Rotating electrical machine

Abstract

The present invention comprises: a retaining ring (5), the retaining ring (5) being engaged with the rotor (1) to retain the rotor coil (15) of the rotor (1); and an inter-pole jumper (13), the inter-pole jumper (13) being composed of a flexible lead (17) formed by stacking conductive metal plates and a metal wire (13a) connected to the flexible lead (17), electrically connecting the excitation poles of the rotor (1) to each other, and being configured so that, when the radial positions of the metal plates of the flexible lead (17) are divided based on half the total number of stacked metal plates, the average thickness of the plates arranged on the inner layer side is smaller than the average thickness of the plates arranged on the outer layer side.

Description

Technical Field

[0001] The present application relates to rotating electrical machines. Background Art

[0002] Rotating electrical machines such as turbine generators have a rotor and a stator. An excitation winding is wound around the rotor. By flowing current through the excitation winding and rotating the rotor using the power of the prime mover, a rotating magnetic field is generated, and the stator winding generates an output current. The rotor usually has two or four excitation poles, and the poles are electrically connected to each other by interpole jumpers installed at the ends of the rotor. The interpole jumper is annular and has a flexible lead at the center of the poles. The flexible lead is a structure made by stacking multiple copper plates of the same thickness in a curved shape, and is flexible. The two ends of the flexible lead are connected to the interpole jumper by brazing. The outer diameter side of the interpole jumper and the flexible lead is covered by an annular retaining ring that is heat-fitted to the end of the rotor. An insulating block is sandwiched between the interpole jumper and the flexible lead and the retaining ring.

[0003] In the aforementioned rotating electrical machine, the centrifugal force during rotation causes the retaining ring's radius to expand, causing the insulating block to move outward. This expansion also causes the inter-pole jumper's radius to expand along the insulating block, allowing the flexible lead to absorb the circumferential extension. This circumferential extension generates a bending moment in the flexible lead's center. This bending moment creates bending stress in the center of each layer of the flexible lead, causing tension on the inner diameter and compression on the outer diameter. In this case, the bending stress increases in the innermost layers with greater curvature, with the maximum stress occurring in the center of the innermost layer.

[0004] When this maximum stress becomes excessively high, there is a possibility that fatigue failure may occur due to repeated starting and stopping in extreme cases.

[0005] To prevent this, some conventional rotating electrical machines employ deformation prevention members in contact with the flexible lead to reduce stress generated in the central portion of the flexible lead (Patent Document 1). Alternatively, some conventional rotating electrical machines employ a longer radial length of the flexible lead to reduce stress generated in the central portion of the flexible lead (Patent Document 2).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 62-104446 (page 2, lines 37-42, Figure 2 )

[0009] Patent Document 2: Japanese Patent Publication No. 62-031577 (page 2, lines 48-57, Figure 8 ) Summary of the Invention

[0010] Problems to be solved by the invention

[0011] In such rotating electrical machines, additional components or changes to the flexible lead's shape have been implemented to reduce the maximum stress generated in the flexible lead. However, this approach cannot maintain the conventional ventilation path, hindering cooling and reducing power generation efficiency. Furthermore, it is not applicable where there are space constraints around the flexible lead.

[0012] The present application discloses a technology for solving the above-mentioned problems, and aims to maintain conventional cooling performance and reduce the maximum stress generated in the flexible lead without changing the space provided for the flexible lead, thereby improving strength and reliability.

[0013] Solutions to Problems

[0014] The rotating electrical machine disclosed in the present application is characterized by comprising:

[0015] a retaining ring engaged with the rotor to retain the rotor coil; and

[0016] interpole jumper wires, each comprising a flexible lead wire formed by laminating conductive metal plates and a metal wire connected to the flexible lead wire, electrically connecting the excitation magnetic poles of the rotor.

[0017] When the radial configuration position of the metal plate of the flexible lead is divided into two parts into an inner layer side and an outer layer side, the metal plate is divided into two parts into an inner layer side and an outer layer side only when the total number of stacked blocks of the metal plate is an odd number, except for a metal plate configured in the center in the radial direction, and the average value of the plate thickness of each metal plate configured on the inner layer side is smaller than the average value of the plate thickness of each metal plate configured on the outer layer side.

