Method for manufacturing stator coil, stator coil, and rotary machine

Abstract

This method for manufacturing a stator coil comprises: a first step for winding a mica tape (7) on a coil conductor (5); a second step for winding a prepreg tape (9) on the coil conductor (5) on which the mica tape (7) has been wound; a third step for winding a thermal shrinkage tape on the outer circumference of the coil conductor (5) on which the mica tape (7) and the prepreg tape (9) have been wound; a fourth step for heating the coil conductor (5) and curing a resin included in the prepreg tape while compressing the mica tape (7) and the prepreg tape (9) by a shrinking force of the thermal shrinkage tape (8); a fifth step for removing the thermal shrinkage tape (8) and impregnating the mica tape (7) with a liquid resin (10); and a sixth step for heating the coil conductor (5) and curing the liquid resin (10). By using said method, a stator coil having excellent electricity resistance and heat dissipation ability can be provided.

Description

Stator coil manufacturing method, stator coil and rotating machine

[0001] The present disclosure relates to a method for manufacturing a stator coil, and a stator coil and a rotating machine using the same.

[0002] Large, high-voltage rotating machines used in turbine generators and industrial motors are made up of coil insulation material around the inner periphery of the stator core. In recent years, there has been an increasing demand for smaller and higher-power rotating machines, and to achieve this, coil insulation materials are required to have high voltage resistance as well as high heat dissipation properties to efficiently transfer heat generated by the coil conductor to the core.

[0003] Common methods for producing coil insulating materials include the vacuum impregnation method, in which a mica tape, consisting of a mica sheet laminated with a fiber reinforcement material such as glass cloth, is wrapped around a coil conductor several times, impregnated with a low-viscosity liquid curable resin composition (hereinafter referred to as liquid resin) under reduced pressure, and then heated to harden. The resin-rich method, in which a semi-cured resin is applied to an insulating tape, and the resulting tape is then wrapped around a coil conductor and hot-pressed. Among these methods, the vacuum impregnation method is suitable for producing large, high-voltage rotating machines that are expected to operate for long periods of time, because it is less likely to develop voids that could lead to insulation defects within the coil insulating material. Furthermore, in the vacuum impregnation method, prior to the heating step, the coil wrapped with the mica tape containing the liquid resin is placed in a mold and compressed under pressure, allowing excess liquid resin impregnated in the mica tape to be expelled from the coil ends. Heating the coil in this state to harden the liquid resin increases the mica content in the coil insulating material, thereby improving voltage resistance.

[0004] However, with this method, when the liquid resin is heated and hardened, the liquid resin is heated before the hardening reaction begins, causing its viscosity to temporarily decrease, causing it to leak out through the gaps in the mica tape and creating voids on the surface of the coil insulation material that can become insulation defects.

[0005] In response to this, Patent Document 1 describes a method in which mica tape is wound to a predetermined thickness around the surface of a coil conductor to form a main insulating substrate layer, a finishing tape made by bonding heat-shrinkable cloth tape and heat-shrinkable film tape is wound around the outside of the main insulating substrate layer in the coil end portion, and then vacuum impregnation with resin and heat treatment are performed. By performing vacuum impregnation with resin and heat treatment on the coil insulating material using the manufacturing method described in Patent Document 1, the finishing tape heat shrinks during the resin heat-hardening treatment, making it possible to prevent resin leakage in the coil end portion, suppress the generation of voids in the coil insulating material, and improve voltage resistance.

[0006] Japanese Patent Application Publication No. 5-30695

[0007] However, in this method, which involves wrapping mica tape around the coil conductor and wrapping finishing tape around it, followed by vacuum resin impregnation and heat treatment, the liquid resin between the mica tapes is not fully discharged, which means the mica tape cannot be fully compressed, resulting in a low mica content in the coil insulation material and a decrease in electrical resistance. Furthermore, there are issues with the amount of resin with low thermal conductivity, which can lead to a decrease in the heat dissipation performance of the coil.

[0008] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a method for manufacturing a stator coil that can improve voltage resistance and heat dissipation.

