Axial slip ring system and generator set

Abstract

The axial slip ring system comprises a slip ring, a collecting ring and an electric brush assembly, the slip ring is sleeved with the collecting ring, the collecting ring is used for being connected with an excitation cable, the electric brush assembly is arranged on the collecting ring, the electric brush assembly comprises an electric brush, and the electric brush abuts against the end face of the slip ring in the axial direction of the slip ring. According to the axial slip ring system and the generator set, the electric brush is arranged in the axial direction of the slip ring, the contact area of the electric brush and the slip ring is large, and sliding fit of the electric brush and the slip ring is stable, so that the temperature of the slip ring and the electric brush during operation can be effectively reduced, and normal operation of the generator set is ensured.

Description

Technical Field

[0001] This invention relates to the field of generator technology, and in particular to an axial slip ring system and generator set. Background Technology

[0002] For large hydro-generator units, whether vertical or horizontal, excitation voltage is typically obtained from the generator terminals using a self-excited system. This excitation voltage is rectified by thyristors and then transmitted to the positive and negative poles of the generator rotor via excitation cables. Power transmission between the excitation cables and the generator rotor relies on a carbon brush and slip ring system. In related technologies, the carbon brush and slip ring system includes slip rings, carbon brushes, etc. The carbon brushes abut against the outer circumference of the slip rings. The power transmission path is: excitation cable → slip rings → carbon brushes → slip rings → rotor leads → rotor windings.

[0003] The carbon brush slip ring system has some drawbacks in application: 1) Due to the large radius of curvature of the outer circumference of the slip ring, even if the new carbon brush has been polished, it cannot completely fit the outer circumference of the slip ring. This will result in insufficient current conduction area, leading to high local current density and thus causing the carbon brush temperature to rise; 2) The carbon brush is very sensitive to the roundness deviation of the slip ring, the unevenness of the surface area of ​​the outer circumference, and the vibration of the main shaft. In particular, it is constrained by hydraulic imbalance factors. That is, the stress generated by the vibration of the main shaft during operation and transmitted to the carbon brush must be considered. If the turning effect is not good, some carbon brushes will wear unevenly, and some carbon brushes will have poor contact, resulting in increased contact resistance and thus causing abnormal carbon brush temperature. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, in a first aspect, embodiments of the present invention provide an axial slip ring system, the axial slip ring system comprising: a slip ring; a slip ring sleeved on the slip ring, the slip ring being used for connection with an excitation cable; and a brush assembly disposed on the slip ring, the brush assembly comprising brushes, the brushes abutting against the end face of the slip ring along the axial direction of the slip ring.

[0006] In this embodiment of the invention, the axial slip ring system places the brush on the axial direction of the slip ring, meaning the brush mates with the end face of the slip ring. This eliminates the need for brush grinding, allowing the brush to perfectly fit the slip ring and maintain a close contact. The large contact area and uniform current density distribution effectively prevent brush temperature rise caused by insufficient current-carrying area. Furthermore, the brush's axial placement eliminates the influence of slip ring roundness deviations, unevenness of the outer circumferential surface, and shaft vibration. When the slip ring rotates, the brush remains stationary with the slip ring, achieving a sliding fit. During this process, the brush does not experience radial runout and maintains tight contact with the slip ring, eliminating issues such as uneven wear or poor contact. Consequently, abnormal brush temperature is also avoided.

[0007] Compared to related technologies, this axial slip ring system places the brush on the axial direction of the slip ring, resulting in a large contact area between the brush and the slip ring and stable sliding fit between them. This effectively reduces the temperature of the slip ring and brush during operation, ensuring the normal operation of the generator set.

[0008] In some embodiments, the brush assembly further includes: a brush holder disposed on the slip ring; and a brush spindle electrically connected to the brush via a brush braid, wherein the brush spindle and the brush holder are detachably connected.

[0009] In some embodiments, the brush holder is provided with a mounting hole; the brush spindle is inserted into the mounting hole, and a matching groove and slide rail are provided between the side wall of the brush spindle and the inner wall of the brush holder; the groove and the slide rail extend spirally along the axial direction of the mounting hole, one of the groove and the slide rail is provided on the inner wall of the brush holder, and the other of the groove and the slide rail is provided on the side wall of the brush spindle.

[0010] In some embodiments, the brush assembly further includes a drive assembly that is drively connected to the brush spindle to drive the brush spindle to rotate about its own axis.

[0011] In some embodiments, the drive assembly includes: a brush holder; a mounting housing, wherein two meshing bevel gears are provided inside the mounting housing and the bevel gears are rotatably engaged with the mounting housing so as to be rotatable about their own axes; the two bevel gears are respectively disposed on the brush holder and the brush spindle.

[0012] In some embodiments, the axial slip ring system further includes a brush holder disposed in the mounting housing; the brush is disposed in the brush holder.

[0013] In some embodiments, the brush holder is slidably engaged with the slip ring so as to slide radially along the slip ring; a locking structure is provided between the brush holder and the slip ring, the locking structure locking or unlocking the sliding of the brush holder on the slip ring.

[0014] In some embodiments, the brush is provided with a slot that extends from the end of the brush that contacts the slip ring into the brush.

[0015] In some embodiments, the end face of the slip ring is recessed to form an annular groove, and the bottom surface of the annular groove abuts against the brush.

[0016] Secondly, embodiments of the present invention also provide a generator set, the generator set including a rotor winding and an axial slip ring system of any of the above embodiments; the positive and negative poles of the rotor winding are provided with the axial slip ring system; the slip ring is disposed on the rotor shaft of the rotor winding. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the axial slip ring system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the brush assembly according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of the brush assembly according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the brush spindle according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the brush holder structure according to an embodiment of the present invention; Figure 6 This is a cross-sectional view of the brush holder according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of the brush according to an embodiment of the present invention.

[0018] Figure label: 100. Slip ring; 110. Annular groove; 200. Slip ring; 300. Brush assembly; 310. Brush; 320. Brush holder; 330. Brush spindle; 340. Brush braid; 350. Slide groove; 360. Slide rail; 370. Drive assembly; 380. Brush holder; 390. Constant force spring; 311. Slot; 321. Mounting hole; 371. Brush holder; 372. Mounting housing; 373. Bevel gear; 374. Bearing. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] like Figure 1 As shown, the axial slip ring system of this invention includes: a slip ring 100, a slip ring 200, and a brush assembly 300. The slip ring 200 is sleeved on the slip ring 100 and is used to connect to the excitation cable. The brush assembly 300 is disposed on the slip ring 200 and includes a brush 310. The brush 310 abuts against the end face of the slip ring 100 along the axial direction of the slip ring 100.

[0021] In this embodiment of the invention, the axial slip ring system places the brush 310 on the axial direction of the slip ring 100, meaning the brush 310 mates with the end face of the slip ring 100. This eliminates the need for grinding the brush 310, allowing it to perfectly fit the slip ring 100. The large contact area and uniform current density distribution effectively prevent the brush 310 from overheating due to insufficient current-carrying area. Furthermore, the brush 310's axial position on the slip ring 100 prevents it from being affected by roundness deviations, unevenness of the outer circumferential surface, or shaft vibration. When the slip ring 100 rotates, the brush 310 remains stationary with the slip ring 200, achieving a sliding fit with the slip ring 100. During this process, the brush 310 does not experience radial runout and maintains tight contact with the slip ring 100, eliminating issues such as uneven wear or poor contact. Consequently, abnormal brush 310 temperature is also avoided.

[0022] Compared with related technologies, this axial slip ring system places the brush 310 on the axial direction of the slip ring 100, resulting in a large contact area between the brush 310 and the slip ring 100, and a stable sliding fit between the brush 310 and the slip ring 100. This effectively reduces the operating temperature of the slip ring 100 and the brush 310, ensuring the normal operation of the generator set.

[0023] It should be added here that the slip ring 200 is equipped with multiple brush assemblies 300 that cooperate with the slip ring 100. The multiple brush assemblies 300 can increase the current conduction capacity and conductivity reliability.

[0024] The following combination Figures 1 to 7 The structure and shape of the axial slip ring system according to an embodiment of the present invention will be described in detail below: In some embodiments, reference is made to Figure 2 and Figure 3The brush assembly 300 also includes a brush holder 320 and a brush spindle 330. The brush holder 320 is located on the slip ring 200, and the brush spindle 330 is electrically connected to the brush 310 through a brush braid 340. The brush spindle 330 and the brush holder 320 are detachably connected.

[0025] The brush spindle 330 and the brush holder 320 are detachably connected, that is, the brush assembly 300 and the slip ring 200 are detachably connected. With this design, the brush assembly 300 and the slip ring 200 can be disassembled and assembled, which facilitates the replacement of the brush 310.

[0026] During operation, the slip ring 100 rotates, the brush assembly 300 remains stationary with the slip ring 200, and the brush 310 slides in contact with the slip ring 100. The current flowing through the excitation cable is transmitted through the slip ring 200 → brush holder 320 → brush spindle 330 → brush braid 340 → brush 310 → slip ring 100 → rotor lead → rotor winding, thus completing the transmission of current from the stationary body to the rotating body.

[0027] In some embodiments, reference is made to Figures 3 to 6 The brush holder 320 is provided with a mounting hole 321; the brush spindle 330 is inserted into the mounting hole 321, and the side wall of the brush spindle 330 and the inner wall of the brush holder 320 are provided with a matching groove 350 and a slide rail 360; the groove 350 and the slide rail 360 extend spirally along the axial direction of the mounting hole 321, one of the groove 350 and the slide rail 360 is provided on the inner wall of the brush holder 320, and the other of the groove 350 and the slide rail 360 is provided on the side wall of the brush spindle 330.

[0028] Through the cooperation of the slide groove 350 and the slide rail 360, the brush spindle 330 can be screwed into or out of the mounting hole 321, correspondingly realizing the connection and disassembly with the brush holder 320. The design of the slide groove 350 and the slide rail 360 ensures that the brush spindle 330 will not separate from the brush holder 320 when the generator set is running, which also ensures that the brush assembly 300 will not fall off the slip ring 200 under operating conditions. This design also makes the brush spindle 330 and the brush holder 320 easy to assemble and disassemble, and improves maintenance efficiency.

[0029] Optionally, such as Figures 4 to 6 As shown, the groove 350 is provided on the brush spindle 330, and the slide rail 360 is provided on the brush seat 320. There are multiple grooves 350, such as four. The four grooves 350 are evenly distributed along the circumference of the brush spindle 330. Correspondingly, there are also four slide rails 360. The four slide rails 360 are evenly distributed along the circumference of the mounting hole 321.

[0030] In some embodiments, reference is made to Figure 4The brush spindle 330 includes an upper connecting section and a lower connecting section. The lower connecting section is cylindrical, and a groove 350 is formed on the side of the lower connecting section. Optionally, during machining, the machine tool cuts at a full stroke of 90 degrees for the groove 350 and the slide rail 360. In this way, the brush spindle 330 rotates 90° around its own axis, and the lower connecting section will be completely screwed into the mounting hole 321, reaching the bottom dead point of the mounting hole 321, or completely screwed out of the mounting hole 321, disengaging from the top disengagement point of the mounting hole 321.

[0031] In some embodiments, reference is made to Figure 2 and Figure 3 The brush assembly 300 also includes a drive assembly 370, which is connected to the brush spindle 330 to drive the brush spindle 330 to rotate about its own axis.

[0032] The drive assembly 370 can drive the brush spindle 330 to rotate around its own axis, thereby causing the brush spindle 330 to be screwed into or out of the mounting hole 321, realizing the connection or separation of the brush spindle 330 and the brush holder 320, and thus realizing the assembly and disassembly of the brush assembly 300 on the slip ring 200.

[0033] For details, please refer to Figure 3 The drive assembly 370 includes a brush holder 371 and a mounting housing 372. The mounting housing 372 is provided with two meshing bevel gears 373, and the bevel gears 373 and the mounting housing 372 are rotatably engaged by bearings 374 so that they can rotate around their own axes. The two bevel gears 373 are respectively located on the brush holder 371 and the upper connecting section.

[0034] When the brush holder 371 rotates 90°, the brush spindle 330 rotates 90° accordingly via the transmission of two bevel gears 373, allowing the lower connecting section to be fully screwed into or out of the mounting hole 321. The brush holder 371 is made of phenolic resin, whose high-strength insulation properties ensure the safety of the operator.

