Abstract: A junction box is provided which allows serial connection of the individual conductors of at least one high temperature superconductor (HTS) wire bundle. The junction box includes an electrical interface device disposed within a junction box housing. The interface device is configured receive both ends of each conductor of each HTS wire bundle, and to provide a superconductive electrical connection between respective first ends of conductors to respective second ends of other wire bundle conductors to form at least one superconductive multi-turn electromagnetic winding.

Abstract: An improved power transfer mechanism is disclosed, which is particularly beneficial in power transmission applications. The mechanism allows the SCFCL system to have more than one electrical reference. The use of hydraulic power simplifies the design of systems in which one part of the system is referenced to ground, while a second part of the system is referenced to a different voltage, typically much higher than ground. For example, the tank of the SCFCL system may not be connected to ground, while hydraulic power supply is referenced to ground. This embodiment is performed without the use of an electrically conductive path between the two parts of the system.

Abstract: High-current, compact, flexible conductors containing high temperature superconducting (HTS) tapes and methods for making the same are described. The HTS tapes are arranged into a stack, a plurality of stacks are arranged to form a superstructure, and the superstructure is twisted about the cable axis to obtain a HTS cable. The HTS cables of the invention can be utilized in numerous applications such as cables employed to generate magnetic fields for degaussing and high current electric power transmission or distribution applications.

Abstract: A termination for a superconductive cable (1) is provided, consisting of a pressure-tight metal inner container (2) in which there is a liquid refrigerant and into which the cable protrudes, and a metal outer container (3) which is separated from the inner container by an intermediate space (4) in which vacuum insulation is applied. A first rupture diaphragm (6) is applied in the wall of the inner container (2) and a second rupture diaphragm (7) is applied in the wall of the outer container (3) level with the first rupture diaphragm (6). An evacuated relief space (8), which contains superinsulation and is sealed from the intermediate space (4) with the vacuum insulation by a pressure-tight wall (9), is provided between the two rupture diaphragms (6, 7).

Abstract: Electric fault current limiter has superconducting elements inside a cryogenic vessel and bushings for connecting an external circuit. The electric fault current limiter (1) includes a cryogenic vessel (2) and superconducting assemblies (5) including high temperature type superconducting elements (HTSC) immersed in a liquid coolant (6) such as liquefied nitrogen. Bushings (25, 28) with conductors (17, 18) are associated with a main body (3) of the vessel (2) such that the conductors (17, 18) extend horizontally from a surrounding space into an ullage space (8) situated between a level (7) of the liquid coolant (6) inside the vessel (2) and a cover (4). The arrangement of the bushings (25, 28) according to the invention allows for removing the cover (4) without dismantling electrical connections between the current limiter (1) and a circuit to be protected as is necessary with prior art limiters.

Abstract: A freely oriented portable superconducting magnet is disclosed. Coolant is supplied to the superconducting magnet from a repository separate from the magnet, enabling portability of the magnet. A plurality of support assemblies structurally anchor and thermally isolate the magnet within a thermal shield. A plurality of support assemblies structurally anchor and thermally isolate the thermal shield within a vacuum vessel. The support assemblies restrain movement of the magnet resulting from energizing and cooldown, as well as from changes in orientation, enabling the magnet to be freely orientable.

Abstract: A superconducting cable cooling system, wherein coolant continually provides cooling to superconducting cable, comprising a plurality of nodes within a superconducting cable network and a plurality of legs of superconducting cable which interconnect each of the nodes of the superconducting cable network.

Abstract: A device for feeding electricity under high voltage to a superconductive apparatus is situated in a cryostat. The device comprises two bushings each comprising a first connection terminal situated outside the cryostat, and a second connection terminal situated inside the cryostat. According to the invention, the distance D between the first connection terminals is greater than the distance d between the second connection terminals, the distances D and d being sufficient to avoid electric discharge either between the first terminals or between the second terminals. Advantageously, the cryostat includes an enlargement situated above the two bushings and between them.

Abstract: In accordance with the present invention, modular corona shields are employed in a HTS device to reduce the electric field surrounding the HTS device. In a exemplary embodiment a fault current limiter module in the insulation region of a cryogenic cooling system has at least one fault current limiter set which employs a first corona shield disposed along the top portion of the fault current limiter set and is electrically coupled to the fault current limiter set. A second corona shield is disposed along the bottom portion of the fault current limiter set and is electrically coupled to the fault current limiter set. An insulation barrier is disposed within the insulation region along at least one side of the fault current limiter set. The first corona shield and the second corona shield act together to reduce the electric field surrounding the fault limiter set when voltage is applied to the fault limiter set.

Abstract: A filter element (28) having planar (48) or cavity (30) geometry having applied thereto a coating (38, 39, 50, 53) of temperature super conducting (HTS) material in which the filter element (28) or coating of HTS material is provided with a porous structure (49A) or has associated therewith a plurality of cooling passages (29, 40, 42, 55) for passage of refrigerant when the filter element (28) is connected to a refrigeration circuit. A refrigeration circuit includes a compressor (18) connected to a heat exchanger assembly (19) located in an evacuated housing (20), wherein the heat exchanger assembly (19) includes an influent line (22), a first heat exchanger unit (21) in communication with the influent line (22), a throttle valve (23) which is in communication with the filter (28), a second heat exchanger unit (25) in communication with the filter (28) and a return line (26) to the compressor (18).

Abstract: A system and method for protecting a superconductor. The system may comprise a current sensor operable to detect a current flowing through the superconductor. The system may comprise a coolant temperature sensor operable to detect the temperature of a cryogenic coolant used to cool the superconductor to a superconductive state. The control circuit is operable to estimate the superconductor temperature based on the current flow and the coolant temperature. The system may also be operable to compare the estimated superconductor temperature to at least one threshold temperature and to initiate a corrective action when the superconductor temperature exceeds the at least one threshold temperature.

Abstract: A superconducting cable includes a cryogenic fluid, a superconducting conductor, and a cryostat. A layer impervious to the cryogenic fluid is provided between the superconducting conductor and the cryogenic fluid. The superconducting conductor operates in a space substantially free from fluids liquefying at a temperature greater than or equal to an operative temperature of the superconducting cable. A method for protecting a superconducting cable from formation of balloons includes isolating the superconducting conductor from the cryogenic fluid using a layer impervious to the cryogenic fluid and operating the superconducting conductor in a space substantially free from fluids liquefying at a temperature greater than or equal to an operative temperature of the superconducting cable. A current transmission/distribution network including at least one of the superconducting cables is also disclosed.

Abstract: The invention features a superconducting conductor for use in a preselected fluid cryogen including a composite ceramic superconducting wire having an outer surface along its length; and a sealing structure hermetically surrounding the outer surface to prevent the cryogen from infiltrating into the wire and degrading its superconducting properties, even under pressurized conditions. The superconducting conductor can be used in superconducting cabling and coil applications. The sealing structure can be formed by laminating metallic tapes to the wire, encircling at least one metallic sheet around the outer surface of the wire, welding a plurality of metallic sheets to one another to encircle the outer surface of the wire, or forming a polymer coating completely covering the outer surface of the wire.

Abstract: Method of maintaining a superconducting cryolink at low temperature by a flow of liquid nitrogen produced by a liquefier feeding one end of a link section, wherein the section is fed by a single liquefier and nitrogen is drawn off from at least one intermediate point of the link section.

Abstract: An electrical current limiting device comprises an electrical superconductor for attachment in an electrical circuit. The superconductor achieves a superconducting condition at relatively high temperatures. A cooling system includes a motor for flowing a cooled gas past the superconductor so that heat can be removed from the superconductor by a heat transfer process with the cooled gas.