[0009] The method for manufacturing a stator coil according to the present disclosure includes a first step of winding mica tape around a coil conductor formed by winding a conductor into a coil shape; a second step of winding prepreg tape around the coil conductor around which the mica tape is wound; a third step of winding heat-shrinkable tape around the outer periphery of the coil conductor around which the mica tape and prepreg tape are wound; a fourth step of heating the coil conductor and curing the resin contained in the prepreg tape while compressing the mica tape and prepreg tape with the contraction force of the heat-shrinkable tape; a fifth step of removing the heat-shrinkable tape and impregnating the mica tape with liquid resin; and a sixth step of heating the coil conductor and curing the liquid resin.

[0010] The stator coil according to the present disclosure includes a coil conductor, a first insulating layer containing mica tape and hardened liquid resin around the outer periphery of the coil conductor, and a second insulating layer in which prepreg tape is wound around the outer periphery of the first insulating layer without overlapping, and the resin contained in the prepreg tape is hardened.

[0011] According to the method for manufacturing a stator coil according to the present disclosure, the mica tape and prepreg tape are compressed with heat-shrinkable tape before the mica tape is impregnated with liquid resin, and the resin contained in the prepreg tape is hardened to maintain the compressed state, thereby preventing excess liquid resin from being contained between the mica tapes and enabling the voltage resistance and heat dissipation of the stator coil to be improved.

[0012] FIG. 1 is a perspective view showing a schematic configuration of a stator of a rotating machine according to a first embodiment of the present disclosure. FIG. 2 is a front view showing a schematic configuration of a coil end portion of a stator coil according to a first embodiment of the present disclosure. FIG. 3 is a flowchart showing each step of a method for manufacturing a stator coil according to a first embodiment of the present disclosure. FIG. 4 is a cross-sectional view showing a coil conductor in a first step of the method for manufacturing a stator coil according to a first embodiment of the present disclosure. FIG. 5 is a cross-sectional view showing a coil conductor in a second step of the method for manufacturing a stator coil according to a first embodiment of the present disclosure. FIG. 6 is a cross-sectional view showing a coil conductor in a third step of the method for manufacturing a stator coil according to a first embodiment of the present disclosure. FIG. 7 is a cross-sectional view showing a coil conductor in a fourth step of the method for manufacturing a stator coil according to a first embodiment of the present disclosure. FIG. 8 is a cross-sectional view showing a coil conductor in a fifth step and a sixth step of the method for manufacturing a stator coil according to a first embodiment of the present disclosure.

[0013] First Embodiment. Fig. 1 is a perspective view showing a schematic configuration of a stator of a rotating machine according to a first embodiment of the present disclosure. As shown in Fig. 1, the stator of the rotating machine has two stages of stator coils 3 housed inside slots 2 of a stator core 1. A spacer (not shown) is inserted between the two stages of stator coils 3, and wedges 4 for fixing the stator coils 3 are disposed at the open ends of the slots 2. The wedges 4 suppress vibrations due to electromagnetic forces generated from the stator coils 3 during operation of the rotating machine. Here, an example is shown in which two stages of stator coils 3 are housed inside slots 2 of the stator core 1, but the number of stator coils 3 housed in the slots 2 is not limited in the present disclosure.

[0014] FIG. 2 is a front view showing a schematic configuration of a coil end portion of a stator coil according to the first embodiment of the present disclosure. As shown in FIG. 2 , the coil end portion has a curved coil conductor 5, which is the conductor portion of the stator coil 3. The coil conductor 5 may be, for example, a bundle of flat metal wires. The coil conductor 5 is covered with a coil insulating material 6, which provides ground insulation with the stator core. The coil insulating material 6 is formed from mica tape, prepreg tape, and a liquid resin impregnated into the mica tape. Here, in the present embodiment, a flat metal wire is used as an example of the cross-sectional shape of the coil conductor 5, but the cross-sectional shape of the coil conductor may also be circular, etc.

