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: The invention relates to a method, a computer program and a device (20) for the plausibility checking of current transformers (7) in an electrical switchgear assembly (1) and to a switchgear assembly (1) having such a device (20). According to the invention, zones (1a, 1b, 1c) bounded by current transformers (7) and possibly by open switches (3-5) are detected for an instantaneous topology of the switchgear (1), in each zone (1a, 1b, 1c) the signed current measurement signals are added and in the case of significant deviations of the current sum from zero, all current transformers (7) of the associated zone (1a, 1b, 1c) are identified as being problematic. Exemplary embodiments relate to, among other things: a warning counter (2e) for problematic current transformers (7); in the case of a defective current transformer (7), an operation with calculated currents or an automatic combining of zones (1a, 1b, 1c); and coordinating the plausibility test with switching actions.

Abstract: An arc fault detector system detects arcing faults in an electrical distribution system by monitoring one or more conductors and producing an input signal representing one or more electrical signal conditions in the circuit to be monitored. This input signal is processed to develop signals representing the electrical current flow through the monitored circuit and broadband noise signal components. The system analyzes these signals to determine whether an arcing fault is present, and if so, outputs a trip signal which may be used directly or indirectly to trip a circuit breaker or other circuit interruption device.

Abstract: A voltage regulator having an output terminal adapted to being connected to a load, including a device for limiting the current flowing through the load to a first threshold current if the voltage of the output terminal is lower than a threshold voltage, and to a second current threshold higher than the first current threshold if the voltage of the output terminal is greater than the threshold voltage.

Abstract: A miniaturized cost-saving intermittent short circuit determining device located between a power source and an electric load in a vehicle electric circuit. The determining device includes detecting means for detecting current flowing through the electric circuit, determining means for determining whether the current detected by the detecting means is an intermittent short circuit, and disconnecting means for disconnecting the electric circuit when the determining means judges that there is an abnormality. The determining means is connected to an external switch circuit, which selectively supplies and stops current to the electric load of the electric circuit. The determining means determines whether the external switch circuit is switched on or off, and switches the disconnecting means on or off according to the determination.

Abstract: A digital directional relay converts a voltage value and a current value of a power system into digital voltage data and digital current data by periodic sampling and determines a direction of a fault using the digital voltage data and the digital current data. In the digital directional relay, a variation in unbalanced component voltage and a variation in unbalanced component current are computed using both voltage data at a reference point in time and voltage data at a point in time elapsed from the reference point in time by a given sampling interval and using both current data at reference time and current data at time elapsed from the reference time by a given sampling interval, respectively. A relationship in phase between these variations is obtained to determine whether a forward fault or a reverse fault occurs.

Abstract: In a semiconductor relay system for supply a power source to a lamp load under the on/off control by a microcomputer using a semiconductor relay, a method of cutting off a circuit under an overcurrent, a first prescribed value is which is a current value higher than a rated load current for the load and a maximum current value supplied to the lamp load, and a second prescribed value is set which is a current value between said first prescribed value and said rated current value; the current value flowing through the lamp load is sampled at predetermined time intervals and comparing the current value thus sampled with the second prescribed value; and when a higher current than said first prescribed value flows through the lamp load, the current supplied to the lamp load is controlled within a prescribed range between said first prescribed value and said second prescribed value, and when the sampled current value higher that said second prescribed value is counted by a prescribed number of times, the sampled cu

Abstract: In a circuit arrangement for switching on a power output stage, in particular for electric motors with a high current draw, the output stage and at least one buffer capacitor connected in parallel with it are connected to an operating voltage source via a relay. A current source which supplies a limited current is connected to the at least one capacitor, bypassing the relay. A delay device is provided, which does not switch on the relay until the at least one capacitor is charged to approximately the operating voltage by the current source.

Abstract: A motor starter. The motor starter comprises a motor; start, run, shorting and transition contactors operably associated with the motor; and run, start, shorting and transition auxiliary contactors. The transition auxiliary contactor operably controls the operation of a shorting contactor, and the shorting auxiliary operatively controls the operation of the run contactor.

Abstract: A device for detecting arc fault which distinguishes harmful arc from the signal generated by operation of a dimmer and start of electronic devices. Signals outputted from a current transformer is attenuated by a resistor which is coupled in parallel to the current transformer. By the attenuation of the resistor, the signal generated by the operation of a dimmer is not determined to be arc in arc determining part. Harmful arc and the signal generated by the start of the electronic device are distinguished by integrating both signals. As the harmful arc lasts for a long time, large signals are integrated in an integrator while the signal generated by the start of electronic device does not last for a long time.

