JPS6118411B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a coil for a rotating electric machine, such as a turbine generator, a water turbine generator, etc., which has a particularly high working voltage. In insulated coils for high-voltage rotating electric machines, efforts are being made to obtain an insulator with as few voids as possible in order to prevent corona discharge inside the insulator.
In general, insulation treatment is performed by the following method on a coil conductor that is formed by heating and forming a coil conductor by filling the empty part of a group of wires made by transposing and combining insulated wires with varnish or compound. . This is the so-called vacuum pressure impregnation method, in which a predetermined number of turns of laminated mica tape or peelable mica tape are impregnated with thermosetting resin under vacuum pressure, and then heat molded to obtain an insulated coil. This is the so-called prepreg method, in which a pre-preg tape made of laminated mica or peelable mica containing a large amount of thermosetting resin is wound around a predetermined number of times, and then an insulated coil is heat-formed. Two methods have been adopted. In the above methods () and (), the properties of the obtained insulating layer are almost the same, but ()
Compared to the method (), the method () requires vacuum and pressure impregnation equipment, and the handling of varnishes during work has problems in terms of workability. It has become more widely used. As is well known, coil conductors for high-voltage rotating electric machines are made by combining many small conductor strands in order to eliminate eddy currents, but especially in high-voltage and large-capacity equipment, the coil conductor for high-voltage rotating electrical machines is made by combining many small conductor wires to eliminate eddy currents. In order to eliminate internal circulating currents, a method called Lebel transposition is generally used. Therefore, large irregularities occur on the surface of the coil conductor, especially at the dislocation portion. In addition, since the strands alone are easily deformed and cause problems when winding the mica tape, varnishes or compounds are usually used to bond the strands together and fill in the uneven parts, especially the depressions, to form the coil. Work is underway to smooth the surface of the conductor. However, since such conventional methods involve handling varnish and compounds, the work is not only complicated, but also poses health and safety problems for workers, such as odor and rashes. In addition, the coil conductor manufactured in this way is
The internal voids cannot be completely filled, and as a result, even if the manufacturing process of the mica tape insulation layer applied as the ground insulation layer is perfect, if there are voids in the conductor part, the insulated coil will not be used properly. In this case, corona was generated, which ultimately led to a decrease in insulation performance, which was undesirable. The present invention provides an insulated coil that can eliminate all of the above-mentioned conventional drawbacks, improves workability, simplifies manufacturing, and improves mechanical, electrical, and thermal properties of the final insulated coil. The present invention provides an extremely innovative method for manufacturing a coil for a rotating electric machine, which has sufficiently excellent properties. In other words, this invention eliminates the handling of varnishes in each manufacturing process of coil conductors and ground insulation, improving work efficiency, and furthermore, eliminates the need for handling varnishes in each manufacturing process of coil conductors and ground insulation.
The coil conductor, which is difficult to eliminate, is made semiconductive, and all microvoids sealed in the coil conductor are made to have the same potential as the wire group, thereby completely eliminating corona generation from the included voids. That is. However, since the coil for a rotating electric machine obtained according to the present invention contains almost no voids in the insulating layer, it is possible to manufacture an insulated coil with extremely excellent corona resistance. Next, a case in which an embodiment of the present invention is applied to a coil for a rotating electric machine will be described in more detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a coil conductor made by combining insulated wires by Lebel transposition, and FIGS. 2 and 3 are cross-sectional views of an insulated coil for a rotating electric machine obtained according to an embodiment of the present invention. . The commonly used insulated wire 1 is made by insulating a copper wire with an inorganic base material such as glass fiber or mica powder and a thermosetting resin.
As shown in FIG. 1, they are combined into a Leber transposed shape. The wire groups thus combined are integrated and further insulated to the ground, and the material combination structure at this time is shown in FIGS. 2 and 3. That is, a prepreg insulating material 2 made of a porous insulating material treated with a thermosetting resin is inserted between the rows of one group of left and right strands of strands, and a prepreg insulating material 2 made of a porous insulating material treated with a thermosetting resin is inserted between the dislocation-free strand 1a and the other insulating strands 1. In order to avoid interlayer short circuits, a prepreg insulating material 3 made of a porous insulating material treated with a thermosetting resin is inserted. A semiconductive prepreg material 4 cut to the width of two rows of strands made by treating a porous insulating material with a conductive or semiconductive powder and a thermosetting resin is placed on the dislocation portion. Furthermore, if necessary, a sheet or tape of a semiconductive prepreg material 5 made of a semiconductive base material treated with a thermosetting resin is applied around the entire circumference of the coil conductor, and this is heated and heated in a predetermined mold. A coil conductor is obtained by pressure forming. The surface of the coil conductor thus obtained, that is, the semiconductive prepreg material 4 in FIG.
