JPS62196052A - Manufacture of electrical insulated coil - Google Patents

Abstract

PURPOSE:To improve dielectric strength by forming an insulating layer on a winding conductor surface and overlapping winding a heat-shrinkable tape on said surface so as to form a resin leak preventive layer. CONSTITUTION:A dry mica tape containing a small quantity of adhesives is wound around a winding conductor 1 wound like a coil to form an insulating layer 1. Also, a heat-shrinkable polyimide film tape is wound on the surface of the insulating layer 2 to form a resin leak preventive layer 3. A plurality of these coils are housed in an iron core and a connection is prepared in a prescribed manner. In said connection also, an insulating layer 2 and a resin leak preventive layer 3 similar to those as mentioned above are provided to form an electrical winding. Then, this winding together with the iron core is impregnated with thermosetting resin which is made to harden by heating. In this way, the insulating layer 2 can be closely pressure-formed while a heat- shrinkable film tape itself can also be adhered closely in a heating process for hardening the impregnated resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing an electrically insulating coil that has excellent resin retention properties and can be used as seed insulation.

[Conventional technology]

There are two methods for manufacturing insulated wire rings for high-voltage rotating electric machines: a vacuum pressure impregnation method and a resin-rich method. In the full impregnation method, in which a wire ring is attached to an iron core and is impregnated with resin, there is a risk that the impregnated resin may flow out during the heat curing process after impregnation. When the resin in the amorphous layer flows out, harmful voids are formed in the high voltage insulation coil. Therefore, it is essential to prevent the formation of voids in high voltage insulated coils. Various methods have been considered to prevent resin leakage, but
There are the following drawbacks, especially for H class insulation:
Due to its high application temperature, there has been no satisfactory prevention method.

[Problem that the invention seeks to solve]

One method for preventing resin leakage is to wrap a heat-shrinkable polyethylene terephthalate film around the surface of the insulating layer and mold it using the shrinkage force during heat curing. However, this film has a heat resistance of at most 150°C or less and cannot be applied to H type insulation up to 180°C. Furthermore, although heat-shrinkable aramid paper tapes are wound, they are heat resistant, but have the disadvantage that the tape itself allows low-viscosity liquid resin to pass through, so its leakage prevention effect is somewhat weakened. Furthermore, because heat-shrinkable aramid paper tape is made from fibrids (pulp-like particles) rather than aramid fibers, its tensile strength is low, and it is easy to break at wire loops, etc., which require large winding tension, resulting in poor winding workability. .

Another method is to wrap the insulating layer with a material with high resin retention properties such as felt or non-woven fabric, but since the surface of these materials has fuzz, if the insulating wire is heated after being impregnated, resin will adhere to the fuzz. The wire hardens while remaining in place, the apparent size of the wire becomes larger, and there is no gap between adjacent wires. Therefore, the cooling air for the equipment cannot pass through the gap, causing an abnormal temperature rise in the electrical machine, which may lead to a serious accident.

Furthermore, in the resin-rich insulation method, there is an extremely economical manufacturing method in which a wire ring with a heat-shrinkable material wrapped around the insulation surface is assembled into an iron core and then heated and hardened.

However, it has not been put into practical use as heat-resistant insulation because there is no suitable heat-shrinkable material with heat-resistant class H heat.

It is an object of the present invention to provide a method for manufacturing an electrical insulating wire ring, which can be applied not only to insulation with low heat resistance properties but also to heat-resistant class H insulation, and which allows air gaps to be easily formed due to resin flow out of the insulating layer.

[Means for solving problems]

In order to achieve the above object, in the present invention, in a method for manufacturing an electrically insulating wire ring using a vacuum pressure impregnation method or a resin rich method, an uncured thermosetting resin is added afterwards or pre-impregnated. A resin leak prevention layer is formed by winding a heat-shrinkable polyimide film tape or sheet around the ticket on the outside of the insulation layer formed by winding the insulation tape, and is heated to shrink the resin leak prevention layer and remove the insulation layer. Harden the resin inside.

