JP4675741B2 - Stator coil of rotating electric machine - Google Patents

Description

  The present invention relates to a stator coil used in a rotating electrical machine, and more particularly to an improvement in a ground insulating layer provided for insulating a coil conductor constituting a stator coil of a high voltage rotating electrical machine.

  In general, a stator of a rotating electrical machine is configured such that a stator coil is housed in a slot of a stator core. In particular, a stator coil used in a high-voltage rotating electrical machine has a ground main insulating layer formed on the outer periphery of a coil conductor. In addition, a low resistance corona shield layer is formed on the outer periphery of the main ground insulating layer at the slot mounting location of the stator coil. Then, a thermosetting resin is impregnated by vacuum pressing or the like to the ground main insulating layer and the corona shield layer so that no air remains in the ground main insulating layer and the corona shield layer, and then heat curing treatment Is done.

  The above-mentioned main ground insulating layer is for insulating the coil conductor from the stator core, and is conventionally configured by winding a number of mica tapes excellent in partial discharge resistance so as to partially overlap. . The mica tape used in this case is configured, for example, by integrally joining a reinforcing backing material to the laminated mica layer with an adhesive or the like. The backing material is made of glass fiber or a woven or non-woven fabric of polymer fiber such as polyester or polyamide.

  On the other hand, the corona shield layer described above is for preventing partial discharge due to a potential difference between the main ground insulating layer and the slot when the stator coil is mounted in the slot. The tape is wound around the insulating ground layer so as to partially overlap each other.

  Conventionally, the conductive tape used in this case is, for example, glass fiber or polymer fiber woven or non-woven fabric such as polyester, polyamide, etc. mixed with powder or fiber of conductive material such as carbon or graphite into resin. The coating composition is applied or impregnated, or is made of a mixed paper obtained by spreading carbon fibers together with polymer fibers.

  By the way, as described above, when the stator coil is manufactured, the thermosetting resin is immersed in the impregnation tank and impregnated into the main insulation layer and the corona shield layer, and then the impregnation resin is heated in a drying furnace. Although it hardens, when the stator coil is pulled up from the impregnation tank, a part of the impregnation resin leaks out of the stator coil, or the viscosity of the impregnation resin decreases due to the temperature rise at the time of heat curing, and it tends to flow, Part of the impregnating resin may leak from the stator coil. As a result, a void may be generated in the ground-side insulating layer or in the boundary portion between the ground-side insulating layer and the corona shield layer. If air gaps exist inside the ground insulating layer or at the boundary between the ground insulating layer and the corona shield layer, discharge occurs in these air gap portions due to high voltage during operation.

  Here, even if a gap is generated inside the ground insulating layer, the influence of the partial discharge is relatively slight because the periphery is surrounded by mica tape having excellent partial discharge resistance. On the other hand, when a discharge occurs in the gap that exists at the boundary between the main earth insulating layer and the corona shield layer, conductive materials such as carbon and graphite are scattered to give the corona shield layer low resistance. As a result, the corona shield layer itself may disappear. Then, since the corona shield effect of the corona shield layer is lost, an even greater discharge is generated between the main earth insulation layer and the stator core, resulting in damage to the main earth insulation layer and eventually causing dielectric breakdown. There is a fear.

  Therefore, as a countermeasure, the conventional technique uses a semiconductive tape formed by integrally forming a laminated mica layer on one side of the polymer film substrate and a semiconductive layer on the other side. There has been proposed a structure in which a corona shield layer is formed by winding this semiconductive tape around the main ground insulating layer with the semiconductive layer on the outside (for example, Patent Document 1). , 2).

  When the corona shield layer is formed using the semiconductive tape having the configuration described in Patent Documents 1 and 2, the laminated mica layer is excellent in partial discharge resistance, thereby reducing the influence of partial discharge. it can. In addition, since the polymer film substrate does not allow the resin to permeate, when the impregnated resin is heat-cured, a part of the impregnated resin leaks out of the stator coil, and a gap is formed at the boundary between the ground insulating layer and corona shield layer It is possible to reduce the occurrence of defects such as the formation of a certain extent.

