JPH0233912A - Method of impregnating electric apparatus with insulating material - Google Patents

Abstract

PURPOSE:To improve the electric characteristics and reduce the variation of the electrical characteristics by a method wherein, after an electric apparatus is impregnated with insulating material under vacuum, the insulating material is made to penetrate sufficiently into the inside of the electric apparatus main part and the inside of the electric apparatus is sufficiently impregnated with the insulating material in a vacuum holding process. CONSTITUTION:An electric apparatus main part 1 is placed in a die or container 2 and the die or container 2 is housed in an impregnating chamber 3 and the chamber 3 is housed in a thermostatic oven 4 and a vacuum valve 9 is opened to subject the main part 1 to a vacuum heating treatment. A valve 8 is opened and impregnating resin 6 processed beforehand is introduced into the chamber 3 through a pipe 7 to fill the chamber 3 and the main part 1 is impregnated with the resin 6. The valves 8 and 9 ara closed and the inside of the chamber 3 is held under vacuum for a certain time and then a valve 12 is opened to introduce the air into the chamber 3 and the resin 6 is cured by heat. With this constitution, the electrical characteristics can be improved and the variation of the electric characteristics can be reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for impregnating electrical equipment with insulation material.

[Conventional technology]

Some electrical devices such as capacitors, transformers, and current transformers are constructed by impregnating the main body of the electrical device with an insulating material such as an impregnating resin.

Conventionally, when impregnating such insulating materials, the main body of the electrical device is first set in a mold or container and subjected to a specified vacuum heat treatment, and then the pre-treated impregnation resin is vacuum filled and electrically heated. The main body of the device is impregnated, and then the pressure is returned to atmospheric pressure and the impregnating resin is cured by heat treatment, or after the impregnating resin is vacuum filled, pressure treatment is performed by applying pressure using N2 gas etc. for a certain period of time. After that, the impregnating resin was heat-cured by heat treatment.

For example, in capacitors, epoxy resin is used as the impregnating resin, and this epoxy resin is used not only as a dielectric material together with a wound dielectric film, but also as an exterior body of the capacitor to form a molded capacitor.

[Problem that the invention seeks to solve]

However, according to the above-mentioned impregnation method, the impregnation resin is insufficiently impregnated into the main body of the electric device, so that desired electrical characteristics cannot be obtained.

The reason for this is that although the area around the electrical equipment body can be impregnated in a short time by vacuum filling the impregnating resin, the gap inside the electrical equipment body is extremely small, and the viscosity of the impregnating resin is high. The impregnating resin cannot penetrate and impregnate the gap in the electrical equipment main body that should be impregnated, and the core remains as an unimpregnated part.In this state, when it is exposed to atmospheric pressure and heat-treated, the unimpregnated part Even if the impregnating resin is heated and cured with the impregnating resin remaining in the core, or even if pressure treatment is applied after vacuum filling, the gaps in the unimpregnated parts inside the electrical equipment are crushed by the pressure, preventing the impregnating resin from penetrating into the core. Impregnation becomes more difficult and unimpregnated portions remain, which is considered to be a factor in increasing variations in electrical characteristics and deteriorating characteristics.

Taking the molded capacitor as an example, as shown in FIG. 6(a), the end of the capacitor element a can be impregnated in a short time by vacuum filling with the impregnating resin. It takes a long time to permeate and impregnate the resin, and if the unimpregnated portion d is left inside and placed under atmospheric pressure or pressurized state, the unimpregnated portion d will be in a vacuum state. As shown in b), the dielectric films C come into close contact with each other, making it difficult to penetrate and impregnate the core with m and llIb.

In view of the above-mentioned points, it is an object of the present invention to provide a method for impregnating an insulating material for an electrical device, which can sufficiently impregnate the inside of the main body of the electrical device and has excellent electrical properties such as insulation properties.

[Means for solving problems]

The present invention is characterized in that the insulating material is sufficiently permeated and impregnated into the inside of the electrical equipment body by vacuum-holding the electrical equipment body after filling the electrical equipment body with the insulating material.

