Abstract: A microcontroller-based temperature compensated circuit for ground-fault circuit interrupter to meet the requirements of UL 943 using a single sensor to detect both ground-fault and grounded-neutral fault conditions in both full-wave and half-wave AC power supplies as part of a ground-fault circuit breaker or a receptacle device.

Abstract: A control circuit synchronizes an ac power inverter to the mains voltage of an electrical grid by matching the fundamental phasor components of the inverter's output voltage to the fundamental phasor components of the mains voltage. Once such matching meets an acceptable voltage error threshold, the control circuit initiates contactor closure, verifies contactor closure, and then initiates a changeover from voltage-mode control used in synchronization operations to a current-mode control of the inverter's output. The control circuit provides corresponding disconnection control when disconnection from the grid is desired, wherein the regulated power of the inverter is ramped down in controlled fashion until it reaches a lower threshold whereupon contactor opening is initiated. Once contactor opening is verified, regulation control reverts to stand-alone voltage mode control or to shut down, as needed or desired.

Abstract: A remote metering display is used for displaying power-related information generated by a power meter linked to the display. The remote metering display comprises a display screen, a plurality of user interface buttons for navigating through menu options depicted on the display screen, and a motion sensor for activating the display screen in response to detection of a person's presence within a predetermined distance of the motion sensor.

Abstract: A power inverter comprises a push-pull inverter circuit that includes a transformer having a primary winding coupled to a DC bus and a secondary winding coupled to an AC bus, main power switches coupling each end of the primary winding to a DC return, and one or more supplemental power switches coupling at least one end of the primary winding to a snubber bus. The supplemental switch at a given end of the primary winding forms a buck-mode converter in combination with the primary winding and the associated free-wheeling diode at that end of the primary winding, and can be controlled by a switching controller to effect energy transfer between the snubber bus and DC bus. The switching controller can be configured to control power flow between the DC, AC, and snubber buses by controlling the common-mode and differential-mode voltages of the primary winding via main/supplemental power switch control.

Abstract: A power metering apparatus meters a power signal in a powered system. A low-pass filter receives the power signal and outputs a filtered signal. The filter implements a corner frequency programmable based on a first clocking signal and anti-aliases high frequency components of the power signal. An A/D converter receives the filtered signal and outputs a digital signal. The A/D converter samples the filtered signal according to a system clock based on a second clocking signal. A clocking element generates and outputs each of the first clocking signal and the second clocking signal. The first clocking signal is synchronous with the second clocking signal.

Abstract: An improved filter assembly for a circuit breaker includes a generally rectilinear filter housing having at least two filter mounting zones for receiving at least two filter assemblies, so as to define, in the aggregate, a filter assembly, and at least two filter assemblies configured for interfitting with the filter mounting zones of the filter housing, each filter assembly comprising a generally rectilinear filter body having a given peripheral configuration and a filter gasket configured for interfitting about a periphery of the filter body for sealingly engaging the filter body relative to the filter housing in response to forces encountered by the filter assembly both upon assembly and in operation. The filter assembly may further have a small hole diffuser having a peripheral configuration similar to the peripheral configuration of the filter bodies, in the aggregate, when assembled with the filter housing and configured for interfitting within the filter housing.

Abstract: A system for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in the circuit includes a circuit for analyzing the sensor signal to determine the presence of broadband noise in a predetermined range of frequencies, and producing a corresponding output signal. A controller processes the sensor signal and the output signal to determine current peaks and rise times and to determine, using the current peaks and rise times and the presence of broadband noise, whether an arcing fault is present in the circuit, by comparing data corresponding to the current peaks and rise times and broadband noise with preselected data indicative of an arcing fault. The circuit for analyzing and the controller are integrated onto a single application specific integrated circuit chip.

Abstract: A communication scheme which allows Internet access to selected services behind a corporate firewall on a corporate Intranet with a publisher on the Intranet in communication with the Intranet web services and a listener on the Internet and is responsive to select requests from an Internet user which are embedded in responses received from the listener responding to queries from the publisher.

Abstract: A medium voltage controller for electrical equipment, such as motors, transformers, reactors, and capacitors, having an arc resistant cabinet, swaged internal electrical connections, a one-piece self-aligning withdrawable finger cluster, a pull-out instrument compartment, a load discharge device, cast fuse holders, disconnect switch, a switch illuminator, low power current transformers, and an optical temperature measuring system. The arc resistant cabinet relies on the pressure generated by an arc fault to provide the sealing action to contain the fault forces. The cabinet's rear panels are inside the cabinet and the panel lips mate to edges of the cabinet opening. The front doors each have a series of latching tabs along one side and a hinge along the opposing side. A dimple-in-a-dimple joint provides shear strength for panel joints. At the top of the cabinet is an exhaust vent.

Abstract: A system for determining the location of a disturbance event in a power distribution system. More specifically, the present invention provides a system for determining the direction of a disturbance event at the individual meter location and a system for analyzing this data from multiple meter locations to locate the cause of the event in the power system. The system includes a power feed bus for supplying electrical signals and a circuit monitor coupled to the feed bus. The circuit monitor is responsive to detect the disturbance event by comparing a disturbance event signal with a pre-event signal on a plurality of time scales.

Abstract: A method and system for determining whether arcing is present in an electrical circuit includes sensing a change in an alternating current in the circuit and developing a corresponding input signal, analyzing the input signal to determine the presence of broadband noise in a predetermined range of frequencies, and producing a corresponding output signal, and processing the input signal and the output signal in a predetermined fashion to determine whether an arcing fault is present in the circuit. The processing includes determining a type of load connected to the electrical circuit, based at least in part upon the input signal and the output signal, and monitoring high frequency noise in a 20 KHz band for each ? cycle of the alternating current.

Abstract: The invention relates to a trip assembly for use in an electro-mechanical device, such as a circuit breaker. The trip assembly is used for interrupting the flow of current upon the detection of excess current in a circuit breaker and comprises a trip bar, a stationary armature bracket, a movable armature, and a spring. The movable armature includes a first end coupled to a base portion of the armature bracket, and a trip-actuating surface being disposed proximate a trip finger of the trip bar. The spring is directly coupled at its respective ends to a spring-support portion of the armature bracket and to a spring tab of the movable armature.

Abstract: A switching mechanism provides sequential switching of first and second circuit breakers to enable switching between a primary power supply and a backup power supply. The switching mechanism comprises a first actuator plate to operate a first circuit breaker connected to a primary power supply, a second actuator plate to operate a second circuit breaker connected to a secondary power supply, and an actuator. The first and second actuator plates are independently movable between on and off positions. The actuator is operatively connected to the first and second actuator plates so that the actuator moves the first actuator plate to an on position and the second actuator plate to an off position when the actuator is moved in a first direction, and moves the first actuator plate to an off position and the second actuator plate to an on position when the actuator is moved in a second direction.

Abstract: A multivariable control system provides regulation for a plurality of control variables of interest based on selecting a particular one of the variables for regulation relative to a corresponding setpoint, while continuing to monitor the other variables and switching regulation control over to another one of the variables as needed to maintain all of them within their allowed ranges. The system includes one or more PID regulators that tune themselves for the particular variables selected for regulation control. In an exemplary embodiment, the control system is configured for controlling an alternative energy system, wherein it includes one or more power flow devices that control power flow between electrical energy storage devices (EESDs) and a common dc bus and/or power flow between the dc bus and an external ac electrical system.

Abstract: An economical digital voltage sag compensator for overcoming sags in distributed electrical power. The voltage sag compensator employs an inexpensive micro-controller, a full wave bridge rectifier, a DC power supply, a voltage divider and an output switch. The micro-controller continuously monitors and evaluates, with respect to a setpoint measured in volt-seconds, the rectified DC voltage. At regularly spaced trigger events, as determined by the micro-controller, the micro-controller concurrently monitors the rectified DC voltage, evaluates the monitored voltage with respect to the setpoint, produces an output signal and sends that output signal to the output switch. The output switch supplies an electrical device, connected electrically in series with the full wave bridge rectifier and the output switch, with a constant average current of sufficient level to maintain the electrical device in a desired operating condition.

Abstract: A microcontroller-based system to detect ground-fault and grounded-neutral conditions in a monitored circuit of an electrical distribution system having line and neutral conductors. The system includes a single sensor producing an output signal responsive to current flow in both the line and neutral conductors of the monitored circuit, and a microcontroller receiving the sensor output signal and initiating the generation of a circuit status signal indicating one of a normal operating condition, a ground-fault condition or a grounded-neutral condition in the monitored circuit. The microcontroller is programmed to continuously test for ground-fault conditions by evaluating the sensor output signal and, at selected intervals, test for grounded-neutral conditions by evaluating the sensor's output signal response to a microcontroller initiated ping in the sensor circuit.

Abstract: A three-phase monitoring system for detecting and dynamically correcting wiring errors in an electrical circuit. The system includes a voltage divider circuit and a current transformer circuit connected to three voltage channels and three current channels, respectively. Samples of the voltages and currents are held in respective sample and hold circuits, which are provided to an analog multiplexer. The analog multiplexer is controlled by a processor, and is coupled to gain and filter circuitry, sample and hold circuitry, and to an analog-to-digital converter (ADC). The ADC is connected to the processor, which analyzes the power factor for a given voltage/current pair. If the power factor is outside of an expected range, the processor dynamically changes the addresses assigned to the channels such that the data arrives in the processor in an expected sequence.

Abstract: A method of determining whether arcing is present in an electrical circuit includes sensing a change in current in the circuit and developing a corresponding input signal, analyzing the input signal to determine the presence of broadband noise in a predetermined range of frequencies, and producing a corresponding output signal, and processing the input signal and the output signal in a predetermined fashion to determine whether an arcing fault is present in the circuit. The processing includes determining a type of load connected to the electrical circuit, based at least in part upon the input signal and the output signal.

Abstract: A monitoring system includes a power source, a power bus coupled to said power source, a plurality of power taps coupled to said power bus, each of said power taps having a ride-through capacitor operatively coupled thereto to provide power during brief interruptions in the power supply to said power bus by said power source.

Abstract: A system for accumulating and evaluating electromagnetic phenomena of at least one power quality category of a power distribution system, using a circuit monitor or processing system that summarizes and trends electromagnetic phenomena. The system provides for expressing the power quality index as a single number for each power quality category present and for combining multiple power quality indices into a single overall power quality index.