Abstract: A programmable controller has an overcurrent detection portion, an overcurrent indication portion and a transistor for interrupting a load current at the time of occurrence of an overcurrent are provided in an output circuit portion of the programmable controlled. An overcurrent detection resistor is provided in the output transistor circuit, and a detected voltage across the resistor is compared with a reference voltage in an overcurrent detection circuit to judge an overcurrent. If an overcurrent is recognized, the overcurrent indication portion is operated, and the base current of the output transistor circuit is controlled to perform protection of the output circuit from the overcurrent. Accordingly, when an overcurrent is flowing and an input signal is in ON state, the output transistor is turned OFF automatically and, the overcurrent state is showed to a user.

Abstract: An exemplary embodiment of the invention is a method for detecting a potentially locked axle on a vehicle propelled by an AC motor. The method includes conducting a speed test by estimating axle speed and comparing estimated axle speed to measured vehicle speed. The existence of a potential locked axle condition is determined based on the comparing of estimated axle speed to measured vehicle speed. Additional tests are disclosed for determining a potential locked axle condition and a sensor fault condition.

Abstract: An adaptive fusing electrical circuit (circuit) including a power supply and an electrical load drawing an electrical current therethrough. The circuit includes a current detector that measures a current level through the circuit. An interruption switch, which is normally closed, is electrically coupled to the electrical load and the current detector having an open state and a closed state. A controller is coupled to the power supply, the current detector, and the switch, the controller monitors the current level and a first circuit parameter of the electrical circuit. The controller interrupts the electrical current by switching the interruption switch from the closed state to the open state when the current level and the first circuit parameter are outside corresponding guard bands.

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 power supply device for an electronic protection unit for AC/DC low- and/or medium-voltage power networks, comprising:

Abstract: A timer circuit that utilizes the thermal runaway effect, and includes a switch, a resistor, a transistor and a protective device. The temperature of the transistor rises due to a phenomenon known as the thermal runaway effect, which causes the temperature of the transistor to rise while increasing current flow. This will eventually cause the protective device to activate. The time it takes to activate the protective device is predictable for a given transistor, therefore the circuit operates as a timer. In an alternate embodiment, a heat source is used. This heat source rises in temperature as current flows in the circuit. A heat sensor located near the heat source rises in temperature along with the heat source. A comparator compares the temperature from this heat sensor with the temperature of a heat sensor located further from the heat source. When there is a user-definable difference in temperature due to thermal diffusion between the two heat sensors, power to the transistor is disconnected.

Abstract: A circuit protects a power conversion system with a feedback control loop from a fault condition. The circuit has an oscillator having an input for generating a signal with a frequency and a timer connected to the oscillator input and to the feedback control loop. The timer disables the oscillator after a period following the opening of the feedback control loop to protect the power conversion system.

Abstract: A method of reconizing a fault current in a control unit and to a control unit having a circuit for recognizing the fault current. According to the invention, a current flowing into the control unit which could cause the control unit to be damaged or to operate incorrectly is detected and a fault signal is produced depending on the current detected, the fault signal causing the load or the current supply for the control unit to be switched off, for example.

Abstract: Circuitry for protecting a first electrical system when connected to a second electrical system via a bus which provides a current-carrying signal to the first electrical system and includes a reset signal which is monitored by the second electrical system. The circuitry includes a capacitor connected to the current-carrying signal of the bus. A first switch is electrically connected between a node of the capacitor and a ground point. The first switch is closed when the first electrical system is powered-up and open when the first electrical system is powered down. A second switch is electrically connected between the reset signal of the bus and the ground point. The second switch closes due to the energy accumulated by the capacitor when the first switch is open.

Abstract: A method and relay for magnetizing inrush restraint in protective relays for power transformers. The method utilizes the phase angle relation between the fundamental component and the second harmonic in addition to the magnitude ratio. This is accomplished by calculating and utilizing the complex second harmonic ratio. The specially shaped operating characteristic for the complex second harmonic ratio is made dynamic providing for better security without jeopardizing dependability of the transformer protective relay.

