Slip ring for rotor of electrically excited rotating electromechanical generator

Abstract

The invention relates to a slip ring body (2) for an electrically excited rotor of a rotating electromechanical generator (1) which can rotate about an axis (10), the slip ring body having at least one circumferential sliding contact surface (12) which is electrically conductively connected to at least one electrical interface (11) which protrudes axially from the end side of the slip ring body (2), wherein the end side of the slip ring body (2) is provided with an electrically insulating support element (4) which substantially corresponds to the cross section of the slip ring body (2), the support element axially surrounding the interface (11) and supporting it radially.

Description

Technical Field

[0001] The invention relates to a slip ring body of a rotor of an electrically excited rotating electromechanical generator, a rotating electromechanical generator and also to the use of the same in a generator of a wind power plant. Background Art

[0002] Different designs are known for rotating electromechanical generators, especially for their use as wind turbines. One design is to feed the windings of the rotor via slip rings. The current of the rotor of the wind turbine must be drawn from the windings of the rotor and connected to the slip ring body. For this purpose, a slip ring having a diameter of more than 90 mm is used. 2 A relatively large cross-section of stranded wire.

[0003] Due to the increased runaway speed of the rotor, there is now the risk that the connecting bolts of the slip ring bodies will be damaged or their anchoring will loosen due to centrifugal loads generated by the free weight of the strands. This can result in high levels of damage or failure of the generator and relatively high repair costs.

[0004] Due to the high current intensities, such litz wire cross sections can now be provided for electrical conductivity. As a result, the freely rotating masses are now relatively large and can no longer be ignored. It is known that the electrical feeder has three copper profiles and that rigid leads are provided inside the shaft, which connect the windings of the respective slip rings and the rotor via bolts and flexible copper laminated strips. The disadvantage here is that high-current feeders are expensive and also maintenance-intensive in the event of a failure of such feeders. Summary of the invention

[0005] Based on the above, the invention is based on the object of providing a slip ring body which also increases the centrifugal force loading in conjunction with a high-current rotor winding.

[0006] The stated object is achieved by a slip ring body for an electrically excited rotor of a rotating electromechanical generator which can rotate about an axis, the slip ring body having at least one circumferential sliding contact surface which is electrically conductively connected to at least one electrical interface protruding axially from the end side of the slip ring body, wherein the end side of the slip ring body is provided with an electrically insulating support element which substantially corresponds to the cross-section of the slip ring body and which axially surrounds and radially supports the interface.

[0007] According to the invention, the interface is supported on the end side of the slip ring body by means of a centrifugal force support of the support element, in particular the connecting bolt is supported against the centrifugal load of the strands fastened to the interface and against the actual centrifugal load. The support element fulfills a dual task: firstly it withstands the centrifugal load and supports the strands and the connecting bolt, and also provides electrical insulation against the slip ring body.

[0008] Advantageously, the support element forming the support ring surrounds the entire interface or the connecting bolt in an exactly matching manner and supports the connecting bolt in the axial direction via the low-tolerance matching dimensions. Therefore, from now on, the support element absorbs the centrifugal forces acting on the connecting bolt and thus relieves the interface of the slip ring body. Therefore, according to the invention, it is avoided that the connecting bolt is damaged at the sliding body or comes out of its pre-defined fixing. Another advantage is that from now on, the cost-intensive solution of high-current feed lines at the interface can be replaced by relatively cheaper litz wire conductors, because the centrifugal force loads are absorbed by the support element according to the invention.

[0009] Thus, when using slip rings according to the invention in rotating electromechanical generators, high currents can be achieved at high machine speeds in the industrial sector and in wind turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention and other advantageous embodiments of the present invention are described in detail based on the illustrated embodiments. It is shown that:

[0011] Figure 1 shows a principle longitudinal section of an electromechanical generator,

[0012] Figure 2 A three-dimensional diagram of a slip ring body is shown,

[0013] Figures 3 to 5 A partial longitudinal section through a slip ring body showing different phases. DETAILED DESCRIPTION

[0014] Figure 1 The schematic diagram shows a longitudinal section of an electromechanical generator 1 with a slip ring body 2. The slip ring body 2 and the rotor 7 are therefore fixed in a rotationally fixed manner on a shaft 9, are coaxially oriented and rotate about an axis 10 at the same rotational speed.

