JPS586250B2 - Busbar mold insulation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold insulation method for bus bars used in high voltage insulated bus ducts and the like.

Conventionally, such bus bars have been manufactured by hand-wrapping insulating tape.

As a result, air bubbles remained inside, resulting in low reliability.

An object of the present invention is to provide a molding method for an insulating bus bar with very few internal air bubbles and high insulation properties.

Example In "Fig. 1", 10 is a conductor.

Strip-shaped or square, made of copper or aluminum.

20 is an insulating tape.

It is made of heat-shrinkable plastic and is wound on the conductor 10 to a thickness necessary for insulation.

Materials are cross-linked polyethylene, polyethylene, vinyl chloride,
Examples include ethylene propylene rubber.

30 is a restraining tape.

It is wrapped on an insulating tape 20.

Use plastics with high tensile strength and high heat resistance, such as tetrafluoroethylene and polyester.

It is especially convenient to use these nonwoven fabrics.

In the manner described above, a bus bar pre-molded product 50 is produced.

40 in "Fig. 2" is a holding metal fitting.

For example, one side of two flat plates 42, 44 made of steel, copper, aluminum, etc. is hinged 46, and a bolt 48 is attached to the other side.

The flat plates 42 and 44 are connected to both flat parts 52 of the pre-molded product 50.
, and press the bolt 48 appropriately.

Note that pressure contact can also be made using the force of a spring. While doing the above, place the whole thing in a heating furnace and heat it.

Alternatively, the conductor 10 and the holding fitting 40 may be heated by induction heating.

Then, the insulating tape 20 is heat molded.

At this time, since the pressure tape 20 is heat-shrinkable, when it shrinks, it expels the air bubbles inside.

The appropriate heat shrinkage of the insulating tape 20 is about 30 to 50%; if it is too large, there is a risk of tearing.

Further, between the restraining tape 30 and the restraining metal fitting 40, the restraining tape 30 works effectively particularly on the edge portion 54 of the pre-molded product 50, which is not affected by the force of the restraining metal fitting 40.

Further, the restraining metal fitting 40 does not receive much force when the restraining tape 30 alone is used.

By the cooperation of these two members, which act effectively on the flat surface 52 of the play-molded product 50, when the insulating tape 20 becomes fluid, its internal pressure is increased and air bubbles are further expelled.

In particular, when a nonwoven fabric is used for the restraining tape 30, air bubbles expelled to the outer layer of the insulating tape 20 easily escape to the outside, and air accumulation under the restraining tape 30 is eliminated.

In addition, when providing an internal semiconductive layer as in the case of a cable, as shown in "Fig. 3", the conductor 10 and the insulating tape 2
A semiconductive tape 60 is wound between the two ends.

It should be made of a material that has good adhesion to the insulating tape 20, for example, if the insulating tape 20 is made of crosslinked polyethylene, use semiconductive polyethylene, and if it is made of ethylene propylene rubber, use the same type of semiconductive rubber tape.

Other details are the same as in the above case.

Furthermore, the function of the internal semiconducting layer when it is turned into a product is the same as that of a cable.

Advantages of the Invention (1) Since heat-shrinkable plastic is used for the insulating tape 20, it acts to expel air bubbles during shrinkage as described above.

It is also effective in making the thickness of the insulating layer uniform.

(2) For example, if you try to wrap the entire molded part with a mold, such as a mold for a cable connection part, in the case of a bus bar, it will be very elongated and large.

However, in the case of the present invention, since the restraining tape 30 is used, the same purpose as using a mold can be achieved by simply pressing the flat plates 42, 44 from both sides.

That is, the edge portion 54 is held down by the pressure tape 3.
Furthermore, the flat plates 42 and 44 hold down the flat portion 52, which is difficult to apply force with the holding tape 30 alone.

In this way, the restraining metal fitting 40 and the restraining tape 30 cooperate,
To enable heating molding of busbars with a simple device.

(3) Since heat molding is performed with the necessary pressure applied as described above, an insulating bus bar with very few bubbles and good characteristics can be produced.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing an example of the present invention in the order of steps, and FIG. 3 is an explanatory diagram in the case where an internal semiconducting layer is provided. 10... Conductor, 20... Insulating tape,
30: Pressing tape, 40: Holding metal fittings, 42 and 44: Flat plate, 50: Edge portion.

Claims (1)

[Claims] 1. An insulating tape 20 made of heat-shrinkable plastic is wound on a flat conductor 10, and a restraining tape 30 is wound on top of it to make a pre-molded bus bar 50, and both flat parts thereof are wrapped. 52, the flat plates 42 and 44 of the holding fitting 40 are pressed together, and while maintaining the pressed state, the whole is heated to mold the insulating tape 20. 2. The busbar mold insulation method according to claim 1, wherein the restraining tape 30 is made of a plastic nonwoven fabric.