JPS6074950A - Insulating method of rotary electric machine coil - Google Patents

Abstract

PURPOSE:To obtain an excellent insulating coating for a partial electric discharge by bonding mica powder to an electric wire such as glass-coated wire or an enameled wire. CONSTITUTION:Glass fibers are wound and covered in a double manner on a flat conductor to form a glass-covered wire. The glass-covered wires are wound in two rows by twelve turns, thereby obtaining a coil 3 for a rotary electric machine. The necessary portion of the coil 3 formed in this manner is dipped in varnish. The coil 3 which is completed in the dipping of the varnish is pulled up from a varnish dipping tank, the varnish is removed, and mica powder 7 is coated on the coil. After the powder 7 is bonded, the powder is cured and molded to obtain the surface insulating layer of the coil. Thus, the coil for the rotary electric machine for high voltage having good partial discharge characteristic can be readily manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention improves the partial discharge resistance of rotating machine coils.
15 Regarding the edge method.

Conventionally, mica-based insulating tape, which has excellent voltage resistance and partial discharge resistance, has been used to insulate the conductors of rotating machine coils used at high voltages such as 6.6kV and 11kV.

It is. The mica used here is generally a composite mica because it has small variations in thickness and withstand voltage characteristics, and is bonded with varnish using glass cloth or an insulating film as a backing material and processed into a tape. This tape is wound around a conductor to form an insulated wire, which is then rolled into a pattern.
After being molded into a predetermined shape using a molding machine, the outer surface is provided with a predetermined ground insulation depending on the voltage used to complete the rotating machine coil.

However, mica-based insulated wires have poor workability compared to fiber-covered or enamel-baked wires, the production cost of insulated wires is relatively high, and alpha rays have not yet been baked and hardened, so they can be molded. There is a problem that it is easy to get scratched during work, so it takes time and effort to repair the scratches.

The present invention has been made to improve such problems, and by attaching mica powder to commonly used and easy-to-work 'G&L' wires such as glass-coated wires (e.g. DGC wires) or enameled wires, partial discharges can be prevented. The present invention provides a method for obtaining an excellent insulating coating for various types of materials, and the content of the present invention will be explained in detail by one embodiment using the drawings.

FIG. 1 is a cross-sectional view of the core slot of a rotating machine coil, with the ground insulation removed.

In this example, the DGCm, which is made by winding fine glass l twice around the rectangular conductor 2, is wound in two rows to form 12 turns.
ffl coil 3. As is well known, the '1·L field tends to concentrate at the corners, so it is obvious that countermeasures against partial discharge should be taken on the outer surface of the coil 3.

FIG. 2 is a plan view of one rotating machine coil, and as shown in FIG. Length A including the length C between the end faces B of the laminated core indicated by the chain line
It is composed of a 1M wire portion 3a, a coil end portion 3b, and a coil eye portion 3C.

The electric field strength is particularly high at the end face B of the layered core.
Next, the electric field strength at the length C in the core slot and its vicinity is high, and the electric field strength at other parts such as the coil end 3b is relatively low, so as a countermeasure against partial discharge, the straight line of the coil 3 is It is only necessary to perform this on part 3a.

A necessary portion of the coil 3 thus formed is immersed in varnish. Note that in this example, the insulation is a wire and DGCa
was used, but the same applies when enamelled wire is used.

Dipping varnishes include epoxy-based varnishes, polyester-based varnishes, and imide threads, and these varnishes can be broadly classified into solvent-based and non-solvent-based varnishes. Either type of varnish can be used, but when using fiber-coated insulating alpha rays,
A varnish of the same type as the one used to adhere the coating is generally compatible, and in the case of this method, a solvent-free varnish is preferable.

The viscosity of the varnish at the time of dipping is conveniently 80 to 400 CP; if the viscosity is higher than this, it is advisable to preheat the coil 3 and dipping in a warm state. Of course, you can warm up the varnish, but be careful when doing so, as the pot life of the varnish may be shortened.

FIG. 3 is a cross-sectional view taken at the center of the coil showing the state of immersion in varnish. The varnish immersion tank 5 has a length equal to or greater than the length of the straight part 3a of the coil 3, and has an IC configuration in which only the part corresponding to the coil pitch is deepened so that the straight part 3a on both sides can be immersed in the varnish at the same time. The varnish 4 as described above is filled and the powder part 3a of the coil 3 is immersed.

The reason why the varnish immersion tank 5 in which only the straight coil portions 3a on both sides can be immersed is used is to save on the use of varnish, and the entire coil except for the exposed portion 3C may be immersed. . The soaking time should be as long as the soaked part is completely covered, and the soaking should be completed within 2 to 3 minutes. After completing the immersion in the varnish, the coil 31 is pulled up from the maternity varnish dipping tank 5, the varnish is removed, and then the work of sprinkling mica powder begins.

