JPS6176048A - Insulating method for stator coil - Google Patents

Abstract

PURPOSE:To minimize a working space without necessitating an expensive heating and pressure-molding making machine, by a method wherein an insulated coil conductor contained in a mold is vacuum pressure-impregnated with resin and the resin is hardened in a drying furnace. CONSTITUTION:A coil conductor 1 is provided with a main insulation of mica tape and with a semiconductor layer 7 on which Teflon film tape 2 for insulation is wound up leaving a coil end unwound. The sides of the insulated coil 1 are contained in a mold 4 consisting of core bars 8 and side plates 9 and are tightened. And in a state that the coil 1 is contained in the mold 4, the coil 1 is vacuum pressure-impregnated with resin, and the resin is hardened in a drying furnace as specified, and finally, the mold 4 is removed and the Teflon film tape 2 for the outermost layer is also removed. By this process, pressure need not be applied at the time of heating at a high temperature, and so, stress applied on an insulating layer 6 can be minimized and an expensive heating and pressure-molding making machine also is not needed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of insulating a stator coil, and more particularly to a method of insulating a coil of a large high-voltage leg.

Conventional technology In general, large-sized high-voltage stator fills are produced by insulating the coil conductor with Dry Chee 1, impregnating it with resin under vacuum pressure, and shaping it under heat and pressure; or by insulating the coil conductor with Semi-Cure Chee 1. There is a heating and pressing bottom type process in the insulation and heating and pressing process.

However, the heating and pressing bottom type described above has air bubbles (
The key is to mold it to the specified dimensions without creating voids or release layers. To this end, the gelling properties of the resin,
It is necessary to understand the temperature increase rate, temperature distribution of the object to be treated, etc., and pay close attention to the timing of pressurization. In other words, if the timing of pressurization is too early, the resin will flow out and bubbles will form in the insulating layer, while if the timing is too late, gelation will progress and the desired dimensions may not be achieved. If pressure is applied, cracks or peeling will occur in the insulating layer.

Problems to be Solved by the Invention However, if an air layer is formed in the insulating layer due to bubbles or cracks, when high pressure is applied, partial discharge occurs in the air layer and the insulating layer is damaged. It may deteriorate and lead to absolute destruction over a long period of time. For this reason, the presence and size of bubble f-cracks is checked by partial discharge tests, but there are many variations because it is difficult to control the heating and pressurizing conditions, and it is not possible to completely prevent the occurrence of bubbles and cracks. However, the yield of the product is low.Also, due to the heating and pressurizing conditions, since the dimensions are compressed by applying pressure, stress remains in the coil insulating layer to try to return to its original state, and as a result, the temperature during operation increases. As the temperature rises, the temperature of the insulating layer rises, and when the resin layer is slightly pressed, the insulating layer swells, causing air bubbles. This may cause peeling.

Elaborate means to solve the problem and non-invention to cover the coil? The key point is to prevent the formation of gap layers such as bubbles and cracks in the 5R layer, and to suppress the expansion of the insulating layer when heated at high temperatures. For this reason, the uninvented method is characterized by consisting of the following steps (1) to (2).■ The coil conductor is insulated with mica tape as the main material, a semiconductive layer is further provided, and a Teflon film film is applied on top of that. ” s Wrap and insulate the coil, leaving part a of the coil end.

■ Place the side of the insulated coil into a bottom-shaped mold consisting of a core bar and side plate of the specified dimensions and tighten to the specified dimensions. The core metal and side plates are made of aluminum or iron.

■Place it in a bottom mold 11. Perform pressure impregnation treatment with true nitrogen for the resin.

(11) Placed in a mold and subjected to prescribed hardening treatment in a drying oven. At that time, the coil end is cured in such a position that the head is above the coil side.

-14 Remove.

According to the above method, the coil conductor is coated with an insulating layer mainly composed of mica 1, further provided with a semiconductive layer, and then wrapped with Teflon film 1' fr: from the outside of the coil, so it is necessary to apply pressure when heating at high temperatures. Since there is no stress on the insulating layer, there is less swelling of the insulating layer due to heat cycles, which reduces the formation of gap layers such as bubbles peeling off and cracks on the insulating layer. .

2. The purpose of wrapping the tear belt 1 in step 2 above is to improve release from the mold and to prevent the resin from flowing out. 17? :, Teflon Chi 1
The reason why the head is not taped is to ensure a resin inflow path. The reason why the coil end is cured with the head of the coil end facing upward in step (2) is to prevent the resin from flowing out during curing.

EXAMPLE An example of the method of the present invention will be described with reference to FIGS. 1(8) to 5 2).

In the figure, l is the coil conductor knee for the high-voltage solid foot, and the tear film tape 1 is wound around the outside of the coil conductor
I'll go. Both ends of the coil conductor l are bent upwards,
In addition, one Teflon film was left unwound to form the coil end head 3, which is a bottom type mold, and the compression relationship between this and the coil conductor l is shown in FIG. In other words, the coil conductor / is first formed by bundling a plurality of linear conductors into a rectangular shape on the jt-M plane, and the outside of the coil conductor is ! An insulating layer 6 is formed on the main body of the Ikachi 1t, and a semiconducting layer 7 is formed on the outside of the insulating layer 6. Further, on the outside of the insulating layer 6, the above-mentioned two ends are left as coil end heads J, J, and other parts are formed. Wrap tearless film tape.

