JPS6013445A - High voltage coil of rotary electric machine - Google Patents

Abstract

PURPOSE:To improve the withstand voltage characteristic and mechanical stress resistance characteristic by arranging an insulating layer formed of an unbaked lumped mica tape or sheet mixed with synthetic resin at the center of the thicknesswise direction of a coil insulator at which a mechanical stress caused by a thermal expansion or contraction is concentrated. CONSTITUTION:A high voltage coil 2 is composed of coil conductors 4 having a rectangular section formed of flat conductors respectively covered with a plurality of insulators, a baked lumped mica tape layer 5a wound in contact with the outside of the conductors 4, an unbaked lumped mica tape or sheet layer 6 mixed with polyester fiber or aromatic polyamide fiber wound in contact with the outside of the layer 5a, a baked lumped mica tape layer 5b wound in contact with the outside of the layer 6, and a low resistance conductive layer 7 formed on the outside of the layer 5b. The two coils 2 are inserted into a slot 1 in the unimpregnated state, impregnated with resin in full-impregnation insulating type, and then thermally cured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to Which the Invention Pertains] The present invention relates to an insulating structure for a high voltage coil impregnated with a resin and fixed in a core groove of a rotating electrical machine using a full impregnation insulation method.

[Prior art and its problems]

There is a total impregnation insulation method as a manufacturing method for high-voltage rotating machine coil insulation. In this method, a coil conductor with ground insulation is inserted into a slot in the core, and the entire core is transported to a resin impregnation tank where it is impregnated with epoxy M 11M, polyester resin, etc. in vacuum and pressure, and then heated and cured. It is something. In the case of high-voltage rotating machine coil insulation produced using this fully impregnated insulation method, an unimpregnated coil whose coil conductor is wrapped with insulating tape such as laminated mica tape to a specified thickness is inserted into a slot in the iron core of the rotating electric machine. Therefore, the insulating tape used should be as flexible as possible and can be wrapped closely around the conductor.
Looseness and sagging in the wound tape layer.

It is desirable that there is little bulge. This is because if there is any looseness, slack, bulges, etc. in the tape layer being wound, when it is inserted into the slot, the looseness, sag, bulges, etc. of the tape layer will be squeezed to one side of the coil with a rectangular cross section, and the resin When impregnated with M, there is a drawback that a M fat pool is formed in the insulating layer in this part, making the insulating layer uneven, and furthermore, if the resin in the resin pool spills out to the outside before being heated and hardened. This is because there is a high risk that voids will occur in this part, resulting in a decrease in electrical properties and mechanical strength, and becoming a weak point in the insulation.

Therefore, as the insulating tape to be used, laminated mica tape, which has a uniform thickness, is highly flexible, and is easy to wrap closely around the coil conductor, is preferred and generally used, compared to flake mica tape, which has large mica pieces and uneven thickness. There is. There are two types of aggregated mica: a fired type obtained by firing mica pieces at a high temperature of 600'C or higher, and an unfired type obtained by mechanically crushing mica pieces using a water jet method. The dimension (referred to as aspect ratio) of the mica particles in the surface direction relative to the thickness is small in the fired type and slightly larger in the unfired type. Therefore, the characteristics of a laminated mica tape or laminated mica sheet, which is made of glass fiber cloth, polyester fiber cloth, polyester nonwoven fabric, etc. as a backing material and a laminated mica layer is attached to the backing material by a small amount of resin, are uniformity of dimensions, The fired type is superior in terms of flexibility and withstand voltage characteristics, and the unfired type is superior in terms of resin impregnation and mechanical strength, but the unfired type has some dimensional non-uniformity and flexibility. Because of the inferior quality, the tape tends to loosen or wrinkle when wound with a tape, and the insulating layer tends to have resin accumulations and voids.

In the case of a surface pressure coil manufactured using the fully impregnated insulation method, the surface of the coil insulation is fixed to the core slot part by the impregnated resin, so the thermal expansion and contraction of the coil conductor and the core during operation and stop of the rotating electric machine is prevented. The difference causes mechanical stress inside the insulating layer. In addition, this mechanical stress tends to be greatest in the middle □ layer of the coil insulation layer because both sides of the insulation layer 4 are restrained by the conductor and the iron core. Therefore, if the aforementioned resin pool or peeling of the insulating layer is present in this portion, there is a risk that the weak point will expand due to the stress.

