JPH0115122B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conductor for electric windings, which is used at high voltage and large current, such as in nuclear fusion devices, and is a hollow conductor having a solid conductor and a coolant passage through which a coolant passes. This invention relates to a conductor for electrical winding constructed by bonding.

Generally, coils used in nuclear fusion devices and the like are required to flow a large current and generate a strong magnetic field. Furthermore, due to the limit operating temperature of the coil insulator, the heat loss caused by current must be removed by direct cooling of the coil conductor. At the same time, electromagnetic force due to the coil current and high magnetic field acts on the coil conductor, generating high mechanical stress.

Generally, due to the above requirements, a large cross-section conductor is used as a coil conductor. On the other hand, it is currently extremely difficult to manufacture large cross-section long conductors with refrigerant channels.
Generally, a large cross-section solid conductor is provided with cooling grooves, and separately produced hollow conductors are bonded and integrated into the grooves of the solid conductor to form a large cross-section directly cooled coil conductor. Since the coil conductor must be able to withstand high mechanical stress, conductor materials that have been subjected to cold working to increase the proportional elastic limit are used for both the solid conductor and the hollow conductor.
Therefore, even when bonding and integrating a solid conductor and a hollow conductor, it is necessary to prevent the conductor from becoming soft due to the thermal influence during bonding and reducing the proportional elastic limit. This also applies to the conductor connections.

An example of a conventional electrical winding conductor will be explained with reference to the drawings, taking this into consideration.

FIG. 1 shows an example of a coil conductor 2 used in a large cross-section hollow conductor 1. The coil conductor 2 is directly cooled by flowing a cooling medium through a cooling medium flow path 4 provided in the conductor 3, and electrical insulation is maintained by the insulating layer 5. Second
The example shown in the figure shows a coil conductor 2 having a structure in which a solid conductor 6 and a hollow conductor 7 are made of cold-worked copper material and are integrated with a solder layer 13. In order to prevent softening due to thermal effects associated with the integration of the hollow conductors 6 and 7 (the decrease in the proportional elastic limit is simply referred to as softening hereinafter), solder with a low melting point is used, and the heating time during soldering is shortened. is also kept to the minimum necessary.

In the example shown in FIG. 3, cooling grooves 12 are provided in the solid conductors 6, and then the solid conductors 6 are connected to each other with copper welds 8, etc., and the hollow conductors 7 are soldered into the cooling grooves 12 to integrate them. The coil conductor 2 shown in FIG. The copper welded part 8 softens due to the influence of heat because it is necessary to raise the temperature of the welded part above the recrystallization temperature of the copper material. On the other hand, copper welded part 8
Since the mechanical stress σ acting on the copper weld 8 is normally a stress perpendicular to the copper weld 8, the mechanical properties of the softened portion result in determining the maximum working stress of the entire coil. For this reason, various welding methods have been developed to narrow the area affected by heat as much as possible. Normally, the electrical resistivity of the copper welded portion 8 is more than twice that of the solid conductor 6, which is the base material, due to the added impurity element.

Figure 4 shows problems in the manufacture of conductors, disassembly of coils,
Due to assembly requirements, solid conductor 6 and hollow conductor 7
The following is an example of connection when it becomes necessary to ultimately connect both at the same location. The connecting portion of the solid conductor 6 is notched, and the copper welding portion 8, which secures a working space for connecting the hollow conductor 7, is connected in the same manner as shown in FIG. The hollow conductor 7 is also integrally soldered with silver solder 10 via a conductor sleeve 9. in this case,
Similar to the base material, a large mechanical stress is generated at the connection between the hollow conductor 7 and the conductor sleeve 9, so this connection cannot be made with a low melting point, low strength material such as solder. At the same time, since the temperature during brazing is higher than the recrystallization temperature of the copper material and softening occurs, a hollow conductor 7 is connected to the solid conductor 6 so that the solid conductor 6 and the copper welded part 8 do not soften during brazing. It is necessary to provide a notch 11 to ensure sufficient space for heating. in this way,
In the conventional coil conductor connection structure, the specific resistance of the copper welded part 8 increases, and at the same time, this part is cut out to connect the hollow conductor 7, increasing the current density and making direct cooling impossible. The disadvantage was that the temperature of the parts became high, which caused thermal deterioration of the insulators.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to prevent the temperature of the connected portion from increasing when electricity is applied even when a solid conductor and a hollow conductor are connected at the same place. Another object of the present invention is to provide a conductor for electrical windings whose insulators are not thermally degraded.

The present invention provides a solid conductor formed by metallurgically connecting a plurality of conductors;
At least the connecting portion of the hollow conductor is connected via the conductor sleeve at a position an appropriate distance from the connecting portion and has a refrigerant flow path approximately in the center, and a heat conductive segment disposed between the two is connected to the connecting portion via the conductive sleeve. The intended purpose is achieved by connecting with a low melting point alloy.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings. Incidentally, the same reference numerals are used for the same parts as in the past.