JP-A-8-237916 JP 2003-259589 A

  However, the configurations described in Patent Documents 1 and 2 have the following problems. That is, since the polymer film substrate, which is a constituent material of the semiconductive tape, does not permeate the resin, the resin impregnation path from the surface of the corona shield layer is limited only to the laminated mica layer. For this reason, it is difficult to impregnate the main land insulating layer with the resin via the corona shield layer, there is a risk that impregnation failure may occur, and the impregnation treatment time becomes long.

  In addition, since the polymer film base material has a weak strength against scratching and tearing, there is a problem that the polymer film base material may be damaged during the manufacturing operation of the stator coil. Furthermore, in order to improve the resin impregnation property, when forming the corona shield layer, it is conceivable to reduce the overlapping portion when the semiconductive tape is wound around the ground insulating layer. A gap may be generated due to a change in the winding position, and the reliability as the corona shield layer is lacking.

  The present invention has been made in order to solve the above-mentioned problems, and while ensuring good resin impregnation properties, no voids are generated at the boundary between the outermost peripheral portion of the ground-main insulating layer and the corona shield layer. It is an object of the present invention to provide a highly reliable stator coil for a rotating electrical machine that suppresses the occurrence of partial discharge by taking various measures.

  In order to achieve the above object, the present invention provides a ground main insulating layer formed by winding a mica tape many times around the outer periphery of a coil conductor, and a ground main insulating layer at a position corresponding to a slot of a stator core. In the stator coil of a rotating electrical machine, a corona shield layer having a low resistance is formed on the outer periphery of the rotor, and the above-mentioned ground main insulating layer and the corona shield layer are impregnated with a thermosetting resin and cured. Is adopted.

That is, the stator coil of the present invention has an impregnation resin outflow containing an inorganic material on at least the outermost surface of the mica tape constituting the ground-main insulating layer and in contact with the corona shield layer. It is characterized in that a filler for prevention is applied.

  According to this invention, the filler which has an inorganic material is apply | coated to the surface of the side which contacts the corona shield layer and is located in the outermost periphery in the mica tape which comprises a ground main insulating layer. This filler contains an adhesive that holds the inorganic material on the mica tape, and a material compatible with the impregnating resin is used as the adhesive. For this reason, when the resin is impregnated, the filler applied to the outermost mica tape is mixed with the impregnated resin and eluted. For this reason, the viscosity of the mixture of the impregnating resin and the eluted filler is increased and the fluidity is lowered. As a result, even when the stator coil is pulled up from the impregnation tank, or even when the temperature of the impregnation resin rises at the time of heat curing, the resin present at the boundary portion between the main ground insulating layer and the corona shield layer flows out to the outside. It is suppressed and the space | gap in the part becomes difficult to be formed. As a result, discharge does not occur in the portion immediately below the corona shield layer, and the corona shield layer does not disappear due to discharge, and the corona shield effect can be maintained over a long period of time. It becomes possible to provide a stator coil.

  Moreover, since the polymer film base material described in Patent Documents 1 and 2 is not used as a material for constituting the corona shield layer or the main ground insulating layer, the resin impregnation property may be impaired. Absent. For this reason, there is no possibility that the impregnation treatment time will be prolonged and impregnation failure will not occur.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing a part of a stator coil mounted in a slot of a stator core constituting a rotating electric machine according to Embodiment 1 of the present invention, and FIG. FIG. 3 is a cross-sectional view schematically showing an enlarged portion indicated by symbol A in FIG. 2, and FIG. 4 is an outermost view of the mica tape constituting the ground insulating layer. It is sectional drawing which shows the part which is located.

  In the first embodiment, a stator coil 3 is housed in a slot 2 provided in the stator core 1, and an end portion of the stator coil 3 is drawn out of the slot 2. The stator coil 3 has a coil conductor 4 formed by bundling a plurality of insulated conductors 4 a, and a ground insulating layer 5 is formed on the outer periphery of the coil conductor 4.

