal or metal injection molding process. Moreover, the split core design disclosed herein can reduce costs and time associated with manufacturing and assembly of the current transformer.

Abstract: The invention relates to a method and a device for determining a direct current (i(t)) flowing in a conductor (7) and having an amplitude greater than 500 A, which direct current (i(t)) is composed of a number of time-dependent partial currents (ii(t)) flowing in individual conductors (8) with switching elements. To create a drift-free measured value, it is provided that at least one Rogowski coil (10) is arranged around at least one of the individual conductors (8) for the induction of a partial voltage (ui(t)) through the at least one partial current (ii(t)), wherein the individual conductor (8) is formed by a path of a rectifier (6) on a secondary side of a transformer (5) with central tapping, the at least one integrator (11) is designed for integration of the at least one partial voltage (ui(t)), and the at least one integrator (11) is connected to an evaluation unit (12) for determining the direct current (i(t)).