JPS61166010A - Electrically insulated coil - Google Patents

Abstract

PURPOSE:To obtain electrically insulated coil which has high content of mica, good texture thereof, and superior characteristics in thermal, electrical, and mechanical aspeets, by winding the insulative sheet or insulative tape formed by fusing the aramid-blended mica paper and aramid paper or the coil and hardening after impregnation with the thermosetting resin. CONSTITUTION:The mica sheet formed by fusing the aramid-blended mica paper and aramid paper are dipped in the diluted solution of which the siloxane compound SH containing the hydroxyl group to promote the hardening of impregnated resin and the alminum-triacetyl acetonate are dissolved into the methyl-ethyl-keton, and are dried. Thus the SH and the alminum-triacetyl- acetonate are contained in the mica sheet which is cut and made up into the mica tape as the insulation material. This mica tape is wound on the coil 13 turns of the 1/2 lapped winding, and inserted into the dummy core which is accommodated in the impregnating tank. After the pressure in the tank is reduced, the resin composition is sent-in and the pressure is impressed. Finally the object is taken out from the impregnating tank and is hardened by heat in the oven.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electrically insulated coil having excellent electrical, thermal, and mechanical properties and particularly suitable for use in high-voltage rotating machines.

[Technical background of the invention and its problems] High-voltage AC motors, industrial DC machines, water turbine generators, turbine generators, and the like are becoming increasingly high-voltage and large-capacity as the capacity of each unit increases. Along with this, efforts have been made to increase the operating temperature and operating electric field, and to reduce the size of machines. To this end, the electrically insulated wire wheels used in these machines must have thermal, electrical, and mechanical properties such as heat resistance and voltage resistance.
It is essential to improve i.

Insulation for these machines has traditionally been achieved by wrapping mica tape, which is made by bonding reinforcing materials such as paper, film, glass woven fabric, or polyester nonwoven fabric, with adhesive to peelable mica or laminated mica, and filling the voids in these base materials with epoxy, polyester, This was done by filling it with a resin such as polyimide and curing it. There are two ways to fill the resin: wrapping a mica tape containing a small amount of adhesive and then impregnating it with resin under vacuum pressure (vacuum pressure impregnation method), and adding an appropriate amount of adhesive into the mica tape in advance. There are two methods (prepreg method or resin rich method). In general, in order to obtain electrically insulating wire with excellent thermal, electrical, and mechanical properties, it is necessary to increase the mica content in the insulating layer and to improve the formation of mica.
It is necessary to have good compatibility between the adhesive, the impregnating resin, and the reinforcing material. However, with conventional mica tapes, the only adhesive between mica is the weak adhesive force of crystallized water, so the density is low and the mica layers easily peel off.
Furthermore, when the mica tape is wound around a coil, mica pieces may fly off, so the mica tape must contain more adhesive than necessary. For this reason, it has been difficult to increase the mica content in the insulating layer, to improve the impregnating property in the case of a vacuum pressure impregnation method, and to improve the compatibility between the adhesive and the impregnated resin. In addition, with conventional mica tapes, when pressure is applied to the insulating layer and the insulation layer is heated and cured, the mica layer tends to flow, causing a decrease in edge coverage, and the mica tape tends to become thicker due to the thinner edges. Because the adhesive present in the mica tape migrates toward the mica and reinforcing material during storage, the mica sometimes separates from the reinforcing material during taping, causing problems.

[Purpose of the invention]

The present invention was made to solve these conventional problems, and by using a mica tape in which reinforcing material and mica are bonded together without using an adhesive, the impregnability and compatibility caused by the adhesive can be improved. Thermal and electrical properties with high mica content and good mica formation have no problem with properties, and the mica does not easily scatter or fall off during taping, has excellent winding workability, and is less likely to cause laminar flow. The purpose is to provide mechanically superior electrical insulating wire wheels.

[Summary of the invention]

7 Lamid fibrids have an extremely high mica capture effect (
Special Publication Showa 43-20421>. The present invention utilizes this fact to heat aramid-mixed mica paper and aramid paper, which are wet-formed by mixing a very small amount of fibrids (several percent by weight) with mica, using a thermal calendar without using an adhesive. The mica sheet or mica tape is wound around a wire ring, impregnated with thermosetting resin, and cured to create an electrically insulating wire ring.

[Embodiments of the invention]

Next, examples of the present invention will be described.

