Cryogenic Systems Laboratory

Laboratory, Japan

Cryogenic Systems Laboratory

Laboratory, Japan

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Kato Y.,Electromagnetic Systems Laboratory | Hasegawa H.,Cryogenic Systems Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2015

In Japan, regulations on low-frequency magnetic fields came into force. Initial regulations in 2011 applied to power equipment in general, but the scope of regulatory control was expanded in 2012 to cover track-side railway power equipment. Although railway vehicles are not included in the scope of the regulation at the moment, it thought that it is necessary to assess magnetic fields in railway vehicles. As such a series of studies have been launched to develop a method to measure and predict low-frequency magnetic fields in railway vehicles.


Mizuno K.,Cryogenic Systems Laboratory | Sugino M.,Cryogenic Systems Laboratory | Ogata M.,Cryogenic Systems Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2016

Work has been conducted to develop REBCO (Rare-Earth Barium Copper Oxide) magnets for Maglev. REBCO is one of several high temperature superconducting materials and has a high current density at high temperatures and in high magnetic field environments. The REBCO coated conductor will make it possible to raise the operating temperature of on-board magnets without increasing the coil weight. Since liquid helium is unnecessary for cooling REBCO coils, magnet operation is easier than that with low temperature superconducting magnets. The aim of this research is the development of a real-size REBCO coil and demonstration of its actual magnetomotive force on Maglev. This paper describes the conceptual design of the on-board REBCO magnet and the experimental production of racetrack pancake coils which constitute the real-size REBCO coil.


Hasegawa H.,Hydrogen and Sustainable Energy Laboratory | Matsue H.,Cryogenic Systems Laboratory | Nagashima K.,Maglev Systems Technology Division | Yamashita T.,Maglev Systems Technology Division
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2016

Financially supported by the New Energy and Industrial Technology Development Organization in Japan, the Railway Technical Research Institute has co-developed a flywheel energy storage system in association with KUBOTEK, FURUKAWA ELECTRIC, MIRAPRO and YAMANASHI prefecture. The flywheel system was chosen as an energy storage medium because in terms of life span, cost, capacity and output power, flywheel energy storage systems offer more advantages than other energy storage systems. It stores energy in the form of kinetic energy. Therefore, there is no electrochemical damage. This paper first describes the effect of the flywheel energy storage system, and then presents details of the equipment used in a demonstration test.


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.


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.


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.


Miyazaki Y.,Cryogenic Systems Laboratory | Waki K.,Cryogenic Systems Laboratory | Mizuno K.,Cryogenic Systems Laboratory | Ikeda K.,Cryogenic Systems Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2015

Present air conditioner systems are based on traditional vapor compression technology with usage of HCFC (Hydro Chloro Fluoro Carbon). The Kyoto Protocol has designated HCFC as one of the gases whose emissions are to be reduced. This requires the development of HCFC free systems or the usage of substances which have little greenhouse effect. Under these conditions, magnetic refrigeration technology, which has the potential for high efficiency without Freon gases, has become a focus of attention. The aim of this study is to develop a large-scale magnetic refrigerator which has a maximum kilowatt-class cooling power for airconditioners mountable on railway vehicles to enable them to be free from Freon gases.


Sugino M.,Cryogenic Systems Laboratory | Ogata M.,Cryogenic Systems Laboratory | Mizuno K.,Cryogenic Systems Laboratory | Hasegawa H.,Cryogenic Systems Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2015

Monitoring the temperature inside superconducting magnets is an effective way to detect failures and prevent damage to the magnet. It is possible to measure the multipoint temperatures with one optical fiber sensor thread. The sensor is suitable for measuring the temperature inside cryogenic equipment because of its low heat invasion and high voltage insulation in comparison with the resistance temperature sensors such as CERNOX, thermocouples, etc. However, there have been almost no cases where the optical fiber sensors have actually been used at cryogenic temperature. Investigations where therefore carried out into optical fiber temperature sensors that can be used at cryogenic temperature, to monitor the temperature inside superconducting magnets.

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