[0018] Effects of the Invention

[0019] According to the rotating electrical machine disclosed in the present application, while maintaining conventional cooling performance, the maximum stress generated in the flexible lead can be reduced without changing the space provided for the flexible lead, thereby achieving improved strength and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a cross-sectional view of the generator according to the first embodiment.

[0021] Figure 2 Is used to illustrate Figure 1 A cross-sectional view of the structure of the rotor end.

[0022] Figure 3 yes Figure 2An enlarged schematic diagram of the axial cross section of the rotor end.

[0023] Figure 4 is with Figure 2 An enlarged view of a portion (part B) of a surface perpendicular to the axis of the rotor end.

[0024] Figure 5 It is a diagram for explaining the deformation state of the flexible lead.

[0025] Figure 6 This is a front view of the flexible lead according to the first embodiment.

[0026] Figure 7 This is a front view of the flexible lead according to the second embodiment.

[0027] Figure 8 This is a front view of a flexible lead according to a third embodiment.

[0028] Figure 9 This is a front view of a flexible lead according to a fourth embodiment. DETAILED DESCRIPTION

[0029] The present application relates to a rotating electrical machine (eg, a turbine generator) including inter-pole jumper wires electrically connecting poles of a field winding. Hereinafter, embodiments of the rotating electrical machine will be described using the accompanying drawings.

[0030] Implementation method 1.

[0031] Figure 1 : is a cross-sectional view showing the overall structure of the generator according to Embodiment 1. Figure 1 In the figure, rotor 1 includes a rotor shaft 2 and a rotor body 3 mounted on rotor shaft 2. Rotor body 3 includes a rotor core 4, multiple rotor coils (not shown), and a pair of retaining rings 5. Rotor core 4 is provided with multiple rotor slots (not shown). Rotor coils are mounted in these rotor slots. Retaining rings 5 surround both ends of rotor core 4 and retain the rotor coils.

[0032] Here, the rotor 1 is electromagnetized by flowing an excitation current through the rotor coil, and is rotated by a prime mover connected to the rotor shaft 2. Thus, power generation is generated by extracting an output current flowing through the stator coil.

[0033] The rotor shaft 2 is rotatably supported by the frame 6. A pair of ventilation fans 7 are provided on the rotor shaft 2. The ventilation fans 7 are arranged at both axial ends of the rotor body 3 so as to face the retaining rings 5 and rotate integrally with the rotor shaft 2.

[0034] Furthermore, a stator 8 is provided inside the frame 6. The stator 8 includes a cylindrical stator core 9 and a plurality of stator coils 10 provided on the stator core 9. The stator 8 is arranged so as to surround the rotor core 4. Here, the inner peripheral surface of the stator 8 faces the outer peripheral surface of the rotor 1.

[0035] A cooling gas 11 is enclosed within the housing 6. For example, hydrogen or air can be used as the cooling gas 11. A gas cooler 12 is provided radially outside the stator 8 within the housing 6. As the rotor 1 rotates, the blower fan 7 rotates, and the cooling gas 11 circulates within the housing 6. This cools various components within the housing 6.

[0036] exist Figure 1 In the rotor radial ventilation type cooling method shown, cooling gas 11 is blown out by blower fan 7 and reaches a high temperature by passing through rotor body 3 and stator 8. It then passes through gas cooler 12 to a low temperature and returns to blower fan 7.

