Abstract: Disclosed herein is a sensor assembly (10) for attachment to an electrical conductor (5), which includes a base (20) having a cavity (22) and a pair of detector housings (30) extending from the base (20). The detector housings (30) are laterally spaced and substantially parallel and are provided to receive a magnetic field detector. An electronic circuit card (70) is disposed within the base cavity (22) and is operatively coupled to the magnetic field detectors. Additionally, an auxiliary circuit card (90)) that contains logic for detecting an arc fault may be provided for communicating with the electronic circuit card (70).

Abstract: Electrical equipment (14) is safeguarded from damage due to parallel arc faults by a circuit that provides several levels of protection. A semiconductor switch (18) and a current sensor (24) are placed in series with the electrical equipment (14). When the current to the equipment exceeds a first threshold for a predefined period of time, the semiconductor switch (18) 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 (18) in conductive and non-conductive states so that the average current applied to the equipment (14) is within an acceptable level. The pulses are measured to determine whether a parallel arc fault has occurred. When the measured pulses (74) are within a predetermined range, a parallel arc fault is declared and the semiconductor switch (18) is rendered non-conductive.

Abstract: A varying voltage is applied across a coil of a contactor. The varying voltage has a characteristic (frequency) which varies as a function of the position of the armature. The varying voltage is transmitted to a coupler which transmits information to a controller. The coupler may include one or more light sources (LEDs) which are sequentially energized and de-energized to sequentially render a phototransistor conducting and nonconducting. The frequency of the output from the coupler corresponds to the frequency at which the phototransistor is changed between the conducting and nonconducting conditions. A controller determines whether the frequency of the output from the coupler corresponds to the intended position of the armature of the contactor or to an unintended position by comparing the frequency of the output from the coupler to known frequencies for various positions of the armature.

Abstract: An improved electromagnetic apparatus includes a core and an armature which is movable relative to the core. A shading ring is connected with the core to provide magnetic flux which is out of phase with magnetic flux from the core. The shading ring includes a base formed a first metal and a layer of a second metal clad to the base. The first metal forming the base work hardens and has a greater resistance to fatigue failure induced by vibration than the second metal of the layer which is clad to the base. However, the second metal forming the clad layer has a greater electrical conductivity than the first metal of the base. The base may be formed of aluminum and the layer of metal clad to the base may be formed of copper. The layer of copper may be clad to the base by an extrusion process.

Abstract: A contactor has an armature, a pull-in coil and a holding coil. When the system is energized through a first switch such as a thermostat, the low current holding coil is energized in preparation for holding the armature pulled in after the pull-in coil is energized and the armature has finished its power stroke. A solid-state switching device and the pull-in coil are connected in series between both terminals of a power source. A control circuit causes the solid-state switching device to be conductive the instant power is supplied to the circuit through the first switch. One embodiment of the control circuit is based on logic gates. RC circuits associated with the gates keep the solid-state switching device and pull-in coil conducting long enough for the armature to pull-in. After the solid-state switching device turns on, the transistor is controlled to turn off, deenergizing the pull-in coil while the holding coil holds the armature in until the first switch opens and power input is discontinued.

Abstract: A current transformer device is formed on a ceramic substrate which is provided with a plurality of planar conductive tracks formed on a surface of the substrate where the conductive tracks extend substantially radially from an imaginary point on the surface of the substrate. A structure of permeable material layers is then tape cast or epitaxially formed by vapor deposition of a thick film of magnetic ceramic over the major portion of each of the conductive tracks to form a permeable toroidal core. A lead frame is then placed over the core and a plurality of metal conductors are soldered to each of the respective exposed ends of the metal conductive tracks on the substrate to form a toroidal coil surrounding the toroidal core. The required electrical elements to complete the current transformer device are mounted to a second side of the ceramic substrate and electrically connected to the toroidal coil for powering and/or receiving signals therefrom.