FIG. 4 is a cross-sectional view at the center of the coil showing the state in which the coil is fluidized into mica powder. Streaming II dipping device 6 into which at least both straight paddy portions 3a of the coil 3 can be inserted simultaneously
When mica powder 7 is placed in the container and compressed air G is passed through a fine fill 8 provided at the bottom, the mica powder 7 floats up to the point where its own weight is buffed by the pushing up force of the compressed air.

The appropriate size of the mica powder (used) is about (11-1 mm). After removing the drops, hang the coil 3 or place it so that it is supported by the head of the coil end 3b, and sprinkle mica powder 7 on the part of the coil 3 that was covered with varnish 4. Make it adhere.

When the mica powder 7 no longer adheres, pull up the coil 3 and immediately apply a heat-resistant release film (for example, a polyester film coated with a silicone release agent on one side) to the 1-section line 3a. Roll the sushi to length A and secure with adhesive tape.

Using the coil 3 treated in this way, the varnish 4 (suitable temperature) can be applied to the eaves! ] If the linear part 3a is inserted into a heat-brace casing, and then hardened and molded to the specified dimensions, a coil suitable for use in the Karasugai pressure direction with partial radiation resistance characteristics can be obtained. It is possible to obtain an insulated layer.

The outer surface of the coil 3 thus formed is further insulated to a predetermined level according to the voltage I used in conventional products, thereby completing the rotating machine coil.

In addition, the method of sprinkling the mica powder 7 is as described above.
In addition to the method of using an ffl tank, it is also possible to use a method of spraying, a method of sprinkling by hand, and the like. It is also possible to automate the entire process from varnish dipping to heat-brushing and have it done by hand.

In the straight part 3a of the coil of this embodiment manufactured as described above and before being insulated to ground, aluminum foil is wrapped around the length C corresponding to the inside of the slot to form a ground electrode, and the coil outlet is By applying various alternating voltages to 3C and determining the relationship between the applied voltage and breakdown time, that is, V-tq4f, the results were almost the same as those of a conventional product using an insulated wire wrapped with laminated mica tape. I was able to get it.

In the above explanation, the basic fi! which is wound as a coil! Although the case where an insulated conductor is used has been described, it is also possible to apply the method according to the present invention by winding and forming a rotary coil using a conductor. After the bare conductor is wound around a winding form in a predetermined manner, it is put into a molding machine to form a hexagonal shape Cζ, and the entire coil is immersed in varnish.

In this case, it is necessary to apply mica powder not only to the straight part but also to the entire coil except for the sunrise part.

Therefore, by immersing the entire coil in varnish, spreading the coil into a coil spring shape, removing drippings, and placing the entire coil in a fluidized dipping bath, it is possible to apply a layer of mica powder to each strand.

After taking it out from the fluidized immersion tank, it is returned to its original molded state, a release film (F14 is a film made of polypropylene, a copolymer of polyethylene terephthalate, and polyethylene) is wrapped around the entire coil, and the coil ends are further heated. Wrap shrink tape (for example, polyester woven tape). Next, the straight part of the coil is placed in a heat press machine, and after being heat pressed and hardened to the specified dimensions,
If the varnish at the end of the coil is cured by drying the entire coil with P7, it is possible to manufacture a high-quality rotating machine coil even from bare conductors.

As explained in detail above, according to the insulating treatment method for a rotating machine coil according to the present invention, it is possible to easily produce a high-voltage rotating machine coil with good partial discharge resistance using an inexpensively available coil. It becomes possible to manufacture.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the core slot of the rotating machine coil, and Fig. 2 is a plan view of one rotating machine coil, fA3
The figure is a cross-sectional view at the center of the coil showing the state of immersion in varnish, and the M4 figure is a horizontal r-section view at the center of the coil showing the state of fluidized immersion of the coil in mica powder. l... Glass fiber, 2... Flat conductor, 3... Coil, 4... Varnish, 5... Varnish fflf
f1m, 6...Fluid anti-pickling powder, 7...Mica powder, 8...Filter O Patent applicant Toyo W Ki Seizo Co., Ltd. Representative Doi Atsutame 21 Gentaku, 31Z

Claims (1)

[Scope of Claims] 1. A conductor made of inorganic or organic fiber and baked with varnish, or a conductor with baked enamel film, rolled and formed, treated with varnish to remove drips, sprinkled with mica powder, hardened, and formed. An insulating treatment method for rotating machine coils that is characterized by 2. Special if the mica powder sprinkling work is done using the flow 1i II + dipping method! A method for insulating a rotation range coil according to item 1 of I-Claim & Disciple.