Abstract: A superconducting current lead includes a cylindrical support member 3, and superconducting wire material units 1 each of which is fixed onto the support member and each of which is composed of a single tape-like oxide superconducting wire material or a laminated tape-like oxide superconducting wire material, wherein tape surf aces of the superconducting wire material units are disposed in parallel with a circumferential direction in a cylindrical coordinate system, and the cylindrical support member is formed from a low thermal conductivity material.

Abstract: A terminal for connecting a superconducting multiphase cable, a superconducting three-phase cable for example, to a room temperature electrical equipment is described. The terminal includes a casing with cooling fluid, inside which the three cable superconductors are each connected with a resistive conductor the end of which is connected to the room temperature equipment phases at the outside of the casing. The terminal includes superconducting connectors between the three neutral superconductors and a single resistive conductor the end of which is externally associated with the room temperature equipment. The neutral superconducting connectors and the junction area of the connector of the single conductor are disposed inside the cold area of the casing.

Abstract: A self-protected modular high temperature superconducting (HTS) down-lead that is capable of carrying large currents from a room temperature power source to a superconducting device operating at cryogenic temperatures. This down-lead incorporates a safety lead capable of carrying current and absorbing heat to protect the HTS material of the lead in the event of catastrophic failure of the HTS elements. The lead is in continuous contact with the HTS material and provides protection from interrupts and excess current. The down-lead is modular in design, and parts are easily replaced. Further, the down-lead is cooled through conduction in the middle stage, and gas cooled in the upper and lower stages by independent gas sources.

Abstract: An apparatus for mounting a superconducting element includes a first chamber which accommodates a first coolant and maintains the superconducting element at a very low temperature, a second chamber which accommodates a second coolant and is thermally connected to the first chamber via a barrier member, the second coolant being liquidized at a temperature lower than that of the first coolant, and a cooling device which is connected to the second chamber and liquidizes the first coolant.

Abstract: An electrical transmission line for conveying and limiting current by using a plurality of tubular portions made from a superconductive material. The tubular portions have a high critical temperature and are connected end-to-end by flexible, electrically conductive metal or alloy joints. A cryogenic fluid flows inside a first tube within the tubular portions. A vacuum is maintained inside a second tube around the tubular portions.

Abstract: A superconductive device (e.g., magnet) having a superconductive lead assembly and cooled by a cryocooler coldhead having first and second stages. A first ceramic superconductive lead has a first end thermally connected to the first stage and a second end thermally connected to the second stage. A jacket of open cell material (e.g., polystyrene foam) is in surrounding compressive contact with the first ceramic superconductive lead, and a rigid, nonporous support tube surrounds the jacket. This protects the first ceramic superconductive lead against shock and vibration while in the device. The rigid support tube has a first end and a second end, with the second end thermally connected to the second stage.

Abstract: In a low-temperature current transfer structure including a conductor with a cold end for connection to a superconductive component and a warm end for connection to a bus, there are provided heat exchange regions around the conductor at the cold end and a heat exchange region within the conductor at the warm end where the conductor is hollow cylindrical and, in a transition zone, includes passages for conducting coolant from the heat exchange regions around the conductor to the heat exchange region within the hollow conductor at the warm end to which electrical connectors are mounted on the outside. The arrangement permits heating of the coolant within the conductor close to ambient temperature so that no condensation or icing of the structure occurs and no insulation is needed at the connector end. Also the amount of coolant required is reduced so that also cooling equipment requirements are reduced.

Abstract: A new design for an aluminum stabilized superconductor which embeds the superconducting cable within a high purity aluminum stabilizer. This stabilizer is, in turn, partially surrounded by an aluminum alloy sheath. The aluminum alloy sheath is constructed and arranged so that at least one exterior surface of the stabilizer is open for exposure to a coolant. Preferably, this open exterior surface of the stabilizer will be knurled for greater cooling efficiency.

