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Sample records for superconducting ac machine

  1. Superconducting three element synchronous ac machine

    International Nuclear Information System (INIS)

    Boyer, L.; Chabrerie, J.P.; Mailfert, A.; Renard, M.

    1975-01-01

    There is a growing interest in ac superconducting machines. Of several new concepts proposed for these machines in the last years one of the most promising seems to be the ''three elements'' concept which allows the cancellation of the torque acting on the superconducting field winding, thus overcoming some of the major contraints. This concept leads to a device of induction-type generator. A synchronous, three element superconducting ac machine is described, in which a room temperature, dc fed rotating winding is inserted between the superconducting field winding and the ac armature. The steady-state machine theory is developed, the flux linkages are established, and the torque expressions are derived. The condition for zero torque on the field winding, as well as the resulting electrical equations of the machine, are given. The theoretical behavior of the machine is studied, using phasor diagrams and assuming for the superconducting field winding either a constant current or a constant flux condition

  2. Preliminary study on AC superconducting machines

    International Nuclear Information System (INIS)

    Yamamoto, M.; Ishigohka, T.; Shimohka, T.; Mizukami, N.; Yamaguchi, M.

    1988-01-01

    This paper describes the issues involved in developing AC superconducting machines. In the first phase, as a preliminary experiment, a 4kVa AC superconducting coil which employs 100A class 50/60Hz superconductors is made and tested. And, in the second phase, as an extension of the 4kVa coil, a model superconducting transformer is made and examined. The transformer has a novel quench protection system with an auxiliary coil only in the low voltage side. The behavior of the overcurrent protection system is confirmed

  3. AC Loss Analysis of MgB2-Based Fully Superconducting Machines

    Science.gov (United States)

    Feddersen, M.; Haran, K. S.; Berg, F.

    2017-12-01

    Superconducting electric machines have shown potential for significant increase in power density, making them attractive for size and weight sensitive applications such as offshore wind generation, marine propulsion, and hybrid-electric aircraft propulsion. Superconductors exhibit no loss under dc conditions, though ac current and field produce considerable losses due to hysteresis, eddy currents, and coupling mechanisms. For this reason, many present machines are designed to be partially superconducting, meaning that the dc field components are superconducting while the ac armature coils are conventional conductors. Fully superconducting designs can provide increases in power density with significantly higher armature current; however, a good estimate of ac losses is required to determine the feasibility under the machines intended operating conditions. This paper aims to characterize the expected losses in a fully superconducting machine targeted towards aircraft, based on an actively-shielded, partially superconducting machine from prior work. Various factors are examined such as magnet strength, operating frequency, and machine load to produce a model for the loss in the superconducting components of the machine. This model is then used to optimize the design of the machine for minimal ac loss while maximizing power density. Important observations from the study are discussed.

  4. AC Losses and Their Thermal Effect in High Temperature Superconducting Machines

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Zou, Shengnan

    2015-01-01

    In transient operations or fault conditions, high temperature superconducting (HTS) machines suffer AC losses which have an influence on the thermal stability of superconducting windings. In this paper, a method to calculate AC losses and their thermal effect in HTS machines is presented....... The method consists of three sub-models that are coupled only in one direction. The magnetic field distribution is first solved in a machine model, assuming a uniform current distribution in HTS windings. The magnetic fields on the boundaries are then used as inputs for an AC loss model which has...

  5. AC Losses and Their Thermal Effect in High-Temperature Superconducting Machines

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Zou, Shengnan

    2016-01-01

    In transient operations or fault conditions, hightemperature superconducting (HTS) machines suffer ac losses, which have an influence on the thermal stability of superconducting windings. In this paper, a method to calculate ac losses and their thermal effect in HTS machines is presented....... The method consists of three submodels that are coupled only in one direction. The magnetic field distribution is first solved in a machine model, assuming a uniform current distribution in HTS windings. The magnetic fields on the boundaries are then used as inputs for an ac loss model that has a homogeneous...

  6. Superconducting machines. Chapter 4

    International Nuclear Information System (INIS)

    Appleton, A.D.

    1977-01-01

    A brief account is given of the principles of superconductivity and superconductors. The properties of Nb-Ti superconductors and the method of flux stabilization are described. The basic features of superconducting d.c. machines are illustrated by the use of these machines for ship propulsion, steel-mill drives, industrial drives, aluminium production, and other d.c. power supplies. Superconducting a.c. generators and their design parameters are discussed. (U.K.)

  7. Design and AC loss analysis of a superconducting synchronous motor

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Q [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Majoros, M [Department of Materials Science and Engineering, Ohio State University (United States); Hong, Z [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Campbell, A M [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Coombs, T A [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2006-11-15

    This paper gives a conceptual design of a superconducting synchronous motor consisting of both high-temperature superconducting rotating field winding and armature winding. The AC losses of the armature winding of the motor have been investigated experimentally and numerically, by considering the self-field of the superconducting coils and the rotating magnetic field exposed on the armature winding. The recent developments of YBCO-coated conductors present the possibility of achieving a wholly superconducting machine of significantly smaller size and weight than a conventional machine. Both the rotating field winding and the armature winding are composed of YBCO high-temperature superconducting (HTS) coils. A low AC loss armature winding design has been developed for this superconducting synchronous motor. The performance of the machine was investigated by modelling with the finite-element method. The machine's torque is calculated from first principles by considering the angle between the field and the armature main flux lines.

  8. Static Measurements on HTS Coils of Fully Superconducting AC Electric Machines for Aircraft Electric Propulsion System

    Science.gov (United States)

    Choi, Benjamin B.; Hunker, Keith R.; Hartwig, Jason; Brown, Gerald V.

    2017-01-01

    The NASA Glenn Research Center (GRC) has been developing the high efficiency and high-power density superconducting (SC) electric machines in full support of electrified aircraft propulsion (EAP) systems for a future electric aircraft. A SC coil test rig has been designed and built to perform static and AC measurements on BSCCO, (RE)BCO, and YBCO high temperature superconducting (HTS) wire and coils at liquid nitrogen (LN2) temperature. In this paper, DC measurements on five SC coil configurations of various geometry in zero external magnetic field are measured to develop good measurement technique and to determine the critical current (Ic) and the sharpness (n value) of the super-to-normal transition. Also, standard procedures for coil design, fabrication, coil mounting, micro-volt measurement, cryogenic testing, current control, and data acquisition technique were established. Experimentally measured critical currents are compared with theoretical predicted values based on an electric-field criterion (Ec). Data here are essential to quantify the SC electric machine operation limits where the SC begins to exhibit non-zero resistance. All test data will be utilized to assess the feasibility of using HTS coils for the fully superconducting AC electric machine development for an aircraft electric propulsion system.

  9. ac superconducting articles

    International Nuclear Information System (INIS)

    Meyerhoff, R.W.

    1977-01-01

    A noval ac superconducting cable is described. It consists of a composite structure having a superconducting surface along with a high thermally conductive material wherein the superconducting surface has the desired physical properties, geometrical shape and surface finish produced by the steps of depositing a superconducting layer upon a substrate having a predetermined surface finish and shape which conforms to that of the desired superconducting article, depositing a supporting layer of material on the superconducting layer and removing the substrate, the surface of the superconductor being a replica of the substrate surface

  10. Dynamoelectric machine with a superconductive field winding that can operate in either a synchronous or an asynchronous mode

    International Nuclear Information System (INIS)

    Mole, C.J.; Haller, H.E. III.

    1977-01-01

    Two parallel magnetic flux paths are provided in a dynamoelectric machine having a superconductive field winding. A first, or main, magnetic flux path includes at least one area of nonferromagnetic or diamagnetic material. A second, or shunt, magnetic flux path prevents the relatively low frequency ac flux present during starting or asynchronous operation of the machine, when used as an ac motor, from penetrating the superconductive winding

  11. Superconducting rotating machines

    International Nuclear Information System (INIS)

    Smith, J.L. Jr.; Kirtley, J.L. Jr.; Thullen, P.

    1975-01-01

    The opportunities and limitations of the applications of superconductors in rotating electric machines are given. The relevant properties of superconductors and the fundamental requirements for rotating electric machines are discussed. The current state-of-the-art of superconducting machines is reviewed. Key problems, future developments and the long range potential of superconducting machines are assessed

  12. Introduction to AC machine design

    CERN Document Server

    Lipo, Thomas A

    2018-01-01

    AC electrical machine design is a key skill set for developing competitive electric motors and generators for applications in industry, aerospace, and defense. This book presents a thorough treatment of AC machine design, starting from basic electromagnetic principles and continuing through the various design aspects of an induction machine. Introduction to AC Machine Design includes one chapter each on the design of permanent magnet machines, synchronous machines, and thermal design. It also offers a basic treatment of the use of finite elements to compute the magnetic field within a machine without interfering with the initial comprehension of the core subject matter. Based on the author's notes, as well as after years of classroom instruction, Introduction to AC Machine Design: * Brings to light more advanced principles of machine design--not just the basic principles of AC and DC machine behavior * Introduces electrical machine design to neophytes while also being a resource for experienced designers * ...

  13. An improved FEM model for computing transport AC loss in coils made of RABiTS YBCO coated conductors for electric machines

    International Nuclear Information System (INIS)

    Ainslie, Mark D; Yuan Weijia; Flack, Timothy J; Coombs, Timothy A; Rodriguez-Zermeno, Victor M; Hong Zhiyong

    2011-01-01

    AC loss can be a significant problem for any applications that utilize or produce an AC current or magnetic field, such as an electric machine. The authors investigate the electromagnetic properties of high temperature superconductors with a particular focus on the AC loss in superconducting coils made from YBCO coated conductors for use in an all-superconducting electric machine. This paper presents an improved 2D finite element model for the cross-section of such coils, based on the H formulation. The model is used to calculate the transport AC loss of a racetrack-shaped coil using constant and magnetic field-dependent critical current densities, and the inclusion and exclusion of a magnetic substrate, as found in RABiTS (rolling-assisted biaxially textured substrate) YBCO coated conductors. The coil model is based on the superconducting stator coils used in the University of Cambridge EPEC Superconductivity Group's all-superconducting permanent magnet synchronous motor design. To validate the modeling results, the transport AC loss of a stator coil is measured using an electrical method based on inductive compensation by means of a variable mutual inductance. Finally, the implications of the findings on the performance of the motor are discussed.

  14. An improved FEM model for computing transport AC loss in coils made of RABiTS YBCO coated conductors for electric machines

    Energy Technology Data Exchange (ETDEWEB)

    Ainslie, Mark D; Yuan Weijia; Flack, Timothy J; Coombs, Timothy A [Department of Engineering, University of Cambridge, 9 J J Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Rodriguez-Zermeno, Victor M [Department of Mathematics, Technical University of Denmark, Kongens Lyngby 2800 (Denmark); Hong Zhiyong, E-mail: mda36@cam.ac.uk [School of Electronic, Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China)

    2011-04-15

    AC loss can be a significant problem for any applications that utilize or produce an AC current or magnetic field, such as an electric machine. The authors investigate the electromagnetic properties of high temperature superconductors with a particular focus on the AC loss in superconducting coils made from YBCO coated conductors for use in an all-superconducting electric machine. This paper presents an improved 2D finite element model for the cross-section of such coils, based on the H formulation. The model is used to calculate the transport AC loss of a racetrack-shaped coil using constant and magnetic field-dependent critical current densities, and the inclusion and exclusion of a magnetic substrate, as found in RABiTS (rolling-assisted biaxially textured substrate) YBCO coated conductors. The coil model is based on the superconducting stator coils used in the University of Cambridge EPEC Superconductivity Group's all-superconducting permanent magnet synchronous motor design. To validate the modeling results, the transport AC loss of a stator coil is measured using an electrical method based on inductive compensation by means of a variable mutual inductance. Finally, the implications of the findings on the performance of the motor are discussed.

  15. AC/RF Superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, G [Jefferson Lab (United States)

    2014-07-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  16. AC/RF Superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [JLAB

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  17. Development of low AC loss windings for superconducting traction transformer

    International Nuclear Information System (INIS)

    Kamijo, H; Hata, H; Fukumoto, Y; Tomioka, A; Bohno, T; Yamada, H; Ayai, N; Yamasaki, K; Kato, T; Iwakuma, M; Funaki, K

    2010-01-01

    We have been developing a light weight and high efficiency superconducting traction transformer for railway rolling stock. We designed and fabricated a prototype superconducting traction transformer of a floor-mount type for Shinkansen rolling stock in 2004. We performed the type-test, the system-test, and the vibration-test. Consequently, we could verify that the transformer satisfied the requirement almost exactly as initially planned. However, there have been raised some problems to be solved to put superconducting traction transformer into practical use such that AC loss of the superconducting tape must be lower and the capacity of the refrigerator must be larger. Especially it is the most important to reduce the AC loss of superconducting windings for lightweight and high efficiency. The AC loss must be reduced near the theoretical value of superconducting tape with multifilament. In this study, we fabricated and evaluated the Bi2223 tapes as introduced various measures to reduce the AC loss. We confirmed that the AC loss of the narrow type of Bi2223 tapes with twist of filaments is lower, and we fabricated windings of this tape for use in superconducting traction transformer.

  18. Superconducting magnetic systems and electrical machines

    International Nuclear Information System (INIS)

    Glebov, I.A.

    1975-01-01

    The use of superconductors for magnets and electrical machines attracts close attention of designers and scientists. A description is given of an ongoing research program to create superconductive magnetic systems, commutator motors, homopolar machines, topological generators and turbogenerators with superconductive field windings. All the machines are tentative experimental models and serve as a basis for further developments

  19. Ac superconducting articles and a method for their manufacture

    International Nuclear Information System (INIS)

    Meyerhoff, R.W.

    1975-01-01

    A novel ac superconducting article is described comprising a composite structure having a superconducting surface along with a high thermally conductive material wherein the superconducting surface has the desired physical properties, geometrical shape and surface finish produced by the steps of depositing a superconducting layer upon a substrate having a predetermined surface finish and shape which conforms to that of the desired superconducting article, depositing a supporting layer of material on the superconducting layer and removing the substrate, the surface of the superconductor being a replica of the substrate surface. (auth)

  20. Superconducting ac cable

    Science.gov (United States)

    Schmidt, F.

    1980-11-01

    The components of a superconducting 110 kV ac cable for power ratings or = 2000 MVA were developed. The cable design is of the semiflexible type, with a rigid cryogenic envelope containing a flexible hollow coaxial cable core. The cable core consists of spirally wound Nb-A1 composite wires electrically insulated by high pressure polyethylene tape wrappings. A 35 m long single phase test cable with full load terminals rated at 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of this cable design.

  1. Superconducting ac cable

    International Nuclear Information System (INIS)

    Schmidt, F.

    1980-01-01

    The components of a superconducting 110 kV ac cable for power ratings >= 2000 MVA have been developed. The cable design especially considered was of the semiflexible type, with a rigid cryogenic envelope and flexible hollow coaxial cable cores pulled into the former. The cable core consists of spirally wound Nb-Al composite wires and a HDPE-tape wrapped electrical insulation. A 35 m long single phase test cable with full load terminations for 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of our cable design. (orig.) [de

  2. Ac loss measurements on a superconducting transformer for a 25 kA superconducting rectifier

    NARCIS (Netherlands)

    ten Kate, Herman H.J.; Mulders, J.M.; de Reuver, J.L.; van de Klundert, L.J.M.

    1984-01-01

    Ac loss measurements have been performed on a superconducting transformer. The transformer is a part of a 25 kA thermally switched superconducting rectifier operating at a frequency of 0.1 Hz. The loss measurements have been automatized by means of a microcomputer sampling four relevant signals and

  3. AC loss in superconducting tapes and cables

    NARCIS (Netherlands)

    Oomen, M.P.

    2000-01-01

    The present study discusses the AC loss in high-temperature superconductors. Superconducting materials with a relatively high critical temperature were discovered in 1986. They are presently developed for use in large-scale power-engineering devices such as power-transmission cables, transformers

  4. The Effect of the Feedback Controller on Superconducting Tokamak AC Losses + AC-CRPP user manual

    International Nuclear Information System (INIS)

    Schaerz, B.; Bruzzone, P.; Favez, J.Y.; Lister, J.B.; Zapretilina, E.

    2001-11-01

    Superconducting coils in a Tokamak are subject to AC losses when the field transverse to the coil current varies. A simple model to evaluate the AC losses has been derived and benchmarked against a complete model used in the ITER design procedure. The influence of the feedback control strategy on the AC losses is examined using this model. An improved controller is proposed, based on this study. (author)

  5. Development of Nb3Sn AC superconducting wire. Pt. 2

    International Nuclear Information System (INIS)

    Kasahara, Hobun; Torii, Shinji; Akita, Shirabe; Ueda, Kiyotaka; Kubota, Yoji; Yasohama, Kazuhiko; Kobayashi, Hisayasu; Ogasawara, Takeshi.

    1993-01-01

    For the realization of superconducting power apparatus, it is important that the development of highly stable superconducting cables. Nb 3 Sn wire has higher critical temperature than NbTi wire. Therefore, it is possible to make highly stable superconducting wires. In this report, we examine a manufacturing process of Ac Nb 3 Sn wire. This manufacturing process has four times higher critical current density than conventional processes. We have made a 400 kVA class AC coil with React and Wind method. The loss density of this coil was 20MW/m 3 at just before the quench. In this case, the temperature of cable increased about 3.8 K. This means that the Nb 3 Sn coil has a very high stability. (author)

  6. Measuring ac-loss in high temperature superconducting cable-conductors using four probe methods

    DEFF Research Database (Denmark)

    Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten; Olsen, Søren Krüger

    1999-01-01

    Measuring the ac-loss of superconducting cable conductors have many aspects in common with measuring the ac-loss of single superconducting tapes. In a cable conductor all tapes are connected to each other and to the test circuit through normal metal joints in each end. This makes such measurement...

  7. Self-field AC losses in Bi-2223 superconducting tapes

    International Nuclear Information System (INIS)

    Mueller, K. H.; Leslie, K.E.

    1996-01-01

    Full text: The self-field AC loss in Bi-2223 silver sheathed tapes for AC currents of up to 100 A was measured at 77 K and frequencies of 60 Hz and 600 Hz using a lock-in amplifier. The frequency dependence indicated a purely hysteretic loss which can be well described in terms of the critical state model for a flat superconducting strip. The only parameter needed to predict the self-field AC loss is the critical current of the critical state. Because the loss voltage is extremely small compared with the inductive voltage, a very high accuracy of the lock-in amplifier phase setting is required. Unlike in loss measurements on cylindrical superconducting samples, in the case of the tape the measuring circuit leads have to be brought out from the surface forming a loop where the changing magnetic field induces an additional voltage. Only if the loop formed by the leads at the voltage tabs is large enough will the apparent power dissipation approach the real AC loss associated with the length of the sample probed

  8. Application of superconductivity to pulse fields

    International Nuclear Information System (INIS)

    Saito, Shigeo; Suzawa, Chizuru; Ohkura, Kengo; Nagata, Masayuki; Kawashima, Masao

    1984-01-01

    Numerous attempts to apply the superconductive phenomena of zero electrical resistivity to AC (pulsed) magnets in addition to conventional DC magnet fields are being made in the areas of poloidal coils of nuclear fusion, energy storage, rotary machines, and induction for stabilization of electric power systems. In pulsed superconductive magnets, the stability of the superconductivity and the generation of heat due to AC loss are serious problems. Based on the knowledge obtained through the development of various types of superconductors, magnets, cryostats, and other superconductive-related products, Cu-Ni/Cu/Nb-Ti mixed-matrix fine multifilamentary superconductor wire and the stable, low AC loss superconductors used therein, magnets, and FRP cryostats are developed and manufactured. (author)

  9. Ripple Field AC Losses in 10-MW Wind Turbine Generators With a MgB2 Superconducting Field Winding

    DEFF Research Database (Denmark)

    Liu, Dong; Polinder, Henk; Magnusson, Niklas

    2016-01-01

    Superconducting (SC) synchronous generators are proposed as a promising candidate for 10-20-MW direct-drive wind turbines because they can have low weights and small sizes. A common way of designing an SC machine is to use SC wires with high current-carrying capability in the dc field winding...... and the ac armature winding is made with copper conductors. In such generators, the dc field winding is exposed to ac magnetic field ripples due to space harmonics from the armature. In generator design phases, the ac loss caused by these ripple fields needs to be evaluated to avoid local overheating...... and an excessive cooling budget. To determine the applicability of different design solutions in terms of ac losses, this paper estimates the ac loss level of 10-MW wind generator designs employing a MgB2 SC field winding. The effects on ac losses are compared between nonmagnetic and ferromagnetic teeth...

  10. Low AC-Loss Superconducting Cable Technology for Electric Aircraft Propulsion, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The availability of low AC loss magnesium diboride (MgB2) superconducting wires enables much lighter weight superconducting stator coils than with any other metal or...

  11. Superconducting generator technology--an overview

    International Nuclear Information System (INIS)

    Edmonda, J.S.

    1979-01-01

    Application of superconducting technology to field windings of large ac generators provides virtually unlimited field capability without incurring resistive losses in the winding. Several small-scale superconducting generators have been built and tested demonstrating the feasibility of such concepts. For machines of much larger capacity, conceptual designs for 300 Mva and 1200 Mva have been completed. The development of a 300 Mva generator is projected. Designed, engineered and fabricated as a turbo generator, the superconducting machine is to be installed in a power plant, tested and operated in concert with a prime mover, the steam generator and the auxiliary support systems of the power plant. This will provide answers to the viability of operating a superconducting machine and its cryogenic handling systems in a full time, demanding environment. 21 refs

  12. Design and manufacture of a large superconducting homopolar motor (and status of superconducting a.c. generator)

    International Nuclear Information System (INIS)

    Appleton, A.D.

    1983-01-01

    This paper describes the design and manufacture of a large superconducting motor which, in the present time of financial restraints, is continuing at least to the point of having a completed cryostat with its superconducting winding operating with a dedicated helium refrigeration plant. Comments are also made on the superconducting a.c. generator project, although a final decision on the rating of a prototype and the approval of the funding has not yet been made, the selected rating is expected to be between 200 MW and 600 MW

  13. Superconducting Machines at the Technical University of Denmark

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Abrahamsen, Asger Bech; Mijatovic, Nenad

    2011-01-01

    Two high temperature superconducting (HTS) machine prototypes constructed at the Technical University of Denmark are presented. The construction process is presented and the excellent agreement between simulation results and experimental results are presented for one of the prototypes.......Two high temperature superconducting (HTS) machine prototypes constructed at the Technical University of Denmark are presented. The construction process is presented and the excellent agreement between simulation results and experimental results are presented for one of the prototypes....

  14. AC loss in superconducting wires operating in a wind turbine like generator

    DEFF Research Database (Denmark)

    Seiler, Eugen; Zirngibl, Thomas; Mijatovic, Nenad

    2010-01-01

    We have manufactured a small circular superconducting coil impregnated with epoxy fibreglass. The coil was wound from a Bi-2223/Ag superconducting wire and it was tested in liquid nitrogen at 77 K. Current-voltage characteristic and the AC losses of the coil were measured and compared...

  15. Improvement of superconducting cylindrical linear induction motor; Chodendo entokeitan ichiji rinia yudo mota no tokusei kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Kikuma, T.; Tomita, M.; Ishiyama, A. [Waseda Univ., Tokyo (Japan)

    1999-11-10

    For the purpose of we examining the effect of characteristics and ac loss under real machine operating environment of the alternating current superconductivity winding for a realization of the superconductive AC machine vessel, cylindrical shortness first linear guiding motor which used NbTi/CuNi superconducting cable for the primary winding was produced experimentally. The coil number was increased from 6 in 14 this time, and the optimization of the primary current was done, and the improvement on characteristics was attempted. Here, starting torque characteristics, quenching detection protection control circuit are reported. (NEDO)

  16. Measurement of AC electrical characteristics of SSC superconducting dipole magnets

    International Nuclear Information System (INIS)

    Smedley, K.M.; Shafer, R.E.

    1992-01-01

    Experiments were conducted to measure the AC electrical characteristics of SSC superconducting dipole magnets over the frequency range of 0.1 Hz to 10 kHz. A magnet equivalent circuit representing the magnet DC inductance, eddy current losses, coil-to-ground and turn-to-turn capacitance, was synthesized from the experimental data. This magnet equivalent circuit can be used to predict the current ripple distribution along the superconducting magnet string and can provide dynamic information for the design of the collider current regulation loop

  17. Energy-efficient electrical machines by new materials. Superconductivity in large electrical machines

    International Nuclear Information System (INIS)

    Frauenhofer, Joachim; Arndt, Tabea; Grundmann, Joern

    2013-01-01

    The implementation of superconducting materials in high-power electrical machines results in significant advantages regarding efficiency, size and dynamic behavior when compared to conventional machines. The application of HTS (high-temperature superconductors) in electrical machines allows significantly higher power densities to be achieved for synchronous machines. In order to gain experience with the new technology, Siemens carried out a series of development projects. A 400 kW model motor for the verification of a concept for the new technology was followed by a 4000 kV A generator as highspeed machine - as well as a low-speed 4000 kW propeller motor with high torque. The 4000 kVA generator is still employed to carry out long-term tests and to check components. Superconducting machines have significantly lower weight and envelope dimensions compared to conventional machines, and for this reason alone, they utilize resources better. At the same time, operating losses are slashed to about half and the efficiency increases. Beyond this, they set themselves apart as a result of their special features in operation, such as high overload capability, stiff alternating load behavior and low noise. HTS machines provide significant advantages where the reduction of footprint, weight and losses or the improved dynamic behavior results in significant improvements of the overall system. Propeller motors and generators,for ships, offshore plants, in wind turbine and hydroelectric plants and in large power stations are just some examples. HTS machines can therefore play a significant role when it comes to efficiently using resources and energy as well as reducing the CO 2 emissions.

  18. Superconducting Coil Winding Machine Control System

    Energy Technology Data Exchange (ETDEWEB)

    Nogiec, J. M. [Fermilab; Kotelnikov, S. [Fermilab; Makulski, A. [Fermilab; Walbridge, D. [Fermilab; Trombly-Freytag, K. [Fermilab

    2016-10-05

    The Spirex coil winding machine is used at Fermilab to build coils for superconducting magnets. Recently this ma-chine was equipped with a new control system, which al-lows operation from both a computer and a portable remote control unit. This control system is distributed between three layers, implemented on a PC, real-time target, and FPGA, providing respectively HMI, operational logic and direct controls. The system controls motion of all mechan-ical components and regulates the cable tension. Safety is ensured by a failsafe, redundant system.

  19. AC/DC current ratio in a current superimposition variable flux reluctance machine

    Science.gov (United States)

    Kohara, Akira; Hirata, Katsuhiro; Niguchi, Noboru; Takahara, Kazuaki

    2018-05-01

    We have proposed a current superimposition variable flux reluctance machine for traction motors. The torque-speed characteristics of this machine can be controlled by increasing or decreasing the DC current. In this paper, we discuss an AC/DC current ratio in the current superimposition variable flux reluctance machine. The structure and control method are described, and the characteristics are computed using FEA in several AC/DC ratios.

  20. Reducing Conductor Usage in Superconducting Machines by Multiple Power Supplies

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Mijatovic, Nenad; Abrahamsen, Asger Bech

    2013-01-01

    This paper presents and applies a method of reducing the needed amount of superconductor in a superconducting machine by supplying the superconductor from multiple power supplies. The method is presented and validated experimentally in a constructed prototype. Thereafter, a superconducting tape...

  1. Applications and modelling of bulk HTSs in brushless ac machines

    International Nuclear Information System (INIS)

    Barnes, G.J.

    2000-01-01

    The use of high temperature superconducting material in its bulk form for engineering applications is attractive due to the large power densities that can be achieved. In brushless electrical machines, there are essentially four properties that can be exploited; their hysteretic nature, their flux shielding properties, their ability to trap large flux densities and their ability to produce levitation. These properties translate to hysteresis machines, reluctance machines, trapped-field synchronous machines and linear motors respectively. Each one of these machines is addressed separately and computer simulations that reveal the current and field distributions within the machines are used to explain their operation. (author)

  2. Methods, systems and apparatus for controlling operation of two alternating current (AC) machines

    Science.gov (United States)

    Gallegos-Lopez, Gabriel [Torrance, CA; Nagashima, James M [Cerritos, CA; Perisic, Milun [Torrance, CA; Hiti, Silva [Redondo Beach, CA

    2012-02-14

    A system is provided for controlling two AC machines. The system comprises a DC input voltage source that provides a DC input voltage, a voltage boost command control module (VBCCM), a five-phase PWM inverter module coupled to the two AC machines, and a boost converter coupled to the inverter module and the DC input voltage source. The boost converter is designed to supply a new DC input voltage to the inverter module having a value that is greater than or equal to a value of the DC input voltage. The VBCCM generates a boost command signal (BCS) based on modulation indexes from the two AC machines. The BCS controls the boost converter such that the boost converter generates the new DC input voltage in response to the BCS. When the two AC machines require additional voltage that exceeds the DC input voltage required to meet a combined target mechanical power required by the two AC machines, the BCS controls the boost converter to drive the new DC input voltage generated by the boost converter to a value greater than the DC input voltage.

  3. A Simple and General Approach to Determination of Self and Mutual Inductances for AC machines

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen

    2011-01-01

    Modelling of AC electrical machines plays an important role in electrical engineering education related to electrical machine design and control. One of the fundamental requirements in AC machine modelling is to derive the self and mutual inductances, which could be position dependant. Theories...... developed so far for inductance determination are often associated with complicated machine magnetic field analysis, which exhibits a difficulty for most students. This paper describes a simple and general approach to the determination of self and mutual inductances of different types of AC machines. A new...... determination are given for a 3-phase, salient-pole synchronous machine, and an induction machine....

  4. First electrical tests on a machine with an AC superconducting stator winding

    International Nuclear Information System (INIS)

    Brunet, Y.; Tixador, P.; Laumond, Y.; Sabrie, J.L.

    1988-01-01

    A three phase superconducting stator winding has been built using a low losses NbTi wire under 50 Hz varying magnetic field and current. It has first been necessary to design an horizontal helium cryostat with fiber-glass composites to avoid the permanent eddy-current losses of the rotating magnetic fields. The liquid helium vessel, containing the armature, is dismountable. The cryostat is 900 mm long and the rotor bore has a diameter of 180 mm. The windings are wounded on five concentric fiber glass cylinders with a thin impregnation of an epoxy film adhesive. The first electrical tests have been performed using a normal iron rotor inside the superconducting stator. No load and permanent tests have been achieved up to a power of 13 kVA. The 18,5 kVA predicted have not been reached because of the present inductor, not yet superconducting

  5. A superconducting homopolar motor and generator—new approaches

    International Nuclear Information System (INIS)

    Fuger, Rene; Matsekh, Arkadiy; Kells, John; Sercombe, D B T; Guina, Ante

    2016-01-01

    Homopolar machines were the first continuously running electromechanical converters ever demonstrated but engineering challenges and the rapid development of AC technology prevented wider commercialisation. Recent developments in superconducting, cryogenic and sliding contact technology together with new areas of application have led to a renewed interest in homopolar machines. Some of the advantages of these machines are ripple free constant torque, pure DC operation, high power-to-weight ratio and that rotating magnets or coils are not required. In this paper we present our unique approach to high power and high torque homopolar electromagnetic turbines using specially designed high field superconducting magnets and liquid metal current collectors. The unique arrangement of the superconducting coils delivers a high static drive field as well as effective shielding for the field critical sliding contacts. The novel use of additional shielding coils reduces weight and stray field of the system. Liquid metal current collectors deliver a low resistance, stable and low maintenance sliding contact by using a thin liquid metal layer that fills a circular channel formed by the moving edge of a rotor and surrounded by a conforming stationary channel of the stator. Both technologies are critical to constructing high performance machines. Homopolar machines are pure DC devices that utilise only DC electric and magnetic fields and have no AC losses in the coils or the supporting structure. Guina Energy Technologies has developed, built and tested different motor and generator concepts over the last few years and has combined its experience to develop a new generation of homopolar electromagnetic turbines. This paper summarises the development process, general design parameters and first test results of our high temperature superconducting test motor. (paper)

  6. A superconducting homopolar motor and generator—new approaches

    Science.gov (United States)

    Fuger, Rene; Matsekh, Arkadiy; Kells, John; Sercombe, D. B. T.; Guina, Ante

    2016-03-01

    Homopolar machines were the first continuously running electromechanical converters ever demonstrated but engineering challenges and the rapid development of AC technology prevented wider commercialisation. Recent developments in superconducting, cryogenic and sliding contact technology together with new areas of application have led to a renewed interest in homopolar machines. Some of the advantages of these machines are ripple free constant torque, pure DC operation, high power-to-weight ratio and that rotating magnets or coils are not required. In this paper we present our unique approach to high power and high torque homopolar electromagnetic turbines using specially designed high field superconducting magnets and liquid metal current collectors. The unique arrangement of the superconducting coils delivers a high static drive field as well as effective shielding for the field critical sliding contacts. The novel use of additional shielding coils reduces weight and stray field of the system. Liquid metal current collectors deliver a low resistance, stable and low maintenance sliding contact by using a thin liquid metal layer that fills a circular channel formed by the moving edge of a rotor and surrounded by a conforming stationary channel of the stator. Both technologies are critical to constructing high performance machines. Homopolar machines are pure DC devices that utilise only DC electric and magnetic fields and have no AC losses in the coils or the supporting structure. Guina Energy Technologies has developed, built and tested different motor and generator concepts over the last few years and has combined its experience to develop a new generation of homopolar electromagnetic turbines. This paper summarises the development process, general design parameters and first test results of our high temperature superconducting test motor.

  7. Design and market considerations for axial flux superconducting electric machine design

    Science.gov (United States)

    Ainslie, M. D.; George, A.; Shaw, R.; Dawson, L.; Winfield, A.; Steketee, M.; Stockley, S.

    2014-05-01

    In this paper, the authors investigate a number of design and market considerations for an axial flux superconducting electric machine design that uses high temperature superconductors. The axial flux machine design is assumed to utilise high temperature superconductors in both wire (stator winding) and bulk (rotor field) forms, to operate over a temperature range of 65-77 K, and to have a power output in the range from 10s of kW up to 1 MW (typical for axial flux machines), with approximately 2-3 T as the peak trapped field in the bulk superconductors. The authors firstly investigate the applicability of this type of machine as a generator in small- and medium-sized wind turbines, including the current and forecasted market and pricing for conventional turbines. Next, a study is also carried out on the machine's applicability as an in-wheel hub motor for electric vehicles. Some recommendations for future applications are made based on the outcome of these two studies. Finally, the cost of YBCO-based superconducting (2G HTS) wire is analysed with respect to competing wire technologies and compared with current conventional material costs and current wire costs for both 1G and 2G HTS are still too great to be economically feasible for such superconducting devices.

  8. Reviews of large superconducting machines: Metallurgy, fabrication, and applications

    International Nuclear Information System (INIS)

    Bogner, G.

    1981-01-01

    This paper reviews large superconducting machines presently in place or in experiment. The ''Cello'' particle detector magnet for the positron-electron colliding beam facility PETRA at DESY in Hamburg is shown, and the Fermi Lab, and the Brookhaven ISABELLE also described. Electrodynamic levitation systems are specified, as researched and developed in Germany and Japan. Of superconducting coils for magnetic separation, a high gradient magnetic separator with superconducting magnet and steel wool, and a Jones type high gradient magnetic separator are schematicized. Turbogenerators with superconductor field winding are studied. Superconducting high power cables include the flexible coaxial cable core consisting of a perforated polyethylene tube and test cables at Siemens and at Brookhaven. Magnet systems for fusion reactors include tokamaks and tandem mirrors, and the toroidal coil experiment at Oak Ridge National Laboratory is described, among others. Superconducting magnets for MHD plants, and superconducting magnet energy storage (SME storage) are also discussed

  9. Device for delivering cryogen to rotary super-conducting winding of cryogen-cooled electrical machine

    International Nuclear Information System (INIS)

    Filippov, I.F.; Gorbunov, G.S.; Khutoretsky, G.M.; Popov, J.S.; Skachkov, J.V.; Vinokurov, A.A.

    1980-01-01

    A device is disclosed for delivering cryogen to a superconducting winding of a cryogen-cooled electrical machine comprising a pipe articulated along the axis of the electrical machine and intended to deliver cryogen. One end of said pipe is located in a rotary chamber which communicates through channels with the space of the electrical machine, and said space accommodating its superconducting winding. The said chamber accommodates a needle installed along the chamber axis, and the length of said needle is of sufficient length such that in the advanced position of said cryogen delivering pipe said needle reaches the end of the pipe. The layout of the electrical machine increases the reliability and effectiveness of the device for delivering cryogen to the superconducting winding, simplifies the design of the device and raises the efficiency of the electrical machine

  10. Effect of reduction of mechanical losses in AC superconducting coils having various FRP bobbins

    International Nuclear Information System (INIS)

    Sekine, N.; Tada, S.; Higuchi, T.; Takao, T.; Yamanaka, A.; Fukui, S.

    2004-01-01

    We have demonstrated in our previous works that a use of the particular structural material for superconducting coils was effective to mechanical-loss reduction under AC operation. In this study, we measured losses to investigate influence of the mechanical losses in the coils having various fiber reinforced plastics (FRPs) with different thermal expansion coefficients. The losses were small in the coils whose winding tension at coil-operating temperature were strong, on the contrary, the losses of the coil having the weak winding tension were large. The coil having the strongest winding tension at liquid helium temperature showed the smallest loss in all coils, and the loss agreed with a value from the Norris's analysis. We think that the mechanical loss becomes almost zero in this coil since the strong tension can prevent the periodic vibration of the superconducting wire. The dependence of the loss on the difference in surface conditions of the materials of the superconducting coil's bobbins was not observed, however, the mechanical losses in AC coils strongly depended on the winding tensions at cryogenic temperature

  11. AC loss measurement of superconducting dipole magnets by the calorimetric method

    International Nuclear Information System (INIS)

    Morita, Y.; Hara, K.; Higashi, N.; Kabe, A.

    1996-01-01

    AC losses of superconducting dipole magnets were measured by the calorimetric method. The magnets were model dipole magnets designed for the SSC. These were fabricated at KEK with 50-mm aperture and 1.3-m overall length. The magnet was set in a helium cryostat and cooled down to 1.8 K with 130 L of pressurized superfluid helium. Heat dissipated by the magnet during ramp cycles was measured by temperature rise of the superfluid helium. Heat leakage into the helium cryostat was 1.6 W and was subtracted from the measured heat to obtain AC loss of the magnet. An electrical measurement was carried out for calibration. Results of the two methods agreed within the experimental accuracy. The authors present the helium cryostat and measurement system in detail, and discuss the results of AC loss measurement

  12. The Effect of Temperature Dependence of AC Losses in a Bi-2223/Ag Insert of an 8-T Superconducting Magnet

    DEFF Research Database (Denmark)

    Wang, Lei; Wang, Qiuliang; Wang, Hui

    2016-01-01

    A conduction-cooled split-gap superconducting magnet system with a center field of 8 T has been designed and fabricated in the Institute of Electrical Engineering, Chinese Academy of Sciences. The system consists of two Bi-2223/Ag coils and six NbTi coils. Due to a large aspect ratio of the high-...... in the second case. Hence, it is a good way to reduce the ac losses by changing the charging sequences of the Bi-2223/Ag and NbTi cols. Afterward, the calculated results are compared with the experimental data, and they show a good agreement.......A conduction-cooled split-gap superconducting magnet system with a center field of 8 T has been designed and fabricated in the Institute of Electrical Engineering, Chinese Academy of Sciences. The system consists of two Bi-2223/Ag coils and six NbTi coils. Due to a large aspect ratio of the high......-temperature superconducting tape, there will be large ac losses when the magnet is ramped up and down. An accurate estimation of the total ac losses in the high-temperature superconducting coils is essential for the cryogenic system design. In the Bi-2223/Ag coils, the total ac losses mainly originate from two parts: One...

  13. Study on the adjustment capability of the excitation system located inside superconducting machine electromagnetic shield

    Science.gov (United States)

    Xia, D.; Xia, Z.

    2017-12-01

    The ability for the excitation system to adjust quickly plays a very important role in maintaining the normal operation of superconducting machines and power systems. However, the eddy currents in the electromagnetic shield of superconducting machines hinder the exciting magnetic field change and weaken the adjustment capability of the excitation system. To analyze this problem, a finite element calculation model for the transient electromagnetic field with moving parts is established. The effects of three different electromagnetic shields on the exciting magnetic field are analyzed using finite element method. The results show that the electromagnetic shield hinders the field changes significantly, the better its conductivity, the greater the effect on the superconducting machine excitation.

  14. AC loss in the superconducting cables of the CERN Fast Cycled Magnet Prototype

    NARCIS (Netherlands)

    Borgnolutti, F.; Bottura, L.; Nijhuis, Arend; Zhou, Chao; Liu, Bo; Miyoshi, Y.; Krooshoop, Hendrikus J.G.; Richter, D.

    2011-01-01

    Fast Cycled Superconducting Magnets (FCM's) are an option of interest for the long-term consolidation and upgrade plan of the LHC accelerator complex. The economical advantage of FCM's in the range of 2 T bore field, continuously cycled at 0.5 Hz repetition rate, depends critically on the AC loss

  15. Machine Imperfection Studies of the RAON Superconducting Linac

    Science.gov (United States)

    Jeon, D.; Jang, J.-H.; Jin, H.

    2018-05-01

    Studies of the machine imperfections in the RAON superconducting linac (SCL) that employs normal conducting (NC) quadrupoles were done to assess the tolerable error budgets of the machine imperfections that ensure operation of the beam. The studies show that the beam loss requirement is met even before the orbit correction and that the beam loss requirement is met even without the MHB (multi-harmonic buncher) and VE (velocity equalizer) thanks to the RAON's radio-frequency quadrupole (RFQ) design feature. For the low energy section of the linac (SCL3), a comparison is made between the two superconducting linac lattice types: one lattice that employs NC quadrupoles and the other that employs SC solenoids. The studies show that both lattices meet the beam loss requirement after the orbit correction. However, before the orbit correction, the lattice employing SC solenoids does not meet the beam loss requirement and can cause a significant beam loss, while the lattice employing NC quadrupoles meets the requirement. For the lattice employing SC solenoids, care must be taken during the beam commissioning.

  16. A two-dimensional finite element method to calculate the AC loss in superconducting cables, wires and coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Z; Jiang, Y; Pei, R; Coombs, T A [Electronic, Power and Energy Conversion Group, Engineering Department, University of Cambridge, CB2 1PZ (United Kingdom); Ye, L [Department of Electrical Power Engineering, CAU, P. O. Box 210, Beijing 100083 (China); Campbell, A M [Interdisciplinary Research Centre in Superconductivity, University of Cambridge, CB3 0HE (United Kingdom)], E-mail: Zh223@cam.ac.uk

    2008-02-15

    In order to utilize HTS conductors in AC electrical devices, it is very important to be able to understand the characteristics of HTS materials in the AC electromagnetic conditions and give an accurate estimate of the AC loss. A numerical method is proposed in this paper to estimate the AC loss in superconducting conductors including MgB{sub 2} wires and YBCO coated conductors. This method is based on solving a set of partial differential equations in which the magnetic field is used as the state variable to get the current and electric field distributions in the cross sections of the conductors and hence the AC loss can be calculated. This method is used to model a single-element and a multi-element MgB{sub 2} wires. The results demonstrate that the multi-element MgB{sub 2} wire has a lower AC loss than a single-element one when carrying the same current. The model is also used to simulate YBCO coated conductors by simplifying the superconducting thin tape into a one-dimensional region where the thickness of the coated conductor can be ignored. The results show a good agreement with the measurement.

  17. Superconductive AC current limiter

    International Nuclear Information System (INIS)

    Bekhaled, M.

    1987-01-01

    This patent describes an AC current limiter for a power transport line including a power supply circuit and feeding a load circuit via an overload circuit-breaker member. The limiter comprises a transformer having a primary winding connected in series between the power supply circuit and the load circuit and at least one secondary winding of superconductor material contained in a cryogenic enclosure and short-circuited on itself. The leakage reactance of the transformer as seen from the primary winding is low, and the resistance of the at least one secondary winding when in the non-superconducting state and as seen from the primary is much greater than the nominal impedance of the transformer. The improvement whereby the at least one secondary winding of the transformer comprises an active winding in association with a set of auxiliary windings. The set of auxiliary windings is constituted by an even number of series-connected auxiliary windings wound in opposite directions, with the total number of turns in one direction being equal to the total number of turns in the opposite direction, and with the thermal capacity of the secondary winding as a whole being sufficiently high to limit the expansion thereof to a value which remains small during the time it takes the circuit-breaking member to operate

  18. Improvement of the dynamic performance of an AC linear permanent magnet machine

    NARCIS (Netherlands)

    Jansen, J.W.; Lomonova, E.; Vandenput, A.J.A.; Compter, J.C.; Verweij, A.H.

    2003-01-01

    This paper discusses the controller design and test approaches leading to the performance improvement of a brushless 3-phase AC synchronous permanent magnet linear machine. The feasible controller design concept for the linear machine is presented and further implemented in Simulink and dSPACE. Two

  19. Bearingless AC Homopolar Machine Design and Control for Distributed Flywheel Energy Storage

    Science.gov (United States)

    Severson, Eric Loren

    The increasing ownership of electric vehicles, in-home solar and wind generation, and wider penetration of renewable energies onto the power grid has created a need for grid-based energy storage to provide energy-neutral services. These services include frequency regulation, which requires short response-times, high power ramping capabilities, and several charge cycles over the course of one day; and diurnal load-/generation-following services to offset the inherent mismatch between renewable generation and the power grid's load profile, which requires low self-discharge so that a reasonable efficiency is obtained over a 24 hour storage interval. To realize the maximum benefits of energy storage, the technology should be modular and have minimum geographic constraints, so that it is easily scalable according to local demands. Furthermore, the technology must be economically viable to participate in the energy markets. There is currently no storage technology that is able to simultaneously meet all of these needs. This dissertation focuses on developing a new energy storage device based on flywheel technology to meet these needs. It is shown that the bearingless ac homopolar machine can be used to overcome key obstacles in flywheel technology, namely: unacceptable self-discharge and overall system cost and complexity. Bearingless machines combine the functionality of a magnetic bearing and a motor/generator into a single electromechanical device. Design of these machines is particularly challenging due to cross-coupling effects and trade-offs between motor and magnetic bearing capabilities. The bearingless ac homopolar machine adds to these design challenges due to its 3D flux paths requiring computationally expensive 3D finite element analysis. At the time this dissertation was started, bearingless ac homopolar machines were a highly immature technology. This dissertation advances the state-of-the-art of these machines through research contributions in the areas of

  20. Measurement of AC losses in superconducting tapes by reproduction of thermometric dynamic response

    Energy Technology Data Exchange (ETDEWEB)

    Ligneris, Benoit des; Aubin, Marcel; Cave, Julian

    2003-04-15

    We have developed a dynamic response thermometric method for the measurement of AC losses in high T{sub c} superconductors. This method is based on the comparison of a temperature response caused by a known dissipation in the sample with that produced by the AC losses. By passing a DC current and measuring the DC voltage and corresponding temperature response the sample can be used as its own power dissipation reference. The advantages of this method are the short measurement duration time and the possibility to vary many experimental conditions: for example, AC and DC transport currents and AC, DC and rotating applied magnetic fields. In this article we present the basic method using variable short pulses of constant DC current for calibration and similarly of constant amplitude AC current to create the losses. The losses are obtained by numerical modelling and comparison of the thermometric dynamic response in the two above conditions. Finally, we present some experimental results for a Bi2223 superconducting tape at 50 Hz and 77 K.

  1. The decay properties of the trapped magnetic field in HTS bulk superconducting actuator by AC controlled magnetic field

    International Nuclear Information System (INIS)

    Kim, S.B.; Uwani, Y.; Joo, J.H.; Kawamoto, R.; Jo, Y.S.

    2011-01-01

    The electric device applications of a high temperature superconducting (HTS) bulk magnet, having stable levitation and suspension properties according to their strong flux pinning force, have been proposed and developed. We have been investigating a three-dimensional (3-D) superconducting actuator using HTS bulks to develop a non-contract transportation device which moves freely in space. It is certain for our proposed 3-D superconducting actuator to be useful as a transporter used in a clean room where silicon wafers, which do not like mechanical contact and dust, are manufactured. The proposed actuator consists of the trapped HTS bulk as a mover and two-dimensionally arranged electromagnets as a stator. Up to now, the electromagnets consisted with iron core and copper coil were used as a stator, and each electromagnet was individually controlled using DC power supplies. In our previous work, the unstable movement characteristics of HTS bulk were observed under the DC operation, and the AC electromagnets driven with AC controlled current was proposed to solve these problems. In general, the trapped magnetic field in HTS bulk was decayed by a time-varying external magnetic field. Thus, it needs to optimize the shapes of AC electromagnets and operating patterns, the decay properties of the trapped magnetic field in the HTS bulk mover by the AC magnetic field should be cleared. In this paper, the influences of the frequency, the overall operating time, the strength of magnetization field and drive current against the decay of trapped magnetic field were experimentally studied using the fabricated AC electromagnets.

  2. Hybrid superconducting a.c. current limiter extrapolation 63 kV-1 250 A

    Science.gov (United States)

    Tixador, P.; Levêque, J.; Brunet, Y.; Pham, V. D.

    1994-04-01

    Following the developement of a.c. superconducting wires a.c. current superconducting limiters have emerged. These limiters limit the fault currents nearly instantaneously, without detection nor order giver and may be suitable for high voltages. They are based on the natural transition from the superconducting state to the normal resistive state by overstepping the critical current of a superconducting coil which limits or triggers the limitation. Our limiter device consists essentially of two copper windings coupled through a saturable magnetic circuit and of a non inductively wound superconducting coil with a reduced current compared to the line current. This design allows a simple superconducting cable and reduced cryogenic losses but the dielectric stresses are high during faults. A small model (150 V/50 A) has experimentally validated our design. An industrial scale current limiter is designed and the comparisons between this design and other superconducting current limiters are given. Les courants de court-circuit sur les grands réseaux électriques ne cessent d'augmenter. Dans ce contexte sont apparus les limiteurs supraconducteurs de courant suite au développement des brins supraconducteurs alternatifs. Ces limiteurs peuvent limiter les courants de défaut presque instantanément, sans détection de défaut ni donneur d'ordre et ils sont extrapolables aux hautes tensions. Ils sont fondés sur la transition naturelle de l'état supraconducteur à l'état normal très résistif par dépassement du courant critique d'un enroulement supraconducteur qui limite ou déclenche la limitation. Notre limiteur est composé de deux enroulements en cuivre couplés par un circuit magnétique saturable et d'une bobine supraconductrice à courant réduit par rapport au courant de la ligne. Cette conception permet un câble supraconducteur simple et des pertes cryogéniques réduites mais les contraintes diélectriques en régime de défaut sont importantes. Une maquette

  3. The circular form of the linear superconducting machine for marine propulsion

    Science.gov (United States)

    Rakels, J. H.; Mahtani, J. L.; Rhodes, R. G.

    1981-01-01

    The superconducting linear synchronous machine (LSM) is an efficient method of propulsion of advanced ground transport systems and can also be used in marine engineering for the propulsion of large commercial vessels, tankers, and military ships. It provides high torque at low shaft speeds and ease of reversibility; a circular LSM design is proposed as a drive motor. The equipment is compared with the superconducting homopolar motors, showing flexibility in design, built in redundancy features, and reliability.

  4. 3D Magnetic field modeling of a new superconducting synchronous machine using reluctance network method

    Science.gov (United States)

    Kelouaz, Moussa; Ouazir, Youcef; Hadjout, Larbi; Mezani, Smail; Lubin, Thiery; Berger, Kévin; Lévêque, Jean

    2018-05-01

    In this paper a new superconducting inductor topology intended for synchronous machine is presented. The studied machine has a standard 3-phase armature and a new kind of 2-poles inductor (claw-pole structure) excited by two coaxial superconducting coils. The air-gap spatial variation of the radial flux density is obtained by inserting a superconducting bulk, which deviates the magnetic field due to the coils. The complex geometry of this inductor usually needs 3D finite elements (FEM) for its analysis. However, to avoid a long computational time inherent to 3D FEM, we propose in this work an alternative modeling, which uses a 3D meshed reluctance network. The results obtained with the developed model are compared to 3D FEM computations as well as to measurements carried out on a laboratory prototype. Finally, a 3D FEM study of the shielding properties of the superconducting screen demonstrates the suitability of using a diamagnetic-like model of the superconducting screen.

  5. Development of electric machines with superconducting windings

    International Nuclear Information System (INIS)

    Glebov, I.A.; Novitskij, V.G.

    1977-01-01

    Some studies are discussed performed in the USSR with the aim to develop the most promising electrical machines with superconducting windings, i.e. powerful (more than 1 MW) cryoturbogenerators for power heat and nuclear plants, electric motors of more than 10,000 kW, reverse systems of an electric driver and unipolar generators for electrolysis industry. The design and performances of the simulator of a 1500 kW cryoturbogenerator are given. Problems of coooling and oscillations of the simulator rotor are considered

  6. Achievement report for fiscal 1999 on New Sunshine Program. Frontier research and development of basic superconductive AC power generation equipment; 1999 nendo koryu chodendo denryoku kiki kiban sendo kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    As part of the New Sunshine Program of the Agency of Industrial Science and Technology, a 2-year survey and research is conducted beginning in 1998 on the effect of the introduction of superconductive power equipment for the facilitation of the progress of research and development of basic power equipment which utilizes AC (alternating current) superconductivity. Frontier research and development has been started of basic AC superconductive power equipment for clarifying the tasks to solve in the development effort and for preparing an efficient research and development plan. This fiscal year's endeavor covers the survey of the effect of the introduction of superconductive power equipment in addition to the preparation of a basic plan for the research and development of basic AC superconductive power equipment for fiscal 2000 and afterward, continued survey of research and development trends in and outside Japan for the review of the result achieved in the preceding fiscal year, development of AC equipment element technologies utilizing conduit type semiconductors as a basic study for the embodiment of AC superconductive equipment, and a study for elucidating the mechanism of resistance generated in a superconductive current limiter. Furthermore, papers on the superconduction technology released so far are investigated, and technology development trends and efficient research techniques are put together into a technological information database. (NEDO)

  7. Achievement report for fiscal 1999 on New Sunshine Program. Frontier research and development of basic superconductive AC power generation equipment; 1999 nendo koryu chodendo denryoku kiki kiban sendo kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    As part of the New Sunshine Program of the Agency of Industrial Science and Technology, a 2-year survey and research is conducted beginning in 1998 on the effect of the introduction of superconductive power equipment for the facilitation of the progress of research and development of basic power equipment which utilizes AC (alternating current) superconductivity. Frontier research and development has been started of basic AC superconductive power equipment for clarifying the tasks to solve in the development effort and for preparing an efficient research and development plan. This fiscal year's endeavor covers the survey of the effect of the introduction of superconductive power equipment in addition to the preparation of a basic plan for the research and development of basic AC superconductive power equipment for fiscal 2000 and afterward, continued survey of research and development trends in and outside Japan for the review of the result achieved in the preceding fiscal year, development of AC equipment element technologies utilizing conduit type semiconductors as a basic study for the embodiment of AC superconductive equipment, and a study for elucidating the mechanism of resistance generated in a superconductive current limiter. Furthermore, papers on the superconduction technology released so far are investigated, and technology development trends and efficient research techniques are put together into a technological information database. (NEDO)

  8. Theoretical analysis on ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands

    CERN Document Server

    Iwakuma, M; Funaki, K

    2002-01-01

    The ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands were theoretically investigated. The constituent strands generally need to be insulated and transposed for the sake of uniform current distribution and low ac loss. In case the transposition points deviate from the optimum ones, shielding current is induced according to the interlinkage magnetic flux of the twisted loop enclosed by the insulated strands and the contact resistances at the terminals. It produces an additional ac loss. Supposing a simple situation where a two-strand parallel conductor with one-point transposition is exposed to a uniform ac magnetic field, the basic equations for the magnetic field were proposed and the theoretical expressions of the additional ac losses derived. As a result, the following features were shown. The additional ac loss in the non-saturation case, where the induced shielding current is less than the critical current of a strand, is proportional to the square ...