  Further, a low-resistance corona shield layer 6 is formed on the outer periphery of the ground main insulating layer 5 at the slot mounting location of the stator coil 3. Further, a high-resistance corona shield layer 8 is formed at a portion of the stator coil 3 protruding from the slot 2 so as to cover the ground main insulating layer 5 and to be connected to the corona shield layer 6. In addition, thermosetting resin such as epoxy resin is impregnated and cured with respect to the main land insulating layer 5 and the corona shield layers 6 and 8.

  The ground main insulating layer 5 is for electrically insulating the coil conductor 4 from the stator core 1, and the mica tape 10 having excellent partial discharge resistance is partially overlapped on the outer periphery of the coil conductor 4. It is configured to be wound many times. In FIG. 3, for the convenience of illustration, the number of windings of the mica tape 10 is less than the actual number.

  Here, the mica tape 10 includes, for example, a laminated mica layer 11 made by making mica powder, and a reinforcing backing material 12 made of a woven or non-woven fabric of glass fibers or polymer fibers such as polyester or polyamide. And both 11 and 12 are integrally joined with an adhesive or the like. Then, the ground main insulating layer 5 is formed by winding the coil conductor 4 a number of times so that the backing material 12 is outside the laminated mica layer 11 and the mica tape 10 partially overlaps each other. ing. Instead of the laminated mica layer 11, a peeled mica layer can be used.

  In addition, as a feature of the first embodiment, the outer peripheral surface of the outermost mica tape 10 in contact with the corona shield layer 6 among the mica tape 10 wound many times in this way is a filler 13 having an inorganic material. Is applied. Therefore, the outermost mica tape 10 is in a state in which the filler 13 is applied on the backing material 12 as shown in FIG.

  The filler 13 is mixed with, for example, an inorganic material with a resin or mixed with a solvent if the mixture has a viscosity, and this is applied to the outer peripheral surface of the outermost mica tape 10 in contact with the corona shield layer 6. Is formed. Examples of the inorganic material used for the filler 13 include zinc oxide, silicon oxide, sialon, iron trioxide, iron tetraoxide, titanium oxide, silicon carbide, aluminum nitride, aluminum oxide, magnesium oxide, and nitride. Common inorganic materials such as silicon, boron nitride, beryllium oxide, mica, boehmite, titanate, and glass can be applied.

  On the other hand, the corona shield layer 6 is for preventing partial discharge from being generated due to a potential difference between the main ground insulating layer 5 and the slot 2 when the stator coil 3 is mounted in the slot 2. The conductive tape 14 is wound around the ground main insulating layer 5 so as to partially overlap each other.

  The conductive tape 14 in this case has the same configuration as that of the prior art. For example, a conductive fiber such as carbon, graphite, iron powder, iron oxide or the like is applied to a woven or non-woven fabric of polymer fiber such as glass fiber or polyester or polyamide. It is made of a mixed material obtained by applying or impregnating a coating material obtained by mixing a powder or fiber of a functional material into a resin, or by dispersing carbon fibers together with polymer fibers.

  The high-resistance corona shield layer 8 is for preventing discharge at the end of the low-resistance corona shield layer 6 of the stator coil 3 drawn out from the slot 2, and has a special configuration similar to the conventional one. It can be used without any restrictions. Reference numeral 9 denotes a coil retainer for preventing the stator coil 3 from protruding from the slot 2.

  When manufacturing the stator coil 3 having the above configuration, first, the coil conductor 4 is manufactured by bundling a plurality of insulated wire conductors 4a. Then, the mica tape 10 is wound around the coil conductor 4 so that the backing material 12 is on the outside and the mica tape 10 is partially overlapped with each other to be wound many times (for example, 10 to 15 times). 5 is formed. Next, the filler 13 is applied to the outer peripheral surface of the outermost mica tape 10 in contact with the corona shield layer 6. In addition, before the mica tape 10 is wound around the coil conductor 4, the filler 13 may be applied in advance to the winding end portion of the mica tape 10.

