Abstract: In the current limiting circuit, which is provided with: the D/A converter 2A to output the voltage signal to supply the power source onto the load 11; reversal amplifier circuit to amplify the voltage signal; capacitor 10 to absorb the fluctuation of the power source supplied onto the load 11; operational amplifier 4B to set the amplification factor of the reversal amplifier circuit; transistor 5; and resistor 3E, the current detection circuit 7 detects the current value to be inputted into the load 11, and according to the detected current value, calculates the voltage at the current detection position, and the CPU 1 sets the predetermined voltage, the comparing circuit 8 compares the setting voltage value to the calculated voltage value, and according to the comparison result, by ON/OFF-controlling the switch 9, the setting of the amplification factor of the reversal amplifier is changed.

Abstract: A hybrid 4-in-1 power controller chip for a PC mainboard which integrates a synchronous buck switching regulator to supply the CPU core voltage, a standard buck switching regulator for I/O circuits, a linear controller for the GTL bus, and a linear regulator with built-in pass transistor for a clock generator. Therefore, a hybrid power system for a PC mainboard is constructed.

Abstract: A trip unit, such as one comprising a current sensor generating a current signal indicative of current in a power circuit, an analog to digital converter converting said signal into digital form, and a controller monitoring the current signal and sensing whether an over current condition exists and whether a ground fault condition exists. In case of an over-current condition, the controller causes a trip signal to be output resulting in the power circuit being opened. In the case of a ground fault condition, the controller causes an annunciation output signal but does not generate a trip signal in the case of a ground fault condition and therefore does not cause the power circuit to be opened.

Abstract: The present invention provides a method and apparatus for alternating current (AC) power failure detection. The method includes amplifying an AC power waveform, where the amplified waveform is asserted when the AC power waveform is in a vicinity of a zerocrossing and negated at all other times; initiating a counter when the amplified waveform is asserted; and determining if the counter equals or exceeds a reference number, where the counter being equal or exceeding the reference number indicates an AC power failure. The present invention converts an AC power signal to a near digital signal, where the near digital signal is asserted when the AC power signal is in the vicinity of a zero-crossing and negated at all other times. When the near digital signal is asserted, a counter in a controller begins counting, and ends the counting when the near digital signal is negated.

Abstract: A method of determining contact wear in a trip unit of a circuit breaker and a circuit breaker employing such a method are presented. The trip unit includes a microcontroller and associated memories. An algorithm (program) stored in a memory of the trip unit calculates cumulative energy dissipated in the breaker contacts using the current signal detected at the time of separation. Measurement of cumulative energy dissipated in the breaker contacts is proportional to contact wear. Maintenance setpoints are determined based on industry standard endurance tests and alarm threshold and trip thresholds further based on industry standards are provided within the algorithm for notifying local or remote personnel of a necessary maintenance procedure.

Abstract: A circuit breaker system 10 (FIG. 1) using electronic trip units 35 is disclosed. The electronic trip units 35 are coupled to a communications bus 30 whereby the electronic trip units 35 can be reconfigured, controlled, and/or monitored by a central computer. Further, the electronic trip units 30 include a data acquisition circuit 100 (FIG. 4) that uses chopping to provide better accuracy and increased dynamic range of current measurements.

Abstract: A configurable overload relay selectively operable in a single-phase mode of operation and a multi-phase mode of operation is configured to sense current flow through power conductors. The relay is further configured to determine a parameter related to the current flow, such as average current, vector sum of phase currents, and current imbalance, based on selection of either the single-phase or multi-phase mode of operation. Regardless of the selected mode of operation, the relay can provide protection for multiple types of power conductor fault conditions, including ground faults, overloads, and phase loss. The relay further can be configured to provide a reporting signal indicative of the value of the determined current-related parameter and/or the occurrence of the fault condition.

Abstract: A method for performing a short-circuit and overload disconnection with a semiconductor component includes the steps of providing a semiconductor component having a drain, a source and a gate. The semiconductor component has a gate-source voltage applied thereto, a current flowing therethrough, and a voltage dropping between the source and the drain. The gate-source voltage at the semiconductor component is adjusted, in dependence of the current flowing through the semiconductor component, such that, after charge carriers in the semiconductor component are depleted, the voltage dropping between the source and the drain assumes a highest possible value still uncritical for the semiconductor component and for a circuit to be disconnected. An algorithm is used for the step of adjusting the voltage dropping between the source and the drain.

Abstract: A method and system for controlling power to a cranking subsystem in a device having a power source is disclosed. The method and system comprise providing at least one switch and providing at least one controller. The switch is coupled with the power source and a portion of the device. The at least one controller is coupled with the switch. The at least one controller is for controlling the switch based detection of at least one failure in the portion of the device and to account for the at least one failure in a portion of the device. In one aspect, the method and system comprise monitoring a portion of the device and determining whether at least one failure exists in the portion of the device. In this aspect, the method and system also comprise utilizing the at least one controller to operate at least one switch in order to account for the at least one failure.

Abstract: An earth protection device having an input for receiving a first signal representative of an earth fault current, a first signal processing module, and a module for processing protection functions connected to the first signal processing module. The device includes a second signal processing module connected between the input and the first signal processing module for processing the first signal representative of the earth fault current and for supplying to the first signal processing module a second signal representative of the earth fault current. In order to increase the value of the second signal over an RMS value when the fault current comprises pulses of short duration, the second signal has, at decreasing second signal values, a gradient lower than a preset gradient limiting value.

Abstract: A connection verifying trip unit includes a microprocessor circuit and a terminal electrically connected to the microprocessor circuit. A power source is electrically connected intermediate the terminal and the microprocessor circuit. The terminal is electrically connected to ground when the terminal is connected to the circuit breaker. When the terminal is disconnected from the circuit breaker, the terminal is disconnected from ground and the power source provides an input signal to the microprocessor circuit. In response to the input signal, the microprocessor unit provides an output signal indicating, locally or remotely, that the trip unit has been disconnected from the circuit breaker.

Abstract: A power switch connecting a load to an ac source is turned off when the RMS value of the supply voltage is outside selected limits and is turned back on when the RMS voltage returns to within the limits. Adaptive hysteresis is applied to the switch controller to eliminate chattering of the power switch when the voltage fluctuates around the selected limits. To this end, the selected limits are repetitively, incrementally narrowed each time the power switch is turned off and back on a selected number of times, such as twice, within a selected time interval. The RMS voltage is rapidly determined from samples gathered over ¼ cycle so that the voltages in a three phase system can be successively repetitively calculated. Phase loss is rapidly determined by checking for the leading edge of a square wave generated from the supply voltage wave form.

Abstract: In a load for testing an energy production device, such as a fuel cell, a technique is provided for sensing one or more operational parameters for each of a plurality field effect transistors. Analog and digital feedback are provided to adjust the control signal to the FETs to ensure that each remains within its individual safe operating area. The technique preferably takes all of the various operational parameters into account to determine if any individual FET is approaching the SOA boundary, and prevent that single FET from leaving the SOA while continuing to manage the operation of the entire load.

Abstract: A method of protection in an electronic trip unit is described herein. The method includes selecting a limit value. The method further includes sensing an electrical signal to provide corresponding first and second sensed signals, each indicative of an electrical characteristic of the electrical signal. The first and second sensed signals are compared to determine a rate of rise of the electrical characteristic, and the rate of rise is compared to the limit value to detect a spike in the electrical characteristic. The generation of a trip signal is withheld when the rate of rise is greater than the limit value.

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: The invention concerns a protective circuit (10) for protecting a rechargeable battery (1) against currents of too high intensity. The protective circuit (10) includes detection and comparison means (30, 31, 32) for generating a control signal (OVRC) in response to the comparison of a reference voltage (VREF) and a measuring voltage (VM) representative of the charge or discharge current (ICH, IDCH) passing through the battery (1). According to the invention, the detection and comparison means (30, 31, 32) include adjustment means (32) for compensating a temperature dependence of the measuring voltage (VM) and/or the reference voltage (VREF), these adjustment means (32) including means for generating diode voltages (VBE1 to VBE5).

Abstract: A signal correction apparatus includes: a measurement signal generator for generating a measurement signal; a reference signal generator for generating a reference signal; a signal processing section for processing the measurement signal and the reference signal; a signal measurement section for measuring at a first time the reference signal having been processed by the signal processing section, measuring at a second time the reference signal having been processed by the signal processing section, and thereafter measuring the measurement signal having been processed by the signal processing section; and a correction section for performing a correction on the measurement signal having been processed by the signal processing section and measured by the signal measurement section, based on a change from the reference signal having been processed by the signal processing section and measured at the first time to the reference signal having been processed by the signal processing section and measured at the secon

Abstract: A method and system for synchronizing the sampling frequency, at which power system data is sampled, with the frequency of the power system. Adjustments to the sampling frequency can be made by comparing first and second derivatives to threshold values.

Abstract: Electrical equipment is safeguarded from damage due to faults by a circuit that provides several levels of protection. A semiconductor switch and a current sensor are placed in series with the electrical equipment. When the current to the equipment exceeds a first threshold for a predefined period of time, the semiconductor switch is rendered non-conductive until the circuit is specifically reset. When the current to the equipment exceeds a greater second threshold, a pulsed signal alternately places the semiconductor switch in conductive and non-conductive states so that the average current applied to the equipment is within an acceptable level. Should the current exceed an even greater third threshold, the semiconductor switch is immediately rendered non-conductive until the circuit is manually reset.

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 controller. 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: 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: 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: An electronic protective relay emulates an electromechanical protective relay so that operation of the two types of relays can be coordinated in providing protection in an electric power distribution system. The electronic protective relay incorporates a digital processor which increments a variable delay tally as an inverse current function and a fixed delay tally by a corresponding proportionate amount. During each running of the routine, only the smaller of the two tallies is increased so that they are forced to track one another. When both tallies reach a trip value, a trip signal is generated. The processor also applied a reset function when the measured current is below a pickup value. In accordance with the preferred reset feature, the variable delay tally is reduced using an inverse current function and the fixed delay is reduced by the same amount.

Abstract: In a load for testing an energy production device, such as a fuel cell, a technique is provided for sensing one or more operational parameters for each of a plurality field effect transistors. Analog and digital feedback are provided to adjust the control signal to the FETs to ensure that each remains within its individual safe operating area. The technique preferably takes all of the various operational parameters into account to determine if any individual FET is approaching the SOA boundary, and prevent that single FET from leaving the SOA while continuing to manage the operation of the entire load.

Abstract: The communication device comprises a central unit and at least one station connected by a network. The station comprises a checking circuit and a storage circuit connected to the checking circuit. The storage circuit stores data representative of information which the station has to transmit to the central unit and transmission condition parameters associated to said information. In a parameter setting phase, the station receives the data and parameters to be stored. Then, in an operating phase, the checking circuit transmits information according to the stored transmission condition parameters.

Abstract: A circuit breaker system (100) providing a low impedance magnetic latch tripping scheme. The circuit breaker system (100) includes a trip unit (310) coupled to a switch unit (108). Trip unit (310) is coupled to an electrical circuitry and utilizes a current transformer (114) to sample a current conducting through the electrical circuitry. This current is processed into an input signal (126) suitable as an input to a trip circuitry (316) included in the trip unit (310). When a processor (322) senses an overcurrent condition in the input signal (126), processor (322) transmits a trip signal (128) to a switch (220) to initiate protection against the overcurrent condition, i.e., a trip of the electrical circuitry. Switch (220) permits a low release current to conduct through a low impedance electromechanical interface unit (218) such that the electromechanical interface unit (218) can actuate a mechanical opening mechanism included in the switch unit (108).

Abstract: An electronic trip unit and a method of protection in an electronic trip unit comprises selecting a limit value, sensing an electrical signal to provide corresponding first and second sensed signals, each indicative of an electrical characteristic of the electrical signal, comparing said first and second sensed signal to determine a rate of rise of said electrical characteristic, comparing said rate of rise to said limit value to detect a spike in said electrical characteristic, and withholding generation of a trip signal when said rate of rise is greater than said limit value.

Abstract: A method of detecting manual trips and reclose operations in an intelligent electronic device, e.g., electronic trip unit or protective relay, is presented. The intelligent electronic device includes a microcontroller and associated memories. An algorithm (program) stored in a memory of the intelligent electronic device detects manual trips when the following conditions are satisfied: (1) no trip event message has been issued by the trip unit within the reaction time required to trip the circuit breaker; (2) current becomes zero on all phases of the line; and (3) voltage downstream from the circuit breaker becomes zero on all phases. Reclose operations are detected when load side voltages on all phases return from 0V to nominal levels of the line side of the breaker.

Abstract: A circuit breaker trip unit with user-adjustable sensitivity to current spikes (22) includes a user-adjustable switch (30), a current sensor (32), an analog-to-digital (A/D) converter (34), a microprocessor (36), and a power supply (37). The current sensor (32) is electrically connected to the distribution circuit (10) and provides analog signals indicative of current measurements in the distribution circuit (10) to the A/D converter (34). The A/D converter (34) converts the analog signal to a digital line signal and presents the digital line signal, via a bus (38), to the microprocessor (36). The user-adjustable switch (30) is arranged to provide a signal indicative of a limit value, via a bus (40), to the microprocessor (36). The microprocessor (36) comprises a plurality of registers (42-48) and ROM (50) internal thereto. The ROM (50) includes trip unit application code, e.g., main functionality firmware, including initializing parameters, boot code, and a short circuit protection algorithm.

Abstract: An overcurrent protection circuit for input/Output (I/O) buffers for a Field Programmable Gate Array wherein short circuits can be detected and the output current limited so as to avoid damaging the device. I/O buffers having the overcurrent protection circuit can detect a contention between the buffers. In order to eliminate the contention, certain I/O buffers will go into a noncontending state.

Abstract: A sensing and control circuit for power line shorts works especially well for sensor or actuator devices controlled through a microcontroller. A power control circuit is placed between a pin of a programmable microcontroller and a sensor or actuator device to act as a short detector and switch to control power to the device. A capacitor in the power control circuit is charged and sensed by a single pin of the microcontroller to regulate a transistor which switches power to the device.

Abstract: A method and apparatus for providing a more reliable protection device and an improved PIC power integrated switch. Accordingly, the over-temperature status of the switch as well as the overcurrent status of each of a plurality of ports of the switch are detected. If there is over-temperature, ports with the overcurrent status are identified as a potential cause. These ports are then switched off. After a predetermined waiting time period during which the switch temperature is expected to decrease, the over-temperature status of the switch is again checked. If the over-temperature disappears, then the ports with non-overcurrent status remain on. However, if the over-temperature persists, then all of the ports are turned off. The improved PIC switch thus increases the dynamic operation range of the conventional PIC switch, while ensuring normal operations.

Abstract: A substation for distributing electric power includes protective relays whose trip points are made to be a function of temperature, the protective relays being used to control the opening and closing of circuit breakers for protecting against fault conditions in at least one of the power input and power output portions of the power distribution system. In one embodiment, a temperature probe which is used to sense the temperature at a selected point of the substation supplies the temperature information to a microcontroller which is programmed to set the trip point of selected protective relays as a function of the sensed temperature.