Abstract: The present invention is an isothermal current shunt device with excellent temperature coefficient of resistivity characteristics stability for use in a power measuring circuit having a wide temperature and dynamic range and particularly for customers of electric utility companies, and it includes a first arm having a first flange portion, a second arm having a second flange portion, and a bridge means coupling the first arm to the second arm wherein the bridge means is a monolithic sintered powdered-metal piece having a block portion and a loop portion. The block portion has a first face juxtaposed to and electrically coupled to the first flange portion of the first arm and a second opposing face juxtaposed to and electrically coupled to the second flange portion of the second arm. This configuration allows a majority of electrical current to conduct between the first arm and the second arm.

Abstract: An apparatus and method is provided for dividing a voltage with a resistor voltage divider and for employing the voltage divider in an integrated circuit. The resistor voltage divider utilizes inaccessible compensation taps that are placed between nonlinearly spaced output taps. The compensation taps reduce the impact of tap resistance on the voltage divider transfer function. The number of inaccessible compensation taps placed between output taps is dependant upon a chosen tap density that is substantially maintained across the body of the resistor voltage divider. The resistor may be used in integrated circuits employing amplifiers, such as volume control circuitry.

Abstract: An electrical test shunt having a pair of female contacts each having two contact points for relocating voltage sensing points of a test shunt to provide a first circuit path with an adequate current flow that is independent of a second circuit path for reading the voltage drop across the same electrical test shunt. The voltage is read by a high input impedance voltage comparator. The input impedance of the voltage comparator is great enough to negate the affect of the internal resistance inherent in the mating terminals of the shunt. The two circuit paths are made possible in part by the implementation of a pair of terminals which each have two independent electrical contact areas. The terminal contact is typically inserted into the female receptacle formed by the two separate (i.e. electrically isolated) electrically conducting contact points. The female terminal is preferably mounted in a suitable printed circuit board.

Abstract: A junction box incorporating an integrally formed shunt busbar. The shunt busbar incorporates a first pair of terminals to act as leads to couple the shunt busbar in a current loop of a circuit, and a second pair of terminals to couple a voltage sensing device across a portion of the shunt busbar. The voltage sensing device is preferably a high input impedance voltage comparator. The input impedance of the voltage comparator is great enough to negate the affect of the internal resistance of the mating terminals of the busbar. Furthermore, the second pair of terminals is located on the shunt busbar such that the terminal resistances thereof are outside of the current loop. The electrical busbar is preferably mounted in a suitable insulating housing. When the shunt busbar of the present invention is connected to the high input impedance voltage comparator, a circuit path that allows for easily and accurately measuring the voltage drop across the busbar is made possible.

Abstract: A shunt resistor for use with current sensing and power hybrid circuits such as a solid state power controller which is adapted to conduct the full load current and serve as a current sensor comprises a base layer of aluminum electrically isolated from and thermally coupled to a circuit layer of monel 401 through a ceramic filled polymer layer. The shunt is provided with spaced wire bond portions for attachment to circuit traces of the controller.

Abstract: An isothermal current shunt device with excellent temperature coefficient of resistivity characteristics stability for use in a power measuring circuit having a wide temperature and dynamic range and particularly for customers of electric utility companies, and it includes a first arm having a first flange portion, a second arm having a second flange portion, and a bridge means coupling the first arm to the second arm wherein the bridge means is a monolithic sintered powdered-metal piece having a block portion and a loop portion. The block portion has a first face juxtaposed to and electrically coupled to the first flange portion of the first arm and a second opposing face juxtaposed to and electrically coupled to the second flange portion of the second arm. This configuration allows a majority of electrical current to conduct between the first arm and the second arm. The loop portion is outside the first face and the second face of the block portion and conducts a minority of current.

Abstract: A current shunt for converting a current to a voltage. The current shunt of the invention is made from a conductive material such as a high performance resistance alloy in sheet form which is sheared, punched, and bent to produce a highly stable current shunt with respect to time and temperature. Contact pins of current and potential connections are welded to the material using a fusion welding process, and techniques are also provided for isolating the potential contacts from the current contacts so as to improve stability. Trimming slits of the type used for thin film or foil resistors are also extended to bulk materials in accordance with the invention such that highly accurate resistances may be obtained. An integral heat sink and strain relief mechanism is also provided so as to minimize the adverse effects of temperature on the resistance of the material. The resulting current shunt has an extremely stable resistance value with respect to time and temperature at a minimal cost.

Abstract: A measuring sensor of an electronic trip device of a circuit breaker comprises a shunt in the form of a hollow cylinder inside which there is located an electronic processing unit, comprising an amplifier circuit and an input resistance in good thermal contact with the internal face of the cylinder.

Abstract: A current shunt device has main and auxiliary windings which are located in substantially the same position and are connected in series.