  9. Electrical Quality Assurance of the Superconducting Circuits during LHC Machine Assembly

    CERN Document Server

    Bozzini, D; Desebe, O; Mess, K H; Russenschuck, Stephan; Bednarek, M; Dworak, D; Górnicki, E; Jurkiewicz, P; Kapusta, P; Kotarba, A; Ludwin, J; Olek, S; Talach, M; Zieblinski, M; Klisch, M; Prochal, B

    2008-01-01

    Based on the LHC powering reference database, all-together 1750 superconducting circuits were connected in the various cryogenic transfer lines of the LHC machine. Testing the continuity, magnet polarity, and the quality of the electrical insulation were the main tasks of the Electrical Quality Assurance (ELQA) activities during the LHC machine assembly. With the assembly of the LHC now complete, the paper reviews the work flow, resources, and the qualification results including the different types of electrical non-conformities.

  10. Experimental apparatus and its operational characteristics for MHD rotating machine with superconducting rotor

    International Nuclear Information System (INIS)

    Katsurai, Makoto; Karasaki, Takashi; Sekiguchi, Tadashi; Matsuda, Shoji; Ichikawa, Hayao.

    1976-01-01

    This paper presents the construction and operational characteristics of the experimental apparatus of MHD rotating machine with superconducting rotor, which has the electromechanical energy conversion function based on the inductive interactions between travelling magnetic field produced by the rotor and MHD working fluid. The machine consists of a rotating-dewar type superconducting rotor and a coaxially rotating metal cylinder which simulates the liquid metal MHD working fluid, and the both of them are driven separately by speed-controlled driving motors. The superconducting magnets installed in the rotor has the 8 shaped winding whose outer diameter is 11 cm and hight is 11 cm, and with the excitation current of 200 A (rating), it produces screw type magnetic field in the inductive interaction region of the cylinder with the peak value of 0.2 Wb/m 2 , whereas the average field strength reaches almost 4 Wb/m 2 inside the winding. In this condition, mutual interaction force is 30 N in the peripheral direction and 8 N in the axial direction and the total driving power of motors is 1,300 W when the relative rotation speed of the rotor and the cylinder is 800 rpm. Observed characteristics of this machine are for the most part in agreement with those estimated by the theoretical analysis. (auth.)

  11. Development of superconducting links for the Large Hadron Collider machine

    Science.gov (United States)

    Ballarino, Amalia

    2014-04-01

    In the framework of the upgrade of the Large Hadron Collider (LHC) machine, new superconducting lines are being developed for the feeding of the LHC magnets. The proposed electrical layout envisages the location of the power converters in surface buildings, and the transfer of the current from the surface to the LHC tunnel, where the magnets are located, via superconducting links containing tens of cables feeding different circuits and transferring altogether more than 150 kA. Depending on the location, the links will have a length ranging from 300 m to 500 m, and they will span a vertical distance of about 80 m. An overview of the R&D program that has been launched by CERN is presented, with special attention to the development of novel types of cables made from MgB2 and high temperature superconductors (Bi-2223 and REBCO) and to the results of the tests performed on prototype links. Plans for future activities are presented, together with a timeline for potential future integration in the LHC machine.

  12. Development of superconducting links for the Large Hadron Collider machine

    CERN Document Server

    Ballarino, A

    2014-01-01

    In the framework of the upgrade of the Large Hadron Collider (LHC) machine, new superconducting lines are being developed for the feeding of the LHC magnets. The proposed electrical layout envisages the location of the power converters in surface buildings, and the transfer of the current from the surface to the LHC tunnel, where the magnets are located, via superconducting links containing tens of cables feeding different circuits and transferring altogether more than 150 kA. Depending on the location, the links will have a length ranging from 300 m to 500 m, and they will span a vertical distance of about 80 m. An overview of the R&D program that has been launched by CERN is presented, with special attention to the development of novel types of cables made from MgB 2 and high temperature superconductors (Bi-2223 and REBCO) and to the results of the tests performed on prototype links. Plans for future activities are presented, together with a timeline for potential future integration in the LHC machine.

  13. A control system for and a method of controlling a superconductive rotating electrical machine

    DEFF Research Database (Denmark)

    2014-01-01

    This invention relates to a method of controlling and a control system (100) for a superconductive rotating electric machine (200) comprising at least one superconductive winding (102; 103), where the control system (100) is adapted to control a power unit (101) supplying during use the at least...... or more actual values (110, 111)of one or more parameters for a given superconductive winding (102; 103), each parameter representing a physical condition of the given superconductive winding (102; 103), and to dynamically derive one or more electrical current values to be maintained in the given...... superconductive winding (102; 103) by the power unit (101) where the one or more electrical current values is/are derived taking into account the received one or more actual values (110, 111). In this way,greater flexibility and more precise control of the performance of the superconducting rotating electrical...

  14. A numerical method to estimate AC loss in superconducting coated conductors by finite element modelling

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Z; Jiang, Q; Pei, R; Campbell, A M; Coombs, T A [Engineering Department, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2007-04-15

    A finite element method code based on the critical state model is proposed to solve the AC loss problem in YBCO coated conductors. This numerical method is based on a set of partial differential equations (PDEs) in which the magnetic field is used as the state variable. The AC loss problems have been investigated both in self-field condition and external field condition. Two numerical approaches have been introduced: the first model is configured on the cross-section plane of the YBCO tape to simulate an infinitely long superconducting tape. The second model represents the plane of the critical current flowing and is able to simulate the YBCO tape with finite length where the end effect is accounted. An AC loss measurement has been done to verify the numerical results and shows a good agreement with the numerical solution.

  15. Computer control system of the superconducting SR-light source ''Aurora''

    International Nuclear Information System (INIS)

    Yamada, H.

    1989-01-01

    The Aurora is a compact SR-light system optimized for x-ray lithography. The system includes a superconducting electron storage ring, a 150-MeV race track microtron as an injector, and light beamlines. The SR-ring features a single magnet body, in which the 650-MeV electron beam orbits a true circular trajectory of 1 m diameter. The computer control system developed for Aurora has a three-level hierarchical architecture. The top level is the Central Intelligence System, and the second an Autonomic Control System (ACS). The bottom is an assembly of distributed local controllers linked to the ACS level through optical fibers. This system provides fully automatic and remote operation, and a powerful machine study capability through the associated man--machine console and the interpretive operation language

  16. Computer control system of the superconducting SR-light source ``Aurora''

    Science.gov (United States)

    Yamada, Hironari

    1989-07-01

    The Aurora is a compact SR-light system optimized for x-ray lithography. The system includes a superconducting electron storage ring, a 150-MeV race track microtron as an injector, and light beamlines. The SR-ring features a single magnet body, in which the 650-MeV electron beam orbits a true circular trajectory of 1 m diameter. The computer control system developed for Aurora has a three-level hierarchical architecture. The top level is the Central Intelligence System, and the second an Autonomic Control System (ACS). The bottom is an assembly of distributed local controllers linked to the ACS level through optical fibers. This system provides fully automatic and remote operation, and a powerful machine study capability through the associated man-machine console and the interpretive operation language.

  17. Studies on Nb3Sn field coils for superconducting machine

    International Nuclear Information System (INIS)

    Fujino, H.; Nose, S.

    1981-01-01

    This paper describes experimental studies on several coils wound with multifilamentary (MF) Nb 3 Sn cables with reinforcing strip for superconducting rotating machine application. To use a Nb 3 Sn superconductor to field winding of a rotating machine, several coil performances of pre-reacted, bronze processed and stranded MF Nb 3 Sn cables were investigated, mainly in relation to stress effect. Bending strain up to 0.64% in strand and winding stress of 5 kg/mm 2 have resulted in nondegradation in coil performance. A pair of impregnated race-track coils designed for a 30 MVA synchronous condenser was energized successfully up to 80% of critical current without quench. 8 refs

  18. Study of the AC machines winding having fractional q

    Science.gov (United States)

    Bespalov, V. Y.; Sidorov, A. O.

    2018-02-01

    The winding schemes with a fractional numbers of slots per pole and phase q have been known and used for a long time. However, in the literature on the low-noise machines design there are not recommended to use. Nevertheless, fractional q windings have been realized in many applications of special AC electrical machines, allowing to improve their performance, including vibroacoustic one. This paper deals with harmonic analysis of windings having integer and fractional q in permanent magnet synchronous motors, a comparison of their characteristics is performed, frequencies of subharmonics are revealed. Optimal winding pitch design is found giving reduce the amplitudes of subharmonics. Distribution factors for subharmonics, fractional and high-order harmonics are calculated, results analysis is represented, allowing for giving recommendations how to calculate distribution factors for different harmonics when q is fractional.

  19. An experimental study on a superconducting generator with dual machine shield system

    International Nuclear Information System (INIS)

    Ishigohka, T.; Ninomiya, A.; Okada, T.; Nitta, T.; Shintani, T.; Mukai, E.

    1988-01-01

    The authors have studied the optimal machine shield system through experiments on a 20kVa superconducting generator. The first experiment is carried out on a fully iron-less aluminum-shield machine which has only an aluminum eddy current machine shield in the stator. The second experiment is carried out on a generator with a dual-shield system which has both an aluminum eddy current shield and an iron magnetic shield. From the first one, the authors have got an experimental result that the aluminum-shield machine exhibits so large eddy current loss in the shield that it would be difficult to operate the machine continuously. On the other hand, the second experiment shows that the dual-shield machine exhibits much smaller loss in the shielding system, and that it has higher output power than the aluminum-shield machine. From these experiments, it becomes clear that insertion of a very thin iron shield between the armature winding and the eddy current shield can improve the machine performance eminently without large weight increase even if the iron shield were saturated

  20. Vector control of three-phase AC machines system development in the practice

    CERN Document Server

    Quang, Nguyen Phung; Dittrich, J

    2015-01-01

    This book addresses the vector control of three-phase AC machines, in particular induction motors with squirrel-cage rotors (IM), permanent magnet synchronous motors (PMSM) and doubly-fed induction machines (DFIM), from a practical design and development perspective. The main focus is on the application of IM and PMSM in electrical drive systems, where field-orientated control has been successfully established in practice. It also discusses the use of grid-voltage oriented control of DFIMs in wind power plants. This second, enlarged edition includes new insights into flatness-based  nonlinear

  1. Energy-efficient electrical machines by new materials. Superconductivity in large electrical machines; Energieeffiziente elektrische Maschinen durch neue Materialien. Supraleitung in grossen elektrischen Maschinen

    Energy Technology Data Exchange (ETDEWEB)

    Frauenhofer, Joachim [Siemens, Nuernberg (Germany); Arndt, Tabea; Grundmann, Joern [Siemens, Erlangen (Germany)

    2013-07-01

    The implementation of superconducting materials in high-power electrical machines results in significant advantages regarding efficiency, size and dynamic behavior when compared to conventional machines. The application of HTS (high-temperature superconductors) in electrical machines allows significantly higher power densities to be achieved for synchronous machines. In order to gain experience with the new technology, Siemens carried out a series of development projects. A 400 kW model motor for the verification of a concept for the new technology was followed by a 4000 kV A generator as highspeed machine - as well as a low-speed 4000 kW propeller motor with high torque. The 4000 kVA generator is still employed to carry out long-term tests and to check components. Superconducting machines have significantly lower weight and envelope dimensions compared to conventional machines, and for this reason alone, they utilize resources better. At the same time, operating losses are slashed to about half and the efficiency increases. Beyond this, they set themselves apart as a result of their special features in operation, such as high overload capability, stiff alternating load behavior and low noise. HTS machines provide significant advantages where the reduction of footprint, weight and losses or the improved dynamic behavior results in significant improvements of the overall system. Propeller motors and generators,for ships, offshore plants, in wind turbine and hydroelectric plants and in large power stations are just some examples. HTS machines can therefore play a significant role when it comes to efficiently using resources and energy as well as reducing the CO{sub 2} emissions.

  2. AC machine control : robust and sensorless control by parameter independency

    Energy Technology Data Exchange (ETDEWEB)

    Samuelsen, Dag Andreas Hals

    2009-06-15

    In this thesis it is first presented how robust control can be used to give AC motor drive systems competitive dynamic performance under parameter variations. These variations are common to all AC machines, and are a result of temperature change in the machine, and imperfect machine models. This robust control is, however, dependent on sensor operation in the sense that the rotor position is needed in the control loop. Elimination of this control loop has been for many years, and still is, a main research area of AC machines control systems. An integrated PWM modulator and sampler unit has been developed and tested. The sampler unit is able to give current and voltage measurements with a reduced noise component. It is further used to give the true derivative of currents and voltages in the machine and the power converter, as an average over a PWM period, and as separate values for all states of the power converter. In this way, it can give measurements of the currents as well as the derivative of the currents, at the start and at the end of a single power inverter state. This gave a large degree of freedom in parameter and state identification during uninterrupted operation of the induction machine. The special measurement scheme of the system achieved three main goals: By avoiding the time frame where the transistors commutate and the noise in the measurement of the current is large, filtering of the current measurement is no longer needed. The true derivative of the current in the machine is can be measured with far less noise components. This was extended to give any separate derivative in all three switching states of the power converter. Using the computational resources of the FPGA, more advanced information was supplied to the control system, in order to facilitate sensor less operation, with low computational demands on the DSP. As shown in the papers, this extra information was first used to estimate some of the states of the machine, in some or all of the

  3. Nb46, 5wt% Ti Eb-melting for AC and DC superconducting applications

    International Nuclear Information System (INIS)

    Bormio, C.; Ramos, M.J.; Pinatti, D.G.

    1990-01-01

    This paper reports on the superconductor alloy Nb46, 5wt % Ti which presents the best superconducting and mechanical properties for the systems Nb-Ti. The greatest difficulty in obtaining this alloy is related to the difference between the raw materials melting temperatures, which is about 700 degrees C. As a result the alloy homogeneity as well as Ti desired content, turn to be hard to control. The authors choose an electrode sandwich type, where Nb and Ti sheets are interposed. The electrode dimensions calculation is based on the Ti evaporation rate, energy balance and superficial tension of liquid titanium between Nb sheets. The ingots were electron beam melted. Herein, we present the following ingot results: Ti, intersticial and trace contents compared to international manufactures as well as its mechanical workability. This alloy will be used in NbTi wire production for AC and DC applications. The AC and DC wires are produced by coswaging and codrawing of NbTi bars and C u Ni-tubes for AC wires and Cu-tubes for DC wires. High area reductions of about 2 x 10 8 are reached without intermediate heat treatment, and they are essential since they are precursors of collective pinning centers, responsible for high critical current densities

  4. Status of superconducting power transformer development

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.C.; McConnell, B.W.; Mehta, S.P. [and others

    1996-03-01

    Development of the superconducting transformer is arguably the most difficult of the ac power applications of superconductivity - this is because of the need for very low ac losses, adequate fault and surge performance, and the rigors of the application environment. This paper briefly summarizes the history of superconducting transformer projects, reviews the key issues for superconducting transformers, and examines the status of HTS transformer development. Both 630-kVA, three-phase and 1-MVA single phase demonstration units are expected to operate in late 1996. Both efforts will further progress toward the development of economical and performance competitive superconducting transformers.

  5. Improvement of superconducting cylindrical linear induction motor; Chodendo entogata tan'ichiji rinia yudo mota no tokusei kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Kikuma, T.; Ishiyama, A. [Waseda Univ., Tokyo (Japan)

    2000-05-29

    For the purpose of examining the characteristics (effect of stability and ac loss by the higher harmonic wave etc.) of an alternating current superconductivity winding under a real machine operating environment of the super-conductive AC machine vessel, authors produced a cylindrical shortness first linear guiding motor (SCLIM) which used the NbTi/CuNi super-conducting cable for the first excitation winding experimentally. In this study, the evaluation of the start up thrust and operation confirmation of the quenching detection protection circuit were carried out using the produced SCLIM. In the quenching detection protection control circuit, the first excitation winding was divided into an internal layer and an outer layer, and both layers were excited in the 2 layer division and a quenching detection protection circuit was installed on the 2 layers respectively. The circuit of a part of fact by this of the phase in which the quench was generated and observed was cut off, and the operation would be able to be continued in part of the remainder of the phase and other two phases. Here, it is to cut off the quenched phase from the circuit, when the phase current becomes zero, and the other effect on the phase is held as small as possible. (NEDO)

  6. Calorimetric method of ac loss measurement in a rotating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Ghoshal, P. K. [Oxford Instruments NanoScience, Abingdon, Oxfordshire OX13 5QX (United Kingdom); Coombs, T. A.; Campbell, A. M. [Department of Engineering, Electrical Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

    2010-07-15

    A method is described for calorimetric ac-loss measurements of high-T{sub c} superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines.

  7. Measurement of ac electrical characteristics of SSC dipole magnets at Brookhaven

    International Nuclear Information System (INIS)

    Smedley, K.

    1992-04-01

    The SSC collider is designed to have circumference of 87 km. The superconducting magnets along the collider ring are grouped into ten sectors. Each sector, a string of average length of 8.7 km,m is powered by one power source located near the center of the sector. Because of the alternating-current (ac) electrical characteristics of the magnets, the power supply ripple currents and transients form a time and space distribution in the magnet string which affects particle motions. Additionally, since the power supply load is a magnet string, the current regulation loop design is highly dependent upon the ac electrical characteristics of the magnets. A means is needed to accurately determine the ac electrical characteristics of the superconducting magnets. The ac characteristics of magnets will be used to predict the ripple distribution of the long string of superconducting magnets. Magnet ac characteristics can also provide necessary information for the regulation loop design. This paper presents a method for measuring the ac characteristics of superconducting magnets. Two collider dipole magnets, one superconducting and one at room temperature, were tested at Brookhaven National Lab

  8. FY 1998 annual report on the leading fundamental research and development of AC superconducting power apparatuses (New Sunshine Project); 1998 nendo koryu chodendo denryoku kiki kiban sendo kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    In order to propose fundamental research and development of AC superconducting power apparatuses, the FY 1998 efforts were directed to studies on the effects of introducing superconducting apparatuses, making proposals of development programs, literature (including patent publications) surveys on trends of research and development at home and abroad, and making proposals for technological breakthroughs. Results of the studies for evaluating economic efficiency of these apparatuses and the effects of their introduction indicate that the promising apparatuses for eventual commercialization include superconducting cables, current limiters, field power generators, transformers and flywheels. The superconducting cables are expected to greatly reduce losses and hence CO2 emissions. The superconducting current limiters are promising means to control short-circuit current increase in the trunk power systems in which they are used. The superconducting transformers are expected to reduce losses and hence CO2 emissions. The project of fundamental research and development of AC superconducting power apparatuses has proposed the fundamental technological research themes aimed at development of the elementary techniques prerequisite for realizing these 3 types of apparatuses and reflection of the required apparatus specifications in development of the cable materials. (NEDO)

  9. Conceptual design of current lead for large scale high temperature superconducting rotating machine

    International Nuclear Information System (INIS)

    Le, T. D.; Kim, J. H.; Park, S. I.; Kim, H. M.

    2014-01-01

    High-temperature superconducting (HTS) rotating machines always require an electric current of from several hundreds to several thousand amperes to be led from outside into cold region of the field coil. Heat losses through the current leads then assume tremendous importance. Consequently, it is necessary to acquire optimal design for the leads which would achieve minimum heat loss during operation of machines for a given electrical current. In this paper, conduction cooled current lead type of 10 MW-Class HTS rotating machine will be chosen, a conceptual design will be discussed and performed relied on the least heat lost estimation between conventional metal lead and partially HTS lead. In addition, steady-state thermal characteristic of each one also is considered and illustrated.

  10. ASC 84: applied superconductivity conference. Final program and abstracts

    International Nuclear Information System (INIS)

    1984-01-01

    Abstracts are given of presentations covering: superconducting device fabrication; applications of rf superconductivity; conductor stability and losses; detectors and signal processing; fusion magnets; A15 and Nb-Ti conductors; stability, losses, and various conductors; SQUID applications; new applications of superconductivity; advanced conductor materials; high energy physics applications of superconductivity; electronic materials and characterization; general superconducting electronics; ac machinery and new applications; digital devices; fusion and other large scale applications; in-situ and powder process conductors; ac applications; synthesis, properties, and characterization of conductors; superconducting microelectronics

  11. ASC 84: applied superconductivity conference. Final program and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    Abstracts are given of presentations covering: superconducting device fabrication; applications of rf superconductivity; conductor stability and losses; detectors and signal processing; fusion magnets; A15 and Nb-Ti conductors; stability, losses, and various conductors; SQUID applications; new applications of superconductivity; advanced conductor materials; high energy physics applications of superconductivity; electronic materials and characterization; general superconducting electronics; ac machinery and new applications; digital devices; fusion and other large scale applications; in-situ and powder process conductors; ac applications; synthesis, properties, and characterization of conductors; superconducting microelectronics. (LEW)

  12. Fault-current limiter using a superconducting coil

    International Nuclear Information System (INIS)

    Boenig, H.J.; Paice, D.A.

    1982-01-01

    A novel circuit, consisting of solid-state diodes and a biased superconducting coil, for limiting the fault currents in three-phase ac systems is presented. A modification of the basic circuit results in a solid-state ac breaker with current-limiting features. The operating characteristics of the fault-current limiter and the ac breaker are analyzed. An optimization procedure for sizing the superconducting coil is derived

  13. Superconducting magnetic energy storage for asynchronous electrical systems

    Science.gov (United States)

    Boenig, Heinrich J.

    1986-01-01

    A superconducting magnetic energy storage coil connected in parallel between converters of two or more ac power systems provides load leveling and stability improvement to any or all of the ac systems. Control is provided to direct the charging and independently the discharging of the superconducting coil to at least a selected one of the ac power systems.

  14. INFLUENCE OF FEEDING ELECTRIC ENERGY QUALITY ON HEATING OF THE AUXILIARY MA-CHINES OF AC ELECTRIC ROLLING STOCK

    Directory of Open Access Journals (Sweden)

    O. YU. Baliichuk

    2014-04-01

    Full Text Available Purpose. The article aims to study the problem of increase the reliability of auxiliary machines for AC electric trains during operation in real conditions. Methodology. The peculiarity of system construction of auxiliary machines for AC electric rolling stock is the use of asynchronous motors for general industrial purpose. An engineering method of influence determination on the feeding voltage asymmetry and its deviation from the nominal value on heating of auxiliary machines insulation was proposed. Findings. It is found out that in case when the auxiliary machines of AC electric trains work under asymmetry factor of the voltage 10% or more and feeding voltage deviation from the nominal order 0.6 relative unit then it is possible the overheat of their isolation, even if it has class H. Originality. For the first time the issue of the total insulation heating under such boundary parameters combinations of energy quality, when each of them contributes to the heating insulation increase as compared to the nominal regime of the "rotating phase splitter−auxiliary machinery" system was illuminated. Practical value. Conducted research allow us to establish the boundary parameter values of feeding energy quality (asymmetry factor, feeding voltage deviations from the nominal value, at which additional isolation overheating of this class under the effect of specified factors will not exceed the agreed value.

  15. Algorithm for determining two-periodic steady-states in AC machines directly in time domain

    Directory of Open Access Journals (Sweden)

    Sobczyk Tadeusz J.

    2016-09-01

    Full Text Available This paper describes an algorithm for finding steady states in AC machines for the cases of their two-periodic nature. The algorithm enables to specify the steady-state solution identified directly in time domain despite of the fact that two-periodic waveforms are not repeated in any finite time interval. The basis for such an algorithm is a discrete differential operator that specifies the temporary values of the derivative of the two-periodic function in the selected set of points on the basis of the values of that function in the same set of points. It allows to develop algebraic equations defining the steady state solution reached in a chosen point set for the nonlinear differential equations describing the AC machines when electrical and mechanical equations should be solved together. That set of those values allows determining the steady state solution at any time instant up to infinity. The algorithm described in this paper is competitive with respect to the one known in literature an approach based on the harmonic balance method operated in frequency domain.

  16. Multipole superconducting electric motors for ship propulsion

    International Nuclear Information System (INIS)

    Thullen, P.; Keim, T.A.; Minervini, J.V.

    1975-01-01

    While a great deal of attention has been paid to two-pole superconducting synchronous machines, very little analysis of low speed, multipole superconducting synchronous machines has been done. Such machines may prove desirable as drive motors in ship drive systems. Results are presented of an analysis which assumes a motor of sufficient size that the airgap may be considered to be flat. A power output expression is given which shows the effects of machine geometry and superconductor characteristics on machine size. Based on this expression, a 40,000 hp 120 rpm motor is sized, and the resulting machine is compared with a conventional ship drive motor. The comparison illustrates possible size reductions through the application of superconductivity

  17. Hydrostatic Pressure Study on 3-K Phase Superconductivity in Sr2RuO4-Ru Eutectic Crystals by AC Magnetic Susceptibility Measurements

    International Nuclear Information System (INIS)

    Yaguchi, Hiroshi; Watanabe, Hiromichi; Sakaue, Akira

    2012-01-01

    We have investigated the effect of hydrostatic pressure on 3-K phase superconductivity in Sr 2 RuO 4 -Ru eutectic crystals by means of AC magnetic susceptibility measurements. We have found that the application of hydrostatic pressure suppresses the superconducting transition temperature T c of the 3-K phase with a pressure coefficient of dT c /dP ≈ −0.2 K/GPa, similar to the case of the 1.5-K phase. We have also observed that the effect of hydrostatic pressure on the 3-K phase seems to be elastic whilst that of uniaxial pressure is plastic.

  18. Machine Control System of Steady State Superconducting Tokamak-1

    Energy Technology Data Exchange (ETDEWEB)

    Masand, Harish, E-mail: harish@ipr.res.in; Kumar, Aveg; Bhandarkar, M.; Mahajan, K.; Gulati, H.; Dhongde, J.; Patel, K.; Chudasma, H.; Pradhan, S.

    2016-11-15

    Highlights: • Central Control System. • SST-1. • Machine Control System. - Abstract: Central Control System (CCS) of the Steady State Superconducting Tokamak-1 (SST-1) controls and monitors around 25 plant and experiment subsystems of SST-1 located remotely from the Central-Control room. Machine Control System (MCS) is a supervisory system that sits on the top of the CCS hierarchy and implements the CCS state diagram. MCS ensures the software interlock between the SST-1 subsystems with the CCS, any subsystem communication failure or its local error does not prohibit the execution of the MCS and in-turn the CCS operation. MCS also periodically monitors the subsystem’s status and their vital process parameters throughout the campaign. It also provides the platform for the Central Control operator to visualize and exchange remotely the operational and experimental configuration parameters with the sub-systems. MCS remains operational 24 × 7 from the commencement to the termination of the SST-1 campaign. The developed MCS has performed robustly and flawlessly during all the last campaigns of SST-1 carried out so far. This paper will describe various aspects of the development of MCS.

  19. Stability Enhancement of Multi machine AC Systems by Synchronverter HVDC control

    Directory of Open Access Journals (Sweden)

    Raouia Aouini

    2016-06-01

    Full Text Available This paper investigates the impact of the Synchronverter based HVDC control on power system stability. The study considers multi machine power systems, with realistic parameters. A specific tuning method of the parameters of the regulators is used. The proposed control scheme is based on the sensitivity of the poles of the HVDC neighbor zone to the control parameters, and next, on their placement using residues. The transient stability of the HVDC neighbor zone is a priori taken into account at the design stage. The new tuning method is evaluated in comparison with the standard vector control via simulation tests. Extensive tests are performed using Matlab/Simulink implementation of the IEEE 9 bus/3 machines test system. The results prove the superiority of the proposed control to the classic vector control. The synchronverter control allows to improve not only the local performances of the HVDC link, but also the overall transient stability of the AC zone in which the HVDC is inserted. (where

  20. A General and Intuitive Approach to Understand and Compare the Torque Production Capability of AC Machines

    DEFF Research Database (Denmark)

    Wang, Dong; Lu, Kaiyuan; Rasmussen, Peter Omand

    2014-01-01

    Electromagnetic torque analysis is one of the key issues in the analysis of electric machines. It plays an important role in machine design and control. The common method described in most of the textbooks is to calculate the torque in the machine variables and then transform them to the dq......-frame, through complicated mathematical manipulations. This is a more mathematical approach rather than explaining the physics behind torque production, which even brings a lot of difficulties to specialist. This paper introduces a general and intuitive approach to obtain the dq-frame torque equation of various...... AC machines. In this method, torque equation can be obtained based on the intuitive physical understanding of the mechanism behind torque production. It is then approved to be applicable for general case, including rotor saliency and various types of magnetomotive force sources. As an application...

  1. An establish attempt of reasons of machining splinter formation in AC44200 alloy high pressure die castings

    OpenAIRE

    J. Mutwil

    2008-01-01

    A problem of splinter formation during machining the AC44200 alloy high pressure die casting has been experimental investigated. Inorder to establish the reason of this occurrence a set of 200 high pressure die casting of the tensile strength samples have been prepared. The tensile tests were carried out using a Zwick Z050 universal testing machine. JM-SPC program has been used for statistical analysis of test results. A large variability of tensile strength results has been found. In order t...

  2. Transient characteristics of current lead losses for the large scale high-temperature superconducting rotating machine

    International Nuclear Information System (INIS)

    Le, T. D.; Kim, J. H.; Park, S. I.; Kim, D. J.; Kim, H. M.; Lee, H. G.; Yoon, Y. S.; Jo, Y. S.; Yoon, K. Y.

    2014-01-01

    To minimize most heat loss of current lead for high-temperature superconducting (HTS) rotating machine, the choice of conductor properties and lead geometry - such as length, cross section, and cooling surface area - are one of the various significant factors must be selected. Therefore, an optimal lead for large scale of HTS rotating machine has presented before. Not let up with these trends, this paper continues to improve of diminishing heat loss for HTS part according to different model. It also determines the simplification conditions for an evaluation of the main flux flow loss and eddy current loss transient characteristics during charging and discharging period.

  3. AC Loss Reduction in Filamentized YBCO Coated Conductors with Virtual Transverse Cross-cuts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yifei [ORNL; Duckworth, Robert C [ORNL; Ha, Tam T [ORNL; List III, Frederick Alyious [ORNL; Gouge, Michael J [ORNL; Chen, Y [SuperPower Incorporated, Schenectady, New York; X, Xiong, [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2011-01-01

    While the performance of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO)-based coated conductors under dc currents has improved significantly in recent years, filamentization is being investigated as a technique to reduce ac loss so that the 2nd generation (2G) high temperature superconducting (HTS) wires can also be utilized in various ac power applications such as cables, transformers and fault current limiters. Experimental studies have shown that simply filamentizing the superconducting layer is not effective enough to reduce ac loss because of incomplete flux penetration in between the filaments as the length of the tape increases. To introduce flux penetration in between the filaments more uniformly and further reduce the ac loss, virtual transverse cross-cuts were made in superconducting filaments of the coated conductors fabricated using the metal organic chemical vapor deposition (MOCVD) method. The virtual transverse cross-cuts were formed by making cross-cuts (17 - 120 {micro}m wide) on the IBAD (ion beam assisted deposition)-MgO templates using laser scribing followed by depositing the superconducting layer ({approx} 0.6 {micro}m thick). AC losses were measured and compared for filamentized conductors with and without the cross-cuts under applied peak ac fields up to 100 mT. The results were analyzed to evaluate the efficacy of filament decoupling and the feasibility of using this method to achieve ac loss reduction.

  4. Development of superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Mijatovic, Nenad; Abrahamsen, Asger Bech

    2013-01-01

    In this paper, the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational...... speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors; one is based on high temperature superconductors......; and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are, however, not without their challenges. The superconductors have to be cooled down to somewhere...

  5. Development of Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Mijatovic, Nenad; Abrahamsen, Asger Bech

    2012-01-01

    In this paper the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational...... speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors (LTS); one is based on high temperature superconductors...... (HTS); and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are however not without their challenges. The superconductors have to be cooled down...

  6. Future development of large superconducting generators

    International Nuclear Information System (INIS)

    Singh, S.K.; Mole, C.J.

    1989-01-01

    Large superconducting generators are being developed worldwide. The use of superconductors to reduce the electrical power dissipation in power equipment has been a technological possibility ever since the discovery of superconductivity, even though their use in power equipment remained an impractical dream for a long time. However, scientific and technological progress in superconductivity and cryogenics has brought this dream much closer to reality. Results obtained so far establish the technical feasibility of these machines. Analytical developments have been providing a sound basis for the design of superconducting machines and results of these design studies have shown improvements in power density of up to a factor of 10 higher than the power density for conventional machines. This paper describes the recently completed USA programs, the current foreign and USA programs, and then proposes a USA development program to maintain leadership in the field

  7. Analysis of a dc commutator machine for exchange of energy with a superconducting coil

    International Nuclear Information System (INIS)

    Vogel, H.F.

    1978-08-01

    A 500-kW dc commutator machine, C, is analyzed for use in an LC circuit with a ringing period of approximately 4 s with a superconducting coil, L. Electrical measurements and the important design equations and characteristics are listed. Attention is paid to the calculation of the commutating voltage, which is an important design feature because it sets a limit to the current allowable in the LC circuit, amounting to 6 times rated machine current. The equations for the energy loss components of the generator are given and fitted to experimental coast-down data. With a fitting accuracy of 1.2%, the loss coefficients for the bearing loss, brush loss, windage loss, and tooth eddy current loss in the remanent stator field are thus determined

  8. Superconducting RF for energy-recovery linacs

    International Nuclear Information System (INIS)

    Liepe, M.; Knobloch, J.

    2006-01-01

    Since superconducting RF for particle accelerators made its first appearance in the 1970s, it has found highly successful application in a variety of machines. Recent progress in this technology has made so-called Energy-Recovery Linacs (ERLs)-originally proposed in 1965-feasible, and interest in this type of machine has increased enormously. A superconducting linac is the driving heart of ERLs, and emittance preservation and cost efficiency is of utmost importance. The resulting challenges for the superconducting cavity technology and RF field control are manifold. In March 2005 the first international workshop on ERLs was held at Newport News, VA, to explore the potential of ERLs and to discuss machine-physics and technology challenges and their solutions. This paper reviews the state-of-the-art in superconducting RF and RF control for ERLs, and summarizes the discussions of the SRF working group on this technology during the ERL2005 workshop

  9. Superconducting devices at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Dahl, P.F.

    1978-04-01

    The various ongoing programs in applied superconductivity supported by BNL are summarized, including the development of high field ac and dc superconducting magnets for accelerators and other applications, of microwave deflecting cavities for high energy particle beam separators, and of cables for underground power transmission, and materials research on methods of fabricating new superconductors and on metallurgical properties affecting the performance of superconducting devices

  10. Superconducting magnets in the world of energy, especially in fusion power

    International Nuclear Information System (INIS)

    Komarek, P.

    1976-01-01

    Industrial applications of superconducting magnets are only feasible in the near future for superconducting monopolar machines and possible MHD generators. For superconducting synchronous machines, after the successful operation of machines in the MVA range, a new phase of basic investigations has started. Fundamental problems which could not be studied in the MVA machines, but which influence the design of large turbo-alternators, must now be investigated. Fusion power by magnetic confinement will probably be the largest field of application for superconducting magnets in the long run. The present research programmes require large superconducting magnets by the mid-1980s for the experimental reactors envisaged at that time. In addition to dc windings, pulse-operated superconducting windings are required in some systems, such as Tokamak. The high sensitivity of the overall plant efficiency and the active power demand of the pulsed windings require great efficiency from energy storage and transfer systems. Superconducting energy storage systems would be suitable for this, if transfer between inductances could be provided with sufficient efficiency. Basic experiments gave encouraging results. In power plant systems and electric machines an extremely high level of reliability and availability has been achieved. Less reliability will not be accepted for systems with superconducting magnets. This requires great efforts during the development work. (author)

  11. Large A.C. machines theory and investigation methods of currents and losses in stator and rotor meshes including operation with nonlinear loads

    CERN Document Server

    Boguslawsky, Iliya; Hayakawa, Masashi

    2017-01-01

    In this monograph the authors solve the modern scientific problems connected with A.C. motors and generators, based first on the detailed consideration of their physical phenomena. The authors describe the theory and investigative methods they developed and applied in practice, which are considered to be of essential interest for specialists in the field of the electrical engineering industry in European countries, the USA, Argentina, and Brazil, as well as in such countries as India, China, and Iran. This book will be of interest to engineers specialized in the field of the manufacture, operation, and repair of A.C. machines (motors and generators) as well as electric drives; to professors, lecturers, and post-graduate students of technical universities, who are specializing in the field of electric machine engineering and electric drives; and to students who are engaged in the field of high current techniques, electric drives, and electric machine engineering.

  12. Measuring ac losses in superconducting cables using a resonant circuit:Resonant current experiment (RESCUE)

    DEFF Research Database (Denmark)

    Däumling, Manfred; Olsen, Søren Krüger; Rasmussen, Carsten

    1998-01-01

    be recorded using, for example, a digital oscilloscope. The amplitude decay of the periodic voltage or current accurately reflects the power loss in the system. It consists of two components-an ohmic purely exponential one (from leads, contacts, etc.), and a nonexponential component originating from......A simple way to obtain true ac losses with a resonant circuit containing a superconductor, using the decay of the circuit current, is described. For the measurement a capacitor is short circuited with a superconducting cable. Energy in the circuit is provided by either charging up the capacitors...... with a certain voltage, or letting a de flow in the superconductor. When the oscillations are started-either by opening a switch in case a de is flowing or by closing a switch to connect the charged capacitors with the superconductor-the current (via a Rogowski coil) or the voltage on the capacitor can...

  13. Superconductivity at the industrial scale

    International Nuclear Information System (INIS)

    Tixador, P.; Lebrun, Ph.

    2011-01-01

    The discovery of superconductivity is 100 years old but theoretical works are still necessary: the BCS theory does not apply to the new families of high temperature superconducting materials discovered after 1986. In 2001 it was discovered that MgB 2 is superconducting at 39 K, this critical temperature is not the highest but MgB 2 is easy to produce and cheap. Today's highest critical temperature under atmospheric pressure is that of the HgTlBaCaCuO compound: 138 K. The complexity and the cost of cryogenic systems restrain the applications of superconductivity. The author reviews the applications of superconducting in medical imaging, particle detectors, and in the safety systems of power networks. (A.C.)

  14. Distribution of AC loss in a HTS magnet for SMES with different operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y., E-mail: xuyinghust@163.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, R and D Center of Applied Superconductivity, Huazhong University of Science and Technology, Wuhan 430074 (China); Tang, Y.; Ren, L.; Jiao, F. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, R and D Center of Applied Superconductivity, Huazhong University of Science and Technology, Wuhan 430074 (China); Song, M.; Cao, K.; Wang, D. [Yunnan Electric Power Research Institute, Kunming City 650217 (China); Wang, L.; Dong, H. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, R and D Center of Applied Superconductivity, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2013-11-15

    Highlights: •We present a model to calculate the distribution of AC loss for a storage magnet. •Comparative analysis of AC loss with different operating conditions has done. •The nonuniform distribution factor “d” is proposed to estimate the inhomogeneity of a storage magnet. •The model predicts the loss distribution and crucial areas which are suffering from the high AC loss. This is significant for the conduction-cooled structure design. -- Abstract: The AC loss induced in superconducting tape may affect the performance of a superconducting device applied to power system, such as transformer, cable, motor and even Superconducting Magnetic Energy Storage (SMES). The operating condition of SMES is changeable due to the need of compensation to the active or reactive power according to the demand of a power grid. In this paper, it is investigated that the distribution of AC loss for a storage magnet on different operating conditions, which is based on finite element method (FEM) and measured properties of BSCCO/Ag tapes. This analytical method can be used to optimize the SMES magnet.

  15. Winding machines for the manufacturing of superconductive coils of the main European fusion research machines

    CERN Document Server

    Cazzaniga, R; D’Urzo, C

    2005-01-01

    The successfull construction of large magnets passes through the development and application of non-conventional manufacturing processes. A difficult and delicate step in the manufacturing of superconducting coils is the conductor winding technique. It is often a challenging and technologically advanced process, developed according to the requirements of each project. An important aspect during the winding is to avoid any deformation of the cable cross section leading to a damage of the strands and to maintain the design features of the cable. A second aspect is to assure the suitable repeatability and a production rate for an industrial process. The winding line is a system of different machines linked and tuned together properly designed for each project. An adapted software assures the overall process control. TPA realized for ANSALDO Superconduttori the winding lines for many projects: TFMC (NET-TEAM), CMS (INFN-CERN), WENDELSTEIN W7-X (Max Planck Institute, IPP), etc. The experience acquired in this fiel...

  16. Superconducting magnet development in Japan

    International Nuclear Information System (INIS)

    Yasukochi, K.

    1983-01-01

    The present state of R and D works on the superconducting magnet and its applications in Japan are presented. On electrical rotating machines, 30 MVA superconducting synchronous rotary condenser (Mitsubishi and Fuji) and 50 MVA generator are under construction. Two ways of ship propulsion by superconducting magnets are developing. A superconducting magnetically levitated and linear motor propelled train ''MAGLEV'' was developed by the Japan National Railways (JNR). The superconducting magnet development for fusion is the most active field in Japan. The Cluster Test program has been demonstrated on a 10 T Nb 3 Sn coil and the first coil of Large Coil Task in IEA collaboration has been constructed and the domestic test was completed in JAERI. These works are for the development of toroidal coils of the next generation tokamak machine. R and D works on superconducting ohmic heating coil are in progress in JAERI and ETL. The latter group has constructed 3.8 MJ pulsed coil. A high ramp rate of changing field in pulsed magnet, 200 T/s, has been tested successfully. High Energy Physics Laboratory (KEK) are conducting active works. The superconducting μ meson channel and π meson channel have been constructed and are operating successfully. KEK has also a project of big accelerator named ''TRISTAN'', which is similar to ISABELLE project of BNL. Superconducting synchrotron magnets are developed for this project. The development of superconducting three thin wall solenoid has been started. One of them, CDF, is progressing under USA-Japan collaboration

  17. Dynamics of the resistive state of a narrow superconducting channel in the ac voltage-driven regime

    International Nuclear Information System (INIS)

    Yerin, Yu.S.; Fenchenko, V.N.

    2013-01-01

    Within the time-dependent Ginzburg-Landau equations the dynamics of the order parameter in superconducting narrow channels of different lengths is investigated in the ac voltage-driven regime. The resistive state of the system at low frequencies of the applied voltage is characterized by the formation of periodic-in-time groups of oscillating phase-slip centers (PSC). An increase in frequency reduces the duration of the existence of these periodic groups. Depending on the length of the channel the ac voltage either tends to revert the channel to the state with one central PSC in periodic groups or minimizes the number of forming PSCs and orders their pattern in the system. A further increase in frequency for rather short channels leads to suppression of the order parameter without any creation of PSCs. For systems, whose length exceeds the specified limit, the formation of PSC occurs after a certain time which increases rapidly with frequency. The current-voltage characteristics of rather short channels at different applied voltage frequencies are calculated too. It is found that the current-voltage characteristics have a step-like structure, and the height of the first step is determined by the quadruple value of the Josephson frequency.

  18. Development of superconducting ship propulsion system

    International Nuclear Information System (INIS)

    Sakuraba, Junji; Mori, Hiroyuki; Hata, Fumiaki; Sotooka, Koukichi

    1991-01-01

    When we plan displacement-type monohull high speed vessels, it is difficult to get the hull form with the wave-making resistance minimum, because the stern shape is restricted by arrangement of propulsive machines and shafts. A small-sized and light-weight propulsive machines will reduce the limit to full form design. Superconducting technology will have capability of realizing the small-sized and light-weight propulsion motor. The superconducting electric propulsion system which is composed of superconducting propulsion motors and generators, seems to be an ideal propulsion system for future vehicles. We have constructed a 480 kW superconducting DC homopolar laboratory test motor for developing this propulsion system. The characteristic of this motor is that it has a superconducting field winding and a segmented armature drum. The superconducting field winding which operates in the persistent current mode, is cooled by a condensation heat exchanger and helium refigerating system built into the cryostat of the superconducting field winding. The operating parameters of this motor agreed well with the design parameters. Using the design concepts of this motor, we have conceptually designed a 150,000-200,000 PS superconducting electric propulsive system for a displacement-type monohull high speed ship. (author)

  19. Superconducting pulsed magnets

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    Lecture 1. Introduction to Superconducting Materials Type 1,2 and high temperature superconductors; their critical temperature, field & current density. Persistent screening currents and the critical state model. Lecture 2. Magnetization and AC Loss How screening currents cause irreversible magnetization and hysteresis loops. Field errors caused by screening currents. Flux jumping. The general formulation of ac loss in terms of magnetization. AC losses caused by screening currents. Lecture 3. Twisted Wires and Cables Filamentary composite wires and the losses caused by coupling currents between filaments, the need for twisting. Why we need cables and how the coupling currents in cables contribute more ac loss. Field errors caused by coupling currents. Lecture 4. AC Losses in Magnets, Cooling and Measurement Summary of all loss mechanisms and calculation of total losses in the magnet. The need for cooling to minimize temperature rise in a magnet. Measuring ac losses in wires and in magnets. Lecture 5. Stab...

  20. Electrical protection of superconducting magnet systems

    International Nuclear Information System (INIS)

    Sutter, D.F.; Flora, R.H.

    1975-01-01

    The problem of dissipating the energy stored in the field of a superconducting magnet when a quench occurs has received considerable study. However, when the magnet becomes a system 4 miles in length whose normal operation is an ac mode, some re-examination of standard techniques for dissipating energy outside the magnets is in order. Data accumulated in the Fermilab Energy Doubler magnet development program shows that heating associated with the temporal and spatial development of quenches is highly localized and can result in temperatures damaging to the superconducting wire. The design and operation are discussed for several energy dumping schemes, compatible with the operation of ac superconducting magnets, wherein more than 70 percent of the stored energy can be dissipated outside the magnet. Instrumentation to detect quenches early in their development and circuits for dumping the field energy are described, and representative operating performance data for the dump circuits and data showing temporal development of quenches are presented. (auth)

  1. Playing catch with energy between two superconducting coils

    International Nuclear Information System (INIS)

    Masuda, Masayoshi; Shintomi, Takakazu; Asaji, Kiyoyuki.

    1979-03-01

    The first performance of playing catch with energy between two 100 kJ superconducting magnets has been presented. The mechanism of the energy transfer as an interface between the superconducting coils is a thyristorized DC-AC-DC converter. The obtained experimental efficiency of energy transfer has been compared with the theory and good agreement has been obtained. The method will offer a versatile extension of superconductive technique in energy problems. (author)

  2. Lightweight MgB2 superconducting 10 MW wind generator

    Science.gov (United States)

    Marino, I.; Pujana, A.; Sarmiento, G.; Sanz, S.; Merino, J. M.; Tropeano, M.; Sun, J.; Canosa, T.

    2016-02-01

    The offshore wind market demands a higher power rate and more reliable turbines in order to optimize capital and operational costs. The state-of-the-art shows that both geared and direct-drive conventional generators are difficult to scale up to 10 MW and beyond due to their huge size and weight. Superconducting direct-drive wind generators are considered a promising solution to achieve lighter weight machines. This work presents an innovative 10 MW 8.1 rpm direct-drive partial superconducting generator using MgB2 wire for the field coils. It has a warm iron rotor configuration with the superconducting coils working at 20 K while the rotor core and the armature are at ambient temperature. A cooling system based on cryocoolers installed in the rotor extracts the heat from the superconducting coils by conduction. The generator's main parameters are compared against a permanent magnet reference machine, showing a significant weight and size reduction. The 10 MW superconducting generator concept will be experimentally validated with a small-scale magnetic machine, which has innovative components such as superconducting coils, modular cryostats and cooling systems, and will have similar size and characteristics as the 10 MW generator.

  3. Alternating current loss characteristics in (bismuth,lead)SCCO and yttrium barium copper oxide superconducting tapes

    Science.gov (United States)

    Nguyen, Doan Ngoc

    Alternating current (AC) loss and current carrying capacity are two of the most crucial considerations in large-scale power applications of high temperature superconducting (HTS) conductors. AC losses result in an increased thermal load for cooling machines, and thus increased operating costs. Furthermore, AC losses can stimulate quenching phenomena or at least decrease the stability margin for superconducting devices. Thus, understanding AC losses is essential for the development of HTS AC applications. The main focus of this dissertation is to make reliable total AC loss measurements and interpret the experimental results in a theoretical framework. With a specially designed magnet, advanced total AC loss measurement system in liquid nitrogen (77 K) has been successfully built. Both calorimetric and electromagnetic methods were employed to confirm the validity of the measured results and to have a more thorough understanding of AC loss in HTS conductors. The measurement is capable of measuring total AC loss in HTS tapes over a wide range of frequency and amplitude of transport current and magnetic field. An accurate phase control technique allows measurement of total AC loss with any phase difference between the transport current and magnetic field by calorimetric method. In addition, a novel total AC loss measurement system with variable temperatures from 30 K to 100 K was successfully built and tested. Understanding the dependence of AC losses on temperature will enable optimization of the operating temperature and design of HTS devices. As a part of the dissertation, numerical calculations using Brandt's model were developed to study electrodynamics and total AC loss in HTS conductors. In the calculations, the superconducting electrical behavior is assumed to follow a power-law model. In general, the practical properties of conductors, including field-dependence of critical current density Jc, n-value and non-uniform distribution of Jc, can be accounted for in

  4. Superconducting Wind Turbine Generators

    Directory of Open Access Journals (Sweden)

    Yunying Pan

    2016-08-01

    Full Text Available Wind energy is well known as a renewable energy because its clean and less polluted characteristic, which is the foundation of development modern wind electricity. To find more efficient wind turbine is the focus of scientists around the world. Compared from conventional wind turbines, superconducting wind turbine generators have advantages at zero resistance, smaller size and lighter weight. Superconducting wind turbine will inevitably become the main trends in this area. This paper intends to introduce the basic concept and principle of superconductivity, and compare form traditional wind turbine to obtain superiority, then to summary three proposed machine concept.While superconductivity have difficulty  in modern technology and we also have proposed some challenges in achieving superconducting wind turbine finally.

  5. Design Study of Fully Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Jensen, Bogi Bech

    2015-01-01

    In this paper, two fully superconducting generators employing MgB2 armature winding, with YBCO and MgB2 field winding respectively, are presented and analyzed. The ac loss in armature winding is estimated, and a simple comparative study is carried out. The results show that both electromagnetic...... designs for fully superconducting generators are promising with respect to the power density. However, the cost of removing ac loss in armature winding is as high as $900 000. It is also noted that with the current price of YBCO tape, the generator employing MgB 2 field winding would have lower cost....

  6. Development of superconducting magnetic bearing using superconducting coil and bulk superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Seino, H; Nagashima, K; Arai, Y [Railway Technical Research Institute, Hikari-cho 2-8-38, Kokubunji-shi, Tokyo (Japan)], E-mail: seino@rtri.or.jp

    2008-02-01

    The authors conducted a study on superconducting magnetic bearing, which consists of superconducting rotor and stator to apply the flywheel energy-storage system for railways. In this study, high temperature bulk superconductor (HTS bulk) was combined with superconducting coils to increase the load capacity of the bearing. In the first step of the study, the thrust rolling bearing was selected for application by using liquid nitrogen cooled HTS bulk. 60mm-diameter HTS bulks and superconducting coil which generated a high gradient of magnetic field by cusp field were adopted as a rotor and a stator for superconducting magnetic bearing, respectively. The results of the static load test and the rotation test, creep of the electromagnetic forces caused by static flux penetration and AC loss due to eccentric rotation were decreased to the level without any problems in substantial use by using two HTS bulks. In the result of verification of static load capacity, levitation force (thrust load) of 8900N or more was supportable, and stable static load capacity was obtainable when weight of 460kg was levitated.

  7. Development of superconducting magnetic bearing using superconducting coil and bulk superconductor

    International Nuclear Information System (INIS)

    Seino, H; Nagashima, K; Arai, Y

    2008-01-01

    The authors conducted a study on superconducting magnetic bearing, which consists of superconducting rotor and stator to apply the flywheel energy-storage system for railways. In this study, high temperature bulk superconductor (HTS bulk) was combined with superconducting coils to increase the load capacity of the bearing. In the first step of the study, the thrust rolling bearing was selected for application by using liquid nitrogen cooled HTS bulk. 60mm-diameter HTS bulks and superconducting coil which generated a high gradient of magnetic field by cusp field were adopted as a rotor and a stator for superconducting magnetic bearing, respectively. The results of the static load test and the rotation test, creep of the electromagnetic forces caused by static flux penetration and AC loss due to eccentric rotation were decreased to the level without any problems in substantial use by using two HTS bulks. In the result of verification of static load capacity, levitation force (thrust load) of 8900N or more was supportable, and stable static load capacity was obtainable when weight of 460kg was levitated

  8. Non-conventional electrical machines

    CERN Document Server

    Rezzoug, Abderrezak

    2013-01-01

    The developments of electrical machines are due to the convergence of material progress, improved calculation tools, and new feeding sources. Among the many recent machines, the authors have chosen, in this first book, to relate the progress in slow speed machines, high speed machines, and superconducting machines. The first part of the book is dedicated to materials and an overview of magnetism, mechanic, and heat transfer.

  9. A superconducting magnetic gear

    International Nuclear Information System (INIS)

    Campbell, A M

    2016-01-01

    A comparison is made between a magnetic gear using permanent magnets and superconductors. The objective is to see if there are any fundamental reasons why superconducting magnets should not provide higher power densities than permanent magnets. The gear is based on the variable permeability design of Attilah and Howe (2001 IEEE Trans. Magn. 37 2844–46) in which a ring of permanent magnets surrounding a ring of permeable pole pieces with a different spacing gives an internal field component at the beat frequency. Superconductors can provide much larger fields and forces but will saturate the pole pieces. However the gear mechanism still operates, but in a different way. The magnetisation of the pole pieces is now constant but rotates with angle at the beat frequency. The result is a cylindrical Halbach array which produces an internal field with the same symmetry as in the linear regime, but has an analytic solution. In this paper a typical gear system is analysed with finite elements using FlexPDE. It is shown that the gear can work well into the saturation regime and that the Halbach array gives a good approximation to the results. Replacing the permanent magnets with superconducting tapes can give large increases in torque density, and for something like a wind turbine a combined gear and generator is possible. However there are major practical problems. Perhaps the most fundamental is the large high frequency field which is inevitably present and which will cause AC losses. Also large magnetic fields are required, with all the practical problems of high field superconducting magnets in rotating machines. Nevertheless there are ways of mitigating these difficulties and it seems worthwhile to explore the possibilities of this technology further. (paper)

  10. FY 2000 research and development of fundamental technologies for AC superconducting power devices. R and D of fundamental technologies for superconducting power cables and faults current limiters, R and D of superconducting magnets for power applications, and study on the total systems and related subjects; 2000 nendo koryu chodendo denryoku kiki kiban gijutsu kenkyu kaihatsu seika hokokusho. Chodendo soden cable kiban gijutsu no kenkyu kaihatsu, chodendo genryuki kiban gijutsu no kenkyu kaihatsu, denryokuyo chodendo magnet no kenkyu kaihatsu, total system nado no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    The project for research and development of fundamental technologies for AC superconducting power devices has been started, and the FY 2000 results are reported. The R and D of fundamental technologies for superconducting power cables include grasping the mechanical characteristics associated with integration necessary for fabrication of large current capacity and long cables; development of barrier cable materials by various methods; and development of short insulated tubes as cooling technology for long superconducting cables, and grasping its thermal/mechanical characteristics. The R and D of faults current limiters include introduction of the unit for superconducting film fabrication, determination of the structures and layouts for large currents, and improvement of performance of each device for high voltages. R and D of superconducting magnets for power applications include grasping the fundamental characteristics of insulation at cryogenic temperature, completion of the insulation designs for high voltage/current lead bushing, and development of prototype sub-cooled nitrogen cooling unit for cooling each AC power device. Study on the total systems and related subjects include analysis for stabilization of the group model systems, to confirm improved voltage stability when the superconducting cable is in service. (NEDO)

  11. Superconductivity in technology

    International Nuclear Information System (INIS)

    Komarek, P.