[0037] Figure 2 (a) is a cross-sectional view showing the structure of the rotor end portion of the generator according to the first embodiment. Figure 2 (b) is the Figure 2 (a) AA cross-sectional view. In addition, Figure 3 It is shown enlarged Figure 2 (a) Schematic diagram. Figure 3 As shown, a retaining ring is thermally mounted on the rotor shaft 2. Figure 2 (a) Figure 3 As shown, an end ring 16 is embedded in the outer end of the retaining ring 5 to prevent deformation of the outer side of the retaining ring 5. Furthermore, a rotor coil 15, an interpole jumper 13, and an insulating block 14 are arranged on the inner diameter side of the retaining ring 5. The interpole jumper 13 is attached to the inner diameter side of the outer side of the retaining ring 5 at the rotor end. This interpole jumper 13 serves to electrically connect the rotor poles. The rotor has two or four poles. The retaining ring 5 and the interpole jumper 13 are insulated by the insulating block 14. In the case of a turbine generator (hereinafter simply referred to as a generator), the generator's rotor shaft 2 is connected to the prime mover and the exciter at its respective ends. In this case, the interpole jumper 13 is provided on the inner diameter side of the retaining ring 5 at the rotor end on the exciter side. Furthermore, for each generator, there is only one interpole jumper, and no interpole jumper is provided on the inner diameter side of the retaining ring on the prime mover side.

[0038] Figure 4 This is an enlarged cross-sectional view of the rotor end of the generator according to the first embodiment as viewed from the axial direction, which is the same as that described above. Figure 2(b) is an enlarged view of a portion B surrounded by a dotted line. The inter-pole bridge wire 13 is annular and is arranged at the inter-pole center 1a of the rotor (the above Figure 2 (b) The area within the B portion surrounded by the dotted line is relative to Figure 4 The interpole centerline shown in the figure forms a line-symmetrical region (the range indicated by the length L enclosed by the two dashed lines in the figure, and includes a portion of the metal wire described below on both sides of the interpole centerline), and includes flexible lead wires 17 and metal wire 13a on the inner circumference of the rotor shaft. As described above, since flexible lead wires 17 are included within the interpole center portion 1a, the interpole jumper wire has flexible lead wires at two locations on the circumference.

[0039] Here, the flexible lead 17 is constructed by laminating multiple copper plates, each of which is conductive and curved, convex toward the outer diameter of the rotor. For example, tough pitch copper can be used as the copper plate. Meanwhile, the metal wire 13a is not a laminated structure but rather a single conductive wire made of the same material.

[0040] Furthermore, the material of the flexible lead is not limited to copper alloys such as tough pitch copper, and any material may be used as long as it has electrical conductivity.

[0041] The shape of the curved portion of the flexible lead 17 is approximately bilaterally symmetrical about the inter-electrode centerline (hereinafter referred to as the shape center portion 17a. This will be described in detail later). Radially adjacent layers of the flexible lead 17 abut against each other, allowing for sliding and separation at the abutment surfaces. Furthermore, both ends of the flexible lead 17 are secured to the metal wire 13a by soldering or welding. This is to prevent stress during manufacturing.

[0042] Furthermore, although the flexible leads are described above as being present in two locations, they may be present in one location.

[0043] Here, as shown in the figure, the insulating block 14 is in contact with the outer diameter side of the metal wire 13a and the flexible lead 17 of the inter-pole jumper. The outer diameter side of the insulating block 14 is covered by the annular retaining ring 5 that is heat-fitted to the end of the rotor. There are multiple insulating blocks 14 arranged along the circumferential direction. Due to the centrifugal force during rotation, the annular radius of the retaining ring 5 mentioned above expands. Along with this, the multiple insulating blocks 14 arranged along the circumferential direction between the retaining ring 5 and the inter-pole jumper 13 move toward the outer diameter side. At this time, the annular radius of the inter-pole jumper 13 expands along the inner diameter surface of the insulating block 14, but the flexible lead 17 with flexibility absorbs the circumferential extension of the metal wire 13a.

[0044] Figure 5This figure illustrates the deformation of a flexible lead. As shown in the figure, when the flexible lead is constructed by laminating copper plates of uniform thickness, the two ends of the flexible lead displace δ in the circumferential direction as shown in the figure. Consequently, a bending moment M is generated in the convex center portion 17a of each layer of the flexible lead, which includes the interpole centerline (in the figure, this is the region indicated by the angle θ enclosed by two dotted lines. Within this region, the curvature of each layer has the same sign. The curvature referred to here refers to the signed curvature, and the same applies hereinafter). This bending moment M generates tensile bending stress on the inner diameter side and compressive bending stress on the outer diameter side at the apex of each layer of the flexible lead (including the interpole centerline, or the region near the interpole centerline, and the same applies hereinafter). As a result, the innermost layer, with the greatest curvature, experiences the greatest stress at the apex of all the layers of the flexible lead.