[0015] FIG. 3 is a flowchart showing the steps of a method for manufacturing a stator coil according to the first embodiment of the present disclosure. As shown in FIG. 3 , the method for manufacturing a stator coil includes steps S1 to S6. Step S1 is a first step of winding mica tape 7 around the coil conductor 5. Step S2 is a second step of winding prepreg tape 9 around the coil conductor 5 around which the mica tape 7 has been wound. Step S3 is a third step of winding heat-shrinkable tape 8 around the coil conductor 5 around which the mica tape 7 and prepreg tape 9 have been wound. Step S4 is a fourth step of heating the coil conductor 5 and compressing the mica tape 7 and prepreg tape 9 with the contraction force of the heat-shrinkable tape 8, thereby curing the resin contained in the prepreg tape 9. Step S5 is a fifth step of removing the heat-shrinkable tape 8 and impregnating the mica tape 7 with liquid resin 10. Step S6 is a sixth step of heating the coil conductor 5 and curing the liquid resin 10.

[0016] FIG. 4 is a cross-sectional view showing a coil conductor in a first step of the manufacturing method of the stator coil according to the first embodiment of the present disclosure. In the first step, mica tape 7 is wrapped around the coil conductor 5 multiple times in a semi-lap winding. The mica tape 7 used in the present disclosure has a structure in which mica and a reinforcing material such as glass cloth or a resin film are bonded with epoxy resin or silicone resin. When wrapping the mica tape 7 around the coil conductor 5, the mica layer of the mica tape 7 is wound on the coil conductor 5 side. However, to improve resin impregnation, a separate resin flow layer such as glass cloth may be provided on the mica layer side to improve resin impregnation. Because the innermost layer of the mica tape tends to be difficult to impregnate with resin, it is possible to improve impregnation by wrapping it with, for example, glass cloth on the conductor side.

[0017] Furthermore, when winding the mica tape 7 around the coil conductor 5, it is desirable to apply tension to the mica tape 7 to prevent wrinkles from forming. If wrinkles form, the mica may break, causing the mica to become misoriented and reducing voltage resistance. Methods for effectively preventing wrinkles from forming include, when winding the mica tape 7 while applying tension to it, preheating the coil conductor 5 and the mica tape 7 to increase the flexibility of the mica tape 7 beforehand, and storing the mica tape 7 in a humid atmosphere before using it.

[0018] 5 is a cross-sectional view showing the coil conductor in the second step of the manufacturing method of the stator coil according to the first embodiment of the present disclosure. In the second step, a prepreg tape 9, which uses mica as a tape substrate, is wound around the outer periphery of the coil conductor 5 around which the mica tape 7 is wound. Here, the prepreg tape 9 used in the present disclosure is a tape containing a semi-cured thermosetting resin. For example, glass cloth, mica, film, nonwoven fabric, insulating paper, cloth substrate, etc. can be used as the tape substrate. However, glass cloth and mica have high mechanical strength and are therefore suitable for the prepreg tape 9 of the present disclosure. When increasing the voltage resistance with the prepreg tape 9, as in the present disclosure, it is desirable to use mica.

[0019] The prepreg tape 9 is 1 m long from the viewpoint of voltage resistance. ２ The mica mass per unit is 30 to 100 g / m ２ From the viewpoint of ease of winding, the thickness is preferably in the range of 0.1 mm to 2 mm. In the present disclosure, the semi-cured thermosetting resin may be an epoxy resin, a silicone resin, a phenolic resin, or a polyester resin, and epoxy resin in particular has excellent adhesiveness to the mica tape 7.

[0020] The semi-cured thermosetting resin cures upon heating, and after curing, it is necessary for its elastic modulus to increase and for it to have insulating properties. Furthermore, the curing initiation temperature of the thermosetting resin is preferably higher than the shrinkage initiation temperature of the heat-shrinkable tape 8 of the present disclosure. The curing initiation temperature of the thermosetting resin can be measured by DSC (differential scanning calorimetry) and can be defined as the peak initiation temperature of the exothermic reaction accompanying the curing reaction. The curing initiation reaction can be adjusted by the curing catalyst contained in the prepreg tape 9. When an epoxy resin is used, examples of the curing catalyst that can be used include aromatic polyamines, aliphatic polyamines, imidazole derivatives, and tertiary amine salts. Furthermore, the thermosetting resin may be combined with a metal soap composed of a metal bond and a long-chain fatty acid to adjust the curing initiation time.