The above coil conductor/i is formed in the first step.

The straight line M1 of the above coil conductor l is formed by forming the amount ≠
W≠ for 1 figure to be placed inside is the core metal r, r and side plate of predetermined dimensions as shown in Fig. 2? , 9, with core metals r and t1 applied to both ends of the rectangular #-plane coil conductor in the longitudinal direction,
Apply side plates and girders to both measuring parts, and attach this core metal 1. and the side plates 2, 2 are constructed using aluminum, iron, FRP, or the like. And core metal T.

? Using the side plate 5' and Pft, tighten the above 45mm coil conductor/1ji to the predetermined dimension 1.

That's all a! It is a two-step process.

Subsequently, the coil conductor is impregnated with a resin under vacuum pressure while being placed in the above-mentioned mold.

The above is the third step.

Next, the coil conductor 1' fitted into the mold for the kg type is subjected to a predetermined hardening treatment in a drying oven. At this time, the coil end head 3.3 is cured in a posture such that it is above both ends of the coil straight section. This is because the insulation N is used in the previous process during curing.
This is to prevent the resin impregnated into B from flowing out.

The above is the fourth step.

Finally, after the resin has cured, the molded tear film tape is removed.

The above is the fifth step.

Therefore, Figures 3, 4, and 5 show the relationship of insulation properties when using the above method. In other words, Figure 3 shows the relationship between φ for molding with and without tearless film tape. This shows the characteristics when the S edge layer B is impregnated with resin under vacuum pressure. That is, it can be seen that the insulation properties are better when the Teflon fill tape λ is included. Figure 4 shows the insulation characteristics t7r, μ when the coil end head 3t is in the upward position and in the downward position during the resin curing in the 4th step.
As can be seen from the curve in the same figure, when the coil end head 3 is in the upward position, the resin does not flow out during curing and the coil conductor l
It can be seen that the insulation properties of .

Furthermore, Figure 5 shows the case of vacuum pressure impregnation treatment on the resin in the third step, and the case of conventional heating and pressure impregnation treatment under the heat cycle conditions from normal room temperature to about 160°C1. When using the pressure method? Dimensional change, shrinkage insulating layer 6
Change in swelling? It shows. As can be seen from the figure, the dimensional change is smaller in the case of non-invention.

It has more power than the effect of invention, and according to non-invention, it has the following effects.

111 Since the insulated coil conductor is placed in a 11A type mold and impregnated with resin under vacuum pressure, and then hardened in a drying oven, there is no need for an expensive hot-press molding machine as in the past, and it takes up less space. Less is needed.

+21 With conventional heating and pressure molding methods, if you want to process a large number of coils at once, you have to install many heating and pressure molding machines, which is a waste of money, but according to the present invention, it is easy and It is possible to process a large amount of coils, and therefore the manufacturing period can be greatly shortened.

(31? The fluorocarbon film tape is taped except for the coil end head, and during curing, it is cured with the fill end head facing upward, so it does not impede resin impregnation, and during curing Since there is almost no resin O leakage, there are few air bubbles in the insulating layer, and a coil with good absolute R% properties can be produced.Furthermore, Teflon Chi 1 has good patternability, so it is easy to remove from the coil conductor in the mold. It is also easy to remove p.

141 Compared to the conventional heating and pressing method, since no pressure is applied when the bottom is formed, no excessive force is applied to the insulating layer, which reduces the variation in insulation properties seen in the conventional method and improves fPw.

(51 non-inventiveness is that the pressure modulus of the insulation dimension due to pressurization is not large as in the case of conventional heating and pressurizing methods,
Accordingly, the stress applied to the insulating layer is small (and the expansion of absolute RN due to the t-1 cycle is also small.

[Brief explanation of drawings]

The figures show an embodiment of the uninvented method, and Fig. 1 is a front view of the coil conductor being carefully placed in the mold, and Fig. 2 is the i1 figure A-'A.
Enlarged cross-sectional view along the line, the third factor is Teflon film chip 7
The insulation characteristics of the coil conductor with and without the insulating layer are impregnated with resin under vacuum pressure. Figure 4 shows the insulation characteristics of the coil conductor with and without the insulation layer. Figure 5 shows the absolute f&characteristic diagrams of the coil conductor when the head is in the upward and downward postures. l'l'l Kanji edition j dark blue ■ h Now person B? To Konsukeko 2
FIG. l...Coil conductor, λ...Thiamin film teeth J...Coil end head, φ...Mold for bottom shape, 6...
・Insulating layer.

Claims (1)

[Claims] In a method for insulating a stator coil, the coil conductor is insulated mainly with mica tape, further provided with a semiconductive layer,
The first step is to leave the coil end head on the outermost layer and tape it with a releasable tape such as Teflon film tape, and then the second step is to attach a molding die from the outside of the straight portion of the coil, and the coil conductor. The third step is to impregnate the insulating layer with resin under vacuum pressure while it is attached to the mold, and then the resin is hardened in a drying oven with the coil end head facing up while it is attached to the mold. A method for insulating a stator coil, comprising: a fourth step of removing the mold from the coil conductor and removing the outermost layer of releasable tape.