JPS59197473A - Electric field relaxing paint and electric field relaxing material - Google Patents

Abstract

PURPOSE:To provide the titled paint which is insoluble in insulating varnish and has a high electric field-relaxing effect, consisting of a specified modified polybutadiene resin and silicon carbide powder. CONSTITUTION:A polymn. initiator, a hardener and silicon carbide powder are blended with an acrylic-modified, allyl-modified or epoxy-modified polybutadiene resin of formula I , II or III. The mixture is dissolved in a solvent to obtain an electric field-relaxing paint. A sheet-form or tape-form fiber composed of glass fiber or an org. fiber is coated with or immersed in said point to obtain an electric field-relaxing material. EFFECT:Since visible corona starting voltage is high, an electric field-relaxing material excellent in corona deterioration can be obtd. USE:Rotor of a rotary machine, coil end, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electric field-relaxing coating used for stator coil ends and the like of φi1 machines to which high voltage is applied; J3 and improvements to electric field-relaxing materials.

[Technical Background of the Invention and Problems Therewith] An electrostatic potential is generated on the surface of an electrically insulating layer covering a conductor under high voltage due to the induction of a current flowing through the conductor. When the gradient of the generated electrostatic potential reaches a certain level or higher, corona discharge occurs, and as a result, the surface of the insulating layer deteriorates and dielectric breakdown becomes more likely to occur. To prevent deterioration of the insulating layer due to such phenomena, paints containing graphite, carbon black, or silicon carbide powder (hereinafter referred to as SiC), iron-containing asbestos tape, and the like are generally used. In particular, since SiC-containing coatings exhibit non-linear resistance changes depending on applied voltage, they have the advantage of making the electrostatic potential gradient more uniform than other coatings. In recent years, iron-containing asbeth 1-Dave, which has been used to alleviate the electric field at the coil end of the stator of generators and motors, has been subject to pollution regulations. Alternatively, the use of the paint is increasing by impregnating and applying the paint to glass fiber, synthetic resin woven fabric, or Qi 1.

However, in the conventional electric field relaxation treatment that involves coating the SiC powder powder, it is applied directly to the coil by brushing and drying, but in order to obtain the necessary voltage-current characteristics, the brush coating and drying operation is repeated 3 to 4 times. It is necessary to cover the coating layer thickly, and the characteristics vary widely.
Therefore, SiC prepreg cloth (sheet) is a material that is easy to work with, has a homogeneous SiC layer, and has small variations in properties.
A method was devised in which the coil was wound with tape and cured under pressure. However, conventional SiC prepreg etc. cannot be dissolved in di-poxy insulation varnish used for coil insulation treatment. Therefore, the coil must be impregnated and heat-cured and then treated. Therefore, the coil heating treatment must be performed twice, which results in a disadvantage that the work cost is high.

SiC dry tape is one that does not dissolve in insulating varnish. This is a type of SiC that is made by applying and curing SiC coating to an Arp base material, and has flexibility. However, S
When iC dry tape is wound around a coil and impregnated with insulating varnish, it is easy for the insulating varnish to enter between the SiC tape layers. It is difficult to homogenize the SaC layer, the electric field relaxation effect is inferior to the prepreg type, and it is difficult to use for high voltage coils. However, there was a drawback that the electric field relaxation property was not sufficient.

[Object of the Invention] The present invention was made in view of the above-mentioned problems, and provides an electric field relaxation paint that is not dissolved in an insulating varnish and has a large electric field relaxation effect, and work 1 ([a poor electric field relaxation l). It is an object.

[Summary of the Invention] As a result of extensive research to achieve the above object, the present invention discovered that polybutadiene resin is incompatible with solvent-free epoxy resin varnish, leading to the invention described below. It is.

That is, the present invention relates to an electric field relaxation paint whose main components are an acrylic-modified, allyl-modified or evogish-modified polybutadiene resin and silicon carbide powder, and an electric field relaxation paint obtained by impregnating and applying this paint to Sea 1 or a tape-shaped IJli string. It is a material.

The acrylic-modified, allyl-modified or epoxy-modified polybutadiene resin used in the present invention has the following structural formula (
Examples include those having I), (11), and (Ill).

... (I) ... (Tl) ... <m> Usually, acrylic-modified and miallyl-modified polybutadiene resins are used, but these resins have relatively small molecular weights,
If these are used as a relaxing material, they may be too sticky or
When the SiC layer is wound around a coil and hardened under pressure, the SiC layer may leak out to a large extent, and in order to improve this phenomenon, it is recommended to add a portion of epoxy-modified polybutadiene resin.
Examples of such resins include TE2000 (polybutadiene acrylate manufactured by Nippon Soda), E-1000 (
Kowa Polymer Polybutadiene Acrylate), EPB-
12B (Nippon Soda Boriv, Kudiene Epoxy), and the like.

As the silicon carbide powder (1B) used in the present invention, ordinary ones are used, and there are no particular restrictions on the particle size, and various types can be used depending on the purpose. For example, there is silicon carbide powder made by Shinano Denki Smelting Co., Ltd.

Further, as the sheet- or tape-shaped fibers used in the present invention, porous substrates such as glass fibers, organic fibers, glass non-woven fabrics, organic fiber non-woven fabrics, and plastic films are used.

The main components of the electric field relaxation paint of the present invention are acrylic-modified, allyl-modified or epoxy-modified polybutadiene resin and carbon dioxide powder, but in addition to these, curing agents, curing accelerators, solvents, etc. may be added as necessary. can.

The paint is manufactured by blending a modified polybutadiene resin, a polymerization initiator, a curing agent, and silicon carbide powder, mixing well, and dissolving in a solvent. Further, the electric field moderating material can be obtained by impregnating and coating a sheet or tape-shaped fiber with the above-mentioned coating material by a spraying method, dipping method, or the like.

[Embodiments of the invention] Examples of the present invention will be described below.

Examples 1 to 3 An electric field relaxation paint having the composition shown in Table 1 was produced, and the resulting paint was passed through a 0.4 mm slitter through a glass tape having a thickness of 0.13 mm and a width of 25 mm, and was coated with C. 1
Drying was performed at 00° C. for 10 minutes to obtain an electric field relaxation material. The tackiness, solubility, and visible corona onset voltage were measured for these relaxations (A') and are shown in Table 2.

In addition, the relaxation moon was wound around the model T1 coil, and then impregnated with insulating varnish (a> and the one not impregnated (b)
) was measured and shown in Figure 1.

From Tables 1 and 2 and FIG. 1, it was confirmed that the electric field mitigation coating and material of the present invention were excellent.

[Effects of the Invention] As can be seen from the above explanation, the paint according to the present invention is not dissolved in other insulating varnishes, has good workability even when used as a relaxation material instead of impregnating fibers with the paint, and does not cause the onset of visible corona. It can be seen that because the voltage is high, it is excellent in corona deterioration.

[Brief explanation of the drawing]

FIG. 11 is a diagram showing the surface resistivities of Examples and Comparative Examples. Patent applicant: Toshiba Chemical Corporation

Claims (1)

[Scope of Claims] 1. An electric field relaxation paint whose main components are an acrylic-modified, allyl-modified or epoxy-modified polybutadiene resin and silicon carbide powder. 2. Electric field relaxation tA, which is obtained by impregnating and applying an electric field relaxation paint mainly composed of an acrylic-modified, allyl-modified or epoxy-modified polybutadiene resin and silicon carbide powder to a tape-shaped fiber.