[0021] As with mica tape 7, the prepreg tape 9 can be wound multiple times in a semi-overlap winding in the tape width direction, or wound without overlapping in the tape width direction. When the prepreg tape 9 is wound multiple times in a semi-overlap winding in the tape width direction, the prepreg tape overlaps in two layers, resulting in a thicker tape. This increases the mechanical strength of the prepreg tape 9 after it hardens. However, in the fifth step of the present disclosure, if the prepreg tape 9 overlaps in the coil cross-section direction, the overlapping portions are less likely to be impregnated with the liquid resin. If voids are present in the overlapping portions, insulation defects may occur. To prevent these insulation defects, it is desirable to provide multiple holes in the prepreg tape 9 in advance to serve as resin impregnation channels.

[0022] Furthermore, when the prepreg tape 9 is wound so that it does not overlap in the tape width direction, the prepreg tape 9 becomes a single layer. In this case, since the prepreg tape 9 does not overlap, there is an advantage that it is easy to impregnate with the liquid resin 10. As a result, voids that cause insulation defects do not occur in the coil insulating material 6, improving the voltage resistance. The mechanical strength of the prepreg tape 9 after curing is lower than when it is wound so that it overlaps in the tape width direction, but by using mica or glass cloth as the base material of the prepreg tape 9, it is possible to impart the mechanical strength necessary for practical use.

[0023] In the second step, too, it is desirable to apply tension to the prepreg tape 9 while winding it to prevent wrinkles from forming. If the thickness of the prepreg tape is less than 0.1 mm, the tape will deform when tension is applied during winding, making it more likely to break. Furthermore, if the thickness of the prepreg tape 9 exceeds 0.3 mm, it will be difficult to wind the tape along the outer periphery of the mica tape 7, making it more likely to cause wrinkles from winding. Therefore, the thickness of the prepreg tape 9 is preferably 0.1 mm or more and 0.3 mm or less to make winding easier.

[0024] If the amount of resin contained in the prepreg tape 9 is less than 20 g, the prepreg tape 9 will have low mechanical strength after curing and will be prone to deformation. If the amount of resin exceeds 200 g, the resin in the prepreg tape 9 will flow out into the mica tape 7 and harden when the prepreg tape 9 is cured in the fourth step while the shrinkage force of the heat-shrinkable tape 8 is being generated. This may result in a decrease in the content of the resin impregnated in the fifth step. Therefore, the amount of resin contained in the prepreg tape 9 is set to 100 g per meter of tape in order to obtain the mechanical strength of the prepreg tape 9 after curing. ２ It is preferable that the weight is 20 g or more and 200 g or less per unit.

[0025] 6 is a cross-sectional view showing the coil conductor in the third step of the manufacturing method of the stator coil according to the first embodiment of the present disclosure. In the third step, heat-shrinkable tape 8 is wound around the outer periphery of the coil conductor 5, which is wrapped with mica tape 7 and prepreg tape 9. The heat-shrinkable tape 8 is wound so that it can be removed before the fifth step is performed. In addition, by placing a plate-shaped backing plate around the outer periphery of the prepreg tape 9, the surface of the prepreg tape 9 can be smoothed when the heat-shrinkable tape 8 is wound around it.

[0026] The heat-shrinkable tape 8 can be made of polyester tape or polyamide tape. In addition to these materials, the heat-shrinkable tape 8 can also be made of a composite material containing glass fiber or the like to increase its strength. The heat-shrinkable tape shrinks in a direction that cancels the orientation of the resin that is fixed in a stretched and oriented state when heated. In the present disclosure, the shrinkage initiation temperature is preferably in the range of 50°C to 130°C. The shrinkage percentage of the heat-shrinkable tape 8 is preferably 3% or more. The shrinkage initiation temperature can be determined by examining whether or not the heat-shrinkable tape 8 shrinks and deforms when stored at a constant temperature. The shrinkage percentage can be determined by measuring the length of the tape before and after the storage.

[0027] 7 is a cross-sectional view showing the coil conductor in the fourth step of the manufacturing method of the stator coil according to the first embodiment of the present disclosure. In the fourth step, a first heating is applied to the coil conductor 5 that has been subjected to the first three steps, thereby generating a contraction force of the heat-shrinkable tape 8 and curing the prepreg tape 9. Heating within the range of the shrinkage start temperature of the heat-shrinkable tape 8 causes the heat-shrinkable tape 8 to shrink, and the contraction force of the heat-shrinkable tape 8 compresses the mica tape 7 and prepreg tape 9 toward the coil conductor 5. Furthermore, this first heating promotes the curing reaction of the prepreg tape 9, which develops mechanical strength, thereby maintaining the mica tape 7 in a compressed state.

