AU2013322982A1

AU2013322982A1 - Segmented rotor for electrical machines

Info

Publication number: AU2013322982A1
Application number: AU2013322982A
Authority: AU
Inventors: Frank Bechmann; Manfred Kruger-Gotzmann; Peter Petereit; Kerstin Schenk; Christian Schiller; Dirk Winter
Original assignee: Siemens AG
Current assignee: Innomotics GmbH
Priority date: 2012-09-26
Filing date: 2013-09-11
Publication date: 2015-04-02
Anticipated expiration: 2033-09-11
Also published as: AU2013322982B2; DE112013004721A5; CL2015000754A1; DE102013209555A1; PE20150589A1; WO2014048739A1

Abstract

The invention relates to a rotor (1) for an electrical machine. The invention further relates to an electrical machine with such a rotor (1), and to a mill with such an electrical machine. In order to improve the availability of the rotor (1), according to the invention the rotor (1) has at least one support element (2) on a rotor surface (3) and at least two individual pole segments (4), each of which comprises at least one pole coil (5) and at least one pole core (6), wherein each of the individual pole segments (4) can be individually fixed to the at least one support element (2) by means of at least one mechanically detachable connection.

Description

PCT/EP2013/068783 / 2012P06535WO 1 Description Segmented rotor for electrical machines The invention relates to a rotor for an electrical machine. The invention further relates to an electrical machine having such a rotor, and to a mill having such an electrical machine. Such a rotor is employed for example in slowly running synchronous motors having a high torque, in particular for ore mills or compressors. The market requires a high level of availability in respect of said machines. In these approaches the rotor consists of the actual shaft to be driven and the electrically active rotor parts, such as pole coil and pole core. The electrically active rotor parts are combined on pole segments which are flange-mounted onto the shaft. The electrical excitation of the individual pole coils is effected by way of slip rings. The mounting of the rotor assemblies is complex and places the highest demands in terms of accuracy of shape on the rotor poles to be mounted, in particular in respect of radial and axial running. Group pole segments having for example four poles per segment are often currently used. The pole coils are connected to said pole segments in such a manner that it is not possible to replace the pole coils in the motor. The slip and sealing rings are also mounted on the pole segments. In order to replace a pole segment or a pole coil the entire group pole segment must be replaced. The mounting and demounting of said group pole segments in turn requires extensive demounting measures, such as for example the removal of sealing and slip rings, on the entire motor and is thus time-consuming. The object of the invention is to increase the availability of a rotor.

