JPH07308038A - Water-cooled stator coil end structure for electric rotating machine - Google Patents

Abstract

PURPOSE:To facilitate the confirmation of water leak from a brazed part and to take a countermeasure easily. CONSTITUTION:Cooling water is fed through the inside of a plurality of coil strands 15 constituting a water-cooled stator coil and the plurality of coil strands 15 are inserted into a clip 11 and brazed. In such stator coil end structure, an air gap 19 is provided contiguously to the brazed part between the clip 11 and the plurality of coil strands 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water cooling stator coil end structure of a rotary electric machine, and in particular, it is possible to confirm water leakage from a brazing portion of the stator coil end and take preventive measures against it. The present invention relates to a water cooling stator coil end structure of a rotating electric machine.

[0002]

2. Description of the Related Art In a large-capacity rotating electric machine, cooling water is passed through the strands of the stator coil in order to increase the current flowing in the stator coil and to suppress the temperature rise even if the current density increases. The so-called stator coil water cooling system is used for replacement.

Further, the stator coil needs to form a complicated armature winding in order to obtain a three-phase AC power source such as a turbine generator. The stator coil must be housed in the stator core slot, electrically connected to the coil housed in another slot at the end portion, and a water passage for cooling water must be formed. Due to manufacturing technology, this cooling water passage is integrated with the electrical connection,
A hollow clip is provided at the end of the stator coil.

This clip is connected to a stator coil consisting of a plurality of hollow wires by brazing, and the wires and clips are electrically connected, except for a turbine generator of a large-capacity rotating electric machine. As described above, it is necessary to perform gas sealing for the device in which hydrogen gas is pressurized and sealed in the machine.

As described above, the gap between the plurality of hollow wires and the clip is minimized under precise dimensional control, and the gap is filled with a brazing material for electrical connection and hydrogen gas sealing.

However, the plurality of wires are hollow, and closing the hollow portion is not allowed in terms of the water-passing function, and brazing between the wires and the clips is the minimum necessary brazing. Depending on the material, all the brazing must be adhered between each strand, which requires a high degree of skill.

The structure of the stator water cooling turbine generator and the stator coil end connection structure will be described below with reference to FIGS. FIG. 5 shows a cross section of the turbine generator, in which hydrogen gas is enclosed, and a spring plate (not shown) is inserted in the stator frame 1 for elastically supporting the ribs 2, and the stator core 3 is attached to the ribs 2. Are stacked. Further, a plurality of slot grooves are formed on the inner diameter side of the stator core 3, the lower coil 7 and the upper coil 8 of the stator coil are housed in the slot grooves, and these are fixed by a stator wedge (not shown). .

On the other hand, the rotor 4 is supported by the bearing metal 5, and the stator frame 1 is supported by the bearing bracket 6.
Supported at the end of. The lower coil 7 and the upper coil 8 housed in the slot groove of the stator iron core 3 are supported by the bind strip support 9 at the end portion outside the iron core, and the series connection portion is formed to form an electric circuit at the coil end portion. Connected at 10.

Clips 11 are provided at the respective ends of the lower coil 7 and the upper coil 8, and cooling water is supplied from a stator cooling pure water device (not shown) to a water supply header 13 through a water supply pipe 12. Water is passed through each clip 11 through the insulating connecting pipe 14. As shown in FIG. 6, the hollow coil wire 15 of the stator coil has a hollow hole,
Cooling water is passed through these holes for heat exchange.

The clip 11 is formed in a hollow shape, and the open end of the clip 11 is fitted with a plurality of coil wires 15 having hollow holes which form the lower coil 7 and the upper coil 8. As shown in FIG. In the brazing area A, the wires 15 and the inside of the clip 11 are brazed. This brazing is for electrically connecting the wires 15 and for preventing the cooling water in the clip 11 from leaking to the outside. In FIG. 7, 16 is a coil insulating layer and 17 is an end insulating layer.

