JP2005341728A - Stator winding of rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a field concentration of corners, even if a thin conductor having thin thickness of a straight angle isolating strand by simplifying the manufacturing work. <P>SOLUTION: A stator winding of a rotary electric machine includes an insulating layer 5 formed by piling up a coil shape, while bundling and flat dislocating a plurality of flat shape strands, multi-layer winding a mica tape constituting by a mica paper, a reinforcing material and an adhesion resin on its outer periphery and forming the insulating layer 5. In the stator winding of the rotary electric machine, a semiconductive intermediate shielding layer 8 is provided at the intermediate of an innermost layer and the outer mediate layer of the thickness direction of the insulating layer 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stator winding of a rotating electrical machine in which a plurality of rectangular wires are bundled and accumulated in a coil shape, and an insulating layer is formed on the outer periphery thereof and accommodated in a stator core.

  In a stator of a high-voltage rotating electrical machine such as a generator or an electric motor, a stator coil 2 is housed in a plurality of slots 1a formed on the inner peripheral side of the stator core 1, as shown in FIG.

  The stator coil 2 includes an upper coil and a lower coil. When the upper coil and the lower coil are housed in a slot, insulating spacers are provided between the slot bottom, the upper and lower coils, and the slot opening. 3 are inserted respectively.

  A slot wedge 4 for fixing the stator coil 2 is inserted into the opening end of the slot 1a to suppress electromagnetic vibration generated from the stator coil 2 during operation of the rotating electrical machine.

  In such a high-voltage rotating electrical machine rotor, the stator coil 2 housed in the slot 1a of the stator core 1 is formed of a conductor having the following configuration.

  First, a plurality of rectangular insulating strands 21 are bundled and subjected to label dislocation, and then a thermosetting resin prepreg separator 11 is disposed between the strand bundle 20a in the left column and the strand bundle 20b in the right column. A prepreg filler 12 of a thermosetting resin is disposed in the dislocation portion.

  Next, the thermosetting resin of the prepreg separator 11 and the prepreg filler 12 is heat-cured while integrally forming the wire bundles 20a and 20b by hot pressing, and the conductor 22 having a final cross-sectional shape is finished.

  An insulating layer 5 generally made of mica paper, a reinforced glass cloth, and a thermosetting resin is provided around the conductor 22 thus obtained. In the vacuum impregnation method, a so-called dry mica tape in which this mica paper and reinforced glass cloth are bonded together with a minimum amount of adhesive is wound around the conductor 22 a plurality of times, and then the thermosetting resin and the mica tape are heated by a hot press. The insulating layer 5 is formed around the conductor 22 by curing.

  When the stator coil 2 having such a configuration is housed in the slot 1a of the stator core 1, the electric field stress generated in the coil insulating layer 5 during operation is not uniform, and the corner portion of the conductor 22 where the electric field concentrates. Is higher than the flat portion of the conductor 22 (for example, Non-Patent Document 1). 291, 1985).

  Therefore, the higher the electric field stress is, the lower the breakdown voltage is and the shorter the electric charging life is. Therefore, the corner portion of the conductor 22 is a weak point of the coil insulating layer 5.

  In fact, the fact that almost all of the breakdown points of the breakdown voltage test in the breakdown voltage test of the insulation coil and the charging life test are the corners of the conductor 22 also supports the existence of the weak point.

By the way, the maximum electric field at the corner of the conductor 22 increases as the radius of curvature of the corner of the conductor 22 becomes smaller as shown in FIG. 5, so that the curvature of the corner is conventionally reduced to alleviate the electric field concentration at the corner. The method of using a strand 21 having a large radius, the method of arranging a semiconductive filler at the label dislocation portion, or winding the semiconductive tape around the outer periphery of the conductor as shown in FIG. The method of forming and enlarging the equivalent curvature radius of a corner | angular part was implemented (for example, nonpatent literature 2).
Proceedings of the IEEJ National Convention, No. 291, 1985 A. Wichmann: IEEE PES Winter Meeting, 82WM235-0, 1982

  However, in the former method, the space factor of the conductor 22 in the slot 1a of the stator core decreases, and as a result, the size of the rotating electrical machine must be increased.

  Further, in the latter method, if an extremely thin semiconductive tape is used, there is little influence on the dimensions of the rotating electrical machine, and there is an effect on the electric field relaxation at the corners of the conductor 22. However, since the maximum value of the radius of curvature that can be provided at the corner is limited by the thickness of the flat insulating wire 21, there is a drawback that the electric field concentration reduction effect is also limited.

