Abstract: A transformer circuit is disclosed that minimizes the temperature dependence of an output voltage. A first embodiment of the present invention includes a primary winding coupled to receive a voltage to be sensed and a center-tapped secondary winding coupled at a center point to a first voltage output terminal. The center-tapped secondary winding includes a first secondary winding and a second secondary winding, the secondary windings being coupled through a bridge circuit to a second voltage output terminal. Details of this and other embodiments are disclosed.

Abstract: A non-invasive powerline communications system includes: means for generating communication signals at a first location for transmission on a powerline; means for reactively coupling the communication signals to the powerline; and means for receiving said communication signals at a second location.

Abstract: A current sensor for sensing current in a primary source, including a primary conductor forming at least one winding on a first portion of a toroid formed from a magnetic material. A secondary source of electrical current from a signal forms a plurality of winding on a second portion of the toroid. An output reader measures the instantaneous loading of the signal passing through the plurality of windings as a function of the primary source current. The preferred toroid is formed from an amorphous core magnetic material having an hysteresis saturation point is much larger than the coercivity of the material and said primary source of electrical current is AC or DC current. The device includes an amplifier for receiving the signal and place an AC voltage or current on the plurality of windings, and further includes a resistor form measuring the resulting voltage or current instantaneous loading.

Abstract: A sensor apparatus for a power bus including a current and a temperature includes a housing and one or more sensors. Each of the sensors is adapted to sense one of the current or the temperature of the power bus. A radio transceiver circuit is adapted to transmit a first wireless signal and to receive a second wireless signal. A processor is adapted to input the sensed current and the sensed temperature from the sensors and to output corresponding signals to the radio transceiver circuit in order to transmit the first wireless signal. A power supply is adapted to employ voltage produced by magnetically coupling the power bus to one or more coils, in order to power the sensors, the radio transceiver circuit and the processor from flux arising from current flowing in the power bus.

Abstract: An apparatus and a method for testing semiconductor devices, such as individual integrated circuits in semiconductor chips, by directing a current in each circuit through a respective selected predetermined path to establish, in each circuit, a respective focused magnetic field and converting each such magnetic field into a respective voltage which, when fed to respective amplifier gated with a respective selected frequency, will modulate each such respective voltage. Each such respective voltage is then used to create a respective pulsating magnetic field that when detected by a respective remote magnetic sensor will provide a series of respective signals representative of the current in the respective circuit from which the pulsating magnetic field was derived.

Abstract: An electric current detection apparatus has a single magnetic sensor for detecting a first current which flows from a battery and also a second current which flows into or from the battery during different occasions from the first current and is substantially smaller than the first current. The magnetic sensor has a magnetic core surrounding first and second conductors, with the second conductor carrying the second current and with the first conductor being shunted by a third conductor such as to conduct a predetermined proportion of the first current.

Abstract: A fault indicator for indicating the occurrence of a fault in an electrical conductor is automatically configured for an overhead application or for an underground application. The fault indicator has a housing, a battery, a display for indicating the occurrence of a fault, a current sensor for sensing the load current in a monitored conductor, and electromagnetic field sensor to sense the electromagnetic field about the conductor, and a microcontroller for determining whether a fault condition occurred, for determining the magnitude of the electromagnetic field, and for configuring the fault indicator in the overhead configuration if the electromagnetic field is above a predetermined magnitude or configuring the fault indicator for the underground mode if the field is below the predetermined magnitude.

Abstract: An electric current sensor includes: a core having a ring shape and including a plurality of core pieces, which are laminated and integrated to provide the core; a magnetic gap disposed on a predetermined part of the core; a Hall element disposed in the magnetic gap; a body for accommodating the core and the Hall element; and a seal member for sealing the core and the Hall element into the body. Each core piece has a thin plate shape, and the core includes deformation preventing means for preventing a deformation of the magnetic gap.

Abstract: The Rogowski type current measuring device comprises at least three coils electrically connected in series and forming a closed polygonal outline designed to surround a conductor to perform current measurement. The local inductance of at least one of the ends of said coils is greater than the local inductance towards the central part of said coils.

Abstract: An improved flow-through conductivity sensor is provided. The sensor includes a current return path that has a current return conductor. At least one toroid of the sensor is removed from the flow path and configured to interact with the current return conductor to provide an indication of conductivity. Additional aspects of the invention include disposing a pair of toroids about the current return conductor; disposing a toroid about the current return conductor and configuring the toroid as a transformer.