Abstract: A fuse apparatus (1) is provided for selectively interrupting a load current (Ia) flowing between a pair of associated conductor leads. The fuse apparatus includes at least two spaced apart electrically conductive contact elements (5) operatively connected with the associated conductor leads. A fuse element (7) is connected to the contact elements (5) using an electrically conductive connection material (9) to allow the current (Ia) to flow between the pair of associated conductor leads. The connection material (9) is adapted to electrically disconnect the fuse element (7) from the contact elements (5) when the current (Ia) exceeds a predetermined current intensity. The connection material (9) has an intrinsic electrical transition resistance characteristic whereby the material develops a temperature in proportion to an intensity of the current. The connection material melts as the current increases to separate the fuse element from the contact elements.

Abstract: A differential protective relay and method for a microprocessor-based bus differential protective relay that ensures fast and sensitive operation under internal fault conditions and offers improved stability during external fault and other non-internal fault conditions. The method uses a two-slope differential characteristic to cope with small CT transformation errors without reducing relay sensitivity. The method can also use a saturation detector to switch dynamically between the 1-out-of-2 and 2-out-of-2 operating mode depending whether or not the CTs saturate. In a 2-out-of-2 operating mode, both the differential and directional elements must confirm a fault for the relay to trip. In a 1-out-of-2 mode, if saturation is not detected, the relay can trip without checking the fault direction.

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 device for sensing motor current for over-current protection in an electric power tool. The tool includes an electric motor supplied with electrical power via a live cable and incorporates over-current protection including a tripping circuit with a current sensor associated with the live cable. The device includes a toroid of the sensor and two cable segments connected in parallel to a section of the live cable such that the motor current will be distributed among the cable segments and live cable section in respective proportions. The toroid extends around one cable segment for sensing the respective proportion of the motor current.

Abstract: A method for monitoring current in a power supply system including multiple parallel power supplies and current load sharing devices for each power supply. The error voltage generated by the current load sharing devices, in the process of balancing the power supply outputs, is proportional to current provided by a single power supply. The total number of power supplies may be determined by including a small current source with each power supply, and using the current sources to drive a “present” line, the current on this line indicating the number of power supplies present. The error voltage and the present line signal are used by a control circuit that includes analog-to-digital conversion and a CPU to calculate the total current drawn by the supply, and to trigger a circuit breaker if the total current exceeds a predetermined limit.

Abstract: A switching device includes a commanding device (813, Q51) which commands a driving of a load, a driving device (111) which outputs a drive signal in response to a drive command signal from the commanding device (813, Q51) and a first switching device (QA) inserted in a power supply circuit connecting a power supply (101) and the load (102). The first switching device (QA) is adapted to conduct in response to the drive signal and close the power supply circuit. A reference resistor (Rr1, Rr2) generates a reference voltage by receiving a current from the power supply, and a second switching device (QB, QC) is inserted in a shunt circuit connecting the power supply and the reference resistor. The second switching device (QB, QC) is adapted to conduct in response to the drive signal and close the shunt circuit. An abnormality determining device (CMP1, CMP2) determines an abnormality by comparing an output voltage from the first switching device (QA) and the reference voltage.

Abstract: A control apparatus for controlling multiple power loads in a vehicle includes a circuit for detecting a current abnormality of a power element and a circuit for monitoring a temperature abnormality in a locality of the power element. Circuits are also provided continuing or shutting down the power element based on information concerning the above stated current and/or temperature abnormalities, with a timing which is established according to a substantially constant period or a time interval which is stored in advance in a memory element.

Abstract: A control circuit of a switching state detecting device for a switch controls the value of a resistive element connected between one end of the switch (SW), of which the switching state is to be detected, and the power source or ground line, so the range of operating voltage can be widened, the current flowing at the time of switching on is suppressed so that power consumption of an electronic apparatus provided with the switching state detecting device for a switch is reduced, and improvement in detection precision can be made by causing the detection current to flow in a sure manner.

Abstract: A differential relay for protecting a power apparatus portion of a power system, such as a bus line, includes incoming and outgoing power lines on which incoming and outgoing currents are present. The incoming and outgoing currents of each phase are applied through current transformers and then through filtering and normalizing circuits prior to application to the differential relay. The differential relay includes a circuit for determining the presence of an external fault, and maintains security by avoiding a tripping action of the relay for said external faults.

Abstract: A circuit is provided for testing a drive stage of an actuator, such as a motor of an EPAS system. A power supply circuit comprises a contact for supplying normal drive stage current and a resistor for supplying reduced drive stage current before the normal current is supplied. A measuring circuit measures a drive stage electrical parameter such as supply voltage and a comparator compares this with an acceptable value. If the measured parameter corresponds to a current through the drive stage which is different from an expected value, a fault is signaled and the contact is prevented from closing.

