DYNAMOELECTRIC MACHINE HAVING COOLING OF THE SLIP RING SYSTEM

Abstract

A dynamoelectric machine includes a shaft, a rotor arranged fixedly on the shaft for conjoint rotation, and a slip ring system enabling a rotor winding system to be contacted electrically and including a slip ring body having slip rings arranged spaced-apart axially behind one another and assigned to an electrical phase. The slip ring body is connected fixedly to the shaft for conjoint rotation and has between an inner side thereof and the shaft a section which forms an axially open cavity on both skies. In a region of the slip ring system, the shaft is hollow with a hollow shaft portion assigned to the slip ring system for routing feed lines to the rotor winding system. Recesses are provided on the cavity axially on an inside and axially on an outside for introducing a cooling medium flow axially into the cavity and discharge thereof into an outlet region.

Claims

1.-6. (canceled)

7. A dynamoelectric machine, in particular a double-fed asynchronous machine, said dynamoelectric machine comprising: a stator; a shaft; a rotor interacting with the stator, said rotor being arranged fixedly on the shaft for conjoint rotation and comprising a winding system; and a slip ring system designed to enable the winding system of the rotor to be contacted electrically and comprising a slip ring body including slip rings which are arranged axially behind one another and spaced apart from one another in an insulated manner and which are assigned to an electrical phase, said slip ring body being connected fixedly to the shaft for conjoint rotation and having between an inner side of the slip ring body and the shaft at least one section designed to form a cavity which is open axially on both sides and is designed as a circumferential cutout so that the slip ring body lies at least on two circumferentially running boundary elements which are spaced apart axially from one another and which are connected through shrink fit in one piece with an inside of the slip ring body and/or of the shaft, wherein the shaft is designed at least in a region of the slip ring system as a hollow shaft which has a hollow shaft portion assigned to the slip ring system for routing feed lines to the winding system of the rotor, and wherein axial recesses are provided on the cavity axially on an inside and axially on an outside for enabling introduction of a cooling medium flow axially into the cavity and discharge of the cooling medium flow into an outlet region, with first ones of the axial recesses being formed about an entire circumference of one of the two circumferentially running boundary elements for introduction of the cooling medium flow, and with second ones of the axial recesses being formed about an entire circumference of the other one of the two circumferentially running boundary elements for discharge of the cooling medium flow.

8. The dynamoelectric machine of claim 7, wherein the slip ring system comprises an electrical energy transmission unit in the form of a brush unit which includes one or more brushes assigned to a corresponding one of the slip rings per electrical phase, said brush unit comprising a brush holder for arrangement of the one or more brushes.

9.-10. (canceled)

11. The dynamoelectric machine of claim 7, wherein the boundary elements are designed as rings or webs.

12. The dynamoelectric machine of claim 7, wherein in a region of the cavity, the shaft has a reduced diameter portion over a predefined axial length and/or the slip ring body has a widened diameter portion.

13. The dynamoelectric machine of claim 7, wherein the cavity is designed to form a labyrinth-like and/or meandering structure in the cavity so as to increase a dwell time of the cooling medium flow.

14. The dynamoelectric machine of claim 7, wherein the cooling medium flow is an air flow.

15. The dynamoelectric machine of claim 14, further comprising an external fan or an integral fan designed to generate the air flow.

16. A wind power plant, comprising a dynamoelectric machine, said dynamoelectric machine comprising a stator, a shaft, a rotor interacting with the stator, said rotor being arranged fixedly on the shaft for conjoint rotation and comprising a winding system, and a slip ring system designed to enable the winding system of the rotor to be contacted electrically and comprising a slip ring body including slip rings which are arranged axially behind one another and spaced apart from one another in an insulated manner and which are assigned to an electrical phase, said slip ring body being connected fixedly to the shaft for conjoint rotation and having between an inner side of the slip ring body and the shaft at least one section designed to form a cavity which is open axially on both sides and is designed as a circumferential cutout so that the slip ring body lies at least on two circumferentially running boundary elements which are spaced apart axially from one another and which are connected through shrink fit in one piece with an inside of slip ring body and/or of the shaft, wherein the shaft is designed at least in a region of the slip ring system as a hollow shaft which has a hollow shaft portion assigned to the slip ring system for routing feed ones to the winding system of the rotor, and wherein axial recesses are provided on the cavity axially on an inside and axially on an outside for enabling introduction of a cooling medium flow axially into the cavity and discharge of the cooling medium flow into an outlet region, with first ones of the axial recesses being formed about an entire circumference of one of the two circumferentially running boundary elements for introduction of the cooling medium flow, and with second ones of the axial recesses being formed about an entire circumference of the other one of the two circumferentially running boundary elements for discharge of the cooling medium flow.

17. The wind power plant of claim 16, wherein the slip ring system comprises an electrical energy transmission unit in the form of a brush unit which includes one or more brushes assigned to a corresponding one of the slip rings per electrical phase, said brush unit comprising a brush holder for arrangement of the one or more brushes.

