JPH08242563A - Manufacture of insulating coil for rotary electric machine - Google Patents

Abstract

PURPOSE: To provide a method by which an insulating coil for rotary electric machine which is improved in th resin impregnability of the insulation-to-the- earth layer of the coil, can prevent the leakage of the resin from the insulating layer, and has an excellent electric field resistance and from which the formation of voids is eliminated can be manufactured. CONSTITUTION: An unimpregnated insulating coil 3 formed by winding an insulation-to-the-earth layer 10 formed by winding a mica insulating tape processed with an epoxy silane coupling agent and leakage preventing layer 9 formed by processing an epoxy resin and granular latent cure accelerator formed in micro-capsules around an element-wire conductor bundle 1 is mounted in the slot of a stator core and the coil is integrally impregnated with a resin composed of an epoxy resin and acid anhydride curing agent. After impregnation, the resin is cured by heating the coil 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an insulating coil for a rotating electric machine, and more particularly to a method for manufacturing an insulating coil for a rotating electric machine obtained by completely impregnating a stator insulating coil housed in an iron core slot of a high voltage rotating electric machine with an impregnating resin.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a stator insulating coil of a conventional high voltage rotating machine. As a method of manufacturing an insulating coil of a rotary electric machine, there is a full impregnation insulation method in which the insulating coil is housed in an iron core slot, and the insulating coil and the iron core are integrally impregnated with a resin and cured. This full impregnation insulation method, as shown in FIG.
First, a wire conductor with insulated wire is wound a plurality of times to produce a wire conductor bundle 1, and a mica foil having excellent electric field resistance is fired on the wire conductor bundle 1 or crushed by a high-pressure water stream or the like. The grounded insulation layer 2 is formed by winding mica insulation tape, which is made by woven fabric or film made of glass fiber etc. as a backing material with a small amount of binder such as epoxy resin, etc., around the mica that is made into fine scales and made into paper. An unimpregnated insulating coil 3 not impregnated with the resin is manufactured. Next, this non-impregnated insulating coil 3 is mounted in the iron core slot 5 of the stator core 4 together with auxiliary materials such as interphase insulation 6 and wedges 7, and after each insulating coil 3 is connected, it is installed in a resin impregnation tank. Then, an impregnated resin made of a thermosetting resin is integrally impregnated by vacuum and pressure, then taken out from the resin impregnation tank and cured in a heating and curing furnace.
As the thermosetting resin of the impregnating resin, epoxy resin, unsaturated polyester resin, polyimide resin, etc. are applied.
Epoxy resin, which is well-balanced in thermal, mechanical and electrical properties after thermosetting, is often used. In the stator insulating coil of the high-voltage rotating electric machine, a low resistance (not shown) is provided between the insulating coil 3 and the stator core 4 in order to prevent occurrence of partial discharge (corona discharge) due to poor electrical contact. A surface corona preventive layer is provided.

In the insulation coil of a high-voltage rotating machine of the full impregnation insulation system, a high voltage is applied, so that a dense insulation layer sufficiently impregnated with resin is formed inside the ground insulation layer to generate partial discharge. It is necessary to form a uniform insulating layer without voids that cause Therefore, the impregnating resin used for the full impregnation insulation is required to have a low resin viscosity in order to improve the impregnation property into the ground insulating layer.

In order to reduce the viscosity of the above impregnated resin,
It is common practice to heat the impregnated resin during the total impregnation. By the way, the resin impregnation of the insulated coil by this full impregnation method requires a large amount of impregnated resin in order to impregnate the whole stator iron core 4 in which the unimpregnated insulated coil 3 is inserted into the iron core slot 5 with the resin impregnation tank. , Use again. Therefore, it is necessary to select a stable resin having a small increase in viscosity in order to avoid impregnation into the ground insulating layer due to an increase in viscosity of the impregnated resin due to repeated impregnation. For this reason, a resin system is used in which the impregnating resin is composed of a thermosetting resin made of an epoxy resin and an acid anhydride curing agent, and does not contain a curing accelerator that accelerates the curing reaction. In this case, the above-mentioned curing accelerator is applied to the mica insulating tape constituting the ground insulating layer 2 so as to accelerate the curing reaction of the impregnated resin impregnated in the ground insulating layer 2 during heat curing. In addition, a method of impregnating at a low temperature (30 to 40 ° C.) near room temperature is also adopted to avoid an increase in viscosity of the impregnated resin due to heating, and a low viscosity resin containing a low viscosity epoxy resin or a low molecular weight epoxy resin is blended. It has also been used.

