Abstract: Supply device for providing electrical energy to a consumer electrical circuit, containing a protection and monitoring device (50) assigned individually to the consumer, to the output of which the consumer electrical circuit can be connected via connecting means (10), wherein the protection and monitoring device (50) has sensor means (31, 32) for detecting at least one electrical quantity, and an analysis device (52) controlled by the sensor means (31, 32), which contains parameterisation means for specifying in a predefinable manner at least one safety relevant triggering criterion, wherein on the at least one safety relevant triggering criterion being reached, a switching device (54) for the consumer electrical circuit can be controlled.

Abstract: A circuit breaker system for providing thermal protection to a conductor conducting current from a power source to a load. While the power source is connected to the load, a microcontroller is powered by the current passing through the conductor to thermally model the temperature of the conductor. If the microcontroller determines that the temperature of the conductor has risen to an undesirable or unsafe level, the circuit breaker disconnects the power source from the load and the current no longer passes through the conductor. With no current passing through the conductor, the microcontroller no longer receives power from the conductor. Instead, the microcontroller continues to model the temperature of the conductor as the conductor cools to an ambient temperature by receiving power from an energy storage device. Accordingly, the microcontroller continuously models the temperature of the conductor until the temperature of the conductor cools to the ambient temperature.

Abstract: Current transformer relays having dual functions as current transformers and electromechanical switches are described. The current transformer relay includes a relay coil and a conducting loop concentric with the relay coil. Additional functions are thus provided in addition to the main relay switching function or functions. The concentric nature of the relay coil and the conducting loop create a current transformer between these elements. The additional functions include the ability to measure an alternating current (AC) current conducted by the conducting loop, the ability to detect and interpret an information signal imposed on power lines connected to the conducting loop, the ability to induce or impose an information signal on the conducting loop for transmission to power lies connected to the conducting loop, and the ability to measure a differential current between currents carried by the conducting loop and a second concentric conducting loop.

Abstract: Systems and methods for limiting heating to prevent explosions in a gaseous environment containing an industrial control system are described. A method may include controlling heating in an electrical circuit component in response to a circuit failure so as to avoid reaching a temperature at or above a flash point of a gaseous component of the gaseous environment.

Abstract: Assemblies, systems, and methods which prolong relay life by dynamically compensating the make and break contact timing between the contact points of the relay and a zero crossing point of the power supply's waveform are provided according to the present disclosure. The life cycle of the relay components are dramatically increased through the use of these assemblies, systems, and methods due to a decrease in arcing and other physically damaging phenomena between the contacts of the relay. The present disclosure also provides for assemblies, systems, and methods whereby a processor analyzes the inductive kickback effect in the relay load voltage signal and dynamically adjust the relay open time such that the inductive kickback effect is minimized. In exemplary embodiments, the systems/methods provided herein advantageously adjust the relay open time such that the relay switching time corresponds with current zero cross and do so without requiring complicated current monitoring components.

Abstract: A switch is disclosed, in particular a circuit breaker for low voltages. In at least one embodiment, the switch includes a conductor, an electronic tripping unit (ETU) which trips the switch when a current limit value is exceeded, the power supply of the electronic tripping unit including current transformers, with a first winding which is connected to the electronic tripping unit (ETU) forming the secondary side of the current transformer and the conductor forming the first primary side of the current transformer, the conductor supplying electrical power to the current transformer when the current varies over time. In order to ensure power is supplied to the tripping unit (ETU) even in modes of operation in which too little power is provided by the first winding, for example in the case of a direct current, small alternating currents, a pulsed direct current etc.

Abstract: A method for avoiding undesired, measurement error-induced protective tripping within a protection system of an HVDC transmission system. State variables of components of the HVDC transmission system are detected by first measuring devices to obtain a first set of measured values and by further measuring devices, which are designed in redundant fashion with respect to the first measuring devices, to obtain further sets of measured values. The first and further sets of measured values are supplied to a closed-loop control unit and a protective unit. The protective unit checks the first set of measured values for the presence of a risk of protective tripping by way of internal logic, and the closed-loop control unit regulates the HVDC transmission system as a function of one of the further sets of measured values.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: Electronic circuit breakers and systems for isolating a load from a power-supply unit are provided. One electronic circuit breaker includes a current sensor, a switching element coupled to the current sensor, and a switch controller coupled to the current sensor and the switching element. The switch controller is powered by the power-supply unit and is configured to switch OFF the switching element when the current sensor detects an amount of current from the power-supply unit greater than a predetermined amount. An electronic system includes a power-supply unit, a load, and the above-referenced electronic circuit breaker coupled to the power-supply unit and the load.

