JPS6222246B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an impregnated resin molded coil for use in a dry transformer.

Recently, molded transformers in which coils are molded with resin have appeared in the field of dry type transformers. To manufacture resin molded coils for molded transformers, there are two methods: placing the coil in a mold, then casting and curing the molding resin (mold type), and immersing the entire coil in impregnated resin to form the resin. After impregnation,
There is a method (impregnation type) in which the coil is taken out and hardened.

In the case of the impregnated type, since no extra resin layer is attached, there is no occurrence of cracks peculiar to molded coils, and the coil can be made smaller and lighter. Furthermore, since a low-viscosity resin can be used, the resin is well impregnated into the coil, the heat resistance of the resin is effectively exhibited, and a highly reliable molded coil can be obtained.

However, since a low-viscosity resin is used, the key to this manufacturing method is to cure the resin impregnated inside the coil without leaking it to the outside.

The conventional impregnation type manufacturing method is to take the coil out of the impregnation tank, place it in a rotating drive device, and blow hot air into it to harden it while rotating it.

Impregnate the inside of the coil or the coil insulator with a curing accelerator in advance, impregnate it with resin, and the curing accelerator and resin will react and gelation will proceed. When the resin stops leaking sufficiently, remove the coil. A method of taking it out and hardening it in a heating furnace.

It has been known. Regarding the manufacturing method of these,
The manufacturing method has attracted attention in recent years because it requires work to place the coil on a rotating device and is not suitable for mass-produced models due to equipment limitations of the rotating device.

In this conventional method, a coil is formed using an insulator that has been impregnated with a curing accelerator in the end insulator and outer insulator of the coil, and in this state, it is impregnated with resin in an impregnating tank (not shown) to cause gelation. Progressing temperature (80-90
℃), the insulating material impregnated with the curing accelerator will undergo gelation, and when the resin inside the coil is blocked by the gelled insulating layer and no longer drips even if the coil is pulled out of the impregnating bath, the coil will be removed. By taking it out and curing it in a heating furnace,
Get a coil.

However, the following drawbacks were found in this conventional manufacturing method. In other words, the end insulator and the outer insulator are pre-impregnated with a curing accelerator, so they gel quickly, but the interlayer insulator that is interposed between the layers of the conductor winding layer and protrudes from both ends needs to be treated with a curing accelerator. Since this was not done, there was a drawback that the impregnated resin would flow out through the interlayer insulator. Another method is to treat the interlayer insulation with a curing accelerator, but the curing accelerator has the disadvantage of worsening the insulation performance between the coil layers, so a method in which a large amount of curing accelerator is distributed within the coil is not recommended. Undesirable. That is, in FIG. 1, imidazole is used as a curing accelerator.
1B2MZ (hardening accelerator manufactured by Shikoku Kasei Co., Ltd.: trade name) is dissolved in ethyl alcohol, and the temperature characteristics of tan δ between the coil layers after resin molding are shown as a function of the concentration of the solution. As is clear from this figure, tan δ increases as the concentration of the curing accelerator solution increases, so the method of treating the curing accelerator inside the coil tends to cause rapid thermal deterioration of the resin and cause insulation defects.

The present invention was made to eliminate these drawbacks, and it is possible to cure the impregnated resin without impairing the impregnating properties of the resin and without leaking.
It is an object of the present invention to provide a method for manufacturing a resin molded coil that does not reduce insulation performance.

Hereinafter, a method for manufacturing a resin molded coil according to the present invention will be explained with reference to FIGS. 2 to 5. 2 and 3 are a plan view and a partial cross-sectional view of a cylindrical coil according to the manufacturing method of the present invention. First, a secondary conductor 2 is wound on a winding frame 1, and end insulators are attached to both axial ends of the secondary conductor 2. 3 is provided, and a glass cloth tape is wound around the outer periphery to provide an outer periphery insulator 4 to form a secondary coil. This outer insulator 4 is pre-impregnated with a curing accelerator; for example, glass cloth tape is mixed with imidazole 1B2MZ in ethyl alcohol at a ratio of 10:9.
It is possible to use a product that has been impregnated with a solution dissolved at a ratio of 1 and then dried. Next, a wave-shaped spacing insulator 5 is placed around the outer periphery of the outer insulator 4 to form a cooling duct, and a primary coil is formed around the outer periphery. The primary coil is formed by winding the glass cloth tape impregnated with a hardening accelerator as the inner insulator 6 in the same way as the outer insulator 4 described above, and the primary conductor 7 is attached to the outer periphery of the tape with an interlayer insulator 8 interposed therebetween. An end insulator 9 is provided at both axial ends of each wound layer, and a glass cloth tape impregnated with a curing accelerator is wound around the outermost periphery in the same manner as the outer insulator 4 to form an outer insulator. 10 is provided. The end insulators 3 and 9 provided at both axial ends of each coil are made of aromatic polyamide nonwoven fabric (for example, manufactured by Nippon Vilene).
HC5408), asbestos, mineral fiber board (product name: MF Sheet), etc., with good resin impregnation properties. The end insulators 3 and 9 are not previously impregnated with a curing accelerator. Also, the interlayer insulator 8 is not impregnated with a hardening accelerator.

Next, as shown in FIG. 4, the coil body 11 formed in this manner is heated to a solution 12 of imidazole 1B2MZ, a hardening accelerator, dissolved in ethyl alcohol at a ratio of 10:90.
and immersed in the solution 12 to a height that the lower end insulators of each of the primary and secondary coils are immersed. This immersion time may be about several minutes. After the lower end insulator and the lower end of the interlayer insulator are sufficiently impregnated with the curing accelerator, the coil body 11 is taken out and dried in a drying oven by removing the solvent.