Abstract: A protection circuit (30) for a Traveling Wave Tube having multiple tone operation. The protection circuit (30) is a dual sensor (52, 54) arrangement. One sensor (52) is an operational amplifier circuit (56) having a short time constant and a high threshold current. The first sensor (52) provides protection against short time scale faults. The second sensor (54) is an operational amplifier circuit (58) having a time constant higher than the first sensor (52) and a lower current threshold than the first sensor (52) to provide protection against long time scale events. The two sensors (52 and 54) are logically “OR”ed with each other and eliminate spurious shutdowns and circuit damage.

Abstract: In a motor control apparatus, a current control section (1) controls the motor current by judging whether the current value detected by the current detecting unit (4, 7, 14) is of an overcurrent level exceeding an admissible value (Tmax) or a normal level which is equal to or smaller than the admissible value. When the current value detected by the current detecting unit is of an overcurrent level, the current control section restrains the current value to be supplied to the motor irrespective of the external motor torque or speed command, and when the current value detected by the current detecting unit becomes to be the normal level, the current value to be supplied to the motor is restored to an original non-restraint level.

Abstract: A pulse-width modulator for controlling a semiconductor circuit-breaker in a switched-mode power supply has a comparator circuit for generating control pulses determined by an oscillator signal. Whereby a duration of the individual control pulses depends on a first control signal and a second control signal. A measuring configuration is provided for generating a load-current signal that is dependent on a load current of the circuit-breaker. Furthermore, the modulator has a feedback branch for feeding back the load-current signal to the comparator circuit whereby the feedback branch has a low-pass configuration. The low-pass configuration has an input which receives the load-current signal and an output at which the second control signal can be picked off.

Abstract: The intrinsically safe detection of binary signals of a sensor with a variable internal resistance is achieved by connecting the sensor to the voltage output of a d.c. voltage source via a shunt. To the voltage output is attached a multistage voltage divider with voltage comparators each being connected to its voltage taps by one input terminal each and with the other input terminals of the voltage comparators being connected to the terminal (26) of the shunt attached to the sensor. Optocouplers are provided downstream from the voltage comparators for transmitting the comparison results of the voltage comparators to an analysis unit (30).

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: This power supply system 1 comprises:

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 partial discharge (PD) coupler for coupling electrical machinery to partial discharge analysis testing equipment includes at least one capacitor capable of withstanding high voltages; a current sensor for sensing current passed by the at least one capacitor; and potting material surrounding the at least one capacitor and the current sensor for providing flashover protection.

Abstract: A current-limit circuit and a method of limiting current supplied to a load through a power transistor utilize a control transistor that is selectively activated to a conducting state to limit the current conducted through the power transistor in response to a predefined condition. The predefined condition may be a short-circuit condition or an over-current condition. The configuration and operation of the control transistor are such that, when the control transistor is in a conducting state, the current conducted through the power transistor is limited by the structural ratio of the two transistors. However, during normal operating conditions when the control transistor is deactivated to a non-conducting state, the control transistor does not degrade the performance of the power transistor. In a first embodiment, the current-limit circuit is configured to provide protection from a short-circuit condition.

Abstract: If an excess current is detected after the current in the secondary circuit of an induction generator-motor has exceeded a preset value, it is determined that a fault has occurred in the transmission line, provided that the current at the neutral point of a main transformer has exceeded a preset value. In this case, the operation of the induction generator-motor is continued. If no excess current is detected, it is determined that a fault has occurred in the secondary circuit of the induction generator-motor, provided that the current at the neutral point of the main transformer has not exceeded the preset value. In this case, the operation of the induction generator-motor is stopped.

Abstract: A system has one or more electronic devices and ports adapted to be coupled to the one or more electronic devices. Voltage regulators are each coupled to provide a voltage signal to a corresponding port. A decoder is coupled to the ports to detect if one of the ports is not coupled to an electronic device and to enable system operation even though one of the ports is not coupled to an electronic device and the voltage signal provided to the one port is not at a predetermined level.

Abstract: An arc fault detector system detects arcing faults in an electrical distribution system by monitoring one or more conductors and producing an input signal representing one or more electrical signal conditions in the circuit to be monitored. This input signal is processed to develop signals representing the electrical current flow through the monitored circuit and broadband noise signal components. The system analyzes these signals to determine whether an arcing fault is present, and if so, outputs a trip signal which may be used directly or indirectly to trip a circuit breaker or other circuit interruption device.

Abstract: A system has one or more electronic devices and ports adapted to be coupled to the one or more electronic devices. Voltage regulators are each coupled to provide a voltage signal to a corresponding port. A decoder is coupled to the ports to detect if one of the ports is not coupled to an electronic device and to enable system operation even though one of the ports is not coupled to an electronic device and the voltage signal provided to the one port is not at a predetermined level.

Abstract: An integrated circuit (IC) chip security box includes a top cover member and a bottom cover member respectively mounted to top and bottom sides of a circuit board to enclose an IC chip mounted to the circuit board. The cover members are made of conductive material for blocking radio frequency emission from the IC chip. Bolts secure the cover members to the circuit board. Conductive members are formed on one of the cover members and the circuit board and engage with each other when the security box is mounted to the circuit board thereby forming an electrical loop. Unauthorized opening of the security box breaks the electrical loop thereby causing a signal to the IC chip to initiate a purging process which deletes program codes written in the chip and prevents unauthorized copy of the codes.

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.

Abstract: A bus-bar protection relay equipment includes a data-acquisition means, a check zone protection means, a fault bus-bar judging means, and a tripping bus-bar judging means. A data-acquisition means transforms analog current signal from the current transformer connected to the bus-bar with two or more dependency regions into digital data at every predetermined cycle. The check zone protection means computes amount Id (vector sum) of operation, and the amount Ir (scalar sum) of inhibition using the digital data transformed by this data-acquisition means. The check zone protection means transforms analog current from the current transformer of a line segment into digital data “n” multiplied with. The amount Id of operation and the amount Ir of inhibition are computed. An actuating signal is outputted when predetermined relationship is satisfied by using the amounts Id and Ir.

Abstract: A circuit for and method of controlling transient currents on power conductors includes a voltage-controlled switch connected between one of the power conductors and a load. A turn-on circuit is connected to the switch to control the switch during a transition period in which the switch changes from a non-current conducting state to a conducting state in which a static current flow to the load can be maintained. The turn-on circuit controls turn-on such that the rate of rise and the peak amplitude of the current through the switch is limited during the transition period. A reset circuit also is connected to the voltage-controlled switch to reset the switch to a non-conductive state when the voltage between the power conductors drops out. The reset circuit is configured to reset the switch within a reset period having a duration that is shorter than the duration of the transition period.

Abstract: A phase control switching system for controlling opening and closing timings of a power switching device to suppress the occurrence of an exciting rush current or a make-and-break surge voltage which is severe to system equipment such as a transformer, a reactor and a capacitor bank, or for controlling an arcing time of a circuit breaker to put the circuit breaker into operation for the arcing time leading to no-re-ignition or for the optimal breaking time. In the phase control switching system, a current measuring section or a current gradient measuring section is provided to measure a current value or a current gradient value of a current to be broken or introduced, and a reference phase detecting section estimates a current zero point of a current waveform on the basis of the measurements. Subsequently, a control section, upon receipt of an opening/closing command, an opening phase control operation using an arbitrary time point after the current waveform estimation as a reference.

Abstract: A portable partial discharge detecting device for measuring partial discharge in energized electrical systems encloses a relay circuit and a DC power source. A pair of sensor circuits are enclosed within electrically coupling clamping mechanisms and are coupled to the relay circuit at sensor inputs by cabling. The clamping mechanisms engage the ground leads of the electrical system. Trip and alarm networks of the relay circuit continuously compare the picocoulomb values of the partial discharge pulses against user set threshold values. Relays coupled to the trip and alarm networks respond if the threshold values are exceeded. The alarm setting is always set to a pick-up value equal to or less than the trip setting. The trip network relays are coupled to a control circuit of the electrical system and can take the system off-line. The alarm network relays are coupled to an alarm circuit and can warn the user that a certain level of partial discharge has been reached within the electrical system.

Abstract: A switching configuration for electrical control devices, in particular for use in control devices of an electrical system of power-driven vehicles is disclosed. The switching configuration includes a busline with a defined thermal conductivity and a defined heat capacity, which is connected with a first predefined power supply potential. The switching configuration has a plurality of switching devices for switching on and off at least one associated load of a respective switching device, for each of which a first current-conducting connection of the switching device is connected with the busline with a defined thermal conductivity and a heat capacity. Whereby each load of a respective switching device is connected between a second current-conducting connection of the switching devices and a second predefined power supply potential.