PCT/EP2013/068783 / 2012P06535WO 2 This object is achieved in that the rotor has at least one support element on a rotor surface and at least two individual pole segments, each of which comprises at least one pole coil and at least one pole core, wherein each of the individual pole segments can be individually fixed to the at least one support element by means of at least one mechanically detachable connection in each case. This object is furthermore achieved by an electrical machine having such a rotor and a stator, wherein the rotor is arranged concentrically with respect to the stator and the rotor surface faces the stator. Finally, this object is achieved by a mill having such an electrical machine. The approach to achieving the object of the present invention lies in the subdivision of at least two pole segments into supporting parts in the form of the at least one support element on the one hand and the at least two individual pole segments on the other hand, each of which comprises at least one pole coil and at least one pole core. The at least one support element holds the pole coils and pole cores which are fastened on the surface of the at least one support element. In this situation the fastening can be implemented in form-locked, material-locked or friction-locked fashion. As a result of attaching the individual poles on the rotor surface, in the event of damage the individual pole segment in question with the respective pole coil can be demounted without requiring that the associated support element be demounted. The high availability demanded by the market can therefore be ensured on account of the resulting particularly fast replacement of damaged pole coils. In addition, the component costs are greatly reduced by this measure. The advantage of the present invention thus consists in the fact that the individual poles can be individually demounted, PCT/EP2013/068783 / 2012P06535WO 3 which greatly simplifies and reduces maintenance and repair work. This is particularly important in the case of a rotor installed in a corresponding electrical machine because particularly restricted space conditions are frequently to be encountered there and at the same time prolonged machine downtimes can result in considerable economic losses. The accuracy of shape of the rotor is not negatively influenced as a result of subdividing the pole segment into supporting parts and individual pole segments, which means that increased requirements in respect of radial running and start-up can also be easily met. It is conceivable in this situation that the at least one pole coil and the at least one pole core of one of the individual pole segments can in each case be individually fixed by means of at least one mechanically detachable connection to the at least one support element. As a result of the separate fixing of the pole coil and of the pole core a particularly pinpoint repair is enabled in which exclusively the damaged component is replaced. In an advantageous embodiment of the invention the pole coils of at least two individual pole segments can be connected electrically in series by means of at least a first bus bar. In this situation the first bus bar can be fixed by means of a further mechanically detachable connection to at least the two individual pole segments, which ensures that the individual pole segment in question can be easily demounted in the event of damage. In a further advantageous embodiment of the invention the rotor has at least one sliding contact which can be connected electrically in each case to at least one of the pole coils of the individual pole segments. The at least one sliding contact can likewise be arranged on the rotor surface, which means that in the case of an electrical machine having such a rotor PCT/EP2013/068783 / 2012P06535WO 4 and one brush or a plurality of brushes at least one sliding contact is formed for transferring electrical power. The active parts of the rotor can thus be supplied with electrical power by means of the at least one sliding contact. In this situation it may be necessary to provide a plurality of sliding contacts, for example two sliding contacts for two electrical contacts in the case of a single-phase excitation and for example three sliding contacts for the three phases of an excitation by means of three-phase current. If the rotor and the electrical machine are embodied as a linear machine, then the at least one sliding contact in question in each case is an additional bus bar which can be supplied with electrical power by way of at least one brush. If the rotor is embodied as an actual rotor in the case of a rotary electric motor or generator, for example, the respective sliding contact is embodied as a slip ring which in turn can be supplied with electrical power by way of at least one brush. In a further advantageous embodiment of the invention the rotor has at least a second bus bar by means of which an electrical connection can be established in each case between the at least one sliding contact and at least one of the pole coils of the individual pole segments, wherein the at least one second bus bar can be fixed in mechanically detachable fashion on the respective individual pole segment. Through the use of the at least one second bus bar, which can be fixed in mechanically detachable fashion on the respective individual pole segment, an electrical connection is established between the at least one sliding contact and the respective active parts of the rotor. It is advantageous in this situation that thanks to the ease with which the at least one second bus bar can be demounted a damaged individual pole segment can be very easily replaced.

