JPS60177513A - Mold bushing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a molded bushing, and particularly to a molded bushing that alleviates electric field concentration at the back of an electrode arranged concentrically around the outer periphery of a center conductor. .

[Prior art]

FIG. 1 is a side sectional view showing a conventional molded bushing. In the diagram @
and are arranged. The insulating member (2) provides interlayer insulation between the electrodes (3), and is made of insulating paper, synthetic fiber such as Tetron nonwoven fabric, glass fiber, etc. as an impregnated base material for interlayer insulation. The electrode (3) is made of aluminum foil, for example, and has a plurality of concentric layers. The capacitor is constructed by placing the capacitor on the capacitor. The impregnating resin (4) is, for example, an epoxy resin, and the central conductor (1) and the insulating member (
2) and the electrode (3) are integrally molded.

Next, a method for manufacturing the molded bushing shown in FIG. 1 will be explained. Band-shaped insulating members (2) and electrodes (3) are alternately wound around the outer periphery of the center conductor (1) to form a capacitor core, the solid capacitor core is set in a mold, and the impregnated resin ( 4) are vacuum impregnated and integrated to form the molded bushing shown in FIG.

In this case, in order to improve the impregnating property of the impregnating resin (4), the interfacial phase between the impregnating resin (4) and the electrode (3) is treated with an adhesive such as an oxyresin.

Conventional molded bushings are constructed as described above, and when used in a high 11 voltage circuit, a large electric field concentration occurs at both ends of the electrode (3), resulting in poor withstand voltage characteristics and shortened lifespan. There was a drawback that reliability decreased. Furthermore, in order to improve these drawbacks, the insulation thickness was increased more than necessary, resulting in a larger shape. Furthermore, due to curing reaction shrinkage after resin impregnation, temperature rise during actual use, or thermal stress due to environmental temperature changes, peeling or cracking occurs at the end of the electrode (3), resulting in corona defects. .

[Summary of the Invention] This invention has been made to eliminate the drawbacks of the conventional ones as described above, and by providing electrode relaxation members at both ends of the electrode (3), it is possible to The purpose of this invention is to provide a molded bushing that can alleviate electric field concentration.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

A symbol is attached. In Fig. 2, the electric field relaxation member (5
) is, for example, semiconductive mixed paper Coronox (Westinghouse Co., Ltd.) made of insulating paper and carbon powder.
), an electric field relaxation member (6) made of, for example, Coronox tape is pasted with a conductive adhesive to both ends of the electrode (
3) are alternately wound around the outer periphery of the center conductor (1) to form a capacitor core, this capacitor core is set in a mold, and the impregnated resin (4) is vacuum impregnated and integrated.
The molded bushing shown in FIG. 2 is constructed. In this case, Colonox tape with a thickness of 0.02 mm is placed on both ends of the electrode (3) so that the ends of the electrode (3) are not exposed.

In the above example, Colonox tape was used as the electric field relaxation member (6), but any semiconductive material sold on the market can be used, such as a mixed paper made of polyester fiber and carbon fiber. be. Further, a conductive member may be used as long as it can relax the electric field better than aluminum foil.

〔Effect of the invention〕

As described above, according to the present invention, since electric field relaxation members are provided at both ends of the electrode, the drop in withstand voltage due to electric field concentration at the electrode ends is improved, high voltage is possible, reliability is improved, and compactness is achieved. This has various effects such as making it possible to

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a conventional molded bushing, and FIG. 2 is a side sectional view showing an embodiment of the molded bushing according to Jin's invention. In the figure, (1) is the center conductor, (2) is the insulating member, (
3) is an electrode, (4) is an impregnated resin, and (5) is an electric field relaxation member. Note that the same reference numerals in each figure indicate the same parts. Agent: Masuo Oiwa, Patent Attorney Figure 1 Figure 2

Claims (3)

[Claims] (1) Insulating members and electrodes arranged concentrically and alternately with the center conductor at outer stations of the center conductor, and electric field relaxation members provided on both sides of the electrodes, the center conductor and the insulating member A molded bushing, wherein the electrode and the electric field relaxation member are integrally molded using an impregnated resin. (2) The molded bushing according to claim (1), wherein the electric field relaxation member is made of paper or a mixed paper made of synthetic fiber and a conductive material. (3) The molded bushing according to claim (2), wherein the conductive material is carbon.