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Title:
ROTATING ELECTRIC MACHINE WITH BRACING MEANS
Document Type and Number:
WIPO Patent Application WO/2003/049252
Kind Code:
A1
Abstract:
A rotating electric machine comprises a rotor, a stator and stator windings, the stator windings including high voltage cable forming coil end arcs at the axial ends of the stator, the coil end arcs (18, 19) at at least one end of the stator being fixed by bracing means forming axial and radial spaces between the coil end arcs (18, 19). Said bracing means include blocks (1) each surrounding the circumference of the cable at one point of one of the coil end arcs (18, 19) and being interconnected with at least one other block (1) on another coil end arc (18, 19), thus forming a chain of blocks (1) fixing these coil end arcs (18, 19) at another. Said blocks (1) are interconnected by covers (10, 11) that are provided on the chain end blocks and are hold together by string means.

Inventors:
ALFREDSON STEFAN (SE)
WACHOWSKI ANDRZEJ (SE)
Application Number:
PCT/CH2002/000644
Publication Date:
June 12, 2003
Filing Date:
November 29, 2002
Export Citation:
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Assignee:
ALSTOM SWITZERLAND LTD (CH)
ALFREDSON STEFAN (SE)
WACHOWSKI ANDRZEJ (SE)
International Classes:
H02K3/50; (IPC1-7): H02K3/50; H02K3/40
Domestic Patent References:
WO1998020597A11998-05-14
WO1998034327A11998-08-06
Foreign References:
DE8909824U11990-12-20
Attorney, Agent or Firm:
ALSTOM (SWITZERLAND) LTD (CHSP Intellectual Property Brown Boveri Strasse 7/699/5 Baden, CH)
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Claims:
CLAIMS
1. A rotating electric machine having a rotor, a stator and stator windings, the stator windings including high voltage cable forming coil end arcs (1619) at the axial ends of the stator, the coil end arcs (1619) at at least one end of the stator being fixed by bracing means forming axial and radial spaces between the coil end arcs (1619), c h a r a c t e r i z e d in that said bracing means include blocks (1) each surrounding the circumference of the. cable at one point of one of the coil end arcs (1619) and being interconnected with at least one other block (1) on another coil end arc (16 19), thus forming a chain of blocks (1) fixing these coil end arcs (1619) at another, said blocks (1) being interconnected by covers (10,11) that are provided on the chain end blocks (1) and are hold together by string means (13).
2. A rotating electric machine according to claim 1, wherein each block (1) is divided in two mating parts (2, 3) being interconnected by snapin means (at 5,6).
3. A rotating electric machine according to claim 2, wherein said snapin means involve cocks and receptacles.
4. A rotating electric machine according to any of claim 13, wherein each block (1) is circular cylindrical with an opening (4) for the cable radially extending through its centre.
5. A rotating electric machine according to claim 4, wherein each cover (10,11) has a circular recess (14, 15) fitting the end of one of said chain end blocks (1).
6. A rotating electric machine according to any of claim 45, wherein each block (1) has an axial hole (7, 8) extending along its cylinder axis, the hole (7,8) forming a seat for a pin (9) that is radially fixing two adjacent blocks (1) and allows these blocks (1) to be turned round their cylinder axis.
Description:
ROTATING ELECTRIC MACHINE WITH BRACING MEANS The present invention concerns a rotating electric machine having a rotor, a stator and stator windings, the stator windings including high voltage cable forming coil end arcs at the axial ends of the stator, the coil end arcs at at least one end of the stator being fixed by bracing means forming axial and radial spaces between the coil end arcs.

A rotating electric machine according to the pream- ble is known from WO 9834327, which hereby is incorpora- ted by reference. Machines of that kind use high voltage cables for their stator windings. As several layers of cable are placed upon each other at the ends of the sta- tor, the problem arises, that mounting of the rotor of the machine is hampered by coil end arcs protruding towards the centre of the stator.

