JPS5834508A - Lead wire for cryogenic motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead wire for a cryogenic motor, and particularly to a lead wire for a cryogenic motor used when the motor is used directly in a cryogenic liquid, such as LNt (liquid nitrogen). It is related to.

In conventional high-voltage insulated lead wires used in low-temperature liquid bobbing motors, the conductor is covered with a single layer or multiple insulating layers made of synthetic rubber or the like, each layer being bonded to another. However, even materials such as synthetic rubber, which are flexible at room temperature, -1
At temperatures below 0.000 C, it does not lose its elasticity, and cracks are likely to occur when deformed. If the lead wire is deformed in such a low temperature state, the lead wire insulation will crack, resulting in dielectric breakdown.

The present invention has been made in view of the above-mentioned points, and its object is to provide leads for ultra-low-temperature motors that do not cause dielectric breakdown in the insulating layer even when the lead wires are used in ultra-low-temperature conditions. There are lines to provide.

In the present invention, the lead wire insulation has at least two or more insulating layers in which each layer is not bonded to each other, and at least one of these insulating layers is made of a material having a smaller coefficient of friction than the other insulating layers, and the lead wire insulation The intended purpose was achieved by reducing the residual strain that occurs in the lead wire insulation layer by allowing the deformation that occurs between the wires to slide through the part of the separated insulation layer that has a small friction coefficient. It is something.

The present invention will be described below based on embodiments shown in the drawings.

The figure shows an embodiment of the lead wire of the present invention. As shown in the figure, in this embodiment, the conductor 2 of the lead wire 1 is coated with an insulating layer. The inner insulating layer is made of a cross-linked polyethylene insulating layer 3 having excellent voltage resistance characteristics, and the outer two layers are made of a material having a lower coefficient of friction than the cross-linked polyethylene insulating layer 3, for example, a tube 4 made of tetrafluoroethylene. The innermost insulating layer is removed from the second insulating layer, and between the second insulating layer and the third insulating layer to remove residual strain in the insulating layer. I'm trying to keep it small.

According to this embodiment, the thickness of the lead wire can be freely selected, the insulating layer is made to slide with a layer having a low coefficient of friction, and the deformation that occurs between room temperature and low temperature is reduced by the sliding between each layer. As a result, residual strain in the lead wire can be reduced and cracking of the lead wire insulating layer can be prevented, which has the effect of preventing dielectric breakdown.

In addition, in the above-mentioned embodiment, the insulating layer is three layers, but it is possible to have two layers, four layers or more as necessary,
When insulation thickness is required, the number of insulation layers can be increased. Furthermore, the effect can be exerted even if the insulating layer with a low coefficient of friction is placed as the innermost layer. Further, in the above embodiment, tetrafluoroethylene was used as the material with a low coefficient of friction, but silicone and hexafluoroethylene also have a small Jl friction coefficient, and the same effects as in the above embodiment can be obtained.

According to the lead wire of the ultra-low-width electric motor of the present invention described above, the lead wire is drawn out from the electric motor operated in an ultra-low temperature liquid, and each layer of the insulating layer formed by covering at least two conductors is not bonded to each other. In addition, since at least one of these insulating layers is made of a material with a smaller coefficient of friction than the other insulating layers, the layer with a smaller coefficient of friction can be used to slide between the insulating layers, thereby reducing residual strain. It has the effect of preventing cracking of the lead wire insulating layer and preventing dielectric breakdown, and is very effective when used in this type of lead wire.

[Brief explanation of drawings]

The figure is a sectional view of a lead wire showing an embodiment of the present invention.

Claims (1)

[Claims] (1) In a lead wire of a cryogenic motor that is drawn out from a motor operated in a cryogenic liquid and has a conductor covered with at least two or more insulating layers, each of the insulating layers is bonded together. A lead wire for an electric motor for ultra-low temperature use, characterized in that at least one of these insulating layers is formed of a material having a smaller coefficient of friction than the other insulating layers. 2. The innermost layer of the insulating layer covering the conductor is a cross-linked polyethylene insulating layer with excellent voltage resistance characteristics, and the outermost layer is silicone and polyethylene, which has a lower coefficient of friction than the cross-linked polyethylene insulating layer. A lead wire for a cryogenic motor according to claim 1, characterized in that the lead wire is coated with an insulating layer made of any one of ethylene and hexafluoroethylene.