〔Example〕

Embodiments of the present invention will be described below with reference to an impregnating apparatus shown in FIG.

In the figure, 1 is the main body of the electrical equipment to be impregnated, 2 is the mold or container, 6 is the impregnation chamber 4 is a constant temperature bath, 5
is a tank containing impregnating resin 6. The impregnation chamber 6 is connected to the tank 5 via a vibrator 7 and a pipe 7
A pipe 11.1 is equipped with a resin filling valve 8, and a vacuum valve and an air injection valve 10.
2 are connected. Note that 16 is a vacuum pump.

Next, we will explain the impregnation method using this impregnation device.First, as shown in the figure, the electrical equipment main body 1 is set in a mold or container 2, and this is housed in the impregnation chamber 6. The chamber 6 is housed in the constant temperature bath 4, the vacuum valve 9 is opened, and the electrical equipment main body 1 is subjected to a predetermined vacuum heat treatment. Then, the valve 8 is opened, and the previously treated impregnating resin 6 is vacuum-filled into the impregnating chamber 6 via the vibrator 7, and impregnated into the electric device main body 1 set in the mold or container 2. Thereafter, the valves 8 and 9 are closed to maintain a vacuum in the co-immersion chamber 6 for a certain period of time, and after this vacuum hold, the valve 12 is opened to inject air into the impregnation chamber 6 to maintain the impregnating resin at atmospheric pressure. 6 is heated and cured.

According to experiments conducted by the present inventors, results as shown in FIG. 2 were obtained.

Figure 2 shows the partial discharge inception voltage (D
IV) was measured and plotted, and in both cases the epoxy resin (100 CPS: at 40
°C) and vacuum filled.

In the figure, (5) shows the DIV value after vacuum filling with epoxy resin according to the present invention, holding the vacuum at 1 to 3 Torr for about 24 hours, and then leaving it at atmospheric pressure for about 24 hours. Also, shi) is about 48% at weather pressure after vacuum filling with resin.
The DIV value after leaving Hrs and C) is about 4Kgf/c after vacuum filling with resin! Approximately 24Hr at a pressure of Il'
s DIV after pressurizing and then leaving at atmospheric pressure for 24 hours
Show value.

As is clear from the figure, it was confirmed that the DIV value was higher when the impregnating resin was vacuum-filled and then held under vacuum compared to the one when treated at atmospheric pressure or under pressure, and the variation was also reduced. .

By holding the product in vacuum, the unimpregnated parts inside the electrical equipment body that have not been impregnated by vacuum filling with the impregnating resin are not crushed by atmospheric pressure or pressurization and are kept in almost the same state. This is thought to be because the resin does not penetrate and impregnate easily, and over time, the core part is penetrated and impregnated, and the unimpregnated part becomes small or disappears.

It goes without saying that the insulating material used in the present invention may be, in addition to the above-mentioned epoxy resin, for example, polyurethane resin, insulating varnish, or even insulating oil.

〔Effect of the invention〕

As explained above, according to the present invention, the insulating material can be impregnated into the inside of the electrical equipment body, and the electrical characteristics can be improved compared to the conventional ones, and variations in the electrical characteristics can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an impregnating apparatus used to explain the present invention in detail, Fig. 2 is a characteristic diagram showing the experimental results of the present invention, and Fig. 6 (a), (tJ indicates a conventional example). 1: Main body of electric equipment, 2: Mold or container, 6: Chamber for impregnation, 6: Resin for impregnation. (A)... Partial discharge inception voltage of the molded capacitor according to the present invention (B , C)...Partial discharge start voltage of the molded capacitor according to the conventional example.

Claims (1)

[Claims] In an insulating material impregnation method for impregnating an electrical equipment main body with an insulating material, the electrical equipment main body is subjected to a predetermined vacuum heat treatment, and then the insulating material is vacuum filled, and after the vacuum filling of the insulating material, a vacuum hold is performed. A method of impregnating an electrical device with an insulating material, the method comprising: