Abstract: The present invention is directed electrical wiring protection device that includes a housing assembly having line terminals, load terminals, and receptacle terminals. A fault detection circuit is configured to generate a fault detection signal in response to detecting fault conditions. First interrupting contacts are configured to electrically couple the line terminals and the load terminals in a reset condition and decouple the line terminals from the load terminals in response to the fault detection signal in a tripped state. A wiring state detection circuit is coupled to at least one of the line terminals. The wiring state detection circuit is configured to generate a first wiring signal when the line terminals are connected to a source of AC power. Second interrupting contacts are configured to electrically couple the at least one receptacle load terminal to the at least one load terminal in response to the first wiring signal.

Abstract: The present invention is directed to a protective device that includes a plurality of line terminals and a plurality of load terminals. A wiring state detection circuit is configured to detect a wiring state associated with the plurality of line terminals and the plurality of load terminals. A fault detection circuit is coupled to the plurality of line terminals and configured to generate a fault detection signal in response to detecting at least one fault condition. A circuit interrupter is coupled to the fault detection circuit. The circuit interrupter includes four sets of interrupting contacts configured to provide electrical continuity at least between the hot line terminal and the hot load terminal and the neutral line terminal and the neutral load terminal in a reset state. The four sets of interrupting contacts are open in a tripped state.

Abstract: The present invention is directed to an electrical wiring protection device that includes a housing assembly having at least one line terminal and at least one load terminal partially disposed therein. A first conductive path is electrically coupled to the at least one line terminal. A second conductive path is electrically coupled to the at least one load terminal, the second conductive path being connected to the first conductive path in a reset state. A fault detection circuit is coupled to the first conductive path. The fault detection circuit is configured to generate a fault detection signal in response to detecting at least one fault condition. A wiring state detection circuit is coupled to the first conductive path. The wiring state detection circuit selectively provides a wiring state detection signal when the at least one line terminal is coupled to a source of AC power, and not providing the wiring state detection signal otherwise.

Abstract: The present invention is directed to a protection device that includes line terminals coupled to a power source disposed in an electric power distribution system. The protection device is configured to protect a portion of the power distribution system from at least one fault condition. The device includes a receptacle member that includes a housing and a cover. The cover includes receptacle openings configured to accommodate plug contact blades. Receptacle contacts are disposed in the housing. The receptacle contacts are also coupled to the line terminals to thereby establish an electrical connection between the receptacle contacts and the line terminals. Each receptacle contact is in communication with a corresponding receptacle opening. A protective shutter mechanism is integrated into the housing. The protective shutter mechanism is movable from a closed position to an open position upon insertion of the plug contact blades.

Abstract: The present invention is directed to a protective device that includes a plurality of line terminals configured to be connected to an electrical distribution system, and a plurality of load terminals configured to be connected to at least one load. The device includes a fault detection circuit coupled to the plurality of line terminals and the plurality of load terminals. The fault detection circuit is configured to detect at least one fault condition. A power interruption circuit coupled to the fault detection circuit, the power interruption circuit including a set of movable contacts configured to decouple the plurality of line terminals from the plurality of load terminals in response to the fault detection circuit detecting the at least one fault condition. A reset mechanism is coupled to the power interruption circuit and configured to actuate the movable contacts to re-couple the plurality of line terminals to the plurality of load terminals. A lock-out mechanism is coupled to the reset mechanism.

Abstract: A noise reduction system is connected to at least two input channels for receiving input signals that have substantially identical program content but differing instantaneous noise transients. The system selects a filtered input signal that has the lowest instantaneous noise transient level. In another aspect, the noise reduction system removes instantaneous transient noise from an input signal by way of a blanker. The blanker includes a switch that opens whenever a band-pass filtered input signal is greater than the average level of the signal by a predetermined proportional amount. The input signal also includes continuous noise that is removed by a continuous noise suppressor. The continuous noise is removed by a low pass filter whose corner frequency is responsive to a differentiated input signal divided by the program component signal, or vice versa.

Abstract: An arc fault circuit interrupter (AFCI) detects arc faults by identifying the various signature patterns of arc fault noise while rejecting arc mimicking noise from normal load phenomena.

Abstract: Briefly stated, and in accordance with a presently preferred embodiment of the invention, an arc fault detecting circuit using, a pulse width modulation, or PWM, technique is used to sense series or parallel arc faults. When arc faults occur, typically an arc step in current is followed by broad band arc noise which is caused by the random fluctuations in arc column resistance. In this invention, a logic signal is created which has a duration or width that corresponds to the time interval during which the broad band arc noise generated by the arc is present. Typically an arc fault randomly starts, generates broad band arc noise, and then extinguishes as the next current zero cross of the AC load current is approached. The random start causes PWM of the logic pulse whenever the start of the arc randomly moves with respect to the current zero cross. An arc fault that randomly starts, and then randomly stops, will also cause PWM with respect to the zero cross.

Abstract: An AC power line protection device includes a resistive element connected at one end to a hot power conductor and at another end to either a breaker coil operatively associated with a set of interrupting contacts or to a gate or base for a switch element. When AC power is miswired to the load terminals, the device trips the contacts due to the presence of the resistive element. The device does not work properly until AC power is connected to the line terminals, at which time the resistive element clears itself from the circuit. An indicator lamp lights when the device is in the tripped condition and turns off when the device is reset. If the device is miswired after having been wired properly, i.e., the resistive element has cleared, the indicator lamp does not light when the device is tripped, and so provides a supplemental indication of miswiring.