[0015] The winding system 8 of the rotor 7 is supplied with power via the slip ring body 2 via a brush device 3, not shown in detail. In addition, the stator 5 also has a winding system 6. The winding systems 6 and 8 form winding heads on the end sides of the stator 5 and the rotor 7, respectively. The winding systems 6, 8 are arranged in slots, not shown in detail, in the stator 5 and the rotor 7. The electrical connection between the winding system 8 of the rotor 7 and the slip ring body 2 is carried out via a litz conductor 21, which is electrically connected to an interface, in particular a connecting bolt 11. Here, the interface has one or more connecting bolts 11, which each contact an electrical phase of the slip ring body 2.

[0016] Figure 2A perspective view of a slip ring body 2 is shown, which has an axial bore 13 and has a support element 4 on the side facing the observer, from which six connecting bolts 11 protrude. The connecting bolts 11 are surrounded by the support element 4, which is designed as a supporting ring, over their axial length protruding from the end side of the slip ring body 2. The connecting bolts 11 are surrounded by an insulation 34 except for the contact points. In this case, a contact surface 14 is exposed in each case at the axial ends of the connecting bolts 11 in the region of the support element 4, so that the litz conductor 21 can be electrically contacted with the connecting bolts 11.

[0017] The slip ring body 2 is axially connected to the support element 4 and comprises an insulating element axially surrounded by end plates 25, 26 and an axial sequence of slip ring contact surfaces 12. Here, a sliding contact surface 12 is provided for each electrical phase L1, L2, L3 corresponding to the reference numerals 15, 16, 17. In this embodiment, two connecting bolts 11 are provided for each phase 15, 16, 17. The sliding contact surface 12 preferably has a wave-shaped groove 20 as viewed in the circumferential direction in order to ensure uniform carbon brush wear.

[0018] Advantageously, the support element 4, which is designed as a one-piece support ring, surrounds the entire interface 11 or the connecting bolt in an exactly matching manner and supports the connecting bolt in the radial direction via the matching dimensions with low tolerances. Therefore, from now on, the support element 4 absorbs the centrifugal forces acting on the connecting bolt during operation of the electric machine and thus relieves the interface of the slip ring body 2. It is thus now prevented that the connecting bolt is damaged on the sliding body 2 or falls out of its intended fixing.

[0019] A further advantage is that now the costly solution of a high-current feeder at the interface 11 can be replaced by a relatively cheaper solution with a litz conductor 21 , since the centrifugal loads of the interface 11 , in particular of the connecting bolt, are absorbed according to the invention by the support element 4 .

[0020] The cost-intensive high-current feed line to be replaced is understood here to mean in particular a rigid feed line made of copper profiles in the interior of the shaft which electrically connects the slip ring and the rotor winding to one another via a plurality of bolts and flexible copper laminated strips.

[0021] Figures 3 to 5 In almost identical embodiments, there is a partial longitudinal section of the slip ring body 2, wherein Figure 3 , Figure 4 and Figure 5 They are distinguished only by the contact of the respective connecting bolt 11 with its respective sliding contact surface 12. The connecting bolt 11, in particular the connecting bolt of the phase L1, reference numeral 15, is guided insulated through the other contact surface of the other phase to the end face of the slip ring body 2. This can be compared in particular Figures 3 to 5to be sure.

[0022] Between the individual sliding contact surfaces 12 of the respective phase L1 , L2 , L3 there are insulating elements 19 and 24 which are intended to prevent electrical flashovers between the phases.

[0023] Insulation elements 18 and 22 are also present, in particular between the axially outer sliding contact surfaces 12 of the phases L1 and L3 and further components, for example grounded end plates, which are intended to prevent arcing between the grounded components and the phases.

[0024] In order to extend the creepage paths between the different potentials, ribs 23 are provided on the insulating elements 18 , 19 , 24 and 22 .

