Abstract: Several embodiments of a novel technique for limiting transmission of fault current are disclosed. Current power distribution systems typically have an impedance, or reactor, on the output of the network equipment to limit current in the case of a fault condition. A low resistance switch, which changes its resistance in the presence of high current, is connected in parallel with this reactor. Thus, in normal operation, the current from the power generator bypasses the reactor, thereby minimizing power loss. However, in the presence of a fault, the resistance of the switch increases, forcing the current to pass through the reactor, thereby limiting the fault current.

Abstract: A superconducting article and method of fabrication are provided. The superconducting article includes a superconducting structure, which includes a superconducting conductor and multiple discrete overlay regions of higher heat capacity than the superconducting conductor. The multiple discrete overlay regions are disposed along a length of the superconducting conductor, in thermal contact with the superconducting conductor, and positioned to define a heat modulation pattern along the length of the superconducting structure. The multiple discrete overlay regions create a temperature distribution favorable to transition of the superconducting structure under load from a normal resistive state to a superconductive state by facilitating formation of a continuous superconducting path along the length of the superconducting structure.

Abstract: An elongated current limiting composite material comprising one or more high-temperature superconductor filaments and a second electrically conductive member, which may include a sheath of high bulk resistivity surrounding the filament. The current limiter exhibits dissipation in the range of 0.05-0.5 V/cm at currents of 3-10 times the operating current, thereby minimizing fault currents and improving recovery capability.

Abstract: A current-limiting device contains at least one conductor track including high Tc superconductor material, on a support body. The conductor track is provided with a cover layer including an insulating plastic material, which includes a filler which increases the thermal conductivity. The thickness of the cover layer is greater than the thickness of the conductor track.

Abstract: The superconductor structure for conducting an electric current in a predetermined direction has a metallic support and one or more conductor tracks. The conductor tracks have at least one electrically insulating interlayer deposited on the support and a high Tc superconductor layer deposited on the interlayer. Between its superconducting layer and the support, the conductor track has at least one connecting part, which extends in the current-conducting direction, for electrically connecting the superconducting layer and the support in parallel. The superconductor structure may be provided in particular for a current limiter device.

Abstract: On transition from the superconducting state to the normal conducting state, current limiters having a high-temperature superconductor increase their electrical resistance and thereby limit an electric current which is flowing through them. To provide electrical stabilization, the high-temperature superconductor is combined with a silver foil having a layer thickness of <50 &mgr;m to form an extensive composite conductor with good conductivity. The ratio of the layer thickness of the high-temperature superconductor to that of the silver foil should be >10. To produce this composite conductor, the silver sheet is placed on one side on a 2 mm thick MgO powder layer and, on the other side, is covered with a 600 &mgr;m thick so-called green sheet which contains a high-temperature superconductor powder and an organic binder.

Abstract: A current limiting device having an electrical superconductor for attachment in an electrical circuit, the superconductor being made of material having a critical current density which varies with applied magnetic field. A magnetic field generator generates a magnetic field to which the superconductor is exposed. Under normal working conditions a magnetic field applied causes the critical current density to be less than a maximum critical current density. A controller adjusts the critical current density such that after a current carried by the superconductor exceeds the critical current density so that the superconductor transforms to a resistive state, the controller can be activated to increase the critical current density causing the superconductor to return the superconducting condition without terminating the flow of current through the superconductor.

Abstract: A current limiting device including at least one superconductor and at least one nonsuperconducting shunt resistor in parallel with each superconductor. Each superconductor has a first main superconductor face in contact with a main shunt resistor face of a shunt resistor so as to form a compound conductor generally in the form of a meandering band having a band width greater than approximately 3.5 times the superconductor thickness. At least one insulator has opposing faces each in contact with a compound conductor. Multiple compound conductors are arranged such that current flows in opposite directions through adjacent compound conductors.

Abstract: A superconducting current limiter comprising a bar or tube of high temperature superconducting material of the composite type made up of glass and a high temperature superconducting oxide, the volume fraction of the glass lying in the range 10% to 40%, the bar or tube being selected to comply with the following inequalities:.rho.>10.sup.-4 .OMEGA..multidot.mj.sub.c >10.sup.+5 A/m.sup.2.rho.x.sup.2 <10.sup.11 W/m.sup.3in which inequalities:.rho. designates the resistivity of the material in the normal, i.e. the non-superconducting, state;j.sub.c designates the critical current density;.rho.x.sup.2 designates the power density dissipated in the bar or tube during the transition stage;it being specified that the critical current density is defined as the density which produces an electric field of 10.sup.-4 V/m along the tube or bar and that it is accepted that limitation takes place for a current density equal to five times the critical current density.

