JPS59218783A - Thermal superconductive switch - Google Patents

Abstract

PURPOSE:To obtain a thermal superconductive switch which has working steps entirely different from a thermal superconductive switch by forming an electrically insulating layer Nb3Sn layer on a substrate used also as a heater, winding it in a pancake shape and molding it with epoxy. CONSTITUTION:In a thermal superconductive switch necessary to perform a superconductive permanent current mode used for a magnetically levitating train or the like, a substrate 1 is formed of stainless steel and used also as a superconductive switch OFF heater. Accordingly, it has low electric conductivity and is selected to have durability against heat such as metallizing or heat treatment of Nb3Sn. An electric insulator 2 such as ceramics is coated on the substrate 1. The Nb3Sn layer 3 is metallized thereon. This tape is the heat treated in a heating furnace to form the layer 3 tape having high critical current and high critical temperature. This tapelike superconductive conductor is wound in a pancake shape through an electrically insulating tape 4, covered with resin such as epoxy as a thermally insulating layer 5. Or, the electrically insulating tape is omitted, and an electric insulator to be coated on the substrate 1 instead may be coated on both sides of the tape. In this manner, the manufacturing workability can be remarkably improved, and arbitrary normal conductive resistance value and thermal capacity thermal superconductive switch can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a thermal superconducting switch used in magnetic levitation trains and the like, which is necessary to achieve a superconducting persistent current mode.

[Prior art and its problems] Conventionally, superconducting switches have used Nb'I"i superconducting wires or NbTi superconducting wires with a CuNi base material.NbT
A more stable superconducting switch can be realized by using Nb5sn, which has a high superconducting transition temperature, and such a proposal has also been made.

However, all of these methods have problems with workability due to the structure in which the superconducting wire and heater f are wound around a four-winding frame, and the inconvenience that the normal conductive resistance and heat capacity of the superconducting switch cannot be arbitrarily selected due to constraints in the manufacturing of the superconducting wire. [Objective of the Invention] It is an object of the present invention to solve the above-mentioned inconveniences and to provide a superconducting switch that has a completely different working process from conventional superconducting switches.

[Outline of the invention] This invention provides an electrically insulating layer NbaS on a substrate that also serves as a heater.
An n-layer is formed, wound into a pancake shape, and molded with epoxy or the like.

[Effects of the Invention] By carrying out the present invention, manufacturing workability is significantly improved, and a superconducting switch having any normal conductive resistance value or heat capacity value can be obtained. Thermal contact with the heater is also improved compared to the conventional method.

[Embodiments of the invention] Specific embodiments of the present invention will be shown below based on the drawings.

FIG. 1 is a sectional view of a tape-shaped superconducting wire, and FIG. 2 is a perspective view of a superconducting switch. FIG. 3 is a cross-sectional view of plane A in FIG. 2. l is a substrate made of stainless steel or the like. Since it also serves as a heater for turning off the superconducting switch, any material may be used as long as it has low electrical conductivity and can withstand heat such as thermal spraying and heat treatment of Nb3Sn.

An electrical insulator 2 such as ceramic is coated thereon. A NbaSn layer 3 is thermally sprayed onto this. This tape was heat-treated in a heating furnace to produce Nb3S with a high critical current and critical temperature.
It is an n-layer tape.

This tape-shaped superconducting wire is wound into a pancake shape with an electrically insulating tape 4 interposed therebetween and covered with a resin such as epoxy to form a thermally insulating layer 5. The electrically insulating tape may be omitted and instead the electrically insulating material coated on the substrate 1 may be applied on both sides of the tape.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the tape-shaped superconducting wire used in the present invention, Figure 2 is a cross-sectional view of the tape-shaped superconducting wire used in the present invention,
The figure is a perspective view of the thermal superconducting switch of the present invention, and FIG. 3 is a cross-sectional view of A in FIG. 2. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Electrical insulating layer, 3... Nb3S
n layer, 4... electrical insulation tape, 5... thermal insulation layer. Figure 1 Figure 3

Claims (1)

[Claims] A tape-shaped superconducting wire made by thermally spraying a superconducting Nb3Sn layer on an electrical insulating layer coated on a tape-shaped substrate with high heat resistance and low electrical conductivity is wrapped in a pancake shape through an electrical insulating tape and molded with resin. Features of thermal superconducting switch.