  Next, the low resistance corona shield layer 6 is formed by winding the conductive tape 14 around the portion corresponding to the portion to be attached to the slot 2 so as to partially overlap each other. A high-resistance corona shield layer 8 is formed at the end of the stator coil 3 so as to be connected to the low-resistance corona shield layer 6.

  Stator coil 3 formed in this manner is placed in an impregnation tank, and thermosetting resin such as epoxy resin is vacuum-pressurized and impregnated. Then, after the corona shield layer 6 and the earth main insulating layer 5 are sufficiently impregnated with the resin, the resin is taken out from the impregnation tank, and then put into a drying furnace to be heated and cured.

  As described above, conventionally, when the stator coil 3 is pulled up from the impregnation tank, a part of the resin leaks out of the stator coil 3, or the temperature of the impregnation resin rises at the time of heat curing and the viscosity decreases. It becomes easy to flow and a part of the resin leaks from the stator coil 3. In particular, the resin impregnated in the boundary portion between the main ground insulating layer 5 and the corona shield layer 6 is likely to leak to the outside, and as a result, a gap is formed in the winding step portion 18 on the outermost periphery of the mica tape 10. The high voltage during operation causes discharge in these gaps, causing problems such as loss of the corona shield layer 6.

  On the other hand, in this Embodiment 1, the filler 13 which has an inorganic material in the surface which is located in the outermost periphery of the mica tape 10 which comprises the earth main insulating layer 5, and is in contact with the corona shield layer 6 is used. Thus, when the stator coil 3 is placed in the impregnation tank and impregnated, the boundary portion between the main ground insulating layer 5 and the corona shield layer 6 is impregnated with resin. At this time, the filler 13 applied to the outermost mica tape 10 is mixed with the impregnating resin. Therefore, the viscosity of the mixture of the impregnating resin and the eluted filler 13 is increased and the fluidity is lowered. As a result, even when the stator coil 3 is pulled up from the impregnation tank or the temperature of the impregnation resin rises at the time of heat curing, the impregnation resin existing at the boundary portion between the main ground insulating layer 5 and the corona shield layer 6 is exposed to the outside. Leakage is suppressed, and a gap is less likely to be formed in the winding step portion 18 of the mica tape 10 present at the boundary portion with the corona shield layer 6.

  FIG. 5 is a characteristic diagram showing the relationship between the mixing ratio of the filler 13 and the viscosity of the resin when the filler 13 using titanium oxide as an inorganic material is mixed with the impregnating resin. As can be seen from the figure, it is understood that the viscosity rapidly increases as the mixing ratio of the filler 13 increases. As described above, when the viscosity of the impregnating resin increases as the mixing ratio of the filler 13 increases, the fluidity of the impregnating resin decreases, so that the impregnating resin hardly leaks to the outside through the corona shield layer 6.

  6A and 6B, when the mica tape 10 is wound around the coil conductor 4 to form the ground main insulating layer 5, the mica tape 10 coated with the filler 13 is wound around the outermost periphery, and the filler 13 is applied as in the conventional case. It is the characteristic view which investigated the relationship between the magnitude | size and generation | occurrence | production frequency of the space | gap which generate | occur | produces in the boundary part of the earth main insulating layer 5 and the corona shield layer 6 in each when not using.

  As can be seen from the figure, in the case of the present invention in which the mica tape 10 coated with the filler 13 is wound around the outermost periphery, the viscosity of the impregnating resin is increased and leakage is suppressed, so that voids are less likely to occur. It is understood that both the size and the frequency of are smaller than the conventional case.

  Thus, in this Embodiment 1, since the mica tape 10 which apply | coated the filler 13 was wound around the outermost periphery, and the earth main insulating layer 5 was comprised, it applied to the mica tape 10 in the case of resin impregnation. As a result of the filler 13 being mixed with the impregnating resin and increasing the viscosity of the mixture, the impregnating resin is prevented from leaking outside. Therefore, it becomes difficult to form a gap in the winding step portion 18 of the mica tape 10 existing at the boundary portion with the corona shield layer 6, and partial discharge directly below the corona shield layer 6 does not occur. As a result, the corona shield layer 6 does not have a problem such as disappearance due to discharge, the corona shield effect can be maintained for a long time, and the highly reliable stator coil 3 of the rotating electrical machine can be provided. .

