JPS5983564A - Manufacture of insulated coil - Google Patents

Abstract

PURPOSE:To inexpensively manufacture an insulated coil which has preferably insulating characteristic with less voids by employing a ultrafine porous film as a sealing member of the coil. CONSTITUTION:A prepreg insulating tape is wound on a coil conductor 1 to form an insulating layer 2, a mold releasing tape is wound thereon to form a mold releasing layer 3. Two L-shaped side plates 4 are opposed at the periphery and contacted with each other, several positions of longitudinal direction are wound by an adhesive tape to temporarily clamp the plates 4. Then, a sealing member 5 is covered. The member 5 is an ultrafine porous Teflon film having numerous pores of the size of the degree that may pass gas, steam and solvent vapor molecules contained in the layer 3 but does not pass the heated liquid droplets such as heat-fusible asphalt compound liquid droplets.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing an insulated coil using a prepreg method.

[Technical background of the invention and its problems]

Insulated wire rings used in high-voltage, large-capacity rotating electric machines such as turbine generators are made by impregnating the tape base with thermosetting packing fat and semi-curing prepreg insulation tape, which is then wrapped around the wire conductor to form an insulating layer. There is a manufacturing method using a so-called prepreg method in which the insulating layer is formed and then heated and compressed to harden it.

The curing and molding methods of this prepreg type can be broadly classified as follows.

(a) Method of heating using steam ripening or electric heat while pressurizing with an oil press.

(b) A method in which a side plate is brought into contact with the periphery of the insulating layer, heat-shrinkable tape is wound around it, and pressure is applied using the shrinkage force of the heat-shrinkable tape when heated.

(1) A method in which the wire is placed in a vacuum Katsuji tank, and after vacuum degassing, it is cured with a heated liquid such as heated and melted asphalt compound while applying hydraulic pressure.

Although the method (a) allows manufacturing with high dimensional accuracy, it is not possible to process a large number of wires at once, and it is difficult to form curved parts. In addition, in method (b), only the shrinkage force of the heat-shrinkable tape is used to apply pressure, so the number of wraps of the heat-shrinkable tape must be increased in order to obtain sufficient pressure, making the work labor-intensive. I used to be. Furthermore, in both methods (a) and (b), if the insulating tape has many layers, it is difficult to extract the air, moisture, solvent, etc. entangled with the insulating tape to the outside. It was great to be able to obtain good insulation properties. Therefore, method (c) started to attract attention. With this method (c), a relatively large number of coils can be processed at one time, curved parts can be easily formed, and since it includes a vacuum degassing process, there are few voids in the insulating layer, and the insulation properties are also improved (b). It has the characteristic that a better product can be obtained compared to that produced by the method (b).

However, in this conventional method (c) of vacuum degassing and hydroforming, it is necessary to separate the heated liquid such as heated and melted asphalt compound from the insulating layer so that they do not fuse together. parts are required. On the other hand, this sealing member is required to have two contradictory properties: the air, moisture, solvent, etc. remaining in the insulating layer must be permeated and released to the outside as gas or vapor during the vacuum degassing process. .

Conventionally, there was no sealing material that rationally combined these two properties, and sealing materials with poor gas and vapor permeability were unavoidably used, so products with thick insulation layers had insufficient void content. There was a problem in that the insulation properties did not deteriorate and the insulation properties could not be said to be sufficiently good.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for inexpensively manufacturing an insulated coil having good insulation properties and having very few voids even when the insulating layer is thick.

[Summary of the invention]

In the present invention, a prepreg insulating tape is wound around a wire conductor to form an insulating layer, a release tape is wound around the insulating layer to form a release layer, and a release layer is formed by winding a release tape around the insulation layer. A side plate is brought into contact with the surrounding area, and the gas contained in the insulating layer is
It is covered with a sealing member made of a microporous film having numerous ventilation holes large enough to allow water vapor, solvent vapor molecules, etc. to pass through but not heated droplets, and then placed in a vacuum pressurized tank. After degassing the insulating layer, the insulating layer is pressurized and cured using heated liquid. Even though it is a hydraulic curing method, the vacuum degassing process sufficiently removes gas and water vapor in the insulating layer through the microporous film coating. , the solvent vapor molecules are extracted, and the heated liquid is prevented from adhering to the insulating layer by coating with a microporous film, making it possible to produce large quantities of insulated wire rings with few voids and good insulation properties at once. This reduces manufacturing costs.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A prepreg insulating tape is wound around the wire conductor (1) to form an insulating layer (2), and a releasable tape is wound on top of the insulating layer (2).
A ljlI type layer (3) is formed. Two L-shaped side plates (4) are placed around it, and the ridges that are in contact with each other are wrapped with adhesive tape (not shown) at several points in the longitudinal direction.
4) Temporarily fasten. Seal member (5), which will be described next.
Cover with This sealing member (5) allows gas, water vapor, solvent vapor molecules, etc. contained in the insulating layer (2) to pass through, but is large enough to not allow heated droplets such as heated molten asphalt compound droplets to pass through. A microporous Teflon film with numerous ventilation holes (not shown), such as Boretex (W, L, American product name, Core Co., Ltd.) or Microtex (Nitto Denko Co., Ltd. product name). 0
A material having 1 billion/7 or more ventilation holes of 2 to 0.6 μm is used. In this example, the above seal [(L
+J' (5) is made into a tube, a winding shaft with side plates is placed inside, and both ends of the tube are tied tightly and sealed.

