Abstract: An apparatus for sensing and measuring the HV surge arrester current includes two toroidal current transformers arranged coaxially with respect to the earth wire of the surge arrester, elements for sensing the current signals emitted by the transformers and for converting the current signals in digital signals, and elements for transmitting the digital signals to an information network and analog state signals by relay activation. The two toroidal current instrument transformers are associated, respectively, one to elements for sensing the normal leakage current, and the other to elements for sensing the impulsive current, the latter comprising a circuit (TRIGGER) discriminating between “switching” and “lightning” signals, in which the basis for discrimination is a signal duration threshold, of about 35 ?s.

Abstract: A battery powered water leak detector and audible alarm are held on a credit card sized plastic board that has sufficient unobstructed area for visible messages, such as advertising, to be printed of otherwise affixed thereon.

Abstract: A system for detecting loss of an electrical phase in a compressor system includes a compressor system component having a plurality of phase carrying legs; a sensor for measuring current communicated with one leg of the plurality of phase carrying legs; and a processor unit adapted to receive a signal from the sensor and determine whether loss of phase has occurred in any of the plurality of phase carrying legs.

Abstract: The invention relates to a method and arrangement for generating a trigger signal according to the current differential protection principle when a fault occurs on a section of an electrical power supply system, in which differential current values and stabilization current values are detected and monitored with regard to exceeding limit values. A trigger signal is generated if positive results of the instances of monitoring are present. The differential current values and the stabilization current values are calculated with instantaneous values of the detected power supply currents as instantaneous values. A first measurement quantity and a second measurement quantity are formed, and a check is made to determine whether the two measurement quantities exceed a predetermined limit value of the differential quotient of the differential current with respect to time. If the instances of evaluation and the instances of monitoring produce positive results, the trigger signal is generated.

Abstract: The invention relates to a method, a computer programme and a device (2) for determining contact wear in an electrical switchgear (3) in an electric switchgear assembly (1) as well as to a switchgear assembly (1) with such a device (2). According to invention, for determining a contact wear status variable (Cwsum) a current measuring signal (Imess) is monitored for deviations (&Dgr;) from an expected faulty switch-off current (If) and, in case of deviations, the status variable (Cwsum) is not immediately calculated from current measuring signal (Imess), but indirectly using a characteristic current value (Ichar). Embodiments, among other things, relate to: deviations by saturation of the current transformer (30) and maximal current measuring signal (Imax) as characteristic current value (Ichar); status variable (Cwsum) as a measure for arcing power during switching-off and, in particular, equal to a potential function (f(Imess)) of the switch-off current (Imess).

Abstract: A trip unit is provided with a microcontroller and non-volatile memory, such as EEPROM (Electrically Erasable Programmable Read Only Memory) or Flash memory, for storing trip setting values, including initializing parameters, boot code, and operational parameters being capable of analog or digital programming depending on a switching instruction. This configuration enables one to change the trip unit's trip setting values after it is manufactured either remotely or locally. The present invention provides thus increased functionality to trip units by enabling upgrades and servicing of the trip unit by downloading replacement trip setting values to it and having multiple operational parameters (trip setting values) available.

Abstract: The instantaneous overcurrent element, used in a microprocessor-based protective relay for a power system, includes a finite impulse response filter which generally is a cosine filter and is responsive to the current waveform from the current transformer for fault determination unless the distortion in the current reaches a preselected threshold, at which point a peak detector circuit is used to provide the current magnitude values for fault determination.

Abstract: A current measuring device for a multi-pole voltage circuit breaker includes a support body with a through opening for a current conductor for each of the poles and a receiving chamber, surrounding the through opening for secondary components of current sensors and/or current transformers. The support body is essentially plate-like and rectangular and forms part of the rear wall of the circuit breaker. Should Rogowski coils be used as secondary components of a transformer, then adjustable voltage dividers are also mounted on the support body for interdependent adjustment. The multi-pole current measuring device simplifies the production of circuit breakers as approved components.

Abstract: A power supply feedthrough protection circuit which solves the problem of voltage feedthrough from a bus cable charging a chip power-supply beyond acceptable transistor limits. The circuit continuously senses the chip power-supply, compares the supply to an acceptable threshold, and provides a low-impedance current path as soon as the power-supply exceeds the threshold. The circuit allows a driver to draw current from the cable, in a controlled manner, and provides that the power supply is therefore never allowed to exceed the maximum allowable limit for transistors.

Abstract: A protection device includes a measurement device that is a current transformer which is based on a printed circuit, and an evaluation device that is a unit for early short-circuit identification. The current transformer, which is based on a as printed circuit board, is preferably a multiwinding transformer. The unit for early short-circuit identification operates on the basis of a so-called locus curve method, which uses instantaneous values of the current and current rate of change to identify a short circuit.

Abstract: A three-phase motor protector uses two toroids to monitor all three phases of a three-phase motor. Current and phase loss are monitored directly in phases A and B while the phase C current level is determined by analysis of the phase A and B relationship. Current is induced into the phase A and B toroids from the motor supply lines with the resulting wave fed to an input of high-gain inverting amplifiers to provide A and B square waves which are inputted to separate channels of a microprocessor (U3). The square waves are processed by an AND gate providing an output square wave with a 16.66 percent duty cycle for normal operation. Upon loss of phase C the ANDed result is a digital low since the individual waves of phases A and B become an inverse of one another. In order to prevent nuisance tripping an AND output of less than 2 percent duty cycle is treated as a phase loss.

Abstract: A current sensing system including a carrier strip, the carrier strip disposed so as to be associated with a current carrying conductor, wherein when an electrical current flows through the conductor, the electrical current flowing through the conductor creates a magnetic field having a magnetic flux, wherein the magnetic flux is responsive to the electrical current flow, a Hall effect sensor disposed relative to the carrier strip such that the Hall effect sensor is communicated with the magnetic field, wherein the Hall effect sensor generates an electrical signal responsive to the magnetic flux and a metering device in communication with the Hall effect sensor, wherein the metering device processes the electrical signal so as to create a processed signal responsive to the electrical current flow.

Abstract: A residual current device (1), having a residual current tripping circuit (4) which is independent of the mains voltage and contains a core balance transformer (2), and having overload protection (18) arranged in an overload tripping circuit (10) which is supplied with the mains current, wherein the residual current tripping circuit (4) and the overload tripping circuit (10) contain a common tripping relay (7) for operating a switching mechanism (8) which switches a conductor network (LN).

Abstract: Two detection systems are provided for a protective device, in particular an FI protective device, having a core balance transformer whose secondary winding is followed by a tripping relay for operating a switching mechanism, which switches a conductor network. In this case, a first detection system carries out the tripping function for fault currents at a fault current frequency below a changeover frequency. The second detection system carries out the tripping function for fault currents above the changeover frequency. The changeover frequency is in this case preferably not less than 1 kHz.

Abstract: An overcurrent/leakage protection circuit installed in an electric socket or the like for over current/electric leakage protection, which includes a relay, a SCR (silicon controlled rectifier) which controls the relay, a trigger circuit which triggers the SCR, a constant current detector, and a micro current detection amplifier, wherein the relay has a common contact connected to a first power line, a normal close contact for power output of the first power line, and a normal open contact bridged to a second power line through an alarm lamp; the trigger circuit is driven to trigger the SCR upon detection of an overcurrent or short-circuit detected by the constant current detector or an electric leakage by the micro current detection amplifier, causing the normal close contact to be opened to cut off power supply from the load.

Abstract: A trip unit input circuit configured to generate a signal proportional to current in respective phase lines of a power line and to provide operational power from a corresponding primary current transformer, the circuit comprising: a current sensor circuit configured to provide an output signal indicative of current flow through a respective phase line; a secondary current transformer in operable communication with the corresponding primary current transformer; and a power supply circuit coupled to an output winding of the secondary transformer, the power supply circuit being isolated from the current sensor circuit by the secondary current transformer.

Abstract: An algorithmic system for an electronic trip unit is provided whereby reliable instantaneous protection is provided. A multi-algorithmic approach uses an algorithm to detect bolted faults based on a direct comparison of the current and a threshold value, and an additional algorithm to detect current overloads based on a comparison of a peak-to-peak current and an additional current threshold.

Abstract: A combination current sensor and relay has an improved housing. In one aspect, the housing includes light emitting diodes on an upper surface that indicate open circuit and short circuit conditions. In another aspect, the housing includes a securement structure for a circuit board that includes the transformer and switches for device operation, together with aligned openings therein for routing wires to external devices. In another aspect, a multiple position switch is included on the upper surface that indicates multiple modes of operation of the device. In another aspect, the housing may be assembled in multiple parts by affixing a first portion to a support, a circuit board to the first portion, and a second portion to the first portion. In another aspect, the housing is suitable for engagement to alternatively a junction box and a duplex box. In another aspect, the configuration of the upper surface provides usability advantages.

Abstract: A lamp ballast for energizing a lamp has short circuit protection. The lamp ballast contains a transformer that provides an output voltage to the lamp. The transformer has a primary winding, a secondary winding, and a third sense winding. The third sense winding has an output that provides an indication of transformer output voltage. A reference voltage circuit creates a reference voltage that provides an indication of a non-short circuited lamp ballast condition. A comparator compares the reference voltage and the output of the third sense winding to provide an indication if the third sense winding output is below the reference. This indicates if there is a short in the output of the lamp ballast. The secondary is wound on multiple sections of a bobbin with one section being a low voltage section. The sense winding is wound under the secondary in the bobbin secondary low voltage section.

Abstract: A method and apparatus is disclosed herein for protecting a power circuit within a first cycle after power up using a current transformer to sense current and an electronic trip unit having a first trip threshold value at power up and a second trip threshold value for the reference value at about the first half cycle of the first cycle after power up. The first and second trip threshold values are threshold values used to determine an over-current condition at different preselected times after powering up is initiated.

Abstract: A residual current device includes a first delayed-tripping fault-current tripping circuit for alternating and pulsed fault current, and a second fault-current tripping circuit for direct fault current, which are connected in parallel with one another to a control line of a release for a circuit breaker, with first decoupling circuit being provided for electronic decoupling of the first fault-current tripping circuit from the control line.

Abstract: The trip device with phase reconstitution comprises a processing unit comprising means for phase reconstitution receiving signals representive of the current signals supplied by sensors. The means for phase reconstitution comprise means for determining signals representative of the amplitudes of the current signals supplied by the two sensors, means for determining a signal representative of a phase shift between signals representative of the signals supplied by the two sensors and means for determining a signal representative of a phase current reconstituted according to the signals representative of the amplitudes and to the signal representative of a phase shift of the signals supplied by the two sensors. The circuit breaker comprises such a trip device.

Abstract: A leakage current protection device, such as a ground fault circuit interrupter (GFCI), is provided that can be used in single phase or polyphase systems, with a range of input voltages from 70 to 264 volts AC, frequencies of 50 or 60 hertz, and ground fault trip currents of 6 to 30 milliamperes. A leading power factor circuit is connected to the secondary winding of the GFCI differential transformer to permit the magnetic circuit to respond to pulsating DC signals. Provision is made for continuing to provide GFCI protection in the event of an open neutral lead, with a timing circuit to prevent current flow to the ground lead until current flow in the neutral lead is completely discontinued. Various types of circuit interrupting devices, such as a circuit breaker or a power converter, may be selectively utilized.

Abstract: A secondary ground fault protection for a high voltage power supply has a high voltage transformer with a center tapped secondary coil. The primary coil of a monitoring transformer is connected to the secondary coil at the center tap, which is approximately the midpoint of the secondary coil. The power supply load is connected across the end terminals of the secondary coil. The monitoring transformer is connected between the center tap and an earth ground on the primary coil side and between sensing circuitry and a digital ground on the secondary side. The sensing circuitry includes sub-circuits to generate various outputs which indicate the presence of faults, including a floating ground, excessive fault current or an open sensor transformer. The circuit outputs can be combined using a logical OR gate to cause specific actions in response to each detected fault, including terminating the high voltage generation in response to an excessive fault current.

Abstract: In one aspect of the present invention, a residential circuit breaker is presented. The residential circuit breaker comprises an electronic residential circuit breaker having a selectable current rating which permits the user to easily set and reset the current rating depending upon the desired use and environment in which the current breaker is to be used. In another aspect, common power line carrier (PLC) communications are used to provide an effective signaling system for load control. In yet another aspect of the present invention, an interface between the electrical infrastructure and a home automation system for the purpose of load control is provided.

Abstract: A genset controller that is configurable for controlling a variety of types of gensets, as well as a method of configuring a genset controller for controlling a genset, are disclosed. The genset controller includes a memory for storing a plurality of software routines, a personality profile data set, and a user-settable data set, and further includes a processor coupled to the memory for executing the software routines and reading data from the personality profile data set and the user settable data set to control the genset. The genset controller additionally includes an input port coupled to the memory for enabling changes to the personality profile data set and the user-settable data set to be downloaded into the memory. The personality profile data set and the user-settable data set include data that configures the genset controller for operation with a particular genset.

Abstract: A thermal management of a computer system may be advantageously obtained by predicting temperature variations based upon past temperature readings. Such a system may, in preferred embodiments, filter the past temperature data to provide a more precise value, allow for a floating trip level that will change with the rate of temperature change and even allow for prediction of the amount of time left before a system shutdown may occur.

Abstract: An arc fault detector, as a stand alone device or in combination with a circuit interrupting device such as a ground fault circuit interrupter (GFCI), protects from potentially dangerous arc fault conditions. The device utilizes line side and load side pickup coils to distinguish between arc faults occurring on the line or load side. An arc fault circuit interrupter (AFCI) circuitry portion of the device shares components from the GFCI circuitry portion, and utilizes the electromechanical power carrying portion of the GFCI, including AC line disconnect circuitry and a power supply. The AFCI employs quantitative detection using variable gain control in combination with either a load disconnect or audible/visual alarm indication. The device also includes a timer circuit, which permits the user to temporarily inhibit or disable the arc detection, and selective frequency filtering permitting arc detection in the presence of power line carrier communications.

