JPS60130179A - Superconductive switch - Google Patents

Abstract

PURPOSE:To enable use at a high load factor by a method wherein a switch is impregnated with an alkali halide or the mixed crystal of two kinds or more of alkali halides. CONSTITUTION:A superconductive conductor 2 of cupro Ni matrix is wrapped with a glass series 3. The switch is wound up by non-inductive winding with this conductor. The switch is wound in two layers at a time because of non-inductive winding. Heaters 4 to be used for the on-off operation of the switch are wound in at every two layers. The coil of the superconductive switch thus wound up is impregnated with alkali halide sufficiently, which element is then solidified. Such a manner forms an electric insulation layer of good thermal conductivity on the surface of the superconductor; therefore, even when heat generates in the switch, the most part of this heat diffuses through the alkali halide layer, and only a part of the amount of heat reaches the superconductor, not leading to quench due to heat generation.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field to Which the Invention Pertains The present invention relates to a superconducting switch used in a magnetically levitated train or the like, and particularly relates to an insulating material for a superconducting switch.

Prior Art and its Problems] A superconducting switch is a device required when a superconducting coil is used in persistent current mode. This switch connects two coils in parallel, and when the switch is turned on, it becomes superconducting, and when it is turned off, it becomes normal conduction. Turn off the switch to excite the coil, and after excitation, turn on the switch to create a closed loop (persistent current loop) consisting of the coil and switch.

In order to minimize the current flowing through the switch during coil excitation, it is necessary to make the electrical resistance sufficiently large when the switch is turned on. For this reason, superconducting conductors do not use so-called stabilizing materials such as copper or aluminum, but instead use conductors with a matrix of high-resistance metals such as cupronickel. In a conductor with a matrix stabilizing material, most of the weak heat generated by movement of the conductor due to electromagnetic force is due to the low thermal conductivity of cupronickel in a conductor that uses a stabilizing material with good thermal conductivity. The above heat generation is trapped in a part of the conductor, and the temperature of the conductor increases, which tends to lead to quenching.

For this reason, superconducting switches are quenched by slight heat generation within the switch, resulting in poor stability and, as a result, they can only be used at current values that are much lower than expected from the characteristics of the superconducting conductor used. The disadvantage was that the load factor was low.

OBJECTS OF THE INVENTION The object of the present invention is to provide a method for improving the above-mentioned drawbacks so that a superconducting switch can be used at a higher load factor than before.

[Summary of the invention]

In the present invention, a switch is impregnated with an alkali halide or a mixed crystal of two or more types of alkali halides after winding using a superconducting conductor wound with glass thread. The purpose is to manufacture a superconducting switch by winding a conductor.

[Effects of the Invention] According to the present invention, an electrically insulating layer with good thermal conductivity (i.e., an alkali halide layer) is formed on the surface of a superconducting conductor, so that cracks in the impregnated material and damage to the conductor due to electromagnetic force inside the switch are prevented. Even if movement occurs and heat is generated, most of this heat will be thermally diffused through the alkali halide layer,
Since only a small portion of the heat reaches the superconducting conductor,
A stable superconducting switch that is unlikely to be quenched due to such heat generation can be manufactured.

[Embodiments of the invention]

FIG. 1 and FIG. 2 show the configuration of a superconducting switch. (1
) is the winding frame, and (2) is a cupronickel matrix superconducting conductor. This conductor is wrapped with glass (3). This conductor is used to wind the switch using non-inductive winding. Since the switch is non-inductively wound, two layers are wound at once. A heater (4) for turning the switch on and off is wound into each of these two layers. The superconducting switch wound up in this manner is placed in a heated alkali halide bath to allow the alkali halide to sufficiently soak into the coil, and then cooled to room temperature to solidify.

When the superconducting switch manufactured as described above was operated in a magnetic field created by another superconducting magnet in a cryostat containing a liquid helium, almost no quenching occurred.

The same effect can be expected not only in this embodiment but also in the case where a switch is manufactured using a superconducting conductor sheathed with the above-mentioned alkali halide or its mixed crystal and having a cross section as shown in FIG. 13. Here, (5) in the figure is NbTi core wire, (6)
The cupronickel matrix (7) is an alkali halide sheath.

[Brief explanation of the drawing]

1 and 2 are configuration diagrams showing an embodiment of a superconducting switch according to the present invention, in which FIG. 1 is a perspective view, FIG. 2 is a sectional view taken along line A-A' in FIG. 1, and FIG. This is a garden showing a cross section of a conductor. (1)... Winding frame (2)... Superconducting conductor (3)...
・Glass thread wrap (4)...Heater (5)...N
bTi core wire (6)...Cupronickel matrix (7)...
Alkali halide sheath Figure 1 Figure 3

Claims (2)

[Claims] (1) In a superconducting switch using a superconducting conductor that does not contain copper, aluminum, etc. for stabilization,
The switch should be made of alkali halide or 2, which has good thermal conductivity.
A superconducting switch characterized by being impregnated with a mixed crystal of alkali halide or more. (2) A superconducting switch characterized in that a superconducting conductor is sheathed with an alkali halide or its mixed crystal and then wound with the sheath.