Therefore, it is thought that it is possible to improve the reliability by intensively strengthening the mechanical strength in the central part of the insulating layer, but high-voltage coils with such a structure have not yet been put into practical use, and fired laminated mica A method of alternately forming tape layers and unfired laminated mica tape layers has been proposed, but no satisfactory performance has been obtained.

[Purpose of the invention]

This project was developed in view of the above-mentioned situation, and the purpose is to provide a high-voltage coil for a rotating electric machine manufactured using a full-impregnation insulation method that has excellent voltage resistance and mechanical stress resistance.

[Key points of the invention]

This invention provides an insulating layer made of a laminated mica tape made of a mixture of unfired laminated mica and synthetic fibers, which has higher retention of impregnated N resin and mechanical stress resistance than a conventional insulating layer made of fired laminated mica tape. Focusing on its superior properties, we placed an insulating layer made of unfired laminated mica tape or sheet mixed with synthetic fibers in the center of the thickness of the coil insulation, where mechanical stress caused by thermal expansion and contraction is concentrated. In addition to improving mechanical stress resistance, the high-voltage coil insulation is configured to suppress an increase in insulation thickness by placing a fired laminated mica tape layer with uniform thickness, flexibility, and good voltage resistance characteristics on both sides. It is something to do.

[Embodiments of the invention]

According to experimental studies by the inventors, 10 sheets each of fired mica sheets with a thickness of 0.16% with glass cloth as the backing material and unfired laminated mica sheets mixed with 5% by weight of aromatic polyamide fibers were stacked. In total [24%
After vacuum-impregnating the resin made of epoxy resin and acid anhydride with an impregnating resin containing a curing catalyst αθ5-layered part, which is a tertiary amine, one end surface of the stacked sheets was placed in a mold. The impregnated resin was heated and cured for 16 hours in a constant temperature bath kept at 130°C in a state in which the impregnated resin flowed freely to produce a laminate. The resin content of the obtained laminate was 30% by weight when a fired type sheet was used, and 40% by weight when an unfired type sheet mixed with synthetic fibers was used.
The resin retention rate of the laminate using unfired laminated mica sea 1- mixed with aromatic polyamide fiber is 1■ compared to conventional firing!
30% or more compared to FL1 tentative, which uses grown mica sheet.
[It has become clear that an insulating layer with fewer voids can be formed by using unfired laminated mica tape or seal l- mixed with synthetic fibers.

Furthermore, the fracture energy of the bending strength of the above-mentioned laminated plate is 30% higher than that of the laminated plate of fl13 using fired laminated mica sheet.
% and had more stable properties against mechanical stress.

FIG. 1 is a cross-sectional view of a high-voltage coil of a rotating electrical machine showing an embodiment of the present invention. In the figure, 1 is a thrower 1-iffl provided in the iron core of a rotating electric machine, and 2 is a wedge provided in the opening 1 of the slot portion 1. Two dSS cocoils 3 are inserted into the slot portion. The high-voltage coil 2 includes a coil conductor 4 having a quadrilateral cross section, each consisting of a plurality of insulated rectangular conductors, a fired laminated mica tape layer 5a closely wound on the outside of the coil conductor 4, and a An unfired laminated mica tape or sheet layer 6 made of a mixture of polyester fibers, aromatic polyamide fibers, etc. that is closely wound on the side, a fired laminated mica tape layer 5b that is tightly wound on the outside thereof, and In the example shown in the figure, the unfired laminated mica layer 6 provided at the center in the thickness direction of the insulating layer allows the fired laminated mica layer 5 to form 5a and 5b. It is divided into. Further, the two coils 2 are inserted into the slot 1 in an unimpregnated state through a low resistance slot liner ~8, and a wedge 3 is driven into the slot 1 to fix the coils 2 into the slot 1. The iron core of the converter with the coil 2 installed in this way is impregnated under vacuum and pressure with an impregnated resin such as Evogishi resin or polyester N resin using the total impregnation insulation method. The insulating layer of the high-voltage coil 2 is completed by heating and hardening under certain conditions, and is fixed to the inner surface of the slot 1 via a low-resistance slot liner 8.

The unfired laminated mica tape or sheet 6 described in the practical Mli example above is made of a blend of about 5 to 1% aromatic fibers <1 noamide fine or polyester fibers and unlit.
1 laminated mica layer, glass cloth, polyester fiber nj1
It is bonded to a backing material such as polyester with a small amount of resin, and the number of turns is determined by taking into account the size of the coil and the magnitude of mechanical stress. Alternatively, the unfired laminated mica layer may be divided into a plurality of layers and arranged alternately with the fired laminated mica tapes.

