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process. We have been constructed and demonstrated the
levitating transporter composed of HTS bulks and
permanent magnets. The dynamic characteristics of lift
force, lateral force and magnetic stiffness are very
important for the design of the superconducting
applications such as levitation system. And the
electromagnetic phenomenon should be investigated
based on the accurate analyses on magnetic field and
shielding current distributions. In this study, we newly
developed a simulation program based on the threedimensional
hybrid finite element and boundary element
(the 3D hybrid FE-BE) method, which is combined the fast
multipole method (FMM). By using the 3D hybrid FE-BE
method, the electromagnetic phenomenon caused by
movement or displacement can be treated without
remeshing in the finite element region. This simulation
program can also consider the anisotropic and nonlinear E-
J characteristics of HTS bulks. The results of experiment
and numerical simulation were good agreement. Therefore,
we investigated the relationship between the levitation
characteristics and shielding current profiles within the HTS
bulk to find out the suitable conditions for stable levitation
using the developed computer program.
TUA12PO08
Numerical analysis of levitating force using magnetic
shielding effect of YBCO plates
T. Takao, A. Niiro, S. Suzuki, M. Hashimoto, J. Takeda,
Sophia University; H. Kamijo, Railway Technical Research
Institute.
We have studied a magnetic levitation system using a
magnetic shielding effect of high Tc superconducting
plates. In the previous work, we demonstrated the
magnetic levitation whose experimental arrangement had
three YBCO plates cooled by liquid nitrogen, and numerical
analysis data were consistent with the experimental results.
Extending the experimental arrangement, we proposed a
new system having five YBCO plates and numerically
analyzed a levitating force. According to the analytical
results, the levitating force increased approximately thirty
times as much as the force with the system of the three
plates. Those results showed a possibility of scale-up to
large-size model such as transportation systems for
railways. Furthermore, we arranged positions of a
permanent magnet and the YBCO plates, and tried to
increase the levitation force. The analytical results of the
arranged positions are also presented in the paper.
TUA12PO09
HTS Magnet for Maglev Applications: Coil
Characteristics
T. Kuriyama, K. Tasaki, T. Tosaka, S. Hanai, K. Marukawa,
T. Yamashita, Y. Yanase, M. Yamaji, H. Nakao, Toshiba
Corporation; K. Nemoto, M. Terai, M. Igarashi, S. Kusada,
S. Hirano, T. Okutomi, K. Kuwano, Central Japan Railway
Company.
An HTS magnet for Maglev applications has been
developed. The magnet consists of four persistent current
HTS coils and is operated at a rated temperature of 20 K
and a rated magnetomotive force of 750 kA for each coil.
This paper describes fabrication and test results of each
persistent current HTS coil. The HTS coil consists of 12
single-pancake coils wound with four parallel Ag-sheathed
Bi2223 wires and a persistent current switch (PCS) made
of YBCO thin films. The coil is conductively cooled by a
cryocooler to approximately 20 K. Persistent current
operating tests for four HTS coils at 750 kA were carried
out and current decay rates of 0.37-0.68 %/day were
obtained. Mechanical vibration applying tests up to ±15 G
were carried out to investigate the mechanical properties of
the HTS coils. Temperature increasing tests up to 25 K,
which is 5 K higher than the rated operating temperature
and higher magnetomotive force operating tests up to 800
kA were carried out to investigate the thermal stability of
the coils and check the mechanical strength of the coils.
TUA12PO10
HTS magnet for Maglev Applications: Magnet Structure
and Performance
M. Terai, M. Igarashi, K. Nemoto, S. Kusada, T. Okutomi,
K. Kuwano, S. Hirano, Central Japan Railway Company; T.
Yamashita, Y. Yanase, S. Hanai, K. Marukawa, T.
Kuriyama, K. Tasaki, T. Tosaka, M.Yamaji, H. Nakano,
Toshiba Corporation.
An HTS magnet for Maglev applications has been
developed. The HTS magnet is an actual device for a
Maglev vehicle and consists of four persistent current HTS
coils. The magnet is operated at a rated temperature of 20
K and a rated magnetomotive force of 750 kA for each coil.
This paper describes structure and performance test
results of the HTS magnet. These four HTS coils were
installed in a cryostat for a Maglev vehicle and conductively
cooled by two sets of two-stage GM type pulse tube
cryocoolers below 20 K. Detachable current-leads, which
consist of copper alloy leads and ultrasonic motors, are
used to reduce heat leakage to the 1st stages of the
cryocoolers. These four HTS coils were simultaneously
charged up to the rated magnetomotive force. Persistent
current operating tests were carried out and the current
decay rates were measured. To observe the mechanical
capability of the magnet, vibration tests were carried out.
The HTS magnet will be installed to the vehicle of the
Yamanashi Maglev test line.
PARALLEL SESSION 15:50 – 18:00
(Maestrale room)
MgB2
TUA1OR1
Development of MgB2conductors for AC applications
G. Grasso, A. Malagoli, INFM-LAMIA & Columbus
Superconductors srl; A. Tumino, V. Braccini, M. Tropeano,
C. Fanciulli, M. Vignolo, A. S. Siri, INFM-LAMIA; M. Bocchi,
L. Martini; CESI SPA.
In spite of its recent discovery, MgB2 conductors are
already fabricated in very long lengths for low- to medium
magnetic field generation in windings operated in DC
condition. The possibility of using MgB2 in power
applications is related to the capability of manufacturing
superconducting wires with minimized AC losses, and with
sheath materials showing mechanical, electrical, magnetic,
and thermal properties desirable for a selected device.
Considering the present behaviour of MgB2 in a magnetic
field, the first power applications that is possible to target
are Superconducting Fault Current Limiters (SFCL), and
Transformers, that involve a conductor in self-field
condition, and in a field of a few tenth of Tesla,
respectively. In order to make the use of MgB2 attractive at
low temperatures (20K-30K), it is vital to dramatically
reduce its AC losses to minimize the extra cooling costs.
The sheath material choice is much wider than for other
HTS compounds, as MgB2 shows a much broader
chemical compatibility with various elements. Nonmagnetic
and high electrical resistivity alloys can be
selected to constitute the sheath material. First results on
the optimization of the filament configuration, twisting, and
81 MT-19 2005, Genova