18.-19. (canceled)

20. The wind power plant of claim 16, wherein the boundary elements are designed as rings or webs.

21. The wind power plant of claim 16, wherein in a region of the cavity, the shaft has a reduced diameter portion over a predefined axial length and/or the slip ring body has a widened diameter portion.

22. The wind power plant of claim 16, wherein the cavity is designed to form a labyrinth-like and/or meandering structure in the cavity so as to increase a dwell time of the cooling medium flow.

23. The wind power plant of claim 16, wherein the cooling medium flow is an air flow.

24. The wind power plant of claim 23, wherein the dynamoelectric machine comprises an external fan or an integral fan designed to generate the air flow.

Description

[0038] The invention and further advantageous refinements of the invention will be explained in greater detail in the following text on the basis of schematically shown exemplary embodiments, in which:

[0039] FIG. 1 shows a longitudinal section of a diagrammatic machine,

[0040] FIG. 2 shows a longitudinal section of a slip ring body,

[0041] FIG. 3 shows a partial perspective illustration of a slip ring body,

[0042] FIG. 4 shows a further perspective illustration of a slip ring body,

[0043] FIG. 5 shows a longitudinal section of a slip ring system,

[0044] FIG. 6 shows a longitudinal section of a slip ring system with a schematic illustration of a cooling air flow, and

[0045] FIG. 7 shows a perspective illustration of an open slip ring system.

[0046] FIG. 1 shows a schematic longitudinal section of a dynamoelectric machine 24 and a housing 29. A stator 25 which has a winding system 26 in grooves (not shown in greater detail) of a laminated core of the stator 25 is inserted in the housing 29. Winding heads are formed by way of the winding system 26 on the end sides of the stator 25. A rotatably mounted rotor 27 with a winding system 28 is situated spaced apart from the stator 25 by way of an air gap 43, which winding system 28 likewise configures winding heads on the end sides of the rotor 27. The rotor 27 is supported via bearings 30 and bearing plates on the housing 29 of the machine 24.

[0047] A slip ring system 1 which is connected via feed lines 35 to the winding system 28 of the rotor 27 is situated in an axial extension of the dynamoelectric machine 24 for electrical excitation of the rotor 27. Here, the feed lines 35 preferably run in a hollow shaft portion of the shaft 4.

[0048] As can also be gathered from the following figures, the slip ring system 1 has a slip ring body 2 and a brush unit 14 which are accommodated in a slip ring housing 17. Here, the slip ring body 2 has slip rings 3 which are arranged axially behind one another and are in each case spaced apart axially by an insulating segment 7. A grounding ring 6 is situated on one end side of the slip ring body 2, and an insulation ring 5 is situated on the other end side of the slip ring body 2. Contact pins 8 which are contacted electrically in each case to the respectively associated slip ring 3 emerge axially on this insulation ring 5.

[0049] The brush unit 14 is positioned in the slip ring housing 17 and has one or more brushes 15 per electrical phase, that is to say per slip ring 3, which brushes 15 are assigned to the respective slip ring 3 or the grounding ring 6. The brushes 15 are arranged in each case in a brush holder 22 which also provides corresponding electrical contacting devices. Here, the brushes 15 per slip ring 3 are arranged next to one another and/or behind one another.

[0050] In its schematic longitudinal section, FIG. 2 shows a slip ring body 2, the slip rings 3 being spaced apart axially behind one another and by respective insulating segments 7. The slip rings 3 are arranged on an insulating sleeve 16 which is arranged on a supporting structure 41 or hub. The supporting structure 41 is at an identical electrical potential to the grounding ring 6. Each of the slip rings 3 is contacted electrically to one or more contact pins 8, with the result that the electrical energy which is provided on the running surface 10 of the respective slip ring 3 can be fed to the contact pin 8, in order to be conducted from there via conductors, in particular stranded conductors through the hollow shaft or hollow shaft portion to the winding system 28 of the rotor 27.

[0051] On its radially inner side which faces the shaft 4, the slip ring body 2 has an axial portion which is recessed with regard to the end portions 12 which limit it, that is to say has a greater internal radius. There are openings 21 which act as aeration bores or ventilation bores in these end portions 12. As soon as the slip ring body 2 is situated on a shaft 4 or hollow shaft, this comparatively greater internal radius produces a cavity 11 between the two end portions 12 of the supporting structure 41, that is to say the axial boundary elements of the cavity 11 which can be configured as rings or webs.

[0052] FIG. 3 shows a partial perspective illustration of a slip ring body 2 from one end side, more precisely from the machine side or bearing side 39. Here, the grounding ring 6 and its spacing from a slip ring 3 by way of an insulating segment 7 can be seen on the end side of the slip ring body 2. In this case, the running surface 10 of a slip ring 3 can also be seen, on which running surface 10 grooves 9 are situated which also permit radial aeration of the slip ring 3. Openings 13 are provided on the grounding ring 6, which openings 13 permit an inflow of air via the openings 21 of the end portions or boundary elements into the cavity 11 which results between the shaft 4 and the slip ring body 2.