Example 1 As epoxy resins, alicyclic epoxy resins Chissonox 221 (trade name, Chisso Co., Ltd.) and Shodyne 540 were used.
(Product name, Showa Denko Co., Ltd.), Bisphenol F type epoxy resin Ebicuron 830 (Product name, Dainippon Ink Co., Ltd.),
Bisphenol A type epoxy resin DER332 (trade name, Dow Chemical Company), Epiclon B5 as acid anhydride
70 (trade name, Dainippon Ink Co., Ltd.) in the proportions shown in Table 1, resin compositions a to d were prepared as an impregnating resin.

Table 1 These resin compositions ad are all characterized by low viscosity and long pot life.

Apart from this, 160g# aramid mixed mica paper,
25- A mica sheet made by heating and melting 1 liter of thick aramid paper is pre-treated with a hydroxyl group-containing siloxane compound 5H601B (trade name, Toshi Silicone Co., Ltd.) and aluminum triacetylacetate to accelerate the hardening of the impregnated resin. After dipping in a diluted solution of 5H6018 and aluminum triacetylacetonate in methyl ethyl ketone, 5H6018 and aluminum triacetylacetonate were each added to a mica sheet.
．． Contains 2% type set and 0.1%. This is cut into tape shapes to obtain mica tape, which is an insulating base material.

Although this tape contained almost no adhesive, there was no scattering of mica during tape winding, and because it was mixed with Soy 1 Lid, the mica paper had strength and elongation, and had excellent winding workability.

Then, this mica tape was wrapped 172 times around a wire ring 13 times, placed in a simulated iron core (not shown), and placed together with the iron core in an impregnating tank. After reducing the pressure at 1IrmlHg for 5 hours, the resin compositions a to d shown in Table 1 were introduced under reduced pressure to give 5ffy/C.
I! After pressurizing (gauge pressure) for 10 hours, it was taken out from the impregnation tank and heated and cured in an oven at 150°C for 15 hours to obtain an electrically insulated wire ring.

The obtained insulated wire ring had no problems with laminar flow of mica or cut-through at some corners, and the formation of mica was good.

Table 2 shows the results of measuring the tan δ (dielectric loss tangent) of these electrically insulated coils at 155° C. and a voltage of 11 KV/mm.

Table 2 According to Table 2, the maximum tan δ is 5.5%, and it can be seen that the dielectric loss is extremely small in all cases. In addition, these electrically insulated wire rings are all rated at 20KV/155°C.
It showed a dielectric breakdown voltage as high as mm. The bending strength at roughly 155°C is also 5! J/7 or higher, it was perfect as an insulated wire ring. When the insulating layer was disassembled, it was found that the resin was completely impregnated into the insulating layer, indicating that there was no problem with the impregnation.

Example 2 The mica sheet described in Example 1 was treated with DER431 (trade name, Dow Chemical Company) 100, an epoxy resin obtained from phenol formaldehyde novolak.
Parts by weight, 2 parts by weight of 5H601B (mentioned above), and 1 part by weight of aluminum triacetylacetonate were immersed in a solution in which methyl ethyl ketone was dissolved, and then dried to contain 10% by weight of the mica tape adhesive. This is cut into tape shapes to obtain mica tape, which is an insulating base material. This mica tape was more flexible than that of Example 1 and had good winding properties.

Then, this mica tape was wound around a coil in the same manner as in Example 1, and an electrically insulating coil was obtained in the same manner as in Example 1 using the resin composition C in Table 1.

This electrically insulated coil had a tan δ of 2% or less at 155°C and a high dielectric breakdown voltage of 25 KV/mm.
It can be seen that the characteristics are further improved compared to 1.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings; for example, the type and amount of the adhesive in the insulating base material are not particularly limited, and other modifications may be made without changing the gist thereof. Of course, it can be implemented with various modifications.

〔Effect of the invention〕

As described above, the electrical insulating wire according to the present invention is made by winding the attached insulating sheet or tape around the wire and impregnating it with thermosetting resin and hardening it, so that it is thermally, electrically and mechanically In addition to its excellent characteristics, it can be supplied at a lower cost than conventional wire wheels, so it can greatly contribute to higher electric fields and higher temperature operation of rotating machines.

Claims (1)

[Claims] An electrically insulating wire ring characterized in that an insulating sheet or insulating tape made by heat-sealing aramid-mixed macaque paper and aramid paper is wound around a wire ring, and then impregnated with a thermosetting resin and cured.