Parts 4 and 5 of the same configuration in the figure have a volume resistivity of 10 ⁴ to 10 ⁹ Ωcm in order to maintain the same potential as the insulated wire even when high voltage is applied in actual use, and to eliminate corona generation due to the included minute voids. It has been finished. Thereafter, mica prepreg tapes 6 made of assembled mica containing a large amount of thermosetting resin and peelable mica are wound around the coil conductor, and molded under heat and pressure to form a hardened ground insulating layer. The feature of this invention is that the semiconductive prepreg materials 4 and 5 are used as described above, but as shown in FIG. In addition to further demonstrating the effects of this invention, the resin in the semiconductive prepreg material has more fluidity than the microwave in the mica prepreg tape when heated, so when heating the mica prepreg tape,
Since it is on the coil conductor whose temperature rises slowest, it also has the role of making the flow of the resin easier and improving the adhesive force with the coil conductor. The prepreg insulating material 2 may be one or two types of commonly known porous insulating materials such as glass cloth, polyester cloth, polyester nonwoven fabric, peelable mica, laminated mica, various films, aspest paper, aromatic polyamide paper, etc. A combination of these is coated with a thermosetting resin and dried to a semi-cured state. The amount of resin attached depends on the type of substrate used, but
30 to 85% (weight %, the same applies hereinafter) is suitable. In addition, thermosetting resins include commonly known unsaturated polyesters, epoxies, phenols, alkyds, silicones, esterimides, polyamides,
Although most synthetic resins such as polyimide can be put to practical use, epoxy resins are particularly suitable as they have a high adhesive strength as a cured resin and have a long shelf life in the prepreg state. The porous insulating material 3 may be made of glass cloth, aromatic polyamide paper, peelable mica, etc., although most of the above-mentioned prepreg insulating materials can be put to practical use as they are. , laminated mica prepregs are particularly preferred. The semiconductive prepreg material 4 used on the dislocation site is a material consisting of a relatively porous base material such as glass fiber felt, polyester nonwoven felt, or laminated mica, the resin, and a conductive or semiconductive material such as carbon powder or silicon carbide powder. A prepreg material made of a conductive substance is suitable, and a material having a volume resistivity of 10 ⁶ to ^{10 9} Ωcm after heat molding is preferably selected. The composition ratio of these three materials is
For every 100 parts, 60 to 500 parts of resin and 5 to 100 parts of conductive or semiconductive material are preferred. In addition to the above-mentioned semiconductive prepreg materials, prepreg materials made of a conductive or semiconductive base material and a resin are also suitably used. A representative example thereof is a prepreg material using carbon fiber felt as a base material. The volume resistivity of the dislocation area of the coil conductor obtained by heat forming using the prepreg material explained above is
It is finished with a resistance of 10 ⁴ to 10 ⁹ Ωcm. Here, when the volume resistivity is 10 ⁴ Ω or less, there is a drawback that eddy current loss increases, and if the insulation coating between the wires is damaged, there is a short circuit between the wires. Further, if the volume resistivity is 10 ⁹ Ωcm or more, the object of the present invention cannot be achieved, and both are not preferable. Note that the semiconductive prepreg material 6 in the configuration shown in FIG. Materials are preferred, particularly those that shrink when heated. The structure of the prepreg material and the effect after heat forming are as described above, but in Fig. 3, the effect of the present invention can be demonstrated around the entire circumference of the coil, so a more perfect insulated coil can be manufactured. be. Furthermore, mica prepreg tapes containing a thermosetting resin and forming the ground insulating layer of the present invention will be explained. Laminated mica tape is a laminated mica sheet produced by a firing method or a water jet method, with a backing material such as glass cloth, polyester nonwoven fabric, paper, various polyester films, etc., and a thermosetting material such as those exemplified above. 15-80% resin
It is finished in a semi-cured state to facilitate taping. Peelable mica tape is made of No. 4 to No. 6 phlogopite or muscovite using the same backing material and resin system as those used for the laminated mica tape, and is finished in a semi-cured state. These mica prepreg tapes are wound a predetermined number of times on a coil conductor, and then heated and pressed to form an insulated coil. The molding conditions in this case depend on the resin system used, but are usually 3~
Under a pressure of 20Kg/ ^cm2 , at a temperature of 100-170℃, from 1 to
Molded for 15 hours. As described above, the insulated coil for a rotating electric machine obtained by the method of the present invention is easy to manufacture and has excellent workability since all the materials used are prepreg materials.
In addition, the obtained insulated coil has excellent electrical properties because it completely eliminates the generation of corona due to voids in the coil conductor, which has been a problem in the past. In addition, since the resin system used for the prepreg material can be arbitrarily selected, it is possible to manufacture an insulated coil having excellent properties in all aspects of mechanical and thermal properties. EXAMPLES The present invention will be specifically described below with reference to Examples. Example 1 As shown in Figure 1, a 2.2 mm x 5.7 mm insulated wire made by coating a rectangular copper wire with double glass fiber and baking with alkyd varnish [product of Dainichi Nippon Denki Co., Ltd.] 1 was rearranged and combined into two rows and 21 stages. Between the rows of this 1 group of wires, as shown in Figure 2, 100 copies of Epicoat 1001 (trade name manufactured by Ciel Chemical Co., Ltd.),
A prepreg insulation material 2 made of a 0.50 mm thick glass cloth prepreg sheet containing 60% of a resin consisting of 4 parts of BF ₃ monoethylamine was inserted. A 0.25 mm thick Nomex prepreg sheet containing 35% of the above-mentioned resin was inserted into Nomex #410 (trade name, manufactured by DuPont) as the prepreg insulating material 3 under the Lebel dislocation. On the Lebel dislocation, 80 parts of Epikote 1001 (mentioned above), 20 parts of Epicoat 834 (product name of Ciel Chemical Co., Ltd.), 4 parts of BF ₃ monoethylamine, and carbon powder were added to polyester nonwoven felt (product name: HP-35, product of Nippon Vilene Co., Ltd.). A semiconductive prepreg material 4 containing 75% of a compound consisting of 9 parts of acetylene plaque (particle size 0.5 to 5μ) was layered and molded at 160°C for 30 minutes at a pressure of 10Kg/cm ² .