Abstract: A measuring system for monitoring power consumers in an electrical circuit. The system measures the current intensity in the circuit. A comparator compares the current intensity to a predetermined threshold value and emits a signal if the threshold value is exceeded. A signalizer provides a visual or audible alarm when a person exits the monitored area without deactivating the system.

Abstract: In a three-phase switchgear apparatus having two adjacent poles per phase, the inner pole of each side phase is equipped with a magnetic compensation circuit designed to optimize the current distribution between the two poles and of each side phase in balanced three-phase operation. This arrangement enables the currents flowing in the two poles of either of the side phases to be balanced, by specifically reducing the current intensity and temperature in the inner pole of the side phases.

Abstract: A programming device and a programmable circuit breaker are provided for switching off electric current. The circuit breaker comprises a mechanism (208) to monitor the strength of electric current in a switching mechanism (210) to switch off the passage of the electric current through the circuit breaker. To enable versatile timing of electric appliances, the circuit breaker includes a device (218) to store one or more desired time periods, an interface (220) to a separate program device of the time periods, and a control device (216, 220) to control the switching element (210) on the basis of the time period stored.

Abstract: A residual current device includes a residual current tripping circuit for actuating a release, and an additional monitoring device for checking the release, in which case a device is provided for electrically decoupling the residual current tripping circuit from the monitoring device.

Abstract: Output protection for arc discharge lamp ballasts is provided by applying sampled ballast current to a burden capacitor selected to present a low impedance across the winding to a substantially symmetrical waveform of the sample current. Asymmetry between the positive and negative half-cycles of the sample waveform, such as partial rectification caused by abnormal lamp operation, results in charge buildup across the capacitor. Sufficient charge buildup actuates a ballast disabling switch such as a silicon controlled rectifier.

Abstract: A device for sensing an alternating current includes a circuit board on whose surface is arranged a planar conductor path in which a current to be measured flows. Applied on the opposite surface of the conductor path is a planar coil in which the change in the current to be measured induces a voltage. The device is advantageously used in a converter having a direct-current voltage link circuit.

Abstract: A ground fault circuit interrupter has a residual current transformer (7) which is connected via evaluation and tripping electronics (6) to a open circuit shunt release (3), the open circuit shunt release (3) via a breaker mechanism (5) actuating the main contacts (10) in the leads (L1, L2, L3) to be monitored, the line voltage supply of the evaluation and/or tripping electronics (6) and/or the open circuit shunt release (3) being connected electrically separably to a least two leads (L1, L2, L3, N) via auxiliary contact apparatus (8). In this way the line voltage supply for the evaluation and/or the tripping electronics (6) and the open circuit shunt release (3) can be interrupted independently of the line-side or load-side terminal with respect to the main contacts (10) and is still ensured when one or two leads (L1, L2, L3, N) are interrupted.

Abstract: A combined ground fault and arc fault circuit interrupter includes a differential current transformer, a hot electrical line and a neutral electrical line passing through the current transformer and forming the primary thereof, an asymmetrical current transformer having a core through which the hot and common electrical leads pass, and a secondary wound on the core for producing a signal more strongly responsive to the current in the common line than in the hot line. An arc fault detector is connected to the secondary of the second transformer, while a ground fault detector is connected to the secondary of the first transformer, and the outputs of the ground fault and arc fault detectors are both connected to a circuit interrupter arranged for disconnecting the circuit when either a ground fault or an arc fault is detected.

Abstract: Electrical protection device for a railroad vehicle, including electrical energy consuming units 6, 7 and electrical power supply means 1 to 5, electrical energy being supplied on at least two liner electrically separated from the ground formed by the vehicle as a whole, in particular its chassis and the electrically conductive parts connected to it. The electrical protection device includes detector means 50 for detecting a short circuit alternating current flowing from one of the two power supply lines to ground, to detect any short circuit between the other power supply line and ground.

Abstract: The protective equipment switch comprises a mechanical switching contact (2) for a conductor (S1-S3), a latchable switch latch (6) for the switching contact (2), an overcurrent sensor (3) associated with the conductor, and an electromechanical undervoltage relay (7) whose exciting voltage is derived from the conductor voltage and which in its excited state latches the switch latch (6). In the case of overcurrent, the overcurrent sensor (3) causes the separation of the undervoltage relay (7) from its exciting voltage which also drops in the case of undervoltage. Thus both in the case of overcurrent and in the case of undervoltage, unlatching of the switch latch (6) is caused by the same component, namely by the undervoltage relay (7). Preferably the overcurrent sensor (3) is formed by the combination of a current transformer signal with an electronic circuit which itself is preferably an integrated circuit.