The ground insulation of the high-voltage coil constructed as described above has the following features compared to conventional insulation grooves. First, the fired laminated mica tape layer 5a is wound in contact with the coil conductor.
Because the tape has uniform dimensions and is highly flexible, it can be wound closely around the coil conductor, making it possible to form an insulating layer with excellent voltage resistance characteristics with less resin pooling and peeling of the insulating layer.

The same applies to the fired laminated mica tape layer 5b. On the other hand, the unfired laminated mica tape layer 6 has conventionally had an uneven thickness and is somewhat inflexible, so the shiko tape layer tends to loosen or wrinkle when winding the tape or inserting the coil into the slot, and when impregnated with resin. There were drawbacks such as the tendency for voids to occur due to resin accumulation and leakage of the impregnated resin. However, in the present invention, by using an unfired laminated mica tape mixed with synthetic fibers, the retention of the impregnated resin is reduced, as is clear from the actual Q results described in IJ. Even if it is possible, there is less resin leakage, so there are fewer voids, and the unfired laminated mica layer is reinforced with synthetic fibers, so the laminated mica layer does not peel off even when the tape is wound with force. Looseness and sagging of the tape layer are reduced, and as a result, the resin stagnation itself is eliminated, making it possible to form a uniform insulating layer.Therefore, the fired laminated mica tapes 5a and 5b have high mechanical strength and are free from voids etc. An unfired laminated mica tape M6 containing no defects was formed, and it became possible for the unfired laminated mica tape layer 6 to retain the mechanical stress caused by the cooling and heating cycles of the coil conductor.

Further, for the composite w4#i to be mixed with the unfired laminated mica, aromatic polyamide fibers or polyester fibers can be used depending on the maximum operating temperature of the coil conductor.

Furthermore, when the mechanical stress acting on the coil insulating layer is large, the mechanical strength of the insulating layer can be further strengthened by using a baked laminated mica tape mixed with synthetic fibers.

〔Effect of the invention〕

According to the present invention, we have focused on the fact that an unfired built-up mica tape or sheet mixed with synthetic fibers has excellent retention of impregnated A2F Ijj7 and mechanical stress resistance, and is also excellent in tape winding workability, The above insulating layer is placed in the middle of the insulating layer where defects such as penetration of the insulating layer are likely to occur due to mechanical stress generated by the body's cooling and heating cycles, and the insulating layer is uniform on both sides and has high dielectric strength. By disposing the fired laminated mica tape layer, it is possible to provide a II-pressure cocoil with fewer defects in the insulating layer, no defects caused by mechanical stress, and excellent withstand voltage characteristics. In particular, in the case of long high-voltage coils manufactured using the full-impregnation insulation method, the mechanical stress acting on the insulation layer is large.
If there are resin pockets or voids in the insulating layer, stress will concentrate in these areas, expanding the weak point, and sometimes there is a high risk that the insulating layer will break, but the insulating M4 structure of the present invention can be applied. As a result, the second danger is eliminated, and a highly reliable long high-voltage coil can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a high voltage coil showing an embodiment of the present invention. 2... High voltage coil, 4... Coil conductor, 5... Fired laminated mica tape layer, 6... Unfired laminated mica tape layer mixed with synthetic delicate material.

Claims (1)

[Scope of Claims] 1) A high-voltage coil for a rotating electric machine in which a mica tape assembly is wound a predetermined number of times in close contact with a winding conductor made of a plurality of insulated conductors, and then impregnated with resin by a total impregnation insulation method. The laminated mica tape layer is composed of a fired laminated mica tape layer and an unfired laminated mica tape layer or sheet layer made of a mixture of synthetic fibers, and the unfired laminated mica layer is interposed in the middle of the fired laminated mica tape layer. A high-voltage coil for rotating electric machines featuring: 2. In the high voltage coil according to claim 1,
A high-voltage coil for a rotating electrical machine, characterized in that the synthetic fiber is polyester fiber or aromatic polyamide fiber. 3) In the high voltage coil according to claim 1,
A high-voltage coil for a rotating electric machine, characterized in that the fired laminated mica tape layer is made by mixing synthetic W4 male.