Entity

Time filter

Source Type


Deng Z.,Tokyo University of Marine Science and Technology | Deng Z.,Southwest Jiaotong University | Izumi M.,Tokyo University of Marine Science and Technology | Miki M.,Tokyo University of Marine Science and Technology | And 6 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2012

The strongly connected or coupled grain boundaries (GBs) between adjacent grains and their macroembodiment as flowing intergrain supercurrents crossing the GBs inside multiseeded bulk high-temperature superconductors were elucidated by trapped-flux evaluation. Trapped-field measurements, after cutting and polishing two multiseeded YBCO bulk samples, were conducted to present the existence of coupled GBs and their distribution along the c-axis growth. The intensive trapped-flux density observed near the GB areas inside the whole sample is direct evidence of a strongly connected or coupled GB. The relatively strong trapped flux near the GB areas and the significant improvement of the total trapped flux compared with the isolated single-grain bulks were ascribed to the intergrain supercurrent flowing across the GBs in large macroscopic loops with coordination of the intragrain supercurrent circulating in each grain of the multiseeded bulk. Based on the experimental results, a simplified simulation model that incorporates two forms of the intra- and intersupercurrents flowing inside the multiseeded bulk is introduced to reproduce the trapped-flux density features, and qualitative agreement is obtained by comparison with the experimental ones. © 2011 IEEE. Source


Werfel F.N.,Adelwitz Technologiezentrum GmbH ATZ | Floegel-Delor U.,Adelwitz Technologiezentrum GmbH ATZ | Riedel T.,Adelwitz Technologiezentrum GmbH ATZ | Rothfeld R.,Adelwitz Technologiezentrum GmbH ATZ | And 4 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2010

Adelwitz Technologiezentrum (ATZ) and L-3 Communications Magnet Motor (L-3 MM) are currently mounting a compact-designed flywheel energy storage system (FESS) with total magnetic bearing support. Final assembly and test operation were performed during 2008-2009. After calculations and experiments, we decided to improve rotor stabilization by stiffer geometry. In addition, two dynamical emergency bearings contribute to robust and safe flywheel operation in critical revolution-per-minute situations. A planned energy capacity of 5 kWh is now obtained at about 8000 r/min, whereas an increased capacity of 10 kWh will be stored at a speed of 10000 r/min. The total weight of the flywheel unit is about 1200 kg plus power electronics and cooling system. The heavier 600-kg rotor causes new design and construction work in mechanical elements, magnetic support bearings, cooling, and power electronics. Due to the here reported construction changes and increased rotor speed, scaling to even larger energy storage performance of 1520 kWh seems achievable. ATZ and L-3 MM obtained a corresponding order to develop and deliver a 15-kWh/400-kW high-temperature- superconducting FESS for a Korean local grid UPS application. © 2006 IEEE. Source


Floegel-Delor U.,Adelwitz Technologiezentrum GmbH ATZ | Riedel T.,Adelwitz Technologiezentrum GmbH ATZ | Wippich D.,Adelwitz Technologiezentrum GmbH ATZ | Goebel B.,Adelwitz Technologiezentrum GmbH ATZ | And 5 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2011

By applying high-rate copper electroplating technique the reliable fabrication of a copper stabilizer on coated conductor with an 1 μm Ag cap is investigated. The obtained mechanical, electrical and encapsulation properties due to a 20 μm thick Cu stabilizer on the surface improve the practical and technical performance. A copper sulphate CuSO4 based pulse plating technique is capable to deposit a 20 micrometer thick copper layer in a fast and continuous non-vacuum process. A surround Cu layer protects the HTS conductor surface against salt aqueous solutions, humidity, and against cryogenic liquids LN2 and liquid helium. With the copper stabilizer conductor solder joining with a contact resistance of 200 nΩcm2 becomes possible. Further effort is being made to develop and construct a high-rate and high throughput continuous reel-to-reel modular plating unit for deposition of long length (>400 m). The paper describes the practical achievements within the conductor fabrication. © 2010 IEEE. Source


Floegel-Delor U.,Adelwitz Technologiezentrum GmbH ATZ | Riedel T.,Adelwitz Technologiezentrum GmbH ATZ | Wippich D.,Adelwitz Technologiezentrum GmbH ATZ | Rothfeld R.,Adelwitz Technologiezentrum GmbH ATZ | And 5 more authors.
Journal of Physics: Conference Series | Year: 2014

Bruker HTS manufactures YBCO based superconducting wires of the second generation on low- cost Stainless Steel substrate (100 μm thick). With 250-500 A/cm@77 K, SF, 650 MPa tensile strength and 6 mm bending radius excellent electrical and mechanical properties are achieved. As complementation of the 2G fabrication technology an automated 2 km copper pulse plating facility has been installed in 2012. We report here the operation requirements and the experiences of the copper plating technique. Source


Werfel F.N.,Adelwitz Technologiezentrum GmbH ATZ | Floegel- Delor U.,Adelwitz Technologiezentrum GmbH ATZ | Riedel T.,Adelwitz Technologiezentrum GmbH ATZ | Wippich D.,Adelwitz Technologiezentrum GmbH ATZ | And 2 more authors.
Journal of Physics: Conference Series | Year: 2010

A 5 kWh / 250 kW engineering prototype Flywheel Energy Storage System (FESS) was designed and assembled in a joint project ATZ with L-3 Magnet- Motor Corp. The 0.6 t rotor is magnetically stabilized between a 1 ton magnetic HTS bearing on top and a new PM bearing. Based on the measured bearing load (max. 10000 N), Stiffness (3-4 kN/mm axial, 1.8 kN/mm radial) and rotor eigenfrequency (∼ 6.5 Hz) optimum operating conditions are obtained. For industrial use the flywheel periphery is described and evaluated. A comparison and evaluation showed, both the composite rotor as well the HTS magnetic bearing are utilized more efficient in systems with larger energy storage capacity. This can provide UPS function as well as power quality (load levelling) economically and correspond to industrial requirements and demands. In a third phase starting in 2009 the parameters for larger energy storage capacity 25 - 50 kWh are calculated, investigated and the basic elements studied. © 2010 IOP Publishing Ltd. Source

Discover hidden collaborations