    1976-01-01

    Physics, especially high energy physics and solid state physics was the first area in which superconducting magnets were used but in the long run, the most extensive application of superconductivity will probably be in energy technology. Superconducting power transmission cables, magnets for energy conversion in superconducting electrical machines, MHD-generators and fusion reactors and magnets for energy storage are being investigated. Magnets for fusion reactors will have particularly large physical dimensions, which means that much development effort is still needed, for there is no economic alternative. Superconducting surfaces in radio frequency cavities can give Q-values up to a factor of 10 6 higher than those of conventional resonators. Particle accelerators are the important application. And for telecommunication, simple coaxial superconducting radio frequency cables seem promising. The tunnel effect in superconducting junctions is now being developed commercially for sensitive magnetometers and may soon possibly feature in the memory cells of computer devices. Hence superconductivity can play an important role in the technological world, solving physical and technological problems and showing economic advantages as compared with possible conventional techniques, bearing also in mind the importance of reliability and safety. (author)

  12. Superconductivity in heavily boron-doped silicon carbide

    Directory of Open Access Journals (Sweden)

    Markus Kriener, Takahiro Muranaka, Junya Kato, Zhi-An Ren, Jun Akimitsu and Yoshiteru Maeno

    2008-01-01

    Full Text Available The discoveries of superconductivity in heavily boron-doped diamond in 2004 and silicon in 2006 have renewed the interest in the superconducting state of semiconductors. Charge-carrier doping of wide-gap semiconductors leads to a metallic phase from which upon further doping superconductivity can emerge. Recently, we discovered superconductivity in a closely related system: heavily boron-doped silicon carbide. The sample used for that study consisted of cubic and hexagonal SiC phase fractions and hence this led to the question which of them participated in the superconductivity. Here we studied a hexagonal SiC sample, free from cubic SiC phase by means of x-ray diffraction, resistivity, and ac susceptibility.

  13. Experience with the Quality Assurance of the Superconducting Electrical Circuits of the LHC Machine

    CERN Document Server

    Bozzini, D; Kotarba, A; Mess, Karl Hubert; Olek, S; Russenschuck, Stephan

    2006-01-01

    The coherence between the powering reference database for the LHC and the Electrical Quality Assurance (ELQA) is guaranteed on the procedural level. However, a challenge remains the coherence between the database, the magnet test and assembly procedures, and the connection of all superconducting circuits in the LHC machine. In this paper, the methods, tooling, and procedures for the ELQA during the assembly phase of the LHC will be presented in view of the practical experience gained in the LHC tunnel. Some examples of detected polarity errors and electrical non-conformities will be presented. The parameters measured at ambient temperature, such as the dielectric insulation of circuits, will be discussed.

  14. Superconductive energy storage magnet study

    International Nuclear Information System (INIS)

    Rhee, S.W.

    1982-01-01

    Among many methods of energy storages the superconducting energy storage has been considered as the most promising method. Many related technical problems are still unsolved. One of the problems is the magnetizing and demagnetizing loss of superconducting coil. This loss is mainly because of hysteresis of pinning force. In this paper the hysteresis loss is calculated and field dependence of the a.c. losses is explained. The ratio of loss and stored energy is also calculated. (Author)

  15. Loss and Inductance Investigation in Superconducting Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Tønnesen, Ole; Træholt, Chresten

    1999-01-01

    An important parameter in the design and optimization of a superconducting cable conductor is the control of the current distribution among single tapes and layers. This distribution is to a large degree determined by inductances, since the resistances are low. The self and mutual inductances...... of transport current and current distribution.This presentation is based on a number of experiments performed on prototype superconducting cable conductors. The critical current (1uV/cm) of the conductor at 77K was 1590 A (cable #1) and 3240 A (cable #2) respectively.At an rms current of 2 kA (50 Hz) the AC......-loss was measured on cable #2 to 0.6W/mxphase. This is, to our knowledge, the lowest AC-loss (at 2kA and 77K) of a high temperature superconducting cable conductor reported so far....

  16. AC-loss considerations of a pulse SMES for an accelerator

    International Nuclear Information System (INIS)

    Lyly, M; Hiltunen, I; Jaervelae, J; Korpela, A; Lehti, L; Stenvall, A; Mikkonen, R

    2010-01-01

    In particle accelerators quasi-DC superconducting magnets are used to keep particles in desired tracks. The needed rapid field variations of these high energy magnets require large energy bursts. If these bursts are taken from and fed back to the utility grid, its voltage is distorted and the quality of the electricity degrades. In addition, these bursts may decrease operation life time of generators and extra arrangements may be required by the electricity producers. Thus, an energy storage is an essential component for a cost-effective particle accelerator. Flywheels, capacitors and superconducting magnetic energy storage (SMES) are possible options for these relatively large and high power energy storages. Here we concentrate on AC-loss of a pulse SMES aiming to demonstrate the feasibility of NbTi SMES in a particle accelerator. The designing of a SMES requires highly reliable AC-loss simulations. In this paper, calorimetric AC-loss measurements of a NbTi magnet have been carried out to consider conductor's suitability in a pulse SMES. In addition, the measured results are compared with AC-loss simulations.

  17. Predicting AC loss in practical superconductors

    International Nuclear Information System (INIS)

    Goemoery, F; Souc, J; Vojenciak, M; Seiler, E; Klincok, B; Ceballos, J M; Pardo, E; Sanchez, A; Navau, C; Farinon, S; Fabbricatore, P

    2006-01-01

    Recent progress in the development of methods used to predict AC loss in superconducting conductors is summarized. It is underlined that the loss is just one of the electromagnetic characteristics controlled by the time evolution of magnetic field and current distribution inside the conductor. Powerful methods for the simulation of magnetic flux penetration, like Brandt's method and the method of minimal magnetic energy variation, allow us to model the interaction of the conductor with an external magnetic field or a transport current, or with both of them. The case of a coincident action of AC field and AC transport current is of prime importance for practical applications. Numerical simulation methods allow us to expand the prediction range from simplified shapes like a (infinitely high) slab or (infinitely thin) strip to more realistic forms like strips with finite rectangular or elliptic cross-section. Another substantial feature of these methods is that the real composite structure containing an array of superconducting filaments can be taken into account. Also, the case of a ferromagnetic matrix can be considered, with the simulations showing a dramatic impact on the local field. In all these circumstances, it is possible to indicate how the AC loss can be reduced by a proper architecture of the composite. On the other hand, the multifilamentary arrangement brings about a presence of coupling currents and coupling loss. Simulation of this phenomenon requires 3D formulation with corresponding growth of the problem complexity and computation time

  18. RADIOFREQUENCY SUPERCONDUCTIVITY: Workshop

    International Nuclear Information System (INIS)

    Lengeler, Herbert

    1989-01-01

    Superconducting radiofrequency is already playing an important role in the beam acceleration system for the TRISTAN electron-positron collider at the Japanese KEK Laboratory and new such systems are being prepared for other major machines. Thus the fourth Workshop on Radiofrequency Superconductivity, organized by KEK under the chairmanship of local specialist Yuzo Kojima and held just before the International Conference on High Energy Accelerators, had much progress to review and even more to look forward to

  19. Report on results for fiscal 1997 on development of superconducting electric power application technology. Pt. 1. R and D of superconducting wire, R and D of superconducting generator, studies on total system, R and D of refrigeration system, and verification test; 1997 nendo chodendo denryoku oyo gijutsu kaihatsu seika hokokusho. 1. Chodendo senzai no kenkyu kaihatsu, chodendo hatsudenki no kenkyu kaihatsu, total system no kenkyu, reito system no kenkyu kaihatsu, jissho shiken

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    This report explains the outline as Part 1. In fiscal 1997, the 10th year of the project, a multi cylindrical rotary model for which an in-situ verification test was finished was brought back to the plant and dismantled for examination, while the in-situ verification test of a slow-response type model machine rotor was conducted in combination with a refrigeration system. In addition, in the research of AC wire materials and oxide based materials, studies were made with a purpose of high characterization and long wire materialization. In the metallic materials, a 10kANbTi conductor was developed while, in oxide-based materials, research was done on performance improvement and wire materialization based on various synthesizing methods. The manufacturing, factory test and in-situ text were conducted for a 70,000kW model machine with the purpose of R and D of a 200,000kW class pilot machine. Examination was made on the test method of the 70,000kW class model machine, operation technology of a superconducting generation system, and the effect of introducing the superconducting generator into a power system. In the conventional refrigeration system, a single unit test was carried out for the liquefaction, liquid storing capacity, etc., of the system. The 70,000kW class model machine was put through a test for confirming the general operation including the refrigeration system. (NEDO)

  20. Lightweight MgB2 superconducting 10 MW wind generator

    International Nuclear Information System (INIS)

    Marino, I; Pujana, A; Sarmiento, G; Sanz, S; Merino, J M; Tropeano, M; Sun, J; Canosa, T

    2016-01-01

    The offshore wind market demands a higher power rate and more reliable turbines in order to optimize capital and operational costs. The state-of-the-art shows that both geared and direct-drive conventional generators are difficult to scale up to 10 MW and beyond due to their huge size and weight. Superconducting direct-drive wind generators are considered a promising solution to achieve lighter weight machines. This work presents an innovative 10 MW 8.1 rpm direct-drive partial superconducting generator using MgB 2 wire for the field coils. It has a warm iron rotor configuration with the superconducting coils working at 20 K while the rotor core and the armature are at ambient temperature. A cooling system based on cryocoolers installed in the rotor extracts the heat from the superconducting coils by conduction. The generator’s main parameters are compared against a permanent magnet reference machine, showing a significant weight and size reduction. The 10 MW superconducting generator concept will be experimentally validated with a small-scale magnetic machine, which has innovative components such as superconducting coils, modular cryostats and cooling systems, and will have similar size and characteristics as the 10 MW generator. (paper)

  1. Modeling and comparison of superconducting linear actuators for highly dynamic motion

    Directory of Open Access Journals (Sweden)

    Bruyn B.J.H. de

    2015-12-01

    Full Text Available This paper presents a numerical modeling method for AC losses in highly dynamic linear actuators with high temperature superconducting (HTS tapes. The AC losses and generated force of two actuators, with different placement of the cryostats, are compared. In these actuators, the main loss component in the superconducting tapes are hysteresis losses, which result from both the non-sinusoidal phase currents and movement of the permanent magnets. The modeling method, based on the H-formulation of the magnetic fields, takes into account permanent magnetization and movement of permanent magnets. Calculated losses as function of the peak phase current of both superconducting actuators are compared to those of an equivalent non-cryogenic actuator.

  2. Critical current density measurement of thin films by AC susceptibility based on the penetration parameter h

    DEFF Research Database (Denmark)

    Li, Xiao-Fen; Grivel, Jean-Claude; Abrahamsen, Asger B.

    2012-01-01

    We have numerically proved that the dependence of AC susceptibility χ of a E(J) power law superconducting thin disc on many parameters can be reduced to one penetration parameter h, with E the electric field and J the current density. Based on this result, we propose a way of measuring the critical...... current density Jc of superconducting thin films by AC susceptibility. Compared with the normally used method based on the peak of the imaginary part, our method uses a much larger range of the AC susceptibility curve, thus allowing determination of the temperature (T) dependence of Jc from a normally...

  3. Magnetic anomaly in superconducting TmRh4B4

    International Nuclear Information System (INIS)

    Smith, J.L.; Huang, C.Y.; Tsou, J.J.; Ho, J.C.

    1978-01-01

    The magnetic and superconducting properties of TmRh 4 B 4 (which becomes superconducting at 9.6 K) by means of ac and dc magnetic susceptibility and specific heat measurements are investigated. At 10.7 K, an ac susceptibility peak similar to those found in spin glasses has been observed. In addition, a pronounced specific heat peak has been observed at 11.4 K. The susceptibility peak is essentially unaffected by substitution of 1% Lu or Er for the Tm, but it diminishes when much larger amounts of Er are substituted. The physical origin of this anomalous peak will be discussed

  4. Superconducting magnets for a muon collider

    International Nuclear Information System (INIS)

    Green, M.A.

    1996-01-01

    The existence of a muon collider will be dependent on the use of superconducting magnets. Superconducting magnets for the μ - μ + collider will be found in the following locations: the π - π + capture system, the muon phase rotation system, the muon cooling system, the recirculating acceleration system, the collider ring, and the collider detector system. This report describes superconducting magnets for each of these sections except the detector. In addition to superconducting magnets, superconducting RF cavities will be found in the recirculating accelerator sections and the collider ring. The use of superconducting magnets is dictated by the need for high magnetic fields in order to reduce the length of various machine components. The performance of all of the superconducting magnets will be affected the energy deposited from muon decay products. (orig.)

  5. NORPAS - NORdic program of applied superconductivity. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mikkonen, R. [ed.

    1995-12-31

    High temperature superconducting (HTS) wire is rapidly maturing into a working material being produced in ever larger quantities and being used in more significant demonstrations and prototypes. Conductor is now produced routinely in several hundred meter lengths with reproducible results. Current density has progressed to a level suitable for demonstration on many applications. As with any technology trying to find a niche, widespread commercialization can only occur if the new technology can match the performance of an existing technology at a lower cost, or the new technology represents a breakthrough in capabilities, irrespective of cost, in turn enabling functionality previously thought impossible. There are two obvious areas where HTS will have significant benefit. The first is all applications which will notably benefit from a reduction in refrigeration power. The second area is the market of very high field magnets where there is no viable alternative. Applications under consideration for HTS include: (1) Rotating electrical machines (synchronous ac and homopolar dc motors), (2) Underground transmission cables, (3) Superconducting Magnetic Energy Storage (SMES), (4) Utility distribution equipment such as transformers and current limiters, (5) Commercial processing applications such as magnetic separation. (6) Military applications such as mine clearing, (7) Specialty magnets such as high field inserts

  6. Numerical solution of critical state in superconductivity by finite element software

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Z; Campbell, A M; Coombs, T A [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2006-12-15

    A numerical method is proposed to analyse the electromagnetic behaviour of systems including high-temperature superconductors (HTSCs) in time-varying external fields and superconducting cables carrying AC transport current. The E-J constitutive law together with an H-formulation is used to calculate the current distribution and electromagnetic fields in HTSCs, and the magnetization of HTSCs; then the forces in the interaction between the electromagnet and the superconductor and the AC loss of the superconducting cable can be obtained. This numerical method is based on solving the partial differential equations time dependently and is adapted to the commercial finite element software Comsol Multiphysics 3.2. The advantage of this method is to make the modelling of the superconductivity simple, flexible and extendable.

  7. A step towards controlled fusion reactors: Tore Supra tokamak with superconducting magnets

    International Nuclear Information System (INIS)

    Turck, B.

    1988-01-01

    Tore Supra technology has to solve all the problems related to the development and the installaion of superconducting coils and associated cryogenic devices. Tore Supra will allow to get a significative experience to prepare next machines. Specifications and needs of tokamaks concerning the superconducting coils of future machines are recalled [fr

  8. Exotic Magnetic Orders and Their Interplay with Superconductivity

    DEFF Research Database (Denmark)

    Christensen, Morten Holm

    Superconductivity represents one of the most important scientific discoveries of the 20th century. The practical applications are numerous ranging from clean energy storage and MRI machines to quantum computers. However, the low temperatures required for superconductivity prohibits many practical...... applications. The more recent discovery of high-temperature superconductors, with superconducting transition temperatures above 100~K, has led to the hope that superconductivity at room-temperature might be achievable, although a complete theoretical understanding of the high-temperature superconductors...

  9. Measurements of the surface impedance and the ac critical field of superconducting thin tin films at 10 GHz

    International Nuclear Information System (INIS)

    Spencer, G.L.

    1976-01-01

    The surface impedances and ac critical fields of superconducting thin tin films were studied. These experiments were performed using a superconducting frequency stabilized microwave cavity of high Q. Measurements of the power losses in the cavity and the center frequency of the cavity were used to determine the surface impedance and the critical field of a thin film sample placed in the cavity. In this case a theoretical treatment based on a model proposed by I.O. Kulik was used to fit the data. The general agreement between the modified Kulik treatment and the data, obtained in this experiment, was substantial. The second method was to modify the thin film data to correspond to a bulk situation. This modification was accomplished by taking into account the measuring techniques used and the geometric consideration inherent in the experiment. The comparison between the modified experimental data and calculations obtained from the Mattis-Bardeen bulk model was generally very good. One aspect of the results which was not explained was the presence of a slight increase in the surface resistance in the vicinity of the transition temperature. The critical field measurements were compared to the (1 - (T/T/sub c/)/sup 1/2) dependence predicted by Bardeen. If it is assumed that substantial microwave heating took place in the sample near T/sub c/, then remarkable agreement with the Bardeen model can be reached

  10. Rotating electrical machines part 2 : methods for determining losses and efficiency of rotating electrical machinery form tests (excl. machines for traction vehicles)

    CERN Document Server

    International Electrotechnical Commission. Geneva

    1972-01-01

    Applies to d.c. machines and to a.c. synchronous and induction machines. The principles can be applied to other types of machines such as rotary converters, a.c. commutator motors and single-phase induction motors for which other methods of determining losses are used.

  11. Comparison study of cable geometries and superconducting tape layouts for high-temperature superconductor cables

    Science.gov (United States)

    Ta, Wurui; Shao, Tianchong; Gao, Yuanwen

    2018-04-01

    High-temperature superconductor (HTS) rare-earth-barium-copper-oxide (REBCO) tapes are very promising for use in high-current cables. The cable geometry and the layout of the superconducting tapes are directly related to the performance of the HTS cable. In this paper, we use numerical methods to perform a comparison study of multiple-stage twisted stacked-tape cable (TSTC) conductors to find better cable structures that can both improve the critical current and minimize the alternating current (AC) losses of the cable. The sub-cable geometry is designed to have a stair-step shape. Three superconducting tape layouts are chosen and their transport performance and AC losses are evaluated. The magnetic field and current density profiles of the cables are obtained. The results show that arrangement of the superconducting tapes from the interior towards the exterior of the cable based on their critical current values in descending order can enhance the cable's transport capacity while significantly reducing the AC losses. These results imply that cable transport capacity improvements can be achieved by arranging the superconducting tapes in a manner consistent with the electromagnetic field distribution. Through comparison of the critical currents and AC losses of four types of HTS cables, we determine the best structural choice among these cables.

  12. Superconducting A.C. generators. Some recent experimental investigations

    International Nuclear Information System (INIS)

    Ross, J.S.H.; Smith, D.A.

    1978-01-01

    Experimental work is reported which has been carried out in the past three years aimed at evaluating the materials and the design features applicable to large superconducting generators. Two main topics are considered: (1) A detailed and comprehensive investigation into the physical properties of a six tonne forging in austenitic stainless steel AISI 316LN. (2) The design of a system to transfer helium onto and from a rotating shaft. (UK)

  13. Iron-YBCO heterostructures and their application for trapped field superconducting motor

    International Nuclear Information System (INIS)

    Granados, X; Bartolome, E; Obradors, X; Tornes, M; Rodrigues, L; Gawalek, W; McCulloch, M; Hughes, D Dew; Campbell, A; Coombs, T; Ausloos, M; Cloots, R

    2006-01-01

    In this work we report on the magnetic behavior of the heterostructures formed by bulk based YBCO rings and ferromagnetic yoke. The magnetization cycle has been performed by an In-Field Hall Mapping technique. A video-like recording of the magnetization process makes it possible to obtain the magnetization of selected areas. The current flowing through the superconducting rings can be deduced from the magnetic field maps. The displacement of the peak of magnetization due to the flux reversal produced by the magnetization of the yoke is also considered. These hybrid heterostructures formed by ferromagnetic and superconducting material have been applied in the construction of the rotor for a brushless AC motor. The design and construction of this machine was carried out within the framework of the TMR Network SUPERMACHINES. The rotor has been designed in a quadrupolar configuration by cutting large YBCO 'window frames' from seeded melt-textured single domain YBCO pellets. This rotor has been coupled to a conventional stator of copper coils wound on an iron armature. The stator can be excited both in bipolar or quadrupolar mode. We report on the behaviour of the motor after a field cooling process when excited in quadrupolar mode

  14. Stability of superconducting cables for use in large magnet systems

    International Nuclear Information System (INIS)

    Tateishi, Hiroshi; Schmidt, C.

    1992-01-01

    The construction of large superconducting magnets requires the development of complicated conductor types, which can fulfill the specific requirements of different types of magnets. A rather hard boundary condition for large magnets is the presence of fast changing magnetic fields. In the Institute of Technical Physics of the Karlsruhe Nuclear Research Center, Germany, a superconducting cable was developed for use in poloidal field coils in Tokamak experiments. This 'POLO'-cable exhibits low losses in a magnetic ac-field and a high stability margin. In the present article the requirements on a superconducting cable are described, as well as the mechanisms of ac-losses and the calculation of the stability limit. Calculated values are compared with experimental data. Some unresolved problems concerning the stability of large magnets are discussed taking the example of the POLO-cable. (author)

  15. Alternating current losses of a 10 metre long low loss superconducting cable conductor determined from phase sensitive measurements

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten

    1999-01-01

    The ac loss of a superconducting cable conductor carrying an ac current is small. Therefore the ratio between the inductive (out-of-phase) and the resistive (in-phase) voltages over the conductor is correspondingly high. In vectorial representations this results in phase angles between the current......-in amplifiers can be exploited. In this paper we present the results from ac-loss measurements on a low loss 10 metre long high temperature superconducting cable conductor using such a correction scheme. Measurements were carried out with and without a compensation circuit that could reduce-the inductive...... voltage. The 1 mu V cm(-1) critical current of the conductor was 3240 A at 77 K. At an rms current of 2 kA (50 Hz) the ac loss was derived to be 0.6 +/- 0.15 W m(-1). This is, to the best of our knowledge, the lowest value of ac loss of a high temperature superconducting cable conductor reported so far...

  16. An illustration of how sciences may be combined at Cea: parallel progress in superconductivity, particle physics, medical imaging and fusion

    International Nuclear Information System (INIS)

    Duchateau, J.L.; Devred, A.; Kircher, F.; Meuris, Ch.; Schild, Th.; Rousset, B.

    2005-01-01

    Superconductivity was hailed as the most important achievement of modern physics when it was discovered in 1911. Since then the enthusiasm has damped a bit because superconductivity still requires very low temperatures. This article gives an historical account of the application of superconductivity to the research programs and achievement of Cea (French atomic energy board). The first uses were dedicated to the design of superconducting magnets. We can note the delivery in 1989 of 246 quadrupolar magnets for bending particle beams for the HERA accelerator. As for the LHC (large hadron collider) project, Cea-Grenoble has a key role in the development of the cryogenic system and Cea-Saclay is responsible of the design of 400 quadrupolar magnets, it will have to fabricate 3 prototypes and the mass production will be made in Germany. A second sector involving superconductivity is thermonuclear devices through magnetic confinement. Tore-Supra has been for 10 years the only big fusion machine involving a superconducting system. In ITER all the coils necessary to the plasma confinement will be superconducting, it will represent 700 tons of superconducting wires. The research programs linked to the ITER project have led to the design of a new superconducting material: the niobium-tin (Nb 3 Sn). A third sector is medical imaging in which Cea is involved since the eighties. Cea-Saclay will home the Neurospin center whose purpose is to assess the limit of brain imaging from mice to man. Cea has to design magnets in the range of 11 tesla with a one meter broad clearance, the selected technology is that of superconducting magnets cooled by pressurized superfluid helium. (A.C.)

  17. An establish attempt of reasons of machining splinter formation in AC44200 alloy high pressure die castings

    Directory of Open Access Journals (Sweden)

    J. Mutwil

    2008-10-01

    Full Text Available A problem of splinter formation during machining the AC44200 alloy high pressure die casting has been experimental investigated. Inorder to establish the reason of this occurrence a set of 200 high pressure die casting of the tensile strength samples have been prepared. The tensile tests were carried out using a Zwick Z050 universal testing machine. JM-SPC program has been used for statistical analysis of test results. A large variability of tensile strength results has been found. In order to find the reason of this variability the fracture surface investigations (macrographs for all of samples and SEM micrographs for chosen samples have been carried out. It has been establish that in all cases a significant decrease of tensile strength was caused by presence of inclusions or porosity. In lot of cases the inclusions have a form of oxide film.

  18. A Course on Applied Superconductivity Shared by Four Departments

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Abrahamsen, Asger Bech; Sørensen, Mads Peter

    2011-01-01

    superconductivity the focus was on an application, which could benefit from using superconductors. The application used in this course was superconducting generators for direct drive wind turbines. As part of the course the students built a small-scale superconducting machine and set up finite element models...... of that machine as well as large-scale wind turbine generators with superconductors and also permanent magnet generators. The course was assessed by a student conference contribution and reports from the students. The quality of the course was evaluated by interviewing the students after the course had finished....... The students were very pleased with the course and gave suggestions of how the course could be improved further....

  19. Superconducting magnets 1992

    International Nuclear Information System (INIS)

    1993-06-01

    This report discusses the following topics on Superconducting Magnets; SSC Magnet Industrialization; Collider Quadrupole Development; A Record-Setting Magnet; D20: The Push Beyond 10T; Nonaccelerator Applications; APC Materials Development; High-T c at Low Temperature; Cable and Cabling-Machine Development; and Analytical Magnet Design

  20. Large Superconducting Magnet Systems

    CERN Document Server

    Védrine, P.

    2014-07-17

    The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb−Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb$_{3}$Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

  1. Large Superconducting Magnet Systems

    Energy Technology Data Exchange (ETDEWEB)

    Védrine, P [Saclay (France)

    2014-07-01

    The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb−Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb3Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

  2. Developments of engineering applications of superconductivity at IRD

    International Nuclear Information System (INIS)

    Appleton, A.D.

    1982-01-01

    The current status of research and development in the fields of superconducting dc motors, ac generators and fault current limiters at International Research and Development Co Ltd is described. (U.K.)

  3. Winding machines for the manufacturing of superconductive coils of the main European fusion research machines

    International Nuclear Information System (INIS)

    Cazzaniga, Rodolfo; Valle, N.; D'Urzo, C.

    2005-01-01

    The successful construction of large magnets passes through the development and application of non-conventional manufacturing processes. A difficult and delicate step in the manufacturing of superconducting coils is the conductor winding technique. It is often a challenging and technologically advanced process, developed according to the requirements of each project. An important aspect during the winding is to avoid any deformation of the cable cross section leading to a damage of the strands and to maintain the design features of the cable. A second aspect is to assure the suitable repeatability and a production rate for an industrial process. The winding line is a system of different machines linked and tuned together properly designed for each project. An adapted software assures the overall process control. TPA realized for ANSALDO Superconduttori the winding lines for many projects: TFMC (NET-TEAM), CMS (INFN-CERN), WENDELSTEIN W7-X (Max Planck Institute, IPP), etc. The experience acquired in this field by ANSALDO Superconduttori and by TPA (as manufacturing tools and equipments supplier) has been acknowledged by CERN with 'The CMS Gold Award' of the Year 2004. The paper describes the main features of the winding lines, the main problems, the technical solutions used for the above mentioned projects and the new ideas for the forthcoming ones

  4. Superconducting magnets

    International Nuclear Information System (INIS)

    Willen, E.

    1996-01-01

    Superconducting dipole magnets for high energy colliders are discussed. As an example, the magnets recently built for the Relativistic Heavy Ion Collider at Brookhaven are reviewed. Their technical performance and the cost for the industry-built production dipoles are given. The cost data is generalized in order to extrapolate the cost of magnets for a new machine

  5. Can superconductivity be predicted with the aid of pattern recognition techniques

    International Nuclear Information System (INIS)

    Pijpers, F.W.

    1982-01-01

    Pattern recognition techniques were employed in order to investigate the possibility to find features of the elements of the periodic system that may be relevant for the description of their behaviour with respect to superconductivity. Learning machines were constructed using those elements of the periodic system whose superconducting properties have been well studied. Relevant features appear to be the electronic work function and the number of valence electrons as given by Miedema, the specific heat, the heat of melting, the heat of sublimation, the melting point and the atomic radius. The learning machines have a predicting capability of the order of 90%. The predictive power of these machines concerning the superconducting behaviour of the alkali and alkaline-earth metals belonging to a given test set, however, appears to be less convincing

  6. Development of 70 MW class superconducting generator with quick-response excitation

    Science.gov (United States)

    Miyaike, Kiyoshi; Kitajima, Toshio; Ito, Tetsuo

    2002-03-01

    The development of a superconducting generator had been carried out for 12 years under the first stage of a Super GM project. The 70 MW class model machine with quick response excitation was manufactured and evaluated in the project. This type of superconducting generator improves power system stability against rapid load fluctuations at the power system faults. This model machine achieved all development targets including high stability during rapid excitation control. It was also connected to the actual 77 kV electrical power grid as a synchronous condenser and proved advantages and high-operation reliability of the superconducting generator.

  7. Powering and Machine Protection of the Superconducting LHC Accelerator

    OpenAIRE

    Zerlauth, M; Schmidt, R

    2004-01-01

    A very large number of magnets, both superconducting and conventional copper conductor magnets, are installed in the LHC (Large Hadron Collider) for the guidance of the two proton beams around the circumference. In total, the LHC counts 1614 different electrical circuits with 1712 power converters for DC powering of the superconducting and normal conducting magnets. Besides the electrical circuits connecting main magnets for bending and focusing of the two counter-rotating beams, the demandin...

  8. Linear collider applications of superconducting RF

    International Nuclear Information System (INIS)

    Rubin, D.L.

    1990-01-01

    The most promising technology for producing interactions of electrons and positrons in TeV energy range is the linear collider. In the linear collider each and every collision of charged particles depends on the production of the charges at rest and then the acceleration of those charges to full energy. The particles that exit the interaction region are discharded. A consequence of this mode of operation is that the luminosity of the machine is ultimately determined by the efficiency with which AC power can be converted into beam power. The consideration of superconducting cavities is motivated by the need for high efficiency. Thus, the high emittance around a beam collider and low emittance around beams are discussed first in the present report. Flat beams are then addressed focusing on the characteristics of the source, final focus, and beam stability. The beam stability, in particular, is discussed in detail in relation to the multiple bunch transverse stability, wake field induced energy spread, trapped modes, pulse width, duty cycle, RF power, and refrigerator power. (N.K.)

  9. 56th (fiscal 1997) Meeting on Cryogenics and Superconductivity; Dai 56 kai 1997 nendo shunki teion kogaku chodendo gakkai koen gaiyoshu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-14

    In the meeting, 266 papers were made public which deal with the following fields: GM refrigerators, pulse tube refrigerators, cold storage equipment, Bi-2212 system, coil application, superconducting generators, LHD/ITER/accelerators, cable-in conduit conductors, electromagnetic phenomena/proximity effect, oxide cable, Nb3Sn, Nb3Al, metal materials, WE-NET, friction/organic materials, composite materials, Nb3Sn, Nb3Al wires, strand wire structure analysis, hybrid superconducting wire, Y system, Bi system, low temperature device, measurement, high magnetic field NMR magnet, oxide NMR application, Bi-2223 system wire, pinning, NbTi ac wire, pinning/ac loss, various characteristics, superconducting application, refrigerating system, heat transfer, cryostat, Hg/Ti/Y system wire, ac loss/application, superconducting electric power storage system and the development of element technology therefor, current limiter/magnetic flotation, stability and drift of strand conductors, stability, ITER, LHD/accelerator/SLIM, oxide application, conductor stability test and others, and quench of ac cable.

  10. A.C. losses in current-carrying superconductors

    International Nuclear Information System (INIS)

    Reuver, J.L. de.

    1985-01-01

    The feasibility of superconductors for alternating current use depends on successful reduction of losses. Moreover, the demand for large field amplitudes is a stimulation for investigating the nature of a.c. losses (e.g. in the set of poloidal coils in a TOKAMAK). In this thesis, measurements are performed at a.c. superconductivity. Attention is given to various external field conditions as well as to self-field instability. Measurements are performed on different types of wires. A type of wire is searched for with both low losses and a good stabilization under self-field conditions. (G.J.P.)

  11. Tore-Supra: a Tokamak with superconducting toroidal field coils

    International Nuclear Information System (INIS)

    Turck, B.

    1987-07-01

    Tore Supra is a tokamak under construction on the site of Cen Cadarache by the Euratom-CEA Association. The machine technology integrates all problems related to the fabrication and the operation of large superconducting coils and of the associated cryogenic system. Tore Supra will provide a significant experience to prepare the next generation of machines for plasma physics and controlled fusion. Tore Supra is specially designed to implement a large physics program. The superconducting coils make possible the study of plasma confinement in long pulses (more than 60s), the impurities and the stability, and the efficiency of additional heating sources (neutral particle beams and radio frequency heating). The opportunity is taken to recall the particular features and requirements of the superconducting coils of the large future tokamaks in order to point out the problems that have to be faced by any new material (superconducting or not)

  12. Powering and Machine Protection of the Superconducting LHC Accelerator

    CERN Document Server

    Zerlauth, M

    2004-01-01

    A very large number of magnets, both superconducting and conventional copper conductor magnets, are installed in the LHC (Large Hadron Collider) for the guidance of the two proton beams around the circumference. In total, the LHC counts 1614 different electrical circuits with 1712 power converters for DC powering of the superconducting and normal conducting magnets. Besides the electrical circuits connecting main magnets for bending and focusing of the two counter-rotating beams, the demanding requirements on the quality of the magnetic fields require a large number of circuits for corrector magnets distributed around the circumference. In total, more than 10000 magnets will need to be connected to the power converters via a large inventory of electrical components such as normal conducting cables and tubes, energy extraction systems, current feedthroughs and superconducting busbars. Depending on the complexity and importance of these electrical circuits and their components, various systems will interact for...

  13. Superconducting magnetic bearings for machine tools. Phase 1, SBIR program. Final report

    International Nuclear Information System (INIS)

    Anastas, G.; Bennett, A.; Downer, J.; Hockney, R.

    1988-01-01

    The research was directed toward investigating the role of superconducting materials in a magnetic bearing system. Superconducting magnetic bearings are shown to offer the potential for vastly improved performance. These bearings are expected to be especially applicable to rotors which have extremely tight position tolerances. The development of superconducting magnetic bearing technology is also expected to allow a number of novel approaches in the development of machinery and systems. Researchers studied an alternative bearing design which employs a superconducting coil and eliminates all conventional magnetic structures. The study has resulted in a design definition and detailed analysis for a superconducting bearing system which is sized to roughly duplicate the air bearing system of an existing air-bearing spindle

  14. A novel design of DC-AC electrical machine rotary converter for hybrid solar and wind energy applications

    International Nuclear Information System (INIS)

    Mohammed, K G; Ramli, A Q; Amirulddin, U A U

    2013-01-01

    This paper proposes the design of a new bi-directional DC-AC rotary converter machine to convert a d.c. voltage to three-phase voltage and vice-versa using a two-stage energy conversion machine. The rotary converter consists of two main stages which are combined into single frame. These two stages are constructed from three main electromagnetic components. The first inner electromagnetic component represents the input stage that enables the DC power generated by solar energy from photo-voltaic cells to be transformed by the second and third components electro-magnetically to produce multi-phase voltages at the output stage. At the same time, extra kinetic energy from wind, which is sufficiently available, can be added to existing torque on the second electromagnetic component. Both of these input energies will add up to the final energy generated at the output terminals. Therefore, the machine will be able to convert solar and wind energies to the output terminals simultaneously. If the solar energy is low, the available wind energy will be able to provide energy to the output terminals and at the same time charges the batteries which are connected as backup system. At this moment, the machine behaves as wind turbine. The energy output from the machine benefits from two energy sources which are solar and wind. At night when the solar energy is not available and also the load is low, the wind energy is able to charge the batteries and at the same time provides output electrical power to the remaining the load. Therefore, the proposed system will have high usage of available renewable energy as compared to separated wind or solar systems. MATLAB codes are used to calculate the required dimensions, the magnetic and electrical circuits parameters to design of the new bi-directional rotary converter machine.

  15. FY 1998 result report on development of superconductive power application technologies. Pt. 1. Research and development of superconductive wire materials / Research of a total system / Research and development of a freezing system / Demonstration tests; 1998 nendo chodendo denryoku oyo gijutsu kaihatsu. 1. Chodendo senzai no kenkyu kaihatsu, chodendo hatsudenki no kenkyu kaihatsu, total system no kenkyu, reito system no kenkyu kaihatsu, jissho shiken

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Superconductive technologies are introduced into electric power devices for attempts of achieving higher stabilization, density and efficiency, as well as size and weight reduction and improvement in performance of the devices. The project has been worked on since fiscal 1998 as part of the New Sunshine Project. Fiscal 1998 being the eleventh year has taken the following subjects as the research promotion policies: establishment of plans targeted at accomplishment of the goals of the project; adequate and reliable implementation of verification of technological assignments; and steady and efficient demonstration tests. Subsequent to the previous year during which site demonstration tests were completed on a low-speed responsive model machine, the site demonstration test has begun on the ultra high-speed responsive model machine as the final stage of the project. The ultra high-speed responsive model machine was coupled with a freezing system and a load synchronizing machine, and different kinds of test were carried out where good results were obtained. Researches were conducted on characteristics improvement and device element technologies aimed at achieving the practical application level by utilizing the respective features of AC metal-based wires and oxide-based wires, where sound results were obtained. Also in an improved freezing system, valuable data were attained as part of establishing the basic technologies for a superconductive power generation system. (NEDO)

  16. Superconducting magnets

    International Nuclear Information System (INIS)

    1994-08-01

    This report discusses the following topics on superconducting magnets: D19B and -C: The next steps for a record-setting magnet; D20: The push beyond 10 T: Beyond D20: Speculations on the 16-T regime; other advanced magnets for accelerators; spinoff applications; APC materials development; cable and cabling-machine development; and high-T c superconductor at low temperature

  17. Superconducting magnet activities at CEN Saclay

    International Nuclear Information System (INIS)

    Lesmond, C.

    1981-07-01

    The activities in superconducting magnets at DPhPE/Saclay spread over a wide range from DC magnets mainly for particle and nuclear physics and also for other fields of research, pulsed magnets for particle accelerators and for a controlled fusion tokamak machine. The superconducting magnets designed during recent years involve a variety of conductor types, winding schemes, materials and cooling modes, including the use of superfluid helium. (author)

  18. Nuclear Structure Effects in the Exotic Decay of $^{225}$Ac via $^{14}$C Emission

    CERN Multimedia

    2002-01-01

    % IS323 \\\\ \\\\ We propose to build at Isolde a high intensity $^{225}$Ac source by $\\beta$-decay of $^{225}$(Ra+Fr) beam, to be used at the superconducting spectrometer SOLENO of IPN-Orsay in order to study a possible fine structure in the spectrum of $^{14}$C ions spontaneously emitted by $^{225}$Ac.

  19. Nonlinear AC susceptibility, surface and bulk shielding

    Science.gov (United States)

    van der Beek, C. J.; Indenbom, M. V.; D'Anna, G.; Benoit, W.

    1996-02-01

    We calculate the nonlinear AC response of a thin superconducting strip in perpendicular field, shielded by an edge current due to the geometrical barrier. A comparison with the results for infinite samples in parallel field, screened by a surface barrier, and with those for screening by a bulk current in the critical state, shows that the AC response due to a barrier has general features that are independent of geometry, and that are significantly different from those for screening by a bulk current in the critical state. By consequence, the nonlinear (global) AC susceptibility can be used to determine the origin of magnetic irreversibility. A comparison with experiments on a Bi 2Sr 2CaCu 2O 8+δ crystal shows that in this material, the low-frequency AC screening at high temperature is mainly due to the screening by an edge current, and that this is the unique source of the nonlinear magnetic response at temperatures above 40 K.

  20. Applied superconductivity. Handbook on devices and applications. Vol. 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Paul (ed.) [Jena Univ. (Germany). Inst. fuer Festkoerperphysik, AG Tieftemperaturphysik

    2015-07-01

    The both volumes contain the following 12 chapters: 1. Fundamentals; 2. Superconducting Materials; 3. Technology, Preparation, and Characterization (bulk materials, thin films, multilayers, wires, tapes; cooling); 4, Superconducting Magnets; 5. Power Applications (superconducting cables, superconducting current leads, fault current limiters, transformers, SMES and flywheels; rotating machines; SmartGrids); 6. Superconductive Passive Devices (superconducting microwave components; cavities for accelerators; superconducting pickup coils; magnetic shields); 7. Applications in Quantum Metrology (superconducting hot electron bolometers; transition edge sensors; SIS Mixers; superconducting photon detectors; applications at Terahertz frequency; detector readout); 8. Superconducting Radiation and Particle Detectors; 9. Superconducting Quantum Interference (SQUIDs); 10. Superconductor Digital Electronics; 11. Other Applications (Josephson arrays as radiation sources. Tunable microwave devices) and 12. Summary and Outlook (of the superconducting devices).

  1. Applied superconductivity. Handbook on devices and applications. Vol. 1 and 2

    International Nuclear Information System (INIS)

    Seidel, Paul

    2015-01-01

    The both volumes contain the following 12 chapters: 1. Fundamentals; 2. Superconducting Materials; 3. Technology, Preparation, and Characterization (bulk materials, thin films, multilayers, wires, tapes; cooling); 4, Superconducting Magnets; 5. Power Applications (superconducting cables, superconducting current leads, fault current limiters, transformers, SMES and flywheels; rotating machines; SmartGrids); 6. Superconductive Passive Devices (superconducting microwave components; cavities for accelerators; superconducting pickup coils; magnetic shields); 7. Applications in Quantum Metrology (superconducting hot electron bolometers; transition edge sensors; SIS Mixers; superconducting photon detectors; applications at Terahertz frequency; detector readout); 8. Superconducting Radiation and Particle Detectors; 9. Superconducting Quantum Interference (SQUIDs); 10. Superconductor Digital Electronics; 11. Other Applications (Josephson arrays as radiation sources. Tunable microwave devices) and 12. Summary and Outlook (of the superconducting devices).

  2. A two-phase full-wave superconducting rectifier

    International Nuclear Information System (INIS)

    Ariga, T.; Ishiyama, A.

    1989-01-01

    A two-phase full-wave superconducting rectifier has been developed as a small cryogenic power supply of superconducting magnets for magnetically levitation trains. Those magnets are operated in the persistent current mode. However, small ohmic loss caused at resistive joints and ac loss induced by the vibration of the train cannot be avoided. Therefore, the low-power cryogenic power supply is required to compensate for the reduction in magnet current. The presented superconducting rectifier consists of two identical full-wave rectifiers connected in series. Main components of each rectifier are a troidal shape superconducting set-up transformer and two thermally controlled switches. The test results using a 47.5 mH load magnet at 0.2 Hz and 0.5 Hz operations are described. To estimate the characteristics of the superconducting rectifier, the authors have developed a simulation code. From the experiments and the simulations, the transfer efficiency is examined. Furthermore, the optimal design of thermally controlled switches based on the finite element analysis is also discussed

  3. Reluctance motor employing superconducting magnetic flux switches

    International Nuclear Information System (INIS)

    Spyker, R.L.; Ruckstadter, E.J.

    1992-01-01

    This paper reports that superconducting flux switches controlling the magnetic flux in the poles of a motor will enable the implementation of a reluctance motor using one central single phase winding. A superconducting flux switch consists of a ring of superconducting material surrounding a ferromagnetic pole of the motor. When in the superconducting state the switch will block all magnetic flux attempting to flow in the ferromagnetic core. When switched to the normal state the superconducting switch will allow the magnetic flux to flow freely in that pole. By using one high turns-count coil as a flux generator, and selectively channeling flux among the various poles using the superconducting flux switch, 3-phase operation can be emulated with a single-hase central AC source. The motor will also operate when the flux generating coil is driven by a DC current, provided the magnetic flux switches see a continuously varying magnetic flux. Rotor rotation provides this varying flux due to the change in stator pole inductance it produces

  4. AC Transport Current Loss in a Coated Superconductor in the Bean Model

    National Research Council Canada - National Science Library

    Carr, Jr, W. J

    2004-01-01

    A new and straightforward calculation is made of the loss in a very thin superconducting strip of rectangular cross section carrying ac transport current in zero applied magnetic field, with a similar...

  5. Superconducting magnetic energy storage (SMES) program, January 1-December 31, 1981

    International Nuclear Information System (INIS)

    Rogers, J.D.

    1982-02-01

    Work reported is on the development of a 30 MJ superconducting magnetic energy storage (SMES) unit for use by the Bonneville Power Administration (BPA) to stabilize power oscillations on their Pacific AC Intertie. The 30 MJ superconducting coil manufacture was completed. Design of the seismic mounting of the coil to the nonconducting dewar lid and a concrete foundation is complete. The superconducting application VAR (SAVAR) control study indicated a low economic advantage and the SAVAR program was terminated. An economic and technological evaluation of superconducting fault current limiter (SFCL) was completed and the results are reported

  6. Iron-YBCO heterostructures and their application for trapped field superconducting motor

    Energy Technology Data Exchange (ETDEWEB)

    Granados, X [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus U.A. Barcelona, 08193 Bellaterra (Spain); Bartolome, E [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus U.A. Barcelona, 08193 Bellaterra (Spain); Obradors, X [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus U.A. Barcelona, 08193 Bellaterra (Spain); Tornes, M [ETSE-UAB, Barcelona (Spain); Rodrigues, L [UNL, Lisbon (Portugal); Gawalek, W [IPHT, Jena (Germany); McCulloch, M [Department Engineering Science, University of Oxford, Oxford (United Kingdom); Hughes, D Dew [Department Engineering Science, University of Oxford, Oxford (United Kingdom); Campbell, A [IRC-UCAM, Cambridge (United Kingdom); Coombs, T [IRC-UCAM, Cambridge (United Kingdom); Ausloos, M [SUPRATEC, Liege (Belgium); Cloots, R [SUPRATEC, Liege (Belgium)

    2006-06-01

    In this work we report on the magnetic behavior of the heterostructures formed by bulk based YBCO rings and ferromagnetic yoke. The magnetization cycle has been performed by an In-Field Hall Mapping technique. A video-like recording of the magnetization process makes it possible to obtain the magnetization of selected areas. The current flowing through the superconducting rings can be deduced from the magnetic field maps. The displacement of the peak of magnetization due to the flux reversal produced by the magnetization of the yoke is also considered. These hybrid heterostructures formed by ferromagnetic and superconducting material have been applied in the construction of the rotor for a brushless AC motor. The design and construction of this machine was carried out within the framework of the TMR Network SUPERMACHINES. The rotor has been designed in a quadrupolar configuration by cutting large YBCO 'window frames' from seeded melt-textured single domain YBCO pellets. This rotor has been coupled to a conventional stator of copper coils wound on an iron armature. The stator can be excited both in bipolar or quadrupolar mode. We report on the behaviour of the motor after a field cooling process when excited in quadrupolar mode.

  7. Study on the flow reduction of forced flow superconducting magnet and its stable operation condition

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Makoto [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2001-03-01

    The forced flow superconducting coil especially made from a Cable-in-Conduit Conductor (CICC) is applied for large-scale devices such as fusion magnets and superconducting magnet energy storage (SMES) because it has high mechanical and electrical performance potential. The flow reduction phenomena caused by AC loss generation due to the pulsed operation was found based on the experimental results of three forced flow superconducting coils. And relation between the AC loss generation and flow reduction was defined from viewpoint of the engineering design and operation of the coils. Also the mechanism of flow reduction was investigated and stable operation condition under the flow reduction was clarified for forced flow superconducting coils. First, experiments of three different large-scale superconducting coils were carried out and experimental database of the flow reduction by AC loss generation was established. It was found experimentally that the flow reduction depends on the AC loss generation (W/m{sup 3}) in all of coils. It means the stable operation condition is defined not only the electro magnetism of superconducting coil but also flow condition. Mechanism of the flow reduction was investigated based on the experimental database. Hydraulics was applied to supercritical helium as a coolant. Also performances of the cryogenic pump by which coolant are supplied to the coil and friction of the superconductor as cooling path is considered for hydraulic estimation. The flow reduction of the coil is clarified and predictable by the equations of continuity, momentum and energy balance. Also total mass flow rate of coolant was discussed. The estimation method in the design phase was developed for total mass flow rate which are required under the flow reduction by AC losses. The friction of the superconductor and performance of cryogenic pump should be required for precise prediction of flow reduction. These values were obtained by the experiment data of coil and

  8. Operational experience with superconducting synchrotron magnets

    International Nuclear Information System (INIS)

    Martin, P.S.

    1987-01-01

    The operational experience with the Fermilab Tevatron is presented, with emphasis on reliability and failure modes. Comparisons are made between the operating efficiencies for the superconducting machine and for the conventional Main Ring

  9. Operational experience with superconducting synchrotron magnets

    International Nuclear Information System (INIS)

    Martin, P.S.

    1987-03-01

    The operational experience with the Fermilab Tevatron is presented, with emphasis on reliability and failure modes. Comprisons are made between the operating efficiencies for the superconducting machine and for he conventional Main Ring

  10. Comparison of 10 MW superconducting generator topologies for direct-drive wind turbines

    DEFF Research Database (Denmark)

    Liu, Dong; Polinder, Henk; Abrahamsen, Asger Bech

    2015-01-01

    Large wind turbines of 10 MW or higher power levels are desirable for reducing the cost of energy of offshore wind power conversion. Conventional wind generator systems will be costly if scaled up to 10 MW due to rather large size and weight. Direct drive superconducting generators have been...... magnetic field excitation allows for lightweight non-magnetic composite materials for machine cores instead of iron. A topology would probably not be a good option for an offshore wind turbine generator if it demands a far more expensive active material cost than others, even if it has other advantages...... proposed to address the problem with generator size, because the electrical machines with superconducting windings are capable of achieving a higher torque density of an electrical machine. However, the topology to be adopted for superconducting wind generators has not yet been settled, since the high...

  11. Adaptability of optimization concept in the context of cryogenic distribution for superconducting magnets of fusion machine

    Science.gov (United States)

    Sarkar, Biswanath; Bhattacharya, Ritendra Nath; Vaghela, Hitensinh; Shah, Nitin Dineshkumar; Choukekar, Ketan; Badgujar, Satish

    2012-06-01

    Cryogenic distribution system (CDS) plays a vital role for reliable operation of largescale fusion machines in a Tokamak configuration. Managing dynamic heat loads from the superconducting magnets, namely, toroidal field, poloidal field, central solenoid and supporting structure is the most important function of the CDS along with the static heat loads. Two concepts are foreseen for the configuration of the CDS: singular distribution and collective distribution. In the first concept, each magnet is assigned with one distribution box having its own sub-cooler bath. In the collective concept, it is possible to share one common bath for more than one magnet system. The case study has been performed with an identical dynamic heat load profile applied to both concepts in the same time domain. The choices of a combined system from the magnets are also part of the study without compromising the system functionality. Process modeling and detailed simulations have been performed for both the options using Aspen HYSYS®. Multiple plasma pulses per day have been considered to verify the residual energy deposited in the superconducting magnets at the end of the plasma pulse. Preliminary 3D modeling using CATIA® has been performed along with the first level of component sizing.

  12. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    Science.gov (United States)

    Kajikawa, K.; Funaki, K.; Shikimachi, K.; Hirano, N.; Nagaya, S.

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean's critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  13. Shunt protection for superconducting Maglev magnets

    Energy Technology Data Exchange (ETDEWEB)

    Atherton, D L [Queen' s Univ., Kingston, Ontario (Canada). Dept. of Physics

    1979-09-01

    Closely coupled, short-circuited shunt coils are proposed for quench protection of superconducting Maglev magnets which use high resistance, matrix composite conductors. It is shown that, by suitable design, the shunts can reduce induced ac losses and that the changing currents during magnet energization or vehicle lift off and landing can be tolerated.

  14. Research on superconducting generator and materials in Japan

    International Nuclear Information System (INIS)

    Uyeda, K.; Maki, N.; Kurihara, S.; Ueda, A.; Hirose, S.; Itoh, K.

    1988-01-01

    As a first step of application of superconducting technology to electric power equipment, the practical use of superconducting generator is sucessfully developed, enhanced generation efficiency, reduced construction cost, improved stability limit. For the development, it is required to integrated such technical assets as new generator design technology based on detailed analysis of techniques and high strength material for with standing intensive electro-magnetic force. This paper describes history and results of research and development of superconducting generator for experimental machines, the results of feasibility study of pilot generator, and master plan for research and development of superconducting technology for applications to generator and the other power apparatus

  15. Once upon a time, there was a brittle but superconducting niobium-tin…

    CERN Multimedia

    Stefania Pandolfi

    2016-01-01

    The production of the new niobium-tin cables for the high-performance superconducting magnets of the HL-LHC is now in full swing at CERN.   The Rutherford cabling machine is operating in the superconducting laboratory, in Building 163. (Photo: Max Brice/CERN) Extraordinary research needs extraordinary machines: the upgrade project of the LHC, the High-Luminosity LHC (HL-LHC), has the goal of achieving instantaneous luminosities a factor of five larger than the LHC nominal value, and it relies on magnetic fields reaching the level of 12 Tesla. The superconducting niobium-titanium (Nb-Ti) used in the LHC magnets can only bear magnetic fields of up to 9-10 Tesla. Therefore, an alternative solution for the superconducting magnets materials was needed. The key innovative technology to develop superconducting magnets beyond 10 Tesla has been found in the niobium-tin (Nb3Sn)  compound. This compound was actually discovered in 1954, eight years before Nb-Ti, but when the LHC was built, ...

  16. Transport ac loss studies of YBCO coated conductors with nickel alloy substrates

    International Nuclear Information System (INIS)

    Duckworth, R C; Thompson, J R; Gouge, M J; Lue, J W; Ijaduola, A O; Yu, D; Verebelyi, D T

    2003-01-01

    Transport alternating current (ac) loss measurements were performed on a series of rolling-assisted biaxially textured substrate (RABiTS) processed YBa 2 Cu 3 O x (YBCO) coated conductors at 77 K. While each sample possessed a 1 μm layer of YBCO and a 3 μm silver cap layer, two different nickel alloy substrates were used and their impact on the ac loss was examined. Both substrates possessed a 75 μm Ni-5 at%W base, but one substrate also had a 2 μm nickel overlayer as part of the buffer layer architecture. The ac losses, which were determined by thermal and electrical measurements, contained two dominant contributions: superconductive hysteresis in the YBCO and ferromagnetic hysteresis in the substrates. The superconductive component followed the Norris elliptic model for the substrate with the nickel overlayer and the Norris thin strip model for the substrate without the nickel overlayer. The substrates' ferromagnetic loss was determined separately through magnetization measurements, which showed that this loss contribution was independent of the presence of the nickel overlayer for effective ac currents less than 50 A. While the overall loss was lower for the thin-strip-like conductor with no nickel overlayer, further research is necessary to strengthen this connection

  17. A numerical study on the feasibility evaluation of a hybrid type superconducting fault current limiter applying thyristors

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Seok Ho; Lee, Woo Seung; Lee, Ji Ho; Hwang, Young Jin; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of)

    2013-12-15

    Smart fault current controller (SFCC) proposed in our previous work consists of a power converter, a high temperature superconducting (HTS) DC reactor, thyristors, and a control unit [1]. SFCC can limit and control the current by adjusting firing angles of thyristors when a fault occurs. SFCC has complex structure because the HTS DC reactor generates the loss under AC. To use the DC reactor under AC, rectifier that consists of four thyristors is needed and it increases internal resistance of SFCC. For this reason, authors propose a hybrid type superconducting fault current limiter (SFCL). The hybrid type SFCL proposed in this paper consists of a non-inductive superconducting coil and two thyristors. To verify the feasibility of the proposed hybrid type SFCL, simulations about the interaction of the superconducting coil and thyristors are conducted when fault current flows in the superconducting coil. Authors expect that the hybrid type SFCL can control the magnitude of the fault current by adjusting the firing angles of thyristors after the superconducting coil limits the fault current at first peak.