Abstract: A voltage acquisition circuit for sensing input voltage signals in each phase of an electrical service includes a non-active current transformer configuration that is operable over a wide input voltage range. The current transformer configuration includes primary and secondary windings, an input resistor and a burden resistor across which an output voltage is defined. The input resistor may be relatively large, such as on the order of about one M? and the transformer core may have a nanocrystalline core characterized by predictable magnetic properties versus varied transformer flux levels. This operational predictability facilitates phase compensation via digital filtering or otherwise for any phase shift induced between input and output voltages of the current transformer.

Abstract: A fault indicator for indicating the occurrence of a fault in an electrical conductor has a housing, a high capacity battery, a plurality of emitting diodes (LEDs) visible from the exterior of the fault indicator upon the occurrence of a fault, and electronic circuitry for sensing a fault, for actuating the LEDs to indicate a fault and to provide a timed reset of the LEDs to a non-fault indicating condition a predetermined time after the fault has occurred. The electronic circuitry, including a microprocessor that is normally in a sleep mode, conserves energy by drawing insubstantial current from a high capacity battery during non-fault conditions. Preferably, the microprocessor controls activation of the fault indicating LEDs with pulse width modulated (PWM) signals during defined time intervals for improved visibility. Visibility is further improved where the PWM signals for the indicator LEDs are interleaved in time to provide a highly distinctive flicker effect.

Abstract: A method for evaluating the accuracy of a current transformer is presented. The current transformer has a primary winding and a secondary winding. A current is not circulated through the primary winding. A load is disconnected from the current transformer. A load impedance is measured of an internal instrumentation associated with the current transformer. The resistance in the secondary winding of the current transformer is determined. The load impedance is compared to a standard burden. A standard burden value is selected. The secondary voltage for a rated current is determined. The injection voltage is adjusted to the value of the secondary voltage. The exciting current and power are measured. The ratio error or the phase angle are then calculated by using the exciting current and power.

Abstract: A measuring circuit arrangement (1) for an electricity meter for direct connection is respectively connected, to an input (3) for voltage measurement and an input (4) for current measurement of a measuring chip (2) for each phase of a three phase supply. Upstream of the input (3) for voltage measurement is a voltage divider (R1,R2) provided in order to match the voltage level, and upstream of the input (4) for current measurement is a voltage transformer (5) with measuring shunt (RSH) installed according to the invention. The voltage transformer (5) is so arranged that its ohmic resistance towards the measuring shunt (RSH) on the one hand sufficiently limits standard direct-current impingement of the voltage transformer (5) and on the other hand this ohmic resistance is also small enough so that, together with the inductance of the current transformer (5), it displays no more than standard angle error.

Abstract: Disclosed are systems and methods for indicating events at various locations in a power distribution system.

Abstract: Various circuit configurations for use in switch assembly used in a surgical hand piece system are provided. The circuit configuration provide a number of functions such as permitting the presence and direction of conductivity to be detected. The circuit configurations also provide a means for detecting and measuring the degree of influence of debris which is located between the conductive members of the handpiece. In addition, the circuit configurations also provide a means for identifying the type of switch end cap which is attached to the handpiece. The handpiece body and the switch mechanism are electrically connected to one another in such a manner that permits the switch end cap to be freely rotated about the handpiece body and reduces the number of conductive members needed to communicate the status of each switch.

Abstract: The present invention relates to an apparatus for measuring the capacitance and the dissipation factor in a transformer bushing and extracting gas dissolved in the insulating fluid of said bushing. The apparatus comprises a porous cylindrical member associated with a tap connector and covered by a thin layer of a gas permeable but liquid impermeable membrane. The porous member allows passive diffusion of the permeated gas extracted from the insulating fluid of a transformer bushing to a gas storage chamber for further analysis, thereby helping to prevent high costs related to damage or destruction of the bushing.

Abstract: A current sensor assembly includes a sensor coil, an electrostatic shield coil, a core, a housing, and a magnetic shield. The sensing coil, electrostatic shield coil, core, housing, and magnetic shield can be of toroidal symmetry and arranged coaxially about a pair of primary current conductors. The conductors can be either asymmetric or symmetric with respect to the geometric center of the remaining sensor assembly. The core and a secondary winding make up a current sensor. The core is cylindrically shaped and fabricated of non-magnetic material. The secondary winding is wound over the cylindrical core to form a toroidally shaped winding. When assembled into the current sensor assembly, the core and windings are disposed around two single turn primary windings through which AC currents to be measured flow. Alternatively, the conductor can be flat and the sensor can be a solid state sensor that includes an electrostatic shield.

