Abstract: A power line communications apparatus and method for providing communications over power leads connecting two pieces of electrical equipment. One power lead is split into similarly sized first and second parallel conductors. The first and second conductors pass through a current transformer, the first conductor having a load current flow opposite the second conductor with respect to the current transformer. The transmitted communications signal is applied to the secondary of the current transformer and is induced on the primary of the transformer, namely a loop formed by the first and second conductors. A second current transformer serves as a receiving transducer and senses the communications signal on the first and second conductors.

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 power line communications apparatus and method for providing communications over power leads connecting two pieces of electrical equipment. One power lead is split into similarly sized first and second parallel conductors. The first and second conductors pass through a current transformer, the first conductor having a load current flow opposite the second conductor with respect to the current transformer. The transmitted communications signal is applied to the secondary of the current transformer and is induced on the primary of the transformer, namely a loop formed by the first and second conductors. A second current transformer serves as a receiving transducer and senses the communications signal on the first and second conductors.

Abstract: A system for determining whether arcing is present in an electrical circuit includes a sensor for monitoring a current waveform in the electrical circuit, and an arc fault detection circuit which determines whether an arc fault is present in response to the sensor. The arc fault detection circuit includes a controller which produces a trip signal in response to a determination that an arcing fault is present in the electrical circuit, and an inhibit/blocking function for preventing the production of the trip signal under one or more predetermined conditions.

Abstract: An arc fault circuit interrupter system for use with an electrical circuit includes an arcing fault detector which monitors the electrical circuit and a controller which generates a trip signal in response to the detection of arcing faults. The controller may also generate one or more communication signals corresponding to information relating to the operation of the arcing fault circuit interrupter. The system may also include one or more of the following: a communication port which communicates to a user the information relating to operation of the arc fault circuit interrupter in response to the communication signals; a memory for retaining predetermined information related to the condition and operation of the arcing fault circuit interrupter, with or without a backup memory; and a combined self-test/reset switch.

Abstract: A system for producing a simulated ground fault when arcing is present in an electrical circuit includes a sensor which monitors the electrical circuit. An arcing fault detection circuit determines whether an arcing fault is present in response to the sensor and produces a trip signal in response to a determination that an arcing fault is present in the electrical circuit. A ground fault simulator circuit produces a simulated ground fault in response to the trip signal.

Abstract: A zone arc fault detection system for detecting arcing faults in a defined zone of an electrical circuit, such as an aircraft circuit, includes a pair of substantially identical parallel insulated conductors for each zone in which arcing is to be detected. A detection zone is defined by the parallel conductors between end points where the two conductors are coupled together. A current sensor is operatively associated with each pair of parallel conductors. The current sensor and conductors are respectively configured and arranged such that the current sensor produces a signal representative of a difference in current between the two conductors.

Abstract: An electrical isolation device is provided for use in an electrical distribution network having a plurality of branch circuits each defined by line and neutral conductors connected between a power source and a load, the line conductor being electrically connected to one of a plurality of line buses at an electrical distribution panelboard, the neutral conductor being electrically connected to a neutral bus at the electrical distribution panelboard. The isolation device includes a capacitance coupled between the line and neutral conductor of each of the branch circuits and is designed to provide a low impedance path for an arcing fault occurring on the line conductor of the branch circuit. The capacitance is sufficiently large to provide power factor correcting current.

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: An electrical fault detector system detects electrical 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 a first signal representing the electrical current flow through the monitored circuit and a second signal representing signal components in a selected frequency range typical of arcing faults, and which exceed a predetermined threshold. The system also detects ground faults in the circuit being monitored.

Abstract: A locking nut assembly for use on a shaft having a longitudinally extending channel. The locking nut assembly includes a nut having an annular portion with a slot extending radially through the annular portion. The locking nut assembly also includes a lock plate having an opening therein through which the annular portion of the nut is received and a tab which projects through the slot in the nut and into the channel on the shaft when the assembly is installed on the shaft prohibiting rotation of the nut. A retainer retains the lock plate on the nut.

Abstract: An alternating current sensing apparatus includes at least two coils, each having a plurality of turns of wire around a core which defines a linear axis. The coils are mounted in spaced relation on a support surface so as to define an intermediate space, and the coils are electrically coupled additively in series. The coils produce a detectable signal in response to an alternating electrical current passing through a conductor which extends through the intermediate space.