Abstract: A superconducting magnet is arranged in a helium tank, and the superconducting magnet cooled to a very low temperature by liquid helium in the helium tank is connected to a power source kept at room temperature by a current lead and a current lead. The current leads are constituted by conductors made of copper or a copper alloy having a residual resistivity of 5.times.10.sup.-8 .OMEGA..multidot.m or more. In a helium tank, a persistent current switch, cooled by liquid helium, for connecting the conductor to the conductor, is arranged. The persistent current switch magnetizes the superconducting magnet to a persistent current mode and demagnetizes it from the persistent current mode. The helium tank is arranged in a vacuum housing.

Abstract: A multiple circuit hybrid cryostat power lead has a plurality of laterally spaced, electrically isolated lead elements inside a tubular enclosure. Each lead element has an inner section with a high temperature superconducting (HTS) conductor inward of a divider in the tubular enclosure, and an outer normal conductor section outward of the divider. The outer sections of the lead elements have a pair of copper conductors spirally wound in an annular chamber between an electrically insulating central support and an electrically insulating sleeve to form helical flow passages. Cryogen vapor flows outward in the tubular enclosure inward of the divider over the HTS conductors, through a slotted heat exchanger electrically connecting the HTS and copper conductors at the divider, and through the helical flow passages to vents at outer terminals.

Abstract: A composite lead is provided which electrically links and conducts a current between about 75-80K. and liquid helium temperature of about 4.5K. The composite lead may be employed singly or in multiples concurrently to provide conduction of electrical current from normal conductors and semi-conductors at room temperature to superconductors operating at 4.5K. In addition, a variety of organizationl arrangements and assemblies are provided by which the mechanical strength and electrical reliability of the composite lead is maintained.

Abstract: Disclosed herein is a method of using an oxide superconducting conductor in a state including a transition region between a superconducting state and a normal conducting state, i.e., a flux flow state, by supplying the oxide superconducting conductor with a current exceeding its critical current. The oxide superconducting conductor can be used as a current lead for a superconducting magnet or the like, to extremely reduce current loss as compared with a conventional current lead of copper.

Abstract: A thermal plug which provides an electrical connection between first and second regions at different temperatures includes a plurality of interleaved heat transfer resistive laminae and heat conductive laminae. The laminae are stacked together to form a laminate and a plurality of superconducting strands are attached to the stack such that they are in thermal contact with the laminate. The superconducting strands are also in electrical contact with a conductor (e.g., a low temperature superconductor), in the first region and a conductor in the second region to allow the supply and withdrawal of electrical energy to and from the conductor in the first region.

Abstract: A current feed extends between a terminal at ambient temperature and an electrical equipment immersed in a cryogenic fluid and adapted to operate at variable current. The current feed is cooled by circulating an auxiliary cooling fluid at ambient temperature exchanging heat with the current feed. The auxiliary cooling fluid is introduced at an intermediate level of the current feed when the current exceeds a particular threshold and optionally all or some of the auxiliary cooling fluid is introduced at other levels nearer the electrical equipment at higher currents.

Abstract: A vapor cooled current lead for a superconducting device located in a cryostat includes a normal conductor section extending from ambient conditions inward to an intermediate point, and a composite lead having a ceramic high temperature superconductor core with a metallic sheath extending between the normal conductor section and the superconducting device, preferably in a helical path to reduce heat leak by conduction. The metallic sheath is stripped away at spaced intervals, preferably adjacent the low temperature end of the composite lead, and the gaps are filled with a filler which provides mechanical strength for the core and reduces thermal conduction. A flow of cryogen vapor directed by a tubular housing maintains the high temperature superconducting material below its critical temperature, and cools the normal conductors.

Abstract: An electrical conductor particularly suited for use as a downlead to low temperature devices includes a ceramic honeycomb body having longitudinal channels wherein films of substantially single crystals of a ceramic superconductor are grown. The maximum current carrying capacity of the ceramic superconductor may be oriented parallel to the channels. Square channels arranged in alternating rows of oppositely directed current provide desirable magnetic field cancellations and permit high current flows. A method for making the electrical conductor and a method of extruding the ceramic honeycomb body are also disclosed.