  In addition, since the polymer film base material described in Patent Documents 1 and 2 is not used as a material for constituting the ground main insulating layer 5 or the corona shield layer 6, the resin impregnation property is impaired. There is nothing. For this reason, there is no possibility that the impregnation treatment time will be prolonged and impregnation failure will not occur.

  In the first embodiment, the filler 13 is locally applied only to the surface of the outermost mica tape 10 on the side in contact with the corona shield layer 6. Before the mica tape 10 is wound, the filler 13 can be applied in advance over the entire length of the mica tape 10. In this way, not only can the air gap be prevented from being generated at the boundary between the main ground insulating layer 5 and the corona shield layer 6, but also the air gap can be prevented from being generated inside the main ground insulating layer 5. Conveniently, the occurrence of partial discharge due to high voltage during operation can be further suppressed.

Embodiment 2. FIG.
FIG. 7 is a cross-sectional view showing a portion located on the outermost periphery of the mica tape constituting the main ground insulating layer in the second embodiment of the present invention, and corresponds to the first embodiment shown in FIGS. 1 to 3. The same reference numerals are given to the constituent parts.

  In the first embodiment described above, the filler 13 is applied on the backing material 12 in the portion located on the outermost periphery of the mica tape 10 constituting the ground-main insulating layer 5. On the other hand, in the second embodiment, the laminated mica layer 11 is wound around the coil conductor 4 so as to be outside of the backing material 12. Moreover, the outermost mica tape 10 in contact with the corona shield layer 6 has a configuration in which a filler 13 is applied to the outer peripheral surface of the laminated mica layer 11.

  Also in the case of the configuration of the second embodiment, the same effects as those of the first embodiment can be obtained. Other configurations are the same as those in the first embodiment, and thus detailed description thereof is omitted here.

Embodiment 3 FIG.
FIG. 8 is a perspective view schematically showing a portion located on the outermost periphery of the mica tape constituting the ground-main insulating layer in the third embodiment of the present invention, and the embodiment shown in FIGS. Constituent elements corresponding to 1 are denoted by the same reference numerals.

  The feature of this third embodiment is that the backing material 12 of the mica tape 10 that constitutes the ground-main insulating layer 5 is composed of a woven cloth with a rough mesh. The mica tape 10 is wound around the coil conductor 4 so that the backing material 12 is outside of the laminated mica layer 11, and the outermost mica tape 10 in contact with the corona shield layer 6 is wound around the coil conductor 4. The filler 13 is applied to the outer peripheral side of the backing material 12. In addition, as a raw material of the woven fabric used as the backing material 12, for example, glass fibers or polymer fibers such as polyester or polyamide can be applied as in the case of the first embodiment.

  In the case where the backing material 12 of the mica tape 10 is formed of a woven cloth having a rough mesh as in the third embodiment, when the filler 13 is applied to the backing material 12, the inorganic material constituting the filler 13 is It is carried between the meshes of this woven fabric. For this reason, it can suppress that the thickness of the mica tape 10 increases. In this case, if a backing material 12 having a thickness of 0.025 mm to 0.05 mm is used, the particle size of the inorganic material is 0.025 mm or less, preferably 0.015 mm or less. Is preferably used.

Here, when the thickness of the mica tape 10 is increased as a whole, the winding step 18 is increased, wrinkles are easily generated during winding, and the thermal resistance of the entire ground insulating layer 5 is increased, so that the stator coil is increased. However, in the third embodiment, since the thickness of the mica tape 10 can be suppressed and the thickness can be made equal to the conventional one, the occurrence of these problems can be avoided. it can.
Since other configurations and operational effects are the same as those in the first embodiment, detailed description thereof is omitted here.

