JPH02151247A - Manufacture of coil for electrical rotary machine - Google Patents

Abstract

PURPOSE:To prevent occurrence of corona by covering the vicinity of a damaged portion of a strand insulator with prepreg insulating material and making the upper and under faces of conductor semi-conductive thereby containing sealed micro-voids in the conductor. CONSTITUTION:A prepreg fiber material 2 composed of fiber insulating material applied with thermosetting resin is inserted between rows of strand groups where strands 1 are combined in Roebel transposition, and an inorganic anti- shortcircuit insulating material 3 is inserted between a transposition strand 1a and other strand 1. A prepreg insulating material 4a composed of fiber insulating material applied with thermosetting resin by 2/4-3/4 of the overall thickness of an insulating base body 4 is buried in a recess provided through transposition. Then a semi-setting insulating material 4b composed of fiber insulating material applied with inorganic semi-conductive material and thermosetting resin by 1/4-2/4 of the overall thickness of the insulating material is laminated thereon across the upper section of the transposition strand 1a. Then it is formed by a metal dies thus producing a coil conductor. By such arrangement, generation of corona from a void in the conductor can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a method for manufacturing a coil for a rotating electric machine in which conductor strands are subjected to Lebel transposition.

(Conventional technology) Large capacity like turbine generators and water wheel generators.

The coils of high-voltage rotating electric machines often use Lebel transposition of conductor strands. When this Lebel transposition is carried out, as shown in FIG. 2, an uneven portion is formed between the strand 2 and the transposed strand (1a). In addition, since the strands alone are easily deformed and cause problems in winding the insulating tape, adhesive varnishes or smoothing compounds are used to bond the strands together, fill in the recesses, and smooth the surface of the conductor. ing. In insulating coils for high-voltage rotating electrical machines, efforts are being made to create a layer with as few voids as possible, in other words, to prevent corona discharge inside the insulating layer, to the extent that there are no gaps in practical use.

(1) Dry laminated mica A vacuum pressure impregnation method in which the tape is wound a predetermined number of times, then impregnated with thermosetting resin under vacuum pressure, and then heated and molded.

(■) Vacuum prepreg method, which is obtained by winding a pre-preg assembly mica tape containing a large amount of thermosetting resin a predetermined number of times, followed by vacuuming, heating, and pressurization.

Two methods have been adopted.

Conductors molded and manufactured using conventional methods such as varnish or compounds cannot completely fill the internal voids, and as a result, even if the manufacturing process of the mica tape insulation applied as the ground insulation layer is perfect, the conductor's element If there is a gap between the wires, corona will occur during actual use of coil insulation, which will ultimately lead to a decline in insulation performance.

In order to prevent the above-mentioned deterioration of insulation performance, a method of filling dislocations, particularly recesses, with a semiconductive prepreg insulating material has begun to be adopted.

(Problem to be Solved by the Invention) However, the insulation of the wire covering at the portion bent at an acute angle at the wire dislocation portion is damaged. When the number of damaged parts of the wire insulation increases, a problem arises in that a circulating current flows through the semiconductive portion of the recess as a medium and the coil insulation generates heat.

SUMMARY OF THE INVENTION An object of the present invention is to provide an insulated coil that can eliminate the above-mentioned drawbacks, and to provide a method for manufacturing a coil for a rotating electric machine that has excellent mechanical, electrical, and thermal properties.

[Structure of the invention]

(Means for solving problems) In order to achieve the above object, in the present invention.

The vicinity of the damaged part of the wire coating insulation at the dislocation part is covered with a prepreg insulating base material, and the upper and lower surfaces of the conductor, which are necessary to eliminate voids, are made semiconductive, and the sealed microvoids are included in the conductor. , which is characterized by eliminating corona generation from voids within the conductor.

In the description of the present invention, the terms "prepreg" and "semi-curable" have the same meaning, but they will be used differently to clearly distinguish between the members.

Further, to explain the means in detail with reference to FIGS. 1 and 2, the commonly used wire (G) is made of a copper wire, an inorganic base material such as glass fiber (not shown), and a thermosetting resin. It is mold-treated and combined into a Leber transposed shape as shown in Figure 2. By integrating the wire groups combined in this way,
Furthermore, ground insulation will be provided. The material combination structure at this time is shown in the sectional view of FIG. In other words, between the rows of the left and right wire groups, a prepreg fiber insulation material ■ made of fiber insulation treated with a thermosetting resin is inserted, and between the dislocation portion wire (1a) and the other cable wire (G). In order to prevent interlayer short circuits, an inorganic insulating material (2) made of a combination of an inorganic insulating material such as mica material and a thin insulating material and treated with a thermosetting resin is inserted. In the recesses caused by dislocations, embed an insulating base material (2/4 to 3/4 of the total thickness of the prepreg insulating base material (4a) made of fibrous insulating material treated with thermosetting resin), and then Partial wire (1a)
1/4 to 1/4 of the total thickness of the insulating base material (A) over the top of the
2/4 is a semi-hardened insulating base material (2/4) is a fibrous insulating base material mixed with a semi-conductive powder inorganic material and a thermosetting resin and heated.
Overlap 4b). This is molded under heat and pressure in a predetermined mold to obtain a coil conductor. The subsequent ground insulation is the same as before.