Abstract: The invention relates to a method for generating an error signal which characterizes a fault current in an electrical conductor provided with two conductor ends and having charge measuring devices which are connected to each other by data lines. At least one device is attached to each end of the conductor. In the invention, charge measuring values are determined using charge measuring devices. The measured charge values take into account the direction of the charge flow and a total measured charge value is formed by addition. The error signal is generated when the total measured charge value exceeds a certain threshold value. In order to be able to detect errors in a more sensitive manner than had previously been possible, the threshold value is formed by taking into account the individual measuring tolerance of the individual charge measuring devices.

Abstract: A fault indicator for indicating the occurrence of a fault in an electrical conductor has a plurality of trip settings, such as in the range of 50 A to 1200 A, that is automatically calibrated. The fault indicator includes a housing, a battery, an illuminated display, such as LEDs, a current sensor for sensing the load current in the conductor and a microcontroller that receives a current signal from the current sensor to determine the load current. In the calibration mode, a known load current is passed through the conductor, the microcontroller selects the trip level that is related to the load current, determines the load current from the current signal, and sequentially calibrates each of the plurality of trip levels for the respective known load currents. The calibration information is stored in memory. The illuminated display provides a distinctive pattern to indicate that each trip setting has been calibrated.

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: An apparatus that controls the supply of electrical power including one or more monitors adapted to sense a state of current flow supplied to a device, one or more controlled sockets, a power input; and a logic circuit. The logic circuit controls the supply of electrical power to at least one of the controlled sockets responsive to the sensed state of current flow supply to the sensed device.

Abstract: A device, an ammeter and a motor vehicle, having a first section and a second section of a conductor for the purpose of measuring the electrical amperage in the conductor are described; a first sensor means and a second sensor means being provided; the current flowing in the first section and in the second section generating a useful magnetic field; the first sensor means being provided to measure the useful magnetic field; the second sensor means being provided in a location where the useful magnetic field disappears; the second sensor means being provided to measure a magnetic interference field; and the measurement of the useful magnetic field being correctable by the measurement of the magnetic interference field.

Abstract: The accuracy of certain sensors is greatly improved by improving their signal to noise ratio (SNR) in the presence of an interfering noise. Sensors were discovered which have a SNR which substantially changes when an operating parameter is selectively modulated to different magnitudes. Some noise can be practically eliminated. In the simplest form, the sensor is operated where it is both stable and close to its best SNR This is usually faster and less costly, but the noise is never completely eliminated. Often, the method involves operating the sensor in first one state and then another wherein the operating parameter has conditions where the sensor is stable, reproducible, and reliable, and wherein the SNRs are substantially different. The output of a state is combined with the output of another state in such a way that the noise cancels but a signal remains. Often the output in a state having greater noise is attenuated until it matches the noise content of another state having less noise.

Abstract: A power monitoring system for electrical panels providing multi-phase power, with multiple current sensors. The disclosed power monitoring system preferably includes a support, at least four sensors defining an opening through which a wire may be extended, with the sensors being supported by the supports in a fixed spatial relationship.

Abstract: A partial discharge detection test link and system is disclosed to detect partial discharge of a power cable accessory. The power cable accessory includes a first accessory component and a second accessory component connected to each other. The partial discharge detection test link is a permanent or temporary substitute for a conventional service link, connects directly across the power cable accessory and includes a conductor member and a partial discharge sensor. The conductor member has an electrically conductive element and an insulation surrounding and extending along the electrically conductive element. The electrically conductive element is electrically connected directly between the first and second accessory components. The partial discharge sensor is disposed about the conductor member and has the electrically conductive element as a primary winding and a secondary winding with the insulation positioned between the primary and secondary windings.

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 method and apparatus for transformer bandwidth enhancement is disclosed. In one embodiment, a transformer is provided for use in a high frequency communication environment. In one configuration, the transformer is configured with one or more compensation networks to improve high frequency operation and to reduce insertion loss at all frequencies. The compensation networks may be designed, in combination with a transformer, to create an equivalent all-pass symmetric lattice network having a frequency response in the desired range. In one embodiment, the compensation networks comprise a capacitance creating device which, when cross-connected to the transformer, increases transformer bandwidth.