[0011]

By the way, the inside of the clip 11 shown in FIGS. 6 and 7 is hollow,
The coil wire 15 is inserted and fitted from the opening side at one end and brazing is performed. However, since the hollow hole at the end of the coil wire 15 opens into the clip inner water chamber 18, the hollow hole between the coil wires 15 is formed. It is necessary to braze so that it does not block, and a large amount of brazing material cannot be used. In addition, since brazing cannot be performed from the insertion side of the coil wire 15 in order to perform brazing in which brazing material is added later, advanced technology is required for pouring the brazing material completely and sufficiently between the coil wires 15. It

If there is a lack of brazing material or a blow hole communicating with the inside of the clip 11, the brazing material will be corroded and eroded due to galvanic corrosion (contact corrosion of dissimilar metals) over the years, and the opening end side of the clip 11 will be exposed. There is a risk of communication. And since the cooling water has a predetermined pressure,
When passing through the coil wire 15 outside the clip 11 and penetrating into the coil insulating layer 16 and performing a withstand voltage test, there is a possibility of causing dielectric breakdown. The speed at which the cooling water leaks and the period until dielectric breakdown are important for evaluating the remaining life.
There is an urgent need here to discover and take measures early.

In the case of a turbine generator, since the pressure of the cooling water is lower than the pressure of the hydrogen gas inside the machine, the leakage of water from the stator coil does not leak into the machine and the hydrogen gas leaks into the cooling water system. .

Therefore, the first judgment is made by measuring the hydrogen gas concentration in the water storage tank arranged in the device for circulating the cooling water in the cooling water system. Then, after opening the generator, the water leakage site will be identified by detailed inspection. However, since the stator coil is insulated, it is difficult and very time consuming to identify the leakage site.

Further, when repairing after the leaked portion is specified, it is possible by re-brazing, but brazing between the coil end clip and the coil wire is overheated during brazing repair as shown in FIG. Re-brazing is not possible because it damages the insulation.

The present invention has been made in consideration of the above-mentioned circumstances, and water leakage from the brazing portion can be easily confirmed, and water leakage prevention measures of the rotating electric machine can be easily implemented. It is intended to provide a partial structure.

[0017]

In order to solve the above-mentioned problems, the first aspect of the present invention is that the cooling water is passed through the inside of a plurality of coil wires constituting the water cooling stator coil to generate heat. In the water-cooled stator coil end structure of the rotating electric machine in which the plurality of coil wires are exchanged and brazed by inserting them into the hollow clip, in the brazing portion between the clip and the plurality of coil wires. It is characterized in that a void chamber is provided adjacently.

A second aspect of the present invention is characterized in that the void chamber according to the first aspect communicates with the outside through an insulating tube, and accommodates a hygroscopic material whose color changes when cooling water permeates into the insulating tube.

According to a third aspect of the present invention, the void chamber according to the first or second aspect is formed by a rectangular conductive cover having openings on both sides, one end of the conductive cover is brazed to a clip, and the other end is plural. It is characterized in that it is brazed so as to wrap the coil wire of the book.

According to a fourth aspect of the present invention, the void chamber is formed by a rectangular insulating cover whose both sides are open. One end of this insulating cover is brazed to a clip and the other end is inserted with a plurality of coil element wires. It is characterized in that a lattice-shaped seal plate is fitted.

A fifth aspect of the present invention is characterized in that, when water leakage occurs in the void chamber according to any one of claims 1, 2, 3 or 4, an permeable insulating resin is pressed into the void chamber from an insulating tube.

[0022]

According to the first aspect of the present invention, since the void chamber is provided adjacent to the brazing portion between the clip and the plurality of coil element wires, the inside of the clip and the void chamber are corroded by corrosion or erosion of the brazing material. In the case of communication between the air gap and the air gap, water pressure leaks into the air gap chamber because the cooling water pressure in the clip is higher than that in the air gap chamber. As a result, it is possible to easily confirm the water leak and easily take measures for preventing the water leak.

According to a second aspect of the present invention, the void chamber according to the first aspect communicates with the outside through an insulating tube, and a moisture absorbent that changes color when cooling water permeates is contained in the insulating tube, thereby preventing water leakage. It can be easily confirmed visually.

According to a third aspect of the present invention, the void chamber according to the first or second aspect is formed by a rectangular conductive cover having openings on both sides, and one end of the conductive cover is brazed to a clip and the other end is brazed. By brazing so as to wrap a plurality of coil element wires, the void chamber can be formed reliably and easily.

According to a fourth aspect of the present invention, the cavity is formed by a rectangular insulating cover whose both sides are open. One end of this insulating cover is brazed to a clip, and the other end is inserted with a plurality of coil element wires. By fitting the lattice-shaped seal plate, which does not require high technology, it is possible to seal each coil wire thoroughly.