Abstract: Downstream series and parallel arcing in AC power lines is determined by using a detector and microprocessor to detect characteristic di/dt behavior received from a current sensor through which the power lines pass. When downstream parallel arcing is detected, the microprocessor uses a speedy algorithm which cannot be used to detect series arcing. Upstream series arcing is detected by sensing a flat voltage portion of the line voltage. Upstream parallel arcing is detected by sensing a voltage spike followed by a voltage flat portion of the line voltage. When upstream parallel arcing is detected, the microprocessor is temporarily shut off to avoid false tripping.

Abstract: A thermal protective fuse having a cylindrical body with a thermally protective portion disposed substantially adjacent to one end of the cylindrical body is mounted in close proximity with the body of a metal oxide varistor, with the thermally responsive portion of the fuse positioned approximately adjacent the center of the varistor body.

Abstract: A self-testing arc fault or ground fault detector includes arc fault detecting circuitry and components. The detector includes a testing circuit which tests at least part of the circuitry and components and generates a recurring signal when the test completes successfully. If the test does not complete successfully, the signal is lost. This loss of signal is signaled by an indicator connected to the testing circuit. In one version, the loss of signal activates a circuit interrupter which disconnects the load side of the detector from the line side.

Abstract: An arc fault detector for detecting an arc fault in electric power lines includes a two stage arc sensor. The first stage is a current transformer designed for high sensitivity to arc faults but which may saturate and lose detection capability during arc currents at 75A and higher. The second arc fault sensor, which does not saturate, stage senses the voltage across the impedance of the primary of the current transformer, or senses the voltage across the resistance of a section of the load carrying bus which forms the connection through the detector device, or of both, during an arc fault.

Abstract: An arc fault detector for detecting electric power lines includes a sensor for sensing the derivative of the current on the electric power line, a converter circuit for converting the derivative of the line current into first and second signals, the first signal responsive to positive step transitions of arc fault current, and the second signal responsive to negative step transitions of arc current, and a temporal detector for signaling the presence of an arc fault when one of the first and second signals follows the other within a predetermined time, or window, and in which a sequence of one of the signals following the other signal occurs in a second predetermined interval of time.

Abstract: An arc fault detecting circuit using a pulse width modulation, or PWM, technique is used to sense series or parallel arc faults. When arc faults occur, typically an arc step in current is followed by broad band arc noise which is caused by the random fluctuations in arc column resistance. In this invention, a logic signal is created which has a duration or width that corresponds to the time interval during which the broad band arc noise generated by the arc is present. Typically an arc fault randomly starts, generates broad band arc noise, and then extinguishes as the next current zero cross of the AC load current is approached. The random start causes PWM of the logic pulse whenever the start of the arc randomly moves with respect to the current zero cross. An arc fault that randomly starts, and then randomly stops, will also cause PWM with respect to the zero cross.

Abstract: Briefly stated, and in accordance with a presently preferred embodiment of the invention, an arc fault detecting circuit using, a pulse width modulation, or PWM, technique is used to sense series or parallel arc faults. When arc faults occur, typically an arc step in current is followed by broad band arc noise which is caused by the random fluctuations in arc column resistance. In this invention, a logic signal is created which has a duration or width that corresponds to the time interval during which the broad band arc noise generated by the arc is present. Typically an arc fault randomly starts, generates broad band arc noise, and then extinguishes as the next current zero cross of the AC load current is approached. The random start causes PWM of the logic pulse whenever the start of the arc randomly moves with respect to the current zero cross. An arc fault that randomly starts, and then randomly stops, will also cause PWM with respect to the zero cross.

Abstract: Briefly stated, and in accordance with a presently preferred embodiment of the invention, an arc fault detecting circuit using a pulse width modulation, or PWM, technique is used to sense series or parallel arc faults. When arc faults occur, typically an arc step in current is followed by broad band arc noise which is caused by the random fluctuations in arc column resistance. In this invention, a logic signal is created which has a duration or width that corresponds to the time interval during which the broad band arc noise generated by the arc is present. Typically an arc fault randomly starts, generates broad band arc noise, and then extinguishes as the next current zero cross of the AC load current is approached. The random start causes PWM of the logic pulse whenever the start of the arc randomly moves with respect to the current zero cross. An arc fault that randomly starts, and then randomly stops, will also cause PWM with respect to the zero cross.

Abstract: An arc fault circuit interrupter (AFCI) detects arc faults by identifying the various signature patterns of arc fault noise while rejecting arc mimicking noise from normal load phenomena.

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

Abstract: A gfi wiring device is disclosed in the form of a duplex receptacle for receiving the blades of a plug connecting an electrical appliance or other load to the circuit wherein the gfi device is connected. The housing sections and components of the gfi are so configured and relatively arranged that the device may be automatically assembled by downward, vertical movement of the components and the front housing section in a predetermined sequence relative to the rear housing section as the latter is positioned on a horizontal support. The device is operationally tested after assembly is complete and, upon successful testing, the housing sections are permanently connected by heat deformation of portions of one section to form a rivet-like connection. Reliability of testing is improved by breaking the usual traces on a printed circuit board extending between terminals to which jumper cables are connected to provide a fail-safe indication of circuit continuity through the jumper cables.