[0005]

By the way, as described above, the lower the viscosity of the impregnating resin is, the better the impregnation property of the resin into the grounding insulating layer of the insulating coil is. The wettability between the laminated mica and the base material of the backing material is also greatly affected. That is, since the surface tension of the bonding resin and the impregnated resin, which are bonded to the laminated mica and the glass cloth that constitute the mica insulating tape of the ground insulating layer, is high, the wetting with the mica insulating tape is performed. However, there is a problem in that the repelling of the impregnated resin has a small property, and an unimpregnated portion where the resin does not adhere to the mica insulating tape partially occurs. Furthermore, when the thermosetting resin impregnated resin made of epoxy resin is impregnated into the non-impregnated insulating coil 3 and then is heat-cured together with the stator core 4 in the curing furnace, the resin viscosity decreases and the ground insulating layer 2 The phenomenon that resin leaks more is seen. The leakage of the resin from the ground insulating layer 2 is also affected by the wettability between the mica insulating tape forming the ground insulating layer 2 and the resin. If the wettability is poor, the resin is bonded at the interface with the mica insulating tape. Since the force is weak, the resin easily flows out from the ground insulating layer 2, which promotes adhesion failure between the mica insulating tapes of the ground insulating layer 2 and generation of the unimpregnated portion 8.

As a measure for preventing the resin impregnated in the ground insulating layer 2 from leaking, a curing accelerator is pretreated on the mica insulating tape so that the curing reaction with the resin impregnated in the mica insulating tape is performed at the time of heat curing. A method of hardening the impregnated resin to eliminate the fluidity by promoting it is also adopted.
However, due to repellency of the resin due to the small wettability of the resin to the mica insulating tape, an uneven non-impregnated portion is generated, and therefore, it is possible to completely generate minute voids in the ground insulating layer after heat curing. It couldn't be resolved.

The object of the present invention is to improve the wettability of the mica insulating tape forming the ground insulating layer of the rotary electric machine insulating coil with the impregnated resin and the resin permeability, so that the resin impregnability is good. Accordingly, it is an object of the present invention to provide a method for manufacturing an insulating coil having excellent insulating performance, which prevents the leakage of resin from the insulating layer of the insulating coil during heat curing and does not generate voids.

[0008]

In order to solve the above-mentioned problems, the present invention treats a laminated mica and a glass cloth base material with an epoxy-based silane coupling agent and bonds them with an epoxy resin. Make up the insulating tape,
This insulating tape is wound around the outer circumference of a wire conductor bundle, and an unimpregnated insulating coil provided with a ground insulating layer is integrally impregnated with an epoxy resin and heat-cured.

It is preferable that the epoxy silane coupling agent for treating the above-mentioned mica and glass cloth base material is γ-glycidoxypropyltrimethoxysilane.

Further, a resin leakage prevention layer is provided on the outermost layer of the non-impregnated insulating coil provided with the ground insulating layer, which is provided with a latent curing accelerator which is melted by heating to the woven fabric and the nonwoven fabric and undergoes a curing reaction with the impregnated resin. I shall.

Further, it is more preferable that the latent curing agent constituting the resin leakage prevention layer is a microcapsule whose surface is covered with a resin melted by heating.

