JPS59226641A - Manufacture of corona preventive coating of rotary electric machine - Google Patents

Abstract

PURPOSE:To simply and inexpensively form a corona discharge preventive coating by forming a high dielectric constant layer by a powder coating method after assembling a coil in a core. CONSTITUTION:An organic or inorganic or both combination insulating layer 2 is formed on a coil conductor 1, a low resistance coating 5 of a conductive material is formed from the portion introduced into a slot 4 to part of the vicinity fed out of the end of a core 3 and contained in the core 3. Then, powder of resin having coupling resin, 15-40% by weight of high dielectric constant filler such as barium titanate and having specific dielectric constant of 10-40 after curing is sprayed from nozzles 9-11 toward the core 3 and the coil end 13 to form a high dielectric constant corona preventive coating.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an anti-corona coating for preventing partial discharge of corona at the end of a stator of a rotating electric machine.

Generally, the stator coil of a high-voltage rotating machine is provided with ground insulation on the coil conductor using an insulating material made of an organic or inorganic insulating material or a combination of both, as shown in Figure 1.
A low-resistance coating made of a conductive material is provided on the insulating surface of the straight part of the stator core 3 that fits into the slotter in an area slightly longer than the core length to reduce the potential difference between the surface of the iron core 3 and the insulating layer of the coil. In order to prevent partial discharge due to corona, a corona prevention coating 6 is provided facing the coil end from a part that slightly matches the shape of the low resistance coating S, and the potential gradient at the end of the low resistance coating J is alleviated. This prevents corona discharge.

Conventionally, corona prevention coated cores have been mainly formed by the following method.

(T) Method of applying semiconductive high resistance paint.

(m) A method of winding and curing a tape made by impregnating glass tape or polyester cheese with a semiconductive high-resistance material.

(Tli method of using asbestos tape.

■ Method of applying resin containing high dielectric constant filler.

Among these methods, method (I) tends to cause uneven coating when applying the semiconductive high-resistance paint, and also uses resin such as epoxy for the coating process itself.

It was necessary to pay attention to the health of the workers. In method (n), it is difficult to produce a semiconductive high-resistance tape, and the tape unit price tends to be relatively high. Furthermore, the tape tends to float during winding, which may cause problems in adhesion. The asbestos used in method (to) is a material with good discharge resistance, but there is a problem that it is harmful to the human body, and in recent years there has been a trend towards regulating its use. A common problem among the above three methods is that due to the relaxation of the resistive electric field, heat generation is significant when a high voltage is applied for a long time, and the surface layer often burns out. On the other hand, the method using high dielectricity is an electrostatic field relaxation method, so the dielectric heat generation can be ignored at commercial frequencies. However, the common problem with the two methods T) to ■ is that it is necessary to work on the coil end of each coil, and the number of man-hours required is extremely large. Met.

The purpose of this invention is to provide a simple and inexpensive method for manufacturing a corona discharge prevention coating for a rotating electric machine that does not generate heat due to electric charge. This achieves the above objectives.

An embodiment of the present invention will be described below with reference to FIG.

An insulating layer made of organic, inorganic, or a combination thereof is applied to the coil conductor, and a low-resistance coating 3 of a conductive material is applied to the part that goes into the slot and the part that comes out from the end of the iron core 3. 3. connection insulation,
Perform coil binding.

Next, as shown in Figure 2, barium titanate (RaTL)
Powder powder containing O, y) particles as a main component and a bonding resin such as an epoxy resin is passed through the nozzles 9, 10. // to the iron core 3 and coil end /j [, and rotate the iron core 3 sequentially. This is a so-called powder coating method, and when done this way, as shown in Figure 1, a low-resistance coating comes out from the iron core 3! A corona prevention/inhibition coating 6 with a high dielectric constant is completed by overlapping the coil end L- and the coil end L-. In this case, it is best to preheat the part to be coated, and also use the nozzle 9.10. /
It is possible to make the film thickness more uniform than K by appropriately increasing the number of /. The same effect can also be obtained by rotating the nozzle instead of the iron core.

Next, the effect will be explained.

When using the powder coating method, the ridge where the coil is housed in the iron core 3,
A semiconductive high-resistance coating 6 can be formed, which is simpler and cheaper than conventional methods, and the coating 6 has excellent electrical properties without pinholes and has a uniform coating thickness. is obtained, and since the powder is solvent-free, it is non-polluting.
It has excellent processing efficiency, the coating 6 has high adhesive strength, is mechanically strong, has excellent moisture resistance and chemical resistance, has a high cut-through temperature, and has good heat resistance. An anti-corona coating is obtained.

[Phase] Note that the present invention is not limited to the embodiments described above and shown in the figure. For example, it is also possible to use Bribrae YP as the edge layer, or to use full impregnation insulation. It goes without saying that the present invention can be modified in various ways without changing the gist thereof.

As described above, according to the present invention, since the powder coating method is used, a corona prevention coating that does not generate resistive heat generation and prevents creeping discharge at the coil end is provided without impairing the original function of ground insulation in the coil. Can be manufactured. Since the coil is housed in the iron core and processed, a strong anti-corona coating can be obtained with simpler and cheaper work than in the past.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a sectional view showing the main parts of a common rotating electric machine provided with a corona prevention coating manufactured by a conventional method and an embodiment of the present invention. It is an explanatory view showing the state in the middle of manufacture in the manufacturing method of the corona prevention coating of the rotary electric machine of an example. l...Coil conductor, Co...Insulating layer, 3...Iron core, Da...φ
Slot, s @-low resistance coating a, g, fist corona prevention coating, t...powder, 9,10. /l...nozzle, /j...coil end. In each figure, the same reference numerals indicate the same or corresponding parts.
Agent Masuo Oiwa

Claims (1)

[Claims:] A method for manufacturing a corona prevention coating for a rotating electric machine in which an insulated stator coil is housed in an iron core. A low resistance coating of a conductive material is applied to the part of the stator coil that enters the iron core and a part near the end of the iron core and is placed in the iron core, overlapped with the low resistance coating that comes out of the iron core, and applied to the coil end K. Contains a bonding resin, contains a high dielectric constant filler such as barium titanate tS ~ qo% by weight, and after curing is 10-
1. A method for producing a corona prevention coating for a rotating electric machine, which comprises applying resin powder having a dielectric constant of 90 by a powder coating method to provide a high dielectric constant corona prevention coating.