Abstract: A differential electrical current shunt which is particularly adapted for the measurement of large currents with high accuracy and substantially free of errors due to ageing, connection resistance and differentials therein and thermally induced resistance changes. The shunt, according to the invention divides the large current into two substantially equal portions by forming a preferably elongated aperture in a conductor carrying the large current; the two portions of the conductor formed by the aperture having substantially equal but slightly differing resistances. The two conductor portions are formed with respect to a core such that the conductor portions each form a single turn coil on the core with the induced flux from each conductor portion opposing that included in the coil by the other of the two conductor portions.

Abstract: A film resistor for use in electrical circuits, the resistor including a shunt conductor electrically connected in parallel with a portion of the resistive film, at a location spaced apart from the principal circuit conductor terminals of the resistor. The resistor is made with an intentionally low initial resistance, and is trimmed to a predetermined resistance by removal of a portion of the resistive material between the circuit conductor terminals. A plunge cut made in the resistive material by a trimmer and extending toward the shunt conductor can be used to provide a wide range of change of resistance without excessive increase of the rate of change of resistance as a function of extension of the plunge cut.

Abstract: A multipurpose electrical shunt, formed from an integral body of material, includes a first and second electrical connectors spaced apart for mating with a first terminal of a main circuit breaker and a first terminal of a branch circuit breaker. The shunt further includes an electrically resistive material integrally connected to the first and second electrical connectors for providing a voltage drop thereacross proportional to the current flowing therethrough and first and second output terminals extending beyond the resistive material for connection to a current sensing means such as an electrical meter. The shunt provides a current carrying conductor connecting a main circuit breaker to the branch circuit breaker and further provides sensing of the current flow between the main circuit breaker and the branch circuit breaker.

Abstract: Various combinations of three elements are disclosed for use in accurate measurement of power through current measurement over a wide dynamic range, namely, a current shunt which is preferably an isothermal current shunt, a current transformer, which is preferably a high initial permeability current transformer, and a low-impedance burden load, which in the preferred embodiment includes an active negative impedance element which causes the removal of the effects of excitation current by canceling secondary winding resistance of the current transformer. In a specific embodiment of an isothermal current shunt according to the invention, a very linear device is achieved by construction out of copper in such a manner that the poor resistance versus temperature coefficient of copper does not affect the accuracy of measurement. Specifically, the shunt is constructed in an unbalanced isothermal bridge configuration, so that heat-induced variations are suppressed.

Abstract: In order to minimize the effect of return current flow on a current measuring shunt, the present invention proposes a shunt having a compensation circuit to compensate for the asymmetrical effect of such return currents. Such compensation is provided by two measuring circuits which are to measure the voltage drop across the shunt, and each circuit is located in a median plane of the shunt. The path of each of these measuring circuits is optimized and established in the calibrated configuration of the shunt. These parallel measuring circuits also have their inputs and outputs connected together respectively. Particularly, the present invention relates to shunts having a tubular or rectangular configuration and including such compensation circuits.

Abstract: A transducer for current measurements includes a flat conductor with at least two main current branches for the current to be measured and at least a cross-branch current bridge connecting two locations of differing potential of the two main current branches. A magnetic core is laid around one of the branch current paths. The flat conductor is formed such that it is provided in its cross-direction with a bending edge for redirecting current and each main current branch or part thereof at least approximately coincides with and is of an opposite current direction to a main current branch or part thereof of the other leg.

Abstract: In order to reduce errors between the measured current by a rectangular shunt and the shunt output signal voltage, such errors being due primarily to skin effect and the proximity of the shunt to the current circuit to be measured, the present invention proposes a shunt having a measuring system which compensates for these error causing effects. The shunt utilizes a measurement circuit following a path which reduces the difference between the potential produced across the shunt and the form of a current which passes therethrough. The path of the measuring circuits starts from the center of the resistive material of the shunt and progresses towards the outer surface of the resistive material in accordance with a function which is non-monotonic and which can even follow a curved path. More particularly, the shunt has a rectangular geometry to permit the maximum heat dissipation which is produced by the shunt in its continuous operating mode under ambient conditions.

Abstract: An apparatus for sensing and measuring a DC or AC current on an LV or HV power circuit. The apparatus comprises a shunt element having an input connected to the transmission line. The current flowing through the shunt is measured by an electronic circuit which is located in a conductive housing connected in series with the shunt element. The housing conducts the current from the shunt back to the power circuit. The housing is dimensioned to contain therein the electronic circuit whereby to shield the circuit from thermal effects of the shunt element, the magnetic field effect of the measured current, and environmental electrostatic interference.