Abstract: A fault indicator for indicating the occurrence of a fault in an electrical conductor has a housing, a high capacity battery, a display for indicating the occurrence of a fault, a current sensor for sensing the load current in a monitored conductor a microcontroller for determining the load current, for selecting one of a plurality of trip settings, such as in several steps between 50 A and 1200 A, based upon the determined load current and for determining that a fault condition occurred when the load current exceeds the trip setting. The selected trip setting is stored in memory. The load current is periodically sampled and the trip setting is changed if the load current falls in a different range. The display may include permanent and temporary fault indicating LEDs and additional internal LEDs that cause the housing to glow or flash at nighttime, or a target style display may be used. Upon the load current exceeding the trip setting, the microcontroller begins flashing the permanent fault LEDs.

Abstract: A current sensor according to the present invention is provided with a U-shaped conductor through which current under measurement flows, a magnetic sensor disposed between two straight portions parallel to each other both of which form the U-shaped conductor, a magnetic material of surrounding shape which surrounds the two straight portions and the magnetic sensor and includes a convex opposed to the magnetic sensor and a supporting member for supporting the conductor, the magnetic sensor and the magnetic material so as to position ends of the conductor and terminals of the magnetic sensor at the same side with respect to the magnetic material.

Abstract: The invention relates to a method for generating an error signal which characterizes a fault current in an electrical conductor provided with two conductor ends and having charge measuring devices which are connected to each other by data lines. At least one device is attached to each end of the conductor. In the inventive method, charge measuring values are determined using charge measuring devices. The measured charge values take into account the direction of the charge flow a total measured charge value is formed by addition. The error signal is generated when the total measured charge value exceeds a certain threshold value. According to the invention, the measured charge values are determined synchronously and determined repeatedly at regular intervals in such a way that the time interval between each sequential determination is smaller than the predefined measuring period.

Abstract: A panelboard having an enclosure includes at least one busbar having a plurality of electrical distribution connection points, and a current transformer module having a current transformer integral with and in signal communication with each of the busbars. A signal path is associated with and in signal communication with each current transformer for communicating a signal therefrom. In application, a load current passing through each of the busbars within the panelboard results in a signal, representative of the associated load current, at the associated current transformer and signal path.

Abstract: An electrical energy meter comprises an electrically insulating housing (10) for securing relative to least two mains cables (22,24) each having a conductive core surrounded by a sheath of insulating material. The housing includes respective electrical contacts for piercing the insulating sheath of each cable, a current probe for measuring current flowing in at least one of the cables, and circuit means for calculating and displaying electrical energy as a function of the voltage across the contacts and the output of the current probe. An improved current probe is employed comprising a series of Rogowski coils equally spaced around the circumference of a circle, with the gap between two adjacent coils permitting the current-carrying conductor to be introduced into the loop. An alternative current probe employs two such concentric loops of coils, enabling compensation for the effects of external current source pickup.

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: A monolithic transformer compensated circuit with enhanced quality factor without significantly increasing noise levels is presented in this disclosure. The technique uses a monolithic transformer and a current source driving current into the transformer secondary winding to achieve loss compensation in the transformer primary. An ac current which is proportional to, and in phase with the voltage applied to the primary winding can be used to achieve theoretically perfect loss compensation at a given frequency in the RF (GHz) frequency range. Examples of circuit applications that are particularly suited to the technique include Voltage Controlled Oscillators (VCO's), Low Noise Amplifiers (LNA's) and Filters. The technique has the added advantage of reducing power consumption in some applications.

Abstract: A current probe transformer temperature monitoring method determines an initial transformer temperature of the current probe as a function of the winding resistance of the transformer. A relative temperature of the Hall Effect device is also determined as a function of resistance change of the Hall Effect device. The initial transformer temperature and the relative Hall Effect device temperature are combined to produce a continuous transformer temperature indicative of the temperature of the transformer. The current signal to the multi-turn winding is removed when the continuous transformer temperature exceeds a threshold temperature value and a visual indication may be provided.

Abstract: Various circuit configurations for use in switch assembly used in a surgical hand piece system are provided. The circuit configuration provide a number of functions such as permitting the presence and direction of conductivity to be detected. The circuit configurations also provide a way to detect and measure the degree of influence of debris which is located between the conductive members of the handpiece. In addition, the circuit configurations also provide a way to identify the type of switch end cap which is attached to the handpiece. The handpiece body and the switch mechanism are electrically connected to one another in such a manner that permits the switch end cap to be freely rotated about the handpiece body and reduces the number of conductive members needed to communicate the status of each switch.

Abstract: An electrical sensing device that includes a support and sensors supported by the support in a fixed spatial relationship.