At this time, wrinkles (
6) is possible. The wire ring (8) covered with this sealing member (5) is placed in the liquid tank QO) in the vacuum pressurized tank (9), and after being evacuated from the vacuum port Ql), it is placed in the liquid tank (II). Inject the heated liquid (121) of heated molten asphalt compound from the liquid injection port Oj until the wire (8) is buried.Next, close the vacuum port (11) of the vacuum pressure tank (9) and pressurize the pressure port (+41). Pressurized air is sent in from the top of the heated liquid (I'IJ) for a predetermined period of time. When the pressurization is finished, open the pressurization port 04 to release the pressurized air.
Open the liquid injection port (1 m) to remove heated liquid a, take out the wire ring (8) from the vacuum pressurized tank (9), and remove the sealing member (5), side plate (4), and mold release layer (3). is removed to obtain the desired insulated wire ring.

Next, the effect will be explained.

The wire ring (8) covered with the seal member (5) is attached to the vacuum tank (9).
), the air, moisture, and solvent contained in the insulating layer (2) turn into gas vapor, releasing the mold (
Pass through the overlapping seam of the release tape in 3), and seal member (5)
Since it is porous, it is sucked out through the ventilation holes. When the coil (8) is immersed in the heated liquid (121) and pressurized, the ventilation hole of the sealing member (5) is large enough to prevent the heated liquid droplets from passing through, so the insulation #(2) is heated. Liquid 02 does not adhere, and only heat and pressure are applied to the insulating layer (2), resulting in a high-quality insulated wire ring with few voids.Also, the microporous Teflon film has a heat resistance of 150°C or higher. Because of this, it can sufficiently withstand the temperature of heated molten asphalt compound, and there is no danger in manufacturing.This manufacturing method, similar to the conventional vacuum degassing and hydroforming methods, can process a large number of wire rings at once. The tan δ-voltage characteristics of the insulated wire produced by the conventional method and the insulated wire produced by the method of this example are shown in curves in Figure 3. Curve a is for the conventional method, and curve A is for the method of this embodiment.The tan δ-voltage characteristic is a powerful characteristic as an index for estimating the amount of voids in the insulating layer (2). However, if we compare these curves a and b, we can see that the tan δ of the insulated wire ring according to this example is much smaller than that of the conventional method even when lightning and pressure are high, and it is a good product with few voids. This indicates that it has insulating properties.

Next, another embodiment will be described with reference to FIG.

This uses a flat plate-like side plate (4) made of thin material such as fiber or a laminate, and is otherwise the same as the embodiment shown in FIG. 8141 and FIG.

In this way, the side plate (4) has a suitable degree of flexibility, so it can easily adapt to the curved part of the wire ring, making it possible to form the curved part. The same effects can be obtained.

Note that the present invention is not limited to the embodiments described above and shown in the drawings; for example, the vent holes in the microporous film used as the sealing member (5) have a diameter of 0.1 to 1.
It goes without saying that various modifications can be made without changing the gist of the invention, such as a range of 1.05 m, which is suitable for use.

〔Effect of the invention〕

As explained above, according to the present invention, in the method for manufacturing an insulated wire ring by vacuum degassing and hydroforming using a prepreg insulation method, gas, water vapor, and solvent contained in the insulating layer are used as a sealing member for the wire ring. By using a microporous film with numerous ventilation holes that are large enough to allow steam molecules to pass through but not heated droplets, we can produce insulated wire rings with good insulation properties and few voids at low cost. There is an effect that can be done.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing insulated wire manufacturing equipment in different steps in an embodiment of the insulated wire manufacturing method of the present invention, and FIG. FIG. 4 is a curve diagram showing the tan δ-voltage characteristics of the insulated wire manufactured by the method, and FIG. 4 is a cross-sectional view showing the insulated wire manufacturing apparatus in one step of another embodiment. 1... Wire conductor 2... Insulating layer 3...
Split mold layer 4... side Plate 5... sealed portion @ 8... sealed wire 9
...Vacuum pressurized tank 12...Heating liquid agent Patent attorney Inoue - Male No. 1 Fig. 3/5 (KV) No. 4 Fig. 3F

Claims (3)

[Claims] (1) Wrap prepreg insulating tape around the wire conductor to form an insulating layer, wrap a release tape around the insulating layer to form a release layer, and wrap around the release layer. It is made of a microporous film with numerous ventilation holes that are large enough to allow gas, water vapor, solvent vapor molecules, etc. contained in the insulating layer to pass through, but not heated droplets. A method for manufacturing an insulated wire ring, which comprises covering the wire with a sealing member, placing it in a vacuum heating tank, deaerating the insulating layer, and then hardening the wire with a heated liquid. (2) The diameter of the ventilation holes in the microporous film is 0.1 to 1
．． The method for manufacturing an insulated coil according to claim 1, wherein the thickness is in the range of 0 μm. (3) The microporous film is made into a tube shape, and both ☆; h
A method for manufacturing an insulated wire ring according to claim 1 or 2, characterized in that the insulated wire ring is tightly bound and sealed.