  The present invention has been made in view of the circumstances as described above, and can reduce the electric field concentration at the corners even if the conductor of the flat rectangular insulation wire is thin while the manufacturing operation is simple. An object is to provide a stator winding of a rotating electric machine.

  In order to achieve the above object, the present invention forms a stator winding of a rotating electrical machine by the following means.

  In the invention corresponding to claim 1, a plurality of rectangular strands are bundled and accumulated in a coil shape while being displaced, and a plurality of layers of mica tape made of mica paper, a reinforcing material, and an adhesive resin are wound around the outer periphery thereof. In the stator winding of the rotating electrical machine in which the insulating layer is formed, a semiconductive intermediate shield layer is provided between the innermost layer and the outermost layer in the thickness direction of the insulating layer.

  According to a second aspect of the present invention, in the stator winding of the rotating electrical machine according to the first aspect of the present invention, a semiconductive prepreg filler is arranged at the label dislocation portion of a plurality of rectangular wires integrated in a coil shape. To do.

  According to a third aspect of the present invention, in the stator winding of the rotating electrical machine according to the first aspect of the present invention, the intermediate shield layer is formed by winding a semiconductive tape.

  According to a fourth aspect of the present invention, in the stator winding of the rotating electric machine according to the third aspect of the present invention, the semiconductive tape forming the intermediate shield layer is wound at a winding pitch shorter than at least the tape width. The

  According to a fifth aspect of the present invention, in the stator winding of the rotating electric machine according to the first aspect of the present invention, the intermediate shield layer is formed by winding a semiconductive sheet in a spiral shape.

  According to a sixth aspect of the present invention, in the stator winding of the rotating electrical machine according to the first aspect of the present invention, the intermediate shield layer is disposed at a position of 20 to 40% of the insulation thickness from the innermost part of the intermediate insulating layer. .

  According to a seventh aspect of the present invention, in the stator winding of the rotating electrical machine according to the first aspect of the present invention, both ends of the intermediate shield layer in the coil longitudinal direction are outside the potential group grading applied to the coil end surface. Match roughly to the edge.

The invention corresponding to claim 8 is the stator winding of the rotating electrical machine of the invention corresponding to claim 1, wherein the surface resistivity of the intermediate shield layer is 10 ² to 10 ⁵ Ω · cm / cm.

  The invention corresponding to claim 9 constitutes a rotating electrical machine including the stator winding according to any one of claims 1 to 8.

  In the present invention, a semiconductive intermediate shield layer is provided at a position of 20 to 40% of the insulation thickness from the innermost layer of an insulation layer formed by winding a plurality of layers of mica tape on a coil conductor. By reducing the concentration, the insulation strength of the coil is improved, and as a result, the insulation thickness can be reduced to reduce the size and weight of the rotating electrical machine.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 are a transverse sectional view and a longitudinal sectional view, respectively, showing a first embodiment of a stator winding of a rotating electrical machine according to the present invention.

  1 and 2, the configuration up to bundling flat insulated wires 21 and performing label dislocation, and disposing the thermosetting prepreg separator 11 between the left and right strand bundles 20a and 20b is the diagram described in the prior art. Since the configuration is the same as that of No. 4, the description thereof is omitted. Here, the subsequent formation of the conductor 22 and the insulating layer 5 formed around the conductor 22 will be described.

  In the first embodiment, a semi-conductive prepreg filler 13 is disposed at the label dislocation portion of the strands 20a and 20b, and the strands 20a and 20b are integrally formed by hot pressing, and the prepreg separator 11 is formed. After the thermosetting resin of the semiconductive prepreg filler 13 is heated and cured, the semiconductive prepreg filler 13 at the corners of the conductor 22 is polished to a predetermined radius of curvature.

This semiconductive prepreg / filler 13 is made into a putty by mixing carbon powder together with aluminum powder, mica powder, etc. in an epoxy resin, and the specific resistivity after curing the epoxy resin is 10 ² to 10 ⁵ Ω · cm. is there. If the resistance value is lower than this, the eddy current loss generated in the interior due to the magnetic flux traversing the stator slot during operation increases, and if the resistance value is higher than this, the electric field relaxation effect at the conductor corner cannot be expected.