Abstract: A superconductive transmission line is formed of mixed metallic oxide ceramic material, particularly Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x drawn epitaxially upon a substrate. The superconductive material has basal crystallographic planes in alignment with copper oxide of the ceramic material. The planes are parallel to the substrate. The transmission line is constructed of a plurality of electrically conductive elements, each of which is formed of the superconductive material. The conductive elements are arranged with the crystalline planes parallel to an axis of the transmission line, along which axis power is to flow. Thereby, magnetic fields induced by currents flowing in the conductive elements intersect the conductive elements perpendicularly to the basal crystallographic planes to maximize the current which can flow while retaining linearity between magnetization and applied magnetic field.

Abstract: Superconducting fluids are disclosed. The fluid is made by dispersing a superconducting oxide ceramic powder in a liquid nitrogen. A magnetic field shielding device is constructed by disposing the fluid in a suitable container which is adapted to have the superconducting fluid surrounding a space to be shielded from an external magnetic field.

Abstract: An improved transmission system for electrical energy comprising a plurality of ball members interspersed by mating members enclosed within at least one protective outer wrapping, with the ball members and the mating members being in contact with adjacent members and being formed of material which is electrically conductive at superconductor temperatures and each having an axial opening extending therethrough to permits passage of a suitable coolant fluid, such as liquid helium.

Abstract: A transmission line using superconductors instead of conventional conductors substantially reduces ohmic losses compared to conventional conductors. The superconductors are cooled by refrigerant flowing through a hollow superconducting inner conductor. The refrigerant is transported to the inner conductor using a novel connector.

Abstract: A superconductive conductor (1) is formed by at least three superconducting wires (3) comprising oxide superconductor members (4) and stabilizing members (5), which are point-symmetrically arranged in section. The superconducting wires (3) are so point-symmetrically arranged that electromagnetic force and magnetic fields provided by the respective superconducting wires (3) cancel each other, whereby it is possible to reduce distortion and influence by applied magnetic fields.

Abstract: A superconducting conductor comprises a first fraction of prior-tinned strands (1, 3, 5, 7, 9, etc. . . . ) and an additional fraction of non-prior-tinned strands (2, 4, 6, 8, 10, etc., . . . ). The strands of the first fraction and of the additional fraction alternate regularly and are maintained in a coherent assembly after being assembled with transposition by heating to melt the layer of tin on the prior-tinned strands, with the tin from said layer then solidifying, thus providing substantially point adherence between the previously tinned strands while leaving channels (11, 12, etc. . . . ) inside the superconducitng conductor for cooling liquid circulation. The invention is also to a method of manufacturing such a superconducting conductor.

Abstract: A lead interface for a superconducting device has a segment of normal conducting lead electrically connected to a segment of superconducting lead coiled within a dewar. The superconducting lead is adapted to be cooled to below the superconductor critical temperature by circulating a cooling fluid through an internal fluid chamber which runs the length of the superconducting coil and into an intermediate disk having an internal spiral fluid chamber. When the superconducting device is on standby, a superconducting switch is closed and the superconducting segment of the interface is left uncooled. To charge or discharge the superconducting device, the superconducting segment of the interface is cooled prior to opening the superconducting switch.

Abstract: A pipe comprises a hollow support member made from a member selected from copper and copper compounds and a copper oxide superconducting ceramic material which covers the inner surface of the support member with a space kept in the pipe for use in a magnet or power accumulator device.