The dried coil body 11 is carried into a vacuum tank 14 as shown in FIG. Processing viscosity is approx.
100 cp) and immerse the coil body 11 in this impregnation tank 15 to apply the resin to the coil body 11.
Impregnate inside. The temperature of the impregnated resin 16 is set to a temperature at which the resin reacts with a curing accelerator impregnated into the lower end insulator, inner and outer peripheral insulators, etc., which will be described later.

Here, the resin 12 is quickly impregnated through the outer and inner insulators 4 and 6 located on the upper and lower end surfaces of each coil, the inner and outer circumferential surfaces of the cooling duct, and the outer insulator 10 of the primary coil. And the lower end insulators 3 and 9
Since the lower end of the interlayer insulator 8 and the inner and outer peripheral insulators 4, 6, and 10 wound around the inner and outer peripheral surfaces of the coil are impregnated with a curing accelerator, the resin and the curing accelerator react with each other. Begins to gel. The resin in the gelled lower end insulators 3 and 9 of the coil, the lower end of the interlayer insulator 8, and the inner and outer insulators 4, 6, and 10 exactly covered the bottom and inner and outer peripheries of each coil, including the winding frame. Since a container is formed, if the coil body 11 is taken out from the impregnation bath 15 at this point, each coil will be impregnated with uncured resin, and the uncured resin can be taken out without leaking from the coil. can. Then, this coil body 11 is housed as it is in a heating furnace (not shown) and heated, and the uncured resin inside the coil is completely cured to obtain a resin molded coil.

In this way, during impregnation, the resin can be impregnated into the coil through the upper and lower end surfaces of each coil, the inner and outer peripheral surfaces of the cooling duct, and the outermost peripheral surface, so that the resin can be completely impregnated into the coil without forming any unimpregnated parts inside the coil. It can be impregnated with. Moreover, even if the resin shrinks when it gels, the upper end of the coil is an area that is not impregnated with the curing accelerator, and since the resin is supplied through this area, the resin can be impregnated without creating voids inside each coil. . In addition, the lower end insulators 3 and 9 of the coil,
The lower end and inner part of the interlayer insulator 8, the outer peripheral insulator 4,
Since the gelled resin in 6 and 10 forms a container using the constituent materials of the coil body 11, it has relatively high mechanical strength and cannot be heated when the coil body 11 is taken out or in a heating furnace. Prevents resin from leaking from inside the coil during the process. Furthermore, the insulating coating of the conductor and the interlayer insulation in the vicinity are not impregnated with a curing accelerator, and even if some curing accelerator impregnated in the inner and outer peripheral insulators 4, 6, and 10 is contained in the resin, this The section is a section that is cooled by air, and thermal deterioration is suppressed, so that the insulation performance between the coil layers does not deteriorate. Further, since a resin having a low viscosity of about 100 cp can be used, effects such as being able to shorten the time required for pressure treatment after vacuum impregnation can be obtained.

In the above example, the impregnating resin was heated to a constant temperature as a means for causing the reaction between the impregnating resin and the curing accelerator. A similar effect can be obtained by holding the reaction at a constant temperature.

As described above, according to the present invention, it is possible to impregnate a coil with a low viscosity impregnating resin, and further,
In this case, without creating unimpregnated voids in the coil and without being affected by the curing accelerator,
A resin molded coil with excellent electrical and mechanical properties can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the concentration of the curing accelerator and the temperature characteristics of tan δ between the coil layers after resin molding, and Figs. 2 and 3 are plane views showing the state during manufacturing of the resin molded coil in the manufacturing method of the present invention. The drawings, partial sectional views, and FIGS. 4 and 5 are side views showing each step of the manufacturing method of the present invention. DESCRIPTION OF SYMBOLS 1... Winding frame, 2... Secondary conductor, 3... End insulator, 4... Perimeter insulator, 5... Spacing insulator, 6...
... Inner circumference insulator, 7 ... Primary conductor, 8 ... Interlayer insulator, 9 ... End insulator, 10 ... Outer circumference insulator, 1
1... Coil element body, 12... Hardening accelerator solution, 1
3... Container, 14... Vacuum tank, 15... Resin impregnation tank, 16... Impregnated resin.

Claims (1)

[Claims] 1. A secondary conductor is wound in a cylindrical shape on a winding frame, and end insulators made of an insulator with good resin impregnation property are provided at the upper and lower ends of the wound layer, and the outer periphery is made of an insulator with good resin impregnation property. A secondary coil is provided with an outer insulator made of an insulator with good properties, and an inner insulator made of an insulator with good resin impregnation is provided on the outside of the outer insulator of this secondary coil via a spacer insulator. The primary conductor is wound in multiple layers in a cylindrical shape on this inner insulator through an interlayer insulator made of an insulator with good resin impregnation properties, and the upper and lower ends of each winding layer are coated with an insulator with good resin impregnation properties. When forming a coil body consisting of a primary coil which is provided with an end insulator and an outer circumferential insulator made of an insulator with good resin impregnation properties on the outer periphery, only the inner and outer circumferential insulators are coated with a curing accelerator. The impregnated insulator is wound and formed, and after forming the coil body, the lower end of each coil is immersed in a hardening accelerator solution dissolved in a solvent, and then dried. The coil body is then stored in a resin impregnation tank and impregnated with resin.
When the resin impregnated into the lower end of the inner and outer peripheral insulators, the lower end insulator, and the interlayer insulator reacts with the curing accelerator and gels, the coil is taken out from the resin impregnation tank and impregnated into the coil. A method for manufacturing a resin molded coil, which method comprises curing a molded resin. 2. The method for manufacturing a resin molded coil according to claim 1, wherein the end insulator is formed of an insulator with good resin impregnation properties such as aromatic polyamide nonwoven fabric, asbestos, mineral fiber board, glass cloth tape, etc.