1. Development of Current Lead-eliminating Gas Cooling for Superconducting Magnet

  • Development of current lead-eliminating gas cooling for superconducting magnet.
  • Cutting of thermal loads by about 60% from those of the full time current transport lead

The current lead used for superconducting magnets (SCMs) in MAGLEV systems electrically connects the power source located in the external space at normal temperature and the inside of SCMs, which constitutes a current passing route when the SCMs are magnetized or demagnetized. Copper has conventionally been used as the material for this current lead conductor. However, to combat the joule heat generated by the large current flowing in the conductor and the heat conducting into SCMs through the conductor, the current lead is fitted with a gas cooling mechanism using helium gas evaporated inside the SCMs (Fig. 1 (a)).

The RTRI developed a new current lead combining a high-temperature superconducting (HTS) lead (featuring the characteristics of low-rate heat conduction and a low degree of joule heat generation) with a low-duty type of copper lead having a short-time rated capacity for thermal loads that is about 60% lower than that of the full time current transport lead (Fig. 1 (b)). An SCM incorporating the new current lead that does not require a gas-cooling mechanism (Fig. 2) has also been developed. As a result, work related to the cooling gas (which was previously essential in magnetizing and demagnetizing SCMs) has been completely eliminated. In addition, the elimination of the gas cooling mechanism has enabled the simplification of SCMs with respect to software and hardware. The RTRI plans to study its vibration-withstanding characteristics and operational features to further raise the reliability of SCMs.

This study was executed with a subsidy from the Ministry of Land, Infrastructure and Transport.

Fig. 1 Structure of current lead system Fig. 2 Appearance of a superconducting magnet

R&D > Major Results of Research and Development in Fiscal 2006 > V Maglev System


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