PCT/EP2013/068783 / 2012P06535WO 5 If two or more sliding contacts are provided, at least one second bus bar is required per sliding contact in order to guarantee the electrical connection to the respective individual pole segments. Furthermore, the at least one second bus bar can also be fixed in mechanically detachable fashion directly on the respective pole coil or - in case a first bus bar mentioned above is provided - on the at least one first bus bar. In a further advantageous embodiment of the invention the at least one support element is embodied at least as a section of a flange. In this situation the at least one support element can be embodied as a flange which is embodied in completely circumferential fashion in the circumferential direction or merely as a section of such a flange, wherein the section covers only a part of the full circumference. In particular, a plurality of such flange sections can then be provided. It is furthermore conceivable that the flange is embodied in one piece with the rotor or a shaft of the rotor or that the flange is a separate component which for example is fastened on the rotor shaft. In this situation the flange section or the flange preferably has a radial outer surface which extends in the axial direction at least over half the axial length of a pole core. A particularly reliable connection of the individual pole segment with the flange is thereby enabled. In a further advantageous embodiment of the invention the rotor has at least two support elements, wherein the rotor has sealing elements between two of the support elements for sealing purposes. The sealing elements enable reliable sealing of the rotor radially to the outside, such that the rotor and an electrical machine having such a rotor can be operated even under adverse conditions, such as for example in the presence of spray or splash water and/or foreign bodies or dust. Said sealing is particularly advantageous in the case of an PCT/EP2013/068783 / 2012P06535WO 6 application in a mill, in particular an ore mill, because dust and rock fragments and also spray water can constantly impair the operation of such an electrical machine there. When the support elements are mounted, a rotor sealed to the outside is produced here. The sealing elements can in particular be embodied as rubber seals. For example, two adjacent support elements each have a side face which touches the respective adjacent support element, where a groove is incorporated in the respective side face of the two support elements and where at least one sealing element is in turn incorporated into said groove or in the resulting recess between the two support elements. In particular, the sealing elements can be embodied in each case as a sealing ring comprising a support element in such a manner. It is also conceivable that the sealing elements together comprise a plurality of support elements. In a further advantageous embodiment of the invention the respective individual pole segment has a segment holder which is arranged between the respective pole core and the at least one support element. In this situation the respective segment holder can be optimized for rapid replacement of an individual pole segment, for example by connecting the respective segment holder to the respective support element in mechanically detachable fashion by way of a particularly easily accessible connection. When an individual pole segment is replaced, the individual pole segment together with the associated segment holder is then firstly released from the support element and only subsequently is the pole core or the pole coil released from the segment holder. In particular when the at least one support element is embodied at least in sections as a flange the segment holder can also be embodied as a type of carriage, where the at least PCT/EP2013/068783 / 2012P06535WO 7 one support element has a corresponding guide in which the carriage can be moved for example in the axial direction. It is conceivable in this situation that the fixing of the segment holder on the support element in the radial direction and an additional direction, such as for example the circumferential direction, is effected by the guide. The remaining degree of freedom of the carriage, for example in the axial direction, can be effected in particular by a stop together with a snap-action connection or locking device or a further mechanically detachable connection. The electrical machine described above can, as already mentioned above, be employed in a mill, for example an ore mill. Further applications, for example as a drive motor for a compressor, as a generator or as a linear electrical machine, can likewise be implemented. In particular, the electrical machine can be used as a generator for a wind turbine, which can be driven for example directly or by way of a gearing mechanism. In a further advantageous embodiment of the mill according to the invention the at least one support element of the rotor is embodied at least as a section of a flange, wherein the mill has a drum body, wherein the section of the flange is arranged on an axial end of the drum body. It is furthermore conceivable that the support element is also embodied as a flange running fully circumferentially in extent. The invention will be described and explained in detail in the following with reference to the exemplary embodiments illustrated in the figures. In the drawings: FIG 1 shows a section of an electrical machine according to a first exemplary embodiment of the rotor according to the invention, FIG 2 shows a further illustration of the first exemplary embodiment, PCT/EP2013/068783 / 2012P06535WO 8 FIG 3 shows a section of an electrical machine according to a second exemplary embodiment of the rotor according to the invention, FIG 4 shows a further illustration of the second exemplary embodiment, and FIG 5 shows a section of an electrical machine according to a third exemplary embodiment of the rotor according to the invention. Figure 1 shows a section of an electrical machine illustrating a first exemplary embodiment of the rotor 1 according to the invention. The electrical machine has a cylindrical rotor 1 which is surrounded by a stator 11 arranged concentrically with respect to the rotor 1. The rotor 1 has a rotor surface 3 and also a support element 2 on the rotor surface 3. In the context of the first exemplary embodiment the support element 2 is embodied as a flange running around in the circumferential direction. It is also conceivable that the support element 2 merely constitutes a section of a flange in the circumferential direction and in particular a plurality of such flange sections are provided. Individual pole segments 4 are fastened on the support element 2 by means of a mechanically detachable connection in each case. The individual pole segments 4 each have a pole core 6 and also a pole coil 5 passing around the pole core 6. In addition the individual pole segments 4 each have a segment holder 10 which in the case of an individual pole segment 4 connected to the support element 2 is situated between the support element 2 and the pole core 6 or the pole coil 5. In this situation the segment holder 10 is embodied as a type of carriage which can be inserted axially in a corresponding guide of the support element 2. The segment holder 10 embodied as a carriage is fixed in the radial direction and in the circumferential direction by the guide. In addition, a stop not illustrated in detail can be provided which together with PCT/EP2013/068783 / 2012P06535WO 9 a snap-action connection, a locking device or a further mechanically detachable connection effects a complete fixing of the segment holder 10 and thus of the entire respective individual pole segment 4. Figure 2 shows a further illustration of the same electrical machine, where the same reference characters identify the same objects. In the event that an individual pole segment 4 is damaged or needs to be replaced for other reasons the corresponding individual pole segment 4 can be easily released from the support element 2 thanks to the mechanically detachable connection of the two parts. As a result of the fact that for example in the case of a repair only single individual pole segments 4 need to be removed and installed again, the repair effort and the time required for the repair are significantly reduced, which means that the availability of the rotor 1 and thus of the electrical machine is increased. Figure 3 shows a section of an electrical machine according to a second exemplary embodiment of the rotor 1 according to the invention. The rotor 1 has a rotor surface 3 and also a plurality of support elements 2 on the rotor surface 3. Individual pole segments 4 are in each case fastened individually on each of the support elements 2 by means of a mechanically detachable connection. The individual pole segments 4 each have a pole core 6 and also a pole coil 5 passing around the pole core 6. The support elements 2 are arranged directly adjacent to one another in the circumferential direction, where in each case a groove 12 is incorporated on those faces of each support element 2 which face towards adjacent support elements 2. Sealing elements, for example in the form of rubber seals, can be incorporated into said groove 12, which seal the rotor 1 radially to the outside. Dirt and water are thereby reliably excluded from the interior of the rotor 1.

