WO2014108276A2

WO2014108276A2 - Arrangement for sealing slots

Info

Publication number: WO2014108276A2
Application number: PCT/EP2013/076722
Authority: WO
Inventors: Armin Piur
Original assignee: Abb Schweiz Ag
Priority date: 2013-01-11
Filing date: 2013-12-16
Publication date: 2014-07-17
Also published as: WO2014108276A3

Abstract

The invention relates to a slot sealing arrangement (200) for sealing a slot (6) in an electrical machine, said slot (6) being filled with conductor bars (4) or coils, wherein the slot sealing arrangement (200) comprises a slot wedge (1) and a pressure piece (2) which extend in the direction of a longitudinal axis (30). The slot wedge (1) and the pressure piece (2) are configured, when viewed transversely to the longitudinal axis (30), as a wedge/opposing wedge combination that can be wedged against one another. The pressure piece is configured as a spring element (2) the spring force of which is activatable by the spring element (2) being wedged against the slot wedge (1) by means of the spring element (2) being moved relative to the slot wedge (1) in the direction of the longitudinal axis (30).

Description

Arrangement for Versch Hessen of grooves

TECHNICAL AREA

The invention relates to a device for closing a filled with conductor bars or coils groove of an electric machine, and a device having this electrical see machine. Here are understood by the electric machine both motors, as well as generators.

STATE OF THE ART

On the arranged in the grooves of electrical machines conductor bars and coils act under the interaction of the conductors flowing through the electric current and the magnetic field in the air gap forces changing direction. In addition, the winding should be held reliably in the groove even with vibration and subsidence of the winding. It is therefore necessary to keep these conductors essentially free of play in the grooves.

This holding or fixing usually takes place by wedging under mechanical pretensioning. In many known Nutverschlussanordnungen the conductor bars or coils are pressed by applying balancing strips and trapezoidal wedges against the groove bottom. To compensate for settling phenomena during operation, either resilient intermediate layers, e.g. a corrugated spring (see, for example, DE2165727A), provided between splines and conductor bars or coils, or the wedge itself acts as a feeder element, such as in the case of CH525581 A.

The problem of these proposed solutions is that the achievable travel is typically not sufficient to ensure a permanent sufficient fixation of the conductor bars or coils in the groove of an electrical machine

Another approach followed, for example, EP0639882A1, which suggests that the elasticity of the Nutenkeils (slot slot called English) used selectively transverse to its longitudinal direction to obtain larger spring travel in the radial direction - ie in the direction of a vertical axis of the slot closure arrangement.

The problem of this approach lies in the fact that with increasing elasticity of acting as a sliding block Nutenstein the travel in comparison to the abovementioned solution proposals is indeed vergrosserbar, but on the condition that significant losses in the spring force are accepted. In the following, a solution proposal should be presented in the present document, with which both a sufficient spring travel, as well as a sufficient compressive force can be exerted on the conductor bars or coils in the groove of the electric machine, so that at least some of the disadvantages of known Nutverschlussanordnungen can be avoided.

PRESENTATION OF THE INVENTION

The idea of the invention essentially consists in designing the pressure piece to form a fully-fledged spring element whose spring travel is significantly greater in comparison to known solutions.

With the basic version of the slot closure arrangement described below, these goals can be achieved. For this purpose, the slot closure arrangement for closing a slot filled with conductor bars or coils groove of an electric machine comprises a Nutenkeil and a pressure piece. Both the key wedge, as well as the pressure piece extend in the direction of a predetermined by their shape and / or the groove direction of the groove longitudinal axis. The grooved wedge and the thrust piece are formed transversely to the longitudinal axis as wedge counter-wedge combination wedged against each other. In this case, the pressure piece is designed as a spring element whose spring force can be activated by wedging the spring element against the Nutenkeil by means of a displacement of the spring element relative to the Nutenkeil in the direction of the longitudinal axis, in particular during the first insertion of the Nutverschlussanordnung in the groove of the electric machine. The spring element forms a bending beam arrangement in the direction of a transverse axis extending transversely to the longitudinal axis, so that the spring element can be deflected by the key in the direction of a vertical axis transverse to the longitudinal axis and transverse to the transverse axis, so that the spring element in the installed state of the slot closure arrangement in the direction the vertical axis can exert on the ladder bars or coils.