Abstract: The present invention may provide a surge current sensor and a surge protection system that deploys one or more surge current sensors. The surge current sensor may be placed on or near to a conduit, and it may be used for sensing the surge current conducted therein. The surge current sensor may include a current transformer and a processor. The current transformer may be used for receiving a magnetic flux generated by the surge current and transforming the received magnetic flux to a voltage. The processor may be coupled with the current transformer, such that it may be configured to generate a digital signal based on the voltage. Once the digital signal indicates that the magnitude of the surge current has exceeded a predefined threshold, the surge protection system may initiate a surge protection mechanism.

Abstract: The present invention is directed to a protective device configured to be disposed in an electrical distribution system between a source of electrical power and an electrical load. The electrical distribution system includes at least one line hot conductor, a line neutral conductor, and a line ground conductor. The line neutral conductor is connected to the line ground conductor at a termination point in the electrical distribution system. The electrical load includes at least one load hot conductor, a load neutral conductor, and a load ground conductor, the device comprises a conditioning circuit configured to monitor a differential current flowing through the plurality of line termination elements and configured to generate a conditioning signal in response thereto. The conditioning signal propagates in a path formed by the line neutral conductor and the line ground conductor to thereby reduce a differential current propagating in the at least one line hot conductor and the line neutral conductor.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: Various systems, methods and apparatus are described for detecting an excessive or faulty ground current in a conductive wire or electronic device. A ground current detector is coupled to a known earth ground to determine whether other ground lines are carrying excessive, faulty and/or leaking currents. If these types of unsafe conditions are detected, then a user can take appropriate action to locate and correct these problems.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: Low current electrical devices can be protected by a status relay having an active current sensing circuit that includes a current switch.

Abstract: An automatic power-off protection apparatus includes an alternating current (AC) input; an AC output connected to the AC input via power wires that comprises a naught wire and a live wire; a switching unit for enabling and disabling a connection between the AC input and the AC output; a first pair of coupling coils for producing a first induced AC voltage; a second pair of coupling coil for a second induced AC voltage; an operational amplifier for amplifying a voltage difference between induced voltages across the first secondary coil and the second secondary coil; a first and second comparator for comparing the amplified voltage difference with a first reference voltage and a second reference voltage respectively. The automatic power-off protection apparatus cuts off the path between the AC input and the AC output when detecting current leaks.

Abstract: A leakage current protection plug includes a plug housing, a power supply cord, two copper legs embedded within the plug housing, a leakage current protection device composed of two main moving contacts. A reset button presses the moving contacts to contact the two copper legs, a winding assemble, an iron core, a circuit board assemble, an ZCT. Ends of moving contacts are arranged with contacts that conduct individually with the two copper legs upon coming into contact; the power supply cord, through the ZCT, is connected with the moving contacts; the output of the ZCT is connected with the input of the amplification circuit on the circuit board, while the output of the amplification circuit is connected with the winding assemble.

Abstract: This invention relates to a power supply circuit protecting method and a power supply circuit protecting apparatus. The apparatus is provided with a power supply circuit for converting a voltage from a three-phase alternating current inputting power supply into a predetermined voltage, and an output operation circuit for performing a predetermined operation by adopting an output voltage from the power supply circuit as input. In the apparatus, based on a current value on the input side or the output side of the power supply circuit, abnormality of the supply voltage is judged, and when there is an abnormality, the output operation circuit is controlled.

Abstract: A protective device is disclosed for combination with an electrical switching device including a main current line or for integration in such a switching device. In at least one embodiment, the protective device includes a switching element and a switching apparatus, which is provided for the actuation of the switching element and is influenced by a current flow through the main current line. In at least one embodiment, in order to influence the switching apparatus, a current transformer is integrated in the main current line and an electrical resistance of a secondary winding surrounded by the current transformer can be measured. A method for operating a protective device is also disclosed wherein the switching apparatus is triggered so as to actuate the switching element if the measured resistance reaches or exceeds a predetermined or predeterminable threshold value.