  A plurality of layers of dry mica tape are wound around the conductor 22.

That is, first, 30% of the total number of turns of the dry mica tape is wound, and the semiconductive tape 14 having a surface resistivity of 10 ² to 10 ⁵ Ω · cm / cm is laid on the lap twice. Intermediate shield layer 8 is formed.

  The semiconductive tape 14 is a sheet obtained by mixing aramid fibers and carbon fibers and slit into a tape shape.

  In this case, the winding range of the semiconductive tape 14 is applied to the end surface of the coil as shown in FIG. The SiC potential grading 7 is made to protrude slightly outward.

  Further, the winding pitch of the tape is not limited to 1/2 lap winding, but it is necessary to form a continuous shield surface by making it at least shorter than the tape width and overlapping the winding tapes.

  Further, the remaining 70% of dry mica tape is wound on top of it.

  Next, the dry mica tape layer and the intermediate shield layer 8 are vacuum-impregnated with an epoxy resin, and while the coil 2 is formed into a final cross-sectional shape, the impregnated resin and the mica tape layer are integrally heated and cured by hot pressing, An insulating layer 5 is formed around the conductor 22.

  FIG. 3 is a graph showing the effect of the insertion position of the intermediate shield layer 8 on the electric field inside the insulation for the coil insulation having such a configuration.

  As can be seen from the graph shown in FIG. 3, when the insertion position of the intermediate shield layer 8 is moved from the insulating inner layer toward the insulating outer layer, the electric field at the corner of the conductor 22 once decreases and reaches a minimum around 10% from the inner layer. After showing the value, it rises towards the outer layer and back to its original position.

  On the other hand, the electric field at the corner of the inserted intermediate shield layer 8 gradually decreases as the insertion position moves from the insulating inner layer toward the insulating outer layer.

  From this result, in order to reduce the maximum electric field at the corner and make the electric field inside the insulating layer 5 uniform, it is most effective to arrange the intermediate shield layer 8 at a position of 20 to 40% from the insulating inner layer. I understand that there is.

  Since the mica tape usually has a thickness of about 0.1 to 0.3 mm, the insertion position of the intermediate shield layer 8 is restricted by the thickness of the mica tape. Therefore, in actuality, it is appropriately selected within the range of 20 to 40%.

  As described above, according to the first embodiment of the present invention, by providing the semiconductive intermediate shield layer 8 in the middle of the innermost layer in the thickness direction of the insulating layer 5, the thickness of the flat conductor element wire 21 is increased. Even if the conductor 22 is thin, the maximum electric field inside the corner insulating layer, which is a weak point of coil insulation, can be reduced.

  Furthermore, since the stator winding 2 having such a configuration is a stator housed in the slot 1a of the stator core 1, the insulation thickness can be reduced, which can contribute to downsizing of the device.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  In the second embodiment, a semi-conductive prepreg filler 13 is disposed at the label dislocation portion of the strands 20a and 20b, and the strands 20a and 20b are integrally formed by hot pressing, while the prepreg separator 11 is formed. After the thermosetting resin of the semiconductive prepreg filler 13 is heated and cured, the semiconductive prepreg filler 13 at the corners of the conductor 22 is polished to a predetermined radius of curvature.

  A plurality of layers of dry mica tape are wound around the conductor 22.

That is, first, about 30% of the total number of turns of the dry mica tape is wound, and the semi-conductive sheet 15 having a surface resistivity of 10 ² to 10 ⁵ Ω · cm / cm is overlapped thereon and wound once. The intermediate shield layer 8 is formed by winding.

  This semiconductive sheet 15 is obtained by uniformly applying a semiconductive varnish mixed with carbon powder onto a polyester nonwoven fabric and heat-curing it. The wound sheet has at least a stacking allowance and needs to form a continuous shield surface.

  In this case, the winding range of the semiconductive sheet 15 is such that the SiC applied to the surface of the coil end so that the disturbance of the electric field in the vicinity of both edge portions of the intermediate shield layer 8 does not affect the insulation strength of the coil slot. It matches with the outer end of the potential grating 7.

  Further, the remaining 70% of dry mica tape is wound on top of it.

  Next, the dry mica tape layer and the intermediate shield layer 8 are impregnated with an epoxy resin under vacuum, and the impregnated resin and the mica tape layer are integrally heated and cured by hot pressing while the coil 2 is formed into a final cross-sectional shape. An insulating layer 5 is formed around 22.

