JPS59218707A - Winding method for superconductive coil - Google Patents

Abstract

PURPOSE:To contrive the prevention of a damage on an oxide film, i.e. deterioration in thermal conductivity, by a method wherein a Teflon-covered wire 2 is wound around a non-magnetic stainless steel wire between superconductive wires, thereby enabling to insulate the superconductive wires. CONSTITUTION:A Teflon-covered wire 2 having SUS 304 as a core wire is wound between superconductive wires 1 so that the superconductive wires will be electrically insulated, and an insulating film 3 is placed between layers as a spacer and to perform interlayer electric insulation. At this time, the oxide film of the superconductive wires partially comes in contact with the Teflon and the insulating film, but the heat conductivity of the oxide film is not greatly deteriorated due to the above state of contact. The stainless steel wire of non- magnetic property is to be used. When a coil is cooled, liquid Helium is infiltrated from the gap located between the superconductive wire 1 and the Teflon-covered wire 2, and the superconductive wires are cooled. When a flat type superconductive wires are used, a rectangular insulator is placed between the superconductive wires 1 and each layer as a spacer 4, thereby enabling to prevent the oxide film of the superconductive wires from heavy deterioration. As the material for said spacer Myler, FRP, Teflon and the like can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of winding a superconducting wire in which a specific surface treatment is performed, such as forming an oxide film with good thermal conductivity.

When manufacturing superconducting coils, regarding conductor insulation,
(1) Coat the conductor surface with electrically insulating enamel.

(2) Form an oxide film with good thermal conductivity, and then cover the top with an insulating coating.

The present invention relates to the above method (2).

Normally, a tape-shaped electrical insulating material is wrapped around the oxide film for electrical insulation, but since the oxide film is only a few micrometers thick and has very weak mechanical strength, this electrical insulating material may rub the surface. As a result of the oxide film being peeled off, there is a drawback that the thermal conductivity of the oxide film deteriorates.

As a result of research into ways to prevent damage to the oxide film, that is, deterioration of thermal conductivity, the present invention has developed a method of winding a non-magnetic stainless steel wire with a Teflon coating between the superconducting wires. This was achieved by discovering that the above-mentioned drawbacks could be prevented by insulating the material.

According to the present invention, as shown in the schematic cross-sectional view of a superconducting coil in FIG. 1, the superconducting wire 1 is wound with a Teflon-coated wire 2 having a core wire of 5US304 as electrical insulation between the turns. Electrical insulation film 6 as a spacer
for electrical insulation. At this time, the oxide film of the superconducting wire partially contacts the Teflon and insulating film, but this does not significantly deteriorate the thermal conductivity. Of course, the stainless steel used is non-magnetic. Liquid helium used to cool the coil enters through the gap between the superconducting wire 1 and the Teflon-coated wire 2 to cool the superconducting wire.

When the superconducting wire is rectangular, the oxide film of the superconducting wire will not be significantly degraded by inserting a strip of insulating material as a spacer 4 between each layer of the superconducting wire 1 as shown in FIG.

Mylar, FRP, Teflon, and the like are used as the spacer material.

Next, the method of the present invention will be explained using examples.

Table 1 shows the specifications of the superconducting coils and wires used in the experiments.

The Teflon-coated wire had a wire diameter of 0.75 mm (the diameter of the stainless steel wire at the core was 0.5 mm), and was wound around the superconducting wire. The thickness between the layers is 0.1 mm, and the width is 15 mm.
, an FRP board with a length of 95 mm was inserted with a gap of 15 mm (1). FIG. 6 shows the excitation/demagnetization current mode of this coil, and from the power source used for this coil, in addition to the voltage corresponding to the inductance, the noise (±150 square meters) shown in FIG. 4 was superimposed on the coil. Therefore, the peak voltage has reached 400V.

When electricity was applied in this current mode, there were no particular abnormalities (it was found that the coil characteristics were good).

Table 1 Wire and coil specifications As described above, according to the method of the present invention, there is little friction against the surface of the oxide film of the superconducting wire, so the oxide film is not damaged and the oxide film can be effectively used as a heat conductive film. can be made to work.

The turn spacing is determined by the wire diameter of the stainless-steel-filled Teflon wire, but this spacing is usually sufficient to ensure the problem withstand voltage, so sufficient electrical insulation is ensured between the turns, and in particular The present invention is extremely useful in a method of winding a superconducting magnet, such as being effective when a large withstand voltage is required.

[Brief explanation of the drawing]

3 is a cross-sectional view showing a winding method. FIG. 6 shows the excitation/demagnetization current mode of the coil of the embodiment, and FIG. 4 shows the noise waveform from the power supply. 1: Superconducting conductor wire 2 Stainless steel Teflon insulated wire Ro: Insulating film 4; Spacer Patent applicant Sumitomo Electric Industries, Ltd. Fig. 1A Fig. 4 rnS

Claims (2)

[Claims] (1) When winding a superconducting coil using a superconducting wire that has undergone a specific surface treatment, use a non-magnetic stainless steel wire coated with Teflon as electrical insulation for the superconducting wire.
A method of winding a superconducting coil characterized by winding the coil along a superconducting wire. (2) The wire winding method according to claim (1), which uses a superconducting wire in which an oxide film with good thermal conductivity is formed on the surface of the superconducting wire as a specific surface treatment.