Embodiment 4 FIG.
FIG. 9 is a perspective view schematically showing a portion located on the outermost periphery of the mica tape constituting the ground-main insulating layer in Embodiment 4 of the present invention, and FIG. 10 is a longitudinal sectional view thereof. Components corresponding to those of the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals.

  In the fourth embodiment, the mica tape 10 that constitutes the ground-main insulating layer 5 is wound around the coil conductor 4 so that the laminated mica layer 11 is outside the backing material 12, and the corona The outermost mica tape 10 in contact with the shield layer 6 has a configuration in which a filler 13 having a scaly inorganic material is applied to the outer peripheral surface of the laminated mica layer 11. Examples of such a scaly inorganic material include mica, boron nitride, silicon dioxide, boehmite, titanate, and scaly glass flakes.

If the scale-like thing is used as the inorganic material of the filler 13 like this Embodiment 4, it can suppress that the thickness of the mica tape 10 increases. For this reason, as in the case of the third embodiment, the winding step 18 becomes large, wrinkles are generated at the time of winding, and the thermal resistance of the entire ground insulating layer 5 increases, so that the temperature of the stator coil 3 increases. There is an advantage that it is possible to avoid the occurrence of problems such as rising.
Other configurations and operational effects are the same as those in the first embodiment, and thus detailed description thereof is omitted here.

In Embodiment 1 of this invention, it is a perspective view which shows a part of the state which attached the stator coil to the slot of the stator core which comprises a rotary electric machine. In Embodiment 1 of this invention, it is sectional drawing which shows a part of the state which mounted | wore the stator coil with the slot of the stator core. It is sectional drawing which expands and shows typically the part shown with the code | symbol A of FIG. In Embodiment 1 of this invention, it is sectional drawing which shows the part located in the outermost periphery of the mica tape which comprises a ground main insulating layer. It is a characteristic view which shows the relationship between the mixing ratio of a filler, and the viscosity of resin when the filler which uses a titanium oxide as an inorganic material is mixed with an impregnation resin. When the mica tape is wound around the coil conductor to form the ground-main insulating layer, the land-owner is divided into the case where the mica tape coated with the filler is wound around the outermost periphery and the case where the filler is not used as in the conventional case. It is the characteristic view which investigated the relationship between the magnitude | size and generation | occurrence | production frequency of the space | gap which generate | occur | produces in the boundary part of an insulating layer and a corona shield layer. In Embodiment 2 of this invention, it is sectional drawing which shows the part located in the outermost periphery of the mica tape which comprises a ground main insulating layer. In Embodiment 3 of this invention, it is a perspective view which shows typically the part located in the outermost periphery of the mica tape which comprises a ground main insulating layer. In Embodiment 4 of this invention, it is a perspective view which shows typically the part located in the outermost periphery of the mica tape which comprises a ground main insulating layer. It is a longitudinal cross-sectional view which shows the part located in the outermost periphery of the mica tape.

Explanation of symbols

1 stator core, 2 slots, 3 stator coils, 4 coil conductors,
5 ground insulating layer, 6 corona shield layer, 10 mica tape, 11 laminated mica layer, 12 backing material, 13 filler, 18 winding step.

Claims (3)

The ground conductor insulation layer is formed by winding a large number of mica tapes on the outer periphery of the coil conductor, and the low resistance corona shield layer is formed on the outer periphery of the ground insulation layer at the location corresponding to the slot of the stator core. In the stator coil of the rotating electrical machine, the resin is impregnated and cured with respect to the ground main insulating layer and the corona shield layer.
Of the mica tape constituting the ground-main insulating layer, at least the outermost surface located on the side in contact with the corona shield layer is coated with a filler for preventing impregnation resin outflow having an inorganic material. A stator coil for a rotating electrical machine. In the mica tape, the backing material is integrally joined to the mica layer, and the backing material is composed of a woven fabric. The filler is applied to the surface of the woven fabric that is not joined to the mica layer. The stator coil for a rotating electrical machine according to claim 1, wherein the stator coil is formed. The stator coil for a rotating electrical machine according to claim 1 or 2, wherein the inorganic material used for the filler is a scale-like material.

Images