Abstract: An object of the present invention is to provide a disconnector that satisfies applying a lightning surge current, blocking a follow current, being capable of short circuit breaking, and being compact in size and an overvoltage protection device combining the disconnector with overvoltage protectors. The disconnector of the present invention comprises: a current transformer that detects a current flowing through electric wires; a rectifying part that rectifies the current outputted from the current transformer; a charging part that charges the current outputted from the rectifying part; a switching part that disconnects the electric wires upon driving; and a trigger part that drives the switch when the charge stored in the charging part becomes a predetermined drive area. In this regard, the drive area is set larger than the charge that can be stored in the charging part by a lightning surge current.

Abstract: The present invention provides an electrical power distribution system that includes a first primary distribution panel (PDP) connected to a first source of electrical power and a second PDP connected to a second source of electrical power. The second PDP is connected to the first PDP by a conductor. A first ELCU receives signals corresponding to the flow of current through the first PDP to a load. A second ELCU receiving signals corresponding to the flow of current between the first PDP and the second PDP and a third ELCU receives signals corresponding to the flow of current between the second PDP and the first PDP. The first, second and third ELCUs protect the electrical power distribution system from a variety of fault conditions.

Abstract: The invention relates to an electronic trip device and a circuit breaker equipped with said electronic trip device, said trip device comprising at least one current sensor, an actuator, and an electronic processing unit to control said actuator, wherein the electronic processing unit comprises means for monitoring the state of connections of the at least one current sensor and/or of the actuator, and display means for displaying the operating state of the trip device, the means for monitoring acting on the display means to display the state of connections of the at least one current sensor and/or of the actuator. The invention also relates to a method for monitoring the state of connections of an electronic trip device comprising monitoring of the state of the connections and control of display of the state of the connections.

Abstract: A switching device for disconnecting and switching at least one line of a power supply is disclosed. The switching device may be, for example, a residual-current-operated protective device or a combination switch and includes a line-voltage-independent trigger device, a trigger element, such as a trigger relay, associated with the line-voltage-independent trigger device, as well as a line-voltage-dependent trigger device. The line-voltage-dependent trigger device has means for triggering the trigger element that is associated with the line-voltage-independent trigger device. The switching device has a simple construction, a reduced number of components, and also an enhanced functional reliability compared to a conventional switching device.

Abstract: The present invention provides an electrical power distribution system that includes a first primary distribution panel (PDP) connected to a first source of electrical power and a second PDP connected to a second source of electrical power. The second PDP is connected to the first PDP by a conductor. A first ELCU receives signals corresponding to the flow of current through the first PDP to a load. A second ELCU receiving signals corresponding to the flow of current between the first PDP and the second PDP and a third ELCU receives signals corresponding to the flow of current between the second PDP and the first PDP. The first, second and third ELCUs protect the electrical power distribution system from a variety of fault conditions.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: A method of breaking an overcurrent is provided to connect an overcurrent breaking controller in series between an AC power and a load. Thus, when detecting the connected load of which the current generated with the consumed power is higher than a rated current of the overcurrent breaking controller, the overcurrent breaking controller instantly stops the load working, when detecting the current passing through the load that is lower than the rated current, the controller allowing the load to re-work. Thus, the load of which the rated current exceeds is prevented from being replaced, and automatic power shut and recovery are implemented for protection, power saving, easy installation, and energy waste prevention.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: A power controller is positioned within a current path between the line side and the load side of an electrical circuit. The power controller closes the current path in the presence of a control supply and opens the current path in the absence of the control supply. A power supply electrically connected to the current path provides the control supply. A sensor system receives power from the power supply, monitors the current in the current path and outputs a sensor signal indicative of a current condition within the current path. A logic controller also receives power from the power supply, receives the sensor signal and removes the control supply from the power controller when the sensor signal does not satisfy an established criteria. The sensor system may include one or both of an imbalance sensor for monitoring the current balance among two or more electrical lines and over-current sensors for monitoring current in individual lines.