Abstract: A spacer bar, or system of spacer bars, interposed between coil layers of a coil structure. The spacer bar comprises a block of electrical insulating material adapted to be arranged between adjacent layers of a coil. The spacer bar may comprise several spacer bar sections segmented axially and provided with flexible joints (e.g., Belleville washers) between sections to permit each section to move with the adjacent coil layers (the coil layers between which the section is interposed). The sections of the spacer bar are held together by passing a rod through holes provided through each section. Between each pair of spacer sections, a Belleville washer is installed to assure that under continued cycling (e.g., expansion and contraction of the coil), the spacer sections return to their original location. To maintain an adequate creep path at the ends of the blocks or sections, notches can be cut into a face of each block or section.

Abstract: An electronic system having components operating at low temperature at various locations within the system, cryogenic fluid and electrical power are distributed by means of the same conduit. In one embodiment, the conduit consists of a supply section and a return section with each section comprising a channel for conveying cryogenic fluid having superconducing walls for conveying electrical power. In another embodiment of the invention, the conduit comprises a copper rod having channels formed therein for the transport of cryogenic fluid and a channel for supporting a rod of superconducing material therein. The superconducing rod conducts electrical current to a subsystem while being cooled by cryogenic fluid in nearby channels and the cryogenic fluid is used at its destination for cooling purposes.

Abstract: A current-carrying lead that may be connected between a source of current and a superconducting device and which comprises a ceramic superconductor and a support made of an insulator, a nonmagnetic metal or a good electrical conductor. The lead may be contructed to conduct currents having a single or dual polarities.

Abstract: A superconducting transmission line system for transferring electrical power over long distances. The system includes a superconducting transmission line extending from a first location where power is supplied to the line to a second location where electrical power is taken from the line. The line includes an inner tube, and a superconducting core positioned inside the tube and spaced from the inner surface of the tube. The core and the inner tube define a passageway for a cryogenic liquid, the boiling temperature of which is above the superconducting transition temperature of the core. The transmission line system also includes a number of spaced supports holding the transmission line with the portion of the transmission line extending between a pair of adjacent supports being lower than the parts of the line held by the pair of adjacent supports. A regenerator for the cryogenic liquid is mounted on each of the pair of supports.

Abstract: In a superconducting coil refrigerating method and a superconducting apparatus, a flow of liquid helium is induced in a helium vessel only at a specified time upon change of a current of the superconducting coil, before the current change and/or after the current change. The induction of the helium flow before the current change provides a condition that the transfer of helium gas bubbles which may be generated upon subsequent current change is rapidly effected. The induction of the helium flow upon the current change or after the current change results in the rapid exhaustion of helium gas bubbles which continue to generate or have been generated. With such a construction, even if a superconducting pulse magnet is used, any influence of helium gas bubbles produced due to an AC loss upon change of a current can be eliminated, thereby providing a coil which is stable to a pulse-excited magnetization thereof.

Abstract: A railgun with superconducting rails. The device features rails made from ceramic materials capable of becoming superconducting at relatively high temperatures. Some embodiments utilize rails made entirely from superconducting ceramics while other embodiments utilize rails with metallic cores covered by layers of superconducting ceramics. Cooling of the superconducting ceramic to a temperature below its critical temperature is accomplished by liquid nitrogen cryorefrigerator or a compressed gas cryorefrigerator.

Abstract: A ceramic type superconductive layer (2) is formed on the outer peripheral surface of an optical fiber (1), and a stabilizing layer (3) is formed so that it contacts the outer peripheral surface of the superconductive layer (3). The diameter of the optical fiber is, for example, not more tha 100 .mu.m. The superconductive layer may be formed with a spirally extending groove (7) which divides the superconductive layer.

Abstract: A railgun with superconducting rails. The device features rails made from ceramic materials capable of becoming superconducting at relatively high temperatures. Some embodiments utilize rails made entirely from superconducting ceramics while other embodiments utilize rails with metallic cores covered by layers of superconducting ceramics. Cooling of the superconducting ceramic to a temperature below its critical temperature is accomplished by liquid nitrogen cryorefrigerator or a compressed gas cryorefrigerator.