[0028] Because the gaps in the mica tape 7 are filled with air, in the fourth step it is easily compressed by the shrinkage force of the heat-shrinkable tape 8. After compression, a reaction force in the opposite direction to the compression occurs in the mica tape 7, but the prepreg tape 9 is compressed and hardened along the cross section of the mica tape 7. Therefore, the prepreg tape 9, which has high mechanical strength, receives this reaction force, and the mica tape 7 is maintained in its compressed state.

[0029] In this way, by compressing the mica tape 7 before impregnation with the liquid resin, compression is facilitated because no resin is contained between the tapes before impregnation. Furthermore, the manufacturing method of the stator coil of the present disclosure can be applied to coil end portions, which have been difficult to apply pressure compression molding to, and therefore it is possible to improve the voltage resistance and heat dissipation of the coil end portions of the stator compared to conventional manufacturing methods.

[0030] FIG. 8 is a cross-sectional view showing the coil conductor in the fifth and sixth steps of the manufacturing method of the stator coil according to the first embodiment of the present disclosure. In the fifth step, the prepreg tape 9 is cured while generating the contraction force of the heat-shrinkable tape 8. Using the coil in a compressed state, the mica tape 7 is impregnated with liquid resin 10 in a reduced-pressure atmosphere. After impregnation with the liquid resin 10, the coil is pressurized with a gas such as air or nitrogen to impregnate the gaps in the mica tape 7 with the liquid resin 10, thereby suppressing the formation of voids that can cause insulation defects. To prevent the formation of voids, the liquid resin 10 is preferably solvent-free. Examples of suitable resins include epoxy resin, silicone resin, unsaturated polyester resin, and alkyd resin. Since lower viscosity improves impregnation, reactive diluents can be added to these resins. Examples of reactive diluents include acrylate monomers, methacrylate monomers, styrene, vinyl toluene, diallyl phthalate, and monoepoxides. It is preferable that the liquid resin 10 used in the fifth step has a curing temperature different from that of the resin contained in the prepreg tape 9 in the second step, so it is desirable to use a resin different from that of the prepreg tape 9, but a similar resin may also be used.

[0031] In the sixth step, the coil impregnated with the liquid resin 10 is heated for the second time to promote the curing reaction of the liquid resin 10, hardening the liquid resin 10 and integrating the mica tape 7 and the coil conductor 5. The second heating is performed in a temperature range of 90°C to 180°C under normal pressure in order to heat and harden the liquid resin 10. In this way, the stator coil according to this embodiment can be obtained through the first to sixth steps.

[0032] As described above, the method for manufacturing a stator coil according to the present disclosure includes steps 1 to 6. Before the mica tape 7 is impregnated with the liquid resin 10, the mica tape 7 and the prepreg tape 9 are compressed with the heat-shrinkable tape 8, and the resin contained in the prepreg tape 9 is cured and maintained in a compressed state. This prevents excess liquid resin 10 from being trapped between the mica tapes 7 and also prevents the liquid resin 10 from leaking out and creating voids, thereby improving the voltage resistance and heat dissipation of the stator coil.

[0033] Furthermore, in the stator coil manufacturing method of the present disclosure, the mica tape 7 is compressed in advance and this state is fixed with the prepreg tape 9 before the impregnation with the liquid resin 10, so it is possible to omit the step of compressing the mica tape 7 after the impregnation with the liquid resin 10. In conventional stator coil manufacturing methods, excess liquid resin contained between the mica tapes 7 is discharged from the gaps in the mica tapes, so the flow path for the liquid resin is narrow, consisting only of the gaps in the mica tapes 7, and discharging the resin takes time. However, the stator coil manufacturing method of the present disclosure makes it possible to shorten the manufacturing time for the stator coil 3.

[0034] Second Embodiment In a second embodiment, the same components as those in the first embodiment of the present disclosure are designated by the same reference numerals, and descriptions of the same or corresponding parts will be omitted. Hereinafter, a stator coil according to the second embodiment will be described with reference to the drawings.