[0045] Figure 6 This is a front view showing an example of the structure of flexible lead 17 according to Embodiment 1. In flexible lead 17 according to Embodiment 1, when the inner and outer layers are divided by half the total number of stacked blocks, the average thickness of the inner layer is smaller than that of the outer layer.

[0046] Furthermore, when the total number of laminated blocks of the flexible lead is an odd number, excluding the central layer, the layers radially inward of the central layer are designated as inner layers, and the layers radially outward of the central layer are designated as outer layers, and the average values of the respective thicknesses are compared. In this case, the number of layers constituting the flexible lead 17 is two or more.

[0047] Here, the plate thickness of the layers constituting the flexible lead 17 is two or more. In addition, the plate thickness of the entire flexible lead is the same in the circumferential direction. In addition, the axial plate width of the flexible lead 17 is the same as that of the conventional flexible lead, and the conductor cross-sectional area is also the same as that of the conventional flexible lead. A rotor shaft (not shown) is arranged on the inner diameter side of the inter-pole jumper 13 (composed of the metal wire 13a and the flexible lead 17). A gap is provided between the inter-pole jumper 13 and the rotor shaft. A gap is also provided between the center portion of the shape of the flexible lead 17 and the rotor shaft. Furthermore, during the operation of the rotating electrical machine, a ventilation fan is used to transport cooling gas to the gap between the inter-pole jumper 13 and the rotor shaft from the outside of the machine to the inside of the machine.

[0048] In such a generator, the cooling gas effect generated by ventilation can maintain conventional cooling performance, and the maximum stress generated in the flexible leads can be reduced compared to conventional methods without changing the space provided for the flexible leads, thereby improving strength and reliability.

[0049] Implementation method 2.

[0050] Figure 7 This is a front view showing an example of the structure of a flexible lead 17 of a generator according to Embodiment 2. As shown, the flexible lead 17 in Embodiment 2 gradually becomes thinner from the outer layer side toward the inner layer side. Here, the number of layers comprising flexible lead 17 is two or more. Furthermore, the types of thickness of the layers comprising flexible lead 17 are the same as the total number of stacked blocks. Furthermore, the overall thickness of the flexible lead is uniform in the circumferential direction. Other structures are the same as those in Embodiment 1. Furthermore, the axial width of flexible lead 17 is the same as that of conventional flexible leads, and the conductor cross-sectional area is also the same as that of conventional flexible leads.

[0051] A gap is provided between the interpole jumper wire 13 and the rotor shaft. Similarly, a gap is provided between the convex portion of the flexible lead wire 17 and the rotor shaft. During operation of the rotating electrical machine, cooling air is supplied from the outside of the machine toward the inside by a ventilation fan into the gap between the interpole jumper wire 13 and the rotor shaft.

[0052] The flexible lead 17 is constructed by laminating multiple copper plates, each of which is conductive and curved, convex toward the outer diameter of the rotor. Tough pitch copper, for example, can be used as the copper plates. Unlike the flexible lead, the metal wire 13a is not a laminated structure but a single, integrated wire.

[0053] Furthermore, the material of the flexible lead 17 is not limited to the copper alloy such as tough pitch copper, and any material having conductivity may be used. The same applies to the material of the metal wire.

[0054] The flexible lead 17 has a curved shape with its center portion convex radially outward, as indicated by the angle θ in the figure, and is generally bilaterally symmetrical about the inter-electrode centerline. Radially adjacent layers of the flexible lead 17 abut against each other, allowing sliding and separation at the abutting surfaces.

[0055] Both ends of the flexible lead 17 are fixed to the metal wire 13a of the inter-electrode jumper 13 by soldering or welding. This is to prevent stress from being generated during the manufacturing stage.