In order to be able to develop maximum spring action, the bending beam arrangement advantageously extends in a single arc over a majority of the slot closure arrangement.

With this constellation, for example, a significantly greater spring travel can be achieved compared to the solution according to EP0639882A1. A greater spring travel is advantageous not only for applying the pressure force for fixing the conductor bars or coils in the groove, but also to be able to compensate for assembly, shape and position tolerances. All this contributes advantageously to a better operational capability due to the improved fatigue strength of the spring action. In a further developed embodiment of the basic design of the slot closure arrangement, the spring element has a second surface facing away from the spline, which in the relaxed state of the spring element before installation in the electric machine in cross-section perpendicular to the longitudinal axis viewed at least in the region of the vertical axis extending in the direction of the longitudinal axis Has indentation. The indentation ensures that the second surface during installation of the spring element in the groove of the electric machine has no full-surface support in the direction of the conductor bars or coils. Seen in cross-section transverse to the longitudinal axis can not be pressed through the non-solid surface so a portion of the spring element in the region of the vertical axis of Nutenkeil targeted against the recess in the direction of the conductor bars or coil, so that depending on the dimensions of the indentation considerable spring travel can be realized.

In particular in connection with a spring element made of fiber-reinforced material, good fatigue strength and spring values can be achieved if the indentation of the second surface in the cross-section perpendicular to the longitudinal axis is concave.

If a self-centering effect of the wedge counter wedge arrangement is desired, this can be realized, for example, by the fact that the spring element has a first surface facing the grooved wedge, which first surface in a relaxed state of the spring element before installation in the electric machine in a Cross-section seen perpendicular to the longitudinal axis, at least in the region of the vertical axis is convex. At the same time, the key wedge has a third surface facing the spring element, which third surface is concave in cross section perpendicular to the longitudinal axis.

In order to achieve a fairly precise predefinable geographic location of the force application of the pressure applied to the spring element during wedging of the key, a first radius of curvature of the first surface may be less than a third radius of curvature of the third surface, so that the key will compress during wedging the spring element exerts mainly in a transverse center area at the vertical axis. At the same time, the degree of the force to be applied during driving in the direction of the longitudinal axis in relation to the pressure force of the spring element resulting in the vertical axis can be kept within reasonable limits due to the different dimensioning of the radii of curvature. Good results can be achieved if the third radius of curvature is at least 5% larger than the first radius of curvature.

When the conductor bars or coils in the groove are to be cooled, the groove wedge have at least one ventilation slot extending in the direction of the vertical axis. If necessary, the ventilation slot can be arranged in the region of a wedge shoulder of the key be. If necessary, several ventilation slots can be arranged in the area of both wedge shoulders of the key.

With respect to the spring element, it has been found that the spring element of a slot closure arrangement has good spring properties when it comprises a plurality of electrically insulating fibers unidirectionally oriented in the direction of the transverse axis and interconnected by a heat-resistant resin. This creates a spring element with which spring forces of desired strength acting along the transverse axis in the direction of the vertical axis can be activated. The transverse axis and the vertical axis extend in an imaginary plane, which represents a cross section of the groove and the slot closure arrangement. A maximum spring travel is thus approximately transversely about a line in the direction of the vertical axis.

The strip-shaped spring element seen in the plan view from the direction of the vertical axis is easily configurable depending on the requirements with regard to the desired spring travel, the spring forces and the installation situation. Due to the producibility of larger spring travel of the spring element settling phenomena in the winding structure are better compensated. As a result, the intervals of the maintenance intervals can be increased and the availability of the electrical machine as a whole can be improved. The more reliable fastening of the windings as a result of the fatigue-resistant spring element contributes significantly to the fatigue strength of the groove closure in the groove and thereby makes a significant contribution to operational safety and to the reduction of potential damage.

For the function of a slot closure arrangement according to the invention, the fibers should be electrically insulating. Representatives of a large number of materials suitable for this purpose are, for example, glass fibers and / or para-amide fibers such as Kevlar.