[0025] The support element 4 is advantageously designed as a one-piece support ring made of electrically insulating material, which has ribs 29 on its outer circumferential surface 27 and / or its inner circumferential surface 28 for enlarging the creepage path. The diameter 31 of the entire support element corresponds approximately to the diameter of the slip ring body 2. The radial extension 29 corresponds to 1.5 to 5 times the diameter 33 of the connecting bolt 11 of the support ring, depending on the requirements for centrifugal force compensation, as can be seen, for example, from Figure 5 The axial thickness 32 of the support element 4 is also dependent on the centrifugal load and corresponds to 0.5 to 3 times the diameter 33 of the connecting bolt 11 .

[0026] Advantageously, the support element 4 has an axial thickness 32 that remains constant. However, it is also possible that the one-piece support element 4 is already provided with an axial projection during production, in particular in the region around the connecting bolt 11, in order to achieve improved radial support. The axial projection surrounds the connecting bolt 11 in this case in the form of a ring with a thickness that corresponds approximately to the diameter of the connecting bolt 11.

[0027] Furthermore, the outer and inner circumferential surfaces 27, 28 of the support element 4 are oriented substantially parallel. The radial rib height of the ribs provided on the outer and inner circumferential surfaces 27, 28 is the same.

[0028] In another form of the concept of the invention, the outer and / or inner circumferential surfaces 27, 28 of the support element 4 are conically designed. That is, the outer circumferential surface 27 in its axial extension begins at the end side of the slip ring body 2 toward the axis 10. In addition or alternatively, the inner circumferential surface 28 in its axial extension begins at the end side of the slip ring body 2 and extends away from the axis 10.

[0029] Thus, when viewed in the circumferential direction, there is a trapezoidal cross section of the support element 4, ie of the support ring. This is achieved in that the basic body of the support element 4, in particular its basic circumferential surface provided with the ribs 29, is designed accordingly and / or - as long as, as in Figures 2 to 5 As shown in FIG. 2 , a plurality of ribs 29 are shown - the rib height of the circumferential ribs 29 is varied. Thus, for example, the ribs 29 at the end face of the sliding ring body 2 on the support element 4 have a greater rib height than the ribs arranged further away from the end face.

[0030] In other words, the rib height of the individual ribs extending in the circumferential direction decreases with further axial extension.

[0031] The simple and effective construction of the slip ring body 2 allows reliable and low-maintenance operation of such a rotating electrical machine, in particular when it is used as a generator in a separation plant either offshore or onshore.

Claims

1. A slip ring body (2) for an electrically excited rotor of a rotating electromechanical generator (1) which can rotate about an axis (10), the slip ring body having at least one circumferential sliding contact surface (12) which is electrically conductively connected to at least one electrical connecting bolt (11) which protrudes axially from the end side of the slip ring body (2), wherein the end side of the slip ring body (2) is provided with an electrically insulating support element (4) which substantially corresponds to the cross section of the slip ring body (2), the support element axially surrounds all the connecting bolts (11) and radially supports them, wherein the slip ring body (2) is axially connected to the support element (4), the slip ring body comprising an insulating element axially surrounded by end plates (25, 26) and an axial sequence of slip ring contact surfaces (12), wherein the connecting bolt (11) is surrounded by an insulating part except for the contact surface, wherein the support element (4) is designed as a one-piece support ring and is mounted on the outer side of the end plate.

2. The slip ring body (2) according to claim 1, characterized in that: The support element (4) has means for enlarging the creepage path.

3. The slip ring body (2) according to claim 2, characterized in that: The support element (4) has means for enlarging the creepage path on a radially outer circumferential surface (27) of the support element.

4. The slip ring body (2) according to claim 2 or 3, characterized in that: The support element (4) has circumferential ribs (29) for the purpose of enlarging the creepage path.

5. A rotating electromechanical generator (1) having an electrically excited rotor (7), in the axial extension of which a slip ring body (2) according to any one of the preceding claims is arranged, rotating about the same axis (10) as the rotor (7).

6. A wind turbine having a rotating electromechanical generator (1) according to claim 5.

7. A wind power plant comprising the wind power generator according to claim 6.

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