JPS626409B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a coil for a rotating electrical machine,
In particular, the present invention relates to a method for manufacturing a vacuum pressure impregnated coil that has been subjected to corona prevention treatment.

Conventionally, as shown in Fig. 1, as a corona prevention method for the iron core end of a rotating electric machine coil, low resistance ( Surface resistivity 10 ² ~ 10 ³ Ω)
Form a low-resistance layer 4 by applying a paint or winding tape, and then winding asbestos tape, or paint containing graphite or carbon black with a surface resistivity of about 10 ⁶ to ^{10 8} Ω, or A high-resistance layer 5 is formed by applying or winding a tape or the like.
A method was used to form a

However, the supply of asbestos tape has become increasingly tight due to problems such as pollution, and restrictions have been placed on its use. In addition, in the case of the vacuum pressure impregnation method, there is a large variation in voltage-tanδ characteristics due to fluctuations in resistance value due to resin impregnation. Furthermore, as shown in Figure 2 (insulation thickness 4 using asbestos tape)
mm), the value of the dielectric loss tangent (tan δ ₀ ) tends to become large at a voltage below the onset of corona.
There were disadvantages in that there were cases where foreign standards (for example, VDE0530) could not be met. In addition, when applying or winding graphite or carbon-containing paint or tape, the resistance value increases because the resin infiltrates between the graphite or carbon particles due to vacuum pressure impregnation, and the high-resistance layer at the end of the core becomes As if it had disappeared,
At the boundary A between the low-resistance layer and the high-resistance layer in Figure 1, the slope of the voltage becomes large, causing corona discharge, and as shown in Figure 2 (in the case of insulation thickness 4 mm using carbon black or graphite-containing paint or tape). As shown, tan δ increases rapidly beyond a certain voltage, and the corona suppressing effect disappears.

The present invention has been made to solve these problems.

An embodiment of the present invention will be described below based on the drawings.

60±5 parts by weight of silicon carbide powder (SiC) with a particle size of #100 to #1500 (JIS R6001), preferably #600 to #800, and 3 to 3 parts of boron trifluoride monoethylamine complex to DEN438 (manufactured by Dow Chemical Company). 4phr
Dissolve 35±5 parts by weight of the mixture in a small amount of a solvent such as methyl ethyl ketone or toluene and apply the paint to glass cloth or polyester fiber so that the total paint content is about 80±10% and dry to form a prepreg. Obtain high resistance tape. Thereafter, as shown in an embodiment of the present invention shown in FIG. 3, a low resistance tape 4 was wound around the surface of the insulating layer 2 formed on the conductor 1, inside the iron core 3, and several tens of mm outside the outlet. Subsequently, this prepreg-like high-resistance tape 6 is wound. Further, from above, a tape 7 impregnated with a plastic film such as polyimide, polyimide amide, polyoxodiazole, polyethylene terephthalate, polytetrafluoroethylene, or rubber such as silicone, which does not dissolve in resin, is covered on the surface of the prepreg-like high-resistance tape. The prepreg-like high-resistance tape 6 is wound so that it is not directly exposed to the surface.

In this way, we use tape that does not dissolve in resin,
By preventing the prepreg-like high-resistance tape 6 from being exposed on the surface, the tape that does not dissolve in the resin suppresses the prepreg-like tape, so that the impregnated resin invades the prepreg-like high-resistance tape.
It is possible to prevent the paint in the high-resistance tape from swelling, and also to prevent the silicon carbide powder-containing epoxy paint from flowing out during impregnation and curing, resulting in a loss of functionality. In addition, there is good adhesion between the insulating surface of the coil and the prepreg-like high-resistance tape, and between the low-resistance layer 4 and the prepreg-like high-resistance tape, and no voids are formed there, so that it is possible to suppress the occurrence of partial discharge in these parts. Note that the tape that does not dissolve in the resin may be wound using a single-sided adhesive tape so that the adhesive side faces the prepreg-like high-resistance tape 6, depending on the convenience of the work. After this, an insulated coil is obtained by vacuum pressure impregnation with a thermosetting resin such as epoxy, polyester, polyimide, etc. and heat curing by a known method. In the coil obtained in this way, the overlapped layers of the high-resistance tape 6 are prepreg-like, so they stick together well, and because they are prepreg-like, they stick well to the insulating surface and conductive layer, so that some parts The occurrence of electrical discharge can be reliably suppressed. Furthermore, since the prepreg-like high-resistance tape becomes a non-linear resistor after curing due to the use of silicon carbide powder, as shown in FIG. 2 (in the case of the present invention), tan δ ₀ is As with no winding, it can be kept lower than the existing standard value, and by lowering the resistance on the high voltage side, the potential distribution at the end of the iron core is equalized,
It is possible to suppress the generation of corona, and to obtain an insulated coil with less variation in V-tan δ characteristics than the above-mentioned asbestos.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a coil of a conventional rotating electrical machine, FIG. 2 is a voltage-tan δ characteristic diagram of coils produced by the conventional and manufacturing methods of the present invention, and FIG. 3 is a diagram of a coil of a rotating electrical machine according to an embodiment of the present invention. FIG. 3 is a cross-sectional view at the end of the core. 1...Conductor, 2...Insulating layer, 3...Iron core, 4...Low resistance layer, 5...High resistance layer, 6...Prepreg high resistance tape, 7...Tape that does not dissolve in impregnated resin,...Conventional case of using asbestos tape , ... in the conventional case using graphite or carbon-containing tape or paint, ... in the case of the manufacturing method of the present invention.

Claims (1)

[Claims] 1. In a method for manufacturing a coil to be housed in the core of a rotating electrical machine, a prepreg-like tape containing silicon carbide powder is wound around the insulating surface of the core end of the coil,
A tape that does not dissolve in the impregnating resin is wound thereon to cover the surface of the prepreg tape to block the infiltration of the impregnating resin into the prepreg-like tape, and the thermosetting resin is impregnated with vacuum pressure and cured. A method of manufacturing a coil for a rotating electric machine.