If a Nachverkeilen - for example, on the occasion of a maintenance - to be further facilitated, the fiber composite can have from the fibers in the direction of the vertical axis abrasion-free or at least abrasion-resistant outer layers.

BRIEF DESCRIPTION OF THE DRAWINGS

Hereinafter, several embodiments of the invention will be explained in detail with reference to the drawings. This shows purely schematically

FIG. 1 is a cross-sectional view of a first embodiment of a slot closure assembly in the groove of an electric machine; FIG. 2 shows a cross-sectional view of a second embodiment of a slot closure arrangement in the groove of an electrical machine,

FIG. 3 is a cross-sectional view of a spring element in the view of Figure 2, and

FIG. 4 is a side view, partly in section, of a keyway of the second embodiment;

FIG. 5 is a plan view of the keyway according to the second embodiment, and FIG

FIG. 6 shows a side view with a partial section of a spring element according to the second embodiment.

The reference numerals used in the drawings and their meaning are listed in the list of reference numerals. Basically, the same parts are provided with the same reference numerals in the figures. The described embodiments are exemplary of the subject invention and have no limiting effect.

WAY FOR CARRYING OUT THE INVENTION

1 shows a slot closure arrangement 200 according to a first embodiment, wherein the reference numeral 1 denotes an upper prismatic body - in the following Nutenkeil called - and the reference numeral 2 a lower prismatic body - in the following pressure piece or its function called spring element. Groove key 1 and thrust piece 2 press together one or more provided with an insulation 3 conductor bar or conductor bars 4 against the bottom of the punched in the stator lamination body 5 groove 6 of an electric machine by the wedge shoulders 29, 29 'of the Nutenkeils 1 against the complementary shaped recesses 7 in the stator lamination body 5 is supported. The groove 6 has a classic dovetail shape.

Due to its function as a spring element, the pressure piece is henceforth called simplistic spring element 2.

Due to the electrical requirements of the grooved wedge 1 and also arranged between the conductor bar 4 and spring element 2 slide pad 10 is made of a laminate with glass fiber mats, mineral fillers and epoxy resin as a binder. The grooved wedge 1 is more resistant to bending than the spring element 2 in the direction of the transverse axis 31. In this embodiment, the spring element 2 was not necessarily made of glass or Kevlar fibers which are oriented unilaterally in the direction of the transverse axis 31 and cast in heat-resistant resin, provided that required spring action can be achieved with other fiber-reinforced materials. The spring element 2 has seen in the relaxed state of the spring element 2 before installation in the electric machine in cross section perpendicular to the longitudinal axis 30 at least in the region of the vertical axis 32 in the direction of the longitudinal axis 30 extending indentation 22, so that the second surface 9 during installation the spring element in the groove of the electric machine has no full-surface support in the direction of the conductor bars 4.

The spring element has on its side facing the Nutenkeil 1 a first surface 17, 17 ', which laterally of the vertical axis 32 has two graduated in height sections. The offset in height produces a transversely arranged projection 12, which contacts the slot wedge 1 during installation of the slot closure arrangement in the electric machine, while the offset sections do not touch the slot wedge 1. The distance between the first surface 17 'and an inner contour of the Nutenkeils 1 forms a first spring section 14th

A height of the indentation 22 extending in the direction of the vertical axis 32 forms a further, second spring section 15.

By this constellation, the spring element 2 forms in the direction of transverse to the longitudinal axis 30 extending transverse axis 31 a bending beam arrangement. About the projection 12 is in wedging the spring element 2 against the Nutenkeil 1 acting in the direction of the vertical axis 32 against the conductor 4 compressive force applied to the spring element 2, wherein the pressure over those portions of the second surface which touch the sliding pad 10 in the latter is initiated.

FIG. 2 shows a slot closure arrangement 20 according to a second embodiment. Since the second embodiment is very similar to the first embodiment, reference will be made below only to the essential differences and their effect. Identical or equivalent elements have therefore been given the same reference signs.

In contrast to the second embodiment, the indentation 22 of the second surface 9 seen in cross section perpendicular to the longitudinal axis 30 has a concave shape. The grooved wedge 1 has a spring surface 2 facing the third surface 8, which third surface 8 has seen in cross-section perpendicular to the longitudinal axis 30 has a concave shape. The advantage of this embodiment lies in the fact that a self-centering effect can be achieved when the slot closure arrangement wedges.