Abstract: Improved methods, apparatus, and compositions for achieving superconductivity are disclosed. The methods and apparatus are based upon applying an external driving force, i.e., either an electrical current or a magnetic field, at a predetermined frequency. The predetermined frequency is chosen to equal one or more of the resonant frequencies of the molecular vibration of the atoms which provide conductivity to the material. The compositions of the invention require a continuous bridge or network of electrically compatible atoms between the opposite poles of the electrical pathway. Another aspect of the invention provides a method for determining the resonant frequency of molecular vibration, i.e., the frequency at which the external driving force should be applied. In this aspect of the invention, the composition is exposed to one or more sources of electromagnetic energy which radiate at known frequencies. The response of the composition to the various frequencies of radiation is measured and compared.

Abstract: The invention relates to superconductor current-limiting apparatus of the type having a magnetic core around which firstly a superconductor component is disposed, followed by an electric coil made of non-superconducting material, the apparatus being designed to be inserted in a line to be protected (L), the assembly constituted by the magnetic core (6A, 6B), the superconductor component (3A, 3B) and the electric coil (2A, 2B) forming a current-limiting unit which is connected in the line to be protected in series with a circuit-breaker.

Abstract: A superconductive magneto-resistive device includes superconductive ceramic films having a magneto-resistive effect. In the superconductive magneto-resistive device, the superconductive ceramic films are laminated one by one, and the adjacent superconductive ceramic films are insulated by each electrical insulation film, respectively, except for one portion of each of the adjacent superconductive ceramic films, resulting in that the superconductive ceramic films are connected in series. Furthermore, a pair of electrodes is arranged on the upper-most and lower-most superconductive ceramic films.

Abstract: A superconductive apparatus has a superconductive device such as a superconductive magneto-resistive device. The superconductive device is mounted within an airtight package which is sealed to create an airtight state. Before sealing, the airtight package is evacuated to replace the internal air thereof with an inert gas.

Abstract: A magnetic image detection device which measures a magnetic image in the first or second dimension by using a superconducting body. In the magnetic image detection device, multiple band-shaped superconducting bodies are provided in parallel on a nonmagnetic dielectric substrate, and electrodes are provided on both ends of the superconducting bodies so as to form pairs. A detection circuit detects resistance between the electrodes on both ends of the multiple superconducting bodies according to intensity of external magnetic field.

Abstract: A superconducting current limiting apparatus includes a first container, a superconducting current limiting element accommodated in the first container, a refrigerant filling the first container for cooling the superconducting current limiting element accommodated in the first container, a second container for accommodating the first container in such a manner that the first container is heat insulated, and a conductor for connecting the superconducting current limiting element to an external power supply system. Such a superconducting current limiting apparatus can be used to limit a short-circuit current. It can be incorporated in a short circuit controlling superconducting system.

Abstract: A CMOS circuit including a variable conductor means interposed between a power supply and the CMOS circuit. The CMOS circuit comprises a P channel MOS FET and an N channel MOS FET laterally formed on the surface of a semiconductor substrate, inherently producing a parasitic thyristor which can be latched-up with destructive consequences under certain circumstances. The variable conductor means, interposed between the power supply and CMOS circuit, preferably includes a superconductor arranged to sharply switch to a normal conductor mode when the current level exceeds a critical current level, established to be less than the latch-up holding current of the parasitic thyristor, thereby to prevent latch-up.

Abstract: A current limiter comprising a cryostat provided with a first insulating feedthrough for an inlet conductor and a second insulating feedthrough for an outlet conductor, and a conductor running from one feedthrough to the other inside the tank, said conductor being constituted at least in part by a superconducting material, the cryostat being filled with a fluid at a temperature which is low enough to maintain said material in the superconducting state, said portion made of superconducting material including at least one portion comprising superconducting wires (7, 8) wound in opposite direction windings on two coaxial insulating formers (14, 15). Respective the ends of each of the superconducting wires (7, 8) are connected firstly to the inlet conductor and secondly to the outlet conductor via identical elementary current feeds (21A, 22A).