JPS6194531A - Armature winding for rotary electric machine - Google Patents

Abstract

PURPOSE:To suppress the corona discharge of insulating substance against earth, by using a corona shield formed by coating semi-conductive coat on one face of the film and fitting a collecting mica mat on the other face. CONSTITUTION:Corona shield layers 31 are formed by being provided with a semi-conductive coat layer 9 coated with semi-conductive coat on one face of a film 8 of approx. 0.025mm in thickness for example, and by being provided with a collecting mica mat layer 10 of approx. 0.1mm in thickness bonded on the other face of the film with the collecting mica mat and slight bonding agent. And the corona shield layers 31 are wound up on the whole outer periphery of a stator winding 4 so that the collecting mica mat layer 10 may be jointed to an insulating layer 2, and a stator winding 42 having the corona shield layers 31 is formed and is contained in the whole grooves 6 of a stator core 5. In this manner, the space between the the insulating layer and the corona shield layer is eliminated, and the corona discharge of insulating substance against earth can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an armature winding for a rotating electrical machine that prevents corona generation from grooves in the iron core of the rotating electrical machine.

[Technical background of the invention and its problems]

Conventionally, the armature winding of a rotating electrical machine, such as a stator winding, is constructed by winding mica tape around a conductor and applying an insulating layer impregnated with resin.

When the stator windings are housed in the grooves of the stator core in two stages, upper and lower, gaps are created between the corners of the stator windings at the portions where the upper and lower stator windings touch. Since this gap is large, the resin is not filled during the full impregnation process but flows out and remains even after the full impregnation process, causing corona to occur between the gap and the stator core and deteriorating the insulating layer.

In order to prevent this, low resistance (
A corona shield layer of 102 to 10"Ωan) is provided on the outer periphery of the insulating layer. That is, as shown in FIG.
First, a stator winding soil is formed, and a semiconductive paint is applied to the entire or part of the outer periphery of this insulating layer 2 using glass cloth, nonwoven fabric, film, etc. as a base material to form a sheet or tape. is wound to form a stator winding plate provided with a corona shield layer 3. Sheets and tapes made of crow cloth or non-woven fabric that form this corona shield layer 3 have poor flexibility and elongation, so they have poor adhesion to the insulating layer 2 and there is a fifth layer between the insulating layer 2 and the corona shield layer 3. A gap 7 as shown in the figure is generated. When this stator winding with the gap 7 is housed in the case 6 of the stator core 5 and used as a motor after being completely treated with impregnated resin, the stator core 5 and the corona shield layer 3 have the same potential, but Since a voltage is applied between the surface of the stator winding 1 and the corona shield layer 3, corona discharge occurs in the gap 7 and the insulating layer 2 deteriorates.

Further, when the corona shield layer 31'C film is used, it has superior flexibility and stretchability compared to glass cloth or nonwoven fabric, but has the following drawbacks.

(1) In the case of sheets or tapes with semiconductive paint coated on both sides of the film, cut the sheets or tapes to the required dimensions.
When r; Ir L/, the corona shield layer 3 is separated between both surfaces, and a part of the corona shield layer 3 is separated when it is wound around a coil.
becomes separated from the stator core 5, causing corona discharge.

(2) Even in the case of sheets or tapes coated with semiconductive paint on one side of the film, the adhesion is better than those using glass cloth or non-woven fabric, but if wrinkles occur or the stator Where the finished dimensions of the unwound insulating layer 2 are uneven, the adhesion deteriorates and the above-mentioned gap 7 is generated between the insulating layer 2 and the corona shield layer 3, causing corona discharge.

Therefore, in the final step, the entire stator winding is impregnated with varnish, resin, etc. to fill the gap between the insulating layer 2 and the corona shield layer 3. However, the following problems occur also in this process.

(1) When glass cloth or non-woven fabric is used, the varnish or resin used to treat the mesh will enter the mesh from both sides of the glass cloth or non-woven fabric (insulating layer side and anti-insulating layer side), causing the resistance value of the corona shield layer to be lower than the initial QI. X 10' to I X 10
'The corona shield layer does not have zero potential due to the increase in temperature, and the insulating layer and corona shield layer have a potential and corona discharge occurs in the gaps, so they do not function as a corona shield.

(2) When a film is used, the film surface is slippery, so the retention of varnish or resin is poor, and the varnish or resin that gets into the gap between the insulating layer and the corona shield layer flows out during the curing process and remains in the gap. remains in place.

In such a state, a sufficient corona shielding effect cannot be obtained, resulting in a shortened insulation life.

[Purpose of the invention]

The present invention improves the above-mentioned drawbacks, and aims to provide an armature winding for a rotating electrical machine having a corona shield layer that provides a sufficient corona shield effect.

[Summary of the invention]

The present invention relates to an armature winding of a rotating power embankment in which an insulating material is applied around a conductor, a corona shield is applied to the outer periphery, and the armature winding is housed in a groove of an iron core. A corona shield formed by coating a composite mica mat and pasting a composite mica mat on the other side is placed on the entire outer periphery or a part of the insulator so that the composite mica mat is on the insulator side, and is impregnated with a resin. This is an armature winding for a rotating electric machine characterized by the following. As a result, there is no gap between the insulator and the corona shield, and corona discharge between the insulator and the ground can be suppressed.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. However, the same parts as in the prior art will be designated by the same reference numerals and detailed explanation will be omitted. FIG. 1 is a longitudinal cross-sectional view of a stator winding housed in a groove in a stator core according to an embodiment of the present invention. A semi-conductive paint layer 9 coated with a conductive paint is provided, and a laminated mica mat layer 10 having a thickness of about 0.1 mm is provided on one side of the laminated mica mat layer 10, which is pasted with a small amount of adhesive. The resistance value of the semiconductive paint layer 9 varies depending on the position of the corona shield, but it is 10 to 10 Ω when used on the groove 6 portion of the stator core 5, and 10 to 10 Ω when used on the coil end portion. Make it about Ω-. The thickness of the semiconductive paint layer 9 is approximately 0.01 to 102 mm.

Then, with the mica mat layer 10 in contact with the insulating layer 2, the corona shield layer is wound around the entire outer circumference of the stator winding soil to form the stator winding protection provided by the corona shield layer. are stored in all 11h 6 of the stator core 5. Thereafter, the mica mat layer 10 and the gap between the mica mat layer 10 and the insulating layer 2 are impregnated with resin.

The corona shield layer U configured in this manner has good flexibility and elongation since the base material is the film 8 and the mica mat layer 10, so it can be easily wound tightly around the outer periphery of the insulating layer 2. Compared to 2, it has a cushioning effect and there are fewer gaps.

In addition, the mica mat layer 10 has good resin retention properties, and due to the resin impregnation treatment performed after the stator winding disc is housed in the groove 6 of the stator core 5, the number and amount of the mica mat layer 10 have been reduced compared to the past. The gap with the insulating layer 2 and the assembled mica mat layer 10 can be completely filled with the resin and become void-free. For this reason, the stator core 5, the corona shield return and the insulating layer 2 have the same potential, and the corona discharge that occurred in the conventional insulating layer 2, the corona shield return and the stator core 5 disappears. Deterioration of the insulating layer 2 is prevented.

Although the resin obtained by this resin impregnation treatment often penetrates into the assembled mica mat layer 10, a portion of the resin adheres to the semiconductive paint layer 9 with the film 8 as a boundary. However, since the stator core 5 and the semiconductive paint layer 9 are already in contact with each other before the resin impregnation treatment, the resistance value of the semiconductive paint layer 9 hardly increases due to the resin impregnation treatment and is fixed with the corona shield layer. It can maintain the same potential as the child core 5 and fully exhibits the effect of corona shielding.

An example of this effect is shown in FIG. 2, comparing the tan δ electric field characteristics between the conventional method and the present invention. As is clear from Fig. 2, as the electric field strength is increased, tan δ increases in the conventional case, but the change in tan δ in the present invention is small, indicating that the present invention has better discharge suppression than the conventional one. I understand. As a result, the scattering suppression effect has been greatly improved, and the life of the current applied life characteristics is also significantly improved compared to conventional armature winding insulation.

In the above embodiment, a corona shield return is provided in each of the upper and lower stator winding discs which are housed in the box 6 of the stator core 5. As shown, with the stator windings with the insulating layer 2 on the outer periphery stacked in two stages, the stator winding board with the corona shield return arranged in the same manner as described above is attached to the stator core from the outer periphery. 5 and impregnated with resin, the same effect as in the above embodiment can be obtained.

In addition, by arranging the two types of stator winding discs and coronas separately in the grooves of the core having tact in the axial direction, it is possible to prevent corona discharge between the stator winding discs and the core in the duct section. It has a suppressing effect.

Further, the above embodiment can be used not only for rotating electric machines of 6 kV class or higher, but also for low voltage machines of 6 kV class or lower. It may also be used for the corona shielding effect of rotor windings.

〔Effect of the invention〕

As described above, according to the present invention, a corona shield layer formed by providing a composite mica mat layer and a semi-conductive paint layer on both sides of the film, and an armature winding formed by providing a composite mica mat layer and an insulating layer on both sides of the film. By storing the wire in the groove of the iron core of the rotating electric machine, there is no gap between the insulating layer and the corona shield layer, and corona discharge between the insulator and the ground can be suppressed.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a 74i according to an embodiment of the present invention, with the machine windings housed in the grooves of the iron core, and Fig. 2 is a longitudinal cross-sectional view of a 74i according to an embodiment of the present invention.
Figure 3 is a longitudinal sectional view showing another embodiment of the present invention; Figure 4 is a longitudinal sectional view showing a conventional armature winding housed in the groove of the iron core; Figure 5 is a longitudinal sectional view showing another embodiment of the present invention; It is an enlarged view of the part enclosed by the dashed-dotted line of a figure. 1... Conductor, 2... Insulating layer. Earth, 41.42.43...Stator winding. 6...Groove, 8...Film. 9... Semi-conductive paint layer, 10... Laminated mica mat layer. Sleeping...Corona shield layer. Agent Patent attorney Kensuke Chika (and 1 other person) $'?
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Claims (1)

[Claims] In the armature winding of a rotating electric machine, in which an insulating material is applied around the conductor, a corona shield is applied to the outer periphery, and the armature winding is housed in a groove in the iron core, one side of the film is coated with a semiconductive paint and the other side is coated with a semiconductive paint. A corona shield formed by pasting a composite mica mat on the insulator is disposed on the entire outer periphery or a part of the insulator so that the composite mica mat is on the insulator side, and is impregnated with a resin. Armature winding of electrical machinery.