[0012]

The present invention is a mica insulating tape prepared by selecting an epoxy-based silane-based coupling agent having an organic functional group that is particularly easy to react with a resin as a silane coupling agent, and treating the selected silane coupling agent with glass mica. Was prepared, and this mica insulating tape was wound around a wire conductor bundle to form a ground insulating layer. Thereby, by the binding force generated by the reaction between the impregnated epoxy resin and the organic functional group of the epoxy-based silane coupling agent treated on each substrate of the glass cloth that is mica and this backing material. ,
By improving the wettability of the mica insulating tape with the epoxy resin, the permeability and diffusibility of the resin during resin impregnation are improved, and the retention of the epoxy resin in the insulating layer is improved. This prevents the resin unimpregnated part from occurring in the ground insulation layer, prevents the resin from leaking from the insulation layer during heat curing, and prevents the formation of voids inside the ground insulation layer. Becomes

Further, by using γ-glycidoxypropyltrimethoxysilane as the epoxy-based silane coupling agent, in addition to the organic glycidoxy group which reacts with the epoxy resin, inorganic substances such as mica and glass cloth are used. Since it has a methoxy group on the inorganic side that forms a covalent bond with the epoxy resin and the mica insulating tape, by strengthening the binding force between the mica and the glass cloth that compose the mica insulating tape, adhesion between the epoxy impregnated resin and the mica insulating tape You can improve your strength.

Further, as a means for preventing resin leakage from the ground insulating layer at the time of heat curing, the outermost layer of the insulating coil is treated with a latent curing accelerator which is melted by heating and undergoes a curing reaction with the impregnated resin. By providing a resin leakage prevention layer made of a material, the reaction between the impregnated resin and the latent curing accelerator of the resin leakage prevention layer described above is promoted to form an insulating layer that has undergone a curing reaction. It is possible to prevent the impregnated resin in the insulating layer, whose viscosity is sometimes reduced, from leaking to the outside.

By using the latent curing agent forming the resin leakage prevention layer described above, a microencapsulated latent curing accelerator in which the heating curing accelerator is covered with a resin that melts at the heating curing temperature of the insulating coil is used. In addition, the storage stability is good, and it is possible to prevent deterioration of the curing accelerator due to moisture absorption. In addition, it is possible to prevent the formation of the resin leakage prevention layer from being hindered due to the decrease in the curing reactivity due to the adsorption of the moisture of the curing accelerator during the heat curing of the impregnated resin.

[0016]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a sectional view of a stator insulating coil 3 of a high voltage rotating electric machine according to an embodiment of the present invention. In addition, the figure is the conventional FIG.
The same reference numerals are used for the same parts as the conventional one, and detailed description thereof will be omitted.
In FIG. 1, the ground insulating layer 10 of the insulating coil 3 is obtained by winding a mica insulating tape in which a glass cloth as a backing material is pasted on a laminated mica for a predetermined number of times in a wire conductor bundle 1 formed by winding a plurality of wire conductors. Is configured. The production of the above-mentioned mica insulating tape is as follows.

Γ-Glycidoxypropyltrimethoxysilane SH6040 (manufactured by Toray Dow Corning Silicone Co., Ltd.) was used as an epoxy-based silane coupling agent for treating the insulating tape, and this was made to be 3% by weight in ion-exchanged water. A dissolved aqueous solution was prepared. Next, the laminated mica sheet and a base material on which a glass cloth is laminated as the backing material are sandwiched between fine metal meshes and immersed in an aqueous solution containing the above-mentioned epoxy silane coupling agent to impregnate the aqueous solution. Removed from the oven at 125 ° C for 1
Let dry for hours. The dried and laminated base material is peeled off again, and the sheet in which the laminated mica sheet and the glass cloth are attached to the laminated mica sheet with the epoxy resin binder of 5% by weight is cut into a tape to insulate the mica. Got the tape. The above-mentioned epoxy resin binder has a predetermined amount of an accelerator that promotes a heat curing reaction of an impregnating resin composed of an epoxy resin containing two or more epoxy groups, an epoxy resin described later, and a resin mixture of an acid anhydride curing agent. There is. This accelerator can be selected from metal salts, imidazoles, and tertiary amines.

As shown in FIG. 1, the above-mentioned mica insulating tape is wound around the wire conductor bundle 1 a predetermined number of times to form a ground insulating layer 1
No. 0 was constructed, and the leakage preventing layer 9 was wound around the outermost layer of the ground insulating layer 10 to produce an unimpregnated insulated 3 coil. The leak preventive layer 9 contains a mixed resin of an epoxy resin and an acid anhydride curing agent and an imidazole-based latent curing accelerator in an amount of about 8%.
Novacure HX3742 (Asahi Kasei Kogyo Co., Ltd.) having a particle size of several μm and microencapsulated with a resin that melts at 0 ° C.
A non-woven glass fabric was immersed in a liquid in which was dispersed and prepared.