[0035] FIG. 9 is a cross-sectional view showing a coil insulating material according to the second embodiment of the present disclosure. The first insulating layer 11 and the second insulating layer 12 shown in FIG. 9 are obtained by the stator coil manufacturing method according to the first embodiment, in which liquid resin 10 is impregnated into the gaps between the mica tapes 7 and then cured in a second heating step. As shown in FIG. 9 , the liquid resin 10 is heated and cured in the sixth step to form a cured liquid resin 15. The prepreg tape 9 also contains resin 13 and mica 14. The resin contained in the second insulating layer 12 is obtained by heating the mica 14 before the coil is impregnated and then curing again when the liquid resin 10 forming the first insulating layer 11 is heated.

[0036] In the stator coil according to the second embodiment of the present disclosure, the second insulating layer 12 on the outermost surface of the stator coil 3 is made of mica 14 wound so as not to overlap in the tape width direction, and is characterized by a high level of surface smoothness. The outermost surface of a typical coil is made of mica tape 7 wound so as to overlap in the tape width direction, similar to the first insulating layer 11 of the present invention, with the thickness of each layer of tape being stepped. When the surface of the stator coil 3 is smooth, as in the stator coil according to the present disclosure, the stator coil 3 can be placed in close contact with the surface of the slot 2 when inserted into the slot 2, thereby improving heat dissipation. In this case, a semiconductive sheet or nonlinear resistance material may be placed on the surface of the slot 2 to alleviate the electric field between the coil and the iron core.

[0037] If the mica tape 7 of the first insulating layer 11 is wrapped only around the outermost periphery without overlapping in the tape width direction without using prepreg tape 9 and then impregnated with liquid resin 10, the liquid resin 10 will leak out during heat curing, causing voids that become insulation defects on the surface of the stator coil 3. Furthermore, if a film tape or the like is wrapped around the stator coil 3 to prevent this, heat dissipation will decrease depending on the thickness of the film tape, and the adhesion at the interface between the film tape and mica tape 7 will be poor, causing peeling and destruction of the body when the equipment is in use.

[0038] When the prepreg tape 9 is wrapped around the second insulating layer 12 of the present disclosure without overlapping in the tape width direction, the resin 13 melts uniformly, preventing leakage of the liquid resin 10 during heat curing. To ensure uniform melting of the resin 13, it is desirable for the resin 13 to have a different curing reactivity than the liquid resin 10 used in the first insulating layer 11, a higher curing reactivity than the liquid resin 10, a semi-cured state at room temperature, and a curing reaction that proceeds while melting at a lower temperature than the liquid resin 10 during heating. Furthermore, the liquid resin 10 used in the first insulating layer 11 is a liquid at room temperature and is cured after impregnating the mica tape 7. To prevent leakage of the liquid resin 10, it is desirable for the resin 13 to cure first during heating. Therefore, the first insulating layer 11 and the second insulating layer 12 of the present disclosure preferably have resin compositions with different curing initiation temperatures. Examples of such resins include epoxy resins, etc., from the viewpoint of adhesiveness.

[0039] Third Embodiment In a third embodiment, a stator coil will be described, with the same components as those in the first embodiment of the present disclosure being designated by the same reference numerals.

[0040] 10 is a cross-sectional view taken along the rotation axis of a rotating machine according to a third embodiment of the present disclosure. A rotating machine 16 of the present disclosure includes a stator core 17, fastening members 18, retaining rings 19, a frame 20, intermediate members 21, and elastic support members 22. The fastening members 18 are multiple members that are provided at predetermined intervals in the circumferential direction on the outer periphery of the stator core 17 and fasten the stator core 17 in the axial direction. The retaining rings 19 are provided at predetermined intervals in the axial direction on the outer periphery of the stator core 17 and fasten the stator core 17 in the rotation axis direction from the outer periphery of the core fastening members 18. A cylindrical frame 20, an inner frame member 21, and an elastic support member 22 are provided around the stator core 17 on which the retaining rings 19 are disposed. The inner frame members 21 are multiple ring-shaped members that are provided on the inner surface of the frame 20 at predetermined intervals in the axial direction and protrude in the axial direction. The elastic support members 22 are fixed to adjacent inner frame members 21, and are made of spring plates fixed at their axial centers to retaining rings 19. Figure 10 shows an example in which four retaining rings 19 are arranged on the outer periphery of the stator core 17, and five inner frame members 21 are provided on the inner surface of the frame 20 at predetermined intervals in the axial direction.

