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Mizuno K.,Cryogenic Systems Laboratory | Ogata M.,Cryogenic Systems Laboratory | Nagashima K.,Maglev Systems Technology Division
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2013

YBCO coated conductors attract attention because of their high critical current in high magnetic field conditions, hence calling for a suitable coil fabrication method. One of the critical problems associated with this process, however, is the negative impact on YBCO coil performance due to epoxy impregnation. Epoxy impregnation is an important technique to increase the mechanical strength and thermal conductivity of superconducting coils. However, the bonding strength of epoxy resin is stronger than the delamination strength of YBCO coated conductors in a certain direction. Therefore, thermal stress could damage epoxy impregnated YBCO coils. As a new impregnation material, we have focused on cyanoacrylate resin. Source


Mizuno K.,Cryogenic Systems Laboratory | Ogata M.,Cryogenic Systems Laboratory | Nagashima K.,Maglev Systems Technology Division
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2014

REBCO coated conductors have several characteristics which are superior to other superconductors. For example, its critical current is quite high even in the presence of high magnetic fields. Therefore, REBCO coated conductors make it possible to raise the operational temperature of superconductor applications. In turn, higher operational temperatures mean that the magnet cooling system consumes less energy. In the case of Maglev applications, it also means downsizing of the on-board power source and a reduction in the overall weight. A trial REBCO magnet that capable of generating 5 T (Tesla) was built. The magnets demonstrated that a magnetic flux density of 5 T was achievable at 45 K. Source


Nagashima K.,Maglev Systems Technology Division
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2015

RTRI is promoting the fundamental research and development concerning superconducting maglev. The topics of research are high-temperature superconducting magnet, maglev vehicles motion simulation, evaluation of the ground coil and the diagnostic technology of systems. Research on application of maglev technology to the conventional railway system is advanced in cooperation with other organizations. The main topics of this issue are a flywheel energy storage system using superconducting magnetic bearings and a magnetic refrigeration system for air-conditioners. This paper describes the existing circumstance of these researches and developments. Source


Kawada M.,Tokushima University | Suzuki M.,Yamanashi Maglev Test Center | Suzuki M.,Research and Development Promotion Division | Ikeda R.,Maglev Systems Technology Division | Ota S.,Maglev Systems Technology Division
33rd Electrical Insulation Conference, EIC 2015 | Year: 2015

Propulsion coils are used for propelling vehicles in superconducting magnetic levitation (Maglev) systems. This paper presents experimental results for finding a propulsion coil with defects by using an on-board radio interferometer system. In the experiments, the antennas of the radio interferometer system were mounted on a mock-up of the body of Maglev vehicle; considering the real operation of Maglev systems, levitation-guidance coils were arranged in front of the propulsion coils attached to the sidewall of a short-sized concrete guideway. A generalized cross correlation (GCC) was embedded in the radio interferometer system in order to estimate the time delay between signals received with the antennas with higher accuracy. The experimental results demonstrated that the propulsion coil with defects placed behind the levitation-guidance coils can be found by using the on-board radio interferometer system. © 2015 IEEE. Source


Miyazaki Y.,Cryogenic Systems Laboratory | Waki K.,Cryogenic Systems Laboratory | Arai Y.,Cryogenic Systems Laboratory | Mizuno K.,Cryogenic Systems Laboratory | And 2 more authors.
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2014

The aim of this study is to put a cooling technology using a magnetocaloric effect to practical use for air conditioners of railway vehicles in order to save energy. New magnetcaloric materials which have larger a magnetocaloric effect compared with Gd have been developed in the region of room temperature. Nevertheless, little discussion exists about how much the new materials affect the properties of a magnetocaloric cooling system. Therefore, the characteristics of the cooling system with Gd and La(Fe0.84Co 0.06Si0.10)13 have been studied experimentally and analytically. Source

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