Abstract: A current transformer device is formed on a ceramic substrate which is provided with a plurality of planar conductive tracks formed on a surface of the substrate where the conductive tracks extend substantially radially from an imaginary point on the surface of the substrate. A structure of permeable material is then tape cast or epitaxially formed by vapor deposition of a thick film of magnetic ceramic over the major portion of each of the conductive tracks to form a permeable toroidal core. A lead frame is then placed over the core and a plurality of metal conductors are soldered to each of the respective exposed ends of the metal conductive tracks on the substrate. The required electrical elements to complete the current transformer device are mounted to a second side of the ceramic substrate and electrically connected to the toroidal coil for powering and/or receiving signals therefrom.

Abstract: An electrical power switching device employing a rotary disc driven by an actuation means whose position is selected by a control means where disc contacts engage and disengage stationary contacts where the stationary contacts are deflected away from the disc contacts by separation ramps thereby opening the current path and an arc plate is used on the disc to control arc energy. A pair of interrupter contacts are placed in series with the rotary disc contacts where abnormally high currents cause the interrupter contacts to separate and open the current path where slot motors and/or arc plates are used to dissipate the damaging electrical arcs as the contacts make and break.

Abstract: A bypass contactor usable in a solid state motor starter for shunting current around a fully-conducting solid state switching device comprising an electromagnetic contactor housed in a molded insulating enclosure having a plurality of bridging contacts movable into and out of engagement with a pair of stationary contacts to provide plural parallel current paths within the contactor, the stationary contacts having rigid terminal portions projecting externally of the insulating enclosure connectable to the heat sinks of the solid state motor starter in a preferred manner to suspend the contactor above the panel, permitting other components to be mounted below the bypass contacts. Alternate embodiments have the contactor mounted to the same support as the starter power pole component assembly and electrically connected thereto by rigid preformed connectors or flexible braided straps.

Abstract: An electrical contractor device (80) for controlling the flow of electrical power from a source of electrical power to an electrical device according to a command signal from a controller utilizing a rotary disc assembly (90) rotated by an actuator (169) where the rotary disc assembly (90) is comprised of a rotary disc (100) supporting a disc conductor (102) having a pair of contact pads (106, 108) joined by a pair of conductor legs (109, 113) and a center section (111) where the conductor legs (109, 113) are parallel and offset one from the other straddling an axis of rotation (103) where high flow of electrical current through the disc conductor (102) generates an electro-magnetic torque in the rotary disc assembly (90).

Abstract: An arc detector antenna transducer (62) for an electric circuit has an electrified conductor (46) connecting a voltage source (26) to a load (30). The arc detector transducer includes an E field sensor (66) sensing the E field established about the conductor by the occurrence of an electrical arc in the circuit, and a B field sensor (68) sensing the B field established about the conductor by the occurrence of the electrical arc in the circuit.

Abstract: An arc detection method and apparatus is provided for an electric circuit having an electrified conductor (46) connecting a voltage source (26) to a load (30). The system senses the electromagnetic field established about the conductor by the occurrence of an electrical arc in the electric circuit, and generates a field responsive signal. Arc discrimination circuitry responding to the field responsive signal and generates an arc indicative signal in response to a given characteristic of the field responsive signal. The system includes an E field sensor (66) and a B field sensor (68).

Abstract: A pressure sensitive pad assembly for a brake pedal having in one embodiment a pair of plastic films with metallized surfaces spaced apart by apertured spaces and embedded in an elastomeric pad to be placed on a brake pedal. Application of a brake actuating force on the pad causes the elastomer to deform closing contact between the metallized surfaces for actuating a brake light. In another embodiment a pressure sensitive transducer pad assembly has embedded in elastomeric material, a plurality of piezoelectric strips which are deformed, upon application of a brake actuating force to the pad, for providing an electrical signal indicative of the magnitude of the brake actuating force. In another embodiment an elastomeric pad spans a shallow recess in a support with piezoelectric material provided on the spanning surface and deformation of the pad into the recess deforms the piezoelectric material to provide a brake actuating force signal.