  18. A numerical study on the feasibility evaluation of a hybrid type superconducting fault current limiter applying thyristors

    International Nuclear Information System (INIS)

    Nam, Seok Ho; Lee, Woo Seung; Lee, Ji Ho; Hwang, Young Jin; Ko, Tae Kuk

    2013-01-01

    Smart fault current controller (SFCC) proposed in our previous work consists of a power converter, a high temperature superconducting (HTS) DC reactor, thyristors, and a control unit [1]. SFCC can limit and control the current by adjusting firing angles of thyristors when a fault occurs. SFCC has complex structure because the HTS DC reactor generates the loss under AC. To use the DC reactor under AC, rectifier that consists of four thyristors is needed and it increases internal resistance of SFCC. For this reason, authors propose a hybrid type superconducting fault current limiter (SFCL). The hybrid type SFCL proposed in this paper consists of a non-inductive superconducting coil and two thyristors. To verify the feasibility of the proposed hybrid type SFCL, simulations about the interaction of the superconducting coil and thyristors are conducted when fault current flows in the superconducting coil. Authors expect that the hybrid type SFCL can control the magnitude of the fault current by adjusting the firing angles of thyristors after the superconducting coil limits the fault current at first peak.

  19. The Superconducting Super Collider: A status report

    International Nuclear Information System (INIS)

    Schwitters, R.F.

    1993-04-01

    The design of the Superconducting Super Collider (SSC) is briefly reviewed, including its key machine parameters. The scientific objectives are twofold: (1) investigation of high-mass, low-rate, rare phenomena beyond the standard model; and (2) investigation of processes within the domain of the standard model. Machine luminosity, a key parameter, is a function of beam brightness and current, and it must be preserved through the injector chain. Features of the various injectors are discussed. The superconducting magnet system is reviewed in terms of model magnet performance, including the highly successful Accelerator System String Test Various magnet design modifications are noted, reflecting minor changes in the collider arcs and improved installation procedures. The paper concludes with construction scenarios and priority issues for ensuring the earliest collider commissioning

  20. Shunt protection for superconducting Maglev magnets

    International Nuclear Information System (INIS)

    Atherton, D.L.

    1979-01-01

    Closely coupled, short-circuited shunt coils are proposed for quench protection of superconducting Maglev magnets which use high resistance, matrix composite conductors. It is shown that, by suitable design, the shunts can reduce induced ac losses and that the changing currents during magnet energization or vehicle lift off and landing can be tolerated. (author)

  1. The present role of superconductivity in fusion

    International Nuclear Information System (INIS)

    Shimamoto, S.

    1986-01-01

    After completion of large fusion devices in the world, such as JT-60, JET and TFTR, high temperature plasma is proceeding to critical condition for fusion. The devices up to now use mainly conventional magnet. However, for the next generation machine which demonstrates fusion reaction, deuterium-tritium burning, superconducting magnet system is indispensable from view point of both net energy extraction and capacity limitation of power supply. In order to realize such a large and complicated system, a lot of development works is being carried out. This paper describes required parameters of superconducting magnet and helium refrigerator, the state of plasma condition and superconducting magnet. It is shown that the present technology of superconducting magnet is not so far from realization of fusion experimental reactor

  2. Direct amplitude detuning measurement with ac dipole

    Directory of Open Access Journals (Sweden)

    S. White

    2013-07-01

    Full Text Available In circular machines, nonlinear dynamics can impact parameters such as beam lifetime and could result in limitations on the performance reach of the accelerator. Assessing and understanding these effects in experiments is essential to confirm the accuracy of the magnetic model and improve the machine performance. A direct measurement of the machine nonlinearities can be obtained by characterizing the dependency of the tune as a function of the amplitude of oscillations (usually defined as amplitude detuning. The conventional technique is to excite the beam to large amplitudes with a single kick and derive the tune from turn-by-turn data acquired with beam position monitors. Although this provides a very precise tune measurement it has the significant disadvantage of being destructive. An alternative, nondestructive way of exciting large amplitude oscillations is to use an ac dipole. The perturbation Hamiltonian in the presence of an ac dipole excitation shows a distinct behavior compared to the free oscillations which should be correctly taken into account in the interpretation of experimental data. The use of an ac dipole for direct amplitude detuning measurement requires careful data processing allowing one to observe the natural tune of the machine; the feasibility of such a measurement is demonstrated using experimental data from the Large Hadron Collider. An experimental proof of the theoretical derivations based on measurements performed at injection energy is provided as well as an application of this technique at top energy using a large number of excitations on the same beam.

  3. AC electric motors control advanced design techniques and applications

    CERN Document Server

    Giri, Fouad

    2013-01-01

    The complexity of AC motor control lies in the multivariable and nonlinear nature of AC machine dynamics. Recent advancements in control theory now make it possible to deal with long-standing problems in AC motors control. This text expertly draws on these developments to apply a wide range of model-based control designmethods to a variety of AC motors. Contributions from over thirty top researchers explain how modern control design methods can be used to achieve tight speed regulation, optimal energetic efficiency, and operation reliability and safety, by considering online state var

  4. Free electron lasers on superconducting linac

    International Nuclear Information System (INIS)

    Lapierrre, Y.

    1986-01-01

    Analysing the results of several Free Electron Laser experiments, we show that the best accelerator should be a superconducting linear accelerator: it can provide a c.w. high quality beam (energy spread and emittance). The technology of RF superconductivity provide the opportunity to build such an accelerator. In this paper, we present the foreseen results one can expect from a FEL based on such a machine: - Average power > 1 Kw, - Total efficiency > 2.5%, - Tunability between 0.6 and 5 μm [fr

  5. High-temperature superconducting conductors and cables

    International Nuclear Information System (INIS)

    Peterson, D.E.; Maley, M.P.; Boulaevskii, L.; Willis, J.O.; Coulter, J.Y.; Ullmann, J.L.; Cho, Jin; Fleshler, S.

    1996-01-01

    This is the final report of a 3-year LDRD project at LANL. High-temperature superconductivity (HTS) promises more efficient and powerful electrical devices such as motors, generators, and power transmission cables; however this depends on developing HTS conductors that sustain high current densities J c in high magnetic fields at temperatures near liq. N2's bp. Our early work concentrated on Cu oxides but at present, long wire and tape conductors can be best made from BSCCO compounds with high J c at low temperatures, but which are degraded severely at temperatures of interest. This problem is associated with thermally activated motion of magnetic flux lines in BSCCO. Reducing these dc losses at higher temperatures will require a high density of microscopic defects that will pin flux lines and inhibit their motion. Recently it was shown that optimum defects can be produced by small tracks formed by passage of energetic heavy ions. Such defects result when Bi is bombarded with high energy protons. The longer range of protons in matter suggests the possibility of application to tape conductors. AC losses are a major limitation in many applications of superconductivity such as power transmission. The improved pinning of flux lines reduces ac losses, but optimization also involves other factors. Measuring and characterizing these losses with respect to material parameters and conductor design is essential to successful development of ac devices

  6. Demonstration of superconducting micromachined cavities

    Energy Technology Data Exchange (ETDEWEB)

    Brecht, T., E-mail: teresa.brecht@yale.edu; Reagor, M.; Chu, Y.; Pfaff, W.; Wang, C.; Frunzio, L.; Devoret, M. H.; Schoelkopf, R. J. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)

    2015-11-09

    Superconducting enclosures will be key components of scalable quantum computing devices based on circuit quantum electrodynamics. Within a densely integrated device, they can protect qubits from noise and serve as quantum memory units. Whether constructed by machining bulk pieces of metal or microfabricating wafers, 3D enclosures are typically assembled from two or more parts. The resulting seams potentially dissipate crossing currents and limit performance. In this letter, we present measured quality factors of superconducting cavity resonators of several materials, dimensions, and seam locations. We observe that superconducting indium can be a low-loss RF conductor and form low-loss seams. Leveraging this, we create a superconducting micromachined resonator with indium that has a quality factor of two million, despite a greatly reduced mode volume. Inter-layer coupling to this type of resonator is achieved by an aperture located under a planar transmission line. The described techniques demonstrate a proof-of-principle for multilayer microwave integrated quantum circuits for scalable quantum computing.

  7. Superconducting DC homopolar motors for ship propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Heiberger, M.; Reed, M.R.; Creedon, W.P.; O' Hea, B.J. [General Atomic (United States)

    2000-07-01

    Superconducting DC homopolar motors have undergone recent advances in technology, warranting serious consideration of their use for ship propulsion. Homopolar motor propulsion is now practical because of two key technology developments: cryogen-free superconducting refrigeration and high performance motor fiber brushes. These compact motors are ideal for podded applications, where reduced drag and fuel consumption are predicted. In addition, the simple DC motor controller is more efficient and reliable compared with AC motor controllers. Military ships also benefit from increased stealth implicit in homopolar DC excitation, which also allows the option for direct hull or pod mounting. (authors)

  8. Anisotropic superconductivity in β-(BDA-TTP)2SbF6: STM spectroscopy

    Science.gov (United States)

    Nomura, K.; Muraoka, R.; Matsunaga, N.; Ichimura, K.; Yamada, J.

    2009-03-01

    We have investigated the gap symmetry in the superconducting phase of β-(BDA-TTP)2SbF6 with use of the scanning tunneling microscope (STM). The tunneling spectra obtained on the conducting surface show a clear superconducting gap structure. Its functional form is of V-shaped similarly to κ-(BEDT-TTF)2X and suggests the anisotropic superconducting gap with line nodes. For lateral surfaces the shape of tunneling spectra varies from the U-shape with relatively large gap to the V-shape with small gap depending on the tunneling direction alternately twice between directional angle 0 and π. From the analysis of conductance curve taking the k dependence of the tunneling probability into account, it is found that the gap has maximum near the a* and c* axes and the nodes appear along near a*+c* and the a-c* directions. These indicate that the d like superconducting pair is formed in this system as the case of κ-(BEDT-TTF)2X. This node direction is consistent with the theoretical prediction based on the spin fluctuation mechanism. However, the zero-bias conductance peak has not been observed yet.

  9. Anisotropic superconductivity in β-(BDA-TTP)2SbF6: STM spectroscopy

    International Nuclear Information System (INIS)

    Nomura, K.; Muraoka, R.; Matsunaga, N.; Ichimura, K.; Yamada, J.

    2009-01-01

    We have investigated the gap symmetry in the superconducting phase of β-(BDA-TTP) 2 SbF 6 with use of the scanning tunneling microscope (STM). The tunneling spectra obtained on the conducting surface show a clear superconducting gap structure. Its functional form is of V-shaped similarly to κ-(BEDT-TTF) 2 X and suggests the anisotropic superconducting gap with line nodes. For lateral surfaces the shape of tunneling spectra varies from the U-shape with relatively large gap to the V-shape with small gap depending on the tunneling direction alternately twice between directional angle 0 and π. From the analysis of conductance curve taking the k dependence of the tunneling probability into account, it is found that the gap has maximum near the a* and c* axes and the nodes appear along near a*+c* and the a-c* directions. These indicate that the d x 2 -y 2 like superconducting pair is formed in this system as the case of κ-(BEDT-TTF) 2 X. This node direction is consistent with the theoretical prediction based on the spin fluctuation mechanism. However, the zero-bias conductance peak has not been observed yet

  10. Pulse excitation experiment of a superconducting generator; chodendo hatsudenki no parusu reiki shiken

    Energy Technology Data Exchange (ETDEWEB)

    Miyaike, K.; Iimura, T.; Nishimura, M.; Arata, M.; Takabatake, M. [Toshiba Ltd., Tokyo (Japan); Yamada, M.; Kanamori, Y.; Hasegawa, K. [Kansai Electric Power Co., Inc., Osaka (Japan)

    1999-11-10

    Efficiency improvement, improvement in the stability of electric power system it is miniaturization and weight reduction can be expected in comparison with the traditional-model generator superconducting generator. We produce the small superconducting generator for the experiment experimentally, and performance characteristics verification of the generator is carried out experimentally. This time, pulse excitation test of the superconducting generator was carried out, and the ac loss of the conductor by the pulse excitation investigated the effect on the quenching current. (NEDO)

  11. On the Application of TLS Techniques to AC Electrical Drives

    Directory of Open Access Journals (Sweden)

    M. Cirrincione

    2005-03-01

    Full Text Available This paper deals with the application of a new neuron, the TLS EXIN neuron, to AC induction motor drives. In particular, it addresses two important subjects of AC induction motor drives: the on-line estimation of the electrical parameters of the machine and the speed estimation in sensorless drives. On this basis, this work summarizes the parameter estimation and sensorless techniques already developed by the authors over these last few years, all based on the TLS EXIN. With regard to sensorless, two techniques are proposed: one based on the MRAS and the other based on the full-order Luenberger observer. The work show some of the most significant results obtained by the authors in these fields and stresses the important potentiality of this new neural technique in AC induction machine drives.

  12. 78 FR 28577 - Notification of Proposed Production Activity: Whirlpool Corporation Subzone 8I; (Washing Machines...

    Science.gov (United States)

    2013-05-15

    ... machine parts to the list of approved finished products and would also add imported components to the...; refrigeration parts; dishwashing machine parts; drying machine parts; water inlet valves; AC/DC fan motors; AC... Activity: Whirlpool Corporation Subzone 8I; (Washing Machines): Clyde and Green Springs, Ohio Whirlpool...

  13. Design of a 10 MJ fast discharging homopolar machine

    International Nuclear Information System (INIS)

    Stillwagon, R.E.; Thullen, P.

    1977-01-01

    The design of a fast discharging homopolar machine is described. The machine capacity is 10 MJ with a 30 ms energy delivery time. The salient features of the machine are relatively high terminal voltage, fast discharge time, high power density and high efficiency. The machine integrates several new technologies including high surface speeds, large superconducting magnets and current collection at high density

  14. EAST machine assembly and its measurement system

    International Nuclear Information System (INIS)

    Wu, S.T.

    2005-01-01

    The EAST (HT-7U) superconducting tokamak consists of a superconducting poloidal field magnet system, a toroidal field magnet system, a vacuum vessel and in-vessel components, thermal shields and a cryostat vessel. The main parts of the machine have been delivered to ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences) successionally from 2003. For its complicated constitution and precise requirement, a reasonable assembly procedure and measurement technique should be defined carefully. Before the assembly procedure, a reference frame has been set up with reference fiducial targets on the wall of the test hall by an industrial measurement system. After the torus of TF coils is formed, a new reference frame will be set up from the position of the TF torus. The vacuum vessel with all inner parts will be installed with reference of the new reference frame. The big size and mass of components, special configuration of the superconducting machine with tight installation tolerances of the HT-7U (EAST) machine result in complicated assembly procedure. The procedure had begun with the installation of the support frame and the base of cryostat vessel last year. In this paper, the requirements of the assembly precise for some key components of the machine are described. The reference frame for the assembly and maintenance is explained. The assembly procedure is introduced

  15. Active superconducting DC fault current limiter based on flux compensation

    International Nuclear Information System (INIS)

    Shi Jing; Tang Yuejin; Wang, Chen; Zhou Yusheng; Li Jingdong; Ren Li; Chen Shijie

    2006-01-01

    With the extensive application of DC power systems, suppression of DC fault current is an important subject that guarantees system security. This paper presents an active superconducting DC fault current limiter (DC-SFCL) based on flux compensation. The DC-SFCL is composed of two superconducting windings wound on a single iron core, the primary winding is in series with DC power system, and the second winding is connected with AC power system through a PWM converter. In normal operating state, the flux in the iron core is compensated to zero, and the SFCL has no influence on DC power system. In the case of DC system accident, through regulating the active power exchange between the SFCL's second winding and the AC power system, the current on the DC side can be limited to different level complying with the system demand. Moreover, the PWM converter that interface the DC system and AC system can be controlled as a reactive power source to supply voltage support for the AC side, which has little influence on the performance of SFCL. Using MATLAB SIMULINK, the mathematic model of the DC-SFCL is created, simulation results validate the dynamics of system, and the performance of DC-SFCL is confirmed

  16. Potential damage to dc superconducting magnets due to high frequency electromagnetic waves

    Science.gov (United States)

    Gabriel, G. J.; Burkhart, J. A.

    1977-01-01

    Studies of a d.c. superconducting magnet coil indicate that the large coil behaves as a straight waveguide structure. Voltages between layers within the coil sometimes exceeded those recorded at terminals where protective resistors are located. Protection of magnet coils against these excessive voltages could be accomplished by impedance matching throughout the coil system. The wave phenomenon associated with superconducting magnetic coils may create an instability capable of converting the energy of a quiescent d.c. superconducting coil into dissipative a.c. energy, even in cases when dielectric breakdown does not take place.

  17. High-pressure effects on the superconductivity of β-pyrochlore oxides AOs2O6

    International Nuclear Information System (INIS)

    Muramatsu, Takaki; Takeshita, Nao; Terakura, Chikeko; Takagi, Hidenori; Tokura, Yoshinori; Yonezawa, Shigeki; Muraoka, Yuji; Hiroi, Zenji

    2006-01-01

    High-pressure effects on the superconducting transitions of β-pyrochlore oxide superconductors AOs 2 O 6 (A=Cs, Rb, K) are studied by measuring resistivity under high pressures up to 16 GPa. The superconducting transition temperature T c first increases with increasing pressure in all the compounds and then exhibits a broad maximum at 7.6 K (6 GPa), 8.2 K (2 GPa) and 10 K (0.6 GPa) for A=Cs, Rb and K, respectively. Finally, the superconductivity is suppressed completely at a critical pressure near 7 and 6 GPa for A=Rb and K and probably above 10 GPa for A=Cs. Characteristic changes in the temperature dependence of resistivity of RbOs 2 O 6 under high pressure. The residual resistivity largely increases with pressure above 4 GPa and, as a result, resistivity indicates small temperature dependence down to 4.2 K at 7 GPa and application of further pressure up to 10 GPa indicates that temperature dependence of resistivity decrease below 100 K. This characteristic behavior in the β-pyrochlore oxides may originate from the nesting of nearly octahedron shape of Fermi surface

  18. Alternative designs of a superconducting synchronous generator: the Southampton approach

    OpenAIRE

    Goddard, K.F.; Lukasik, B.; Sykulski, J.K.

    2008-01-01

    The paper describes various designs undertaken at the University of Southampton for building both cored and coreless superconducting synchronous generators using high temperature superconducting (HTS) tapes. An overview of electromagnetic and mechanical design issues is presented and scalability is considered. Results are included for the full (original) size machine and extended to a double size unit.

  19. Design of a low temperature superconducting coil to be applied to current regulators

    International Nuclear Information System (INIS)

    Garcia-Tabares, L.; Grau Carles, A

    1998-05-01

    We study the magnetic design and the cryogenic stability of a superconducting coil cooled with liquid helium, which works both in DC and AC modes. In DC mode, we obtain the maximum quench current; while in AC mode, we analyze Joule losses produced by the superconductor magnetization and the generation of eddy currents inside the copper matrix. (Author)

  20. The effect of ac magnetic fields on the lifting power of levitating superconductors

    International Nuclear Information System (INIS)

    Smolyak, B M; Ermakov, G V; Chubraeva, L I

    2007-01-01

    This study deals with the decrease in the levitation force under the action of an ac field up to the frequency at which oscillations of the superconducting suspension are limited by inertia. The lifting force was measured as a function of the ac field amplitude and the exposure time. It was shown that the force quickly decreased at the moment the ac field was applied and then continued diminishing, but at a lower rate. A qualitative model was proposed, taking into account two effects of the ac field on the magnetization of the levitating superconductor: a complete destruction of the critical state in some section of the superconductor (to a depth λ ac ) and the initiation of a faster magnetic relaxation in the region where the induction gradient is preserved

  1. Superconducting magnets for toroidal fusion reactors

    International Nuclear Information System (INIS)

    Haubenreich, P.N.

    1980-01-01

    Fusion reactors will soon be employing superconducting magnets to confine plasma in which deuterium and tritium (D-T) are fused to produce usable energy. At present there is one small confinement experiment with superconducting toroidal field (TF) coils: Tokamak 7 (T-7), in the USSR, which operates at 4 T. By 1983, six different 2.5 x 3.5-m D-shaped coils from six manufacturers in four countries will be assembled in a toroidal array in the Large Coil Test Facility (LCTF) at Oak Ridge National Laboratory (ORNL) for testing at fields up to 8 T. Soon afterwards ELMO Bumpy Torus (EBT-P) will begin operation at Oak Ridge with superconducting TF coils. At the same time there will be tokamaks with superconducting TF coils 2 to 3 m in diameter in the USSR and France. Toroidal field strength in these machines will range from 6 to 9 T. NbTi and Nb 3 Sn, bath cooling and forced flow, cryostable and metastable - various designs are being tried in this period when this new application of superconductivity is growing and maturing

  2. Development of partially-stabilized pulsed superconducting magnets

    International Nuclear Information System (INIS)

    Tateishi, Hiroshi; Onishi, Toshitada; Komuro, Kazuo; Koyama, Kenichi

    1987-01-01

    Two types of pulsed superconducting cables and four pulsed superconducting magnets have been developed in order to investigate basic problems in constructing ohmic heating coils of a tokamak-type fusion reactor. We found that a compacted cable is superior in mechanical rigidity and a braided cable is superior in cooling capacity as a conductor of a pulsed magnet. Stored energy and a maximum field of the magnets are 78 kJ and 6 T, 68 kJ and 4 T, 375 kJ and 6 T, and 363 kJ and 3 T, respectively. Some of these magnets quenched in pulsive operations due to excessive ac losses or macroscopic wire motions. Therefore, main conditions for operating pulsed magnets without quenching are (1) to make ac losses low enough to be cooled with liquid helium existing near at the conductor surface by reducing filament diameter to the order of 10 μm and utilizing CuNi as matrix effectively, and (2) to prevent macroscopic wire motions by partial solderfilling of a cable or winding a magnet with strong tension. (author)

  3. Superconducting films of YBaCuO

    International Nuclear Information System (INIS)

    Coelho, A.L.

    1991-01-01

    Thick films of YBa 2 Cu 3 O 7 - x have been prepared on alumina and YSZ (Yttria-stabilized zirconia) substrates by the screen printing technique. Several experimental conditions have been studied, for instance: sintering time, temperature, thickness and atmosphere annealed. The resulting films have been characterized by X-ray diffraction, AC electrical resistance, AC susceptibility and scanning electron microscopy. The surface and cross-section have been observed with an optical microscope. The X-ray diffraction patterns have been compared with a typical pattern and that has indicated the good quality of the samples. AC resistance and its temperature dependence have been measured in the standard four-probe configuration. Films thickness has been estimated in the scanning electron microscope. This technique has been suitable for production of high T c superconducting films being a simple and inexpensive method. (author)

  4. A cooling concept for improved field winding performance in large superconducting ac generators

    International Nuclear Information System (INIS)

    Laskaris, T.E.

    1977-01-01

    An analytical study of a flow circuit for large superconducting generator rotors is presented. The flow circuit provides regulation of the level of liquid in the rotor externally by adjusting the helium supply pressure. It also protects the vapour cooled structural members of the rotor from overcooling during transient periods of operation. Furthermore, it is capable of reducing the winding temperature below 4.2 K thereby enhancing the superconductor's performance. For example, a large generator rotor with NbTi superconducting field winding experiences approximately a 50% increase in its critical current density compared to that at 4.2 K. (author)

  5. DARMSTADT: Superconducting electron accelerator in operation

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    In December, the S-DALINAC superconducting radiofrequency electron accelerator at the Nuclear Physics Institute of Darmstadt's Technische Hochschule was completed. This pioneer continuous-wave (c.w.) machine passed a major milestone several years ago when it accelerated its first low energy electron beam

  6. The use of superconductivity in the USA transportation programme

    International Nuclear Information System (INIS)

    Borcherts, R.H.

    1974-01-01

    US government-sponsored programmes on magnetic suspension, from the Department of Transportation and the National Science Foundation, began in 1971. However, previous work by the Ford Motor Company and the Stanford Research Institute (SRI) had demonstrated the feasibility of magnetic lift-to-drag ratio of 50 to 60 at 134m/s. Current research projects include: SRI's test sled vehicle; a tracked magnetic levitation research vehicle; Magnetic Corporation of America's design study for a superconducting magnet; the linear synchronous motor; and two rotary superconducting machines, the superconducting paddlewheel and the superconducting helix. The next phase of the programme will be a high-speed rocket-propelled test sled to operate on a 1km section of guideway. (author)

  7. Induction motor for superconducting synchronous/asynchronous motor

    International Nuclear Information System (INIS)

    Litz, D.C.; Haller, H.E. III.

    1975-01-01

    An induction motor structure for use on the outside of a superconducting rotor comprising a cylindrical shell of solid and laminated, magnetic iron with squirrel cage windings embedded in the outer circumference of said shell is described. The sections of the shell between the superconducting windings of the rotor are solid magnetic iron. The sections of the shell over the superconducting windings are made of laminations of magnetic iron. These laminations are parallel to the axis of the machine and are divided in halves with the laminations in each half oriented in diagonal opposition so that the intersection of the laminations forms a V. This structure presents a relatively high reluctance to leakage flux from the superconducting windings in the synchronous operating mode, while presenting a low reluctance path to the stator flux during asynchronous operation

  8. Simulation of an HTS Synchronous Superconducting Generator

    DEFF Research Database (Denmark)

    In this work we present a simulation of a synchronous generator with superconducting rotor windings. As many other electrical rotating machines, superconducting generators are exposed to ripple fields that could be produced from a wide variety of sources: short circuit, load change, etc. Unlike...... of heating losses a cumbersome task. Furthermore, the high aspect ratio of the superconducting materials involved adds a penalty in the time required to perform simulations. The chosen strategy for simulation is as follows: A mechanical torque signal together with an electric load is used to drive the finite...... element model of a synchronous generator where the current distribution in the rotor windings is assumed uniform. Then, a second finite element model for the superconducting material is linked to calculate the actual current distribution in the windings of the rotor. Finally, heating losses are computed...

  9. AC susceptibility of thin Pb films in intermediate and mixed state

    Energy Technology Data Exchange (ETDEWEB)

    Janu, Zdenek, E-mail: janu@fzu.cz [Institute of Physics of the AS CR, v.v.i., Na Slovance 2, CZ-182 21 Prague 8 (Czech Republic); Svindrych, Zdenek [Institute of Physics of the AS CR, v.v.i., Na Slovance 2, CZ-182 21 Prague 8 (Czech Republic); Trunecek, Otakar [Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 3, CZ-121 16 Prague 2 (Czech Republic); Kus, Peter; Plecenik, Andrej [Komenius University in Bratislava, Faculty of Mathematics, Physics, and Informatics, Mlynska dolina, 842 48 Bratislava 4 (Slovakia)

    2011-12-15

    Thickness dependent transition in AC susceptibility between intermediate and mixed state in type-I superconducting films. The temperature induced crossover between reversible and irreversible behavior was observed in the thicker film. The temperature dependence of the AC susceptibility in mixed state follows prediction of model based on Bean critical state. The temperature dependence of the harmonics of the complex AC susceptibility in the intermediate state is explained. Thin films of type I superconductors of a thickness comparable or less than a flux penetration length behave like type II superconductors in a mixed state. With decreasing film thickness normal domains carrying a magnetic flux get smaller with smaller number of flux quanta per domain and finally transform into single quantum flux lines, i.e. quantum vortices similar to those found in type II superconductors. We give an evidence of this behavior from the measurements of the nonlinear response of a total magnetic moment to an applied AC magnetic field, directly from the temperature dependence of an AC susceptibility.

  10. Magnetic response of superconducting mesoscopic-size YBCO powder

    Energy Technology Data Exchange (ETDEWEB)

    Deimling, C.V. [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, Sao Carlos, SP (Brazil)], E-mail: cesard@df.ufscar.br; Motta, M.; Lisboa-Filho, P.N. [Laboratorio de Materiais Supercondutores, Departamento de Fisica, Universidade Estadual Paulista, Bauru, SP Brazil (Brazil); Ortiz, W.A. [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, Sao Carlos, SP (Brazil)

    2008-07-15

    In this work it is reported the magnetic behavior of submicron and mesoscopic-size superconducting YBCO powders, prepared by a modified polymeric precursors method. The grain size and microstructure were analyzed using scanning electron microscopy (SEM). Measurements of magnetization and AC-susceptibility as a function of temperature were performed with a quantum design SQUID magnetometer. Our results indicated significant differences on the magnetic propreties, in connection with the calcination temperature and the pressure used to pelletize the samples. This contribution is part of an effort to study vortex dynamics and magnetic properties of submicron and mesoscopic-size superconducting samples.

  11. Alternating current losses of a 10 metre long low loss superconducting cable conductor determined from phase sensitive measurements

    International Nuclear Information System (INIS)

    Krueger Olsen, S.; Kuehle, A.; Traeholt, C.; C Rasmussen, C.; Toennesen, O.; Daeumling, M.; Rasmussen, C.N.; Willen, D.W.A.

    1999-01-01

    The ac loss of a superconducting cable conductor carrying an ac current is small. Therefore the ratio between the inductive (out-of-phase) and the resistive (in-phase) voltages over the conductor is correspondingly high. In vectorial representations this results in phase angles between the current and the voltage over the cable close to 90 degrees. This has the effect that the loss cannot be derived directly using most commercial lock-in amplifiers due to their limited absolute accuracy. However, by using two lock-in amplifiers and an appropriate correction scheme the high relative accuracy of such lock-in amplifiers can be exploited. In this paper we present the results from ac-loss measurements on a low loss 10 metre long high temperature superconducting cable conductor using such a correction scheme. Measurements were carried out with and without a compensation circuit that could reduce the inductive voltage. The 1 μV cm -1 critical current of the conductor was 3240 A at 77 K. At an rms current of 2 kA (50 Hz) the ac loss was derived to be 0.6±0.15 W m -1 . This is, to the best of our knowledge, the lowest value of ac loss of a high temperature superconducting cable conductor reported so far at these high currents. (author)

  12. Comparison of AC losses, magnetic field/current distributions and critical currents of superconducting circular pancake coils and infinitely long stacks using coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Weijia; Campbell, A M; Hong, Z; Ainslie, M D; Coombs, T A, E-mail: wy215@cam.ac.u [Electronic, Power and Energy Conversion Group, Electrical Engineering Division, Engineering Department, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

    2010-08-15

    A model is presented for calculating the AC losses, magnetic field/current density distribution and critical currents of a circular superconducting pancake coil. The assumption is that the magnetic flux lines will lie parallel to the wide faces of tapes in the unpenetrated area of the coil. Instead of using an infinitely long stack to approximate the circular coil, this paper gives an exact circular coil model using elliptic integrals. A new efficient numerical method is introduced to yield more accurate and fast computation. The computation results are in good agreement with the assumptions. For a small value of the coil radius, there is an asymmetry along the coil radius direction. As the coil radius increases, this asymmetry will gradually decrease, and the AC losses and penetration depth will increase, but the critical current will decrease. We find that if the internal radius is equal to the winding thickness, the infinitely long stack approximation overestimates the loss by 10% and even if the internal radius is reduced to zero, the error is still only 60%. The infinitely long stack approximation is therefore adequate for most practical purposes. In addition, the comparison result shows that the infinitely long stack approximation saves computation time significantly.

  13. Transmission line properties of long strings of superconducting magnets

    International Nuclear Information System (INIS)

    Shafer, R.E.

    1980-09-01

    The purpose of this paper is to discuss the electrical characteristics of a long string of superconducting magnets, such as in a superconducting storage ring or accelerator. As the magnets have a shunt capacitance to ground as well as a series inductance, travelling waves can propagate along the string, as in a transmission line. As the string is of finite length, standing waves can also exist. In accelerator quality superconducting magnets, considerable effort has been devoted to minimizing ac losses, the net result being that the magnet string has a high Q precisely at the frequencies which are important for the standing and travelling waves. The magnitude of these effects are estimated, and the solution to be used at Fermilab will be discussed

  14. Electrical characteristics of long strings of SSC superconducting dipoles

    International Nuclear Information System (INIS)

    Shafer, R.E.; Smedley, K.M.

    1992-01-01

    Because long strings of series-connected superconducting magnets have no dc resistance and low ac losses, the string behaves like a shorted transmission line. The string is thus resonant at multiple half-wavelengths unless damped by the inclusion of resistors that couple to the LdI/dt voltage across the magnet inductance. Based on the measured ac characteristics of individual magnets, it is possible to predict the electrical properties of long strings of magnets for a variety of damping resistors. These strings can be simulated using an analytic representation in FORTRAN (using complex-number notation) or a discrete-component equivalent-circuit modelling program (e.g., SPICE). Various electrical parameters, including characteristic impedance, signal velocity, induced power-supply ripple current, attenuation lengths, and driving-point impedances, can be predicted, and the damping resistor value can be optimized. Comparisons will be made to measurements on a long string of superconducting Tevatron magnets, and some predictions will be made for the SSC collider magnet system

  15. Beam simulations with initial bunch noise in superconducting RF proton linacs

    CERN Document Server

    Tückmantel, J

    2010-01-01

    Circular machines are plagued by coupled bunch instabilities (CBI), driven by impedance peaks, where then all cavity higher order modes (HOMs) are possible drivers. Limiting the CBI growth rate is the fundamental reason that all superconducting rf cavities in circular machines are equipped with HOM dampers. The question arises if for similar reasons HOM damping would not be imperative also in high current superconducting rf proton linacs. Therefore we have simulated the longitudinal bunched beam dynamics in such machines, also including charge and position noise on the injected bunches. Simulations were executed for a generic linac with properties close to the planned SPL at CERN, SNS, or Project X at FNAL. It was found that with strong bunch noise and monopole HOMs with high Qext large beam scatter, possibly exceeding the admittance of a receiving machine, cannot be excluded. A transverse simulation shows similar requirements. Therefore including initial bunch noise in any beam dynamic study on superconducti...

  16. High power density superconducting motor for control applications

    International Nuclear Information System (INIS)

    Lopez, J; Granados, X; Lloberas, J; Torres, R; Grau, J; Maynou, R; Bosch, R

    2008-01-01

    A high dynamics superconducting low power motor for control applications has been considered for design. The rotor is cylindrical with machined bulks that generate the field by trapping flux in a four poles configuration. The toothless iron armature is wound by copper, acting iron only as magnetic screen. Details of the magnetic assembling, cryogenics and electrical supply conditioning will be reported. Improvements due to the use of a superconducting set are compared with performances of equivalent conventional motors

  17. Self-field AC losses and critical currents in multi-tube Ag-Bi-2223 conductors

    Energy Technology Data Exchange (ETDEWEB)

    Ciszek, M; Ashworth, S P; Campbell, A M [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); James, M P; Glowacki, B A [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Garre, R; Conti, S [Centro Ricerche Europa Metalli, Fornaci di Barga, LU (Italy)

    1996-05-01

    The purpose of this work was to investigate the influence of different technological treatments of silver sheathed Bi-2223 tapes on the critical current density and the AC transport losses. The tapes were produced using the 'tube-in-tube' technique, by including a silver rod in the centre of the superconducting powder during packing of the silver tube. The aim of the process is to increase the silver to superconductor surface area and thus also the alignment at the centre of the conductor ceramic core. AC transport losses were measured by means of an electrical method using sinusoidally varying currents in the frequency range 30-180 Hz. In this range the power losses are hysteretic. The measured variation in losses from those predicted by a critical state model is attributed to the complex geometry of superconducting regions existing in these tapes. (author)

  18. MD 349: Impedance Localization with AC-dipole

    CERN Document Server

    Biancacci, Nicolo; Metral, Elias; Salvant, Benoit; Papotti, Giulia; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to measure the distribution of the transverse impedance of the LHC by observing the phase advance variation with intensity between the machine BPMs. Four injected bunches with different intensities are excited with an AC dipole and the turn by turn data is acquired from the BPM system. Through post-processing analysis the phase variation along the machine is depicted and, from this information, first conclusions of the impedance distribution can be drawn.

  19. HOM Dampers or not in Superconducting RF Proton Linacs

    CERN Document Server

    Tückmantel, Joachim

    2009-01-01

    Circular machines are plagued by Coupled Bunch Instabilities, driven by impedance peaks, irrespectively of their frequency relation to machine lines; hence all cavity Higher Order Modes are possible drivers. This is the fundamental reason that all superconducting RF cavities in circular machines are equipped with HOM dampers. This raises the question if HOM damping would not be imperative also in high current proton linacs where a mechanism akin to CBI might exist. To clarify this question we have simulated the longitudinal bunched beam dynamics in linacs, allowing bunch-to-bunch variations in time-of-arrival. Simulations were executed for a generic proton linac with properties close to SNS or the planned SPL at CERN. It was found that for monopole HOMs with high Qext large beam scatter or even beam loss cannot be excluded. Therefore omitting HOM dampers on superconducting RF cavities in high current proton linacs, even pulsed ones, is a very risky decision.

  20. HOM Dampers or not in SUPERCONDUCTING RF Proton Linacs

    CERN Document Server

    Tückmantel, Joachim

    2009-01-01

    Circular machines are plagued by Coupled Bunch Instabilities, driven by impedance peaks, irrespectively of their frequency relation to machine lines; hence all cavity Higher Order Modes are possible drivers. This is the fundamental reason that all superconducting RF cavities in circular machines are equipped with HOM dampers. This raises the question if HOM damping would not be imperative also in high current proton linacs where a mechanism akin to CBI might exist. To clarify this question we have simulated the longitudinal bunched beam dynamics in linacs, allowing bunch-to-bunch variations in time-of-arrival. Simulations were executed for a generic proton linac with properties close to SNS or the planned SPL at CERN. It was found that for monopole HOMs with high Qext large beam scatter or even beam loss cannot be excluded. Therefore omitting HOM dampers on superconducting RF cavities in high current proton linacs, even pulsed ones, is a very risky decision.

  1. Ac-driven vortex-antivortex dynamics in nanostructured superconductor-ferromagnetic hybrids

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Clessio L.S., E-mail: clsl@df.ufpe.br [Nucleo de Tecnologia, Centro Academico do Agreste, Universidade Federal de Pernambuco, 55002-970 Caruaru-PE (Brazil); Souza Silva, Clecio C. de; Aguiar, J. Albino [Departamento de Fisica, Universidade Federal de Pernambuco, 50670-901 Recife-PE (Brazil)

    2012-09-15

    The dynamics of ac-driven vortices and antivortices in a superconducting film interacting with an array of magnetic dipoles on top is investigated via hybrid molecular dynamics-Monte Carlo simulations. The dipole array considered in this study is capable to stabilize in equilibrium vortex-antivortex pairs. The appearance of a net electric field out of the ac excitation demonstrates that this system behaves as a voltage rectifier. Because of the asymmetric nature of the effective pinning potential generated by the dipole array, the ac-driven vortices and antivortices are ratcheted in opposite directions, thereby contributing additively to the observed net voltage. In addition, for high frequency values, the dc electric field-ac amplitude curves present a series of steps. A careful analysis of the time series of the electric field and number of vortex-antivortex (v-av) pairs reveals that these steps are related to mode-locking between the drive frequency and the number of v-av creation-annihilation events.

  2. Superconducting generators for wind turbines: design considerations

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Abrahamsen, Asger Bech; Træholt, Chresten

    2010-01-01

    The harmonic content of high temperature superconductors (HTS) field winding in air-core high temperature superconducting synchronous machine (HTS SM) has been addressed in order to investigate tendency of HTS SM towards mechanical oscillation and additional loss caused by higher flux harmonic...

  3. Multi-phase alternative current machine winding design | Khan ...

    African Journals Online (AJOL)

    ... single-phase to 18-phase excitation. Experimental results of a five-phase induction machine supplied from a static five-phase supply are provided to support the proposed design. Keywords: AC machine, Multi-phase machine, Stator winding, Five-phase. International Journal of Engineering, Science and Technology, Vol.

  4. Beam tests and operation of superconducting cavities

    International Nuclear Information System (INIS)

    Akai, Kazunori

    1990-01-01

    Beam tests and operation of superconducting cavities conducted since the third workshop on RF superconductivity (Argonne, Sep. 1987) are reported in this paper. The paper is concerned particularly with electron machines. Storage and acceleration of the beam are discussed, focusing on the CERN test in SPS, the DESY test in PETRA, the superconducting injector at Darmstadt, and the KEK beam tests in T-AR. Then, long-term performance of the cavity in the ring is discussed focusing on Eacc (max) and O-value, environmental conditions, and operational experience in T-MR. RF controllability is addressed, centering on the Robinson stability, cavity tuning loop, quench detection and interlocks, recovery procedure, field calibration, and phase adjustment. Higher order modes are also discussed. Superconducting cavities have been operated successfully in accelerators. It has been confirmed that the superconducting cavities can be used stably for experimental use. For more than 5000 hours the cavities have indicated no essential degradation of the cavity performance. The study of long-term performance should be continued in longer range of period. (N.K.)

  5. Neutron irradiation therapy machine

    International Nuclear Information System (INIS)

    1980-01-01

    Conventional neutron irradiation therapy machines, based on the use of cyclotrons for producing neutron beams, use a superconducting magnet for the cyclotron's magnetic field. This necessitates complex liquid He equipment and presents problems in general hospital use. If conventional magnets are used, the weight of the magnet poles considerably complicates the design of the rotating gantry. Such a therapy machine, gantry and target facilities are described in detail. The use of protons and deuterons to produce the neutron beams is compared and contrasted. (U.K.)

  6. Superconducting Material - A study on the near field of a superconducting antenna

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soon Chil; Lee, Seung Chul; Doe, Joong Hoe; Hoe, Mi Ra [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1996-07-01

    The pulse spectroscopy in combination with piezoelectric resonance makes an ideal non-disturbing tool for the measurement of electric field near an antenna. This new field sensing technique was used to investigate the field of a ring antenna the near field of which is widely used such as the plasma generation and NMR. The superconducting wire also have the dominant capacitive AC field in near regions, meaning that the net charge on the ring surface is not due to the ohm`s law as in DC. 23 refs., 8 figs. (author)

  7. Magnetic ordering of Gd/sub x/Er/sub 1-x/Rh4B4 near the superconducting region

    International Nuclear Information System (INIS)

    Kohn, S.; Wang, R.H.; Smith, J.L.; Huang, C.Y.

    1979-01-01

    Gd/sub x/Er/sub 1-x/Rh 4 B 4 exhibits superconductivity at some critical temperature T/sub c/ followed by the onset of long-range ferromagnetic ordering at a lower temperature and a loss of superconductivity for x 2 Oe), the extrema in chi (T) and R(T) are depressed and smeared considerably with a corresponding shift in the temperature at which the extrema occur. (2) The sample is not superconducting down to 0.6 K. (3) In the presence of a dc magnetic field, a second ac chi peak appears at a slightly higher temperature. (4) The field dependence of the ac susceptibility resembles that of a spin glass. Details of the field dependence of these observations and the nature of these phenomena will be presented

  8. First-Principles Study of Superconductivity in Ultra- thin Pb Films

    Science.gov (United States)

    Noffsinger, Jesse; Cohen, Marvin L.

    2010-03-01

    Recently, superconductivity in ultrathin layered Pb has been confirmed in samples with as few as two atomic layers [S. Qin, J. Kim, Q. Niu, and C.-K. Shih, Science 2009]. Interestingly, the prototypical strong-coupling superconductor exhibits different Tc's for differing surface reconstructions in samples with only two monolayers. Additionally, Tc is seen to oscillate as the number of atomic layers is increased. Using first principles techniques based on Wannier functions, we analyze the electronic structure, lattice dynamics and electron-phonon coupling for varying thicknesses and surface reconstructions of layered Pb. We discuss results as they relate to superconductivity in the bulk, for which accurate calculations of superconducting properties can be compared to experiment [W. L. McMillan and J.M. Rowell, PRL 1965]. This work was supported by National Science Foundation Grant No. DMR07-05941, the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Computational resources have been provided by the Lawrencium computational cluster resource provided by the IT Division at the Lawrence Berkeley National Laboratory (Supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231)

  9. Critical current measurement in superconducting rings using an automatic inductive technique

    International Nuclear Information System (INIS)

    Gonzalez-Jorge, H.; Linares, B.; Quelle, I.; Carballo, E.; Romani, L.; Domarco, G.

    2007-01-01

    A measurement technique was developed to identify the critical current of superconducting rings. It is based on the detection of the voltage on a secondary coil when the current induced in the superconductor by a primary one go beyond to the critical value. The technique uses a DC power supply to control the AC current circulating by the primary circuit. Such circuit mainly consists on an AC power supply which gives a constant AC voltage, a primary inducting coil and a control coil with iron core. The AC current circulating by this circuit is modified with the change in the impedance of the control coil due to the fact of the DC current supplied by the power supply in parallel with it

  10. Optimization of superconducting bending magnets for a 1.0 to 1.5 GeV compact light source

    International Nuclear Information System (INIS)

    Green, M.A.; Garren, A.A.

    1995-06-01

    Compact light sources are being proposed for protein crystallography, medical imaging, nano-machining and other areas of study that require intense sources of x rays at energies up to 35 keV. In order for a synchrotron light source to be attractive, its capital cost must, be kept low. The proposed compact light source has superconducting bending elements to bend the stored beam and produce the x rays. Additional focusing for the machine is provided by conventional quadrupoles. An important part of the cost optimization of a compact light source is the cost of the bending magnets. In the case of a machine with superconducting bending elements, the bending magnet system can represent close to half of the storage ring cost. The compact light source storage rings studied here have a range of stored electron energies from 1.0 to 1.5 GeV. For a number of reasons, it is desirable to keep the storage ring circumference below 30 meters. Cost optimization parameters include: (1) the number of superconducting bending elements in the ring, and (2) the central induction of the dipole. A machine design that features two superconducting dipoles in a single cryostat vacuum vessel is also discussed

  11. Linac boosters for electrostatic machines

    International Nuclear Information System (INIS)

    Ben-Zvi, I.; Brookhaven National Lab., Upton, NY

    1990-01-01

    A survey of linacs which are used as boosters to electrostatic accelerators is presented. Machines both operating and under construction, copper and superconducting, are reviewed. The review includes data on the accelerating structures, performance, rf and control, beam optics, budget, vacuum and cryogenics. (orig.)

  12. LHC Report: superconducting circuit powering tests

    CERN Multimedia

    Mirko Pojer

    2015-01-01

    After the long maintenance and consolidation campaign carried out during LS1, the machine is getting ready to start operation with beam at 6.5 TeV… the physics community can’t wait! Prior to this, all hardware and software systems have to be tested to assess their correct and safe operation.   Most of the cold circuits (those with high current/stored energy) possess a sophisticated magnet protection system that is crucial to detect a transition of the coil from the superconducting to the normal state (a quench) and safely extract the energy stored in the circuits (about 1 GJ per dipole circuit at nominal current). LHC operation relies on 1232 superconducting dipoles with a field of up to 8.33 T operating in superfluid helium at 1.9 K, along with more than 500 superconducting quadrupoles operating at 4.2 or 1.9 K. Besides, many other superconducting and normal resistive magnets are used to guarantee the possibility of correcting all beam parameters, for a total of mo...

  13. Vortex pinning vs superconducting wire network: origin of periodic oscillations induced by applied magnetic fields in superconducting films with arrays of nanomagnets

    International Nuclear Information System (INIS)

    Gomez, A; Del Valle, J; Gonzalez, E M; Vicent, J L; Chiliotte, C E; Carreira, S J; Bekeris, V; Prieto, J L; Schuller, Ivan K

    2014-01-01

    Hybrid magnetic arrays embedded in superconducting films are ideal systems to study the competition between different physical (such as the coherence length) and structural length scales such as are available in artificially produced structures. This interplay leads to oscillation in many magnetically dependent superconducting properties such as the critical currents, resistivity and magnetization. These effects are generally analyzed using two distinct models based on vortex pinning or wire network. In this work, we show that for magnetic dot arrays, as opposed to antidot (i.e. holes) arrays, vortex pinning is the main mechanism for field induced oscillations in resistance R(H), critical current I c (H), magnetization M(H) and ac-susceptibility χ ac (H) in a broad temperature range. Due to the coherence length divergence at T c , a crossover to wire network behaviour is experimentally found. While pinning occurs in a wide temperature range up to T c , wire network behaviour is only present in a very narrow temperature window close to T c . In this temperature interval, contributions from both mechanisms are operational but can be experimentally distinguished. (papers)

  14. Superconducting-electromagnetic hybrid bearing using YBCO bulk blocks for passive axial levitation

    Science.gov (United States)

    Nicolsky, R.; de Andrade, R., Jr.; Ripper, A.; David, D. F. B.; Santisteban, J. A.; Stephan, R. M.; Gawalek, W.; Habisreuther, T.; Strasser, T.

    2000-06-01

    A superconducting/electromagnetic hybrid bearing has been designed using active radial electromagnetic positioning and a superconducting passive axial levitator. This bearing has been tested for an induction machine with a vertical shaft. The prototype was conceived as a four-pole, two-phase induction machine using specially designed stator windings for delivering torque and radial positioning simultaneously. The radial bearing uses four eddy-current sensors, displaced 90° from each other, for measuring the shaft position and a PID control system for feeding back the currents. The stator windings have been adapted from the ones of a standard induction motor. The superconducting axial bearing has been assembled with commercial NdFeB permanent magnets and a set of seven top-seeded-melt-textured YBCO large-grain cylindrical blocks. The bearing set-up was previously simulated by a finite element method for different permanent magnet-superconductor block configurations. The stiffness of the superconducting axial bearing has been investigated by measuring by a dynamic method the vertical and transversal elastic constants for different field cooling processes. The resulting elastic constants show a linear dependence on the air gap, i.e. the clearance between the permanent magnet assembly and the set of superconducting large-grain blocks, which is dependent on cooling distance.

  15. High temperature superconductive flux gate magnetometer

    International Nuclear Information System (INIS)

    Gershenson, M.

    1991-01-01

    This paper proposes a different type of HTS superconducting magnetometer based on the non-linear magnetic behavior of bulk HTS materials. The device design is based on the generation of second harmonics which arise as a result of non-linear magnetization observed in Type-II superconductors. Even harmonics are generated from the non-linear interaction of an ac excitation signal with an external DC magnetic field which acts as a bias signal

  16. Prediction of Chevrel superconducting phases

    International Nuclear Information System (INIS)

    Savitskij, E.M.; Kiseleva, N.N.

    1978-01-01

    Made is an attempt of predicting the possibility of formation of compounds of Mo 3 Se 4 type structure having critical temperatures of transition into superconducting state more than 4.2 K. Cybernetic method of teaching an electronic computer to form notions is used for prediction. Prediction system constructs logic dependence of forming Chevrel superconducting phase of the Asub(x)Bsub(6)Ssub(8) composition (A being an element of the periodic system; B=Cr, Mo, W, Re) and Asub(x)Bsub(6)Ssub(8) compounds having a critical temperature of more than 4.2 K on the properties of A and B elements. A conclusion is made that W, Re, Cr do not form Chevrel phases of the Asub(x)Bsub(6)Ssub(8) composition as B component. Be, Hg, Ra, B, Ac are the reserve for obtaining Asub(x)Mosub(6)Ssub(8) phases. Agsub(x)Mosub(6)Ssub(8) compound may have a high critical temperature. The ways of a critical temperature increase for Chevrel phases are connected with the search of optimal technological conditions for already known superconducting compounds and also with introduction of impurities fixing a distance between sulfur cubes

  17. The achievements of the Z-machine; Les exploits de la Z-machine

    Energy Technology Data Exchange (ETDEWEB)

    Larousserie, D

    2008-03-15

    The ZR-machine that represents the latest generation of Z-pinch machines has recently begun preliminary testing before its full commissioning in Albuquerque (Usa). During its test the machine has well operated with electrical currents whose intensities of 26 million Ampere are already 2 times as high as the intensity of the operating current of the previous Z-machine. In 2006 the Z-machine reached temperatures of 2 billions Kelvin while 100 million Kelvin would be sufficient to ignite thermonuclear fusion. In fact the concept of Z-pinch machines was imagined in the fifties but the technological breakthrough that has allowed this recent success and the reborn of Z-machine, was the replacement of gas by an array of metal wires through which the electrical current flows and vaporizes it creating an imploding plasma. It is not well understood why Z-pinch machines generate far more radiation than theoretically expected. (A.C.)

  18. Anisotropic superconductivity in {beta}-(BDA-TTP){sub 2}SbF{sub 6}: STM spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, K. [Department of Physics, Hokkaido University, Sapporo 060-0810 (Japan)], E-mail: knmr@phys.sci.hokudai.ac.jp; Muraoka, R.; Matsunaga, N. [Department of Physics, Hokkaido University, Sapporo 060-0810 (Japan); Ichimura, K. [Division of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Yamada, J. [Division of Material Science, University of Hyogo, Hyogo 678-1297 (Japan)

    2009-03-01

    We have investigated the gap symmetry in the superconducting phase of {beta}-(BDA-TTP){sub 2}SbF{sub 6} with use of the scanning tunneling microscope (STM). The tunneling spectra obtained on the conducting surface show a clear superconducting gap structure. Its functional form is of V-shaped similarly to {kappa}-(BEDT-TTF){sub 2}X and suggests the anisotropic superconducting gap with line nodes. For lateral surfaces the shape of tunneling spectra varies from the U-shape with relatively large gap to the V-shape with small gap depending on the tunneling direction alternately twice between directional angle 0 and {pi}. From the analysis of conductance curve taking the k dependence of the tunneling probability into account, it is found that the gap has maximum near the a* and c* axes and the nodes appear along near a*+c* and the a-c* directions. These indicate that the d{sub x{sup 2}-y{sup 2}} like superconducting pair is formed in this system as the case of {kappa}-(BEDT-TTF){sub 2}X. This node direction is consistent with the theoretical prediction based on the spin fluctuation mechanism. However, the zero-bias conductance peak has not been observed yet.

  19. General Atomic's superconducting toroidal field coil concept

    International Nuclear Information System (INIS)

    Alcorn, J.; Purcell, J.

    1978-01-01

    General Atomic's concept for a superconducting toroidal field coil is presented. The concept is generic for large tokamak devices, while a specific design is indicated for a 3.8 meter (major radius) ignition/burn machine. The concept utilizes bath cooled NbTi conductor to generate a peak field of 10 tesla at 4.2 K. The design is simple and straightforward, requires a minimum of developmental effort, and draws extensively upon the perspective of past experience in the design and construction of large superconducting magnets for high energy physics. Thus, the primary emphasis is upon economy, reliability, and expeditious construction scheduling. (author)

  20. On the relevance of the ac magnetic susceptibility on the study of superconductors

    International Nuclear Information System (INIS)

    Khoder, A.F.; Couach, M.; Barbara, B.

    1988-01-01

    It is shown that the ac susceptibility method allows to study in details the bulk superconductivity of as well homogeneous and inhomogeneous materials, such as high-T c superconductors. Shielding and Meissner effects at T c can be distinguished by a careful analysis of x' and x'' components of the susceptibility

  1. Design and Performance Improvement of AC Machines Sharing a Common Stator

    Science.gov (United States)

    Guo, Lusu

    With the increasing demand on electric motors in various industrial applications, especially electric powered vehicles (electric cars, more electric aircrafts and future electric ships and submarines), both synchronous reluctance machines (SynRMs) and interior permanent magnet (IPM) machines are recognized as good candidates for high performance variable speed applications. Developing a single stator design which can be used for both SynRM and IPM motors is a good way to reduce manufacturing and maintenance cost. SynRM can be used as a low cost solution for many electric driving applications and IPM machines can be used in power density crucial circumstances or work as generators to meet the increasing demand for electrical power on board. In this research, SynRM and IPM machines are designed sharing a common stator structure. The prototype motors are designed with the aid of finite element analysis (FEA). Machine performances with different stator slot and rotor pole numbers are compared by FEA. An 18-slot, 4-pole structure is selected based on the comparison for this prototype design. Sometimes, torque pulsation is the major drawback of permanent magnet synchronous machines. There are several sources of torque pulsations, such as back-EMF distortion, inductance variation and cogging torque due to presence of permanent magnets. To reduce torque pulsations in permanent magnet machines, all the efforts can be classified into two categories: one is from the design stage, the structure of permanent magnet machines can be optimized with the aid of finite element analysis. The other category of reducing torque pulsation is after the permanent magnet machine has been manufactured or the machine structure cannot be changed because of other reasons. The currents fed into the permanent magnet machine can be controlled to follow a certain profile which will make the machine generate a smoother torque waveform. Torque pulsation reduction methods in both categories will be

  2. Development of superconducting pulsed poloidal coil in JAERI

    International Nuclear Information System (INIS)

    Shimamoto, S.; Okuno, K.; Ando, T.; Tsuji, H.