Abstract: A circuit interrupter includes separable contacts, a neutral conductor, an operating mechanism structured to open and close the separable contacts, and a plurality of current sensors structured to sense at least current flowing through the separable contacts. Each of the current sensors includes a primary winding and a secondary winding, the primary winding being electrically connected in series with the separable contacts. A trip mechanism is structured to cooperate with the secondary winding of the current sensors and the operating mechanism to trip open the separable contacts. A test circuit tests the current sensors and the trip mechanism. The test circuit is structured to apply a test signal directly to the secondary winding of each of the current sensors.

Abstract: One embodiment of the present invention provides a system that detects changes in power-supply current within an integrated circuit (IC) chip. During operation, the system monitors an induced current through a detection loop. This detection loop is situated at least partially within the IC chip in close proximity to a power-supply current for the IC chip, so that a change in the power-supply current changes a magnetic field passing through the detection loop, thereby inducing a corresponding current through the detection loop. The system then generates a control signal based on the induced current, so that changes in the power-supply current cause the control signal to change. In addition, the system uses the control signal to control circuits within the IC chip.

Abstract: The present disclosure provides a method and system for mounting a current transformer in proximity to a circuit breaker of an electrical system. Generally, a sensor assembly contains a plurality of current transformers (CTs) for measuring power wires from a main power supply. To accommodate measuring a greater number of wires than one sensor assembly can service, a plurality of sensor assemblies can be mounted end-to-end. The sensor assemblies can have symmetrical recessed portions that laterally align when mounted end-to-end by inverting one of the sensor assemblies. The lateral alignment allows CTs mounted lateral to the recessed portions to be aligned with corresponding circuit breakers, so that wires passing from the circuit breakers are aligned with the CTs, reducing bending stresses on the CTs in contrast to prior efforts. Changes in polarity caused by the inversion can be adjusted by software, firmware, hardware or a combination thereof.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: A method and a circuit are disclosed for amplifying the input signals of an electronic overcurrent release of low-voltage circuit breakers with a selectable amplification factor. The electronic overcurrent release includes at least one integrating condenser on the input side, and at least one pre-amplifier and a microprocessor. According to at least one embodiment of the invention, a resistance is coupled to a switch in series, parallel to an integrating condenser, and the switch is switched by way of the microprocessor in a pulsewidth-modulated manner. In this way, the effectively active resistance value of the inserted resistances is inversely increased proportionally to the pulsewidth repetition rate, thus obtaining an extremely wide regulating range.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: A device for monitoring a leakage current of a surge arrester has a measuring element for detecting a leakage current in a leakage current circuit. A filter assembly filters the leakage current in order to extract a third harmonic oscillation which is evaluated by an evaluation circuit with respect to the value thereof. The evaluation circuit delivers at least one warning signal to a display device. In a preferred embodiment, three display devices operating as a signaling light are provided. A power supply for the used circuits is obtainable by way of a transformer which extracts a necessary auxiliary zero-potential energy contained in the leakage current and with the aid of a main power supply unit connected to the transformer.

Abstract: A multiple function safety compliance test instrument includes a high voltage output switching relay protected by a solid state in-line circuit breaker.

Abstract: An electronic filter for filtering the output signal of a current sensor of a circuit breaker is disclosed. The current sensor has an output signal characteristic similar to that of a Rogowski coil output signal characteristic that includes a third harmonic noise component in response to a switching primary current of the circuit breaker, and the circuit breaker has an electronic trip unit with an instantaneous pick-up setting responsive to the output signal of the current sensor. The electronic filter includes a first stage and a second stage. The first stage has a first transfer function that defines first characteristic poles and permits passage of the third harmonic noise component. The second stage has a second transfer function that defines second characteristic poles and filters the third harmonic noise component.