(Function) Transposed element wire of conductor for coil obtained in this way (1a)
The part where interlayer short circuit between the wire and the other wire (■) is likely to occur, that is, the prepreg insulating base material (4a) part, is covered with a prepreg insulating base material (4a) that prevents the semiconductive powder resin from flowing in during hot press molding. 4a) The outer part of the wire covered with layer 4b, that is, the part of the semi-hardened insulating base material (4b), has the same potential as the conductor wire even when high voltage is applied in actual use, and the part due to the included microvoid In order to eliminate the occurrence of discharge, the 1 volume resistivity can be adjusted to 102 to 106 Ωd. In addition, the amount of semiconductive resin flowing out of the semi-curing insulating base material (4b) is the same as that of the semi-curing insulating base material (4a) and the semi-curing insulating base material (4b).
This is the extent to which the two are completely in close contact with each other. Thereafter, a dry mica tape is wound, vacuum impregnated with a thermosetting resin, and molded under heat and pressure to form a hardened ground insulation layer, or a prepreg mica tape containing a large amount of epoxy resin is used as a conductor. Roll it up and heat and pressurize it under reduced pressure to form a hardened ground insulating layer (2).

A feature of the present invention is the use of the prepreg insulating base material (4a) and the semi-curable insulating base material (4b) as described above. If the thickness of the semi-hardened insulating base material (4b) is 2/4 or more of the entire insulating base material (a), short circuits will occur between the wires, and if the thickness is 1/4 or less, the volume resistivity for actual use will not be obtained. There are drawbacks that cannot be avoided. That is, the volume resistivity of the semiconductive base material is 102
If it is less than Ωd, there is a disadvantage that the eddy current product increases, and if the volume resistivity is more than 10"02, partial discharge generated from voids included in the prepreg insulating base material (4a) cannot be completely suppressed. cannot be eliminated, and ultimately deteriorates insulation performance.

The volume resistivity when manufacturing semiconductive base material is 102 to 10'Ωd.
The reason for this is that when a hardened insulating layer is formed on a conductor, the volume resistivity of the surface of the conductor wire in actual use is 103 to 10''Ω.
This is to make it d.

Mica powder is used as a semiconductive resin flow prevention material during heating and pressure molding in a predetermined mold. If the mica powder is less than 30 parts by weight relative to the weight ratio of the semi-cured insulating base material (4b), it will not be possible to prevent the semiconductive resin from flowing out, and if it is more than 45 parts by weight, the conductor will not have the specified dimensions and will be integrated. conductor cannot be obtained.

(Example) Example 1 The first example of the present invention will be described below with reference to FIGS. 1 and 2.
This will be explained with reference to the figures. A flat copper wire coated with double glass fiber and baked with a polyester face was then transposed into two rows of 30 rows (Figures 1 and 2) by Lebel rearrangement.
(In the figure, it is shown in 10 stages in a simplified manner). Between the rows of these wires, as shown in Fig. 1, 40 parts by weight of Epikote 828 and 56 parts by weight of Epicoat 1001 (both trade names of Shell Kagaku Co., Ltd.) were used as hardening agents.
Prepreg fiber insulation material (2) made of a glass cloth prepreg sheet with a thickness of 0.20 NW containing 40 parts by weight of a resin consisting of 4 parts by weight of B F, 400 (product name of Hashimoto Kasei Co., Ltd.)
Insert.

Below the Siebel dislocation, a glass cloth was attached to the peeled mica, and s8 was made of a 0.25 mm thick mica sheet containing 10 parts by weight of the resin. Insert quality insulation material ■. Next, the thickness of the insulating base material (a) on the Siebel dislocation is 578
(2.5m thick in this case) prepreg insulation base material (4a)
The manufacturing method is to apply 20% of Epicoat 828 to a laminated mica foil.
17 parts by weight of Epikote 1001 (both trade names) as a curing agent BF, MEA (BF, 400
A resin compound consisting of 3 parts by weight of Hashimoto Kasei Co., Ltd. (trade name)
A prepreg insulating base material (4a) is prepared by including 5 parts by weight.

Next, the manufacturing method of the semi-cured insulating base material (4b) having a thickness of 3/8 (1.5 m in this case) is to add D E N438 (Dow Chemical Co., Ltd.) to a glass nonwoven fabric with a thickness of 1.0Iff11. Mix 27% of AER661 (trade name), 12% of AER661 (trade name of Asahi Kasei Corporation), 2% of BF and MEA, then 1.5% of Denka Black (trade name of Denki Kagaku Kogyo) and 37.5% of mica powder. This semi-cured insulating base material (4b) is made into a prepreg insulating base material (4a) from above the bare dislocation part (1a) by containing 67% of the mixture consisting of %. Layer it all over the top.