    1990-01-01

    In the Japan Atomic Energy Research Institute, (JAERI), development work on pulsed superconductors and coils started in 1979, aiming at the demonstration of the applicability of superconducting technologies to pulsed poloidal coils in a fusion reactor. Initially our effort was concentrated mainly on the development of pool-cooled large-current pulsed conductors. Over the past ten years, superconducting technology has made great progress and the forced-flow cooled coil has assumed great importance in the development work. Now the Demo Poloidal Coil Project is in progress in JAERI, and three large forced-flow cooled coils have so far been fabricated and tested. Many improvements have been achieved in ac-loss performance and mechanical characteristics. (author)

  3. Current distribution and ac susceptibility response of a thin superconducting disc in an axial field: a theoretical approach

    Science.gov (United States)

    Aruna, S. A.; Zhang, P.; Lin, F. Y.; Ding, S. Y.; Yao, X. X.

    2000-04-01

    Within the framework of the thermally activated process of the flux line or flux line bundles, and by time integration of the 1D equation of motion of the circulating current density icons/Journals/Common/vecJ" ALT="vecJ" ALIGN="TOP"/> (icons/Journals/Common/rho" ALT="rho" ALIGN="TOP"/> ,t ), which is suitable for thin superconducting films (R >>d ,icons/Journals/Common/le" ALT="le" ALIGN="TOP"/> icons/Journals/Common/lambda" ALT="lambda" ALIGN="TOP"/> ), we present numerical calculations of the current profiles, magnetization hysteresis loops and ac susceptibility icons/Journals/Common/chi" ALT="chi" ALIGN="TOP"/> n = icons/Journals/Common/chi" ALT="chi" ALIGN="TOP"/> ´n +iicons/Journals/Common/chi" ALT="chi" ALIGN="TOP"/> ´´n for n = 1, 3 and 5 of a thin disc immersed in an axial time-dependent external magnetic field Ba (t ) = Bdc +Bac cos(2icons/Journals/Common/pi" ALT="pi" ALIGN="TOP"/> icons/Journals/Common/nu" ALT="nu" ALIGN="TOP"/> t ). Our calculated results are compared with those of the critical state model (CSM) and found to prove the approximate validity of the CSM below the irreversibility field. The differences between our computed results and those of the CSM are also discussed.

  4. Superconductivity in a copper(II)-based coordination polymer with perfect kagome structure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xing; Liu, Liyao; Xu, Wei; Zhu, Daoben [Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing (China); University of Chinese Academy of Sciences, Beijing (China); Zhang, Shuai [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing (China); Yu, Lei [Department of Chemistry, University of Kentucky, Lexington, KY (United States); Chen, Genfu [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing (China); University of Chinese Academy of Sciences, Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)

    2018-01-02

    A highly crystalline copper(II) benzenehexathiolate coordination polymer (Cu-BHT) has been prepared. The two-dimensional kagome structure has been confirmed by powder X-ray diffraction, high-resolution transmission electron microscopy, and high-resolution scanning transmission electron microscopy. The as-prepared sample exhibits bulk superconductivity at about 0.25 K, which is confirmed by the zero resistivity, AC magnetic susceptibility, and specific heat measurements. Another diamagnetic transition at about 3 K suggests that there is a second superconducting phase that may be associated with a single layer or few layers of Cu-BHT. It is the first time that superconductivity has been observed in a coordination polymer. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Optimization of a Superconducting Magnetic Energy Storage Device via a CPU-Efficient Semi-Analytical Simulation

    OpenAIRE

    Dimitrov, I K; Zhang, X; Solovyov, V F; Chubar, O; Li, Qiang

    2014-01-01

    Recent advances in second generation (YBCO) high temperature superconducting wire could potentially enable the design of super high performance energy storage devices that combine the high energy density of chemical storage with the high power of superconducting magnetic storage. However, the high aspect ratio and considerable filament size of these wires requires the concomitant development of dedicated optimization methods that account for both the critical current density and ac losses in ...

  6. Warm measurements of CBA superconducting magnets

    International Nuclear Information System (INIS)

    Engelmann, R.; Herrera, J.; Kahn, S.; Kirk, H.; Willen, E.; Yamin, P.

    1983-01-01

    We present results on magnetic field measurements of CBA dipole magnets in the warm (normal conductor) and cryogenic (superconducting) states. We apply two methods for the warm measurements, a dc and ac method. We find a good correlation between warm and cryogenic measurements which lends itself to a reliable diagnosis of magnet field errors using warm measurements early in the magnet assembly process. We further find good agreement between the two warm measurement methods, both done at low currents

  7. Study of structure of HTS coated conductor with ferromagnetic substrate having low AC transport current loss using FEM

    International Nuclear Information System (INIS)

    Miyagi, D.; Amadutsumi, Y.; Takahashi, N.; Tsukamoto, O.

    2007-01-01

    AC transport current losses of coated conductors with ferromagnetic substrates are higher than the loss calculated by the Norris equation. In order to reduce the AC transport current loss we propose in this paper a structure of the coated conductor that has wider substrate than the SC (Superconducting) layer. The current distribution and AC loss of the proposed model are analyzed by means of FEM. The AC transport current loss is reduced due to the change of current density distribution near the edge of SC layer, consequent to the high value of magnetic permeability of the ferromagnetic substrate, that is wider than the SC layer

  8. Simulation of an HTS Synchronous Superconducting Generator

    DEFF Research Database (Denmark)

    Rodriguez Zermeno, Victor Manuel; Abrahamsen, Asger Bech; Mijatovic, Nenad

    2012-01-01

    In this work we present a simulation of a synchronous generator with superconducting rotor windings. As many other,electrical rotating machines, superconducting generators are exposed to ripple fields that could be produced from a wide variety of sources: short circuit, load change, mechanical...... with an electric load is used to drive the finite element model of a synchronous generator where the current distribution in the rotor windings is assumed uniform. Then, a second finite element model for the superconducting material is linked to calculate the actual current distribution in the windings...... of the rotor. Finally, heating losses are computed as a response to the electric load. The model is used to evaluate the transient response of the generator. © 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of the Guest Editors....

  9. Detection of magnetic nanoparticles with a large scale AC superconducting susceptometer

    Science.gov (United States)

    Hincapie Ladino, E. A.; Zufelato, N.; Bakuzis, A. F.; Oliveira Carneiro, A. A.; Covas, D. T.; Baffa, O.

    2017-08-01

    Magnetic nanoparticles (MNPs) are being used in several applications in medicine such as hyperthermia, magnetic particle imaging, in vitro and in vivo bioassay, and still there are many other possibilities for use of these particles to come as research progress in this field. One crucial step of its use is the detection of these particles when present in a certain tissue. For in vitro bioassay, the sample can be harvested and placed inside the detector in optimal conditions to favor sensitivity. However, for in vivo human measurements the system must be noninvasive and conform to the anatomic restrictions requiring sensitive detectors and dedicated setups. In this study, we detect nanoparticles with an AC biosusceptometer having an excitation homogeneous magnetic field with 145 μT, provided by a set of rectangular large Rubens coils driven at 10 Hz. The magnetization induced in the sample was detected by a second-order axial gradiometer (20 mm in diameter and 40 mm of baseline) coupled to an RF Superconducting Quantum Interference Device (SQUID) model 330X (BTi). The MNPs used were manganese ferrite-based surface-coated with citric acid ({{M}}{{n}}{{F}}{{{e}}}2{{{O}}}4-{{C}}{{i}}{{t}}{{r}}{{a}}{{t}}{{e}}), dissolved in water at various concentrations. The colloid is stable at physiological conditions. X-ray diffraction confirmed the spinel structure and using Scherrer’s relation revealed a particle size of 17.3 nm. The magnetization curve showed a typical superparamagnetic behavior with a specific saturation magnetization of 51.2 emu g-1. The stock solution of nanoparticles had a concentration of 23.17 mg ml-1, corresponding to 1.7 × 1015 NPs ml-1. Measurements were made in a volume of 30 ml with 20 × 103-100 × 103 dilutions of the stock solution of nanoparticles and performed at distances of 1.1, 1.5 and 2.5 cm from the top of the sample vial to the closest coil of the gradiometer. The limits of detection were 8.1 × 109 NP ml-1, 9.5 × 109 NP ml-1 and 11

  10. Design of MgB2 Superconducting coils for the Ignitor Experiment*

    Science.gov (United States)

    Grasso, G.; Penco, R.; Berta, S.; Coppi, B.; Giunchi, G.

    2009-11-01

    A feasibility study for the adoption of MgB2 superconducting cables for the largest (about 5 m in diameter) of the poloidal field coils of the Ignitor machine is being carried out. This initiative was prompted by the progress made in the fabrication of MgB2 long cables, and related superconducting magnets of relatively large dimensions. These magnets will be cryocooled at the operating temperature of 10-15 K that is compatible with the He-gas cryogenic cooling system of Ignitor as well as with the projected superconducting current density of the MgB2 material, at the magnetic field values (˜4-5 T) in which these coils are designed to operate. The optimal cable configuration has been identified that can provide an efficient cooling of the MgB2 conductors over times compatible with the machine duty cycles. MgB2 superconductors hold the promise of becoming suitable for high field magnets by appropriate doping of the material and of replacing gradually the normal conducting coils adopted, by necessity, in high field experiments. Therefore, an appropriate R&D program on the development of improved MgB2 material and related superconducting cabling options has been undertaken, involving different institutions.

  11. Lattice parameters guide superconductivity in iron-arsenides

    Science.gov (United States)

    Konzen, Lance M. N.; Sefat, Athena S.

    2017-03-01

    The discovery of superconducting materials has led to their use in technological marvels such as magnetic-field sensors in MRI machines, powerful research magnets, short transmission cables, and high-speed trains. Despite such applications, the uses of superconductors are not widespread because they function much below room-temperature, hence the costly cooling. Since the discovery of Cu- and Fe-based high-temperature superconductors (HTS), much intense effort has tried to explain and understand the superconducting phenomenon. While no exact explanations are given, several trends are reported in relation to the materials basis in magnetism and spin excitations. In fact, most HTS have antiferromagnetic undoped ‘parent’ materials that undergo a superconducting transition upon small chemical substitutions in them. As it is currently unclear which ‘dopants’ can favor superconductivity, this manuscript investigates crystal structure changes upon chemical substitutions, to find clues in lattice parameters for the superconducting occurrence. We review the chemical substitution effects on the crystal lattice of iron-arsenide-based crystals (2008 to present). We note that (a) HTS compounds have nearly tetragonal structures with a-lattice parameter close to 4 Å, and (b) superconductivity can depend strongly on the c-lattice parameter changes with chemical substitution. For example, a decrease in c-lattice parameter is required to induce ‘in-plane’ superconductivity. The review of lattice parameter trends in iron-arsenides presented here should guide synthesis of new materials and provoke theoretical input, giving clues for HTS.

  12. Measurement of AC losses in a racetrack superconducting coil made from YBCO coated conductor

    DEFF Research Database (Denmark)

    Seiler, Eugen; Abrahamsen, Asger Bech; Kovac, Jan

    2012-01-01

    to reinforce it. The AC loss is measured versus the transport current Ia with the coil immersed in liquid nitrogen. Measurements at frequencies 21 Hz, 36 Hz and 72 Hz are compared. The AC losses follow I2 a dependence at low current amplitudes and I3 a at high amplitudes. After cutting the inner steel frame...

  13. Argonne National Laboratory superconducting pulsed coil program

    International Nuclear Information System (INIS)

    Wang, S.T.; Kim, S.H.

    1979-01-01

    The main objectives are to develop high current (approx. 100 kA) cryostable cable configurations with reasonably low ac losses, to build a demonstration pulsed coil, and to develop a rather inexpensive large fiberglass reinforced helium cryostat. A 1.5-MJ cryostable pulsed superconducting coil has been developed and constructed at ANL. The coil has a peak field of 4.5 T at an operating current of 11.0 kA. A large inexpensive plastic cryostat has been developed for testing the pulsed coil. The coil has been pulsed with a maximum dB/dt of 11 T/s. The coil was pulsed more than 4000 cycles. Detailed results of the ac loss measurements and the current sharing of the cryostability will be described

  14. AC losses in superconductors: a multi-scale approach for the design of high current cables

    International Nuclear Information System (INIS)

    Escamez, Guillaume

    2016-01-01

    The work reported in this PhD deals with AC losses in superconducting material for large scale applications such as cables or magnets. Numerical models involving FEM or integral methods have been developed to solve the time transient electromagnetic distributions of field and current densities with the peculiarity of the superconducting constitutive E-J equation. Two main conductors have been investigated. First, REBCO superconductors for applications operating at 77 K are studied and a new architecture of conductor (round wires) for 3 kA cables. Secondly, for very high current cables, 3-D simulations on MgB_2 wires are built and solved using FEM modeling. The following chapter introduced new development used for the calculation of AC losses in DC cables with ripples. The thesis ends with the use of the developed numerical model on a practical example in the european BEST-PATHS project: a 10 kA MgB_2 demonstrator [fr

  15. Ac susceptibility studies on Bi-Sr-Ca-Cu-O system

    International Nuclear Information System (INIS)

    Chakravarti, Arani; Mukherjee, C.D.; Ranganathan, R.; Chatterjee, N.; Raychaudhuri, A.K.

    1991-01-01

    We report the low a.c. susceptibility data χ'(T,Hsub(rms)), χsup(double inverted commas)(T,Hsub(rms)) for the newly prepared superconducting system Bi x Sr 4 Ca 2 Cu 4 O y (x=0.5, 1.0 and 1.5) containing Bi at concentrations lower than that in the conventional Bi-based system. The experimental results are discussed in the light of existing theories. (author). 10 refs., 3 figs

  16. Experimental setup for precise measurement of losses in high-temperature superconducting transformer

    Czech Academy of Sciences Publication Activity Database

    Janů, Zdeněk; Wild, J.; Řepa, P.; Jelínek, Z.; Žížek, F.; Peksa, L.; Soukup, František; Tichý, Rudolf

    2006-01-01

    Roč. 46, - (2006), s. 759-761 ISSN 0011-2275 R&D Projects: GA ČR GA102/05/0942 Institutional research plan: CEZ:AV0Z10100520 Keywords : superconducting transformer * AC losses * calorimeters Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.927, year: 2006

  17. Superconducting endcap toroid design report

    Energy Technology Data Exchange (ETDEWEB)

    Walters, C.R.; Baynham, D.E.; Holtom, E.; Coombs, R.C.

    1992-10-01

    The Atlas Experiment proposed for the LHC machine will use toroidal magnet systems to achieve high muon momentum resolutions. One of the options under consideration is an air cored superconducting toroidal magnet system consisting of a long barrel toroid with small and cap toroids inserted in it to provide high resolution at high pseudorapidity. The design of the barrel toroid has been studied over the past two years and the design outline is given in a Saclay Report. More recently consideration has been given to an end cap toroid system which is based on air cored superconducting coils. This report presents the basic engineering design of such a system, the proposals for fabrication, assembly and installation, and an outline cost estimate for one end cap is presented in Appendix 1.

  18. Low AC Loss in a 3 kA HTS Cable of the Dutch Project

    DEFF Research Database (Denmark)

    Chevtchenko, Oleg; Zuijderduin, Roy; Smit, Johan

    2012-01-01

    Requirements for a 6km long high temperature superconducting (HTS) AC power cable of the Amsterdam project are: a cable has to fit in an annulus of 160mm, with two cooling stations at the cable ends only. Existing solutions for HTS cables would lead to excessively high coolant pressure drop in th...

  19. Decay and Snapback in Superconducting Accelerator Magnets

    CERN Document Server

    Haverkamp, M

    2003-01-01

    This thesis deals with the explanation and compensation of the effects 'decay' and 'snapback' in superconducting accelerator magnets, in particular in those used in the new Large Hardron Collider at CERN. During periods of constant magnet excitation, as for example during the injection of particles in the storage ring, the magnetic field in superconducting accelerator magnets shows a decay behavior. As soon as the particles are accelerated, the magnets are ramped, and the magnetic field 'snaps back' to the original hysteresis curve. Decay and snapback affect the beam in the machine and have tobe compensated precisely in order to avoid losses of particles. The research presented in this thesis is a step towards a better understanding of 'decay' and 'snapback' in superconducting particle accelerators. The thesis provides tools for the prediction and compensation of both effects in the magnets, and for the analysis of correlations between different magnet parameters.

  20. A novel miniature superconducting converter for 1 kA magnets

    NARCIS (Netherlands)

    Chevtchenko, O.A.; Krooshoop, Hendrikus J.G.; ten Kate, Herman H.J.; Fedorovsky, Michael A.

    1996-01-01

    A miniature full-wave converter to control the current of a superconducting magnet is developed and tested in our institutes. Typical design values of the device are: AC voltage of 35 V, current of 7 A, and frequency 50-60 Hz; DC voltage o f f 0.2 V, and current of * 1 kA. An efficiency is better

  1. Electric machines

    CERN Document Server

    Gross, Charles A

    2006-01-01

    BASIC ELECTROMAGNETIC CONCEPTSBasic Magnetic ConceptsMagnetically Linear Systems: Magnetic CircuitsVoltage, Current, and Magnetic Field InteractionsMagnetic Properties of MaterialsNonlinear Magnetic Circuit AnalysisPermanent MagnetsSuperconducting MagnetsThe Fundamental Translational EM MachineThe Fundamental Rotational EM MachineMultiwinding EM SystemsLeakage FluxThe Concept of Ratings in EM SystemsSummaryProblemsTRANSFORMERSThe Ideal n-Winding TransformerTransformer Ratings and Per-Unit ScalingThe Nonideal Three-Winding TransformerThe Nonideal Two-Winding TransformerTransformer Efficiency and Voltage RegulationPractical ConsiderationsThe AutotransformerOperation of Transformers in Three-Phase EnvironmentsSequence Circuit Models for Three-Phase Transformer AnalysisHarmonics in TransformersSummaryProblemsBASIC MECHANICAL CONSIDERATIONSSome General PerspectivesEfficiencyLoad Torque-Speed CharacteristicsMass Polar Moment of InertiaGearingOperating ModesTranslational SystemsA Comprehensive Example: The ElevatorP...

  2. Suppression of guidance force decay of HTS bulk exposed to AC magnetic field perturbation in a maglev vehicle system

    International Nuclear Information System (INIS)

    Zhang Longcai; Wang Suyu; Wang Jiasu

    2009-01-01

    Superconducting maglev vehicle was one of the most promising applications of HTS bulks. In such a system, the HTS bulks were always exposed to AC external magnetic field, which was generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, it was observed that the guidance force of the YBCO bulk over the NdFdB guideway used in the high-temperature superconducting maglev vehicle system was decayed by the application of the AC external magnetic field. In this paper, we adopted a method to suppress the decay by altering the field-cooled height of the bulk. From the experimental results, it was found that the decay rate of the guidance force was smaller at lower field-cooled height. So we could suppress the guidance force decay of HTS bulk exposed to AC external magnetic field perturbation in the maglev vehicle system by reducing the field-cooled height of the bulk. Furthermore, all the experimental results in this paper were explained based on Bean critical-state model.

  3. Suppression of guidance force decay of HTS bulk exposed to AC magnetic field perturbation in a maglev vehicle system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Longcai, E-mail: zhlcai2000@163.co [College of Air Traffic Management, Civil Aviation Flight University of China, Guanghan, Sichuan 618307 (China); Wang Suyu; Wang Jiasu [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China)

    2009-07-01

    Superconducting maglev vehicle was one of the most promising applications of HTS bulks. In such a system, the HTS bulks were always exposed to AC external magnetic field, which was generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, it was observed that the guidance force of the YBCO bulk over the NdFdB guideway used in the high-temperature superconducting maglev vehicle system was decayed by the application of the AC external magnetic field. In this paper, we adopted a method to suppress the decay by altering the field-cooled height of the bulk. From the experimental results, it was found that the decay rate of the guidance force was smaller at lower field-cooled height. So we could suppress the guidance force decay of HTS bulk exposed to AC external magnetic field perturbation in the maglev vehicle system by reducing the field-cooled height of the bulk. Furthermore, all the experimental results in this paper were explained based on Bean critical-state model.

  4. Characteristics of the joint mini-model high temperature superconducting cable

    International Nuclear Information System (INIS)

    Kim, H.; Sim, K.; Cho, J.; Kim, S.; Kim, J.H.; Jung, H.Y.

    2008-01-01

    To obtain realistic data on the high temperature superconducting (HTS) power cable, 3-phase 100 m long, 22.9 kV class HTS power transmission cable system have been developed by Korea Electrotechnology Research Institute (KERI) and LS cable Ltd. that is one of 21st Century Frontier Project in Korea. This cable was installed at Go-chang testing site of Korea Electric Power Corporation (KEPCO). For the application of the HTS power cable joint is very important to ensure the performance. Therefore, this paper gives some investigation of AC loss, critical current and joint resistance in jointed HTS tape. We experimentally showed that the influence of joint resistance on AC loss by using several joint methods. Finally, we are measured critical current, AC loss and jointed resistance for the manufactured mini-model cable

  5. Possibility of persistent voltage observation in a system of asymmetric superconducting rings

    International Nuclear Information System (INIS)

    Burlakov, A.A.; Gurtovoi, V.L.; Ilin, A.I.; Nikulov, A.V.; Tulin, V.A.

    2012-01-01

    The possibility of observing persistent voltage in superconducting rings of different arm widths is experimentally investigated. It was previously found that switching of the arms between superconducting and normal states by an AC current induces DC voltage oscillation in the magnetic field with a period corresponding to the flux quantum inside the ring. We used systems with a large number of asymmetric rings connected in series to investigate the possibility of observing this quantum phenomenon near the superconducting transition, where thermal fluctuations lead to switching of ring segments without an external influence and the persistent current is much smaller than in the superconducting state. -- Highlights: ► A possibility to observe the persistent voltage is investigated experimentally. ► The persistent voltage is a DC voltage observed at thermodynamic equilibrium. ► It oscillates in magnetic field like the persistent current in superconducting ring. ► The period of the oscillations corresponds to the flux quantum inside the ring. ► The quantum oscillations of the DC voltage were observed on asymmetric rings.

  6. Present and future superconducting cyclotrons

    International Nuclear Information System (INIS)

    Nolen, J.A. Jr.

    1987-01-01

    This paper begins with a brief review of the status of present superconducting (SC) cyclotron projects, including the two which are currently operating and the six which are under construction. The next section summarizes the main features shared by five of these machines, while the third section presents recent developments and new concepts introduced in the other three ''second generation'' SC cyclotrons. Projects in early stages of development are discussed in the fourth section

  7. Eccentric superconducting rf cavity separator structure

    International Nuclear Information System (INIS)

    Aggus, J.R.; Giordano, S.T.; Halama, H.J.

    1976-01-01

    An accelerator apparatus is described having an eccentric-shaped, iris-loaded deflecting cavity for an rf separator for a high energy high momentum, charged particle accelerator beam. In one embodiment, the deflector is superconducting, and the apparatus of this invention provides simplified machining and electron beam welding techniques. Model tests have shown that the electrical characteristics provide the desired mode splitting without adverse effects

  8. The LHC machine Exhibition Lepton-Photon 2001

    CERN Multimedia

    2001-01-01

    The LHC will enable the study of proton-proton and ion-ion collisions. The existing chain of injectors (LINAC, booster, PS, SPS) will provide the necessary particles. The LHC superconducting magnets will generate the highest magnetic fields ever reached in an accelerator of this scale. The dipoles and quadrupoles will be interconnected so as to form a continuous cryogenic "pipe" installed in the 27 km-long LEP/LHC tunnel with its separate cryoline. The superconducting RF accelerating cavities, along with the beam cleaning and beam dump systems, will complete the machine.

  9. Niobium superconducting rf cavity fabrication by electrohydraulic forming

    CERN Document Server

    Cantergiani, E.; Léaux, F.; Perez Fontenla, A.T.; Prunet, S.; Dufay-Chanat, L.; Koettig, T.; Bertinelli, F.; Capatina, O.; Favre, G.; Gerigk, F.; Jeanson, A. C.; Fuzeau, J.; Avrillaud, G.; Alleman, D.; Bonafe, J.; Marty, P.

    2016-01-01

    Superconducting rf (SRF) cavities are traditionally fabricated from superconducting material sheets or made of copper coated with superconducting material, followed by trim machining and electron-beam welding. An alternative technique to traditional shaping methods, such as deep-drawing and spinning, is electrohydraulicforming (EHF). InEHF, half-cells areobtainedthrough ultrahigh-speed deformation ofblank sheets, using shockwaves induced in water by a pulsed electrical discharge. With respect to traditional methods, such a highly dynamic process can yield interesting results in terms of effectiveness, repeatability, final shape precision, higher formability, and reduced springback. In this paper, the first results of EHFon high purity niobium are presented and discussed. The simulations performed in order to master the multiphysics phenomena of EHF and to adjust its process parameters are presented. The microstructures of niobium half- cells produced by EHFand by spinning have been compared in terms of damage...

  10. Operating Regions of Adjustable-Speed Units with Doubly Fed Machines

    Czech Academy of Sciences Publication Activity Database

    Schreier, Luděk; Chomát, Miroslav; Bendl, Jiří

    2004-01-01

    Roč. 49, č. 2 (2004), s. 119-136 ISSN 0001-7043 R&D Projects: GA AV ČR IAA2057102 Keywords : AC machines * adjustable-speed systems * doubly fed machine Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  11. Design study of an AC power supply system in JT-60SA

    International Nuclear Information System (INIS)

    Shimada, Katsuhiro; Baulaigue, Olivier; Cara, Philippe; Coletti, Alberto; Coletti, Roberto; Matsukawa, Makoto; Terakado, Tsunehisa; Yamauchi, Kunihito

    2011-01-01

    In the initial research phase of JT-60SA, which is the International Thermonuclear Experimental Reactor (ITER) satellite Tokamak with superconducting toroidal and poloidal magnetic field coils, the plasma heating operation of 30 MW-60 s or 20 MW-100 s is planned for 5.5 MA single null divertor plasmas. To achieve this operation, AC power source of the medium voltage of 18 kV and ∼7 GJ has to be provided in total to the poloidal field coil power supplies and additional heating devices such as neutral beam injection (NBI) and electron cyclotron radio frequency (ECRF). In this paper, the proposed AC power supply system in JT-60SA was estimated from the view point of available power, and harmonic currents based on the standard plasma operation scenario during the initial research phase. This AC power supply system consists of the reused JT-60 power supply facilities including motor generators with flywheel, AC breakers, harmonic filters, etc., to make it cost effective. In addition, the conceptual design of the upgraded AC power supply system for the ultimate heating power of 41 MW-100 s in the extended research phase is also described.

  12. AC power losses in Bi-2223/Ag HTS tapes

    International Nuclear Information System (INIS)

    Savvides, N.; Reilly, D.; Mueller, K.-H.; Herrmann, J.

    1998-01-01

    Full text: We report measurements at 77 K of the transport ac losses of Bi-2223/Ag composite tapes. The investigated tapes vary from single filament to multifilament construction and include both conventional tapes and other conductor shapes with twisted filaments. The self-field ac losses were determined at 77 K and 60 Hz as a function of ac current amplitude (0 - 100 A). We observe different behaviour among tapes depending on their quality and strain history. For 'good' virgin tapes the experimental data are well described by the Norris equations for the dependence of power loss P on the amplitude I m of the transport current. The data of good monofilament tapes are fitted to the Norris equation P ∼ I m n for an elliptical cross section (ie. n = 3) and the data of good multifilament tapes are fitted to the Norris equation for a rectangular strip (ie. n = 4). Many specimens, however, show a range of behaviour with lower values of n. Based on our work on the effect of strain on the dc transport properties of tapes, we carried out detailed investigations of the effect of controlled applied bend strain on the ac loss. Our results show that irreversible damage to superconducting filaments (ie. cracks) cause the ac loss to rise and n to decrease with increasing strain. In addition, applied strains much greater than the irreversible strain limit cause the ac loss to increase by several orders of magnitude and become ohmic in character with n = 2. Theoretical work is in progress to model the observed behaviour

  13. The complex ac susceptibility of superconducting Y-Ba-CuO thin film and bulk samples

    International Nuclear Information System (INIS)

    Lobotka, P.; Goemoery, F.

    1988-01-01

    Complex ac susceptibility measurements as function of temperature on Y-Ba-CuO superconductors are reported. A strong dependence of the susceptibility curves on the ac field magnitude and little influence of the superimposed dc field are observed on both, thin film and bulk samples. The susceptibilities of these materials are frequency independent in the range 30 to 7200 Hz what demonstrates the negligible role of eddy currents. A second peak in the imaginary part of susceptibility is observed in the bulk sample at higher levels of ac field. This implies the existence of another component in the sample with higher T c and lower losses. (author)

  14. Vacuum system design for a superconducting X-ray lithography light source

    International Nuclear Information System (INIS)

    Schuchman, J.C.

    1990-01-01

    A superconducting electron storage ring for X-ray lithography (SXLS) is to be built at Brookhaven National Laboratory (BNL). The goal is to design and construct a light source specifically dedicated to X-ray lithography production and which would be used as a prototype in a technology transfer to American industry. The machine will be built in two phases: phase I, a low energy ring (200 MeV, 500 mA) using all room temperature magnets which will be used primarily for low energy injection studies. Phase II will be a full energy machine (690 MeV, 500 mA) where the room temperature 180 0 dipole magnets of phase I will be replaced with superconducting magnets. The machine, with a racetrack shape and a circumference of 8.5 m, is designed to be portable and replaceable as a single unit. This paper will discuss the vacuum system design for both phases; i.e. gas desorption, warm bore vs cold bore, ion trapping, clearing electrodes, and diagnostic instrumentation. (author)

  15. Recovery time of high temperature superconducting tapes exposed in liquid nitrogen

    International Nuclear Information System (INIS)

    Sheng, Jie; Zeng, Weina; Yao, Zhihao; Zhao, Anfeng; Hu, Daoyu; Hong, Zhiyong

    2016-01-01

    Highlights: • A novel method based on a sequence of AC pulses is presented. • Liquid nitrogen temperature is used as criterion to judge whether the sample has recovered. • Recovery time of some tape doesn't increase with the amplitude of fault current. • This phenomenon is caused by boiling heat transfer process of liquid nitrogen. • This phenomenon can be used in optimizing both the limiting rate and reclosing system. - Abstract: The recovery time is a crucial parameter to high temperature superconducting tapes, especially in power applications. The cooperation between the reclosing device and the superconducting facilities mostly relies on the recovery time of the superconducting tapes. In this paper, a novel method is presented to measure the recovery time of several different superconducting samples. In this method criterion used to judge whether the sample has recovered is the liquid nitrogen temperature, instead of the critical temperature. An interesting phenomenon is observed during the testing of superconducting samples exposed in the liquid nitrogen. Theoretical explanations of this phenomenon are presented from the aspect of heat transfer. Optimization strategy of recovery characteristics based on this phenomenon is also briefly discussed.

  16. Modelling and measurement of ac loss in BSCCO/Ag-tape windings

    International Nuclear Information System (INIS)

    Oomen, M P; Nanke, R; Leghissa, M

    2003-01-01

    High-temperature superconducting (HTS) transformers promise decreased weight and volume and higher efficiency. A 1 MVA HTS railway transformer was built and tested at Siemens AG. This paper deals with the prediction of ac loss in the BSCCO/Ag-tape windings. In a railway transformer the tape carries ac current in alternating field, the temperature differs from 77 K, tapes are stacked or cabled and overcurrents and higher harmonics occur. In ac-loss literature these issues are treated separately, if at all. We have developed a model that predicts the ac loss in sets of BSCCO/Ag-tape coils, and deals with the above-mentioned issues. The effect of higher harmonics on the loss in HTS tapes is considered for the first time. The paper gives a complete overview of the model equations and required input parameters. The model is validated over a wide range of the input parameters, using the measured critical current and ac loss of single tapes, single coils and sets of coils in the 1 MVA transformer. An accuracy of around 25% is achieved in all relevant cases. Presently the model is developed further, in order to describe other HTS materials and other types of applications

  17. Conceptual design of superconducting magnet systems for the Argonne Tokamak Experimental Power Reactor

    International Nuclear Information System (INIS)

    Wang, S.T.; Turner, L.R.; Mills, F.E.; DeMichele, D.W.; Smelser, P.; Kim, S.H.

    1976-01-01

    As an integral effort in the Argonne Tokamak Experimental Power Reactor Conceptual Design, the conceptual design of a 10-tesla, pure-tension superconducting toroidal-field (TF) coil system has been developed in sufficient detail to define a realistic design for the TF coil system that could be built based upon the current state of technology with minimum technological extrapolations. A conceptual design study on the superconducting ohmic-heating (OH) coils and the superconducting equilibrium-field (EF) coils were also completed. These conceptual designs are developed in sufficient detail with clear information on high current ac conductor design, cooling, venting provision, coil structural support and zero loss poloidal coil cryostat design. Also investigated is the EF penetration into the blanket and shield

  18. Prototype superconducting magnet for the FFAG accelerator

    International Nuclear Information System (INIS)

    Obana, T.; Ogitsu, T.; Yamamoto, A.; Yoshimoto, M.; Mori, Y.; Fujii, T.; Iwasa, M.; Orikasa, T.

    2006-01-01

    A study of a superconducting magnet for the Fixed Field Alternating Gradient (FFAG) accelerator has been performed. The FFAG accelerator requires static magnetic field, and it is suitable for superconducting magnet applications, because problems associated with time varying magnetic field such as eddy current loss can be eliminated. The superconducting magnet, which can generate high magnetic field, is possible to realize a higher beam energy with a given accelerator size or the size to be smaller for a given beam energy. The FFAG accelerator magnet is demanded to have a complicated nonlinear magnetic field with high accuracy. As a first prototype superconducting coil, the coil configuration which consists of left-right asymmetric cross-section and large aperture has been designed. The prototype coil has been successfully developed by using a 6-axis Computer Numerical Control (CNC) winding machine. The magnetic field of the prototype coil has been demonstrated in warm measurement. As a consequence, the technical feasibility has been verified with the prototype coil development and the performance test. In addition, the technology components developed in the prototype coil have a possibility to transfer to a fusion magnet

  19. Technical tasks in superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kenji [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    1997-11-01

    The feature of superconducting rf cavities is an extremely small surface resistance on the wall. It brings a large energy saving in the operation, even those are cooled with liquid helium. That also makes possible to operate themselves in a higher field gradient comparing to normal conducting cavities, and brings to make accelerators compact. These merits are very important for the future accelerator engineering which is planed at JAERI for the neutron material science and nuclear waste transmutation. This machine is a high intensity proton linac and uses sc cavities in the medium and high {beta} sections. In this paper, starting R and D of proton superconducting cavities, several important technical points which come from the small surface resistance of sc cavities, are present to succeed it and also differences between the medium and high - {beta} structures are discussed. (author)

  20. Superconducting heterostructures: from antipinning to pinning potentials

    International Nuclear Information System (INIS)

    Carreira, S J; Chiliotte, C; Bekeris, V; Rosen, Y J; Monton, C; Schuller, Ivan K

    2014-01-01

    We study vortex lattice dynamics in a heterostructure that combines two type-II superconductors: a niobium film and a dense triangular array of submicrometric vanadium (V) pillars. Magnetic ac susceptibility measurements reveal a sudden increase in ac penetration, related to an increase in vortex mobility above a magnetic field, H ∗ (T), that decreases linearly with temperature. Additionally, temperature independent matching effects that occur when the number of vortices in the sample is an integer of the number of V pillars, strongly reduce vortex mobility, and were observed for the first and second matching fields, H 1 and H 2 . The angular dependence of H 1 , H 2 and H ∗ (T) shows that matching is determined by the normal applied field component, while H ∗ (T) is independent of the applied field orientation. This important result identifies H ∗ (T) with the critical field boundary for the normal to superconducting transition of V pillars. Below H ∗ (T), superconducting V pillars repel vortices, and the array becomes an ‘antipinning’ landscape that is more effective in reducing vortex mobility than the ‘pinning’ landscape of the normal V sites above H ∗ (T). Matching effects are observed both below and above H ∗ (T), implying the presence of ordered vortex configurations for ‘antipinning’ or ‘pinning’ arrays. (paper)

  1. Calculating transport AC losses in stacks of high temperature superconductor coated conductors with magnetic substrates using FEM

    International Nuclear Information System (INIS)

    Ainslie, Mark D.; Flack, Tim J.; Campbell, Archie M.

    2012-01-01

    Properties of stacks of HTS coated conductors with and without a magnetic substrate. Non-magnetic substrate model is consistent with existing methods. Presence of a magnetic substrate increases the total AC loss of the stack. Differences and similarities between certain tapes within stacks are explained. Ferromagnetic loss of substrate negligible in most cases except small currents/fields. In this paper, the authors investigate the electromagnetic properties of stacks of high temperature superconductor (HTS) coated conductors with a particular focus on calculating the total transport AC loss. The cross-section of superconducting cables and coils is often modeled as a two-dimensional stack of coated conductors, and these stacks can be used to estimate the AC loss of a practical device. This paper uses a symmetric two dimensional (2D) finite element model based on the H formulation, and a detailed investigation into the effects of a magnetic substrate on the transport AC loss of a stack is presented. The number of coated conductors in each stack is varied from 1 to 150, and three types of substrate are compared: non-magnetic weakly magnetic and strongly magnetic. The non-magnetic substrate model is comparable with results from existing models for the limiting cases of a single tape (Norris) and an infinite stack (Clem). The presence of a magnetic substrate increases the total AC loss of the stack, due to an increased localized magnetic flux density, and the stronger the magnetic material, the further the flux penetrates into the stack overall. The AC loss is calculated for certain tapes within the stack, and the differences and similarities between the losses throughout the stack are explained using the magnetic flux penetration and current density distributions in those tapes. The ferromagnetic loss of the substrate itself is found to be negligible in most cases, except for small magnitudes of current. Applying these findings to practical applications, where AC

  2. Low field critical currents and ac losses of thin film niobium--tin superconductors

    International Nuclear Information System (INIS)

    Howard, R.E.

    1977-01-01

    The results of a study of the low field critical current and ac loss properties of niobium-tin thin films and layered composites fabricated by electron-beam coevaporation are presented. Particular emphasis is placed upon determining the suitability of this material for use as a conductor in a superconducting power transmission line. Chapter I contains a summary of this work and its major results together with an introduction to the scientific and engineering concepts associated with a superconducting power transmission line. Chapter II is a discussion of the physics of current transport and the associated loss mechanisms in a type-II superconductor. Chapter III gives the details of the electron-beam coevaporation technique developed to fabricate the samples for this study. Also discussed in this chapter are the effects of the evaporation conditions on the growth morphology of the niobium-tin films. Chapter IV presents the details of the experimental techniques developed to measure the ac loss and critical current in these samples as a function of temperature. Chapter V shows the dependence of the critical current of these films and composites on temperature, magnetic field, and on the number of artificially introduced pinning centers in the layered composites. Experimental results are also presented concerning the stability of these conductors against flux jumps. Chapter VI is a discussion of the ac losses in these samples. Detailed comparisons are made between the measured loss and the predictions of the critical state model

  3. Thermal instability and current-voltage scaling in superconducting fault current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Zeimetz, B [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Tadinada, K [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Eves, D E [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Coombs, T A [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Evetts, J E [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Campbell, A M [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom)

    2004-04-01

    We have developed a computer model for the simulation of resistive superconducting fault current limiters in three dimensions. The program calculates the electromagnetic and thermal response of a superconductor to a time-dependent overload voltage, with different possible cooling conditions for the surfaces, and locally variable superconducting and thermal properties. We find that the cryogen boil-off parameters critically influence the stability of a limiter. The recovery time after a fault increases strongly with thickness. Above a critical thickness, the temperature is unstable even for a small applied AC voltage. The maximum voltage and maximum current during a short fault are correlated by a simple exponential law.

  4. Development of a new type of three-component composite superconducting wire

    International Nuclear Information System (INIS)

    Onishi, T.

    1977-01-01

    A new type of multifilamentary composite superconducting wire is described. This wire consists of seven filaments, each of which is a fine tubular Nb 50% Ti wire, filled with high purity aluminium and embedded in a cupronickel matrix. The results of experiments carried out on the stability and ac losses of this wire are presented. (author)

  5. Material machining with pseudo-spark electron beams

    International Nuclear Information System (INIS)

    Benker, W.; Christiansen, J.; Frank, K.; Gundel, H.; Redel, T.; Stetter, M.

    1989-01-01

    The authors give a brief description of the production of pseudo-spark (low pressure gas discharge) electron beams. They illustrate the use of these electron beams for machining not only conducting, semiconducting and insulating materials, but also thin layers of such materials as high temperature superconducting ceramics

  6. ANL experimental program for pulsed superconducting coils

    International Nuclear Information System (INIS)

    Wang, S.T.; Kim, S.H.; Praeg, W.F.; Krieger, C.I.

    1978-01-01

    Argonne National Laboratory (ANL) had recognized the clear advantage of a superconducting ohmic-heating (OH) coil and started in aggressive development program in FY 1977. The main objectives for FY 1977 are to develop cryostable basic cable configurations with reasonably low ac losses, to develop 12 kA cryostable cable, using it to design and build a 1.5 MJ pulsed coil, and to develop a rather inexpensive large fiberglass reinforced helium cryostat for the 1.5 MJ pulsed coil. The principal objective in building the 1.5 MJ ac coil is to demonstrate ac cryostability of a large coil ranging from 2 T/s up to 12 T/s. Another objective in the pulsed coil program is to determine the feasibility of parallel coil operation in order to avoid excessive voltage and current requirements and to minimize the number of turns for the equilibrium field (EF) coils, should the EF coils be connected in parallel with the OH coils. A two-coil section model using the 11 kA cable will be built and tested

  7. ANL experimental program for pulsed superconducting coils

    International Nuclear Information System (INIS)

    Wang, S.T.; Kim, S.H.; Praeg, W.F.; Krieger, C.I.

    1977-01-01

    Argonne National Laboratory (ANL) had recognized the clear advantage of a superconducting ohmic-heating (OH) coil and started an aggressive development program in FY 1977. The main objectives for FY 1977 are to develop cryostable basic cable configurations with reasonably low ac losses, to develop 12 kA cryostable cable, using it to design and build a 1.5 MJ pulsed coil, and to develop a rather inexpensive large fiberglass reinforced helium cryostat for the 1.5 MJ pulsed coil. The principal objective in building the 1.5 MJ ac coil is to demonstrate ac cryostability of a large coil ranging from 2 T/s up to 12 T/s. Another objective in the pusled coil program is to determine the feasibility of parallel coil operation in order to avoid excessive voltage and current requirements and to minimize the number of turns for the equilibrium field (EF) coils, should the EF coils be connected in parallel with the OH coils. A two-coil section model using the 11 kA cable will be built and tested

  8. Superconducting magnet systems in EPR designs

    International Nuclear Information System (INIS)

    Knobloch, A.F.

    1976-10-01

    Tokamak experiments have reached a stage where large scale application of superconductors can be envisaged for machines becoming operational within the next decade. Existing designs for future devices already indicate some of the tasks and problems associated with large superconducting magnet systems. Using this information the coming magnet system requirements are summarized, some design considerations given and in conclusion a brief survey describes already existing Tokamak magnet development programs. (orig.) [de

  9. Polaron effects on the dc- and ac-tunneling characteristics of molecular Josephson junctions

    Science.gov (United States)

    Wu, B. H.; Cao, J. C.; Timm, C.

    2012-07-01

    We study the interplay of polaronic effect and superconductivity in transport through molecular Josephson junctions. The tunneling rates of electrons are dominated by vibronic replicas of the superconducting gap, which show up as prominent features in the differential conductance for the dc and ac current. For relatively large molecule-lead coupling, a features that appears when the Josephson frequency matches the vibron frequency can be identified with an over-the-gap structure observed by Marchenkov [Nat. Nanotech. 1748-338710.1038/nnano.2007.2182, 481 (2007)]. However, we are more concerned with the weak-coupling limit, where resonant tunneling through the molecular level dominates. We find that certain features involving both Andreev reflection and vibron emission show an unusual shift of the bias voltage V at their maximum with the gate voltage Vg as V˜(2/3)Vg. Moreover, due to the polaronic effect, the ac Josephson current shows a phase shift of π when the bias eV is increased by one vibronic energy quantum ℏωv. This distinctive even-odd effect is explained in terms of the different sign of the coupling to vibrons of electrons and of Andreev-reflected holes.

  10. ac loss and dc critical current densities of Nb3Sn tapes by the solid state diffusion process

    International Nuclear Information System (INIS)

    Suenaga, M.; Klamut, C.; Bussiere, J.F.

    1976-01-01

    The effects of metallurgical processing on 60 Hz ac losses and dc critical currents in Nb 3 Sn tapes fabricated by the solid state diffusion technique were investigated. An addition of Al to the Cu--Sn alloy for the matrix resulted in large reduction in the ac losses of Nb 3 Sn tapes, but the highest linear critical current densities were observed in Nb 3 Sn tapes produced with a Nb-1 wt percent Zr core in a Cu-13 wt percent Sn matrix. Values of the losses and the critical currents in these tapes can meet the present requirements for the ac superconducting power cables

  11. Piotron at SIN - a large superconducting double torus spectrometer

    International Nuclear Information System (INIS)

    Horvath, I.; Vecsey, G.; Zellweger, J.

    1981-01-01

    A test facility for radiation therapy with negative /pi/-mesons was constructed in Switzerland. The facility is a large double torus spectrometer similar to the Stanford design. For variation of stopping depth different momenta are selected by variation of the magnetic field. Superconducting ac magnets are necessary for tumor scanning and represent a major part of such a facility. Main design features and performance are reported. 10 refs

  12. Proposal for the award of a contract, without competitive tendering, for the supply of two cabling machines for the manufacture of superconducting cable for the LHC main magnets

    CERN Document Server

    2001-01-01

    This document concerns the award of a contract, without competitive tendering, for the supply of two cabling machines for the production of superconducting cable for the LHC main magnets. These cables are of two different types, hereafter referred as Cable 1 and Cable 2. For the reasons set out in this document, the Finance Committee is invited to agree to the negotiation of a contract with SETIC (FR) for the supply of two cabling machines, for a total amount not exceeding 3 200 000 euros (4 948 800 Swiss francs), not subject to revision. The rate of exchange which has been used is that stipulated in the tender. The firm has indicated the following distribution by country of the contract value covered by this adjudication proposal: FR - 100%.

  13. Low-temperature heat capacity of small Nb3Sn polycrystals by ac calorimetry

    International Nuclear Information System (INIS)

    Viswanathan, R.; Johnston, D.C.

    1976-01-01

    It is shown by an ac calorimetry technique that the multiple heat capacity anomalies which occur below the superconducting transition temperature for small polycrystalline Nb 3 Sn samples are intrinsic to these samples. The recent suggestions that shear stresses can account for these results are analyzed for their validity. The dependence of the occurrence of these multiple anomalies upon the thermal history of the samples was investigated

  14. Power applications for superconducting cables in Denmark

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Østergaard, Jacob; Olsen, S. Krüger

    1999-01-01

    In Denmark a growing concern for environmental protection has lead to wishes that the open country is kept free of overhead lines as far as possible. New lines under 100 kV and existing 60/50 kV lines should be established as underground cables. Superconducting cables represent an interesting...... in cases such as transmission of energy into cities and through areas of special interest. The planned large groups of windmills in Denmark generating up to 2000 MVA or more both on dry land and off-shore will be an obvious case for the application of superconducting AC or DC cables. These opportunities...... can be combined with other new technologies such as HVDC light transmission using isolated gate bipolar transistors (IGBTs). The network needed in a system with a substantial wind power generation has to be very strong in order to handle energy fluctuations. Such a network will be possible...

  15. Complex study of transport AC loss in various 2G HTS racetrack coils

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yiran, E-mail: yc315@cam.ac.uk [University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Zhang, Min; Chudy, Michal; Matsuda, Koichi; Coombs, Tim [University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom)

    2013-04-15

    Highlights: ► Comparing transport AC losses of two types of 2G HTS racetrack coils. ► The magnetic substrate in the MAG RABITS coil is the main difference. ► Experimental data agree well with simulation results. ► The transport AC loss in the MAG RABITS coil is 36% higher than that in the IBAD coil. ► It is better to keep all the substrate non-magnetic. -- Abstract: HTS racetrack coils are becoming important elements of an emerging number of superconducting devices such as generators or motors. In these devices the issue of AC loss is crucial, as performance and cooling power are derived from this quantity. This paper presents a comparative study of transport AC loss in two different types of 2G HTS racetrack coils. In this study, both experimental measurements and computer simulation approaches were employed. All the experiments were performed using classical AC electrical method. The finite-element computer model was used to estimate electromagnetic properties and calculate transport AC loss. The main difference between the characterized coils is covered inside tape architectures. While one coil uses tape based on RABITS magnetic substrate, the second coil uses a non-magnetic tape. Ferromagnetic loss caused by a magnetic substrate is an important issue involved in the total AC loss. As a result, the coil with the magnetic substrate surprised with high AC loss and rather low performance.

  16. The achievements of the Z-machine

    International Nuclear Information System (INIS)

    Larousserie, D.

    2008-01-01

    The ZR-machine that represents the latest generation of Z-pinch machines has recently begun preliminary testing before its full commissioning in Albuquerque (Usa). During its test the machine has well operated with electrical currents whose intensities of 26 million Ampere are already 2 times as high as the intensity of the operating current of the previous Z-machine. In 2006 the Z-machine reached temperatures of 2 billions Kelvin while 100 million Kelvin would be sufficient to ignite thermonuclear fusion. In fact the concept of Z-pinch machines was imagined in the fifties but the technological breakthrough that has allowed this recent success and the reborn of Z-machine, was the replacement of gas by an array of metal wires through which the electrical current flows and vaporizes it creating an imploding plasma. It is not well understood why Z-pinch machines generate far more radiation than theoretically expected. (A.C.)

  17. Pressure dependence of the superconducting transition temperature of Rb3C60 up to 20 kbar

    International Nuclear Information System (INIS)

    Bud'ko, S.L.; Meng, R.L.; Chu, C.W.; Hor, P.H.

    1991-01-01

    AC susceptibility measurements of Rb 3 C 60 under hydrostatic pressure up to 20 kbar are reported. The superconducting transition temperature (T c ) decreases linearly under pressure with the pressure derivative dT c /dP = -0.78 K degrees/kbar

  18. Study on AC loss measurements of HTS power cable for standardizing

    Science.gov (United States)

    Mukoyama, Shinichi; Amemiya, Naoyuki; Watanabe, Kazuo; Iijima, Yasuhiro; Mido, Nobuhiro; Masuda, Takao; Morimura, Toshiya; Oya, Masayoshi; Nakano, Tetsutaro; Yamamoto, Kiyoshi

    2017-09-01

    High-temperature superconducting power cables (HTS cables) have been developed for more than 20 years. In addition of the cable developments, the test methods of the HTS cables have been discussed and proposed in many laboratories and companies. Recently the test methods of the HTS cables is required to standardize and to common in the world. CIGRE made the working group (B1-31) for the discussion of the test methods of the HTS cables as a power cable, and published the recommendation of the test method. Additionally, IEC TC20 submitted the New Work Item Proposal (NP) based on the recommendation of CIGRE this year, IEC TC20 and IEC TC90 started the standardization work on Testing of HTS AC cables. However, the individual test method that used to measure a performance of HTS cables hasn’t been established as world’s common methods. The AC loss is one of the most important properties to disseminate low loss and economical efficient HTS cables in the world. We regard to establish the method of the AC loss measurements in rational and in high accuracy. Japan is at a leading position in the AC loss study, because Japanese researchers have studied on the AC loss technically and scientifically, and also developed the effective technologies for the AC loss reduction. The JP domestic commission of TC90 made a working team to discussion the methods of the AC loss measurements for aiming an international standard finally. This paper reports about the AC loss measurement of two type of the HTS conductors, such as a HTS conductor without a HTS shield and a HTS conductor with a HTS shield. The AC loss measurement method is suggested by the electrical method..

  19. Magnetic response and critical current properties of mesoscopic-size YBCO superconducting samples

    International Nuclear Information System (INIS)

    Lisboa-Filho, P N; Deimling, C V; Ortiz, W A

    2010-01-01

    In this contribution superconducting specimens of YBa 2 Cu 3 O 7-δ were synthesized by a modified polymeric precursor method, yielding a ceramic powder with particles of mesoscopic-size. Samples of this powder were then pressed into pellets and sintered under different conditions. The critical current density was analyzed by isothermal AC-susceptibility measurements as a function of the excitation field, as well as with isothermal DC-magnetization runs at different values of the applied field. Relevant features of the magnetic response could be associated to the microstructure of the specimens and, in particular, to the superconducting intra- and intergranular critical current properties.

  20. Magnetic response and critical current properties of mesoscopic-size YBCO superconducting samples

    Energy Technology Data Exchange (ETDEWEB)

    Lisboa-Filho, P N [UNESP - Universidade Estadual Paulista, Grupo de Materiais Avancados, Departamento de Fisica, Bauru (Brazil); Deimling, C V; Ortiz, W A, E-mail: plisboa@fc.unesp.b [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, Sao Carlos (Brazil)

    2010-01-15

    In this contribution superconducting specimens of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were synthesized by a modified polymeric precursor method, yielding a ceramic powder with particles of mesoscopic-size. Samples of this powder were then pressed into pellets and sintered under different conditions. The critical current density was analyzed by isothermal AC-susceptibility measurements as a function of the excitation field, as well as with isothermal DC-magnetization runs at different values of the applied field. Relevant features of the magnetic response could be associated to the microstructure of the specimens and, in particular, to the superconducting intra- and intergranular critical current properties.

  1. Development of an air coil superconducting fault current limiter

    Energy Technology Data Exchange (ETDEWEB)

    Naeckel, Oliver

    2016-07-01

    Electrical power grids are the lifeline of technical infrastructure and fundamental for industry and modern lives. Fault Currents can disrupt the continuous supply of electrical energy, cause instable grid conditions and damage electrical equipment. The Air Coil Superconducting Fault Current Limiter (AC-SFCL) is a measure to effectively limit fault currents. The concept is investigated and proven experimentally by designing, building and successfully testing a 60 kV, 400 V, z=6% demonstrator.

  2. Demonstration of a helical armature for a superconducting generator

    International Nuclear Information System (INIS)

    Conley, P.L.; Kirtley, J.L. Jr.; Hagman, W.H.; Ula, A.H.M.S.

    1979-01-01

    This is a report on the design, construction and testing of an experimental helical armature for a superconducting geneator. Rated at 60 kVA, this armature was built to be operated in conjunction with the rotor of the first experimental superconducting machine built at MIT. It incorporates, in addition to the helical winding form, a high density edge-brazed end turn geometry, molded bar groups, and silicone fluid coolant and insulation impregnant. Tests showed that the thermal performance of the armature was within reasonable limits, magnetic analyses leading to the computation of reactance and voltage geneation were approximately correct. No abnormal cheating was observed. 9 refs

  3. A facility to test short superconducting accelerator magnets at Fermilab

    International Nuclear Information System (INIS)

    Lamm, M.J.; Hess, C.; Lewis, D.; Jaffery, T.; Kinney, W.; Ozelis, J.P.; Strait, J.; Butteris, J.; McInturff, A.D.; Coulter, K.J.

