JPS586054A - Manufacture of coil for rotary electric machine - Google Patents

Abstract

PURPOSE:To prevent the production of a corona in a slot by winding a low resistance tape formed by bonding a glass cloth and a film on the outer periphery of a coil, providing a corona shield layer in contact with the tape and then immersing resin. CONSTITUTION:A low resistance tape formed by coating and baking low resistance paint on a sheet bonded with a glass cloth 9a and a film 9b is wound on the outer periphery of a coil 1 from the end of the slot to the outside of the slot, thereby forming a conductive layer 9. A corona shield layer 5 is provided at a coil end part in contact with the layer 9, and a protecting layer 6 is provided on the outer periphery. Then, insulating resin is eventually immersed. In this manner, even if the resin is immersed at the glass cloth 9a, the film 9b is maintained in the low resistance state. Accordingly, the corona in the slot can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for insulating a coil of a rotating electric machine, and particularly to prevention of corona inside a slot of a winding.

Figure 1 is a vertical cross-sectional view of a coil with conventional corona prevention measures, in which the coil conductor 1 is covered with an insulating layer 2, the part inserted into the iron core 3, and the part slightly protruding from the end of the iron core 3. Low resistance for corona prevention (102~103Ω/cIn)
The coil end part located outside the iron core 3 that connects the four electric layers 4 is a brown resistor (10@
Cover with a corona shield layer 5 of ~10''Ω/crIL).

Additionally, this corona shield layer 5 also covers the ends of the 4 electric layer 4 for corona prevention.
A protective layer of 6'ft is provided over the entire structure to prevent resistance fluctuations due to mechanical damage or resin impregnation. The conductive layer 4 for preventing corona is coated with a conductive paint, or is made of glass cloth, film, non-woven fabric, etc. coated with a conductive paint and wound with a tape. The corona shield layer 5 at the coil end is coated with a high-resistance paint (containing graphite or carbon black, etc.) and then wrapped with tape or asbestos tape made by applying this paint to all glass cloth, film, non-woven fabric, etc. Use the one you made.

The protective layer 6 is also formed by applying a paint having the same resistance characteristics as the corona shield layer 5 or by winding a plastic film around it. The in-slot conductive layer 4 of the coil with such a configuration as a corona prevention measure is a sheet with a surface cloth,
When applying the vacuum pressure impregnation treatment method, the cloth or resin adheres to the surface of the conductive layer 4 or permeates into the layer, causing the resistance value to fluctuate, but generally increases, resulting in insufficient contact with the iron core 3. In this case, corona discharge will occur between the conductive layer 4 and the iron core 3 at a relatively low voltage, and the corona shielding effect will be impaired. Particularly in the case of tapes made by applying low-resistance paint to glass cloth, non-woven fabric, etc., the resin tends to penetrate between carbon particles or between graphite and cloth, which tends to impair the corona shielding effect. In addition, when a film is coated with a low resistance paint, the film tends to stretch when being wound, so the conductive layer 4 is likely to peel off and the resistance value is likely to fluctuate. Applying low-resistance paint to the coil surface is less of a problem in the prepreg method, but in the case of vacuum impregnation, especially the total impregnation method, paint cannot be used and tape must be used. Figure 2 is a characteristic curve diagram of voltage and tan a.
The coil exhibits the characteristics of a coil in which the corona shielding effect is impaired in the above-mentioned state, but tan δ increases dramatically at a low voltage as described above, and there is a drawback that the corona suppressing effect is impaired.

An object of the present invention is to provide a method for insulating a rotary electric coil, which eliminates the above-mentioned drawbacks and improves the corona shielding effect.

The structure of the present invention will be explained below with reference to FIG. 3 of one embodiment. As a conductive material for preventing corona inside the slot, a tape (resistance value 102 to 103 Ω/bor) made by applying and baking a low-resistance paint to a sheet made by pasting glass cloth 9a and film 9b is wound around a conductive material. The layer is applied over the entire surface of the insulating layer 20 from the core insertion portion of the conductor 1 and the end of the core 3 to several tens of meters outside. Following this, the connected coil end has high resistance for corona prevention (106 to 1
08Ω/cTL) corona shield layer 5 and protective layer 6
administer. After this is inserted into the slot fC of the iron core 3, the rotary electric machine coil is insulated by being impregnated with coil surface treatment varnish or coil impregnating resin and hardened. conductive layer 4
The paint is, for example, a paint made by suitably blending silicone distomer with carbon as a conductivity imparting agent and aluminum powder for paint, and is applied to a sheet made of glass cloth and film to make a tape.

This tape is attached to the glass cloth 9a against the insulating layer 2 of the conductor l.
It does not matter which side of the film 9b is in contact with each other.

According to the insulation treatment method with the above structure, even if the surface burr filling varnish or the coil impregnation resin invades the slot circle of the iron core 3, the glass cloth 9a side will be damaged on the surface or in the layer at %t1w9 as in the conventional case. Even if the resistance value increases due to intrusion or adhesion of resin, etc., the film 9b side is not covered by the glass cloth 9a.
Unlike the glass cloth, the low-resistance paint completely adheres to the surface of the film 9b side and the bonded part of the film 9b and glass cloth 9a, forming a dense conductive layer, so there is no cross-like gap. Since the original resistance value of the resistance tape can be maintained at 10" to 103 Ω/cmf during processing, the corona suppressing effect in the slot of the iron core 3 can be sufficiently exhibited. 8, and it can be seen that the corona suppressor 1j in the slot is sufficiently effective and has good characteristics.

In addition, in the present invention, when making a low resistance tape, glass cloth 4
A total of 1 tapes made by pasting together low-resistance paint that has been applied and hardened to each of a and film 4b.
Similar effects can also be obtained by winding this around the entire surface of the coil insulating layer 2. Further, as the laminating film 9b, a shrinkable film or a non-shrinkable Δ film may be used, and the same corona suppressing effect as described above can be obtained.

As described above, according to the present invention, even if the cloth penetrates into the slot, it is possible to achieve low resistance, thereby preventing the generation of corona inside the slot of the coil. It has a positive effect.

[Brief Description of the Drawings] Fig. 1 is a vertical cross-sectional view of a conventional iron core end and coil, Fig. 2 is a voltage-tan δ characteristic curve diagram of a rotating electric machine coil, and Fig. 3 is an iron core end and coil of the present invention. This is the vertical cross section of 1.

Claims (1)

[Claims] A conductive layer made of a low-resistance tape made of glass cloth and film is attached to the core slot insertion part of the rotating electrical machine coil, and a high-resistance corona shield layer is connected to the coil end, covering this. After applying a protective layer,
A method of manufacturing a rotating electrical machine coil by impregnating and curing a thermosetting resin.