[For production]

In the present invention, a heat-shrinkable polyimide film tape or sheet having class II heat resistance is wound around the ticket on the surface of the insulating layer, so heat is applied to harden the thermosetting resin contained in the insulating layer. Then, the tape or sheet shrinks to prevent the resin from flowing out, form an insulating layer without voids, and manufacture an H-class insulated wire.

〔Example〕

The present invention will be explained in detail below based on Examples 1 and 2.

First, various properties of the heat-shrinkable polyimide film tape used in the present invention will be described. An unstretched Upilex film (product name of polyimide film manufactured by Ube Industries, Ltd.) catalog number 20R was stretched under a tension of 2 g/10 mm width to form a heat-shrinkable polyimide film (thickness 0.5 mm).
02++uw) was obtained. Since the material of this film is polyimide resin, it is physically, mechanically, and
The electrical and chemical properties are significantly superior to conventional polyethylene terephthalate film as well as aramid paper tape. For example, after heating for 20,000 hours, the temperature at which the tensile strength is halved is 270°C, which shows that it has excellent long-term heat resistance. This heat-shrinkable polyimide film was cut into a tape shape with a width of 19 mm, and the heat shrinkage rate at each temperature was measured. How to measure?

Gauge points were drawn at 200 mm intervals on the film surface, and the change in the distance between the gauges after heating at each temperature for 40 minutes was determined to be the heat shrinkage rate. The results are shown in Table 1 in comparison with a conventional heat-shrinkable aramid paper tape (A Tissue ATU50, manufactured by Nippon Aroma Co., Ltd.).

The heat-shrinkable polyimide film used in the present invention begins to shrink at a relatively low temperature of about 100° C., and the heat shrinkage rate increases as the temperature increases. In contrast, conventional heat-shrinkable aramid paper begins to shrink at a high temperature of about 150° C., but its heat shrinkage rate is as low as about 172 or lower than that of the present invention. In addition, the tensile strength is much higher at about 20 kg/+nn+'' compared to about 3 kg/mi'' for conventional heat-shrinkable aramid paper. The dielectric breakdown voltage is also large, about 270 kV/mm, compared to 30 kV/mm for heat-shrinkable aramid paper. Conventional heat-shrinkable aramid paper has a density of 0.51g/a due to its so-called paper quality.
I? Although the heat-shrinkable polyimide film of the present invention is a film, it does not pass through it at all.

Example 1 As shown in Fig. 1, a so-called dry mica tape with a small amount of adhesive and a thickness of 0.1 was applied to a wire-wound conductor (1) wound into a ring shape.
An insulating layer (2) is formed by winding a 6 mm film 5 times with 172 turns. Heat 2 to a thickness of 0.02 mm on the surface of the insulating layer (2).
A resin leakage prevention layer (3) is formed by wrapping a shrinkable polyimide film tape once in a 1/2 fold. A plurality of these wire rings are housed in an iron core, and predetermined connections are made, and the same insulating layer (2) and resin leakage prevention layer (3) as described above are also provided at the connection part,
Form electrical windings. This winding wire was placed together with the iron core in a vacuum tank, and 47 parts by weight of Epicoat 807 (trade name of Shell Chemical Co., Ltd.), 8 parts by weight of butyl glycidyl ether, IN22
00 (trade name, Hitachi Chemical Co., Ltd.) 45 parts by weight of a thermosetting resin was impregnated under vacuum pressure. Thereafter, it is heated and cured at 150° C. for 15 hours to obtain a desired electrically insulating winding.