[0041] FIG. 11 is a cross-sectional view showing a rotating machine according to a third embodiment of the present disclosure. As shown in FIG. 11 , rotating machine 16 includes a rotor (not shown), a stator 17 arranged coaxially with the rotor and having slots 2 formed on a surface facing the rotor, and stator coils 3 housed in slots 2 of stator 17. FIG. 11 is also a cross-sectional view taken along dashed line A-A' in FIG. 10. FIG. 11 shows an example of rotating machine 16 in which eight core fastening members 18 are provided on the outer periphery of stator 17 and four elastic support members 22 are arranged between retaining ring 19 and inner frame member 21.

[0042] The rotating machine shown here constitutes, for example, an armature for a turbine generator. A predetermined number of axially extending slots are provided circumferentially around the inner periphery of the stator core 17, and stator coils 3 are disposed within the slots. Rotating machines including the stator coils 3 according to the first and second embodiments of the present disclosure can achieve a higher withstand voltage for the stator coils, thereby achieving even higher output and miniaturization. When the configuration of the rotating machine according to the present disclosure is applied to a turbine generator, the increased withstand voltage of the coil insulating material 6 allows the thickness of the insulating material used in the rotating machine to be reduced, thereby reducing heat generation in the coil conductors 5 and improving the output efficiency of the generator.

[0043] The configurations described in the above embodiments are merely examples of the contents of the present disclosure, and may be combined with other known techniques. Furthermore, parts of the configurations may be omitted or modified without departing from the scope of the present disclosure.

[0044] REFERENCE SIGNS LIST 1 stator core, 2 slot, 3 stator coil, 4 wedge, 5 coil conductor, 6 coil insulating material, 7 mica tape, 8 heat shrink tape, 9 prepreg tape, 10 liquid resin, 11 first insulating layer, 12 second insulating layer, 13 resin, 14 mica, 15 hardened liquid resin, 16 rotating machine, 17 stator, 18 core tightening member, 19 retaining ring, 20 frame, 21 inner frame member, 22 elastic support member

Claims

1. A first step of winding a mica tape around a coil conductor obtained by winding a conductor into a coil shape; a second step of winding a prepreg tape around the coil conductor around which the mica tape is wound; a third step of winding a heat shrink tape around the outer periphery of the coil conductor around which the mica tape and the prepreg tape are wound; a fourth step of heating the coil conductor and curing a resin contained in the prepreg tape while compressing the mica tape and the prepreg tape by a contraction force of the heat shrinkable tape; a fifth step of removing the heat shrink tape and impregnating the mica tape with a liquid resin; a sixth step of heating the coil conductor and hardening the liquid resin; A method for manufacturing a stator coil comprising:

2. 2. The method for manufacturing a stator coil according to claim 1, wherein the second step is a step of winding the prepreg tape without overlapping in a width direction of the tape.

3. 2. The method for manufacturing a stator coil according to claim 1, wherein the second step is a step of winding the prepreg tape around a coil end portion of the coil conductor.

4. The method for manufacturing a stator coil according to claim 1 , wherein the prepreg tape has a thickness of 0.1 mm or more and 0.3 mm or less.

5. The amount of resin contained in the prepreg tape is ２ 2. The method for manufacturing a stator coil according to claim 1, wherein the weight is 20 g or more and 200 g or less per unit weight.

6. A coil conductor; a first insulating layer including a mica tape and a hardened liquid resin on an outer periphery of the coil conductor; a second insulating layer formed by wrapping a prepreg tape around an outer periphery of the first insulating layer without overlapping the prepreg tape and curing a resin contained in the prepreg tape; A stator coil comprising:

7. The stator coil according to claim 6 , wherein the first insulating layer and the second insulating layer are made of resins having different compositions.

8. A rotor; a stator core arranged coaxially with the rotor and having slots on a surface facing the rotor; A rotating machine comprising the stator coil according to claim 6 housed in the slot of the stator core.