A coil conductor having a volume resistivity of 2×10 ⁷ Ωcm on the dislocation site was obtained. Next, as the laminated mica tape 6, Samikatherm 366-28-02 (trade name, manufactured by Isola, Switzerland, thickness 0.18 mm, width 30 mm) was wound a predetermined number of times in a half-overlap manner, and then the tape was wound at 110°C x 1Hr + 150°C x 13Hr.
An insulated coil with an insulation thickness of 3.0 mm was obtained by heat molding. Example 2 Using the same coil conductor as that produced in Example 1, a Tetron glass interwoven fabric [manufactured by Arisawa Seisakusho Co., Ltd., thickness 0.1 mm, shrinkage rate 10% at 110°C] was coated on the coil conductor. 1. A tape with a width of 30 mm containing 54% of the compound used in semiconductive prepreg sheet 4 was wound once as semiconductive prepreg material 5 by butt winding. Thereafter, the mica tape assembly was wound and heated in the same manner as in Example 1 to obtain an insulated coil with an insulation thickness of 3.0 mm. Example 3 Using the same coil conductor as that produced in Example 1, Samikatherm 366-28- was applied on this coil conductor.
02 and peelable mica tape having the following configuration were alternately wound in a half-overlap manner. Thereafter, an insulated coil with an insulation thickness of 3.0 mm was obtained under the same molding conditions as in Example 1. Peel off mica...One side of the 4-layer backing material made of No. 5 phlogopite...Polyethylene terephthalate film (thickness 0.025mm) One side of the backing material...Glass cloth (thickness 0.03mm) Resin...Nopolac epoxy resin and Comparative example 1 containing 35% hardening agent Example 1 was applied to a coil having the same wire shape as Example 1.
The prepreg insulating materials 2 and 3 used in 2 were inserted, a polyester nonwoven felt was layered on the Leber dislocation, and an unsaturated polyester varnish containing styrene and an organic peroxide was applied to the entire coil. Thereafter, it was molded at 130°C for 1 hour to obtain a coil conductor. Thereafter, the assembled mica tape was wound and heated in the same manner as in Example 1 to obtain an insulated coil with an insulation thickness of 3.0 mm. Typical characteristics of these insulated coils are shown in Table 1. However, Δtanδ is the value when the dielectric loss tangent is measured between two voltages, and is 5KV/mm−0.5KV/mm.
It shows the value of Further, Δtanδ after heat deterioration indicates the value when a voltage of 10 KV was applied for 10 days at 90°C.

[Table] As is clear from the Examples and Comparative Examples detailed above, the insulated coil for rotating electric machines obtained by the present invention is easy to manufacture and has excellent workability. By eliminating the generation of corona from the conductor, the performance of the insulated coil is greatly improved, which in turn significantly extends the lifespan of rotating electrical machines.This is an extremely groundbreaking product and has great industrial value. In addition, in this invention, it is also possible to apply a protective tape or a corona shield layer to the surface of a coil for a rotating electric machine having the excellent characteristics as described above, and it is possible to apply a protective tape or a corona shield layer to the surface of the coil for a rotating electric machine, which has the excellent characteristics as described above. It can be used selectively.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a coil conductor subjected to Lebel transposition, and FIGS. 2 and 3 show an example of an insulated coil for a rotating electric machine obtained by the manufacturing method of the present invention, and both are It is a sectional view taken along the line -' in the figure. 1...Insulated strand, 1a...Dislocation-free strand, 2,
3... prepreg insulating material, 4, 5... semiconductive prepreg material, 6... mica prepreg tapes.

Claims (1)

[Claims] 1. A prepreg insulating material made of a porous insulating material treated with a thermosetting resin is inserted into the empty space of a group of strands formed by transposing and combining insulating strands, especially between the strands and between the strand rows, On the dislocation part, there is a semiconductive prepreg material in which a porous insulating material is treated with conductive or semiconductive powder and a thermosetting resin, or a semiconductive prepreg material in which a semiconductive base material is treated with a thermosetting resin. A process of stacking the coil conductors and forming them under heat and pressure in a predetermined mold to obtain a coil conductor.A process of wrapping a mica prepreg tape containing a large amount of thermosetting resin in advance on the coil conductor. A method for manufacturing a coil for a rotating electrical machine, comprising the step of forming a hardened insulating layer by molding.