    1992-10-01

    During the past four years the Superconducting Magnet R ampersand D facility at Fermilab (Lab 2) has successfully tested superconducting dipole, quadrupole, and correction coil magnets less than 2 meters in length for the SSC project and the Tevatron D0/B0 Low-β Insertion. During this time several improvements have been made to the facility that have greatly enhanced its magnet testing capabilities. Among the upgrades have been a new rotating coil and data acquisition system for measuring magnetic fields, a controlled flow liquid helium transfer line using an electronically actuated cryo valve, and stand-alone systems for measuring AC loss and training low current Tevatron correction coil packages. A description of the Lab 2 facilities is presented

  4. Superconductivity

    International Nuclear Information System (INIS)

    Palmieri, V.

    1990-01-01

    This paper reports on superconductivity the absence of electrical resistance has always fascinated the mind of researchers with a promise of applications unachievable by conventional technologies. Since its discovery superconductivity has been posing many questions and challenges to solid state physics, quantum mechanics, chemistry and material science. Simulations arrived to superconductivity from particle physics, astrophysic, electronics, electrical engineering and so on. In seventy-five years the original promises of superconductivity were going to become reality: a microscopical theory gave to superconductivity the cloth of the science and the level of technological advances was getting higher and higher. High field superconducting magnets became commercially available, superconducting electronic devices were invented, high field accelerating gradients were obtained in superconductive cavities and superconducting particle detectors were under study. Other improvements came in a quiet progression when a tornado brought a revolution in the field: new materials had been discovered and superconductivity, from being a phenomenon relegated to the liquid Helium temperatures, became achievable over the liquid Nitrogen temperature. All the physics and the technological implications under superconductivity have to be considered ab initio

  5. Sensorless AC electric motor control robust advanced design techniques and applications

    CERN Document Server

    Glumineau, Alain

    2015-01-01

    This monograph shows the reader how to avoid the burdens of sensor cost, reduced internal physical space, and system complexity in the control of AC motors. Many applications fields—electric vehicles, wind- and wave-energy converters and robotics, among them—will benefit. Sensorless AC Electric Motor Control describes the elimination of physical sensors and their replacement with observers, i.e., software sensors. Robustness is introduced to overcome problems associated with the unavoidable imperfection of knowledge of machine parameters—resistance, inertia, and so on—encountered in real systems. The details of a large number of speed- and/or position-sensorless ideas for different types of permanent-magnet synchronous motors and induction motors are presented along with several novel observer designs for electrical machines. Control strategies are developed using high-order, sliding-mode and quasi-continuous-sliding-mode techniques and two types of observer–controller schemes based on backstepping ...

  6. A continuous winding scheme for superconducting tokamak coils with cable-in-conduit conductor

    International Nuclear Information System (INIS)

    Kim, Sang-ho; Chung, Kie-hyung; Lee, Deok Kyo

    2001-01-01

    Superconducting magnet coils are essential for steady-state or long-pulse operation of tokamaks. In an advanced tokamak, the central solenoid (CS) coils are usually divided into several pairs of modules to provide for an extra plasma shaping capability in addition to those available from the shaping (poloidal field) coils. In the conventional pancake winding scheme of superconducting coils, each coil consists of separate superconducting 'double-pancake' coils connected together in series; however, such joints are not superconducting, which is one of the major disadvantages, especially in pulsed operations. A new type of winding was adopted for the ITER CS coil, which consists of cylindrical shell 'layers' joined in series. A disadvantage of this layer winding is its inability to yield modular coils that can provide certain degree of plasma shaping. Joints can be removed in a coil winding pack with the conventional pancake winding scheme, if the conductor is sufficiently long and the winding machine is properly equipped. The compactness, however, cannot be preserved with this scheme. The winding compactness is important since the radial build of the CS coils is one of the major parameters that determine the machine size. In this paper, we present a continuous winding scheme that requires no joints, allows coil fabrication at minimum dimension, and meets the flux swing requirement and other practical aspects

  7. High power density superconducting rotating machines—development status and technology roadmap

    Science.gov (United States)

    Haran, Kiruba S.; Kalsi, Swarn; Arndt, Tabea; Karmaker, Haran; Badcock, Rod; Buckley, Bob; Haugan, Timothy; Izumi, Mitsuru; Loder, David; Bray, James W.; Masson, Philippe; Stautner, Ernst Wolfgang

    2017-12-01

    Superconducting technology applications in electric machines have long been pursued due to their significant advantages of higher efficiency and power density over conventional technology. However, in spite of many successful technology demonstrations, commercial adoption has been slow, presumably because the threshold for value versus cost and technology risk has not yet been crossed. One likely path for disruptive superconducting technology in commercial products could be in applications where its advantages become key enablers for systems which are not practical with conventional technology. To help systems engineers assess the viability of such future solutions, we present a technology roadmap for superconducting machines. The timeline considered was ten years to attain a Technology Readiness Level of 6+, with systems demonstrated in a relevant environment. Future projections, by definition, are based on the judgment of specialists, and can be subjective. Attempts have been made to obtain input from a broad set of organizations for an inclusive opinion. This document was generated through a series of teleconferences and in-person meetings, including meetings at the 2015 IEEE PES General meeting in Denver, CO, the 2015 ECCE in Montreal, Canada, and a final workshop in April 2016 at the University of Illinois, Urbana-Champaign that brought together a broad group of technical experts spanning the industry, government and academia.

  8. Compound induction electric rotating machine

    Energy Technology Data Exchange (ETDEWEB)

    Decesare, D

    1987-07-28

    The present invention generally relates to dynamo-electric machines cabable of operating in a generator mode or in a motor mode and more specifically, to increased efficiency compound interaction AC and/or DC dynamo-electric machines. This patent describes such a machine having a distributed armature winding in a cylindrical rotor wound to form axial and substantially radial winding portions and including permanent and/or electromagnets to couple magnetic flux into the peripheral or circumferential surface of the rotor, and to provide interaction between a magnetic field formed beyond the rotor axial surfaces and the rotor to thereby enhance the total induction of flux into the rotor for improved, more efficient operation. 28 figs.,

  9. Model of vortex dynamics in superconducting films in two-coil measurements of the coherence length

    Science.gov (United States)

    Lemberger, Thomas; Loh, Yen Lee

    In two-coil measurements on superconducting films, a magnetic field from a small coil is applied to the center of the film. When the amplitude of the ac field is increased, the film undergoes a transition from the ``Meissner'' state to a state with vortices and antivortices. Ultimately, the vortex density matches the applied magnetic field and field screening is negligible. Experimentally, the field at the transition is related to the superconducting coherence length, although a full theory of the relationship is lacking. We show that the mutual inductance between drive and pickup coils, on opposite sides of the film, as a function of ac field amplitude is well-described by a phenomenological model in which vortices and antivortices appear together in the film at the radius where the induced supercurrent is strongest, and then they move through a landscape of moderately strong vortex pinning sites. Work at OSU supported by DOE-Basic Energy Sciences through Grant No. FG02-08ER46533.

  10. The LHC Superconducting RF System

    CERN Document Server

    Boussard, Daniel

    1999-01-01

    The European Laboratory for Particle Physics (CERN), the largest high energy physics laboratory worldwide, is constructing the Large Hadron Collider (LHC) in the existing 27 km circumference LEP (Large Electron Positron) collider tunnel. For the LHC, superconducting cavities, operating at 4.5 K, will provide the required acceleration field for ramping the beam energy up to 7 TeV and for keeping the colliding proton beams tightly bunched. Superconducting cavities were chosen, not only because of their high acceleration field leading to a small contribution to the machine impedance, but also because of their high stored energy which minimises the effects of periodic transient beam loading associated with the high beam intensity (0.5 A). There will be eight single-cell cavities per beam, each delivering 2 MV (5.3 MV/m) at 400 MHz. The cavities themselves are now being manufactured by industrial firms, using niobium on copper technology which gives full satisfaction at LEP. A complete cavity prototype assembly in...

  11. Calculation of AC losses in large HTS stacks and coils

    DEFF Research Database (Denmark)

    Zermeno, Victor; Abrahamsen, Asger Bech; Mijatovic, Nenad

    2012-01-01

    In this work, we present a homogenization method to model a stack of HTS tapes under AC applied transport current or magnetic field. The idea is to find an anisotropic bulk equivalent for the stack of tapes, where the internal alternating structures of insulating, metallic, superconducting...... allowing for overcritical current densities to be considered. The method presented here allowed for a computational speedup factor of up to 2 orders of magnitude when compared to full 2-D simulations taking into account the actual structure of the stacks without compromising accuracy....

  12. Numerical analysis and finite element modelling of an HTS synchronous motor

    Energy Technology Data Exchange (ETDEWEB)

    Ainslie, M.D., E-mail: mda36@cam.ac.u [University of Cambridge, Department of Electrical Engineering (Division B), CAPE Building, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Jiang, Y.; Xian, W.; Hong, Z.; Yuan, W.; Pei, R.; Flack, T.J.; Coombs, T.A. [University of Cambridge, Department of Electrical Engineering (Division B), CAPE Building, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom)

    2010-11-01

    This paper investigates the electromagnetic properties of high-temperature superconductors with a particular focus on the AC loss in coils made from YBCO superconductors. The numerical analysis and finite element modelling of the YBCO superconductors used in Cambridge's superconducting permanent magnet synchronous motor currently in development is described. The stack of tapes in the superconducting coils is modelled using the direct H formulation, a B-dependent critical current density and a bulk approximation. Magnetic boundary conditions for this model are derived from a 2D finite element method (FEM) motor model. The combination of these models allows the total AC loss (combined transport and magnetisation losses) in the HTS coils used in an all-superconducting machine design to be estimated. The raw AC loss figures are compared to the output power of the motor for two test cases, and it is found that the AC loss contributes significantly to the total loss and therefore efficiency. An experimental rig is also described, which has been built in order to test the electromagnetic properties and performance of the motor. It is explained how this rig will be used to investigate the magnetisation of the rotor and carry out AC loss measurements on the stator coils.

  13. Additive Manufactured Superconducting Cavities

    Science.gov (United States)

    Holland, Eric; Rosen, Yaniv; Woolleet, Nathan; Materise, Nicholas; Voisin, Thomas; Wang, Morris; Mireles, Jorge; Carosi, Gianpaolo; Dubois, Jonathan

    Superconducting radio frequency cavities provide an ultra-low dissipative environment, which has enabled fundamental investigations in quantum mechanics, materials properties, and the search for new particles in and beyond the standard model. However, resonator designs are constrained by limitations in conventional machining techniques. For example, current through a seam is a limiting factor in performance for many waveguide cavities. Development of highly reproducible methods for metallic parts through additive manufacturing, referred to colloquially as 3D printing\\x9D, opens the possibility for novel cavity designs which cannot be implemented through conventional methods. We present preliminary investigations of superconducting cavities made through a selective laser melting process, which compacts a granular powder via a high-power laser according to a digitally defined geometry. Initial work suggests that assuming a loss model and numerically optimizing a geometry to minimize dissipation results in modest improvements in device performance. Furthermore, a subset of titanium alloys, particularly, a titanium, aluminum, vanadium alloy (Ti - 6Al - 4V) exhibits properties indicative of a high kinetic inductance material. This work is supported by LDRD 16-SI-004.

  14. Coupling ultracold atoms to a superconducting coplanar waveguide resonator

    OpenAIRE

    Hattermann, H.; Bothner, D.; Ley, L. Y.; Ferdinand, B.; Wiedmaier, D.; Sárkány, L.; Kleiner, R.; Koelle, D.; Fortágh, J.

    2017-01-01

    We demonstrate coupling of magnetically trapped ultracold $^87$Rb ground state atoms to a coherently driven superconducting coplanar resonator on an integrated atom chip. We measure the microwave field strength in the cavity through observation of the AC shift of the hyperfine transition frequency when the cavity is driven off-resonance from the atomic transition. The measured shifts are used to reconstruct the field in the resonator, in close agreement with transmission measurements of the c...

  15. One-phase dual converter for two quadrant power control of superconducting magnets

    International Nuclear Information System (INIS)

    Ehsani, M.; Kustom, R.I.; Boom, R.W.

    1985-01-01

    This paper presents the results of theoretical and experimental development of a new dc-ac-dc converter for superconducting magnet power supplies. The basic operating principles of the circuit are described followed by a theoretical treatment of the dynamics and control of the system. The successful results of the first experimental operation and control of such a circuit are presented and discussed

  16. Effect of lead addition on the formation of superconducting phases in Bi-Sr-Ca-Cu-O ceramics

    International Nuclear Information System (INIS)

    Martinelli, A.E.

    1991-01-01

    Superconducting ceramics with starting composition Bi 2 - x Pb x Sr 2 Ca 2 Cu 3 O y (0,0 ≤ X ≤ 0,6) were prepared in order to investigate the effects of partial substitution of Pb for Bi and sintering time and atmosphere in the formation of superconducting phases. For all samples X-ray diffraction analyses were performed to estimate the amount of superconducting phases; superconductivity was analysed by dc electrical resistance and ac magnetic susceptibility measurements. The main results show that: a) the longer the sintering time (up to 168 h), the larger the volume fraction of superconducting phases with critical temperature (T c ) greater than the temperature of nitrogen liquefaction; b) by partially substituting Pb for Bi it is possible to restrain the formation of 2212 phase (T c = 80 K) and to enhance the amount of 2223 phase (T c = 105 K); C) a heat treatment under oxygen atmosphere before sintering enhances the formation of 2223 phase. (author)

  17. Accidental beam loss in superconducting accelerators: Simulations, consequences of accidents and protective measures

    International Nuclear Information System (INIS)

    Drozhdin, A.; Mokhov, N.; Parker, B.

    1994-02-01

    The consequences of an accidental beam loss in superconducting accelerators and colliders of the next generation range from the mundane to rather dramatic, i.e., from superconducting magnet quench, to overheating of critical components, to a total destruction of some units via explosion. Specific measures are required to minimize and eliminate such events as much as practical. In this paper we study such accidents taking the Superconducting Supercollider complex as an example. Particle tracking, beam loss and energy deposition calculations were done using the realistic machine simulation with the Monte-Carlo codes MARS 12 and STRUCT. Protective measures for minimizing the damaging effects of prefire and misfire of injection and extraction kicker magnets are proposed here

  18. Simulating the effect of SFCL on limiting the internal fault of synchronous machine

    International Nuclear Information System (INIS)

    Kheirizad, I; Varahram, M H; Jahed-Motlagh, M R; Rahnema, M; Mohammadi, A

    2008-01-01

    In this paper, we have modelled a synchronous generator with internal one phase to ground fault and then the performance of this machine with internal one phase to ground fault have been analyzed. The results show that if the faults occur in vicinity of machine's terminal, then we would have serious damages. To protect the machine from this kind of faults we have suggested integrating a SFCL (superconducting fault current limiter) into the machine's model. The results show that the fault currents in this case will reduce considerably without influencing the normal operation of the machine

  19. Report on achievements in fiscal 1999. Research and development of electric power storage using high-temperature super-conductive flywheels (research and development on manufacture of super-conductive magnetic bearings); 1999 nendo koon chodendo flywheel denryoku chozo kenkyu kaihatsu. Chodendo jiki jikuuke no seisaku no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-05-01

    Introduction of electric power storage equipment is sought, which will be discretely installed in power distribution substations. Therefore, elementary technologies were researched on 'manufacture of super-conductive magnetic bearings' intended for practical application of an electric power storage system of 10-MWh class using high-temperature super-conductive flywheels. Research and development has been performed on different kinds of super-conductive magnetic bearings which combine high-temperature super-conductive materials with permanent magnets. In order to measure the characteristics of the super-conductive magnetic bearings, measurements were executed on rotation loss, loading power and bearing constants. In the measurement of the rotation loss, a {phi} 180 axial type super-conductive magnetic bearing using an Sm-based superconductor ({phi} 180AxSMB2) was given various kinds of tests by using a rotation loss measuring and testing machine. The results were compared with those for the {phi} 180AxSMB1 using the YBCO-based superconductor and other SMBs. In the measurements for the other items, various items were measured on dynamic rotation properties of the {phi} 180AxSMB and {phi} 180RaSMB by using a static bearing constant testing machine. In discussing the loading power characteristics, the dynamic rotation properties of the {phi} 180RaSMB were measured, and the loading power characteristics were discussed on super-conductive magnetic bearings for medium size models and super-conductive magnetic bearings for large system FS. (NEDO)

  20. Machine Protection

    CERN Document Server

    Schmidt, R

    2014-01-01

    The protection of accelerator equipment is as old as accelerator technology and was for many years related to high-power equipment. Examples are the protection of powering equipment from overheating (magnets, power converters, high-current cables), of superconducting magnets from damage after a quench and of klystrons. The protection of equipment from beam accidents is more recent. It is related to the increasing beam power of high-power proton accelerators such as ISIS, SNS, ESS and the PSI cyclotron, to the emission of synchrotron light by electron–positron accelerators and FELs, and to the increase of energy stored in the beam (in particular for hadron colliders such as LHC). Designing a machine protection system requires an excellent understanding of accelerator physics and operation to anticipate possible failures that could lead to damage. Machine protection includes beam and equipment monitoring, a system to safely stop beam operation (e.g. dumping the beam or stopping the beam at low energy) and an ...

  1. High coherence plane breaking packaging for superconducting qubits

    Science.gov (United States)

    Bronn, Nicholas T.; Adiga, Vivekananda P.; Olivadese, Salvatore B.; Wu, Xian; Chow, Jerry M.; Pappas, David P.

    2018-04-01

    We demonstrate a pogo pin package for a superconducting quantum processor specifically designed with a nontrivial layout topology (e.g., a center qubit that cannot be accessed from the sides of the chip). Two experiments on two nominally identical superconducting quantum processors in pogo packages, which use commercially available parts and require modest machining tolerances, are performed at low temperature (10 mK) in a dilution refrigerator and both found to behave comparably to processors in standard planar packages with wirebonds where control and readout signals come in from the edges. Single- and two-qubit gate errors are also characterized via randomized benchmarking, exhibiting similar error rates as in standard packages, opening the possibility of integrating pogo pin packaging with extensible qubit architectures.

  2. Commutator dc machines used as mechanical capacitors in a series resonant ohmic-heating circuit simulation

    International Nuclear Information System (INIS)

    Thullen, P.; Weldon, D.M.

    1979-01-01

    Rotating electrical machines, and in particular commutator dc machines can serve as a high-power energy-source for testing large, pulsed magnets. This paper describes a pulsed power supply based on traction motors which will be used to test the LASL prototype 20-MJ superconducting tokamak induction coil

  3. Effect of point disorder on superconducting properties of ultrathin epitaxial NbN films

    International Nuclear Information System (INIS)

    Jesudasan, John; Bagwe, Vivas; Mondal, Mintu; Chand, Madhavi; Kamlapure, Anand; Pai, S.P.; Raychaudhuri, Pratap; Mishra, Archana

    2009-01-01

    We synthesized homogeneously disordered epitaxial NbN films on MgO(100) substrates using reactive dc magnetron sputtering. The disorder of the films is characterized by the Loffe-Regel parameter k F I. The superconducting properties are studied through transport, ac-susceptibility measurements and electron tunneling. The superconducting transition temperature is studied as a function of thickness for films of different disorder. In the case of the less disordered film, there is a smooth decrease in T c with decreasing thickness but for the more disordered film, the T c shows a sharp decrease to zero at a threshold thickness. The superconducting energy gap is studied via planar tunnel junctions. It is found that for the less disordered films, the temperature dependence of the gap follows the BCS variation but for the more disordered ones, there is a significant deviation from the BCS curve, and the gap remains finite at T c indicating that the superconducting transition is either governed by phase fluctuations or a first order phase transition. (author)

  4. Recent R and D status for 70 MW class superconducting generators in the Super-GM project

    International Nuclear Information System (INIS)

    Ageta, T.

    2000-01-01

    Three types of 70 MW class superconducting generators called model machines have been developed to establish basic technologies for a pilot machine. The series of on-site verification tests was completed in June 1999. The world's highest generator output (79 MW), the world's longest continuous operation (1500 hours) and other excellent results were obtained. The model machine was connected to a commercial power grid and fundamental data were collected for future utilization. It is expected that fundamental technologies on design and manufacture required for a 200 MW class pilot machine are established. (author)

  5. Superconductivity

    CERN Document Server

    Thomas, D B

    1974-01-01

    A short general review is presented of the progress made in applied superconductivity as a result of work performed in connection with the high-energy physics program in Europe. The phenomenon of superconductivity and properties of superconductors of Types I and II are outlined. The main body of the paper deals with the development of niobium-titanium superconducting magnets and of radio-frequency superconducting cavities and accelerating structures. Examples of applications in and for high-energy physics experiments are given, including the large superconducting magnet for the Big European Bubble Chamber, prototype synchrotron magnets for the Super Proton Synchrotron, superconducting d.c. beam line magnets, and superconducting RF cavities for use in various laboratories. (0 refs).

  6. Melt formed superconducting joint between superconducting tapes

    International Nuclear Information System (INIS)

    Benz, M.G.; Knudsen, B.A.; Rumaner, L.E.; Zaabala, R.J.

    1992-01-01

    This patent describes a superconducting joint between contiguous superconducting tapes having an inner laminate comprised of a parent-metal layer selected from the group niobium, tantalum, technetium, and vanadium, a superconductive intermetallic compound layer on the parent-metal layer, a reactive-metal layer that is capable of combining with the parent-metal and forming the superconductive intermetallic compound, the joint comprising: a continuous precipitate of the superconductive intermetallic compound fused to the tapes forming a continuous superconducting path between the tapes

  7. Thermal analysis of the cryocooled superconducting magnet for the liquid helium-free hybrid magnet

    International Nuclear Information System (INIS)

    Ishizuka, Masayuki; Hamajima, Takataro; Itou, Tomoyuki; Sakuraba, Junji; Nishijima, Gen; Awaji, Satoshi; Watanabe, Kazuo

    2010-01-01

    The liquid helium-free hybrid magnet, which consists of an outer large bore cryocooled superconducting magnet and an inner water-cooled resistive magnet, was developed for magneto-science in high fields. The characteristic features of the cryogen-free outsert superconducting magnet are described in detail in this paper. The superconducting magnet cooled by Gifford-McMahon cryocoolers, which has a 360 mm room temperature bore in diameter, was designed to generate high magnetic fields up to 10 T. The hybrid magnet has generated the magnetic field of 27.5 T by combining 8.5 T generation of the cryogen-free superconducting magnet with 19 T generation of the water-cooled resistive magnet. The superconducting magnet was composed of inner Nb 3 Sn coils and outer NbTi coils. In particular, inner Nb 3 Sn coils were wound using high-strength CuNi-NbTi/Nb 3 Sn wires in consideration of large hoop stress. Although the cryocooled outsert superconducting magnet achieved 9.5 T, we found that the outsert magnet has a thermal problem to generate the designed maximum field of 10 T in the hybrid magnet operation. This problem is associated with unexpected AC losses in Nb 3 Sn wires.

  8. Superconducting tunneling with the tunneling Hamiltonian. II. Subgap harmonic structure

    International Nuclear Information System (INIS)

    Arnold, G.B.

    1987-01-01

    The theory of superconducting tunneling without the tunneling Hamiltonian is extended to treat superconductor/insulator/superconductor junctions in which the transmission coefficient of the insulating barrier approaches unity. The solution for the current in such junctions is obtained by solving the problem of a particle hopping in a one-dimensional lattice of sites, with forward and reverse transfer integrals that depend on the site. The results are applied to the problem of subgap harmonic structure in superconducting tunneling. The time-dependent current at finite voltage through a junction exhibiting subgap structure is found to have terms that oscillate at all integer multiples of the Josephson frequency, n(2eV/h). The amplitudes of these new, and as yet unmeasured, ac current contributions as a function of voltage are predicted

  9. Preliminary magnet design for a superconducting separated sector cyclotron

    International Nuclear Information System (INIS)

    Bertrand, P.; Chabert, A.; Duval, M.; Ripouteau, F.

    1992-01-01

    This paper reports that in order to increase the energies available at GANIL, studies on a superconducting separated six straight sector cyclotron for heavy ions with energy up to 500 MeV/A (ions with Q/A = 0.5) have been performed. With a mean injection radius of 2.5 m and an extraction radius of 5 m, the maximum magnetic field on a sector has to be 5T. Each of the six sectors consists of two superconducting main coils (wound around the poles), room temperature iron pole pieces and a large yoke. Due to the broad ranges of energy and ion species, the required field laws are very different and for the most difficult operating point, the induction difference between the injection and ejection radii is about one Tesla. As a consequence, correcting coils have to provide a high field and one unusual point is that the machine will be operated with superconducting trim coils

  10. Machine Translation - A Gentle Introduction

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 7. Machine Translation - A Gentle Introduction. Durgesh D Rao. General Article Volume 3 Issue 7 July 1998 pp 61-70. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/003/07/0061-0070 ...

  11. Winding workshop for the ISR low beta Superconducting Quadrupole Prototype

    CERN Multimedia

    1975-01-01

    From right to left one sees the wire spool with its electro-magnetic brake to ensure a constant tension of the superconducting wire, a pulley with a wire length recording and the winding machine. In front on the table a finished coil. In the back the heavy clamping tool. See also 7510213X, 7510213X.

  12. Development of superconducting power devices in Europe

    International Nuclear Information System (INIS)

    Tixador, Pascal

    2010-01-01

    Europe celebrated last year (2008) the 100-year anniversary of the first liquefaction of helium by H. Kammerling Onnes in Leiden. It led to the discovery of superconductivity in 1911. Europe is still active in the development of superconducting (SC) devices. The discovery of high critical temperature materials in 1986, again in Europe, has opened a lot of opportunities for SC devices by broking the 4 K cryogenic bottleneck. Electric networks experience deep changes due to the emergence of dispersed generation (renewable among other) and to the advances in ICT (Information Communication Technologies). The networks of the future will be 'smart grids'. Superconductivity will offer 'smart' devices for these grids like FCL (Fault Current Limiter) or VLI (Very Low Inductance) cable and would certainly play an important part. Superconductivity also will participate to the required sustainable development by lowering the losses and enhancing the mass specific powers. Different SC projects in Europe will be presented (Cable, FCL, SMES, Flywheel and Electrical Machine) but the description is not exhaustive. Nexans has commercialized the first two FCLs without public funds in the European grid (UK and Germany). The Amsterdam HTS cable is an exciting challenge in term of losses for long SC cables. European companies (Nexans, Air Liquide, Siemens, Converteam, ...) are also very active for projects outside Europe (LIPA, DOE FCL, ...).

  13. Quench Detection and Protection for High Temperature Superconducting Transformers by Using the Active Power Method

    Science.gov (United States)

    Nanato, N.; Kobayashi, Y.

    AC high temperature superconducting (HTS) coils have been developed for transformers, motors and so on. Quench detection and protection system are essential for safety operations of the AC HTS facilities. The balance voltage method is universally used for the quench detection and protection, however especially for AC operations, the method has risks in terms of high voltage sparks. Because the method needs a voltage tap soldered to a midpoint of the coil winding and the AC HTS facilities generally operate at high voltages and therefore high voltage sparks may occur at the midpoint with no insulation. We have proposed the active power method for the quench detection and protection. The method requires no voltage tap on the midpoint of the coil winding and therefore it has in-built effectiveness for the AC HTS facilities. In this paper, we show that the method can detect the quench in an HTS transformer and moreover our proposed quench protection circuits which consist of thyristors are simple and useful for the AC HTS facilities.

  14. Direct visualization of the Campbell regime in superconducting stripes

    OpenAIRE

    Kramer, R. B. G.; Ataklti, G. W.; Moshchalkov, V. V.; Silhanek, Alejandro

    2010-01-01

    A combination of scanning Hall microscopy and scanning ac-susceptibility measurements in superconducting stripes (ribbons) of width w < 10 mu m was used to observe the dimensional phase transitions of the vortex lattice and its stability under alternating fields. At low dc magnetic fields applied perpendicularly to the plane of the stripes, vortices form a one-dimensional chain at the center of the stripes. Above a certain field H*(w), the vortex chain splits in two parallel rows displaced la...

  15. Reprint of “Performance analysis of a model-sized superconducting DC transmission system based VSC-HVDC transmission technologies using RTDS”

    International Nuclear Information System (INIS)

    Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun

    2013-01-01

    Highlights: ► A model-sized superconducting VSC-HVDC system was designed and fabricated. ► A real-time simulation using Real Time Digital Simulator has been performed. ► The AC loss characteristics of HTS DC power cable caused by harmonics were analyzed. ► The AC loss of the HTS DC power cable will be used as a parameter to design the cable cooling system. -- Abstract: The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test. In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail

  16. Reprint of “Performance analysis of a model-sized superconducting DC transmission system based VSC-HVDC transmission technologies using RTDS”

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, Minh-Chau, E-mail: thanchau7787@gmail.com [Changwon National University, 9 Sarim-Dong, Changwon 641-733 (Korea, Republic of); Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon [Changwon National University, 9 Sarim-Dong, Changwon 641-733 (Korea, Republic of); Yu, In-Keun, E-mail: yuik@changwon.ac.kr [Changwon National University, 9 Sarim-Dong, Changwon 641-733 (Korea, Republic of)

    2013-01-15

    Highlights: ► A model-sized superconducting VSC-HVDC system was designed and fabricated. ► A real-time simulation using Real Time Digital Simulator has been performed. ► The AC loss characteristics of HTS DC power cable caused by harmonics were analyzed. ► The AC loss of the HTS DC power cable will be used as a parameter to design the cable cooling system. -- Abstract: The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test. In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail.

  17. Offline detection of broken rotor bars in AC induction motors

    Science.gov (United States)

    Powers, Craig Stephen

    ABSTRACT. OFFLINE DETECTION OF BROKEN ROTOR BARS IN AC INDUCTION MOTORS. The detection of the broken rotor bar defect in medium- and large-sized AC induction machines is currently one of the most difficult tasks for the motor condition and monitoring industry. If a broken rotor bar defect goes undetected, it can cause a catastrophic failure of an expensive machine. If a broken rotor bar defect is falsely determined, it wastes time and money to physically tear down and inspect the machine only to find an incorrect diagnosis. Previous work in 2009 at Baker/SKF-USA in collaboration with the Korea University has developed a prototype instrument that has been highly successful in correctly detecting the broken rotor bar defect in ACIMs where other methods have failed. Dr. Sang Bin and his students at the Korea University have been using this prototype instrument to help the industry save money in the successful detection of the BRB defect. A review of the current state of motor conditioning and monitoring technology for detecting the broken rotor bar defect in ACIMs shows improved detection of this fault is still relevant. An analysis of previous work in the creation of this prototype instrument leads into the refactoring of the software and hardware into something more deployable, cost effective and commercially viable.

  18. Compensation methods applied in current control schemes for large AC drive systems

    DEFF Research Database (Denmark)

    Rus, D. C.; Preda, N. S.; Teodorescu, Remus

    2012-01-01

    The paper deals with modified PI current control structures for large AC drive systems which use surface mounted permanent magnet synchronous machines or squirrel-cage induction motors supplied with voltage source inverters. In order to reduce the power losses caused by high frequency switching...

  19. Numerical analysis of ac loss in bifilar stacks and coils of ion beam assisted deposition YBCO coated conductors

    International Nuclear Information System (INIS)

    Nguyen, Doan N.; Ashworth, Stephen P.; Willis, Jeffrey O.

    2009-01-01

    In this paper we present a finite element model using the commercial COMSOL software package for calculating the ac loss in bifilar stacks of high temperature superconducting tape. In the model, the current-voltage relationship characterizing the superconducting properties is assumed to follow a power law. The calculations were performed for infinite bifilar stacks with different values of layer-to-layer separation D. With appropriate settings for the boundary conditions, the numerical results agree well with the analytical data obtained from a recently proposed model [J. R. Clem, Phys. Rev. B 77, 134506 (2008)]. The numerical approach was also used to investigate the end effects in a bifilar stack to answer the following question: how many layers away from the end of a stack are required before the environment of a given layer is identical to that in an infinite stack? We find that the answer to this question depends strongly on the value of D. Based on this study, a model for calculating the ac loss in bifilar noninductively wound coils with a finite number of turns is proposed

  20. Design study of high-temperature superconducting generators for wind power systems

    Energy Technology Data Exchange (ETDEWEB)

    Maki, N [Technova Inc. 13th Fl. Imperial Hotel Tower, 1-chome, Chiyoda-ku, Tokyo 100-0011 (Japan)], E-mail: naokmaki@technova.co.jp

    2008-02-15

    Design study on high-temperature superconducting machines (HTSM) for wind power systems was carried out using specially developed design program. Outline of the design program was shown and the influence of machine parameters such as pole number, rotor outer diameter and synchronous reactance on the machine performance was clarified. Three kinds of generator structure are considered for wind power systems and the HTSM operated under highly magnetic saturated conditions with conventional rotor and stator has better performance than the other types of HTSM. Furthermore, conceptual structure of 8 MW, 20 pole HTSM adopting salient-pole rotor as in the case of water turbine generators and race-truck shaped HTS field windings like Japanese Maglev was shown.

  1. Design study of high-temperature superconducting generators for wind power systems

    International Nuclear Information System (INIS)

    Maki, N

    2008-01-01

    Design study on high-temperature superconducting machines (HTSM) for wind power systems was carried out using specially developed design program. Outline of the design program was shown and the influence of machine parameters such as pole number, rotor outer diameter and synchronous reactance on the machine performance was clarified. Three kinds of generator structure are considered for wind power systems and the HTSM operated under highly magnetic saturated conditions with conventional rotor and stator has better performance than the other types of HTSM. Furthermore, conceptual structure of 8 MW, 20 pole HTSM adopting salient-pole rotor as in the case of water turbine generators and race-truck shaped HTS field windings like Japanese Maglev was shown

  2. Concept of a Machine Protection System for the High-Energy LHC

    CERN Document Server

    Raginel, Vivien; Wollmann, Daniel

    2018-01-01

    The High-Energy LHC (HE-LHC) is setting new precedents in stored energy in both, the superconducting magnet system (∼ 20 GJ) and the beams (1.34 GJ) as compared to LHC and the LHC upgrade to increase the luminosity (HL-LHC). Therefore, the requirements and performance of the existing machine protection systems have to be reviewed and adapted to the new HE-LHC beam parameters, failure cases and machine availability requirements.

  3. Electromagnetic force analysis on the stator and rotor windings of a superconducting generator

    International Nuclear Information System (INIS)

    Colovini, L.; Martinelli, G.; Morini, A.

    1985-01-01

    The determination of values and distribution of the forces acting on the components of a superconducting generator is important when designing the machine, particularly in the choice of materials. The paper analyses the electromagnetic forces acting on the field and armature windings; for this purpose, with reference to the preliminary design of a two-pole 300 MVA superconducting generator, a two-dimensional analytical method set up by the authors is utilized to calculate the forces on the windings under steady state operation and results are compared with those obtained by means of a numerical method

  4. Superconductivity

    CERN Document Server

    Poole, Charles P; Farach, Horacio A

    1995-01-01

    Superconductivity covers the nature of the phenomenon of superconductivity. The book discusses the fundamental principles of superconductivity; the essential features of the superconducting state-the phenomena of zero resistance and perfect diamagnetism; and the properties of the various classes of superconductors, including the organics, the buckministerfullerenes, and the precursors to the cuprates. The text also describes superconductivity from the viewpoint of thermodynamics and provides expressions for the free energy; the Ginzburg-Landau and BCS theories; and the structures of the high

  5. AC over-current test results of YBCO conductor for YBCO power transformer with fault current limiting function

    International Nuclear Information System (INIS)

    Tomioka, A.; Otonari, T.; Ogata, T.; Iwakuma, M.; Okamoto, H.; Hayashi, H.; Iijima, Y.; Saito, T.; Gosho, Y.; Tanabe, K.; Izumi, T.; Shiohara, Y.

    2011-01-01

    The single-layer coils with a diameter of 250 mm and 12 turns were manufactured with YBCO tapes with a CuNi- or Cu-Tape. The AC over-current tests were carried out in subcooled liquid nitrogen at 66 K and 74 K to develop power transformers with current limiting function. The AC over-current was two to seven times larger than the I c of conductor and it was reduced to the same level of I c . The I c of model coils did not degrade. The test results showed the possibility of YBCO superconducting transformers with current limiting function. We are developing elemental technology for 66 kV/6.9 kV 20 MVA-class YBCO power transformer. The YBCO transformer is considered to have a possibility to stabilize the power system by improving function of fault current limiting. Current limiting behavior functions over critical current flows. There is a possibility that superconducting characteristic may be damaged due to increase in temperature of YBCO tapes. Therefore, we have taken a measure to combine YBCO tape with CuNi tape or Cu Tape. We manufactured model coils using these conductors and conducted the AC over-current tests. The test current was two to seven times larger than the I c of conductor and it was damped with time from its maximum value according to the generation of conductor resistance. We verified the effectiveness of current limiting characteristics. In these tests, the I c of model coil did not degrade. We consider this conductor to be able to withstand AC over-current with the function of current limiting.

  6. CAS CERN Accelerator School superconductivity in particle accelerators

    International Nuclear Information System (INIS)

    Turner, S.

    1989-01-01

    One of the objectives of the CERN Accelerator School is to run courses on specialised topics in the particle accelerator field. The present volume contains the proceedings of one such course, this time organized in conjunction with the Deutsches Elektronen Synchrotron (DESY) on the subject of superconductivity in particle accelerators. This course reflects the very considerable progress made over the last few years in the use of the technology for the magnet and radio-frequency systems of many large and small accelerators already in use or nearing completion, while also taking account of the development work now going on for future machines. The lectures cover the theory of superconductivity, cryogenics and accelerator magnets and cavities, while the seminars include superfluidity, superconductors, special magnets and the prospects for high-temperature superconductors. (orig.)

  7. Filter Influence on Rotor Losses in Coreless Axial Flux Permanent Magnet Machines

    Directory of Open Access Journals (Sweden)

    SANTIAGO, J.

    2013-02-01

    Full Text Available This paper investigates the eddy current losses induced in the rotor of coreless Axial-Flux machines. The calculation of eddy currents in the magnets requires the simulation of the inverter and the filter to obtain the harmonic content of the stator currents and FEM analysis of the magnets in the rotor. Due to the low inductance in coreless machines, the induced eddy current losses in the rotor remain lower than in traditional slotted machines. If only machine losses are considered, filters in DC/AC converters are not required in machines with wide airgaps as time harmonic losses in the rotor are very low.The harmonic content both from simulations and experimental results of a DC/AC converter are used to calculate the eddy currents in the rotor magnets. The properties of coreless machine topologies are investigated and some simplifications are proposed for time efficient 3D-FEM analysis. The time varying magnetic field can be considered constant over the magnets when the pole is divided in several magnets.The simplified FEM method to calculate eddy current losses is applicable to coreless machines with poles split into several magnets, although the conclusions are applicable to all coreless and slotless motors and generators.

  8. Superconducting Electric Machine with Permanent Magnets and Bulk HTS Elements

    Science.gov (United States)

    Levin, A. V.; Vasich, P. S.; Dezhin, D. S.; Kovalev, L. K.; Kovalev, K. L.; Poltavets, V. N.; Penkin, V. T.

    Theoretical methods of calculating of two-dimensional magnetic fields, inductive parameters and output characteristics of the new type of high-temperature superconducting (HTS) synchronous motors with a composite rotor are presented. The composite rotor has the structure containing HTS flat elements, permanent magnets and ferromagnetic materials. The developed calculation model takes into account the concentrations and physical properties of these rotor elements. The simulation results of experimental HTS motor with a composite rotor are presented. The application of new type of HTS motor in different constructions of industrial high dynamic drivers is discussed.

  9. Control System of the Superconducting 63-Pole 2-Tesla Wiggler for Canadian Light Source

    International Nuclear Information System (INIS)

    Kuper, E.A.; Mezentsev, N.A.; Miginsky, E.G.; Repkov, V.V.; Tsukanov, V.M.

    2006-01-01

    A control system of the superconducting 63-pole wiggler fabricated at the Institute of Nuclear Physics in Novosibirsk (BINP) for Synchrotron Radiation Center in Canada (CLS) is described. Specific electronics and software which provide continuos monitoring of all the superconducting wiggler parameters as well as full control and monitoring of power suppliers and cryogenics machines, have been designed. The control system is VME-based. A client/server architecture of the software allowed us to integrate easily this system into the CLS distributed control system

  10. The Bearingless Electrical Machine

    Science.gov (United States)

    Bichsel, J.

    1992-01-01

    Electromagnetic bearings allow the suspension of solids. For rotary applications, the most important physical effect is the force of a magnetic circuit to a high permeable armature, called the MAXWELL force. Contrary to the commonly used MAXWELL bearings, the bearingless electrical machine will take advantage of the reaction force of a conductor carrying a current in a magnetic field. This kind of force, called Lorentz force, generates the torque in direct current, asynchronous and synchronous machines. The magnetic field, which already exists in electrical machines and helps to build up the torque, can also be used for the suspension of the rotor. Besides the normal winding of the stator, a special winding was added, which generates forces for levitation. So a radial bearing, which is integrated directly in the active part of the machine, and the motor use the laminated core simultaneously. The winding was constructed for the levitating forces in a special way so that commercially available standard ac inverters for drives can be used. Besides wholly magnetic suspended machines, there is a wide range of applications for normal drives with ball bearings. Resonances of the rotor, especially critical speeds, can be damped actively.

  11. Inhomogeneities and superconductivity in poly-phase Fe-Se-Te systems

    Science.gov (United States)

    Hartwig, S.; Schäfer, N.; Schulze, M.; Landsgesell, S.; Abou-Ras, D.; Blum, Ch. G. F.; Wurmehl, S.; Sokolowski, A.; Büchner, B.; Prokeš, K.

    2018-02-01

    The impact of synthesis conditions, post-preparation heating procedure, aging and influence of pressure on the superconducting properties of FeSe0.4Te0.6 crystals is reported. Two FeSe0.4Te0.6 single crystals were used in the study, prepared from stoichiometric melt but cooled down with very different cooling rates, and investigated using magnetic bulk and electrical-resistivity methods. The fast-cooled crystal contains large inclusions of Fe3Se2.1Te1.8 and exhibits bulk superconductivity in its as-prepared state, while the other is homogeneous and shows only traces of superconductivity. AC susceptibility measurements under hydrostatic pressure show that the superconducting transition temperature of the inhomogeneous crystal increases from 12.3 K at ambient pressure to Tsc = 17.9 K at 9 kbar. On the other hand, neither pressure nor mechanically-induced stress is sufficient to induce superconductivity in the homogeneous crystal. However, an additional heat treatment at 673 K followed by fast cooling down and/or long-term aging at ambient conditions leads to the appearance of bulk superconductivity also in the latter sample. This sample remains homogeneous on a scale down to few μm but shows an additional magnetic phase transition around 130 K suggesting that it must be inhomogeneous. For comparison also Fe3Se2.1Te1.8 polycrystals have been prepared and their magnetic properties have been studied. It appears that this phase is not superconducting by itself. It is concluded that nano-scale inhomogeneities that appear in the FeSexTe1-x system due to a spinodal decomposition in the solid state are necessary for bulk superconductivity, possibly due to minor changes in the crystal structure and microstructure. Macroscopic inclusions quenched by fast cooling from high temperatures lead obviously to strain and hence variations in the lattice constants, an effect that is further supported by application of pressure/stress.

  12. Application of alternating current for dimensionally electrochemical machining

    International Nuclear Information System (INIS)

    Kacheev, M.K.; Kovalev, L.M.

    1978-01-01

    The results of comparative experimental investigations in dimensionally electrochemical machining of 1Kh18N9T steel using alternating and direct currents are presented. The effect of the electrolyte rate in the inter-electrode clearance, electrode voltage and oscillation amplitude of the electrode-tool on the metal output from the electrodes and the relief of the machined surface is studied. It is shown that the a.c. electrochemical machining permits to achieve the greater dimensional accuracy than the d.c. machining when choosing the proper voltage and electrolyte composition. It is connected with the fact that the prevailing part of the metal output is obtained in the impulse-asymmetrical regime when the inter-electrode clearance is minimum

  13. Modelling, Construction, and Testing of a Simple HTS Machine Demonstrator

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Abrahamsen, Asger Bech

    2011-01-01

    This paper describes the construction, modeling and experimental testing of a high temperature superconducting (HTS) machine prototype employing second generation (2G) coated conductors in the field winding. The prototype is constructed in a simple way, with the purpose of having an inexpensive way...... of validating finite element (FE) simulations and gaining a better understanding of HTS machines. 3D FE simulations of the machine are compared to measured current vs. voltage (IV) curves for the tape on its own. It is validated that this method can be used to predict the critical current of the HTS tape...... installed in the machine. The measured torque as a function of rotor position is also reproduced by the 3D FE model....

  14. Performance of the Protection System for Superconducting Circuits during LHC Operation

    OpenAIRE

    Denz, R; Charifoulline, Z; Dahlerup-Petersen, K; Schmidt, R; Siemko, A; Steckert, J

    2011-01-01

    The protection system for superconducting magnets and bus-bars is an essential part of the LHC machine protection and ensures the integrity of substantial elements of the accelerator. Due to the large amount of hardwired and software interlock channels the dependability of the system is a critical parameter for the successful operation of the LHC.

  15. Filament bundle location influence on coupling losses in superconducting composites

    International Nuclear Information System (INIS)

    Ito, Daisuke; Koizumi, Misao; Hamajima, Takataro; Nakane, Fumoto.

    1983-01-01

    The ac losses in multifilamentary superconducting composites with different superconducting filament bundle positions have been measured using the magnetization method in order to reveal the relation between filament bundle position and coupling losses. Loss components depending on dB/dt in a mixed matrix superconducting composite, whose filament bundle is located in a central region surrounded by an outer stabilizing copper sheath, has been compared with another superconducting composite whose stabilizing copper is located in a central region surrounded by an outer filament bundle. In both conductors, key parameters, such as filament twistpitch, wire diameter and amount of copper stabilizer, were almost the same. Applied magnetic field is 2 Tesla with 0.05-2 Tesla/sec field change rate. Experimental results indicate that coupling losses between filaments in the composite with the filament bundle located in the central region is smaller than the composite with the filament bundle located in the outer region. A similar conclusion was reached theoretically by B. Truck. Coupling loss values obtained by the experiment show good agreement with calculated values with the equations proposed by B. Truck. It is also pointed out that a copper stabilizer, divided by the CuNi barrier into small regions, like a honeycomb, causes anomalous increasing in the copper resistivity due to Ni diffusion during heat treatment. (author)

  16. Superconductivity

    International Nuclear Information System (INIS)

    Taylor, A.W.B.; Noakes, G.R.

    1981-01-01

    This book is an elementray introduction into superconductivity. The topics are the superconducting state, the magnetic properties of superconductors, type I superconductors, type II superconductors and a chapter on the superconductivity theory. (WL)

  17. Superconductivity

    International Nuclear Information System (INIS)

    Onnes, H.K.

    1988-01-01

    The author traces the development of superconductivity from 1911 to 1986. Some of the areas he explores are the Meissner Effect, theoretical developments, experimental developments, engineering achievements, research in superconducting magnets, and research in superconducting electronics. The article also mentions applications shown to be technically feasible, but not yet commercialized. High-temperature superconductivity may provide enough leverage to bring these applications to the marketplace

  18. Superconductivity

    International Nuclear Information System (INIS)

    Andersen, N.H.; Mortensen, K.

    1988-12-01

    This report contains lecture notes of the basic lectures presented at the 1st Topsoee Summer School on Superconductivity held at Risoe National Laboratory, June 20-24, 1988. The following lecture notes are included: L.M. Falicov: 'Superconductivity: Phenomenology', A. Bohr and O. Ulfbeck: 'Quantal structure of superconductivity. Gauge angle', G. Aeppli: 'Muons, neutrons and superconductivity', N.F. Pedersen: 'The Josephson junction', C. Michel: 'Physicochemistry of high-T c superconductors', C. Laverick and J.K. Hulm: 'Manufacturing and application of superconducting wires', J. Clarke: 'SQUID concepts and systems'. (orig.) With 10 tabs., 128 figs., 219 refs

  19. Gram staining with an automatic machine.

    Science.gov (United States)

    Felek, S; Arslan, A

    1999-01-01

    This study was undertaken to develop a new Gram-staining machine controlled by a micro-controller and to investigate the quality of slides that were stained in the machine. The machine was designed and produced by the authors. It uses standard 220 V AC. Staining, washing, and drying periods are controlled by a timer built in the micro-controller. A software was made that contains a certain algorithm and time intervals for the staining mode. One-hundred and forty smears were prepared from Escherichia coli, Staphylococcus aureus, Neisseria sp., blood culture, trypticase soy broth, direct pus and sputum smears for comparison studies. Half of the slides in each group were stained with the machine, the other half by hand and then examined by four different microbiologists. Machine-stained slides had a higher clarity and less debris than the hand-stained slides (p stained slides, some Gram-positive organisms showed poor Gram-positive staining features (p Gram staining with the automatic machine increases the staining quality and helps to decrease the work load in a busy diagnostic laboratory.

  20. A 3D printed superconducting aluminium microwave cavity

    Energy Technology Data Exchange (ETDEWEB)

    Creedon, Daniel L. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Goryachev, Maxim; Kostylev, Nikita; Tobar, Michael E., E-mail: michael.tobar@uwa.edu.au [ARC Centre of Excellence for Engineered Quantum Systems, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Sercombe, Timothy B. [School of Mechanical and Chemical Engineering, University of Western Australia, 35 Stirling Highway, Crawley 6009 (Australia)

    2016-07-18

    3D printing of plastics, ceramics, and metals has existed for several decades and has revolutionized many areas of manufacturing and science. Printing of metals, in particular, has found a number of applications in fields as diverse as customized medical implants, jet engine bearings, and rapid prototyping in the automotive industry. Although many techniques are used for 3D printing metals, they commonly rely on computer controlled melting or sintering of a metal alloy powder using a laser or electron beam. The mechanical properties of parts produced in such a way have been well studied, but little attention has been paid to their electrical properties. Here we show that a microwave cavity (resonant frequencies 9.9 and 11.2 GHz) 3D printed using an Al-12Si alloy exhibits superconductivity when cooled below the critical temperature of aluminium (1.2 K), with a performance comparable with the common 6061 alloy of aluminium. Superconducting cavities find application in numerous areas of physics, from particle accelerators to cavity quantum electrodynamics experiments. The result is achieved even with a very large concentration of non-superconducting silicon in the alloy of 12.18%, compared with Al-6061, which has between 0.4% and 0.8%. Our results may pave the way for the possibility of 3D printing superconducting cavity configurations that are otherwise impossible to machine.

  1. A 3D printed superconducting aluminium microwave cavity

    International Nuclear Information System (INIS)

    Creedon, Daniel L.; Goryachev, Maxim; Kostylev, Nikita; Tobar, Michael E.; Sercombe, Timothy B.

    2016-01-01

    3D printing of plastics, ceramics, and metals has existed for several decades and has revolutionized many areas of manufacturing and science. Printing of metals, in particular, has found a number of applications in fields as diverse as customized medical implants, jet engine bearings, and rapid prototyping in the automotive industry. Although many techniques are used for 3D printing metals, they commonly rely on computer controlled melting or sintering of a metal alloy powder using a laser or electron beam. The mechanical properties of parts produced in such a way have been well studied, but little attention has been paid to their electrical properties. Here we show that a microwave cavity (resonant frequencies 9.9 and 11.2 GHz) 3D printed using an Al-12Si alloy exhibits superconductivity when cooled below the critical temperature of aluminium (1.2 K), with a performance comparable with the common 6061 alloy of aluminium. Superconducting cavities find application in numerous areas of physics, from particle accelerators to cavity quantum electrodynamics experiments. The result is achieved even with a very large concentration of non-superconducting silicon in the alloy of 12.18%, compared with Al-6061, which has between 0.4% and 0.8%. Our results may pave the way for the possibility of 3D printing superconducting cavity configurations that are otherwise impossible to machine.

  2. A 3D printed superconducting aluminium microwave cavity

    Science.gov (United States)

    Creedon, Daniel L.; Goryachev, Maxim; Kostylev, Nikita; Sercombe, Timothy B.; Tobar, Michael E.

    2016-07-01

    3D printing of plastics, ceramics, and metals has existed for several decades and has revolutionized many areas of manufacturing and science. Printing of metals, in particular, has found a number of applications in fields as diverse as customized medical implants, jet engine bearings, and rapid prototyping in the automotive industry. Although many techniques are used for 3D printing metals, they commonly rely on computer controlled melting or sintering of a metal alloy powder using a laser or electron beam. The mechanical properties of parts produced in such a way have been well studied, but little attention has been paid to their electrical properties. Here we show that a microwave cavity (resonant frequencies 9.9 and 11.2 GHz) 3D printed using an Al-12Si alloy exhibits superconductivity when cooled below the critical temperature of aluminium (1.2 K), with a performance comparable with the common 6061 alloy of aluminium. Superconducting cavities find application in numerous areas of physics, from particle accelerators to cavity quantum electrodynamics experiments. The result is achieved even with a very large concentration of non-superconducting silicon in the alloy of 12.18%, compared with Al-6061, which has between 0.4% and 0.8%. Our results may pave the way for the possibility of 3D printing superconducting cavity configurations that are otherwise impossible to machine.

  3. Application of an analytical method for the field calculation in superconducting magnets

    International Nuclear Information System (INIS)

    Martinelli, G.; Morini, A.

    1983-01-01

    Superconducting magnets are taking on ever-growing importance due to their increasing prospects of utilization in electrical machines, nuclear fusion, MHD conversion and high-energy physics. These magnets are generally composed of cylindrical or saddle coils, while a ferromagnetic shield is generally situated outside them. This paper uses an analytical method for calculating the magnetic field at every point in a superconducting magnet composed of cylindrical or saddle coils. The method takes into account the real lengths and finite thickness of the coils as well as their radial and axial ferromagnetic shields, if present. The values and distribution of the flux density for some superconducting magnets of high dimensions and high magnetic field, composed of cylindrical or saddle coils, are also given. The results obtained with analytical method are compared with those obtained using numerical methods

  4. Capacitor energy needed to induce transitions from the superconducting to the normal state

    International Nuclear Information System (INIS)

    Eberhard, P.H.; Ross, R.R.

    1985-08-01

    The purpose of this paper is to describe a technique to turn a long length of superconducting wire normal by dumping a charged capacitor into it and justify some formulae needed in the design. The physical phenomenon is described. A formula for the energy to be stored in the capacitor is given. There are circumstances where the dc in an electrical circuit containing superconducting elements has to be turned off quickly and where the most convenient way to switch the current off is to turn a large portion or all of the superconducting wire normal. Such was the case of the Time Projection Chamber (TPC) superconducting magnet as soon as a quench was detected. The technique used was the discharge of a capacitor into the coil center tap. It turned the magnet winding normal in ten milliseconds or so and provided an adequate quench protection. The technique of discharging a capacitor into a superconducting wire should have many other applications whenever a substantial resistance in a superconducting circuit has to be generated in that kind of time scale. The process involves generating a pulse of large currents in some part of the circuit and heating the wire up by ac losses until the value of the wire critical current is smaller than the dc current. Use of low inductance connections to the circuit is necessary. Then the dc gets turned off due to the resistance of the wire as in a magnet quench

  5. Superconductivity in the U(Th)-Y-Ba-Cu-O systems

    International Nuclear Information System (INIS)

    Qin Qizong; He Adi; Jia Weijie; Ma Lidun; Cheng Huansheng; Hua Zhongyi

    1989-01-01

    High T c superconductivity has been observed both resistively and magnetically in the new U(Th)-Y-Ba-Cu-O systems. The zero resistance temperature of the three samples with nominal composition of U 0.1 Y 1.1 Ba 0.8 Cu O 4-z , U 0.15 Y 1.05 Ba 0.8 Cu 4-z and Th 0.3 Y 0.8 Ba 0.8 Cu 4-z is 87K, 79K and 74K, respectively. The result of ac magnetic susceptibility measurement implies that the superconducting state is realized in the U-doped samples below 90K. The stoichimetry of the U-Y-Ba-Cu O superconductors has the aid of Rutherford backscattering and nuclear reaction 16 O(d, p) 17 O. The analytical results show that the 'real composition' of somples may be different from that of the nomial composition. The X ray diffraction analysis of the U-Y-Ba-Cu-O system shows that none of the peaks can be fitted to the uranium oxides and the other raw materiale structure, and its pattern may be attributed to new multiple phases with structure different from the known singlephase superconducting oxides

  6. Superconducting 7 T Wave Length Shifter for BESSY-II

    CERN Document Server

    Borovikov, V M; Fedurin, M G; Repkov, V V; Karpov, G V; Kulipanov, G N; Kuzin, M V; Mezentsev, N A; Shkaruba, V A; Krämer, Dietrich; Richter, D

    2001-01-01

    A superconducting 3-pole Wave Length Shifter (WLS) with a maximum field of 7 T was fabricated and tested by BINP in collaboration with BESSY-II. The radiation point is fixed in the center of WLS at any field level by using two correctors. The magnetic field is stabilized with an accuracy of 10 sup - sup 4 at 7 T by a feedback system based on NMR probes and magnetic flux pumps. Persistent current operation mode is enabled by using superconducting persistent keys. The magnetic field homogeneity of 10 sup - sup 4 at 7 T is obtained as a result of shimming in the aperture of the magnet. A protection system based on cold diodes and dump resistors prevents the destruction of superconducting coils during the quench. Two screens with temperatures of 20 and 60 K cooled by cooling machine, two recondensers, HTSC current leads and cevlar suspensions of helium volume are used to decrease liquid helium consumption. The main features and operating mode of the WLS are described.