[0053] FIG. 4 shows a perspective illustration of the slip ring body 3 from its other end side, the connector side 40. Contact pins 8 emerge axially from the insulation ring 5, each electrical phase or each slip ring 3 in this case being assigned two contact pins 8, This is adjoined axially by a sequence of installation segments 7 and slip rings 3. The axial sequence is ended by the grounding ring 6. The running surfaces 10 of the individual slip rings 3 have grooves 9 which are radially continuous and thus possibly permit further cooling of the slip ring 3. Furthermore, these slip rings 3 have axial openings which likewise contribute to cooling of the slip rings 3. Regardless of this or in addition to this, the insulating segments 7 are of blade-like configuration on the radially outer edge, with the result that air turbulence occurs in the case of rotation of the slip ring body 2.

[0054] The slip ring body 2 has a central opening 31, into which a shaft 4, a shaft 4 for the axial hollow shaft portion, or a hollow shaft is inserted. This shaft 4 is connected fixedly to the slip ring body 2 for conjoint rotation. Via the contact pins 8 and electrical feed lines 35 which are connected to them, the winding system 28 of the rotor 27 is then supplied electrically via a hollow shaft portion of the shaft 4 or the hollow shaft.

[0055] FIG. 5 shows a longitudinal section of the slip ring system 1, with a slip ring body 2 and a brush unit 14. The slip ring body 2 is positioned fixedly on the shaft 4 with a hollow shaft portion or hollow shaft for conjoint rotation. Feed lines 35 in the form of stranded connectors are routed from the insulation ring 5 and the contact pins 8 arranged there through the hollow shaft or hollow shaft portion of the shaft 4 to the winding system 28 (not shown in greater detail in this figure) of the rotor 27. These feed lines 35 either lie freely in the hollow shaft or are embedded in a type of heat conducting paste, in order to obtain satisfactory thermal contact of the shaft 4.

[0056] Cooling of the slip ring body 2 from the inside and the shaft 4 can then take place as a result of the cavity 11 which is then configured between the outer circumferential surface of the hollow shaft and the inner surface of the slip ring body 2, via bores 21 in the end portions 12 which lie on the hollow shaft portion and are configured, in particular, as webs.

[0057] Here, the cooling takes place, in particular, by way of an air flow which is arranged by way of a fan unit 19 on the connector side 40. Here, a fan 20 sucks or presses a cooling air flow into the slip ring housing 17 which, by way of corresponding design of guide and conducting devices, guides the cooling air flow and steers it onto the heat sources of the slip ring system 1.

[0058] In the present case, the fan 20 is responsible, in particular, for the cooling air 33 through the cavity 11. Here, air from the surrounding area (from the nacelle in the case of a wind generator) is sucked in and is output again via an air outlet 36 at the slip ring system 1.

[0059] FIG. 6 shows the course of the cooling air flows 33 arrangement according to FIG. 5. It can be seen here, in particular, that a heat input 34 into the cooling air 33 which is conducted through the cavity 11 takes place from the slip rings 3 and also from the shaft 4 and therefore also from the feed lines 35 (stranded conductors or rail system).

[0060] FIG. 7 shows a perspective illustration of the slip ring system 1 from the bearing side 39. Here, the slip ring housing 17 is shown with its air inlets 18 and air outlets 38 which make cooling of the slip ring system 1 possible. The brush unit 14 is supported in the slip ring housing 17. The slip ring body 2 with its slip rings 3 is positioned radially further to the inside and on a shaft 4 or hollow shaft or hollow shaft portion. The grounding ring 6 has openings 13, via which cooling air 33 can then be conducted via the bores 21 of the end portions 12 into and out of the cavity 11. The slip ring housing 17 is adjoined axially by a fan unit 19 which adjusts the fan 20 and also its distribution of the cooling air flows.

[0061] With the aid of the fan 20, the heated air is then preferably is sucked in from the cavity 11 and is discharged to the outside from the slip ring housing 17 through the fan cap 36. The contact pins 8 are also called in the process.

[0062] As a result, the temperatures of the slip ring system 1 and of the entire electrical machine 24 can be reduced considerably. This leads to smaller overall designs of the slip ring system 1 becoming possible, or higher power levels being achieved with an identical overall design.

[0063] In addition to this cooling of the cavity 11, additional cooling of the slip ring system 1 is possible via the grooves 9 of the running surfaces 10 and the axial openings in the slip rings 3 and the insulating segments 7 of fan-like configuration. The shapes of the insulating segments 7 and possibly a plurality of insulating segments 7 ideally form a fan here which is provided to distribute a cooling air flow in the direction of the parts to be cooled of the electric machine 24.

[0064] Dynamoelectric machines 24 of this type with a slip ring system 1 are configured, in particular, as double-fed asynchronous machines (ASM) which are preferably used as generators in the wind power plants in the power range between 0.5 and 8 MW. Here, the wind power plants can be erected on-shore or offshore.