FIG. 5 shows an embodiment of the electrical winding conductor of the present invention. In this embodiment as well, the solid conductor 6 is provided with a notch 11 for connecting the hollow conductor 7, and the solid conductors 6 are connected to each other by a copper weld 8. The hollow conductor 7 is fixedly bonded to the cooling groove 12 of the solid conductor 6 with a solder layer 13 by soldering, and after the solid conductors 6 are fixed by connection, the hollow conductor 7 is soldered with silver solder via the conductor sleeve 9. Attach. In this embodiment, a heat conductive segment 14 made of copper is arranged between the conductor sleeve 9 and the solid conductor 6, and heat conduction is conducted through the conductor sleeve 9 and an alloy having a lower melting point than the solid conductor 6, such as a solder layer 13. The segment 14 is fixedly bonded near the connection between the conductor sleeve 9 and the solid conductor 6.

By having the configuration of this embodiment as described above,
An increase in the temperature in the copper weld 8 due to an increase in the specific resistance of the copper weld 8, an increase in current density due to the provision of the notch 11, and an increase in the length of the part that cannot be directly cooled occurs in the copper weld 8. The heat is transferred to the heat conduction segment 14 by thermal conduction, and further to the conductor sleeve 9.
Since the heat is transferred to the cooling medium through the heat exchanger and removed, the temperature is kept to a considerably low level, and the temperature of the connecting portion does not rise when electricity is applied, and the insulator does not deteriorate over time.

FIG. 6 shows another embodiment of the invention. The embodiment shown in the figure also has a heat conduction segment 14 disposed between the solid conductor 6 and the conductor sleeve 9, and the heat conduction segment 14 is placed near the connection between the conductor sleeve 9 and the solid conductor 6 through the solder layer 13. However, in this embodiment, there is no cutout near the connection part of the solid conductor 6, and the connection part of the hollow conductor 7 is formed in a substantially U-shape. is placed at an appropriate distance from the solid conductor 6. With this configuration, a space for connecting the hollow conductor 7 is secured, and the effect is exactly the same as that of the embodiment described above.

Note that if it is necessary to simply connect only the hollow conductor 7, it will be necessary to separate the hollow conductor 7 from the solid conductor 6 in order to secure the connection space, and it will not be possible to directly cool a part of the hollow conductor 6. Although some parts occur,
If the hollow conductor 7 and the solid conductor 6 are fixed and integrated via the heat conductive segment 14 as in this embodiment, direct cooling becomes possible, which is also advantageous in this case.

According to the electrical winding conductor of the present invention described above, the solid conductor formed by metallurgically connecting a plurality of conductors is located at approximately the same position as the connection part of the solid conductor, and at a position more suitable than the connection part. At least the connection portion of a hollow conductor that is connected via a conductor sleeve at a distance and has a refrigerant flow path approximately in the center is made of a low melting point alloy through a heat conductive segment disposed between the two. Since the heat generated at the metallurgical connection of the solid conductor is conducted directly to the cooled hollow conductor through the heat-conducting segment, the temperature rise in this part is suppressed. This has the effect of preventing thermal deterioration of the insulator.

[Brief explanation of drawings]

1, 2, and 3 show general electrical winding conductors, and FIG. 1 is a partially sectional perspective view;
FIG. 2 is a sectional view, FIG. 3 is a perspective view, FIG. 4 is a partially sectional perspective view of a conventional electric winding conductor, and FIG. 5 is an embodiment of the electric winding conductor of the present invention. FIG. 6 is a perspective view showing another embodiment of the present invention. 1...Large cross-section hollow conductor, 2...Coil conductor, 3
...Conductor, 4...Refrigerant channel, 5...Insulating layer, 6...
...Solid conductor, 7...Hollow conductor, 8...Copper welded part,
9... Conductor sleeve, 10... Silver solder part, 11...
...Notch, 12...Groove, 13...Solder layer, 14...
...Thermal conduction segment.

Claims (1)

[Scope of Claims] 1. A solid conductor formed by metallurgically connecting a plurality of conductors, and a conductor sleeve located at approximately the same position as the connection part of the solid conductor and at an appropriate distance from the connection part. The solid conductor and the hollow conductor are connected to each other through a hollow conductor having a coolant flow path through which a coolant passes approximately in the center, and the solid conductor and the hollow conductor are integrated at least in a portion other than the connecting portion. 1. A conductor for electric winding, characterized in that at least a connecting portion of the solid conductor and the hollow conductor is connected by a low melting point alloy via a heat conductive segment disposed between the solid conductor and the hollow conductor. 2. The electrical winding conductor according to claim 1, wherein the thermally conductive segment has the conductor sleeve and the solid conductor connecting portion fixedly integrated with each other by a solder layer made of a low melting point alloy. .