According to a fifth aspect of the present invention, when a water leak occurs in the void chamber according to the first, second, third or fourth aspect, the permeable insulating resin is press-fitted into the void chamber from an insulating tube to thereby cause a water leak path. Can be filled.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a partial sectional view showing an embodiment of a water cooling stator coil end structure of a rotating electric machine according to the present invention, FIG. 2 is an exploded perspective view showing a clip and a conductive cover of FIG. 1, and FIG. 3 is a cross-sectional view showing the insulating tube of FIG. The same or corresponding portions as those of the conventional configuration will be described using the same reference numerals, and since the overall configuration is substantially the same as the coil end structure shown in FIG. 7, description thereof will be omitted.

As shown in FIG. 1, the coil wires 15 arranged in a plurality of stages are covered with a conductive cover 20 formed in a rectangular shape with both sides open, and one end of this conductive cover 20 is clip 11. Since the other end is brazed so as to wrap the plurality of coil wires 15, the void chamber 19 is formed in the fitting peripheral surface of the coil wire 15 of the clip 11. That is, the void chamber 19 is formed adjacent to the brazing portion between the clip 11 and the plurality of coil element wires 15. In this case, butt brazing may be performed on the clip 11 side. It is desirable to apply, for example, magnesium hydroxide to the coil wire 15 in the void chamber 19 so that the brazing material does not flow into it.

As shown in FIG. 2, the conductive cover 20 is provided with two tube insertion holes 22 in which upper and lower female threads for inserting and fixing the insulating tube 21 are formed.
An insulating tube 21 is attached to each of the tube insertion holes 22 so that the void chamber 19 communicates with the outside via the conductive cover 20 and the coil insulating layer 16. In this case, the insulating tube 21 is inserted into the tube insertion hole 22.

Further, as shown in FIG. 3, the insulating tube 21 has male threads engraved on both ends thereof, and the coil insulating layer 16
A cap 25 made of an insulating material is detachably attached to the end of the insulating tube 21 exposed to the outside. Also,
A hygroscopic material 26 such as silica gel or activated alumina, which changes color when absorbing moisture, is housed in the insulating tube 21.

Next, the operation of this embodiment will be described.
When the brazing filler metal between the coil wires 15 and the inner surface of the clip 11 is corroded and eroded by galvanic corrosion over time and penetrates between the clip inner water chamber 18 and the void chamber 19, the clip inner water Since the pressure of the cooling water in the chamber 18 is higher than that in the void chamber 19, water leakage occurs on the void chamber 19 side. In this case, the presence or absence of water leakage can be visually confirmed by removing the cap 25 and inspecting it, and if the moisture absorbing material 26 is removed, a detailed inspection of the inside of the void chamber 19 can be performed. Will also be possible.

When water leakage is recognized, the insulating tube 2 exposed to the outside of the coil insulating layer 16 as a countermeasure.
The inside of the void chamber 19 is evacuated from 1 and the insulating resin is injected, so that the water leak path can be filled and the periphery of the void chamber 19 can be further reinforced by impregnating the stator coil with the insulating resin.

As described above, according to this embodiment, the clip 1
When the void chamber 19 is provided adjacent to the brazing portion between the one and the plurality of coil wires 15, when the inside of the clip 11 and the void chamber 19 are communicated with each other by corrosion and erosion of the brazing material,
Since the cooling water pressure in the clip 11 is higher than that in the void chamber 19, water leaks into the void chamber 19. As a result, it is possible to easily confirm the water leak and easily take measures for preventing the water leak.

In addition, since the hygroscopic material 26 whose color changes when the cooling water permeates into the insulating tube 21 is housed,
Water leakage can be easily confirmed visually. Further, the void chamber 19 is formed by a rectangular conductive cover 20 having openings on both sides, one end of the conductive cover 20 is brazed to the clip 11, and the other end wraps a plurality of coil wires 15. By brazing, the void chamber 1
9 can be formed reliably and easily.

FIG. 4 is an exploded perspective view showing a clip and a cover according to another embodiment of the present invention. In this embodiment, an insulating cover 23 is provided in place of the conductive cover 20 of the previous embodiment, and one end of this insulating cover 23 has the clip 11
Seal plate 2 brazed to the other end and formed in a grid pattern at the other end
4 is fitted, and a plurality of coil wires 15 are inserted into the void portion of the seal plate 24, whereby a void chamber is formed on the fitting peripheral surface of the coil wire 15 of the clip 11.