[0035] In some embodiments, reference is made to Figure 2 and Figure 3 The axial slip ring system also includes a brush box 380, which is located in the mounting housing 372; and a brush 310 is located in the brush box 380.

[0036] Specifically, with Figure 3 For example, the right end of the brush box 380 is fixed to the mounting housing 372, and the left end has a receiving cavity. The brush 310 is located in the receiving cavity, and the brush 310 abuts against the end face of the slip ring 100 under the pressure of the constant force spring 390. It should be noted here that the selection of the type of constant force spring 390 and the method of setting it can be referred to the existing technology, and will not be elaborated here.

[0037] In some embodiments, reference is made to Figure 1The brush holder 320 is slidably engaged with the slip ring 200, allowing it to slide radially along the slip ring 200. A locking structure is provided between the brush holder 320 and the slip ring 200 to lock or unlock the sliding of the brush holder 320 on the slip ring 200. This design allows for radial adjustment of the position of the brush holder 320 along the slip ring 200, thereby indirectly adjusting the contact position between the brush 310 and the slip ring 100, ensuring full contact between the brush 310 and the slip ring 100.

[0038] Optionally, the assembly structure includes bolts and nuts, with the brush holder 320 bolted to the slip ring 200. This design facilitates the disassembly and assembly of the brush holder 320, thereby facilitating the adjustment of the position of the brush 310.

[0039] More preferably, refer to Figure 1 The end face of the slip ring 100 is recessed to form an annular groove 110, and the bottom groove surface of the annular groove 110 abuts against the brush 310. Here, the annular groove 110 is the sliding track of the brush 310, which separates the brush 310 from the bolt on the slip ring 100 (the bolt is used to fix the slip ring 100 to the rotor shaft), thus avoiding interference between the bolt and the brush 310 when the slip ring 100 rotates.

[0040] In addition, when the slip ring 100 rotates at high speed, it will generate a strong centrifugal force. This force will be along the tangential direction of the ring groove 110, which can quickly throw the powder generated by the wear of the brush 310 to the outer edge of the slip ring 100. In this way, the probability of powder accumulating, burning, and caking on the surface of the slip ring 100 is reduced, as well as the risk of short circuit between the positive and negative poles of the slip ring 100.

[0041] More preferably, refer to Figure 7 The brush 310 is provided with a slot 311, which extends from the end of the brush 310 that contacts the slip ring 100 into the brush 310.

[0042] Combination Figure 1 As shown, during application, the high-speed rotating slip ring 100 end face will "drag" the air at the edge of the contact area into the narrow gap between the brush 310 and the slip ring 100 through the viscous force of the air. This is viscous traction. The presence of the slot 311 makes the gap between the brush 310 and the slip ring 100 a converging wedge. The dragged air will flow from the area with a larger gap (narrow gap) to the area with a smaller gap (slot 311). According to Bernoulli's principle and Reynolds equation in fluid mechanics, in order to satisfy the conservation of flow, the air velocity will increase in these converging regions, but its pressure will rise sharply. The pressure generated in the high-pressure region is sufficient to "push up" the brush 310, causing the brush 310 to separate from the slip ring 100, thereby forming an extremely thin air film between the brush 310 and the slip ring 100. This is the pressure wedge effect.

[0043] As mentioned above, the presence of an air film enables fluid lubrication, meaning that air film lubrication replaces hard friction between the brush 310 and the slip ring 100. This reduces the coefficient of friction between the brush 310 and the slip ring 100. In related technologies, where the brush is also rotating at high speed, the radially arranged carbon brush is affected by the swing during unit operation, causing direct shearing between the carbon brush and the slip ring 100. The tangential pressure is extremely high (>30kPa), which accelerates the wear of the carbon brush. However, in this embodiment, the pressure can be reduced to 18-22kPa, reducing the wear of the brush 310 by more than 70%. This significantly improves the service life of the brush 310 and reduces the workload of maintenance personnel.

[0044] Continuing from the above, the friction between the brush 310 and the slip ring 100 is reduced, and the powder formed by the wear of the brush 310 is less likely to accumulate on the end face of the slip ring 100, that is, no "carbon deposit" will be generated on the end face of the slip ring 100. As a result, the heat generated by the brush 310 naturally decreases and the temperature is within the normal range.

[0045] This invention also proposes a generator set, which includes a rotor winding and an axial slip ring system of any of the above embodiments; the positive and negative poles of the rotor winding are provided with an axial slip ring system; the slip ring 100 is disposed on the rotor shaft of the rotor winding.

[0046] Specifically, the axial slip ring system is located at the non-drive end of the generator set. The slip ring 100 is fixed to the rotor shaft by insulating bolts. The slip rings 200 of the two axial slip ring systems are an integral structure and are fixed on the fixed bracket of the generator set. Positive and negative excitation cables are connected to the slip rings 200.

[0047] In application, the positive (+) output terminal of the DC excitation power supply (such as an exciter or rectifier cabinet) is connected to the collector ring 200 of one of the axial slip ring systems via a positive excitation cable. Then, the current is sequentially delivered to the rotor leads through the brush holder 320, brush spindle 330, brush braid 340, brush 310 and slip ring 100 of the axial slip ring system, and then to the rotor winding. After the current flows in the rotor winding and establishes a magnetic field, it is conducted out through another axial slip ring system connected to the negative terminal of the rotor winding, and returns to the negative (-) input terminal of the DC excitation power supply via the negative excitation cable, forming a complete DC excitation circuit.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0052] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0053] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An axial slip ring system, characterized in that, include: Slip ring (100); A slip ring (200) is sleeved on the slip ring (100) and is used to connect to the excitation cable; A brush assembly (300) is disposed on the slip ring (200). The brush assembly (300) includes a brush (310) which abuts against the end face of the slip ring (100) along the axial direction of the slip ring (100).

2. The axial slip ring system according to claim 1, characterized in that, The brush assembly (300) also includes: Brush holder (320), the brush holder (320) is disposed on the slip ring (200); The brush spindle (330) is electrically connected to the electric brush (310) via a brush braid (340), and the brush spindle (330) is detachably connected to the brush holder (320).

3. The axial slip ring system according to claim 2, characterized in that, The brush holder (320) is provided with mounting holes (321); The brush spindle (330) is used to be inserted into the mounting hole (321), and the side wall of the brush spindle (330) and the inner wall of the brush seat (320) are provided with a matching groove (350) and a slide rail (360). The groove (350) and the slide rail (360) extend spirally along the axial direction of the mounting hole (321). One of the groove (350) and the slide rail (360) is located on the inner wall of the brush holder (320), and the other of the groove (350) and the slide rail (360) is located on the side wall of the brush spindle (330).

4. The axial slip ring system according to claim 3, characterized in that, The brush assembly (300) further includes a drive assembly (370) which is tractively connected to the brush spindle (330) to drive the brush spindle (330) to rotate about its own axis.

5. The axial slip ring system according to claim 4, characterized in that, The drive component (370) includes: Brush grip (371); The mounting housing (372) has two meshing bevel gears (373) inside, and the bevel gears (373) are rotatably engaged with the mounting housing (372) so as to be able to rotate around their own axis; The two bevel gears (373) are respectively disposed on the brush holder (371) and the brush spindle (330).

6. The axial slip ring system according to claim 5, characterized in that, The axial slip ring system also includes a brush holder (380), which is disposed in the mounting housing (372); The brush (310) is disposed in the brush box (380).

7. The axial slip ring system according to claim 2, characterized in that, The brush holder (320) is slidably engaged with the slip ring (200) so that it can slide along the radial direction of the slip ring (200); A locking structure is provided between the brush holder (320) and the collector ring (200), which locks or unlocks the sliding of the brush holder (320) on the collector ring (200).

8. The axial slip ring system according to claim 1, characterized in that, The brush (310) is provided with a slot (311), which extends from the end of the brush (310) that contacts the slip ring (100) into the brush (310).

9. The axial slip ring system according to claim 1, characterized in that, The end face of the slip ring (100) is recessed to form an annular groove (110), and the bottom groove surface of the annular groove (110) abuts against the brush (310).

10. A generator set, characterized in that, Includes rotor windings and an axial slip ring system as described in any one of claims 1 to 9; The axial slip ring system is provided at both the positive and negative poles of the rotor winding; The slip ring (100) is disposed on the rotor shaft of the rotor winding.

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