JPH04112651A - Varnish impregnating method for electric machine - Google Patents

Abstract

PURPOSE:To impregnate even a narrow space with varnish effectively and to block flow out of varnish as low as posdible by covering a winding and a core with an airtight bag and impregnating the winding and the core with varnish contained in the bag while depressurizing the interior thereof. CONSTITUTION:A stator core 12 and a winding 13 are contained in an airtight bag 20 and predetermined amount of varnish is placed therein. Furthermore, a winding member 22 is fitted to the outer peripheral part of the coil end 13a. The mouth part 20a is then coupled with a pressure reducing unit which then performs evacuation and thermally sealed and finally decoupled. Since the interior of the bag is depressurized, the varnish 21 enters into narrow space such as the gap between the strands 15 or the gap between the winding 13 and a slot 12a. The stator core 12 and the winding 13 are then heated under that state thus curing the impregnated varnish. Since the varnish 21 cures while being contained in the bag 20, impregnated varnish does not flow out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method of impregnating electrical equipment with varnish, which is an improved method of varnishing a stator of a rotating electrical machine.

(Prior Art) In electrical equipment such as rotating electric machines, a stator core wrapped with windings is impregnated with varnish to improve insulation, heat resistance, and strength.

To describe this type of varnish impregnation method with reference to FIGS. 8 and 9, a stator 1 of a rotating electric machine is wound around a stator core 2 so as to be accommodated in an open slot 2a thereof. It is constructed by winding wire 3. When impregnating with varnish, the stator 1 is immersed in a container 5 containing varnish 4, as shown in FIG. After removal, the varnish 4 impregnated into the stator 1 is heated and hardened in a heating furnace.

(Problem to be Solved by the Invention) However, in the impregnation method as described above, it is difficult to impregnate the varnish 4 between the strands of the winding 3 or between the winding 3 and the slot 2a, and the excess varnish In the process of dropping 4, -
The varnish 4 that has been impregnated may sometimes flow out.

For this reason, as shown in FIG. 9, after the varnish 4 has hardened, a gap S is formed between the winding 3 and the slot 2a, resulting in poor insulation and mechanical strength of the winding 3. The problem arises that

In order to deal with this, a method of impregnating the varnish 4 in a vacuum container as shown in FIG. 8 has also been adopted. According to this, since the varnish 4 is impregnated in a reduced pressure state, the varnish 4 is impregnated into the dirt floor of the winding 3 as well as the narrow space between the winding 3 and the slot 2a. .

However, even with such a method of performing the impregnation work in a vacuum container, the impregnated varnish 4 flows out in the step of curing the varnish 4 after the impregnation work, and the void S
There was a problem that occurred.

The present invention has been made in view of the above circumstances, and its purpose is to provide an insulating layer with no voids, which can effectively impregnate a narrow space with varnish, and prevent the varnish from flowing out as much as possible. The purpose of the present invention is to provide a varnish impregnation method for electrical equipment that can form a varnish.

[Structure of the Invention] (Means for Solving the Problem) The method of impregnating electrical equipment with varnish of the present invention includes covering the winding wire and the iron core with an airtight bag, then reducing the pressure inside the bag, and applying the varnish in this reduced pressure state. The present invention is characterized in that the winding wire and the iron core are impregnated with the varnish in the bag.

(Function) According to the above method, since the varnish can be impregnated in a reduced pressure state, the varnish can be impregnated into the narrow space between the strands of the winding wire and between the winding wire and the iron core. Furthermore, since the varnish impregnation is performed while the windings and core are covered with an airtight bag, the varnish can be prevented from flowing out.

(Example) An example in which the present invention is applied to a varnish impregnation method for a stator of a rotating electric machine will be described below with reference to FIGS. 1 to 6.

First, the schematic structure of the stator 11, which is an electrical device, will be described with reference to FIGS. 4 to 6. This stator 11 is
It is constructed by winding a plurality of windings] 3 around a stator core 12. Among these, the stator core 2 is formed by laminating a plurality of thin steel plates, each having a ring shape and having a plurality of open slots 12a bored on the inner diameter side. Further, an insulator 14 is provided within this slot 12a. On the other hand, the winding] 3 is formed by winding a wire 15 such as an enameled wire, and a plurality of wires are housed in predetermined slots 12a and fixed by wedges 16, and are wound around the stator core 12. ing. Further, the coil end portion 13a that is not accommodated in the slot 12a is shaped by a binding thread 17, and the coil end portion 13a is shaped by a binding thread 17.
The necessary connections between the two are made and the sunrise line 18 (see FIGS. 1 and 2) is led out.

The stator 11 configured in this manner is impregnated with varnish as described later, and as a result, as shown in FIG. An insulating layer 9 made of varnish is formed between the material 14) and the like. This improves the heat resistance and vibration resistance of the winding 13, strengthens its adhesion to the stator core 12, and improves the insulation effect.

Now, the procedure for impregnating the stator core 12 and the winding 13 with varnish will be described with reference to FIGS. 1 to 3 as well.

First, the winding 13 is wound around the stator core 12 as described above. Then, this product is stored in an airtight bag 20. This airtight bag 20 is made of, for example, a flexible plastic film large enough to completely cover the stator 11, and as shown in FIG. An annular space capable of accommodating 11 is created. By accommodating the stator core 12 and the winding 13 in this space, their inner and outer peripheral portions are covered with the bag 20.

At this time, as shown in FIG. 2, a required amount of, for example, solvent-free varnish 21 is stored in the bag 20, and further, on the outer peripheral portion of the coil end portion 13a,
A ring-shaped wrapping of elastic material, for example urethane foam, engages the part 22.22. This winding is done by member 22.2.
2, the bag 20 is brought into close contact with the stator core 12 and the coil end portion 13a so as to substantially follow the outer peripheral shapes of the coil end portion 13a.