  7. Theory of superconductivity

    International Nuclear Information System (INIS)

    Crisan, M.

    1988-01-01

    This book discusses the most important aspects of the theory. The phenomenological model is followed by the microscopic theory of superconductivity, in which modern formalism of the many-body theory is used to treat most important problems such as superconducting alloys, coexistence of superconductivity with the magnetic order, and superconductivity in quasi-one-dimensional systems. It concludes with a discussion on models for exotic and high temperature superconductivity. Its main aim is to review, as complete as possible, the theory of superconductivity from classical models and methods up to the 1987 results on high temperature superconductivity. Contents: Phenomenological Theory of Superconductivity; Microscopic Theory of Superconductivity; Theory of Superconducting Alloys; Superconductors in a Magnetic Field; Superconductivity and Magnetic Order; Superconductivity in Quasi-One-Dimensional Systems; and Non-Conventional Superconductivity

  8. Applied superconductivity

    CERN Document Server

    Newhouse, Vernon L

    1975-01-01

    Applied Superconductivity, Volume II, is part of a two-volume series on applied superconductivity. The first volume dealt with electronic applications and radiation detection, and contains a chapter on liquid helium refrigeration. The present volume discusses magnets, electromechanical applications, accelerators, and microwave and rf devices. The book opens with a chapter on high-field superconducting magnets, covering applications and magnet design. Subsequent chapters discuss superconductive machinery such as superconductive bearings and motors; rf superconducting devices; and future prospec

  9. Effects of an electromagnetic shield and armature teeth on the short-circuit performance of a direct drive superconducting generator for 10 MW wind turbines

    DEFF Research Database (Denmark)

    Liu, Dong; Polinder, Henk; Abrahamsen, Asger Bech

    2015-01-01

    reactance. An electromagnetic (EM) shield between the rotor and the stator as well as iron or non-magnetic composite (NMC) armature teeth affects the sub-transient reactance of a superconducting machine so that they play a role in the short-circuit performance of a superconducting wind generator. This paper...

  10. Superconducting properties of Zr1+xNi2-xGa and Zr1-xNi2+xGa Heusler compounds

    Directory of Open Access Journals (Sweden)

    Saad Alzahrani

    2017-05-01

    Full Text Available The superconducting properties of a series of Zr1+xNi2-xGa and Zr1-xNi2+xGa compounds have been investigated by x-ray diffraction, electrical resistivity, dc magnetization, and ac susceptibility measurements. While the parent compound, ZrNi2Ga, exhibited the cubic L21 Heusler structure, multiple non-cubic structures formed in the Zr and Ni rich doped materials. For x ≤ 0.3, all Zr1-xNi2+xGa compounds demonstrated superconducting behavior, but no superconductivity was observed in the Zr1+xNi2-xGa alloys for x > 0.2. The magnetization data revealed that all materials in both Zr1+xNi2-xGa and Zr1-xNi2+xGa series exhibited type-II superconductivity. With increasing doping concentration x, the paramagnetic ordering were enhanced in both systems while the superconducting properties were found to weaken. The observations are discussed considering the structural disorders in the systems.

  11. AC magnetization loss characteristics of HTS coated-conductors with magnetic substrates

    International Nuclear Information System (INIS)

    Tsukamoto, O.; Liu, M.; Odaka, S.; Miyagi, D.; Ohmatsu, K.

    2007-01-01

    AC magnetization loss characteristics of an HTS coated tape conductor with magnetic substrate subjected to an external AC magnetic field were investigated. The external magnetic field was perpendicular or parallel to the wide face of the tape conductor. Magnetization losses in the conductor and in the magnetic substrate itself without the superconductor layer, were measured by electric and calorimetric methods. The influence of the magnetic property of the substrate was strongly dependent on the direction of the external magnetic field. When the external magnetic field was perpendicular, magnetic property of the substrate did not affect the magnetization loss characteristics. This result suggests that the magnetization losses can be reduced by subdivisions of the superconducting layers even in the case of magnetic substrate conductors. When the external magnetic field was parallel, the magnetization losses were dominated by the losses in the magnetic substrate. Therefore, to reduce the magnetization losses in this case, reduction of magnetization losses in the substrate is necessary

  12. Characteristic Analysis of DC Electric Railway Systems with Superconducting Power Cables Connecting Power Substations

    Science.gov (United States)

    Ohsaki, H.; Matsushita, N.; Koseki, T.; Tomita, M.

    2014-05-01

    The application of superconducting power cables to DC electric railway systems has been studied. It could leads to an effective use of regenerative brake, improved energy efficiency, effective load sharing among the substations, etc. In this study, an electric circuit model of a DC feeding system is built and numerical simulation is carried out using MATLAB-Simulink software. A modified electric circuit model with an AC power grid connection taken into account is also created to simulate the influence of the grid connection. The analyses have proved that a certain amount of energy can be conserved by introducing superconducting cables, and that electric load distribution and concentration among the substations depend on the substation output voltage distribution.

  13. Characteristic analysis of DC electric railway systems with superconducting power cables connecting power substations

    International Nuclear Information System (INIS)

    Ohsaki, H; Matsushita, N; Koseki, T; Tomita, M

    2014-01-01

    The application of superconducting power cables to DC electric railway systems has been studied. It could leads to an effective use of regenerative brake, improved energy efficiency, effective load sharing among the substations, etc. In this study, an electric circuit model of a DC feeding system is built and numerical simulation is carried out using MATLAB-Simulink software. A modified electric circuit model with an AC power grid connection taken into account is also created to simulate the influence of the grid connection. The analyses have proved that a certain amount of energy can be conserved by introducing superconducting cables, and that electric load distribution and concentration among the substations depend on the substation output voltage distribution.

  14. The interplay of magnetic order and superconductivity in GdxY1-xNi2B2C

    International Nuclear Information System (INIS)

    Drzazga, Z.; Fuchs, G.; Handstein, A.; Nenkov, K.; Mueller, K.-H.

    2003-01-01

    Resistivity, ac susceptibility and magnetization measurements are reported for polycrystalline samples of the Gd x Y 1-x Ni 2 B 2 C series as a function of temperature and magnetic field. The magnetic Gd impurities cause an almost linear decrease of the superconducting transition temperature T c with increasing Gd content in the range of x c have been observed. The effect of the 4f local moments manifests in a complete suppression of superconductivity for x≥0.3 and in antiferromagnetic ordering for x>0.3. In zero applied magnetic field, a distinct concentration region around x∼0.3 has been revealed separating superconductivity and antiferromagneting ordering. A metamagnetic transition has been observed in the compound with x=0.5 at a magnetic field of 0.8 T

  15. Compact AC susceptometer for fast sample characterization down to 0.1 K

    Energy Technology Data Exchange (ETDEWEB)

    Yonezawa, Shingo, E-mail: yonezawa@scphys.kyoto-u.ac.jp; Higuchi, Takumi; Sugimoto, Yusuke; Sow, Chanchal; Maeno, Yoshiteru [Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan)

    2015-09-15

    We report a new design of an AC magnetic susceptometer compatible with the Physical Properties Measurement System (PPMS) by Quantum Design, as well as with its adiabatic demagnetization refrigerator option. With the elaborate compact design, the susceptometer allows simple and quick sample mounting process. The high performance of the susceptometer down to 0.1 K is demonstrated using several superconducting and magnetic materials. This susceptometer provides a method to quickly investigate qualities of a large number of samples in the wide temperature range between 0.1 and 300 K.

  16. Design study of 10 kW superconducting generator for wind turbine applications

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Mijatovic, Nenad; Seiler, Eugen

    2009-01-01

    = 1 Tesla to be similar to the performance of permanent magnets and to represent a layout, which can be scaled up in future off-shore wind turbines. The proposed generator is a 8 pole synchronous machine based on race-track coils of high temperature superconducting tapes and an air cored copper stator...

  17. Incorporating YBCO Coated Conductors in High-speed Superconducting Generators

    Science.gov (United States)

    2008-07-01

    4.0 kW/lb (8.82 kW/kg). The machine configuration chosen by GE for design was a homopolar inductor alternator (HIA) which locates the...extremely severe ac loss environment. Even if this is ultimately impossible for high speed generators, it may not preclude lower speed motors and

  18. Phase stability of superconductive Y1Ba2Cu4O8

    International Nuclear Information System (INIS)

    Hegde, M.S.; Kumaraswamy, B.V.; Pandey, S.P.; Narlikar, A.V.

    1997-01-01

    The stability of the 124 superconductive phase YBa 2 Cu 4 O 8 upon exposure to air and saturated humidity at ambient temperature has been studied by thermogravimetry, X-ray diffraction, and ac susceptometry. Extent of phase conversion was monitored by TG and confirmed by XRD and ac susceptometry. 124 samples upon prolonged exposure to air were found to be no longer phase-pure, with partial conversion to 123 and CuO. On oxygen annealing, reconversion of 123 + GuO to 124 was observed. However, upon prolonged exposure to saturated humid conditions, phase-pure 124 dissociated irreversibly into 211, GuO, and a highly disordered 124-like structure with planar defects along many hkl indices and was found to be nonsuperconducting even up to 60 K

  19. Four-layer, two-inch bore, superconducting dipole magnet

    International Nuclear Information System (INIS)

    Hassenzahl, W.V.; Peters, C.; Gilbert, W.; Taylor, C.; Meuser, R.

    1982-11-01

    Superconductors provide the accelerator designer with a unique opportunity to construct machines that can achieve high particle energies and yet have low operating costs. This paper describes the design, fabrication and testing of a 4 layer, 50 mm bore superconducting dipole magnet, D-9A. The magnet reached short sample, 5.8 T at 4.4 K and 8.0 T and 1.8 K, with little training, and exhibited low losses and low ramp rate sensitivity

  20. Advanced fusion technologies developed for JT-60 superconducting tokamak

    International Nuclear Information System (INIS)

    Sakasai, Akira; Ishida, S.; Matsukawa, M.

    2003-01-01

    The modification of JT-60U is planned as a full superconducting tokamak (JT-60SC). The objectives of the JT-60SC program are to establish scientific and technological bases for the steady-state operation of high performance plasmas and utilization of reduced-activation materials in economically and environmentally attractive DEMO reactor. Advanced fusion technologies relevant to DEMO reactor have been developed in the superconducting magnet technology and plasma facing components for the design of JT-60SC. To achieve a high current density in a superconducting strand, Nb 3 Al strands with a high copper ratio of 4 have been newly developed for the toroidal field coils (TFC) of JT-60SC. The R and D to demonstrate applicability of Nb 3 Al conductor to the TFC by a react-and-wind technique have been carried out using a full-size Nb 3 Al conductor. A full-size NbTi conductor with low AC loss using Ni-coated strands has been successfully developed. A forced cooling divertor component with high heat transfer using screw tubes has been developed for the first time. The heat removal performance of the CFC target was successfully demonstrated on the electron beam irradiation stand. (author)

  1. A 1.5 MJ cryostatic stable superconducting ohmic-heating coil

    International Nuclear Information System (INIS)

    Wang, S.-T.; Kim, S.H.; Praeg, W.F.; Krieger, C.I.

    1978-01-01

    As early as FY 1975, ANL had recognized the clear advantage of a superconducting ohmic-heating (OH) coil and proposed a five-year pulsed coil and power supply development program to ERDA. With modest funding made available by ERDA in FY 1977 and the use of substantial equipment inventory at ANL, a small but agressive development program was advanced to the construction of a 1.5 MJ model coil. The principle objective in building the 1.5 MJ ac coil is to demonstrate ac cryostability of a large coil with a dB/dt ranging from 2 T/s up to 14 T/s. The results of basic cable development and tests will be described. The design and construction of a prototype 1.5 MJ cryostable pulsed coil and its nonmetallic cryostat will be presented. (author)

  2. Majorana transport in superconducting nanowire with Rashba and Dresselhaus spin-orbit couplings.

    Science.gov (United States)

    You, Jia-Bin; Shao, Xiao-Qiang; Tong, Qing-Jun; Chan, A H; Oh, C H; Vedral, Vlatko

    2015-06-10

    The tunneling experiment is a key technique for detecting Majorana fermion (MF) in solid state systems. We use Keldysh non-equilibrium Green function method to study two-lead tunneling in superconducting nanowire with Rashba and Dresselhaus spin-orbit couplings. A zero-bias dc conductance peak appears in our setup which signifies the existence of MF and is in accordance with previous experimental results on InSb nanowire. Interestingly, due to the exotic property of MF, there exists a hole transmission channel which makes the currents asymmetric at the left and right leads. The ac current response mediated by MF is also studied here. To discuss the impacts of Coulomb interaction and disorder on the transport property of Majorana nanowire, we use the renormalization group method to study the phase diagram of the wire. It is found that there is a topological phase transition under the interplay of superconductivity and disorder. We find that the Majorana transport is preserved in the superconducting-dominated topological phase and destroyed in the disorder-dominated non-topological insulator phase.

  3. Majorana transport in superconducting nanowire with Rashba and Dresselhaus spin–orbit couplings

    International Nuclear Information System (INIS)

    You, Jia-Bin; Shao, Xiao-Qiang; Tong, Qing-Jun; Oh, C H; Vedral, Vlatko; Chan, A H

    2015-01-01

    The tunneling experiment is a key technique for detecting Majorana fermion (MF) in solid state systems. We use Keldysh non-equilibrium Green function method to study two-lead tunneling in superconducting nanowire with Rashba and Dresselhaus spin–orbit couplings. A zero-bias dc conductance peak appears in our setup which signifies the existence of MF and is in accordance with previous experimental results on InSb nanowire. Interestingly, due to the exotic property of MF, there exists a hole transmission channel which makes the currents asymmetric at the left and right leads. The ac current response mediated by MF is also studied here. To discuss the impacts of Coulomb interaction and disorder on the transport property of Majorana nanowire, we use the renormalization group method to study the phase diagram of the wire. It is found that there is a topological phase transition under the interplay of superconductivity and disorder. We find that the Majorana transport is preserved in the superconducting-dominated topological phase and destroyed in the disorder-dominated non-topological insulator phase. (paper)

  4. Advances in superconducting cyclotrons at MSU

    International Nuclear Information System (INIS)

    Blosser, H.; Antaya, T.; Au, R.

    1987-01-01

    Intensive work on superconducting cyclotrons began at MSU in late 1973 (a brief earlier study had occurred in the early 1960's) and continues vigorously at present. One large cyclotron, the ''K500'', has been operating for a number of years, a second, the ''K800'', is nearing completion, the first operating tests of its magnet having occurred at the time of the previous conference, and a third, the ''medical cyclotron'', is now also nearing completion with first operation of its magnet expected just after the present conference. These cyclotrons like other superconducting cyclotrons are all dramatically smaller than comparable room temperature machines; overall weight is typically about 1/20th of that of room temperature cyclotrons of the same energy. This large reduction in the quantities of materials is partially offset by added complexity, but finally, a net overall cost savings of 50 to 70 % typically results; as a consequence the superconducting cyclotron is widely viewed as the cyclotron of the future. The thirteen years of experience at MSU involving three of these cyclotrons, together with much important work at other laboratories, gives a rather clear view of the advantages and disadvantages of various design approaches including by now a rather significant period of long term evaluation. This paper reviews highlights of this program. (author)

  5. Liquid helium-free 15 T superconducting magnet at 4 K

    International Nuclear Information System (INIS)

    Sakuraba, J.; Mikami, Y.; Watazawa, K.; Watanabe, K.; Awaji, S.

    2000-01-01

    We have successfully demonstrated a 15.1 T liquid helium-free superconducting magnet with a room-temperature bore of 52 mm using a Nb 3 Sn/NbTi hybrid coil, Bi2223 current leads and two Gifford-McMahon cryocoolers. The magnet has 830 mm outside diameter, 1221 mm height and 720 kg weight. The magnet was cooled to 3.6 K in 114 h. A central magnetic field of 15.1 T was achieved in 38 min. The temperature of the coil increased to 5.7 K due to ac losses during the excitation, but it decreased to 4.0 K before reaching 15.1 T. The temperature of the coil remained at a constant value of 3.8 K over the 24 h of operation. The demonstration indicated the usefulness of a liquid helium-free superconducting magnet to generate high magnetic fields up to 15 T. (author)

  6. Superconductivity

    International Nuclear Information System (INIS)

    Caruana, C.M.

    1988-01-01

    Despite reports of new, high-temperature superconductive materials almost every day, participants at the First Congress on Superconductivity do not anticipate commercial applications with these materials soon. What many do envision is the discovery of superconducting materials that can function at much warmer, perhaps even room temperatures. Others hope superconductivity will usher in a new age of technology as semiconductors and transistors did. This article reviews what the speakers had to say at the four-day congress held in Houston last February. Several speakers voiced concern that the Reagan administration's apparent lack of interest in funding superconductivity research while other countries, notably Japan, continue to pour money into research and development could hamper America's international competitiveness

  7. Unusually large magnetic moments in the normal state and superconducting state of Sn nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Chi-Hang; Lee, Chi-Hung; Hsu, Chien-Kang; Li, Chi-Yen; Karna, Sunil K.; Wang, Chin-Wei; Wu, Chun-Ming; Li, Wen-Hsien, E-mail: whli@phy.ncu.edu.tw [National Central University, Department of Physics and Center for Neutron Beam Applications (China)

    2013-09-15

    We report on the observations of spontaneous magnetic moments in the normal as well as in the superconducting states of a 9 nm Sn nanoparticle assembly, through X-ray diffraction, magnetization, ac magnetic susceptibility, and neutron diffraction measurements. The saturation magnetization reaches an unexpectedly large value of 1.04 emu/g at 5 K, with a temperature profile that can be described by Bloch's law with an exponent of b = 1.8. A magnetic moment of Left-Pointing-Angle-Bracket {mu}{sub Z} Right-Pointing-Angle-Bracket = 0.38 {mu}{sub B} develops after cooling from 260 to 4 K. Superconductivity develops below T{sub C} = 3.98 K, which is 7 % higher than the T{sub C} = 3.72 K of bulk Sn. Surprisingly, an addition magnetic moment of Left-Pointing-Angle-Bracket {mu}{sub Z} Right-Pointing-Angle-Bracket = 0.05 {mu}{sub B} develops upon entering the superconducting state.

  8. Imaging the Statics and Dynamics of Superconducting Vortices and Antivortices Induced by Magnetic Microdisks

    Directory of Open Access Journals (Sweden)

    R. B. G. Kramer

    2011-10-01

    Full Text Available If a magnet of microscopic dimensions is brought in close proximity to a superconductor, the quantized nature of their interaction due to the creation of flux quanta in the superconducting system becomes noticeable. Herein, we directly image, via scanning Hall microscopy, the vortex-antivortex pairs in a superconducting film created by micromagnets. The number of antivortices at equilibrium conditions can be changed either by tuning the magnetic moment of the magnets or by annihilation with externally induced vortices. We demonstrate that small ac field excitations shake the antivortices sitting next to the micromagnets whereas no sizable motion is observed for the vortices sitting on top of the magnets, clearly revealing the different mobility of these two vortex species. A metastable state, which is obtained by applying a field after the system has been cooled down below the superconducting transition, shows a complex graded distribution of coexisting vortices and antivortices forming an intertwined critical state.

  9. Technological stakes of LHC, the large superconducting collider in project at CERN

    International Nuclear Information System (INIS)

    Lebrun, P.

    1991-01-01

    The LHC large superconducting particle collider project is presented, with particular emphasis on its major technological requirements and returns, mostly in the domains of high-field electromagnets, superfluid helium cryogenics, and integration of such advanced techniques in a large machine. The corresponding cooperation and technological transfer to European laboratories and industries are briefly discussed [fr

  10. Study of the electric Held in HTS tape caused by perpendicular AC magnetic field

    International Nuclear Information System (INIS)

    Roiberg, V; Kopansky, F.

    2004-01-01

    Full Text: In a previous work we studied the influence of AC magnetic fields on voltage-currents (V-I) characteristics of high temperature superconducting (HTS) multi filament BSCC0-2223 tapes. It was found that AC magnetic fields perpendicular to the ab plane (the wide surface of the tape) cause a linear decrease of the critical current (IC) with amplitude of the AC magnetic field. The degradation of IC in .AC field was explained by the geometrical model according to which the transport current floe: is confined to the central zone of the tape where .AC field does not penetrate. For deeper understanding of the observed phenomena we carried out a study of the time dependence of the electric field during the cycle of AC field. At the same time we expanded the frequency range to low frequencies down to 1 Hz. The main results of the work are as following. 1. The time modulation of the electric field E in the HTS tape carrying transport DC current has the double frequency relating to AC magnetic field. 2. In field amplitudes less than 70 G the electric field modulation decreases with increasing frequency in opposite to its well-pronounced increase in higher AC field amplitudes. Alcove 70 G, the electric field increases with increasing the frequency of the external magnetic field. The wave forms of the electric field are different in both amplitudes ranges. 3. E-I curves of the tape in low amplitudes are frequency independent and coincide with E-l curves in AC field with intensity equal to the AC field amplitude. 4. In high AC field amplitudes, a strong dependence of the E-I curves on frequency is observed in the frequency range of 1-40 Hz and no dependence is observed in higher frequencies. Our results suggest that a combination of the geometrical model with flux creep concepts is necessary for a better understanding of the electric field behavior in our measurement conditions

  11. Performance of an X-ray single pixel TES microcalorimeter under DC and AC biasing

    International Nuclear Information System (INIS)

    Gottardi, L.; Kuur, J. van der; Korte, P. A. J. de; Den Hartog, R.; Dirks, B.; Popescu, M.; Hoevers, H. F. C.; Bruijn, M.; Borderias, M. Parra; Takei, Y.

    2009-01-01

    We are developing Frequency Domain Multiplexing (FDM) for the read-out of TES imaging microcalorimeter arrays for future X-ray missions like IXO. In the FDM configuration the TES is AC voltage biased at a well defined frequencies (between 0.3 to 10 MHz) and acts as an AM modulating element. In this paper we will present a full comparison of the performance of a TES microcalorimeter under DC bias and AC bias at a frequency of 370 kHz. In both cases we measured the current-to-voltage characteristics, the complex impedance, the noise, the X-ray responsivity, and energy resolution. The behaviour is very similar in both cases, but deviations in performances are observed for detector working points low in the superconducting transition (R/R N <0.5). The measured energy resolution at 5.89 keV is 2.7 eV for DC bias and 3.7 eV for AC bias, while the baseline resolution is 2.8 eV and 3.3 eV, respectively.

  12. Homopolar machine design

    International Nuclear Information System (INIS)

    Thullen, P.

    1978-01-01

    A general conceptual design for a disc-type homopolar machine is presented. This machine uses a superconducting, air-core, solenoidal field winding with a peak field of 8 T. A total energy of 500 MJ is stored in two counter-rotating disc rotors that operate at a surface speed of 200 m/s. Terminal voltages of 500 to 2000 V are obtained over the range of designs studied. Brush systems to collect 3 MA are investigated. Various brush materials are discussed to determine their usefulness in this application. Sufficient information on operating characteristics in high-power applications is only available for copper-graphite brushes. The use of sliding brushes for terminal voltage regulation is discussed. This feature cannot provide a great deal of flexibility in this particular application although it may be useful during start-up. The brush system is the most demanding feature of this design. Few systems in the million ampere range have been constructed, consequently, it is not possible to predict the behavior of this brush system with great certainty. A detailed design of the brushes should be undertaken. It is estimated that the cost of such a machine will range from 0.5 to 1.5 cents per joule

  13. The superconducting x-ray lithography source program at Brookhaven

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G. P.; Heese, R. N.; Vignola, G.; Murphy, J. B.; Godel, J. B.; Hsieh, H.; Galayda, J.; Seifert, A.; Knotek, M. L.

    1989-07-01

    A compact electron storage ring with superconducting dipole magnets, is being developed at the National Synchrotron Light Source at Brookhaven. The parameters of the source have been optimized for its future use as an x-ray source for lithography. This first ring is a prototype which will be used to study the operating characteristics of machines of this type with particular attention being paid to low-energy injection and long beam lifetime.

  14. A new approach for AC loss reduction in HTS transformer using auxiliary windings, case study: 25 kA HTS current injection transformer

    Science.gov (United States)

    Heydari, Hossein; Faghihi, Faramarz; Aligholizadeh, Reza

    2008-01-01

    AC loss is one of the important parameters in HTS (high temperature superconducting) AC devices. Among the HTS AC power devices, the transformer is an essential part in the electrical power system. The AC losses in an HTS tape depend on the magnetic field. One of the techniques usually adopted to mitigate the unwanted magnetic field is using a system of coils that produce a magnetic field opposite to the incident one, reducing the total magnetic field. In this paper adding two auxiliary windings to the HTS transformer to produce this opposite magnetic field is proposed. The proper use of these auxiliary windings could reduce the leakage flux and, therefore, the AC loss. A mathematical model is used to describe the behaviour of a transformer operating with auxiliary windings, based on the theory of electromagnetic coupled circuits. The influence of the auxiliary windings on the leakage field is studied by the finite element method (FEM) and the AC loss of an HTS transformer was calculated. Also, the simulation results show that employing auxiliary windings will improve the HTS transformer efficiency.

  15. A new approach for AC loss reduction in HTS transformer using auxiliary windings, case study: 25 kA HTS current injection transformer

    International Nuclear Information System (INIS)

    Heydari, Hossein; Faghihi, Faramarz; Aligholizadeh, Reza

    2008-01-01

    AC loss is one of the important parameters in HTS (high temperature superconducting) AC devices. Among the HTS AC power devices, the transformer is an essential part in the electrical power system. The AC losses in an HTS tape depend on the magnetic field. One of the techniques usually adopted to mitigate the unwanted magnetic field is using a system of coils that produce a magnetic field opposite to the incident one, reducing the total magnetic field. In this paper adding two auxiliary windings to the HTS transformer to produce this opposite magnetic field is proposed. The proper use of these auxiliary windings could reduce the leakage flux and, therefore, the AC loss. A mathematical model is used to describe the behaviour of a transformer operating with auxiliary windings, based on the theory of electromagnetic coupled circuits. The influence of the auxiliary windings on the leakage field is studied by the finite element method (FEM) and the AC loss of an HTS transformer was calculated. Also, the simulation results show that employing auxiliary windings will improve the HTS transformer efficiency

  16. A new approach for AC loss reduction in HTS transformer using auxiliary windings, case study: 25 kA HTS current injection transformer

    Energy Technology Data Exchange (ETDEWEB)

    Heydari, Hossein; Faghihi, Faramarz; Aligholizadeh, Reza [Center of Excellence for Power System Automation and Operation, Electrical Engineering Department, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

    2008-01-15

    AC loss is one of the important parameters in HTS (high temperature superconducting) AC devices. Among the HTS AC power devices, the transformer is an essential part in the electrical power system. The AC losses in an HTS tape depend on the magnetic field. One of the techniques usually adopted to mitigate the unwanted magnetic field is using a system of coils that produce a magnetic field opposite to the incident one, reducing the total magnetic field. In this paper adding two auxiliary windings to the HTS transformer to produce this opposite magnetic field is proposed. The proper use of these auxiliary windings could reduce the leakage flux and, therefore, the AC loss. A mathematical model is used to describe the behaviour of a transformer operating with auxiliary windings, based on the theory of electromagnetic coupled circuits. The influence of the auxiliary windings on the leakage field is studied by the finite element method (FEM) and the AC loss of an HTS transformer was calculated. Also, the simulation results show that employing auxiliary windings will improve the HTS transformer efficiency.

  17. Programs on large scale applications of superconductivity in Japan

    International Nuclear Information System (INIS)

    Yasukochi, K.; Ogasawara, T.

    1974-01-01

    History of the large scale application of superconductivity in Japan is reported. Experimental works on superconducting magnet systems for high energy physics have just begun. The programs are described by dividing into five categories: 1) MHD power generation systems, 2) superconducting rotating machines, 3) cryogenic power transmission systems, 4) magnetically levitated transportation, and 5) application to high energy physics experiments. The development of a big superconducting magnet for a 1,000 kW class generator was set up as a target of first seven year plan, which came to end in 1972, and continues for three years with the budget of 900 million yen from 1973 on. In the second phase plan, a prototype MHD generator is argued. A plan is contemplated to develop a synchronous generator with inner rotating field by Fuji Electric Co. The total budget for the future plans of superconducting power transmission system amounts to 20 billion yen for the first period of 8 approximately 9 years. In JNR's research and development efforts, several characteristic points are picked up: 1) linear motor drive with active side on ground, 2) loop track, 3) combined test run of maglev and LSM. The field test at the speed of 500 km/hr on a 7 km track is scheduled to be performed in 1975. The target of operation is in 1985. A 12 GeV proton synchrotron is now under construction for the study on high energy physics. Three ring intersecting storage accelerator is discussed for future plan. (Iwakiri, K.)

  18. 1998 Annual Study Report. Research and development of power storage by high-temperature superconducting flywheels. Research and development of high-temperature superconducting materials; 1998 nendo seika hokokusho. Koon chodendo flywheel denryoku chozo kenkyu kaihatsu (koon chodendozai no kenkyu kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    This R and D program is aimed at optimization of superconductors for improved levitation force of the superconducting magnetic bearings which support a 10 MWh power storage system by high-temperature superconducting flywheel (FW), to clarify possibility of sizing up the FW body and R and D themes for the commercialization. The processes are screened to simultaneously solve the conflicting targets of sizing up the sample of the Y-based bulk superconducting material and improved crystal orientation of the whole bearing, leading to selection of multi-seeding. The sample made on a trial basis improves levitation force by approximately 30%. It is considered that the OCMG-processed rare-earth-based superconducting material can generate very strong electromagnetic force, when combined with a permanent magnet. The Ag-doped Sm-based bulk material shows a reduced creep-caused loss of loading force, and a lower loss of Jc resulting from increased temperature than the Y-based one, decreasing AC loss and controlling temperature rise. The running characteristics and mechanical strength of the FW, and causes for temporal changes are investigated, in order to evaluate the superconducting material characteristics. (NEDO)

  19. Influence of AC external magnetic field perturbation on the guidance force of HTS bulk over a NdFeB guideway

    International Nuclear Information System (INIS)

    Zhang Longcai; Wang Jiasu; Wang Suyu; He Qingyong

    2007-01-01

    Superconducting maglev vehicle system requires that the surface magnetic field of the guideway is uniform along the forward direction. But in practice the surface magnetic field of the NdFeB permanent magnet guideway is not always immutable. So the HTS bulks in this case are exposed to AC external magnetic field, which may induce the energy loss in the bulk and influence the guidance force between the HTS bulks and the NdFeB guideway. In this paper, we experimentally studied the influence of the AC external magnetic field perturbation on the guidance force of a HTS bulk over the NdFeB guideway. The experimental results showed that the guidance force was influenced by the application of the AC external magnetic. The guidance fore hysteresis became more evident with the amplitude of the AC field and was independent of the frequency in the range 90-400 Hz. We attributed the reason to magnetic hysteresis loss in the superconductor

  20. Influence of AC external magnetic field perturbation on the guidance force of HTS bulk over a NdFeB guideway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Longcai [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China)]. E-mail: zhlcai2000@163.com; Wang Jiasu [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China); Wang Suyu [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China); He Qingyong [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China)

    2007-08-01

    Superconducting maglev vehicle system requires that the surface magnetic field of the guideway is uniform along the forward direction. But in practice the surface magnetic field of the NdFeB permanent magnet guideway is not always immutable. So the HTS bulks in this case are exposed to AC external magnetic field, which may induce the energy loss in the bulk and influence the guidance force between the HTS bulks and the NdFeB guideway. In this paper, we experimentally studied the influence of the AC external magnetic field perturbation on the guidance force of a HTS bulk over the NdFeB guideway. The experimental results showed that the guidance force was influenced by the application of the AC external magnetic. The guidance fore hysteresis became more evident with the amplitude of the AC field and was independent of the frequency in the range 90-400 Hz. We attributed the reason to magnetic hysteresis loss in the superconductor.

  1. Program for development of high-field superconducting magnets for fusion research

    International Nuclear Information System (INIS)

    1975-01-01

    Three superconducting magnet programs at LLL are outlined. The first program, the one considered in greatest detail, is a developmental program in which LLL will work closely with superconductor manufacturers to develop multifilamentary Nb 3 Sn superconductor suitable for use in large CTR magnets. The result of this program will be the fabrication of a rather large magnet (but one that is much smaller than future CTR magnets) and the determination of its performance limitations. In the second program, the developed multifilamentary Nb 3 Sn superconductor will be used to construct the magnets for the Fusion Engineering Research Facility (FERF) machine. In this program, the bulk of the effort will be in magnet design and winding. The third program chronologically overlaps the first two programs. This program includes the fabrication and testing of the superconducting magnets for the MX machine although, as explained in the Technical Plan, only the cost of the development work is included in this document. At the present time, Nb--Ti superconductor is being considered. Apart from some initial conductor design work, the major effort will be in magnet design and winding

  2. An overview of rotating machine systems with high-temperature bulk superconductors

    Science.gov (United States)

    Zhou, Difan; Izumi, Mitsuru; Miki, Motohiro; Felder, Brice; Ida, Tetsuya; Kitano, Masahiro

    2012-10-01

    The paper contains a review of recent advancements in rotating machines with bulk high-temperature superconductors (HTS). The high critical current density of bulk HTS enables us to design rotating machines with a compact configuration in a practical scheme. The development of an axial-gap-type trapped flux synchronous rotating machine together with the systematic research works at the Tokyo University of Marine Science and Technology since 2001 are briefly introduced. Developments in bulk HTS rotating machines in other research groups are also summarized. The key issues of bulk HTS machines, including material progress of bulk HTS, in situ magnetization, and cooling together with AC loss at low-temperature operation are discussed.

  3. Commissioning and operating experience with the LISA superconducting accelerator

    International Nuclear Information System (INIS)

    Castellano, M.; Ferrario, M.; Minestrini, M.; Patteri, P.; Tazzioli, F.; Kulinski, S.

    1996-06-01

    The commissioning of the LISA superconducting (SC) RF electron linac at INFN Frascati Laboratories has been concluded although, due to a change in program priorities, the full possibilities of the machine have not been exploited. In this report the authors illustrate the results achieved so far and the difficulties encountered in commissioning, with the hope that this material might be some of help to those who intend to start the enterprise of building a SC linac in a non specialized environment. The part concerning the SC system is particularly stressed, but a relevant attention is also devoted to the traditional room temperature injector, the proper setting of which is fundamental to achieving the high beam quality that such a machine allows

  4. Co60 and Cs137 gamma radiation effects on textured bscco Superconducting fibers

    International Nuclear Information System (INIS)

    Leyva Fabelo, A.; Bouza Dominguez, J.; Cruz Inclan, Crlos M.

    2001-01-01

    Bi2Sr2CaCu2Ox superconducting fibers synthesized by solid state reaction and textured by the method of zonal laser ablation were irradiated with gamma rays of 1.25 MeV and 662 keV and studied the behavior of some of its properties with the exposition dose. The measurements of dynamic magnetic susceptibility were used for the characterization of the samples. It was observed that for the dose of up to 600 kGy in the case of the Co60 and until 500 mGy for the Cs137, the fibers preserve its superconducting intragrain properties. It is an evidence of the high resistance of the material to the radiacional damage. In all the cases were verified that with the increase of the dose the Ton of the transition grows. Two possible mechanisms that play the most important role in this effect are explained in the text. The ac measurements allowed to verified the increasing behavior of the superconducting volume fraction in the sample with the exposition dose

  5. Shooting quasiparticles from Andreev bound states in a superconducting constriction

    Energy Technology Data Exchange (ETDEWEB)

    Riwar, R.-P.; Houzet, M.; Meyer, J. S. [University of Grenoble Alpes, INAC-SPSMS (France); Nazarov, Y. V., E-mail: Y.V.Nazarov@tudelft.nl [Delft University of Technology, Kavli Institute of NanoScience (Netherlands)

    2014-12-15

    A few-channel superconducting constriction provides a set of discrete Andreev bound states that may be populated with quasiparticles. Motivated by recent experimental research, we study the processes in an a.c. driven constriction whereby a quasiparticle is promoted to the delocalized states outside the superconducting gap and flies away. We distinguish two processes of this kind. In the process of ionization, a quasiparticle present in the Andreev bound state is transferred to the delocalized states leaving the constriction. The refill process involves two quasiparticles: one flies away while another one appears in the Andreev bound state. We notice an interesting asymmetry of these processes. The electron-like quasiparticles are predominantly emitted to one side of the constriction while the hole-like ones are emitted to the other side. This produces a charge imbalance of accumulated quasiparticles, that is opposite on opposite sides of the junction. The imbalance may be detected with a tunnel contact to a normal metal lead.

  6. On/Off Power Supply of the Electron Beam Machine HV Automation by Using PCL-718 and PCLD-786

    International Nuclear Information System (INIS)

    Sudiyanto; Suyono, Djoko; Salam, Aminus; Ngatinu; Sudaryanto; Wiyana, Badi

    1996-01-01

    HV on/off power supply of the electron beam machine HV automation by using PCL-718 and PCLD-786 have been done. During the simulation experiments by using PCL-718 ADC-12 bit and PCLD-786 driver relay and Turbo-C software have been multiplexes 16 differential digital output channels which controlled on/off ac/dc relay of the electron beam machine power supply. Two PCLD-786 can be cascaded to expand the digital output channels which controlled 32 ac/dc relay

  7. Study on interstrand coupling losses in Rutherford-type superconducting cables

    International Nuclear Information System (INIS)

    Lei, Y.Z.; Shintomi, T.; Terashima, A.; Hirabayashi, H.

    1993-02-01

    Two sets of experimental apparatus for measuring the AC losses in superconducting strands and Rutherford-type cable conductors have been constructed. A few strand samples and a number of compacted cable samples with and without a CuMn matrix have been measured. The hysteresis loss, loss from coupling within strands and loss from coupling between strands in cables have been distinguished from each other. The results show that, even for Rutherford cables without any soldering and coating, their AC losses may be quite different from each other due to the variation of the interstrand coupling loss. For cables without a CuMn matrix, interstrand coupling loss increases nearly according to a geometrical series with an increase of curing temperature simulating coil fabrication. However, cables with the CuMn matrix show a relatively small curing temperature dependence. For most of the samples, losses do not show any evident dependence on the mechanical pressure. Interstrand resistances in one of these cables have also been measured; the results indicate that the tendency for a decrease in the interstrand resistances is consistent with the results of AC loss measurements. (author)

  8. Of Slot Machines and Broken Test Tubes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Of Slot Machines and Broken Test Tubes. S Mahadevan. General Article Volume 19 Issue 5 May 2014 pp 395-405. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/019/05/0395-0405. Keywords.

  9. Introduction to Machine Protection

    CERN Document Server

    Schmidt, R

    2016-01-01

    Protection of accelerator equipment is as old as accelerator technology and was for many years related to high-power equipment. Examples are the protection of powering equipment from overheating (magnets, power converters, high-current cables), of superconducting magnets from damage after a quench and of klystrons. The protection of equipment from beam accidents is more recent, although there was one paper that discussed beam-induced damage for the SLAC linac (Stanford Linear Accelerator Center) as early as in 1967. It is related to the increasing beam power of high-power proton accelerators, to the emission of synchrotron light by electron-positron accelerators and to the increase of energy stored in the beam. Designing a machine protection system requires an excellent understanding of accelerator physics and operation to anticipate possible failures that could lead to damage. Machine protection includes beam and equipment monitoring, a system to safely stop beam operation (e.g. dumping the beam or stopping ...

  10. Superconducting magnetic energy storage (SMES) program. January 1--December 31, 1978

    International Nuclear Information System (INIS)

    Rogers, J.D.

    1979-02-01

    Work is reported on the development of two superconducting magnetic energy storage units. One is a 30-MJ unit for use by the Bonneville Power Administration to stabilize power oscillations on their Pacific AC Intertie, and the second is a 1- to 10-GWh unit for use as a diurnal load-leveling device. Emphasis has been placed on the stabilizing system. The engineering specification design of the 30-MJ superconducting coil was completed and a contract will be placed for the coil fabrication design. Bids have been received for the stabilizing system 10-MW converter and coil protective dump resistor. These components will be purchased in 1979. The reference design for the 1- to 10-GWh diurnal load-leveling unit has been totally revised and is being assembled in redrafted report form. Plans are to build a 10- to 30-MWh prototype diurnal load-leveling demonstration unit

  11. Transverse ratchet effect and superconducting vortices: simulation and experiment

    International Nuclear Information System (INIS)

    Dinis, L; Parrondo, J M R; Perez de Lara, D; Gonzalez, E M; Vicent, J L; Anguita, J V

    2009-01-01

    A transverse ratchet effect has been measured in magnetic/superconducting hybrid films fabricated by electron beam lithography and magnetron sputtering techniques. The samples are Nb films grown on top of an array of Ni nanotriangles. Injecting an ac current parallel to the triangle reflection symmetry axis yields an output dc voltage perpendicular to the current, due to a net motion of flux vortices in the superconductor. The effect is reproduced by numerical simulations of vortices as Langevin particles with realistic parameters. Simulations provide an intuitive picture of the ratchet mechanism, revealing the fundamental role played by the random intrinsic pinning of the superconductor.

  12. Superconducting proximity effect in mesoscopic superconductor/normal-metal junctions

    CERN Document Server

    Takayanagi, H; Toyoda, E

    1999-01-01

    The superconducting proximity effect is discussed in mesoscopic superconductor/normal-metal junctions. The newly-developed theory shows long-range phase-coherent effect which explaines early experimental results of giant magnetoresistance oscillations in an Andreev interferometer. The theory also shows that the proximity correction to the conductance (PCC) has a reentrant behavior as a function of energy. The reentrant behavior is systematically studied in a gated superconductor-semiconductor junction. A negative PCC is observed in the case of a weak coupling between the normal metal and the external reservoir. Phase coherent ac effect is also observed when rf is irradiated to the junction.

  13. Magnetization measurement of niobium for superconducting cavity material evaluation

    International Nuclear Information System (INIS)

    Wake, Masayoshi; Saito, Kenji.

    1995-05-01

    A series of magnetization measurements on niobium materials for superconducting cavities was performed, and the method was found to be very useful for material evaluation. The effects of annealing, chemical polishing and machining were clearly observed by this method. The material quality and the processing of the material can be properly evaluated by measuring the magnetization. An observation of the Q-disease effect indicates the possibility of using this method for the studies beyond material evaluation. (J.P.N)

  14. Inductive voltage compensation in superconducting magnet systems

    International Nuclear Information System (INIS)

    Yeh, H.T.; Goddard, J.S.; Shen, S.S.

    1979-01-01

    This paper details several techniques of inductive voltage compensation developed for quench detection in superconducting magnet systems with multiple coils and power supplies, with particular application for the Large Coil Test Facility (LCTF). Sources of noise, their magnitudes, and the sensitivity required for normal zone detection to avoid damage to the magnets are discussed. Two passive compensation schemes (second difference and central difference) are introduced and illustrated by parameters of LCTF; these take advantage of coil symmetries and other system characteristics. An active compensation scheme based on current rate input fom pickup coils and utilizing theory on ac loss voltage for calibration was tested, and the experimental setup and test results are discussed

  15. Testing and Modeling of Machine Properties in Resistance Welding

    DEFF Research Database (Denmark)

    Wu, Pei

    The objective of this work has been to test and model the machine properties including the mechanical properties and the electrical properties in resistance welding. The results are used to simulate the welding process more accurately. The state of the art in testing and modeling machine properties...... as real projection welding tests, is easy to realize in industry, since tests may be performed in situ. In part II, an approach of characterizing the electrical properties of AC resistance welding machines is presented, involving testing and mathematical modelling of the weld current, the firing angle...... in resistance welding has been described based on a comprehensive literature study. The present thesis has been subdivided into two parts: Part I: Mechanical properties of resistance welding machines. Part II: Electrical properties of resistance welding machines. In part I, the electrode force in the squeeze...

  16. The attenuation of the levitation force of HTS bulk exposed to AC magnetic field on the above NdFeB guideway

    International Nuclear Information System (INIS)

    Liu Minxian; Wang Yan

    2012-01-01

    The characteristic of the levitation force relaxation was studied by experiment. The levitation force is attenuated with the application of the AC external magnetic field. The decay increases with the amplitude of the A external magnetic field. The decay is almost independent of the frequency of AC field. In the present High Temperature Superconducting (HTS) maglev vehicle system, the air gaps between the adjacent permanent magnets make the magnetic fields above the NdFeB guideway non-uniform. So it is required to study the characteristics of levitation force of the HTS bulk affected by the non-uniform applied magnetic fields along the moving direction. In this paper, we have studied the characteristics of the levitation force relaxation by an experiment in which AC magnetic field generated by an electromagnet is used to simulate the time-varying magnetic field caused by the inhomogeneity of the NdFeB guideway. From the experiment results, it is found that the levitation force is attenuated with the application of the AC field, and the attenuation is increased with the amplitude of the AC field, but the attenuation is almost independent of the frequency the AC magnetic field.

  17. The attenuation of the levitation force of HTS bulk exposed to AC magnetic field on the above NdFeB guideway

    Energy Technology Data Exchange (ETDEWEB)

    Liu Minxian, E-mail: liukey_sjtu@263.net [School of Computer Science and Technology, Southwest University of Science and Technology, Mianyang, Sichuan 621010 (China); Wang Yan [Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China)

    2012-01-15

    The characteristic of the levitation force relaxation was studied by experiment. The levitation force is attenuated with the application of the AC external magnetic field. The decay increases with the amplitude of the A external magnetic field. The decay is almost independent of the frequency of AC field. In the present High Temperature Superconducting (HTS) maglev vehicle system, the air gaps between the adjacent permanent magnets make the magnetic fields above the NdFeB guideway non-uniform. So it is required to study the characteristics of levitation force of the HTS bulk affected by the non-uniform applied magnetic fields along the moving direction. In this paper, we have studied the characteristics of the levitation force relaxation by an experiment in which AC magnetic field generated by an electromagnet is used to simulate the time-varying magnetic field caused by the inhomogeneity of the NdFeB guideway. From the experiment results, it is found that the levitation force is attenuated with the application of the AC field, and the attenuation is increased with the amplitude of the AC field, but the attenuation is almost independent of the frequency the AC magnetic field.

  18. Magnetic and superconducting properties of Ir-doped EuFe2As2

    International Nuclear Information System (INIS)

    B Paramanik, U; Hossain, Z; L Paulose, P; Ramakrishnan, S; K Nigam, A; Geibel, C

    2014-01-01

    The magnetic and superconducting properties of 14% Ir-doped EuFe 2 As 2 are studied by means of dc and ac magnetic susceptibilities, electrical resistivity, specific heat and 151 Eu and 57 Fe Mössbauer spectroscopy (MS) measurements. Doping of Ir in EuFe 2 As 2 suppresses the Fe spin density wave transition and in turn gives rise to high temperature superconductivity below 22.5 K with a reentrant feature at lower temperature. Magnetization and 151 Eu Mössbauer data indicate that the Eu 2+ spins order magnetically below 18 K. 57 Fe MS studies show a line broadening in the absorption spectra below 18 K due to transferred hyperfine field from the magnetically ordered Eu sublattices. A pronounced λ-shape peak in the specific heat supports a second-order phase transition of Eu 2+ magnetic ordering with a strong ferromagnetic component, as confirmed by the magnetic field dependences of the transition. For a single crystal, the in-plane resistivity (ρ ab ) and out-of-plane susceptibility (χ c ) show superconducting transitions with zero resistance and diamagnetism, respectively. But the in-plane susceptibility (χ ab ) does not show any diamagnetic shielding against external fields. The observed non-zero resistance in the temperature range 10–17.5 K, below the superconducting transition temperature, suggests the possible existence of a spontaneous vortex state in this superconductor. (papers)

  19. Calculation of alternating current losses in stacks and coils made of second generation high temperature superconducting tapes for large scale applications

    DEFF Research Database (Denmark)

    Zermeno, Victor M. R.; Abrahamsen, Asger Bech; Mijatovic, Nenad

    2013-01-01

    A homogenization method to model a stack of second generation High Temperature Superconducting tapes under AC applied transport current or magnetic field has been obtained. The idea is to find an anisotropic bulk equivalent for the stack such that the geometrical layout of the internal alternatin...

  20. Interface superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gariglio, S., E-mail: stefano.gariglio@unige.ch [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland); Gabay, M. [Laboratoire de Physique des Solides, Bat 510, Université Paris-Sud 11, Centre d’Orsay, 91405 Orsay Cedex (France); Mannhart, J. [Max Planck Institute for Solid State Research, 70569 Stuttgart (Germany); Triscone, J.-M. [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland)

    2015-07-15

    Highlights: • We discuss interfacial superconductivity, a field boosted by the discovery of the superconducting interface between LaAlO. • This system allows the electric field control and the on/off switching of the superconducting state. • We compare superconductivity at the interface and in bulk doped SrTiO. • We discuss the role of the interfacially induced Rashba type spin–orbit. • We briefly discuss superconductivity in cuprates, in electrical double layer transistor field effect experiments. • Recent observations of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3} are presented. - Abstract: Low dimensional superconducting systems have been the subject of numerous studies for many years. In this article, we focus our attention on interfacial superconductivity, a field that has been boosted by the discovery of superconductivity at the interface between the two band insulators LaAlO{sub 3} and SrTiO{sub 3}. We explore the properties of this amazing system that allows the electric field control and on/off switching of superconductivity. We discuss the similarities and differences between bulk doped SrTiO{sub 3} and the interface system and the possible role of the interfacially induced Rashba type spin–orbit. We also, more briefly, discuss interface superconductivity in cuprates, in electrical double layer transistor field effect experiments, and the recent observation of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3}.

  1. Thermal and electrodynamical formation mechanisms of overloaded AC states and charging rate influence on their stable dynamics

    International Nuclear Information System (INIS)

    Romanovskii, V.; Watanabe, K.; Awaji, S.

    2013-01-01

    Highlights: •Overloaded AC states are investigated to understand the mechanisms of there formation. •There exist characteristic time windows defining the existence of stable overloaded AC states. •Limiting values of the electric field, current and temperature are higher than the quench ones. -- Abstract: The macroscopic thermal and electrodynamical phenomena occurring in high-T c superconductors during overloaded AC states are theoretically investigated to understand the basic physical mechanisms, which are characteristic for the stable formation of the operating modes when the peak current exceeds the critical current of a superconductor during AC modes. It is shown that there exist characteristic time windows defining the existence of stable overloaded AC states. They identify the stability boundary of the overloaded AC states. Therefore, there is the maximum allowable value of a peak current of stable overloaded AC regimes at the given charging rate, cooling conditions and properties of a superconductor and a matrix. The results obtained prove that the limiting peak current is higher than the corresponding quench current defining the stability margin of DC states. It monotonically increases with the charging rate. Besides, in the stable overloaded AC states, the peak values of the electric field and temperature may be also noticeably higher than the corresponding quench values. They depend on the peak current and charging rate at the given cooling conditions. As a result, high-T c superconducting tapes can stably work under intensive AC modes without instability onset when the peak of applied currents may significantly exceed not only the critical current but also the corresponding values of DC-quench currents

  2. Superconducting coil and method of stress management in a superconducting coil

    Science.gov (United States)

    McIntyre, Peter M.; Shen, Weijun; Diaczenko, Nick; Gross, Dan A.

    1999-01-01

    A superconducting coil (12) having a plurality of superconducting layers (18) is provided. Each superconducting layer (18) may have at least one superconducting element (20) which produces an operational load. An outer support structure (24) may be disposed outwardly from the plurality of layers (18). A load transfer system (22) may be coupled between at least one of the superconducting elements (20) and the outer support structure (24). The load transfer system (22) may include a support matrix structure (30) operable to transfer the operational load from the superconducting element (20) directly to the outer support structure (24). A shear release layer (40) may be disposed, in part, between the superconducting element (20) and the support matrix structure (30) for relieving a shear stress between the superconducting element (20) and the support matrix structure (30). A compliant layer (42) may also be disposed, in part, between the superconducting element (20) and the support matrix structure (30) for relieving a compressive stress on the superconducting element (20).

  3. A monitoring of superconducting magnets by acoustic emission

    International Nuclear Information System (INIS)

    Nomura, Harehiko; Tateishi, Hiroshi; Onishi, Toshitada

    1990-01-01

    Since superconducting magnets (SCM) are going to be indispensable to magnetic levitated train, nuclear fusion, magnetic resonating imaging, rotational machines, etc., they must be placed great reliance on its repetitional operations. But without appropriate evaluating methods, these promising techniques must remain still in science levels and hard to be transferable to real human technologies. SCM, being used under dynamical operation with linking other electro-magnetic systems as said above, induce high voltage from which monitoring superconducting to normal transitional voltage is difficult to distinguish. To solve this problem, monitoring SCM by Acoustic Emission (AE) from themselves, have been found effective, in particular, during the dynamical energizing of them. As for a demonstration, this paper will report mainly how to monitor 3 MJ-SCM and a few results of the experiments aquired both by counting and locational mode of AE in pulsed and repeated operations of the magnet. Some discussions on the AE monitorings are also made along the main issues to be solved in future. (author)

  4. SUPERCONDUCTING DIPOLE MAGNETS FOR THE LHC INSERTION REGIONS

    International Nuclear Information System (INIS)

    WILLEN, E.; ANERELLA, M.; COZZOLINO, J.; GANETIS, G.; GHOSH, A.; GUPTA, R.; HARRISON, M.; JAIN, A.; MARONE, A.; MURATORE, J.; PLATE, S.; SCHMALZLE, J.; WANDERER, P.; WU, K.C.

    2000-01-01

    Dipole bending magnets are required to change the horizontal separation of the two beams in the LHC. In Intersection Regions (IR) 1, 2, 5, and 8, the beams are brought into collision for the experiments located there. In IR4, the separation of the beams is increased to accommodate the machine's particle acceleration hardware. As part of the US contribution to the LHC Project, BNL is building the required superconducting magnets. Designs have been developed featuring a single aperture cold mass in a single cryostat, two single aperture cold masses in a single cryostat, and a dual aperture cold mass in a single cryostat. All configurations feature the 80 mm diameter, 10 m long superconducting coil design used in the main bending magnets of the Relativistic Heavy Ion Collider recently completed at Brookhaven. The magnets for the LHC, to be built at Brookhaven, are described and results from the program to build two dual aperture prototypes are presented

  5. AC Josephson effect without superconductivity, and other effects of radio frequency quantum nanoelectronics

    Science.gov (United States)

    Waintal, Xavier; Gaury, Benoit; Weston, Joseph

    With single coherent electron sources and electronic interferometers now available in the lab, the time resolved dynamics of electrons can now be probed directly. I will discuss how a fast raise of voltage propagates inside an electronic interferometer and leads to an oscillating current of well controled frequency. This phenomena is the normal counterpart to the AC josephson effect. I will also briefly advertize our software for computing quantum transport properties, Kwant (http://kwant-project.org) and its time-dependent extension T-Kwant.