Abstract: An apparatus and a method of detecting arc faults that have reduced susceptibility to nuisance tripping. The apparatus includes a current sensor, a differential current input sense circuit, a differential current (di/dt) characteristics sense circuit, an absolute current input sense circuit, an absolute current characteristics sense circuit, a power supply, a tripping circuit, a processing unit, and an electromechanical interface. The di/dt characteristics sense circuit provides information relating to the characteristic di/dt signature of a power line current. The absolute current characteristics sense circuit provides information relating to the absolute current waveform characteristics of the power line current. The processing unit correlates the di/dt characteristics to the absolute current characteristics to distinguish between electrical arc faults and nuisance loads, thereby reducing the susceptibility of the apparatus to nuisance tripping.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: A protection device for monitoring current in a power cable to an electrical device and for controlling a remotely located starter for the electrical device in response to a system controller. The device includes a transformer magnetically linked with the power cable to produce a voltage signal in response to the presence of a changing current within the power cable. An input circuit located in a single housing together with the transformer is electrically connected to the transformer so as to receive the voltage signal. The input circuit produces, in response to the voltage signal, either a first signal or a first circuit condition at the output terminal of the input circuit, representative of the changing current in the power cable. A switch circuit also in the same container with the transformer has a terminal for sensing either a second signal or a second circuit condition of the remotely located system controller.

Abstract: A circuit breaker includes current detectors, a microprocessor-controlled tripping device, and a bypass circuit that interacts with a watchdog circuit that monitors the proper functioning of the microprocessor. A switchable reference voltage is made available to the bypass circuit as a function of the momentary supply voltage. During short circuits, the bypass circuit, immediately upon being switched on, responds to very high limit current values, whereas after the switch-on phase, it already responds at moderately high limit current values.

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 (?) 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: In an overload current protection device for cutting off power from a power supply to a load (3) such as a motor by means of a contactor (switch) (2) at overloading, an MI element having a magnetic impedance (MI) effect as current detectors (4a, 4b, and 4c) is installed at a position capable of detecting a current flowing through the secondary winding of power supply transformers (5a, 5b, and 5c) that generate a control power supply to thereby reduce costs without using a constant voltage power supply and expand a current detection range by eliminating magnetic saturation due to a core, a problem with a conventional current transformer, thereby providing at low costs a high-precision overload current protection device having a wide current detection range.

Abstract: An electronic fuse comprising an integrated circuit having a control output terminal coupled to a control electrode of a power semiconductor switching device, the power semiconductor switching device being coupled in series with a load between first and second potentials, the integrated circuit further comprising a current sense input for sensing the current through the power semiconductor switching device, the integrated circuit further comprising a driver circuit for driving the power semi-conductor switching device, the driver circuit being coupled to a current limiting circuit responsive to the sensed current in the power semiconductor switching device, the current limiting circuit controlling the driver circuit whereby if the current through the power semiconductor switching device exceeds a predetermined threshold, the current limiting circuit generates a command to pulse the power semiconductor switching device on and off in a period of pulsed operation to maintain the current in the power semiconducto

Abstract: A method for current limiting of an output of a DC-to-DC converter begins by determining a current loading duty cycle of the output of the DC-to-DC converter (i.e., the present duty cycle given the loading of on the output). The processing then continues by comparing the current loading duty cycle with a zero loading duty cycle of the output (i.e., the duty cycle when the output has no load). The processing continues by limiting duty cycle of the output to the zero loading duty cycle plus a duty cycle loading offset when the current loading duty cycle exceeds the zero loading duty cycle plus the duty cycle loading offset.

Abstract: FA ballast (20) for powering a gas discharge lamp (70) comprises an inverter (200) and an arc protection circuit (600). Arc protection circuit (600) monitors an electrical signal within the ballast. In response to occurrence of a disturbance in the signal, such as what occurs during output arcing, arc protection circuit (600) disables the inverter (200) for a timed shutdown period. Arc protection circuit (600) provides a timed starting period for igniting the lamp, during which time any disturbance in the electrical signal is essentially ignored and inverter (200) is allowed to continue to operate. Arc protection circuit (600) also provides a restart function for periodically attempting to ignite and operate the lamp. Arc protection circuit (600) is preferably realized using a timer integrated circuit (U1) with associated discrete circuitry, and may be adapted for use with ballasts having self-oscillating or driven type inverters.

Abstract: A suppression and protection circuit is used in conjunction with a circuit interrupter. In one configuration, a voltage clamping device such as a metal oxide varistor is utilized in a ground fault circuit interrupter product for handling transient surges and overvoltage conditions and is placed in series with a solenoid coil. The suppression and protection circuit includes a crowbar device across the line such as a header spark gap to prevent overvoltages, and a low pass filter such as an LC filter for suppressing transient surges.