[0056] In such a generator, the cooling gas effect generated by ventilation can maintain conventional cooling performance, and the maximum stress generated in the flexible leads can be reduced compared to conventional methods without changing the space provided for the flexible leads, thereby improving strength and reliability.

[0057] Implementation method 3.

[0058] Figure 8This is a front view showing the structure of flexible lead 17 of a generator according to Embodiment 3. In flexible lead 17 according to Embodiment 3, when the inner and outer layers are divided by half the total number of stacked blocks, a region exists at the center portion 17a of the shape where the average thickness of the inner layer is smaller than that of the outer layer. For example, the vertex portion including the inter-electrode centerline corresponds to the region.

[0059] Furthermore, when the total number of stacked flexible lead layers is an odd number, excluding the central layer, the layers radially inward relative to the central layer are designated as inner layers, and the layers radially outward relative to the central layer are designated as outer layers, and the average thickness of each layer is compared. In this case, copper plates of uniform thickness are stacked except for the shape center portion 17a. Here, the thickness of each metal plate changes continuously from the inter-electrode centerline at the shape center portion of the flexible lead toward the peripheral portions (of the shape center portion), i.e., the ends.

[0060] Furthermore, flexible lead 17 has a shape that is approximately bilaterally symmetrical about the centerline between the electrodes. Flexible lead 17 comprises two or more layers. The thickness of the plate at the apex of each layer of flexible lead 17 varies from one to another. Furthermore, the plate thickness of the entire flexible lead is uniform in the circumferential direction. The remaining structure is the same as in Embodiment 1. Furthermore, the axial plate width of flexible lead 17 is the same as that of conventional flexible leads, and the conductor cross-sectional area is also the same as that of conventional flexible leads.

[0061] In the generator of this embodiment, a gap is also provided between the interpole jumper wire 13 and the rotor shaft (not shown). Similarly, a gap is provided between the central portion 17a of the flexible lead 17 and the rotor shaft. During operation of the rotating electrical machine, cooling air is supplied from outside to inside the machine through the gap between the interpole jumper wire 13 and the rotor shaft by a ventilation fan.

[0062] Here, the flexible lead 17 is also constructed by laminating multiple copper plates, each of which is conductive and curved convexly toward the outer diameter of the rotor. Tough pitch copper, for example, can be used as the copper plate. Furthermore, a single (relatively thick) metal wire, not a laminated structure, is connected to the periphery of the flexible lead, and these two wires form the inter-pole jumper 13.

[0063] In addition, since the structure, configuration, and material of the flexible lead of the third embodiment other than those described above are the same as those of the first embodiment or the second embodiment, their description is omitted here.

[0064] In the generator configured as described above, the cooling gas effect generated by ventilation can maintain conventional cooling performance, and the maximum stress generated in the flexible leads can be reduced compared to conventional methods without changing the space provided for the flexible leads, thereby improving strength and reliability.

[0065] Implementation method 4.

[0066] Figure 9 This is a front view showing the structure of the flexible lead 17 of the generator according to the fourth embodiment. The thickness of the flexible lead 17 in the fourth embodiment gradually decreases from the outer layer side to the inner layer side at the vertex portion of the convexly curved center portion. Copper plates of uniform thickness are stacked except for the center portion of the flexible lead 17. Furthermore, the thickness of each layer of the flexible lead 17 changes continuously from the convexly curved vertex portion toward the end of the center portion. The number of layers constituting the flexible lead 17 is two or more. The type of plate thickness at the vertex portion of each layer of the flexible lead 17 is the same as the total number of stacked layers. Furthermore, the overall plate thickness of the flexible lead is the same in the circumferential direction. The remaining structure is the same as that of the first embodiment. Furthermore, the axial plate width of the flexible lead 17 is the same as that of conventional flexible leads, and the conductor cross-sectional area is also the same as that of conventional flexible leads.