  Thus, also by the second embodiment, the same effect as that of the first embodiment can be obtained.

  Next, a third embodiment of the present invention will be described with reference to FIGS.

  In the third embodiment, the semiconductive prepreg filler 13 is disposed at the label dislocation portion of the strands 20a and 20b, and the strands 20a and 20b are integrally formed by hot pressing, and the prepreg separator 11 is formed. After the thermosetting resin of the semiconductive prepreg filler 13 is heated and cured, the semiconductive prepreg filler 13 at the corners of the conductor 22 is polished to a predetermined radius of curvature.

  A plurality of resin-rich mica tapes are wound around the conductor 22.

That is, the resin-rich mica tape is first wound by 30% of the total number of turns, and is laid on the semi-conductive tape having a surface resistivity of 10 ² to 10 ⁵ Ω · cm / cm by ½ lap.

  In this case, the winding range of the semiconductive tape is such that the SiC potential applied to the surface of the coil end so that the disturbance of the electric field in the vicinity of both edge portions of the intermediate shield layer 8 does not affect the insulation strength of the coil slot. From the outer end of the grading 7 to slightly inside.

  Further, the remaining 70% of dry mica tape is wound on top of it.

  Next, the resin-rich mica tape layer and the intermediate shield layer 8 are integrally heated and cured by hot pressing to form the insulating layer 5 around the conductor 22.

  According to the third embodiment as described above, the same effect as that of the first embodiment can be obtained.

The cross-sectional view of the stator coil for demonstrating the insertion position of the intermediate | middle shield layer in the 1st Embodiment of this invention thru | or 3rd Embodiment. Similarly, the longitudinal cross-sectional view of the stator coil for demonstrating the longitudinal direction length of an intermediate | middle shield layer. The graph which similarly shows the effect which the insertion position of an intermediate | middle shield layer has on the electric field inside a coil insulation. The cross-sectional view of the stator slot part which shows the structure of the conventional stator coil. The graph which shows the effect which the curvature radius of a conductor corner has on the maximum electric field of a conductor corner. The perspective view which shows the conventional stator coil which formed the inner shield in the conductor outer periphery.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Stator iron core, 1a ... Slot, 2 ... Stator coil, 3 ... Insulating spacer, 4 ... Slot wedge, 5 ... Insulating layer, 6 ... Inner shield layer, 7 ... SiC potential grading, 8 ... Middle shield layer, 11 Prepreg separator, 12 prepreg filler, 13 semiconductive prepreg filler, 14 semiconductive tape, 20a, 20b strand bundle, 22 coil conductor

Claims (9)

Fixing a rotating electrical machine in which a plurality of rectangular wires are bundled and accumulated in a coil shape while being label-dislocated, and multiple layers of mica tape composed of mica paper, reinforcing material, and adhesive resin are wound around it to form an insulating layer In the child winding,
A stator winding for a rotating electrical machine, wherein a semiconductive intermediate shield layer is provided between the innermost layer and the outermost layer in the thickness direction of the insulating layer.   The stator winding of the rotating electric machine according to claim 1, wherein a semiconductive prepreg filler is disposed at a label dislocation portion of a plurality of flat wire elements integrated in a coil shape, and the wire is consolidated. Electric stator winding.   The stator winding for a rotating electrical machine according to claim 1, wherein the intermediate shield layer is formed by winding a semiconductive tape.   The stator winding of a rotating electric machine according to claim 3, wherein the semiconductive tape forming the intermediate shield layer is wound at a winding pitch shorter than at least the tape width. line.   2. A stator winding for a rotating electrical machine according to claim 1, wherein the intermediate shield layer is formed by winding a semiconductive sheet in a spiral shape.   The stator winding for a rotating electrical machine according to claim 1, wherein the intermediate shield layer is disposed at a position of 20 to 40% of the insulation thickness from the innermost part of the intermediate insulating layer. .   The stator winding of a rotating electrical machine according to claim 1, wherein both ends of the intermediate shield layer in the longitudinal direction of the coil are substantially matched with outer ends of the potential group grading applied to the coil end surface. Stator winding. The stator winding for a rotating electrical machine according to claim 1, wherein the intermediate shield layer has a surface resistivity of 10 ² to 10 ⁵ Ω · cm / cm.   A rotating electrical machine comprising the stator winding according to any one of claims 1 to 8.

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