Abstract: The present invention relates to a current divider for a measuring transducer. The current divider includes two conductors. The first conductor, which is operable as a shunt, comprises two generally flat legs which extend parallel to one another. Each leg defines one aperture into which the core of the measuring transducer extends. The second conductor is z-shaped having two arms and a bridge extending between the two arms. The arms are electrically connected to one of the legs and the bridge crosses the aperture therein, so that the bridge is surrounded by the core.

Abstract: An apparatus relating to a voltage divider having one or more Kelvin connection taps, including first and second spaced terminals and a current carrying resistor between the first and second terminals. A third terminal is spaced from the resistor and the resistor has at least one conductive but non-current-carrying peninsula extending from a junction on the side of the resistor and connecting with the third terminal to produce a Kelvin connection tap. A cut is made only in the non-current-carrying peninsula along the path having a component parallel to the side of the resistor from which the peninsula extends and shading the junction of said peninsula and the side from the third terminal, to adjust the interconnection of the third terminal with the resistor and vary the voltage output without varying the resistance of the resistor. An extension of this cut may be made parallel to the edge of the peninsula to further increase the adjustment.

Abstract: A current divider for use in connection with a measurement transducer. The measurement transducer includes a magnetic core, is formed as a substantially flat and longitudinal conductor with two longitudinal slits so as to partition the flat conductor into at least a measurement conductor, and at least two shunts are connected in parallel with the measurement conductor. The shunts define a plane, and the measurement conductor is disposed in the plane between the shunts. The flat conductor has two openings along the longitudinal direction, to receive the magnetic core. One slit communicates with one opening, and the other slit communicates with the other opening.

Abstract: A measurement shunt comprises a resistance provided with first and second voltage terminals and intended to provide a voltage representative of an electric current passing through it, and an inductance connected to at least the first of said voltage terminals to produce between first and second measurement terminals a voltage free of error voltages induced in said resistance, even in the presence of a variable magnetic field. The resistance is essentially constituted by a plate (12) of electrically conductive material, the first and second voltage terminals (26,28) are disposed on the same edge of the plate at spaced apart points thereon, and the inductance comprises at least one open loop (36a) at least partly formed from an electrically conductive material extending from its first and second ends respectively disposed in the vicinity of the first and second voltage terminals, towards the interior of the surface of the plate in a plane having, at least approximately the same direction as the plate.

Abstract: A current sensing device includes an electrically conductive current shunt member (10), and a voltage-responsive member (12). The current shunt member includes a first portion (14) having a free end (20), and a second arcuate portion (16) including an arcuate slot (38) defined by a constant radius (45) centered about the free end (20) of the first section, so that when current is passed through the arcuate section (16), the voltage produced by the shunt (10) may be varied by pivoting the voltage-responsive member (12) retained at the free end (20) of the first member and at the arcuate slot (38), and bridging or spanning between this first free end (20) and the arcuate slot (38). Preferably, the current-sensing member (12) includes electrical or electronic circuitry, for providing an output when sensed voltage, proportional to current through the arcuate portion, exceeds a predetermined level.

Abstract: An apparatus relating to a voltage divider having one or more Kelvin connection taps, including first and second spaced terminals and a current carrying resistor between the first and second terminals. A third terminal is spaced from the resistor and the resistor has at least one conductive but non-current-carrying peninsula extending from a junction on the side of the resistor and connecting with the third terminal to produce a Kelvin connection tap. A cut is made only in the non-current-carrying peninsula along the path having a component parallel to the side of the resistor from which the peninsula extends and shading the junction of said peninsula and the side from the third terminal, to adjust the interconnection of the third terminal with the resistor and vary the voltage output without varying the resistance of the resistor. An extension of this cut may be made parallel to the edge of the peninsula to further increase the adjustment.

Abstract: A current divider having two major current paths and a shunting current path is disclosed. The shunting current path connects the two major current paths at a point on each major current path such that the shunting current path connects points which have slightly different voltage potentials. This slight difference in voltage potentials causes a current to flow in the shunting current path. The current that flows in the shunting current path is a predetermined fraction of the total current and is primarily dependent on the difference in voltage potentials which is a function of the location of the shunting current path. The current that flows in the shunting current path is substantially independent of the ratio of the cross-sectional areas and/or the inverse lengths of the current paths in that for a given cross-sectional area of the shunting current path various values for the current split off may be obtained by varying the location of the shunting current path.

Abstract: A fuser includes a pair of members defining a zone, a pair of electrical elements supported in series with a power supply by one of the members, and a thermostatic switch being electrically connected in parallel with one of the elements. When the temperature in the zone is below a predetermined level the switch is closed and shorts out the element with which it is in parallel. The switch opens when the temperature rises above said predetermined level, whereby less heat is provided for the zone. This arrangement provides a rapid warm up for the zone. Heat distribution in the zone is achieved by supporting the heating elements in zigzag fashion. Sagging of the elements thus mounted is prevented by bias means which maintain the elements under tension.