Abstract: The invention relates to a transformer comprising a closed probe core (2) consisting of a soft magnetic material, a probe coil (3), at least part of which is wound around the probe core (2), a closed compensation core (1) consisting of soft magnetic material, and a compensation coil (4), at least part of which is wound around the probe core (2) and the compensation core (4). The probe core (2) and the compensation core (4) are arranged in relation to one another in such a way that a conductor (5), which carries a measuring current, can be guided through the probe core (2) and the compensation core (1).

Abstract: A residual current detection device comprising a plurality of resistive shunts for connection in respective ones of a plurality of lines though which current can flow to and from a load, and detector means sensitive to the voltage developed across each of the shunts to detect any imbalance between the currents flowing though the shunts.

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: 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 method for determining position of a device includes generating at least two, time-varying, magnetic fields using inductive elements, wherein the fields have differing phases. The method further includes detecting a signal modulated on top of the fields, wherein the signal is generated from the device, and determining a position of the device based on a phase difference of the signal from the device and a reference signal.

Abstract: The circuit arrangement for generating square pulses according to a magnetic field strength has an edge-triggered flip-flop a comparator connected to the flip-flop; a bridge with four bridge segments, each including an electronically controlled switch, and with a transverse branch including an energy-storing element consisting of an inductive resistor acting as a magnetic field probe; and a switching threshold resistor connected with the energy-storing element and with a signal input of the comparator. The switches are each connected in pairs in crossover fashion by the flip-flop, so that current flow in the transverse branch is reversible. An improved compensation current sensor, which is less sensitive to component tolerances, includes the circuit arrangement for generating square pulses in a controller.

Abstract: A method and apparatus for configuring a current carrying and current sensing configuration using a rigid magnetically permeable guide core extending between facing first and second guide ends, the first and second ends of the core defining a sensing gap having a sensing dimension therebetween, an internal surface of the core forming a core space, the method including sliding a segment of a conductor through the sensing gap and into the core space such that the conductor extends through the core space, attaching a flux sensor to a clip member and mounting the clip member within the sensing space such that the sensor is within the sensing space.

Abstract: A current transformer to be installed around a current-carrying conductor. The transformer has a split core with two parts, which can be opened to allow the transformer to be installed around or removed from the current-carrying conductor. A winding wound on the core is operatively connected to a switch so that the winding can be shorted prior to opening the split core when the transformer is removed from the current-carrying conductor in order to reduce the magnetic force holding the split core parts together. The winding is shorted by the switch prior to closing the split core parts when the transformer is installed around the conductor in order to minimize the damage to the core due to the induced magnetic force thereon. A mechanical tool is used to open or close the split-core parts. The switch can be linked to the tool for shorting and opening the winding.

Abstract: A magnetic field sensor is provided with a device for producing an output signal that is a function of a magnetic field to be sensed. A calibration coil is arranged so as to change the magnetic field when energized, and a switch for selectively energizing the calibration coil is included. Calibration of the magnetic field sensor is accomplished by operating the switch to cause a known current to flow through the calibration coil, measuring the resultant change in the magnetic field, and calculating a sensitivity for the magnetic field sensor from the measured change in the magnetic field and the known current.

Abstract: A fault indicator for indicating the occurrence of a fault in an electrical conductor has a housing, a high capacity battery, at least one light emitting diode (LED) visible from the exterior of the fault indicator upon the occurrence of a fault, and electronic circuitry for sensing a fault, for actuating the LEDs to indicate a fault and to provide a timed reset of the LEDs to a non-fault indicating condition a predetermined time after the fault has occurred. The electronic circuitry, including a microprocessor that is normally in a sleep mode, conserves energy by drawing insubstantial current from a high capacity battery during non-fault conditions. During fault conditions, a light sensor senses the ambient lighting conditions and the microprocessor reduces current supplied to the LEDs under reduced lighting levels, such as night, further conserving battery life. The LEDs may also be operated at an intermediate illumination level, such as at dusk or dawn.

Abstract: A current sensor for measuring the load in a fiscal power meter has conductive paths connected between an inlet and an outlet for guiding the load currents through the sensor, and operates by sensing local magnetic fields generated around the conductive paths by the current flowing there through, thereby providing a current measure indicative of the magnitude of a given load. The sensor is distinguished by plural current coil elements arranged in a substantially common plane so as to be substantially insensitive to remotely generated magnetic fields but responsive to local magnetic fields for generating the current measure. The coil elements are disposed in zones having more than two effective centres and exhibiting mutually opposing responses to the remote field.

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.