PCT/EP2013/068783 / 2012P06535WO 10 Figure 4 shows a further illustration of the electrical machine according to the second exemplary embodiment, where the same reference characters identify the same objects. If an individual pole segment 4 is damaged or needs to be replaced for other reasons the corresponding individual pole segment 4 can be easily released from its associated support element 2 thanks to the mechanically detachable connection of the two parts. Figure 5 shows a section of an electrical machine according to a third exemplary embodiment of the rotor 1 according to the invention. The rotor 1 has support elements 2 on the rotor surface 3, where only one of the support elements 2 is illustrated in Figure 3 for the sake of improved clarity. Individual pole segments 4 are in each case connected to the associated support element 2 by means of a mechanically detachable connection, where the individual pole segments 4 each have a pole core 6 and also a pole coil 5 which passes around the pole core 6. On its rotor surface 3 the rotor 1 furthermore has a sliding contact 8 which here is embodied as a slip ring. The pole coils 5 of the same support element 2 or also of two adjacent support elements 2 can be connected in series by means of first bus bars 7. An electrical connection is established between the sliding contact 8 and the pole coils 5 by means of a second bus bar 9, where applicable using the first bus bars 7. Both the first bus bars 7 and also the second bus bars 9 are in this situation fastened in mechanically detachable fashion on the pole coil 5 of the respective individual pole segment 4. This ensures that in the case of a repair single individual pole segments 4 can be removed and installed again, which means that the repair effort and the time required for the repair are significantly reduced, which results in an increase in the availability of the rotor 1 and thus of the electrical machine.

PCT/EP2013/068783 / 2012P06535WO 11 To summarize, the invention relates to a rotor for an electrical machine. The invention further relates to an electrical machine having such a rotor, and to a mill having such an electrical machine. In order to increase the availability of the rotor it is proposed that the rotor has at least one support element on a rotor surface and at least two individual pole segments, each of which comprises at least one pole coil and at least one pole core, where each of the individual pole segments can be individually fixed to the at least one support element by means of at least one mechanically detachable connection in each case.

Claims

1. A rotor (1) for an electrical machine, which has - at least one support element (2) on a rotor surface (3) and - at least two individual pole segments (4), each of which comprises at least one pole coil (5) and at least one pole core (6), wherein each of the individual pole segments (4) can be individually fixed to the at least one support element (2) by means of at least one mechanically detachable connection in each case.

2. The rotor (1) as claimed in claim 1, wherein the pole coils (5) of at least two individual pole segments (4) can be connected electrically in series by means of at least a first bus bar (7).

3. The rotor (1) as claimed in one of the preceding claims, wherein the rotor (1) has at least one sliding contact (8) which can be connected electrically in each case to at least one of the pole coils (5) of the individual pole segments (4).

4. The rotor (1) as claimed in claim 3, wherein the rotor (1) has at least a second bus bar (9) by means of which an electrical connection can be established in each case between the at least one sliding contact (8) and at least one of the pole coils (5) of the individual pole segments (4), wherein the at least one second bus bar (9) can be fixed in mechanically detachable fashion on the respective individual pole segment (4).

5. The rotor (1) as claimed in one of the preceding claims, wherein the at least one support element (2) is embodied at least as a section of a flange.

6. The rotor (1) as claimed in one of claims 1 to 4, PCT/EP2013/068783 / 2012P06535WO 13 wherein the rotor (1) has at least two support elements (2), wherein the rotor (1) has sealing elements between two of the support elements (2) for sealing purposes.

7. The rotor (1) as claimed in one of the preceding claims, wherein the respective individual pole segment (4) has a segment holder (10) which is arranged between the respective pole core (6) and the at least one support element (2).

8. An electrical machine having a rotor (1) as claimed in one of the preceding claims and a stator (11), wherein the rotor (1) is arranged concentrically with respect to the stator (11) and the rotor surface (3) faces towards the stator (11).

9. A mill having an electrical machine as claimed in claim 8.

10. The mill as claimed in claim 9 having a rotor (1) as claimed in claim 5, wherein the mill has a drum body, wherein the section of the flange is arranged on an axial end of the drum body.