To deal with that problem WO 9834327 teaches use of bracing means consisting of several plates being mounted on bolts. The bolts are fixed outside the coil end arcs and extend into these. At certain intervals one of said plates is mounted on the bolts with the aid of nuts, each plate pressing a number of coil end arcs outwardly against a preceding plate. Thus, all of the coil end arcs can be removed from the space needed for mounting the rotor.

A problem with the bracing means of the machine accor-ding to WO 9834327 is that it is usable only for parallel parts of adjacent coil end arcs. This means that use of the known bracing means is limited to the very top of said arcs. Furthermore, the plates of the known bra- cing means are provided to brace several coil end arcs in different layers at a time. This makes it quite difficult to brace said arcs with an even force and not to clamp one of them so hard its outer layer of semiconducting material is not damaged.

The object of the present invention is to obviate the problems with the bracing device of the known machine according to WO 9834327.

This object is solved by a rotating electric machine according to the preamble, the machine being characteri- zed by said bracing means including blocks each surroun- ding the circumference of the cable at one point of one of the coil end arcs and being interconnected with at least one other block on another coil end arc, thus forming a chain of blocks fixing these coil end arcs at another, said blocks being interconnected by covers that are provided on the chain end blocks and are hold together by string means.

By interconnecting only one coil end arc in every coil end arc layer at a time it is easier than before to place the bracing means at a desired place. Furthermore, the covers and string means used to hold together each chain of blocks is easier to handle in a narrow space than a wrench to turn a nut holding one of the prior art plates.

Preferably each block is divided in two mating parts being interconnected by snap-in means. This solution simplifies the mounting of the blocks and provides for easy adjustment when necessary, the prefered solution being snap-in means involving cocks and receptacles.

According to. one embodiment each block is circular cylindrical with an opening for the cable radially ex- tending through its centre. It is obvious that this solution facilitates turning of one block against an- other, because there are no sharp edges risking to damage an adjacent coil end arc.

Turning of the blocks against one another is simpli- fied even more if each cover has a circular recess fit- ting the end of one of said chain end blocks and if each block has an axial hole extending along its cylinder axis, the hole forming a seat for a. pin that is radially

fixing two adjacent blocks and allows these blocks to be turned round their cylinder axis.

A preferred embodiment of the invention is described in the following with reference to the accompanying drawing.

In the schematic drawing: Fig. 1 is a top plan view of a block; Fig. 2 is an elevational view of two blocks and a pin for these; Fig. 3 is a top plan view of a top cover; Fig. 4 is an elevational view of two covers and strings for interconnecting them; Fig. 5 is a bottom plan view of a bottom cover; Fig. 6 is an elevational view of a block assembly in a first turning position; Fig. 7 is a top view of the block assembly in said first turning position; Fig. 8 is an elevational view of a block assembly in a second turning position; and Fig. 9 is top view of the block assembly in said second turning position.

In Figs. 1-2 substantially circular cylindrical blocks 1 are shown in a disassembled mode. As can be seen each block 1 consists of two parts 2,3 that together define a central opening 4. The parts 2,4 have mating faces 5,6, on which snap-in means, such as cocks and receptacles, can be provided (not shown). In its top and bottom face 7,8 each block 1 has a central hole 7,8, extending in an axial cylinder direction of the blocks 1.

In these holes 7,8 a pin 9 is insertable, the pin 9 defining a turning axis for one block 1 against the other.

In Figs. 3-5 annular covers 10, 11 are shown in a disassembled mode. The top cover 10 has recesses 12, into which strings 13 fastened at the bottom cover 11 fit for interconnecting the two covers 10, 11. Furthermore, each

cover 10,11 has a circular recess 14,15, into which the blocks 1 fit rotatingly.

In Figs. 6-9 assemblies of blocks 1 and covers 10, 11 are shown together with high voltage cable strands belonging to different coil end arcs 16,17, 18,19. As can be seen the arcs 16,17 in Figs. 6 and 7 are in parallel with each other, whereas the arcs 18 and 19 in Figs. 8 and 9 form an angle one against the other. Still the same kind of blocks 1 and covers 10,11 are used, however with the blocks l being turned slightly according to said angle.

The invention is not limited to the embodiment described above and can be varied in different ways within the scope of the accompanying claims.