Abstract: The present invention is a current sensor employing a magneto resistive sensor having high fidelity of output. This current sensor includes a magnetic flux concentrator substantially encircling the electrical conductor having magnetic sensing, a magnetic device generating a magnetic field component along an axis offset from the principle axis, a magneto resistive device disposed in the magnetic sensing region, a constant current source supplying a predetermined constant current to said magneto resistive device, and a voltage sensing circuit connected to said magneto resistive device for measuring resistance by measuring a difference voltage induced by said constant current. This measured voltage corresponds to the current through the conductor. The magneto resistive device is formed as a Wheatstone bridge having a first and second pair of opposite terminals.

Abstract: The present invention is a proximity sensor employing a magneto resistive structure. This proximity sensor includes a toroidal magnet having a central aperture, an inner circumference and an outer circumference. This toroidal magnet has a first magnetic pole at the inner circumference and a second magnetic pole at the outer circumference thereby creating a magnetic field null at a center portion of the central aperture. A magneto resistive structure is disposed at the magnetic field null in the central aperture of the toroidal magnetic. This magneto resistive structure has a resistance dependent upon magnetic flux. The proximity of a magnetically permeable target to the toroidal magnet shifts the position of the magnetic null, thereby causing a large change in the magnetic flux through the magneto resistive structure. An electrical detection circuit detects changes in this resistance for indication of the proximity of the magnetically permeable target.

Abstract: A current sensor (10) comprising spaced pole pieces (62, 64) and a magnetic shunt (80) bridging the pole pieces within an insulating housing assembly (12) which also contains a magnetoresistive transducer (90) and electronic circuitry (16) for sensing magnetic field intensity between the pole pieces and relating that intensity as electric signals provided at terminals (26) at the exterior of the housing. The transducer senses magnetic field intensity along a principal axis (88). Permanent magnets (94, 96) or induction coils (276, 278) are provided to establish a biasing component of magnetic field intensity along an axis (98) substantially normal to the principal axis to improve sensor sensitivity, range of operation and immunity to current overload.

Abstract: A magnetic flux concentrator comprising spaced pole pieces (4,6) and magnetic shunt (8) bridging the pole pieces within an insulating housing (2) which also contains a magnetoresistive transducer (24) and electronic circuitry (26) for sensing magnetic field intensity between the pole pieces and relating that intensity as electric signals provided at wiring terminals (28) at the exterior of the housing. The pole pieces have magnetic terminal portions adjacent openings in the housing for removable attachment thereto of selected ferrous strap configurations (42,50,52,60) determined by the cross-sectional shape of the electrical conductor (46) in which current flow is to be measured, the respective strap configuration and flux concentrator forming a magnetic loop around the conductor for picking up the magnetic flux induced by current flow in the conductor.

Abstract: An electromagnetically actuated hydraulic switch unit is provided by an armature plunger which reciprocally shuttles between partially overlapping magnetic paths and operating a hydraulic valve circuit through bistable snap blade means. Snap blades open and close entry ports, exit ports and vent ports to connect various passages in a housing and perform given hydraulic functions. The ratio of the permeances of the two magnetic paths, created by dedicated coaxial coils, is controlled such that one path always overpowers the other by an amount greater than the mechanical gradients of a pair of snap blades in hydraulic fluid filled cavities, to insure plunger movement in either direction.

Abstract: A pair of heaters (16,18) are mounted within a breaker housing (2) in spaced relation to a temperature responsive actuator element (30) for indirectly heating that element in response to current flow in the heaters. Each heater is provided with a wiring terminal member (6,8) for selectively individually connecting one or the other heater in circuit with a branch circuit to be protected. One heater (16) is selected to generate greater amounts of heat than the other heater (18) when subjected to the same current levels.

Abstract: A heater strip (12) is disposed in spaced relation to a temperature responsive actuator element (20) for indirectly heating that element in response to current flow in the heater (12). An adjustable heat sink (22) is disposed in spaced proximity to the actuator element (20) for removing heat from the actuator element by radiation therefrom through air to the heat sink in a first position and adjustable to be in thermally conductive engagement with the actuator in a second position for increasing the efficiency of heat transfer from the actuator to the heat sink. Increased current flow in the protected branch circuit is required to cause the actuator (20) to attain its predetermined actuation temperature as the heat sink is adjusted to increase the efficiency of heat transfer between the actuator (20) and the heat sink.