The unimpregnated insulating coil 3 is mounted and installed in the core slot of the stator core together with auxiliary materials such as interphase insulation and wedges through a surface corona preventive layer (not shown) as in the conventional case (FIG. 4). reference). The impregnating resin that completely impregnates the insulating coil 3 and the stator iron core inserted in the iron core slot is liquefied by mixing the epoxy resin of bisphenol A and the acid anhydride curing agent into the impregnation tank. At 30
After being heated to ° C and integrally impregnated by vacuum / pressure impregnation, the stator was taken out from the impregnation tank and heat-cured at 140 ° C in a heat-curing furnace to produce a stator insulating coil.

FIG. 2 shows the partial discharge voltage characteristic I of the above-mentioned fully impregnated insulating coil according to the present invention, which is provided with a ground insulating layer having a rated voltage of 6 kv, and shows the conventional epoxy-based silane coupling agent according to the present invention. Of an insulating coil produced by the full impregnation method in the same manner as in the present invention described above using an uncoated mica insulating tape and an insulating coil having no outermost resin leakage prevention layer 9 of the ground insulating layer. Illustrated in comparison with II. The characteristic I of the insulating coil of the embodiment of the present invention is significantly improved as compared with the characteristic II of the conventional insulating coil in both the partial discharge inception voltage and the maximum discharge charge amount in the ground insulating layer. Observation of the cross section of the coil also confirmed that there was no large void in the ground insulating layer and that a dense insulating layer was formed.

For reference, FIG. 3 illustrates the effect of the wettability of the resin with respect to the mica of the epoxy silane coupling agent used in the examples of the present invention. The wettability was evaluated by adding the silane coupling agent to ion-exchanged water in an amount of 0.5 to 6
Dip the mica foil in the solution dissolved by weight% to process
On the surface of the mica foil obtained by drying at 125 ° C for 1 hour,
It was carried out by dropping the impregnating resin containing the epoxy resin of bisphenol A and the acid anhydride curing agent, and measuring the contact angle between the dropped resin and the mica foil. That is,
The smaller the contact angle is, the smaller the surface tension is, the easier it is to diffuse on the mica foil surface, and the larger the wettability is. A is an epoxy silane coupling agent of γ-glycidoxypropyltrimethoxysilane of the present invention, and B is γ- (2-aminoethyl) aminopropyltrimethoxysilane SH6020 (Toray Dow Corning Silicone Co., Ltd.), and C is a characteristic of using a mica foil not treated with a silane coupling agent. A of the mica foil treated with 3% by weight or more of the epoxy-based silane coupling agent is about 1 / m of the untreated mica foil C.
The contact angle is 5 and the effect of improving the wettability of the epoxy resin to the mica foil is great. However, it can be seen that the amino-based silane coupling agent B has a small effect.

[0022]

As described above, according to the present invention, the mica insulating tape, which is wound around the wire conductor bundle to form the ground insulating layer, is made of the laminated mica and glass cloth treated with the epoxy silane coupling agent. It consisted of and. As a result, the organic functional group of the epoxy-based silane coupling agent reacts with the impregnated epoxy resin to improve the wettability between the mica insulating tape and the epoxy resin, and the resin permeability and diffusion during resin impregnation. To improve the retention of the epoxy resin in the ground insulating layer. As a result, the generation of unimpregnated portions of the resin was reduced, and it was possible to prevent the generation of voids inside the insulating layer. Furthermore, since the wettability and diffusibility of the impregnated resin to the ground insulating layer can be improved, a homogeneous ground insulating layer can be obtained without impairing the impregnating property even with a resin having a higher viscosity at the time of impregnating the impregnating resin than before. Therefore, it is possible to lower the heating temperature during impregnation of the impregnated resin, which can suppress the increase in resin viscosity due to repeated use, improve the storage stability of the impregnated resin, and use the impregnated resin for a long time. There is also an economic effect of getting out.