Thereafter, the opening 20a of the bag 20 is connected to a pressure reducing device (not shown) to evacuate the inside of the bag 20. As a result, as shown in FIG. 1, the inside of the bag 20 is depressurized and the stator core 12 and the winding 13 come into close contact with each other along the inner and outer peripheral shapes of the stator core 12 and the winding 13, so to speak. It will be in a vacuum backed state. In this state, the opening 2 of the bag 20
Heat seal 0a and disconnect from the pressure reducing device. At this time, since the varnish 21 is contained in the bag 20,
This varnish 21 is impregnated into the stator core 12 and the winding 13, but since the inside of the bag 20 is depressurized, the varnish 2j is impregnated! The strands 15 of 113 come to penetrate into the dirt floor and the narrow space between the winding 13 and the slot 12a.

Thereafter, the stator core 12 and the winding 13 are heated while still housed in the bag 20, and the varnish 2 impregnated with the stator core 12 and the winding 13 are heated.
1 is cured. This completes the stator 11 on which the varnish insulating layer 19 is formed. Furthermore, varnish 2
After curing 1, the bag 20 and wrapping member 22 are removed from the stator 11.

According to this embodiment, the varnish 21 can be effectively impregnated into the earthen floor of the wire 15 of the winding 13 and the narrow space between the winding 13 and the slot 12a. Moreover,
Since the varnish 21 is hardened while housed in the bag 20, the varnish 21 that has been impregnated will not flow out. Therefore, the winding 3 as described in the conventional example
Unlike the case where there is a possibility that a gap S may be formed between the insulating layer 19 and the slot 2a, an insulating layer 19 without a gap can be formed.
This makes it possible to sufficiently improve the heat resistance strength and vibration resistance of the winding 13, strengthen the adhesion to the stator core unit 2, and improve the insulation effect.

In particular, in this embodiment, the mouth 20a of the bag 20 is connected to a pressure reducing device to reduce the pressure inside the bag 20, so there is no need for a large-scale device such as a vacuum container that is required in the conventional method. , it can be done with extremely simple equipment and can be done at low cost.

In the above embodiment, the bag 20 is brought into close contact with the inner and outer peripheries of the stator 11 by folding back its lower part, but as shown in FIG. With the balloon-shaped inner diameter barrier 23 provided, the entire bag 24 may be housed in another bag 24, and the pressure between the inner diameter barrier 23 and the bag 24 may be reduced to impregnate the varnish.

Further, in the above embodiment, the required amount of varnish 21 is stored in the bag 20 in advance, but for example, a seat for varnish injection is formed in a part of the airtight bag, and after depressurization It is also possible to inject varnish into the material and impregnate it.

In addition to the method of directly connecting the mouth portion 20a of the bag 20 and a pressure reducing device to reduce the pressure inside the bag 20, for example, the bag 20 (the first one) in which the winding 13 and the iron core unit 2 are housed in a sealed container may be used. For example, a plurality of bags 20 (state shown in Fig. 2) are housed, and the inside of the sealed container is evacuated by a pressure reducing device to bring the inside of the plurality of bags 20 into a depressurized state at once.
It is also possible to consider a method in which the varnish 21 is injected into each portion after sealing the portions a.

Furthermore, the member 22 may not necessarily be provided for winding, and instead of the member 22 for winding, the stator 11 portion may be immersed in a water tank in the state shown in FIG. 2, for example.
The bag 20 may be made to follow the outer peripheral shape of the stator core 12 and the coil end portion 13H by water pressure.

In addition, the varnish is not limited to a thermosetting one, for example, an ultraviolet curable or anaerobic curable varnish may be used, and it can be applied not only to stators of rotating electrical machines but also to electrical equipment in general. The present invention can be implemented with various modifications without departing from the scope of the invention.

[Effects of the Invention] As is clear from the above explanation, according to the method of impregnating electrical equipment with varnish of the present invention, the winding and the iron core are covered with an airtight bag, and then the inside of the bag is depressurized. Since the varnish in the bag is impregnated into the winding wire and the iron core under reduced pressure, it is possible to effectively impregnate even a narrow space with the varnish, and to prevent the varnish from flowing out as much as possible, thereby preventing the varnish from flowing out. This has the excellent effect of making it possible to form an insulating layer with no oxidation.

[Brief explanation of drawings]

Figures 1 to 6 show an embodiment of the present invention, in which Figure 1 is a partially longitudinally sectional front view showing a state in which the inside of the bag containing the windings and core is depressurized, and Figure 2 3 is a perspective view of the bag, FIG. 4 is a perspective view of the stator, and FIG. FIG. 5 is an enlarged perspective view, and FIG. 5 is a partial cross-sectional view of the stator, and FIG. 7 is a longitudinal sectional front view showing another embodiment of the present invention in which the inside of the bag containing the windings and core is depressurized. It is. Furthermore, FIGS. 8 and 9 show a conventional example, and FIG. 8 is a vertical cross-sectional view schematically showing the state during varnish impregnation, and FIG. 9 is a partial cross-sectional view of the stator. . In the drawings,] 1 is a stator (electrical equipment), 12 is a stator core (iron core), 12a is a slot, 13 is a winding, 15 is a wire, 19 is an insulating layer, 20, 24 is a bag, and 21 is varnish. , 2 indicates the wrapping part and the rear part.

Claims (1)

[Claims] 1. An electric appliance characterized in that the winding wire and the iron core are covered with an airtight bag, and then the pressure inside the bag is reduced, and the varnish inside the bag is impregnated into the winding wire and the iron core in this reduced pressure state. How to impregnate equipment with varnish.