Abstract: A medium to high voltage load circuit interrupter and method for breaking the flow of electric current in a line having a load and a source. A main switch is connected in series with the line. A metal resistor having a positive temperature coefficient of resistivity (PTC element) is connected in series to the arcing switch, wherein the metal resistor and arcing switch are connected in parallel with the main switch. The main switch moves from the closed position to the open position prior to the arcing switch moving from the closed position to the open position. The circuit interrupter further includes an arc chute having a channel and electrically coupled to the arcing switch wherein the arcing switch is positioned within the channel when the arcing switch is in a closed position. In one embodiment, the PTC element is positioned on an insulator positioned between a ground and the main switch and an arcing switch. In another embodiment, the PTC element is positioned within a channel in the arc chute.

Abstract: A circuit protection apparatus employs a PTC element for overload and/or short circuit protection and an arcing fault interruption arrangement. The circuit protection apparatus may be employed in a ground fault receptacle for interrupting the flow of electrical current in a line in response to any of a plurality of different types of fault conditions on the line. The circuit protection apparatus may include a set of contacts connected in series with the line, and having an open position and a closed position, a trip device coupled to the contacts, adapted to be actuated by a trip signal, to move the contacts from the closed position to the open position and an element having a positive temperature coefficient of resistivity (PTC) connected in series with the contacts. The PTC element is connected to the trip device to provide the trip signal to the device in response to overload or short circuit conditions in the line.

Abstract: A number of methods can be used for zone arc protection to detect series and/or shunt arcing faults in various electrical components and/or circuits. A differential current detector, or a di/dt based detector, may be used to detect shunt arcs, while a differential voltage detector or a zero-sequence voltage detector, is used to detect series arcs. A differential phase current detection scheme may be used for both shunt arcs and series arcs. Series arcs may also be detected using a voltage drop system or a line power loss system. Detection of arcing in joints may be monitored directly. A ground fault detector may be combined with one or more of these systems for detecting a ground fault in the circuit to be protected. Two or more of the above systems or detectors may be combined for arc monitoring and detection.

Abstract: A current sensor has a closed loop magnetic hoop with a gap and a central aperture for receiving a conductor. An IC chip incorporating a Giant MagnetiResistive (GMR) sensor is positioned in the gap to provide a measure of the current in the conductor. A relatively small current transformer provides the necessary information about the direction of the current to an electronic trip unit for a circuit breaker as well as power supply for the IC chip and the trip unit. The trip unit operates in the presence of AC and DC faults. In a three phase power system, a single GMR chip in the proximity of three closely spaced phase conductors, together with a current measurement from the neutral line, enables trip units to operate on the occurrence of AC and DC faults.

Abstract: The present invention provides a compact transformer with a magnetic core having at least two leg members and two side members. Each leg member has two ends and a peripheral surface therebetween. Each side member has a generally planar body with at least two notches corresponding in cross-sectional shape and size to the end of each leg member. The sides of each notch surround and abut a majority of the peripheral surface near each leg member end. The leg member end is secured to each notch. A magnetically coupled primary and secondary winding is arranged around each leg member. The transformer is particularly useful in sending current signals to an electronic trip unit of a circuit interrupter.

Abstract: An improved miniature circuit breaker is provided which is adapted to improved automatic assembly of all components thereof. Key components of the breaker are individually and collectively designed to be susceptible to total Z-axis assembly. In particular, the circuit breaker operating mechanism which operates the contacts thereof to make or break the electric circuit is formed of elements designed to interact in a Z-axis assemblable fashion. The movable contact is defined on a contact carrier or blade assembly which is adapted for Z-axis assembly and also provides increased arc erosion resistance and improved opening of the breaker contacts.

Abstract: A bimetallic thermal release element (34) for use in a thermally actuated tripping mechanism, and in particular used in electrical circuit breakers (10) wherein the load current is passed through the bimetallic element has a self-aligning floating latch member (141) configured to engage the release member and to disengage therefrom when the bimetallic element bows a sufficient amount at a given temperature or current. The bimetallic element is preferably an elongated member supported at its ends (128, 130) by side members (28, 42). An increased sensitivity is imparted to the bimetallic element by mounting the side members for rotation to accommodate the bowing.

Abstract: A current interrupter in which a first movable, insulating, gear carries a contact blade. The blade extends out from this movable gear and forms a contact which makes and breaks with a stationary contact upon movement of the gear. A second insulating gear has a set of teeth which engage the teeth on the first gear. The second gear has a cavity into which the extended contact fits. Movement of the first gear in a direction to break the contact, causes the engaged teeth to drive the extended contact into the cavity, thereby insulating the movable contact from the stationary contact. The interlocking gear teeth create a tortuous path for the arc and provide a large over surface distance for dielectric strength.