[0067] A gap is provided between the interpole jumper wire 13 and the rotor shaft (not shown). Similarly, a gap is provided between the central portion 17a of the flexible lead wire 17 and the rotor shaft. During operation of the rotating electrical machine, cooling air is supplied from outside to inside the machine via a ventilation fan to the gap between the interpole jumper wire 13 and the rotor shaft.

[0068] Furthermore, radially adjacent layers of the flexible lead 17 abut against each other, allowing sliding and separation at the abutting surfaces. Both ends of the flexible lead 17 are fixed to the inter-electrode jumper 13 by brazing or welding. This is to prevent stress from being generated during the manufacturing stage.

[0069] In the generator of this embodiment, the structure and material of the flexible lead 17 other than the above-mentioned structure are the same as those of other embodiments.

[0070] In the generator configured as described above, the cooling gas effect generated by ventilation can maintain conventional cooling performance, and the maximum stress generated in the flexible leads can be reduced compared to conventional methods without changing the space provided for the flexible leads, thereby improving strength and reliability.

[0071] Here, in each of the above-mentioned embodiments, the greater the number of copper plates constituting the flexible lead, the larger the surface area for heat transfer between the current and the cooling gas per unit cross-sectional area of the conductor through which current flows, and the lower the heat generation of the flexible lead. Therefore, the reduction in the tensile strength and fatigue strength of the material caused by the temperature rise can be suppressed, and the strength reliability can be improved.

[0072] Furthermore, the thinnest layer of the flexible lead shown in each of the above-described embodiments has a thickness that is at least such that buckling does not occur due to its own weight or centrifugal force.

[0073] In the above examples, a turbine generator is described as an example of a rotating electrical machine, but the present invention is also applicable to other generators and electric motors.

[0074] This application describes various exemplary embodiments and examples, but the various features, forms, and functions described in one or more embodiments are not limited to application in specific embodiments and can be applied to the embodiments alone or in various combinations.

[0075] Therefore, numerous variations not shown in the examples are conceivable within the scope of the technology disclosed in this specification. For example, these include modifying at least one component, adding at least one component, omitting at least one component, and extracting at least one component and combining it with components from other embodiments.

[0076] Description of Reference Numerals

[0077] 1 rotor, 1a interpole center, 2 rotor shaft, 3 rotor body, 4 rotor core, 5 retaining ring, 6 frame, 7 air supply fan, 8 stator, 9 stator core, 10 stator coil, 11 cooling gas, 12 gas cooler, 13 interpole jumper wire, 13a metal wire, 14 insulating block, 15 rotor coil, 16 end ring, 17 flexible lead, 17a shape center.

Claims

1. A rotating electrical machine, characterized in that: The rotating electrical machine comprises: a retaining ring engaged with the rotor to retain the rotor coil; and interpole jumper wires, each comprising a flexible lead wire formed by laminating conductive metal plates and a metal wire connected to the flexible lead wire, electrically connecting the excitation magnetic poles of the rotor. When the radial configuration position of the metal plate of the flexible lead is divided into two parts into an inner layer side and an outer layer side, the metal plate is divided into two parts into an inner layer side and an outer layer side only when the total number of stacked blocks of the metal plate is an odd number, except for a metal plate configured in the center in the radial direction, and the average value of the plate thickness of each metal plate configured on the inner layer side is smaller than the average value of the plate thickness of each metal plate configured on the outer layer side.

2. The rotating electrical machine according to claim 1, wherein: The flexible lead has a thickness that gradually decreases from the outer layer side toward the inner layer side.

3. The rotating electrical machine according to claim 1 or 2, characterized in that: The flexible lead is constructed as follows: the overall plate thickness is the same in the axial direction at each position in the circumferential direction, and is convex toward the outer peripheral side in the central area of the interpolar center line including the excitation magnetic pole of the rotor, that is, the shape center, and has an area where the plate thickness gradually becomes thinner from the outer layer side to the inner layer side, and has an area where the plate thickness of the stacked metal plates continuously changes in the circumferential direction.

4. The rotating electrical machine according to claim 3, wherein: The metal plate is configured to have a uniform plate thickness except for the center portion of the shape.

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