After wrapping Parflon (trade name of Nippon Palcar Co., Ltd.) as a release material on top of it, it was heated at 150°C for 60 minutes at 15kg/aJ.
After winding the assembled mica dry tape a predetermined number of times, it is inserted into an impregnating tank and the pressure is reduced to lm.
After being impregnated with an acid anhydride epoxy resin at mHg, the coil was taken out from the tank and heated and molded at 90° C. for 3 hours and 180° C. for 15 hours to obtain a coil for a rotating electric machine with ground insulation.

Next, the effect will be explained.

The side surface of the formed conductor surface before ground insulation
No flow of semi-cured resin was observed on the (lb) side. Further, a conductor having a volume resistivity of 5×10′Ωd on the dislocation portion was obtained.

The rest is as explained in the section of the operation of the structure of the invention.

Example 2 A prepreg mica tape containing 45 parts by weight of an epoxy resin containing an acid anhydride was wrapped around the conductor produced in Example 1 on mica foil, and was heated for 15 minutes while reducing the pressure in a vacuum pressurized tank.
The coil was heat-molded at 0° C. for 25 hours to obtain a coil for a rotating electric machine.

Even in this case, the same effects as in the first embodiment can be obtained.

Comparative Example An insulating base material having a thickness of 4.5 nn as compared to the prepreg insulating base material (4a) used in Example 1 for a conductor having the same wire arrangement as in Example 1 is embedded in the concave portion of the Lebel dislocation.

That is, this conductor is not provided with a semi-hardened insulating base material (4b).

After winding Parflon tape on top of the tape, it is heated and pressurized at 15 kg/J at 150° C. for 60 minutes to be molded. Next, a conventional coil for a rotating electric machine was obtained for comparison using the same ground insulation treatment as in Example 2.

Typical characteristics of these coils for rotating electric machines are shown in Table 1.

Table 1: Variations in Δtanδ are 18 in Examples 1 and 2.
The comparative example shows the characteristics of 0 rotating electrical machine coils.The comparative example is conventional performance data.The characteristics of 144 rotating electrical machine coils are shown.Δtanδ is the value of tan δ measured between two voltages, and is 15. OKV -2, indicates OKV. As a result, Example 1 and Example 2 have a lower Δtan than the conventional comparative example.
The variation in δ and Δtanδ has been significantly reduced,
This shows that the insulated coil has significant mechanical, electrical and thermal advantages.

〔Effect of the invention〕

As is clear from the Examples and Comparative Examples detailed above, the rotating electrical machine coil obtained by the present invention eliminates the occurrence of partial discharge from the conductor, so the insulation performance of the coil is improved, and the coils of the rotating electrical machine are There is almost no variation in the insulation properties of the coil, and therefore, the life of the coil for rotating electric machines, which has excellent mechanical, W1 gas, and thermal properties, can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view taken along line A-A in FIG. 2 of a coil for a rotating electric machine manufactured by an embodiment of the method of the present invention;
FIG. 2 is a perspective view showing an uninsulated Lebel transposition conductor common to the conventional method and an embodiment of the present invention. 1... Element wire 1a... Dislocation part element wire 1b.
... Side part wire making 2 ... Prepreg fiber insulation material 3
...N-free insulating material 4...Insulating base material 4a...
Prepreg insulation base material 4b... Semi-curable insulation base material 5.
...Ground insulating layer Figure 1'sX 2 (3 Agent: Patent attorney Norio Ogo

Claims (1)

[Claims] In a method for manufacturing a coil for a rotating electrical machine, which has a plurality of strands, has an insulator disposed in the recess and the upper surface of a conductor having Lebel transposition, so that the cross section of the conductor is rectangular, and a ground insulating layer is provided on the outer periphery of the conductor. A prepreg fiber insulation material made by semi-curing a fibrous insulation material with a thermosetting resin is inserted between the rows of strands, and a thermosetting resin is inserted between the transposed strands and the other strands on which they overlap. The treated inorganic insulation material is inserted, and a prepreg insulating base material made of fibrous insulation treated with a thermosetting resin is embedded in the recess next to the wire created by the dislocation, and the upper part of the wire at the dislocation site and the prepreg are inserted. 3 for fibrous insulation over the top of the insulation substrate
Semi-curing material using 0 to 45 parts by weight of mica powder as a resin flow prevention material, mixed with semi-conductive powder and thermosetting resin and heated to have a volume resistivity of 10^2 to 10^6 Ωcm^2. 2/4 to 2/4 to the thickness of the insulating base material, which is the sum of the prepreg insulating base material and the semi-cured insulating base material when the insulating base materials are stacked.
3/4 is the thickness of the prepreg insulation base material, 1/4 to 2/
4 is the thickness of a semi-hardened insulating base material, which is heated and press-molded in a predetermined mold to produce a coil conductor, and this conductor is provided with ground insulation. Production method.