Therefore, according to this embodiment, the sealing plate 24 is fitted to the other end of the insulating cover 23, and the plurality of coil wires 15 are inserted into the sealing plate 24, which requires a high level of technology. Therefore, the coil wires 15 can be completely sealed. The other structure and operation are the same as those of the above-mentioned embodiment, and the explanation thereof is omitted.

[0037]

As described above, according to the first aspect of the present invention.
According to the above, by providing the void chamber adjacent to the brazing portion between the clip and the plurality of coil wires, when the brazing filler metal is corroded and corroded by erosion, Since the cooling water pressure in the clip is higher than that of the void chamber,
Water leaks into the void chamber. As a result, water leakage can be easily confirmed, water leakage prevention measures can be easily taken, deterioration of the coil insulation can be prevented, and the life of the stator coil can be extended.

According to the second aspect, the water leakage due to the fact that the void chamber according to the first aspect communicates with the outside through the insulating tube and the hygroscopic material whose color changes when the cooling water permeates into the insulating tube is stored. Can be easily checked visually and the construction period for inspection can be shortened.

According to a third aspect of the present invention, the void chamber according to the first or second aspect is formed by a rectangular conductive cover whose both sides are open, and one end of this conductive cover is brazed to a clip and the other end. By brazing so as to wrap a plurality of coil wires, the void chamber can be formed reliably and easily.

According to the fourth aspect, the void chamber is formed by a rectangular insulating cover whose both sides are open. One end of this insulating cover is brazed to the clip, and the other end is provided with a plurality of coil wires. By fitting the lattice-shaped seal plate to be inserted, it is possible to seal each coil wire thoroughly without requiring high technology.

According to the fifth aspect, when water leakage occurs in the void chamber according to any one of claims 1, 2, 3 or 4, the permeable insulating resin is press-fitted into the void chamber from the insulating tube to cause water leakage. The road can be filled, and the reliability of the rotating electric machine can be improved.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of a water cooling stator coil end structure of a rotating electric machine according to the present invention.

FIG. 2 is an exploded perspective view showing the clip and the conductive cover of FIG.

FIG. 3 is a sectional view showing the insulating tube of FIG.

FIG. 4 is an exploded perspective view showing a clip and a cover according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a conventional stator coil water cooling turbine generator.

FIG. 6 is a perspective view showing a clip portion of a conventional stator coil end portion.

FIG. 7 is a partial cross-sectional view showing a structure of a series connection portion of a conventional stator coil end portion.

[Explanation of symbols]

 7 Lower Coil 8 Upper Coil 10 Series Connection 11 Clip 15 Coil Element 16 Coil Insulation Layer 19 Cavity 20 Conductive Cover 21 Insulation Tube 22 Tube Insertion Hole 23 Insulation Cover 24 Seal Plate 25 Cap 26 Moisture Absorber

Claims (5)

[Claims] 1. Cooling water is passed through the inside of a plurality of coil element wires constituting a water-cooled stator coil to exchange heat, and the plurality of coil element wires are inserted into a hollow clip to be brazed. In a water cooling stator coil end structure for a rotating electric machine, a water cooling stator coil for a rotating electric machine is characterized in that a void chamber is provided adjacent to a brazing portion between the clip and a plurality of coil wires. Edge structure. 2. The water for a rotary electric machine according to claim 1, wherein the void chamber communicates with the outside through an insulating tube, and contains a hygroscopic material whose color changes when the cooling water permeates into the insulating tube. Cooling stator coil end structure. 3. The void chamber is formed by a rectangular conductive cover having openings on both sides, one end of this conductive cover is brazed to a clip, and the other end is wrapped with a plurality of coil wires. The water-cooled stator coil end structure for a rotating electric machine according to claim 1 or 2, wherein the water-cooled stator coil end structure is attached. 4. The void chamber is formed by a rectangular insulating cover having openings on both sides, one end of this insulating cover is brazed to a clip, and the other end is formed in a lattice shape in which a plurality of coil wires are inserted. 3. A water cooling stator coil end structure for a rotating electric machine according to claim 1, wherein a seal plate is fitted. 5. The water for a rotary electric machine according to claim 1, 2, 3 or 4, wherein when water leakage occurs in the void chamber, an permeable insulating resin is pressed into the void chamber from an insulating tube. Cooling stator coil end structure.