Next, the effect will be explained. The heat-shrinkable polyimide film tape forming the resin leakage prevention layer (3) has a thickness of 0.
Although it is extremely thin at 0.02 mm, its tensile strength is approximately 8 kg/19
+*m and has an elongation of 100% or more, so it can be wrapped with a large tension and has the advantage of adhering well to the insulating layer (2). In addition, as mentioned above, the heat shrinkability is extremely high, so the insulating layer (
At the same time as 2) is densely pressure-molded, the heat-shrinkable film tape also adheres closely to itself, and since it is film-like, the impregnated resin does not pass through, which prevents the resin from flowing out and creating voids. There is. Furthermore, since the temperature at which thermal contraction starts is as low as about 100° C., the pressing force acts almost synchronously with the decrease in the viscosity of the resin. In addition, since it contracts at low temperatures, it has the versatility to be applied to a wide range of insulation methods, including not only H type, but also B and F types.

The electrically insulated wire shaft obtained in this way has a dielectric breakdown strength of 29
It is high at over kV/mm and also meets the American standard IEEE standard.
.

Heat resistance life is 180° due to motor talent according to 275.
It was 100,000 hours or more in C, and had H class heat resistance.

Example 2 A prepreg mica tape with the following configuration was prepared.

Laminated mica sheet with Kapton film (product name of DuPont) as backing material, 30 parts by weight of Epikot 152 (product name of Shell Chemicals), 60 parts by weight of Epikot 154 (product name of Shell Chemicals), Epicoat 1001 (product of Shell Chemicals) 10 parts by weight of methylnadic anhydride (manufactured by Nippon Kayaku Co., Ltd.), 2 parts by weight of aluminum acetylacetonate (manufactured by Yoken Fine Chemicals Co., Ltd.), 3 parts by weight of shefnyl jetoxysilane (manufactured by Toshiba Silicone Co., Ltd.) It was impregnated with 45% by weight of a heat-resistant resin made by blending parts by weight. This pre-preg mica tape is wound around a conductor by a predetermined number of 172 turns to form an insulating layer (2). A heat-shrinkable polyimide film tape is wound once on the insulating layer with 172 turns to provide a resin leakage prevention layer (3). This wire ring is housed in an iron core, and the wire connection portion is also provided with an insulating layer and a resin leakage prevention layer (3) similar to those described above. The entire core is heated at 150° C. for 15 hours to harden the insulating layer and shrink the heat-shrinkable polyimide film to obtain a dense electrically insulated wire shaft.

According to this manufacturing method, an insulated wire ring with class H heat resistance can be easily obtained without any equipment such as a molding device. 6 Another effect of wrapping the heat-shrinkable polyimide film tape is that the surface of the wire wire is smooth. This makes it easier for cooling air to pass through the equipment, thereby suppressing abnormal temperature rises. Furthermore, as mentioned above, since a film with an extremely high dielectric breakdown voltage is used, it also contributes to an improvement in dielectric strength.

〔Effect of the invention〕

As explained above, according to the present invention, an insulating layer is formed on the surface of a wire-wound conductor, and a heat-shrinkable polyimide film tape is wrapped around the surface to form a resin leakage prevention layer. When the layer is impregnated with a thermosetting resin and then heated and cured, the resin leakage prevention layer is shrunk to form an insulating layer under pressure and at the same time prevent the resin from flowing out. Therefore, no harmful voids are created in the cured insulating layer, and the reliability is high.The insulating surface is smooth, so ventilation cooling is not obstructed.Furthermore, since the heat-shrinkable polyimide film tape is used, it is heat-resistant and has a class H heat resistance. This is a method for manufacturing an insulated A-ring.

[Brief explanation of drawings]

The drawing is a sectional view of an electrically insulated wire ring manufactured by an embodiment of the method of the present invention. 1. Winding conductor, 2. Insulating layer, 3. Resin leakage prevention layer.

Claims (1)

[Claims] In a method for manufacturing electrical insulating wire by a vacuum pressure impregnation method or a resin-rich method, an uncured thermosetting resin is added to the outside of the insulating layer by winding an insulating tape that is pre-impregnated with the resin, or A resin leak prevention layer is formed by heavily winding a heat-shrinkable polyimide film tape or sheet, and is heated to shrink the resin leak prevention layer and harden the resin in the insulating layer. A method for manufacturing electrically insulated coils.