  6. Superconductivity

    International Nuclear Information System (INIS)

    Kakani, S.L.; Kakani, Shubhra

    2007-01-01

    The monograph provides readable introduction to the basics of superconductivity for beginners and experimentalists. For theorists, the monograph provides nice and brief description of the broad spectrum of experimental properties, theoretical concepts with all details, which theorists should learn, and provides a sound basis for students interested in studying superconducting theory at the microscopic level. Special chapter on the theory of high-temperature superconductivity in cuprates is devoted

  7. Superconducting properties of Zn and Al double-doped Mg1-x(Zn0.5Al0.5)xB2

    DEFF Research Database (Denmark)

    Xu, G.J.; Grivel, Jean-Claude; Abrahamsen, A.B.

    2004-01-01

    (XRD), ac susceptibility, magnetization and resistivity. The double doping leads to decreases in both the lattice parameters a and c, and the T-c decreases with increasing dopant content. A systematical comparison with Al doped- and Li, Al double doped MgB2 of structure, superconducting transition......A series of polycrystalline samples of Mg1-x(Zn0.5Al0.5)(x)B-2 (0less than or equal toxless than or equal to0.8) were prepared by solid state reaction method and their structure, superconducting transition temperature (T-c) and transport properties were investigated by means of X-ray diffraction...

  8. Increased Ac excision (iae): Arabidopsis thaliana mutations affecting Ac transposition

    International Nuclear Information System (INIS)

    Jarvis, P.; Belzile, F.; Page, T.; Dean, C.

    1997-01-01

    The maize transposable element Ac is highly active in the heterologous hosts tobacco and tomato, but shows very much reduced levels of activity in Arabidopsis. A mutagenesis experiment was undertaken with the aim of identifying Arabidopsis host factors responsible for the observed low levels of Ac activity. Seed from a line carrying a single copy of the Ac element inserted into the streptomycin phosphotransferase (SPT) reporter fusion, and which displayed typically low levels of Ac activity, were mutagenized using gamma rays. Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium. The mutations fall into two complementation groups, iae1 and iae2, are unlinked to the SPT::Ac locus and segregate in a Mendelian fashion. The iae1 mutation is recessive and the iae2 mutation is semi-dominant. The iae1 and iae2 mutants show 550- and 70-fold increases, respectively, in the average number of Ac excision sectors per cotyledon. The IAE1 locus maps to chromosome 2, whereas the SPT::Ac reporter maps to chromosome 3. A molecular study of Ac activity in the iae1 mutant confirmed the very high levels of Ac excision predicted using the phenotypic assay, but revealed only low levels of Ac re-insertion. Analyses of germinal transposition in the iae1 mutant demonstrated an average germinal excision frequency of 3% and a frequency of independent Ac re-insertions following germinal excision of 22%. The iae mutants represents a possible means of improving the efficiency of Ac/Ds transposon tagging systems in Arabidopsis, and will enable the dissection of host involvement in Ac transposition and the mechanisms employed for controlling transposable element activity

  9. Superconductivity for Large Scale Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    R. Fair; W. Stautner; M. Douglass; R. Rajput-Ghoshal; M. Moscinski; P. Riley; D. Wagner; J. Kim; S. Hou; F. Lopez; K. Haran; J. Bray; T. Laskaris; J. Rochford; R. Duckworth

    2012-10-12

    A conceptual design has been completed for a 10MW superconducting direct drive wind turbine generator employing low temperature superconductors for the field winding. Key technology building blocks from the GE Wind and GE Healthcare businesses have been transferred across to the design of this concept machine. Wherever possible, conventional technology and production techniques have been used in order to support the case for commercialization of such a machine. Appendices A and B provide further details of the layout of the machine and the complete specification table for the concept design. Phase 1 of the program has allowed us to understand the trade-offs between the various sub-systems of such a generator and its integration with a wind turbine. A Failure Modes and Effects Analysis (FMEA) and a Technology Readiness Level (TRL) analysis have been completed resulting in the identification of high risk components within the design. The design has been analyzed from a commercial and economic point of view and Cost of Energy (COE) calculations have been carried out with the potential to reduce COE by up to 18% when compared with a permanent magnet direct drive 5MW baseline machine, resulting in a potential COE of 0.075 $/kWh. Finally, a top-level commercialization plan has been proposed to enable this technology to be transitioned to full volume production. The main body of this report will present the design processes employed and the main findings and conclusions.

  10. PK-ISIS: a new superconducting ECR ion source at Pantechnik

    International Nuclear Information System (INIS)

    Villari, A.C.; Bieth, C.; Bougy, W.; Brionne, N.; Donzel, X.; Gaubert, G.; Leroy, R.; Sineau, A.; Tasset, O.; Vallerand, C.; Thuillier, T.

    2012-01-01

    The new ECR ion source PK-ISIS was recently commissioned at Pantechnik. Three superconducting coils generate the axial magnetic field configuration while the radial magnetic field is done with multi-layer permanent magnets. Special care was devoted in the design of the hexapolar structure, allowing a maximum magnetic field of 1.32 T at the wall of the 82 mm diameter plasma chamber. The three superconducting coils using Low Temperature Superconducting wires are cooled by a single double stage cryo-cooler (4.2 K). Cryogen-free technology is used, providing reliability, easy maintenance at low cost. The maximum installed RF power (18.0 GHz) is of 2 kW. Metallic beams can be produced with an oven (T max = 1400 C) installed with an angle of 5 degrees with respect to the source axis or a sputtering system, mounted in the axis of the source. The beam extraction system is constituted of three electrodes in accel-decel configuration. The new source of Pantechnik is conceived for reaching optimum performances at 18 GHz RF frequencies. PK-ISIS delivers 5 to 10 times more beam intensity than the original PK-DELIS and/or shifting the charge state distribution to higher values. PK-ISIS is built with Low Temperature Superconducting wire technology (LTS), but keeps the He-free concept, extremely important for a reliable and easy operation. The radial field circuit is permanent magnet made. Finally, PK-ISIS is also conceived for using in a High-Voltage platform with minor power consumption. The paper is followed by the slides of the presentation. (A.C.)

  11. A.c. susceptibility measurements in the presence of d.c. magnetic fields for Nd-Ba-Cu-O superconductors

    International Nuclear Information System (INIS)

    Watahiki, M.; Murakami, M.; Yoo, S.I.

    1997-01-01

    We report the temperature and magnetic field dependence of the complex a.c. susceptibility with bias d.c. magnetic fields for melt-processed Nd-Ba-Cu-O superconductor. The onset temperature (T onset ) of the real part of a.c. susceptibility shifted to a lower temperature with increasing d.c. magnetic field. The superconducting transition temperature (T c ) determined by d.c. magnetization measurements did not shift appreciably to a lower-temperature region with increasing d.c. magnetic field. The distinction between T onset and T c indicates that the a.c. susceptibility measurements detect the energy dissipation generated by the motion of flux lines. We have also measured flux profiles and found that there was no appreciable change in flux penetration below and above the peak field, which suggests that the peak effect in Nd-Ba-Cu-O is not due to the phase transition in the flux line lattice. (author)

  12. Thermal properties of a large-bore cryocooled 10 T superconducting magnet for a hybrid magnet

    International Nuclear Information System (INIS)

    Ishizuka, M.; Hamajima, T.; Itou, T.; Sakuraba, J.; Nishijima, G.; Awaji, S.; Watanabe, K.

    2010-01-01

    A cryocooled 10 T superconducting magnet with a 360 mm room temperature bore has been developed for a hybrid magnet. The superconducting magnet cooled by four Gifford-McMahon cryocoolers has been designed to generate a magnetic field of 10 T. Since superconducting wires composed of coils were subjected to large hoop stress over 150 MPa and Nb 3 Sn superconducting wires particularly showed a low mechanical strength due to those brittle property, Nb 3 Sn wires strengthened by NbTi-filaments were developed for the cryocooled superconducting magnet. We have already reported that the hybrid magnet could generate the resultant magnetic field of 27.5 T by adding 8.5 T from the superconducting magnet and 19 T from a water-cooled Bitter resistive magnet, after the water-cooled resistive magnet was inserted into the 360 mm room temperature bore of the cryocooled superconducting magnet. When the hybrid magnet generated the field of 27.5 T, it achieved the high magnetic-force field (B x ∂Bz/∂z) of 4500 T 2 /m, which was useful for magneto-science in high fields such as materials levitation research. In this paper, we particularly focus on the cause that the cryocooled superconducting magnet was limited to generate the designed magnetic field of 10 T in the hybrid magnet operation. As a result, it was found that there existed mainly two causes as the limitation of the magnetic field generation. One was a decrease of thermal conductive passes due to exfoliation from the coil bobbin of the cooling flange. The other was large AC loss due to both a thick Nb 3 Sn layer and its large diameter formed on Nb-barrier component in Nb 3 Sn wires.

  13. Low AC Loss in a 3 kA HTS Cable of the Dutch Project

    Science.gov (United States)

    Chevtchenko, Oleg; Zuijderduin, Roy; Smit, Johan; Willén, Dag; Lentge, Heidi; Thidemann, Carsten; Traeholt, Chresten; Melnik, Irina; Geschiere, Alex

    Requirements for a 6 km long high temperature superconducting (HTS) AC power cable of the Amsterdam project are: a cable has to fit in an annulus of 160 mm, with two cooling stations at the cable ends only. Existing solutions for HTS cables would lead to excessively high coolant pressure drop in the cable, potentially affecting public acceptance of the project. A way out would be to substantially reduce AC losses from 1 down to about 0.1 W/m per phase at rated current of 3 kArms, frequency of 50 Hz and temperature of 77 K. In this paper we discuss a strategy towards this ambitious goal, a concept design of the single phase cable 3 kA conductor made of YBCO tapes and present corresponding experimental and simulation data supporting the developed approach leading directly to this goal. HTS cable model was made that show a drastically reduced AC loss. The low loss was achieved by using appropriate pitch angles for two-layer cable conductor of relatively large diameter, by minimizing the gaps between the HTS tapes, and by using narrow HTS tapes that conform well to the roundness of the underlying former. AC loss of 0.12 W/m at 3 kArms was measured at a frequency of 60 Hz and at a temperature of 77 K.

  14. Design and analysis of the tooling upgrade for the production of the superconductive main dipole magnet prototypes of LHC

    CERN Document Server

    AUTHOR|(CDS)2093638

    Design and analysis of the tooling upgrade for the production of the superconductive main dipole magnet prototypes of LHC Master of Science Thesis, 110 pages, 12 Appendix pages September 2013 Major: Design of machines and systems Examiner: Professor Reijo Kouhia Keywords: CERN, LHC, High Luminosity LHC project, superconductive dipole magnet, welding press, Nb$_{3}$Sn, pre-stress, Ar-inert gas furnace This thesis work has been carried out as a contribution to the development program of superconductive magnets within the LHC High Luminosity study. The thesis provides an insight to the steps that need to be taken in order to produce a superconductive magnet mainly focusing on mechanical assembly. Tooling upgrade is necessary for the production of the superconductive dipole magnet prototypes in near future. Major attention is given by the introduction of the welding assembly in chapter three. The structural compression is given by the so called shell stress defined by the thermal shrinkage of the weld. The associ...

  15. Superconductivity

    International Nuclear Information System (INIS)

    Langone, J.

    1989-01-01

    This book explains the theoretical background of superconductivity. Includes discussion of electricity, material fabrication, maglev trains, the superconducting supercollider, and Japanese-US competition. The authors reports the latest discoveries

  16. The future machine with electrons of 15-30 GeV

    International Nuclear Information System (INIS)

    Tkatchenko, A.

    1992-01-01

    This article presents the project of european linear accelerator with a continuous beam of high energy electrons for the Nuclear Physics researches. Based on a superconducting linear accelerator crossed several times, this machine will be able to produce beams of 15 GeV in a first time, then 30 GeV, by increasing of accelerator cavity field without modifying the beam circulation system

  17. High-temperature superconductivity

    International Nuclear Information System (INIS)

    Ginzburg, V.L.

    1987-07-01

    After a short account of the history of experimental studies on superconductivity, the microscopic theory of superconductivity, the calculation of the control temperature and its possible maximum value are presented. An explanation of the mechanism of superconductivity in recently discovered superconducting metal oxide ceramics and the perspectives for the realization of new high-temperature superconducting materials are discussed. 56 refs, 2 figs, 3 tabs

  18. Superconducting accelerator technology

    International Nuclear Information System (INIS)

    Grunder, H.A.; Hartline, B.K.

    1986-01-01

    Modern and future accelerators for high energy and nuclear physics rely increasingly on superconducting components to achieve the required magnetic fields and accelerating fields. This paper presents a practical overview of the phenomenon of superconductivity, and describes the design issues and solutions associated with superconducting magnets and superconducting rf acceleration structures. Further development and application of superconducting components promises increased accelerator performance at reduced electric power cost

  19. MOEA based design of decentralized controllers for LFC of interconnected power systems with nonlinearities, AC-DC parallel tie-lines and SMES units

    International Nuclear Information System (INIS)

    Ganapathy, S.; Velusami, S.

    2010-01-01

    A new design of Multi-Objective Evolutionary Algorithm based decentralized controllers for load-frequency control of interconnected power systems with Governor Dead Band and Generation Rate Constraint nonlinearities, AC-DC parallel tie-lines and Superconducting Magnetic Energy Storage (SMES) units, is proposed in this paper. The HVDC link is used as system interconnection in parallel with AC tie-line to effectively damp the frequency oscillations of AC system while the SMES unit provides bulk energy storage and release, thereby achieving combined benefits. The proposed controller satisfies two main objectives, namely, minimum Integral Squared Error of the system output and maximum closed-loop stability of the system. Simulation studies are conducted on a two area interconnected power system with nonlinearities, AC-DC tie-lines and SMES units. Results indicate that the proposed controller improves the transient responses and guarantees the closed-loop stability of the overall system even in the presence of system nonlinearities and with parameter changes.

  20. Superconductivity under high pressure in the binary compound CaLi2

    Science.gov (United States)

    Debessai, M.; Matsuoka, T.; Hamlin, J. J.; Gangopadhyay, A. K.; Schilling, J. S.; Shimizu, K.; Ohishi, Y.

    2008-12-01

    Feng predicted for CaLi2 highly anomalous properties with possible superconductivity under very high pressures, including for the hcp polymorph a significant lattice bifurcation at pressures above 47 GPa. More recently, however, Feng suggested that for pressures exceeding 20 GPa CaLi2 may dissociate into elemental Ca and Li. Here we present for hcp CaLi2 measurements of the electrical resistivity and ac susceptibility to low temperatures under pressures as high as 81 GPa. Pressure-induced superconductivity is observed in the pressure range of 11-81 GPa, with Tc reaching values as high as 13 K. X-ray diffraction studies to 54 GPa at 150 K reveal that hcp CaLi2 undergoes a structural phase transition above 23 GPa to orthorhombic but does not dissociate into elemental Ca and Li. In the hcp phase a fit of the equation of state with the Murnaghan equation yields the bulk modulus Bo=15(2)GPa and dBo/dP=3.2(6) .

  1. Superconductivity and future accelerators

    International Nuclear Information System (INIS)

    Danby, G.T.; Jackson, J.W.

    1963-01-01

    For 50 years particle accelerators employing accelerating cavities and deflecting magnets have been developed at a prodigious rate. New accelerator concepts and hardware ensembles have yielded great improvements in performance and GeV/$. The great idea for collective acceleration resulting from intense auxiliary charged-particle beams or laser light may or may not be just around the corner. In its absence, superconductivity (SC) applied both to rf cavities and to magnets opened up the potential for very large accelerators without excessive energy consumption and with other economies, even with the cw operation desirable for colliding beams. HEP has aggressively pioneered this new technology: the Fermilab single ring 1 TeV accelerator - 2 TeV collider is near the testing stage. Brookhaven National Laboratory's high luminosity pp 2 ring 800 GeV CBA collider is well into construction. Other types of superconducting projects are in the planning stage with much background R and D accomplished. The next generation of hadron colliders under discussion involves perhaps a 20 TeV ring (or rings) with 40 TeV CM energy. This is a very large machine: even if the highest practical field B approx. 10T is used, the radius is 10x that of the Fermilab accelerator. An extreme effort to get maximum GeV/$ may be crucial even for serious consideration of funding

  2. Performance of the Superconducting Corrector Magnet Circuits during the Commissioning of the LHC

    CERN Document Server

    Venturini-Delsolaro, W; Ballarino, A; Bellesia, B; Bordry, Frederick; Cantone, A; Casas Lino, M; Castaneda Serra, A; Castillo Trello, C; Catalan-Lasheras, N; Charifoulline, Z; Charrondiere, C; Dahlerup-Petersen, K; D'Angelo, G; Denz, R; Fehér, S; Flora, R; Gruwé, M; Kain, V; Karppinen, M; Khomenko, B; Kirby, G; MacPherson, A; Marqueta Barbero, A; Mess, K H; Modena, M; Mompo, R; Montabonnet, V; le Naour, S; Nisbet, D; Parma, V; Pojer, M; Ponce, L; Raimondo, A; Redaelli, S; Remondino, V; Reymond, H; de Rijk, G; Rijllart, A; Romera Ramirez, I; Saban, R; Sanfilippo, S; Schirm, K; Schmidt, R; Siemko, A; Solfaroli Camillocci, M; Thurel, Y; Thiesen, H; Vergara Fernandez, A; Verweij, A; Wolf, R; Zerlauth, M

    2008-01-01

    The LHC is a complex machine requiring more than 7400 superconducting corrector magnets distributed along a circumference of 26.7 km. These magnets are powered in 1446 different electrical circuits at currents ranging from 60 A up to 600 A. Among the corrector circuits the 600 A corrector magnets form the most diverse and differentiated group. All together, about 60000 high current connections had to be made. A fault in a circuit or one of the superconducting connections would have severe consequences for the accelerator operation. All magnets are wound from various types of Nb-Ti superconducting strands, and many contain parallel protection resistors to by-pass the current still flowing in the other magnets of the same circuit when they quench. In this paper the performance of these magnet circuits is presented, focussing on the quench behaviour of the magnets. Quench detection and the performance of the electrical interconnects will be dealt with. The results as measured on the entire circuits are compar...

  3. Machine vision and mechatronics in practice

    CERN Document Server

    Brett, Peter

    2015-01-01

    The contributions for this book have been gathered over several years from conferences held in the series of Mechatronics and Machine Vision in Practice, the latest of which was held in Ankara, Turkey. The essential aspect is that they concern practical applications rather than the derivation of mere theory, though simulations and visualization are important components. The topics range from mining, with its heavy engineering, to the delicate machining of holes in the human skull or robots for surgery on human flesh. Mobile robots continue to be a hot topic, both from the need for navigation and for the task of stabilization of unmanned aerial vehicles. The swinging of a spray rig is damped, while machine vision is used for the control of heating in an asphalt-laying machine.  Manipulators are featured, both for general tasks and in the form of grasping fingers. A robot arm is proposed for adding to the mobility scooter of the elderly. Can EEG signals be a means to control a robot? Can face recognition be ac...

  4. Superconducting technology

    International Nuclear Information System (INIS)

    2010-01-01

    Superconductivity has a long history of about 100 years. Over the past 50 years, progress in superconducting materials has been mainly in metallic superconductors, such as Nb, Nb-Ti and Nb 3 Sn, resulting in the creation of various application fields based on the superconducting technologies. High-T c superconductors, the first of which was discovered in 1986, have been changing the future vision of superconducting technology through the development of new application fields such as power cables. On basis of these trends, future prospects of superconductor technology up to 2040 are discussed. In this article from the viewpoints of material development and the applications of superconducting wires and electronic devices. (author)

  5. Remarkable effects of disorder on superconductivity of single atomic layers of lead on silicon

    Science.gov (United States)

    Brun, Christophe

    2015-03-01

    It is well known that conventional superconductivity is very robust against non-magnetic disorder. Nevertheless for thin and ultrathin films the structural properties play a major role in determining the superconducting properties, through a subtle interplay between disorder and Coulomb interactions. Unexpectedly, in 2010 superconductivity was discovered in single atomic layers of lead and indium grown on silicon substrate using scanning tunneling spectroscopy and confirmed later on by macroscopic transport measurements. Such well-controlled and tunable crystalline monolayers are ideal systems for studying the influence of various kinds of structural defects on the superconducting properties at the atomic and mesoscopic scale. In particular, Pb monolayers offer the opportunity of probing new effects of disorder because not only superconductivity is 2D but also the electronic wave functions are 2D. Our study of two Pb monolayers of different crystal structures by very-low temperature STM (300 mK) under magnetic field reveals unexpected results involving new spatial spectroscopic variations. Our results show that although the sheet resistance of the Pb monolayers is much below the resistance quantum, strong non-BCS corrections appear leading to peak heights fluctuations in the dI/dV tunneling spectra at a spatial scale much smaller than the superconducting coherence length. Furthermore, strong local evidence of the signature of Rashba effect on the superconductivity of the Pb/Si(111) monolayer is revealed through filling of in gap states and local spatial variations of this filling. Finally the nature of vortices in a monolayer is found to be very sensitive to the properties of step edges areas. This work was supported by University Pierre et Marie Curie UPMC `Emergence' project, French ANR Project `ElectroVortex,' ANR-QuDec and Templeton Foundation (40381), ARO (W911NF-13-1-0431) and CNRS PICS funds. Partial funding by US-DOE Grant DE-AC02-07CH1.

  6. High Tc superconducting energy storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Werfel, Frank [Adelwitz Technologiezentrum GmbH (ATZ), Arzberg-Adelwitz (Germany)

    2012-07-01

    Electric energy is basic to heat and light our homes, to power our businesses and to transport people and goods. Powerful storage techniques like SMES, Flywheel, Super Capacitor, and Redox - Flow batteries are needed to increase the overall efficiency, stability and quality of electrical grids. High-Tc superconductors (HTS) possess superior physical and technical properties and can contribute in reducing the dissipation and losses in electric machines as motors and generators, in electric grids and transportation. The renewable energy sources as solar, wind energy and biomass will require energy storage systems even more as a key technology. We survey the physics and the technology status of superconducting flywheel energy storage (FESS) and magnetic energy storage systems (SMES) for their potential of large-scale commercialization. We report about a 10 kWh / 250 kW flywheel with magnetic stabilization of the rotor. The progress of HTS conductor science and technological engineering are basic for larger SMES developments. The performance of superconducting storage systems is reviewed and compared. We conclude that a broad range of intensive research and development in energy storage is urgently needed to produce technological options that can allow both climate stabilization and economic development.

  7. AC Initiation System.

    Science.gov (United States)

    An ac initiation system is described which uses three ac transmission signals interlocked for safety by frequency, phase, and power discrimination...The ac initiation system is pre-armed by the application of two ac signals have the proper phases, and activates a load when an ac power signal of the proper frequency and power level is applied. (Author)

  8. On the origin of the double superconducting transition in overdoped YBa2Cu3O x

    International Nuclear Information System (INIS)

    Lortz, R.; Tomita, T.; Wang, Y.; Junod, A.; Schilling, J.S.; Masui, T.; Tajima, S.

    2006-01-01

    The superconducting transition in a single overdoped, detwinned YBa 2 Cu 3 O x (YBCO) crystal is studied using four different probes. Whereas the AC and DC magnetic susceptibilities find a dominant transition at 88 K with a smaller effect near 92 K, the specific heat and electrical resistivity reveal only a single transition at 88 K and 92 K, respectively. Under hydrostatic pressures to 0.60 GPa these two transitions shift in opposite directions, their separation increasing. The present experiments clearly show that the bulk transition lies at 88 K and originates from fully oxygenated YBCO; the 92 K transition likely arises from filamentary superconductivity in a minority optimally doped phase (<1%) of YBCO located at or near the crystal surface

  9. Winding machine and tools for the ISR Superconducting Quadrupole Prototype

    CERN Multimedia

    1975-01-01

    The picture shows the rotating and rocking winding machine with its "light" clamping system to keep the conductor turns in place during winding.At the back left one sees the conductor spool with its electromagnetic brake and the "heavy" clamping system used during curing. See also 7510217X, 7702690X.

  10. Superconductivity

    CERN Document Server

    Ketterson, John B

    2008-01-01

    Conceived as the definitive reference in a classic and important field of modern physics, this extensive and comprehensive handbook systematically reviews the basic physics, theory and recent advances in the field of superconductivity. Leading researchers, including Nobel laureates, describe the state-of-the-art in conventional and unconventional superconductors at a particularly opportune time, as new experimental techniques and field-theoretical methods have emerged. In addition to full-coverage of novel materials and underlying mechanisms, the handbook reflects continued intense research into electron-phone based superconductivity. Considerable attention is devoted to high-Tc superconductivity, novel superconductivity, including triplet pairing in the ruthenates, novel superconductors, such as heavy-Fermion metals and organic materials, and also granular superconductors. What’s more, several contributions address superconductors with impurities and nanostructured superconductors. Important new results on...

  11. Pareto optimal design of sectored toroidal superconducting magnet for SMES

    Energy Technology Data Exchange (ETDEWEB)

    Bhunia, Uttam, E-mail: ubhunia@vecc.gov.in; Saha, Subimal; Chakrabarti, Alok

    2014-10-15

    Highlights: • The optimization approach minimizes both the magnet size and necessary cable length of a sectored toroidal SMES unit. • Design approach is suitable for low temperature superconducting cable suitable for medium size SMES unit. • It investigates coil parameters with respect to practical engineering aspects. - Abstract: A novel multi-objective optimization design approach for sectored toroidal superconducting magnetic energy storage coil has been developed considering the practical engineering constraints. The objectives include the minimization of necessary superconductor length and torus overall size or volume, which determines a significant part of cost towards realization of SMES. The best trade-off between the necessary conductor length for winding and magnet overall size is achieved in the Pareto-optimal solutions, the compact magnet size leads to increase in required superconducting cable length or vice versa The final choice among Pareto optimal configurations can be done in relation to other issues such as AC loss during transient operation, stray magnetic field at outside the coil assembly, and available discharge period, which is not considered in the optimization process. The proposed design approach is adapted for a 4.5 MJ/1 MW SMES system using low temperature niobium–titanium based Rutherford type cable. Furthermore, the validity of the representative Pareto solutions is confirmed by finite-element analysis (FEA) with a reasonably acceptable accuracy.

  12. Pareto optimal design of sectored toroidal superconducting magnet for SMES

    International Nuclear Information System (INIS)

    Bhunia, Uttam; Saha, Subimal; Chakrabarti, Alok

    2014-01-01

    Highlights: • The optimization approach minimizes both the magnet size and necessary cable length of a sectored toroidal SMES unit. • Design approach is suitable for low temperature superconducting cable suitable for medium size SMES unit. • It investigates coil parameters with respect to practical engineering aspects. - Abstract: A novel multi-objective optimization design approach for sectored toroidal superconducting magnetic energy storage coil has been developed considering the practical engineering constraints. The objectives include the minimization of necessary superconductor length and torus overall size or volume, which determines a significant part of cost towards realization of SMES. The best trade-off between the necessary conductor length for winding and magnet overall size is achieved in the Pareto-optimal solutions, the compact magnet size leads to increase in required superconducting cable length or vice versa The final choice among Pareto optimal configurations can be done in relation to other issues such as AC loss during transient operation, stray magnetic field at outside the coil assembly, and available discharge period, which is not considered in the optimization process. The proposed design approach is adapted for a 4.5 MJ/1 MW SMES system using low temperature niobium–titanium based Rutherford type cable. Furthermore, the validity of the representative Pareto solutions is confirmed by finite-element analysis (FEA) with a reasonably acceptable accuracy

  13. The DARPA compact Superconducting X-Ray Lithography Source features

    International Nuclear Information System (INIS)

    Heese, R.; Kalsi, S.; Leung, E.

    1991-01-01

    Under DARPA sponsorship, a compact Superconducting X-Ray Lithography Source (SXLS) is being designed and built by the Brookhaven National Laboratory (BNL) with industry participation from Grumman Corporation and General Dynamics. This source is optimized for lithography work for sub-micron high density computer chips, and is about the size of a billiard table (1.5 m x 4.0 m). The machine has a racetrack configuration with two 180 degree bending magnets being designed and built by General Dynamics under a subcontract with Grumman Corporation. The machine will have 18 photon ports which would deliver light peaked at a wave length of 10 Angstroms. Grumman is commercializing the SXLS device and plans to book orders for delivery of industrialized SXLS (ISXLS) versions in 1995. This paper will describe the major features of this device. The commercial machine will be equipped with a fully automated user-friendly control systems, major features of which are already working on a compact warm dipole ring at BNL. This ring has normal dipole magnets with dimensions identical to the SXLS device, and has been successfully commissioned

  14. On test results of the superconducting magnetic energy storage (SMES) system in Ariuragawa Power Station

    International Nuclear Information System (INIS)

    Katahira, Osamu; Fukui, Fumihiko; Karano, Koichi; Irie, Fujio; Takeo, Masakatsu; Okada, Hidehiko; Shimojo, Toshikazu.

    1991-01-01

    SMES system is that for storing electric energy in the form of magnetic energy by flowing DC current through a superconducting coil by utilizing the characteristics of its superconductivity. It comprises a superconducting coil for storing energy, an AC-DC converter, the cooling system for maintaining extremely low temperature and so on. The features of SMES are the high efficiency of storing electric energy (more than 90 % in the large scale system), the fast response to store and release electric power, and effective power and reactive power can be independently and arbitrarily controlled. It is expected that SMES can be applied to the stabilization of electric power system, the adjustment of system voltage, the adjustment of varying load and so on. In order to verify the results of the laboratory research in actual power system, the system test was carried out in Ariuragawa Power Station on November 20-22, 1990. The outline of the test, the method of controlling SMES, the test results and the examination of the results are reported. (K.I.)

  15. Multi-cell superconducting structures for high energy e+ e- colliders and free electron laser linacs

    CERN Document Server

    Sekutowicz, J

    2008-01-01

    This volume, which is the first in the EuCARD Editorial Series on “Accelerator Science and Technology”, is closely combined with the most advanced particle accelerators – based on Superconducting Radio Frequency (SRF) technology. In general, SRF research includes following areas: high gradient cavities, cavity prototyping, thin film technologies, large grain and mono-crystalline niobium and niobium alloys, quenching effects in superconducting cavities, SRF injectors, photo-cathodes, beam dynamics, quality of electron beams, cryogenics, high power RF sources, low level RF controls, tuners, RF power coupling to cavities, RF test infrastructures, etc. The monograph focuses on TESLA structures used in FLASH machine and planned for XFEL and ILC experiments.

  16. Superconductivity revisited

    CERN Document Server

    Dougherty, Ralph

    2013-01-01

    While the macroscopic phenomenon of superconductivity is well known and in practical use worldwide in many industries, including MRIs in medical diagnostics, the current theoretical paradigm for superconductivity (BCS theory) suffers from a number of limitations, not the least of which is an adequate explanation of high temperature superconductivity. This book reviews the current theory and its limitations and suggests new ideas and approaches in addressing these issues. The central objective of the book is to develop a new, coherent, understandable theory of superconductivity directly based on molecular quantum mechanics.

  17. Machine Induced Experimental Background Conditions in the LHC

    CERN Document Server

    Levinsen, Yngve Inntjore; Stapnes, Steinar

    2012-09-19

    The Large Hadron Collider set a new energy record for particle accelerators in late 2009, breaking the previous record held by Tevatron of 2 TeV collision energy. The LHC today operates at a collision energy of 7 TeV. With higher beam energy and intensity, measures have to be taken to ensure optimal experimental conditions and safety of the machine and detectors. Machine induced experimental background can severely reduce the quality of experimental triggers and track reconstruction. In a worst case, the radiation levels can be damaging for some of the subdetectors. The LHC is a particular challenge in this regard due to the vastly different operating conditions of the different experiments. The nominal luminosity varies by four orders of magnitude. The unprecedented stored beam energy and the amount of superconducting elements can make it challenging to protect the accelerator itself as well. In this work we have simulated and measured the machine induced background originating from various sources: the beam...

  18. High field superconducting magnets

    Science.gov (United States)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  19. Niobium superconducting rf cavity fabrication by electrohydraulic forming

    Science.gov (United States)

    Cantergiani, E.; Atieh, S.; Léaux, F.; Perez Fontenla, A. T.; Prunet, S.; Dufay-Chanat, L.; Koettig, T.; Bertinelli, F.; Capatina, O.; Favre, G.; Gerigk, F.; Jeanson, A. C.; Fuzeau, J.; Avrillaud, G.; Alleman, D.; Bonafe, J.; Marty, P.

    2016-11-01

    Superconducting rf (SRF) cavities are traditionally fabricated from superconducting material sheets or made of copper coated with superconducting material, followed by trim machining and electron-beam welding. An alternative technique to traditional shaping methods, such as deep-drawing and spinning, is electrohydraulic forming (EHF). In EHF, half-cells are obtained through ultrahigh-speed deformation of blank sheets, using shockwaves induced in water by a pulsed electrical discharge. With respect to traditional methods, such a highly dynamic process can yield interesting results in terms of effectiveness, repeatability, final shape precision, higher formability, and reduced springback. In this paper, the first results of EHF on high purity niobium are presented and discussed. The simulations performed in order to master the multiphysics phenomena of EHF and to adjust its process parameters are presented. The microstructures of niobium half-cells produced by EHF and by spinning have been compared in terms of damage created in the material during the forming operation. The damage was assessed through hardness measurements, residual resistivity ratio (RRR) measurements, and electron backscattered diffraction analyses. It was found that EHF does not worsen the damage of the material during forming and instead, some areas of the half-cell have shown lower damage compared to spinning. Moreover, EHF is particularly advantageous to reduce the forming time, preserve roughness, and to meet the final required shape accuracy.

  20. Study on ac losses of HTS coil carrying ac transport current

    International Nuclear Information System (INIS)

    Dai Taozhen; Tang Yuejin; Li Jingdong; Zhou Yusheng; Cheng Shijie; Pan Yuan

    2005-01-01

    Ac loss has an important influence on the thermal performances of HTS coil. It is necessary to quantify ac loss to ascertain its impact on coil stability and for sizing the coil refrigeration system. In this paper, we analyzed in detail the ac loss components, hysteresis loss, eddy loss and flux flow loss in the pancake HTS coil carrying ac transport current by finite element method. We also investigated the distribution of the ac losses in the coil to study the effects of magnetic field distribution on ac losses

  1. Electrical machines with Matlab

    CERN Document Server

    Gonen, Turan

    2011-01-01

    Basic ConceptsDistribution SystemImpact of Dispersed Storage and GenerationBrief Overview of Basic Electrical MachinesReal and Reactive Powers in Single-Phase AC CircuitsThree-Phase CircuitsThree-Phase SystemsUnbalanced Three-Phase LoadsMeasurement of Average Power in Three-Phase CircuitsPower Factor CorrectionMagnetic CircuitsMagnetic Field of Current-Carrying ConductorsAmpère's Magnetic Circuital LawMagnetic CircuitsMagnetic Circuit with Air GapBrief Review of FerromagnetismMagnetic Core LossesHow to Determine Flux for a Given MMFPermanent MagnetsTransformersTransformer ConstructionBrief Rev

  2. Pareto optimal design of sectored toroidal superconducting magnet for SMES

    Science.gov (United States)

    Bhunia, Uttam; Saha, Subimal; Chakrabarti, Alok

    2014-10-01

    A novel multi-objective optimization design approach for sectored toroidal superconducting magnetic energy storage coil has been developed considering the practical engineering constraints. The objectives include the minimization of necessary superconductor length and torus overall size or volume, which determines a significant part of cost towards realization of SMES. The best trade-off between the necessary conductor length for winding and magnet overall size is achieved in the Pareto-optimal solutions, the compact magnet size leads to increase in required superconducting cable length or vice versa The final choice among Pareto optimal configurations can be done in relation to other issues such as AC loss during transient operation, stray magnetic field at outside the coil assembly, and available discharge period, which is not considered in the optimization process. The proposed design approach is adapted for a 4.5 MJ/1 MW SMES system using low temperature niobium-titanium based Rutherford type cable. Furthermore, the validity of the representative Pareto solutions is confirmed by finite-element analysis (FEA) with a reasonably acceptable accuracy.

  3. Multi-phase AC/AC step-down converter for distribution systems

    Science.gov (United States)

    Aeloiza, Eddy C.; Burgos, Rolando P.

    2017-10-25

    A step-down AC/AC converter for use in an electric distribution system includes at least one chopper circuit for each one of a plurality of phases of the AC power, each chopper circuit including a four-quadrant switch coupled in series between primary and secondary sides of the chopper circuit and a current-bidirectional two-quadrant switch coupled between the secondary side of the chopper circuit and a common node. Each current-bidirectional two-quadrant switch is oriented in the same direction, with respect to the secondary side of the corresponding chopper circuit and the common node. The converter further includes a control circuit configured to pulse-width-modulate control inputs of the switches, to convert a first multiphase AC voltage at the primary sides of the chopper circuits to a second multiphase AC voltage at the secondary sides of the chopper circuits, the second multiphase AC voltage being lower in voltage than the first multiphase AC voltage.

  4. 1999 Review of superconducting dipole and quadrupole magnets for particle accelerators

    International Nuclear Information System (INIS)

    Devred, A.

    1999-12-01

    The quest for elementary particles has promoted the development of particle accelerators producing beams of increasingly higher energies. In a synchrotron-type accelerator, the particle energy is directly proportional to the product of the machine's radius times the bending magnets' field strength. Present proton experiments at the TeV scale require facilities with circumferences ranging from a few to tens of kilometers and relying on a large number (several hundreds to several thousands) of high field dipole magnets and high field gradient quadrupole magnets. These electro-magnets use high current density, low critical temperature superconducting cables and are cooled down at liquid helium temperature. They are among the most costly and the most challenging components of the machine. After explaining what are the various types of accelerator magnets and why they are needed (section 1), we present a brief history of large superconducting particle accelerators, and we detail ongoing superconducting accelerator magnet R and D programs around the world (Section 2). Then, we review the superconducting materials that are available at industrial scale (chiefly, NbTi and Nb3Sn), and we describe the manufacturing of NbTi wires and cables (section 3). We also present the difficulties of processing and insulating Nb3Sn conductors which, so far, have limited the use of this material in spite of its superior performances. We continue by presenting the complex formalism used to represent two-dimensional fields (section 4), and we discuss the two-dimensional current distributions that are the most appropriate for generating pure dipole and pure quadrupole fields (section 5). We explain how these ideal distributions can be approximated by so-called cosθ and cos 2 θ coil designs and we describe the difficulties of realizing coil ends. Next, we present the mechanical design concepts that have been developed to restrain magnet coils and to ensure proper conductor positioning

  5. 1999 Review of superconducting dipole and quadrupole magnets for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Devred, A. [CEA/Saclay, Dept. d' Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l' Instrumentation Associee (DAPNIA), 91 - Gif-sur-Yvette (France); CERN, Conseil Europeen pour la recherche nucleaire, Laboratoire europeen pour la physique des particules Geneve (Switzerland)

    1999-12-01

    The quest for elementary particles has promoted the development of particle accelerators producing beams of increasingly higher energies. In a synchrotron-type accelerator, the particle energy is directly proportional to the product of the machine's radius times the bending magnets' field strength. Present proton experiments at the TeV scale require facilities with circumferences ranging from a few to tens of kilometers and relying on a large number (several hundreds to several thousands) of high field dipole magnets and high field gradient quadrupole magnets. These electro-magnets use high current density, low critical temperature superconducting cables and are cooled down at liquid helium temperature. They are among the most costly and the most challenging components of the machine. After explaining what are the various types of accelerator magnets and why they are needed (section 1), we present a brief history of large superconducting particle accelerators, and we detail ongoing superconducting accelerator magnet R and D programs around the world (Section 2). Then, we review the superconducting materials that are available at industrial scale (chiefly, NbTi and Nb3Sn), and we describe the manufacturing of NbTi wires and cables (section 3). We also present the difficulties of processing and insulating Nb3Sn conductors which, so far, have limited the use of this material in spite of its superior performances. We continue by presenting the complex formalism used to represent two-dimensional fields (section 4), and we discuss the two-dimensional current distributions that are the most appropriate for generating pure dipole and pure quadrupole fields (section 5). We explain how these ideal distributions can be approximated by so-called cos{theta} and cos{sup 2}{theta} coil designs and we describe the difficulties of realizing coil ends. Next, we present the mechanical design concepts that have been developed to restrain magnet coils and to ensure proper

  6. Electron-tunneling observation of localized excited states in superconducting manganese-doped lead

    International Nuclear Information System (INIS)

    Tsang, J.; Ginsberg, D.M.

    1980-01-01

    We have made electron-tunneling measurements on a dilute, superconducting lead-manganese alloy. A well-defined structure was observed in the ac-conductance--voltage curves, indicating excited states within the BCS energy gap. These states were partially accounted for by Shiba theory when spin-dependent s-, p-, and d-wave scattering were included. The phase shifts used in doing that were the results of band calculations. The experimental data also show the existence of a broad background density of states in the energy gap, which cannot be accounted for by the theory

  7. The filled skutterudite PrOs4Sb12: superconductivity and correlations

    International Nuclear Information System (INIS)

    Measson, M.A.

    2005-12-01

    The filled skutterudite PrOs 4 Sb 12 is the first Pr-based heavy fermion superconductor. This thesis addresses several important open questions including the determination of the quasi-particle mass renormalisation, the nature and mechanism of superconductivity, and the intrinsic or extrinsic nature of the double superconducting transition seen in the specific heat. A fit of the specific heat with magnetic interactions between the ions Pr is proposed. We extract from it an electronic term of between 300-750 mJ/K 2 .mol(Pr). Analysis of the specific heat jump provides evidence that heavy carriers are involved in Cooper pairing and that superconductivity is strongly coupled. Extensive characterizations by specific heat, resistivity, susceptibility measurements show that a double transition appears in the best samples. Nevertheless we bring the first serious doubts on the intrinsic nature of the double transition, because we have found samples with a single sharp transition at Tc2 and because the ratio of the two specific heat jumps shows strong dispersion among the samples. Furthermore we have measured the superconducting phase diagrams with an A.C. specific heat technique under magnetic field and under pressure up to 4.2 GPa, and we show that the two transitions, Tc1 and Tc2, exhibit similar behaviours with magnetic field and pressure. We find a strong change in the pressure dependence of Tc's above 2 GPa which might be related to a change in the nature of the superconductivity under pressure (at least partially mediated by fluctuations and only by phonons at respectively low and high pressure) which may be linked to the increase of the crystal field gap of the Pr ions. Analysis of the upper critical field shows the presence of at least two superconducting bands and concludes to a singlet nature of the pairing. A strong distortion of the flux-line lattice, which is constant with temperature and field, is obtained by small angle neutron scattering measurement

  8. Study on the origin of pressure-induced superconductivity of Cs3C60

    International Nuclear Information System (INIS)

    Fujiki, S.; Kubozono, Y.; Takabayashi, Y.; Kashino, S.; Kobayashi, M.; Ishii, K.; Suematsu, H.

    2001-01-01

    Physical properties of bco phase of Cs 3+α C 60 (α=0.0-1.0) and A15 phase of Cs 3 C 60 are studied by X-ray diffraction, ESR, AC susceptibility, resistivity and Raman. The ESR of Cs 300(6) C 60 showed a broad peak of ∼380 G due to conduction electron, while no broad peak was observed in the ESR of bco Cs 3+α C 60 (α≠0.0) and A15 phase. This shows that only bco phase of Cs 3 C 60 is metallic. The AC susceptibility of bco phase of Cs 3.2(3) C 60 and Cs 3.5(1) C 60 showed no superconducting transition above 1.3 K even under high pressure, and the resistivity was 0.52 Ω cm for both samples

  9. Design and operating experience of an ac-dc power converter for a superconducting magnetic energy storage unit

    International Nuclear Information System (INIS)

    Boenig, H.J.; Nielsen, R.G.; Sueker, K.H.

    1984-01-01

    The design philosophy and the operating behavior of a 5.5 kA, +-2.5 kV converter, being the electrical interface between a high voltage transmission system and a 30 MJ superconducting coil, are documented in this paper. Converter short circuit tests, load tests under various control conditions, dc breaker tests for magnet current interruption, and converter failure modes are described

  10. The operator view of the Superconducting Cyclotron at LNS Catania

    International Nuclear Information System (INIS)

    Giove, D.; Cuttone, G.; Rovelli, A.

    1992-01-01

    The upper level of a distributed control system designed for the Superconducting Cyclotron (SC), will be discussed. In particular, we will present a detailed description of the operator view of this accelerator along with the tools for I/O points management, data representations, data archiving and retrieval. A dedicated program, developed by us, working under X-Window will be described as a starting point for a new man-machine interface approach in small laboratories opposed to the first industrial available packages. (author)

  11. Reliability of the quench protection system for the LHC superconducting elements

    International Nuclear Information System (INIS)

    Vergara Fernandez, A.; Rodriguez-Mateos, F.

    2004-01-01

    The Quench Protection System (QPS) is the sole system in the Large Hadron Collider machine monitoring the signals from the superconducting elements (bus bars, current leads, magnets) which form the cold part of the electrical circuits. The basic functions to be accomplished by the QPS during the machine operation will be briefly presented. With more than 4000 internal trigger channels (quench detectors and others), the final QPS design is the result of an optimised balance between on-demand availability and false quench reliability. The built-in redundancy for the different equipment will be presented, focusing on the calculated, expected number of missed quenches and false quenches. Maintenance strategies in order to improve the performance over the years of operation will be addressed

  12. Reliability of the quench protection system for the LHC superconducting elements

    Science.gov (United States)

    Vergara Fernández, A.; Rodríguez-Mateos, F.

    2004-06-01

    The Quench Protection System (QPS) is the sole system in the Large Hadron Collider machine monitoring the signals from the superconducting elements (bus bars, current leads, magnets) which form the cold part of the electrical circuits. The basic functions to be accomplished by the QPS during the machine operation will be briefly presented. With more than 4000 internal trigger channels (quench detectors and others), the final QPS design is the result of an optimised balance between on-demand availability and false quench reliability. The built-in redundancy for the different equipment will be presented, focusing on the calculated, expected number of missed quenches and false quenches. Maintenance strategies in order to improve the performance over the years of operation will be addressed.

  13. Superconductivity in Medicine

    Science.gov (United States)

    Alonso, Jose R.; Antaya, Timothy A.

    2012-01-01

    Superconductivity is playing an increasingly important role in advanced medical technologies. Compact superconducting cyclotrons are emerging as powerful tools for external beam therapy with protons and carbon ions, and offer advantages of cost and size reduction in isotope production as well. Superconducting magnets in isocentric gantries reduce their size and weight to practical proportions. In diagnostic imaging, superconducting magnets have been crucial for the successful clinical implementation of magnetic resonance imaging. This article introduces each of those areas and describes the role which superconductivity is playing in them.

  14. Topology Optimization of a High-Temperature Superconducting Field Winding of a Synchronous Machine

    DEFF Research Database (Denmark)

    Pozzi, Matias; Mijatovic, Nenad; Jensen, Bogi Bech

    2013-01-01

    This paper presents topology optimization (TO) of the high-temperature superconductor (HTS) field winding of an HTS synchronous machine. The TO problem is defined in order to find the minimum HTS material usage for a given HTS synchronous machine design. Optimization is performed using a modified...... genetic algorithm with local optimization search based on on/off sensitivity analysis. The results show an optimal HTS coil distribution, achieving compact designs with a maximum of approximately 22% of the available space for the field winding occupied with HTS tape. In addition, this paper describes...... potential HTS savings, which could be achieved using multiple power supplies for the excitation of the machine. Using the TO approach combined with two excitation currents, an additional HTS saving of 9.1% can be achieved....

  15. Inkjet printing of multifilamentary YBCO for low AC loss coated conductors

    International Nuclear Information System (INIS)

    Hopkins, S C; Joseph, D; Mitchell-Williams, T B; Glowacki, B A; Calleja, A; Vlad, V R; Vilardell, M; Ricart, S; Granados, X; Puig, T; Obradors, X; Usoskin, A; Falter, M; Bäcker, M

    2014-01-01

    Considerable progress has been made with the development of REBCO coated conductors in recent years, and high performance conductors are available commercially. For many applications, however, the cost remains prohibitive, and AC losses discourage their selection for higher frequency applications. Chemical solution deposition (CSD) methods are attractive for low-cost, scalable preparation of buffer and superconductor layers, and in many respects inkjet printing is the method of choice, permitting non-contact deposition with minimal materials wastage and excellent control of coating thickness. Highly textured coatings of YBCO and Gd-doped CeO 2 have previously been reported on buffered metal substrates. Inkjet printing also introduces the possibility of patterning - directly depositing two and three dimensional structures without subtractive processing - offering a low-cost route to coated conductors with reduced AC losses. In this contribution, the inkjet deposition of superconducting YBCO tracks is reported on industrially relevant buffered metal substrates both by direct printing and an inverse patterning approach. In the latter approach, ceria tracks were printed reported, which are a candidate both for resistive filament spacers and buffer layers. TFA-based precursor solutions have been printed on SS/ABAD-YSZ/CeO 2 and Ni-W/LZO/CeO 2 RABiTS substrates, and the resulting multifilamentary samples characterised by microscopy and scanning Hall probe measurements. The prospects for future inkjet-printed low AC loss coated conductors are discussed, including control of interfilamentary resistivity and bridging, transposed filamentary structures and stabilisation material.

  16. Wasted Heat Engine Utilization in Central AC Condenser Type Water Chiller for Economical Energy Water Heaters

    Directory of Open Access Journals (Sweden)

    I Made Rasta

    2012-11-01

    Full Text Available Central AC type water chiller is a refrigeration machine that release heat to environment. Heat energy that released to environment comes from room heat load that absorbed by machine and heat from compressor. The best form in using this loss energy is heat recovery water heater technology, where this machine will take heat from condenser by a heat exchanger to heating water. Refrigerant will flow in the heat exchanger before entering condenser, after that refrigerant flow to other components such as, expansion valve, evaporator, compressor and than return again to condenser, this process will be cycling regularly (closed cycle. Based on experimental and analysis result especially for AC with capacity 2 Pk, and tank capacity 75 liter, with water heater recovery device obtained that: (1 Compressor power consumption decrease from 1.66 kW to 1.59kW. (2 Heat rejected from condenser and used by water heater has ratio 4.683 kJ/s and 1.59 kJ/s, with water heater efficiency is 32.2%. (3 Maximum water temperature can be reached are in range 34oC – 47.5oC in 10-150 minutes and flow rate is 0.5 – 2.5 liter /min

  17. Topologically protected loop flows in high voltage AC power grids

    International Nuclear Information System (INIS)

    Coletta, T; Delabays, R; Jacquod, Ph; Adagideli, I

    2016-01-01

    Geographical features such as mountain ranges or big lakes and inland seas often result in large closed loops in high voltage AC power grids. Sizable circulating power flows have been recorded around such loops, which take up transmission line capacity and dissipate but do not deliver electric power. Power flows in high voltage AC transmission grids are dominantly governed by voltage angle differences between connected buses, much in the same way as Josephson currents depend on phase differences between tunnel-coupled superconductors. From this previously overlooked similarity we argue here that circulating power flows in AC power grids are analogous to supercurrents flowing in superconducting rings and in rings of Josephson junctions. We investigate how circulating power flows can be created and how they behave in the presence of ohmic dissipation. We show how changing operating conditions may generate them, how significantly more power is ohmically dissipated in their presence and how they are topologically protected, even in the presence of dissipation, so that they persist when operating conditions are returned to their original values. We identify three mechanisms for creating circulating power flows, (i) by loss of stability of the equilibrium state carrying no circulating loop flow, (ii) by tripping of a line traversing a large loop in the network and (iii) by reclosing a loop that tripped or was open earlier. Because voltages are uniquely defined, circulating power flows can take on only discrete values, much in the same way as circulation around vortices is quantized in superfluids. (paper)

  18. Current-voltage characteristics of a superconducting slab under a superimposed small AC magnetic field

    International Nuclear Information System (INIS)

    Matsushita, Teruo; Yamafuji, Kaoru; Sakamoto, Nobuyoshi.

    1977-01-01

    In case of applying superconductors to electric machinery or high intensity field magnets for fusion reactors, the superconductors are generally expected to be sensible to small field fluctuation besides DC magnetic field. The behavior of superconductors in DC magnetic field superimposed with small AC magnetic field has been investigated often experimentally, and the result has been obtained that the critical current at which DC flow voltage begins to appear extremely decreased or disappeared. Some theoretical investigations have been carried out on this phenomenon so far, however, their application has been limited to the region where frequency is sufficiently low or which is close to the critical magnetic field. Purpose of this report is to deal with the phenomenon in more unified way by analyzing the behavior of magnetic flux lines in a superconductor under a superimposed small AC field using the criticalstate model including viscous force. In order to solve the fundamental equation in this report, first the solution has been obtained in the quasi-static state neglecting viscous force, then about the cases that current density J is not more than Jc and J is larger than Jc, concerning the deviation from the quasi-static limit by employing successive approximation. Current-voltage characteristics have been determined by utilizing the above results. This method seems to be most promising at present except the case of extremely high frequency. (Wakatsuki, Y.)

  19. Beam tube vacuum in future superconducting proton colliders

    International Nuclear Information System (INIS)

    Turner, W.

    1994-10-01

    The beam tube vacuum requirements in future superconducting proton colliders that have been proposed or discussed in the literature -- SSC, LHC, and ELN -- are reviewed. The main beam tube vacuum problem encountered in these machines is how to deal with the magnitude of gas desorption and power deposition by synchrotron radiation while satisfying resistivity, impedance, and space constraints in the cryogenic environment of superconducting magnets. A beam tube vacuum model is developed that treats photodesorption of tightly bound H, C, and 0, photodesorption of physisorbed molecules, and the isotherm vapor pressure of H 2 . Experimental data on cold tube photodesorption experiments are reviewed and applied to model calculations of beam tube vacuum performance for simple cold beam tube and liner configurations. Particular emphasis is placed on the modeling and interpretation of beam tube photodesorpiion experiments at electron synchrotron light sources. The paper also includes discussion of the constraints imposed by beam image current heating, the growth rate of the resistive wall instability, and single-bunch instability impedance limits

  20. An innovative experiment on superconductivity, based on video analysis and non-expensive data acquisition

    International Nuclear Information System (INIS)

    Bonanno, A; Bozzo, G; Camarca, M; Sapia, P

    2015-01-01

    In this paper we present a new experiment on superconductivity, designed for university undergraduate students, based on the high-speed video analysis of a magnet falling through a ceramic superconducting cylinder (T c  = 110 K). The use of an Atwood’s machine allows us to vary the magnet’s speed and acceleration during its interaction with the superconductor. In this way, we highlight the existence of two interaction regimes: for low crossing energy, the magnet is levitated by the superconductor after a transient oscillatory damping; for higher crossing energy, the magnet passes through the superconducting cylinder. The use of a commercial-grade high speed imaging system, together with video analysis performed using the Tracker software, allows us to attain a good precision in space and time measurements. Four sensing coils, mounted inside and outside the superconducting cylinder, allow us to study the magnetic flux variations in connection with the magnet’s passage through the superconductor, permitting us to shed light on a didactically relevant topic as the behaviour of magnetic field lines in the presence of a superconductor. The critical discussion of experimental data allows undergraduate university students to grasp useful insights on the basic phenomenology of superconductivity as well as on relevant conceptual topics such as the difference between the Meissner effect and the Faraday-like ‘perfect’ induction. (paper)