Next, the spring element 2 a the Nutenkeil 1 facing first surface 17, which first surface 17 in a relaxed state of the spring element prior to installation is seen in the electric machine in a cross section perpendicular to the longitudinal axis, at least in the region of the vertical axis 32 is convex.

The arcuate or kreisringab- cut-like shape of the spring element 2 seen in cross-section perpendicular to the longitudinal axis 30 is particularly well suited to make the spring element as a fiber-reinforced component.

This embodiment will now be briefly discussed in conjunction with FIG. 2, FIG. 3 with FIG. 4 and FIG. As can be seen, in particular, from the region 21 shown broken up, the electrically insulating spring element 20 has a multiplicity of electrically insulating fibers 19 which are aligned unidirectionally in the direction of the transverse axis 31 and which are permanently connected to one another by a heat-resistant resin. This results in a spring element with which along the transverse axis 31 in the direction of the vertical axis 32 acting spring forces predefinable strength dimension and activate.

The electrically insulating fibers are formed in this embodiment of the spring element of a plurality of glass fibers 19, wherein the glass fiber content of the spring element preferably about two-thirds and the resin content preferably about 1/3 percent by weight.

The transverse axis 31 and the vertical axis 32 extend in an imaginary plane, which represents a cross section of the groove 6 and the slot closure arrangement 20. A maximum spring travel is therefore ideally located approximately transversely in the direction of the vertical axis 32. The term "transversely" refers to a position in the direction of the transverse axis 31 relative to the entire width 18 of the slot closure arrangement.

It should also be noted that the cross section shown in FIG. 2 has a hatching which does not correspond to an advantageous fiber course of the fibers in the spring element, since the fibers would be interrupted in the direction of the transverse axis 31 at least in the region of the indentation 22. For this reason, the actual fiber path runs along the arc section, so that no or at least as few fibers as possible are interrupted by the indentation 22 extending transversely to the fiber direction.

Coming back to the convex shape of the second surface 9 of the spring element 2 and the concave shape of the spline 1, it makes sense to keep the radii of curvature of the surfaces different, so that the friction between the spring element 2 and spline 1 can be kept below a reasonable threshold in such a way that the wedging force in relation to the adhesion between the spring element 2 and the key 1 moves in a favorable frame. This can be achieved, for example, by virtue of the fact that a first radius of curvature 26 of the first surface 30 is smaller than a third radius of curvature 27 of the third surface 8, so that the wedging wedge 1 wedges its pressure onto the spring element 2 mainly in a transverse center region 26 at the vertical axis 32 exercises. In the present example of the illustrated second embodiment, the third radius of curvature 27 is at least five percent greater in magnitude than the first radius of curvature 26.

As is further apparent from FIG. 5, the grooved wedge 1 has a plurality of ventilation slots 16 extending in the direction of the vertical axis 32 at its two wedge shoulders 29, 29 '. These ventilation slots 16 are used for heat dissipation of the thermal energy from the conductor rods 4. The respect to the longitudinal axis 30 axially extending slots 1 1 in the end faces of the Nutenkeils 1 allow, with a suitable tool or device to move the spring element 2 relative to the Nutenkeil 1.

From the side view with partial section of a spring element according to the second embodiment shown in FIG. 6, it can be seen that the indentation 22 has a shape extending in the direction of the longitudinal axis 30. Depending on the dimensions of the desired spring travel and extending in the direction of the vertical axis 32 thickness of the spring element 2, the prism-shaped, for example, parallel to the longitudinal axis or parallel to the first surface 17 may be arranged.