Further, by using γ-glycidoxypropyltrimethoxysilane as the epoxy-based silane coupling agent, in addition to the functional group on the organic side that reacts with the epoxy resin, an inorganic substance such as mica or glass cloth is used. Since it has a methoxy group on the inorganic side that forms a covalent bond with, it is possible to increase the bonding force between the inorganic mica and the glass cloth, and to obtain a coil insulating layer with improved adhesion with the epoxy impregnated resin. be able to.

Further, by providing a resin leakage prevention layer comprising a base material treated with a microencapsulated latent curing accelerator covered with a resin melted by heating on the outermost layer of the ground insulating layer, the impregnated resin Since the insulating layer cured by the reaction with the latent curing accelerator of the resin leakage prevention layer can be formed on the outermost layer of the insulating coil, the viscosity increases due to the temperature rise during the curing reaction of the impregnated resin in the insulating layer. It is possible to prevent the resin that drops and flows from leaking from the ground insulating layer.

As described above, the rotary electric machine insulating coil according to the present invention can improve the impregnation property of the impregnated resin into the ground insulating layer and prevent the impregnated resin from leaking to the outside. An insulating coil having no void inside the insulating layer can be manufactured. Therefore, it is possible to eliminate the occurrence of partial discharge in the void portion, which causes deterioration of insulation particularly in the insulating coil of the high-voltage rotating electric machine, and to provide a highly reliable insulating coil. Further, since a dense and uniform insulating layer can be obtained, it contributes to the miniaturization of the rotating electric machine and the achievement of increased capacity by improving the thermal conductivity of the coil insulating layer.

[Brief description of drawings]

FIG. 1 is a sectional view of a stator insulating coil of a high-voltage rotating electric machine according to an embodiment of the present invention.

FIG. 2 is a partial discharge inception voltage characteristic of a stator insulating coil of a high-voltage rotating electric machine that is insulated according to the present invention and has a rated voltage of 6 kv.

FIG. 3 is a characteristic diagram of a contact angle between a mica foil treated with a silane coupling agent and an epoxy resin.

FIG. 4 is a cross-sectional view of a stator insulating coil of a conventional high voltage rotating machine.

[Explanation of symbols]

 1 Wire conductor bundle 2 Ground insulation layer 3 Insulation coil 4 Stator core 9 Leak prevention layer 10 Ground insulation layer

Claims (4)

[Claims] 1. A strand conductor bundle obtained by winding a strand conductor a plurality of times,
An unimpregnated insulating coil having a ground insulating layer provided on the outer periphery of this wire conductor bundle is housed in an iron core slot, and the unimpregnated insulating coil and the iron core are impregnated with thermosetting in an impregnation tank. In a method for manufacturing a rotating electric machine insulated coil, which is integrally impregnated with a resin and then heat-cured in a curing furnace, a laminated mica and a glass cloth base material are treated with an epoxy-based silane coupling agent, and these are treated with an epoxy. A mica insulating tape is formed by pasting together with a resin, and this mica insulating tape is wrapped around the outer circumference of a wire conductor bundle and the unimpregnated insulating coil provided with a ground insulating layer is integrally impregnated with epoxy resin and heat cured. A method for manufacturing a rotary electric machine insulated coil, comprising: 2. The method for manufacturing an insulating coil for a rotating electric machine according to claim 1, wherein the epoxy-based silane coupling agent is γ.
-Glycidoxypropyltrimethoxysilane, a method for manufacturing a rotating electric machine insulating coil. 3. The method for manufacturing a rotary electric machine insulating coil according to claim 1, wherein the outermost layer of the non-impregnated insulating coil provided with a ground insulating layer is melted by heating a woven fabric or a non-woven fabric by a heating reaction with the impregnated resin. A method for manufacturing a rotating electric machine insulated coil, comprising a resin leakage prevention layer containing a latent curing accelerator. 4. The method for manufacturing a rotating electric machine insulated coil according to claim 3, wherein the latent curing accelerator forming the resin leakage prevention layer is microencapsulated with the surface thereof covered with a resin melted by heating. A method for manufacturing an insulating coil for a rotating electric machine, comprising: