Abstract: A superconducting machine of the type having a stator assembly and a rotor assembly that rotates within the stator assembly and is spaced from the stator assembly by a gap is disclosed. This arrangement can be used, for example, to produce a superconducting motor or generator. In one aspect of the invention, the superconducting rotating machine includes at least one HTS superconducting winding assembly which, in operation, generates a magnetic flux linking the stator assembly and rotor assembly, a refrigeration system for cooling the at least one superconducting winding of the rotor assembly and the superconducting rotating machine has a torque density of approximately 75 Nm/Kg or more at 500 RPM or less.

Abstract: Superconducting coils and methods of manufacture include a superconductor tape wound concentrically about and disposed along an axis of the coil to define an opening having a dimension which gradually decreases, in the direction along the axis, from a first end to a second end of the coil. Each turn of the superconductor tape has a broad surface maintained substantially parallel to the axis of the coil.

Abstract: A superconducting coil assembly is of the type mounted to a rotor assembly of an electric rotating machine and, in operation, is maintained at cryogenic temperatures while the portion of the rotor assembly is maintained above cryogenic temperatures. The superconducting coil assembly includes at least one superconducting winding wound about a longitudinal axis of the coil assembly and having an inner radial surface defining a bore extending through the coil assembly. The coil assembly also includes at least one support member extending across the bore and mechanically coupled to the portion of the rotor assembly and to opposing portions of the inner radial surface of the at least one superconducting winding.

Abstract: A superconducting rotating machine includes a stator assembly. This stator assembly includes at least one stator coil assembly having a first predefined length. A rotor assembly is configured to rotate within this stator assembly and is spaced from the stator assembly by a gap. The rotor assembly includes at least one superconducting rotor winding assembly that, in operation, generates a magnetic flux linking the stator assembly. The rotor assembly includes an asynchronous field filtering shield having a second predefined length that is less than the first predefined length. This shield is positioned between the stator assembly and the rotor assembly.

Abstract: A superconducting rotating machine has a relatively compact construction while still providing a relatively high output power, thus the superconducting rotating machine has an increased power density characteristic. The superconducting rotating machine includes a stator assembly, a rotor assembly configured to rotate within the stator assembly and having at least one HTS superconducting winding assembly which, in operation, generates a magnetic flux linking the rotor assembly to the stator assembly, and a refrigeration system for cooling the at least one superconducting winding. The superconducting rotating has a gap shear characteristic greater than 10 psi.

Abstract: Superconducting coils and methods of manufacture include a superconductor tape wound concentrically about and disposed along an axis of the coil to define an opening having a dimension which gradually decreases, in the direction along the axis, from a first end to a second end of the coil. Each turn of the superconductor tape has a broad surface maintained substantially parallel to the axis of the coil.

Abstract: This invention relates to a practical superconducting conductor based upon biaxially textured high temperature superconducting coatings. In particular, methods for producing flexible and bend strain-resistant articles and articles produced in accordance therewith are described which provide improved current sharing, lower hysteretic losses under alternating current conditions, enhanced electrical and thermal stability and improved mechanical properties between otherwise isolated films in a coated high temperature superconducting (HTS) wire. Multilayered materials including operational material which is sensitive to bend strain can be constructed, in which the bend strain in the region in which such operational material is located is minimized. The invention also provides a means for splicing coated tape segments and for termination of coated tape stack ups or conductor elements.

Abstract: An oxide superconducting cable is provided having a plurality of strands comprised of at least one oxide superconductor filament sheathed in a ductile and conductive metal matrix and least one of said strand further comprising a substantially continuous high resistivity coating substantially surrounding said at least one strand. The strands are positioned and arranged to form a cable. The cable is prepared by (a) applying a ductile predecessor coating to a plurality of strands, each said strand comprised of at least one oxide superconductor filament or a precursor thereto sheathed in a ductile metal matrix, and the ductile predecessor capable of conversion into a high resistivity material; (b) assembling the plurality of strands into a cable; and (c ) converting the ductile predecessor into a high resistivity material, where steps (a) and (b) can be performed in any order.

Abstract: The invention provides a multifilamentary superconducting composite article comprising multiple substantially electrically decoupled domains, each including one or more fine, preferably twisted filaments of a desired superconducting oxide material. In a preferred embodiment, the article comprises a matrix, which substantially comprises a noble metal, a conductive jacketing layer surrounding the matrix, a plurality of discrete filament decoupling layers, each comprising an insulating material, disposed within the matrix to separate the matrix into a plurality of substantially electrically decoupled domains; a plurality of filaments, each comprising a desired superconducting oxide, which are disposed within and essentially encapsulated by the matrix and chemically isolated thereby from the decoupling layers, each of the electrically decoupled domains containing at least one filament.

Abstract: A cabled conductor comprises a plurality of transposed strands each comprising one or more preferably twisted filaments preferably surrounded or supported by a matrix material and comprising textured anisotropic superconducting compounds which have crystallographic grain alignment that is substantially unidirectional and independent of the rotational orientation of the strands and filaments in the cabled conductor. The cabled conductor is made by forming a plurality of suitable composite strands, forming a cabled intermediate from the strands by transposing them about the longitudinal axis of the conductor at a preselected strand lay pitch, and, texturing the strands in one or more steps including at least one step involving application of a texturing process with a primary component directed orthogonal to the widest longitudinal cross-section of the cabled intermediate, at least one such orthogonal texturing step occurring subsequent to said strand transposition step.

Abstract: A cabled conductor is provided for use in a cryogenically cooled circuit including refrigeration having a predetermined operating temperature and efficiency. The conductor includes multiple conductor strands cabled about the longitudinal axis of the conductor at a preselected cabling period, each strand including a composite of superconducting ceramic in intimate contact with conductive matrix material. Each filament has high performance regions in which the filament material is well-textured with its preferred direction aligned perpendicular to the widest longitudinal cross-section of the conductor alternating with poorly superconducting regions which are at least about half the diameter of a filament in length and in which the superconducting ceramic filament is strained by transposition in excess of its critical strain limit. In the poorly superconducting regions, the conductive matrix material provides an alternate current path.

Abstract: An electric coil includes bifilar pancake coils electrically connected to an adjacent pancake coil so that current flowing in adjacent turns of adjacent pancake coils flows in opposite directions at all radial region of the coil assembly. The superconducting fault current limiter is configured to provide a minimized inductance and low resistance in a normal state of operation. On the other hand, when a fault current exceeds a predetermined threshold, the resistance increases to a level sufficient for limiting the flow of fault current to a desired level until a circuit breaker connected within the electrical system opens the circuit.

Abstract: A cabled conductor comprises a plurality of transposed strands each comprising one or more preferably twisted filaments preferably surrounded or supported by a matrix material and comprising textured anisotropic superconducting compounds which have crystallographic grain alignment that is substantially unidirectional and independent of the rotational orientation of the strands and filaments in the cabled conductor. The cabled conductor is made by forming a plurality of suitable composite strands, forming a cabled intermediate from the strands by transposing them about the longitudinal axis of the conductor at a preselected strand lay pitch, and, texturing the strands in one or more steps including at least one step involving application of a texturing process with a primary component directed orthogonal to the widest longitudinal cross-section of the cabled intermediate, at least one such orthogonal texturing step occurring subsequent to said strand transposition step.

Abstract: A superconducting ceramic includes a laminate and a superconducting ceramic tape joined to the laminate. The laminate and superconductor tape are joined such that the tape is under a compressive stress. The compressive stress is of a greater amount than compressive stress which results from differences in thermal expansion of the tape and the laminate. The greater compressive stress can be achieved by putting the laminate under a greater tension than the superconducting ceramic tape during joining of the superconducting ceramic tape to the laminate.

Abstract: A method for preparing an oxide superconductor cable includes transposing a plurality of oxide superconductor strands along a longitudinal axis so as to form a cable and exposing the cable to a two step heat treatment after cabling of the oxide strands, the heat treatment comprising, (a) heating the cable to and maintaining the cable at a first temperature sufficient to partially melt the article, such that a liquid phase co-exists with the desired oxide superconductor phase; and (b) cooling the cable to and maintaining the cable at a second temperature sufficient to substantially transform the liquid phase into the desired oxide superconductor.

Abstract: The invention provides an apparatus for supplying power to superconducting loads includes a current source, a cryogenic region (e.g., a cryogenic chamber), a first switching device in series between the current source and a superconducting load, and a second switching device in parallel with the superconducting load. The switching devices are arranged so that, when the first is closed and the second is open, recharging current is supplied to the superconducting load. The second switching device serves as a shunt. When it is closed and the first is open, current recirculates through the persistent (or partially persistent) superconducting load. The invention also provides a superconducting magnet incorporating such a power supply.

Abstract: A superconducting magnetic coil includes a first superconductor formed of an anisotropic superconducting material for providing a low-loss magnetic field characteristic for magnetic fields parallel to the longitudinal axis of the coil and a second superconductor having a low loss magnetic field characteristic for magnetic fields perpendicular to the longitudinal axis of the coil. The first superconductor has a normal state resistivity characteristic conducive for providing current limiting in the event that the superconducting magnetic coil is subjected to a current fault.

Abstract: A multifilamentary superconducting composite article comprising multiple substantially electrically decoupled domains, each including one or more fine, preferably twisted filaments of a desired superconducting oxide material. In a preferred embodiment, the article comprises a matrix, which substantially comprises a noble metal, a conductive jacketing layer surrounding the matrix, a plurality of discrete filament decoupling layers, each comprising an insulating material, disposed within the matrix to separate the matrix into a plurality of substantially electrically decoupled domains; a plurality of filaments, each comprising a desired superconducting oxide, which are disposed within and essentially encapsulated by the matrix and chemically isolated thereby from the decoupling layers, each of the electrically decoupled domains containing at least one filament.

Abstract: A superconducting ceramic includes a laminate and a superconducting ceramic tape joined to the laminate. The laminate and superconductor tape are joined such that the tape is under a compressive stress. The compressive stress is of a greater amount than the compressive stress which results from differences in thermal expansion of the tape and the laminate. The greater compressive stress can be achieved by putting the laminate under a greater tension than the superconducting ceramic tape during joining of the superconducting ceramic tape to the laminate.

Abstract: The invention provides an apparatus for supplying power to superconducting loads includes a current source, a cryogenic region (e.g., a cryogenic chamber), a first switching device in series between the current source and a superconducting load, and a second switching device in parallel with the superconducting load. The switching devices are arranged so that, when the first is closed and the second is open, recharging current is supplied to the superconducting load. The second switching device serves as a shunt. When it is closed and the first is open, current recirculates through the persistent (or partially persistent) superconducting load. The invention also provides a superconducting magnet incorporating such a power supply.