LIST OF REFERENCE NUMBERS

1 slot wedge / slot nut

2 spring element / pressure piece

3 isolation

4 conductor bar

5 stator laminations

6 groove of the electric machine

7 recess

8 third area

9 second area

10 sliding pad

1 1 axial slot

12 lead

14 first spring stretch

15 second spring stretch

16 ventilation slot

17, 17 'first surface

18 width

19 fibers

20, 200 slot closure arrangement

22 indentation

26 first radius of curvature

27 third radius of curvature

29, 29 'Wedge shoulder

30 longitudinal axis

31 transverse axis

32 vertical axis

Claims

PATENT CLAIMS E

1 . A slot closure arrangement (20, 200) for closing a slot (6) of an electric machine filled with conductor bars (4) or coils, wherein the slot closure arrangement (20) comprises a slot wedge (1) and a pressure piece (2) extending in the direction of a longitudinal axis Extend (30)

and wherein the grooved wedge (1) and the pressure piece (2), viewed transversely to the longitudinal axis (30), are designed as wedge-counterwedge combinations which can be wedged against each other,

characterized in that

the pressure piece is designed as a spring element (2) whose spring force can be activated by displacing the spring element (2) against the slot wedge (1) by means of a displacement of the spring element (2) relative to the slot wedge (1) in the direction of the longitudinal axis (30) is, wherein the spring element (2) in the direction of a transversely to the longitudinal axis (30) extending transverse axis (31) forms a bending beam arrangement, so that the spring element (2) from the wedge in the direction of a transverse to the longitudinal axis (30) and transversely to Transverse axis (31) arranged vertical axis (32) is deflectable so that the spring element can exert its spring force in the installed state of the slot closure arrangement in the direction of the vertical axis (32) on the conductor bars (4) or coils,

wherein the spring element (2) has a second surface (9) facing away from the slot wedge (1), which in the relaxed state of the spring element before installation in the electric machine in cross section perpendicular to the longitudinal axis (30) at least in the region of the vertical axis ( 32) has a recess (22) extending in the direction of the longitudinal axis (30), so that the second surface (9) during installation of the spring element in the groove of the electric machine has no full-surface support in the direction of the conductor bars (4) or coils.

2. slot closure arrangement (20) according to claim 1, characterized in that the indentation (22) of the second surface (9) is seen in cross section perpendicular to the longitudinal axis (30) concave.

3. Nutverschlussanordnung (20) according to any one of the preceding claims, characterized in that the spring element (2) has a the Nutenkeil (1) facing the first surface (17), which first surface (17) in a relaxed state of the spring element prior to installation in the electrical machine seen in a cross section perpendicular to the longitudinal axis, at least in the region of the vertical axis (32) is convex.

4. Nutverschlussanordnung (20, 200) according to any one of the preceding claims, characterized in that the spring element (2) comprises a plurality of electrically insulating fibers (19), which are aligned unidirectionally in the direction of the transverse axis (31) and interconnected by a resin are.

5. Nutverschlussanordnung (20, 200) according to claim 4, characterized in that the resin is a heat-resistant resin.

6. slot closure arrangement (20) according to any one of the preceding claims, characterized in that the Nutenkeil (1) a the spring element (2) facing the third

Surface (8), which third surface (8) is seen in cross-section perpendicular to the longitudinal axis (30) concave.

7. slot closure arrangement (20) according to claim 6, characterized in that a first radius of curvature (26) of the first surface (30) smaller than a third radius of curvature

(27) of the third surface (8), so that the wedge (1) when wedging its pressure on the spring element (2) mainly in a transverse center region (26) at the vertical axis (32) exerts.

8. Nutverschlussanordnung (20) according to claim 7, characterized in that the third radius of curvature (27) is at least 5% larger than the first radius of curvature (26).

9. slot closure arrangement (20, 200) according to any one of the preceding claims, characterized in that the Nutenkeil (1) has at least one in the direction of the vertical axis (32) extending ventilation slot (16).

10. slot closure arrangement (20, 200) according to claim 5, characterized in that at least one ventilation slot (16) in the region of a wedge shoulder (29) of the Nutenkeils (1) is arranged, optionally in the region of both wedge shoulders (29, 29 ') of the Nutenkeils (1 ).

1 1. Slot closure arrangement (20, 200) according to one of the preceding claims, characterized in that the bending beam arrangement extends in a single arc over a majority of the entire width (18) of the slot closure arrangement.

12. Electrical machine with at least one with conductor bars (4) or coils filled groove (6), characterized in that that groove (6) with a slot closure arrangement (20, 200) is closed according to one of the preceding claims.