Electrical machinery

Abstract

The present invention relates to an electric machine, in particular a generator, comprising a stator including a winding overhang (1), a rotor (13) rotatably arranged about a rotor axis (3) in the stator, and a heat exchanger (6), said heat exchanger (6) fluidly connected to the winding overhang (1) via a coolant shaft (17) arranged radially outside the winding overhang (1) and extending at least partially substantially along a circumferential direction (9) and bounded in a radial direction (8) by an outer surface, such that the winding overhang (1) can be cooled by a continuous flow of fluid over the heat exchanger (6) and the winding overhang (1). In order to obtain a particularly uniform cooling of the winding overhang (1), it is provided according to the invention that a plurality of guide elements (11) arranged distributed along the circumferential direction (9) are provided in the coolant shaft (17) for at least partially redirecting the fluid flow directed in the circumferential direction (9) in the coolant shaft (17) into a radial flow towards the winding overhang (1) and for distributing the flow over a plurality of regions of the winding overhang (1).

Description

Technical Field

[0001] The present invention relates to an electric machine, in particular to a generator, comprising a stator including a winding overhang, a rotor rotatably arranged around a rotor shaft in the stator, and a heat exchanger, wherein the heat exchanger is fluidly connected to the winding overhang via a coolant shaft, the coolant shaft being arranged radially outside the winding overhang, at least partially extending substantially along the circumferential direction and being radially delimited by an outer surface, so that the winding overhang can be cooled by a continuous flow of fluid covering the heat exchanger and the winding overhang.

[0002] The first-named type of electric machine is well known from the prior art. The temperature of the winding overhang continues to pose difficulties in constructing this type of machine. As a result, the winding overhang typically heats up significantly during operation due to the losses occurring in this region, which is why this type of machine is usually designed as an externally ventilated machine, with one or more fans arranged in the flow path of the cooling fluid, the flow path being connected so as to lead from the heat exchanger to the winding overhang and then back to the heat exchanger via different return flow paths, for example through a laminated stator core. Thus, a circulating flow is realized in the machine, and the cooling fluid, typically air, absorbs heat in the winding overhang and releases it in the heat exchanger.

[0003] In this type of machine, the heat exchanger is generally arranged outside the rotation axis, in principle in the upper, lower or side regions of the stator, so that the individual winding overhang regions along the flow path of the cooling fluid are spaced further away from the heat exchanger and the fan than from others, thereby making it difficult to achieve uniform cooling over the entire circumference of the winding overhang, and hot spots that can particularly cause damage to the insulator generally appear.

[0004] This is addressed by the present invention. The object of the present invention is to identify a first-named type of machine that enables particularly uniform cooling of winding overhangs.

[0005] According to the present invention, this objective is achieved by an electromechanism of the first named type provided in the coolant shaft, which includes a plurality of guide elements dispersed along the circumferential direction to at least partially redirect the circumferentially oriented fluid flow in the coolant shaft into a radial flow toward the winding overhang, and to distribute the flow to a plurality of regions of the winding overhang.

[0006] In the course of the present invention, it was discovered that even when the supply to the coolant shaft originates asymmetrically from only one side, by means of correspondingly positioned guide elements that redirect, at least partially, the flow initially directed circumferentially along the coolant shaft to a radial flow toward the winding overhang in each example, uniform distribution of air to individual regions of the winding overhang is possible, particularly since the heat exchanger, usually embodied as an air-to-water heat exchanger, is typically located beneath the laminated stator core. The cooling fluid also reaches the side of the winding overhang facing away from the inflow side into the coolant shaft, and the side is also cooled, in particular to avoid the formation of hot spots in this region.

[0007] In this type of machine, the rotor shaft is typically oriented roughly horizontally, or the machine is embodied as a horizontal machine; however, the rotor shaft can certainly be positioned at an angle to the horizontal, and especially vertically.

[0008] After heat absorption in the winding overhang, the return channel through which the cooling fluid flows back to the heat exchanger can extend, for example, through the stator, and particularly through the laminated stator core.

[0009] Therefore, the cooling fluid typically forms a continuous circulating flow within the machine between the winding overhang and the heat exchanger to transport heat lost in the winding overhang region and, in some cases, heat lost in the laminated core region, from the winding overhang to the heat exchanger and, through the heat exchanger, to the outside of the machine.

[0010] Preferably, the guide element is oriented approximately radially. By oriented the guide element along the radial direction, preferably embodied as a plate, particularly good redirection of the tangential inflow into the coolant shaft to a radial flow in the direction of the winding overhang can be achieved.

[0011] Here, the terms radial and circumferential should be understood in the sense of the cylindrical coordinate system of the rotor of a machine, with the circumferential direction corresponding to the possible directions of rotation of the rotor around the rotor axis.

[0012] A portion of the flow that is redirected by the guide element into a radial flow toward the winding overhang will therefore have a larger velocity component toward the rotor axis and a larger velocity vector after the redirection than before the redirection. In the sense of cylindrical coordinates, this portion of the flow, or the corresponding flow volume, will therefore have a larger velocity component in the negative radial direction and a smaller velocity component in the circumferential direction, or opposite to the circumferential direction, after the redirection than before the redirection.

[0013] It is preferably defined that the outer surface is embodied, at least partially, as a surface of rotation approximately by the rotor axis, particularly as an outer cylindrical surface or an outer conical surface. As a result, the approximately radial inflow into the coolant shaft can be redirected, in a particularly efficient manner, to a flow that partially spreads circumferentially by a fan typically positioned on the side of the winding overhang, which may also be called the inflow side, and this flow also reaches the side of the winding overhang opposite the inflow side in order to cool a portion of the winding overhang as well.

[0014] Thus, the flow of the cooling fluid is redirected to a flow that spreads approximately tangentially or circumferentially along the outer surface of the coolant shaft, which is rotationally symmetric with respect to the rotor axis, and the circumferentially spreading flow can then be redirected by guide elements to a radial flow in individual regions of the winding overhang in order to cool the winding overhang in the most uniform possible manner. In this context, it is particularly beneficial if, in the region of the winding overhang located opposite the inlet side, individual guide elements each redirect approximately equal portions of the circumferentially spreading flow radially, and thus individual guide elements in a region redirect approximately equal portions of the circumferentially directed flow, or shorten approximately equal portions of the circumferentially directed flow that flow inward, respectively.

[0015] Preferably, the guide elements are specified to be positioned at approximately equal distances from the rotor axis. The guide elements may be embodied, for example, as guide plates positioned in ventilation holes, which may be part of the generator housing. However, the guide elements may also be elements connected to the winding overhang, particularly connecting towers, which are suitable for at least partially redirecting the flow toward a radial flow toward the winding overhang.

[0016] It has been found that distributing 10 to 100, and especially 30 to 60, guide elements around the perimeter is effective. As a result, particularly uniform distribution of the fluid flow circulating within the machine, typically between the heat exchanger and the winding overhang, to individual parts of the winding overhang can be achieved.

[0017] In principle, the machine includes two winding overhangs, each cooled with a cooling fluid. Preferably, the cooling fluid is defined to move into the stator through an air gap after passing through the winding overhangs, then move radially outward through ventilation slots in the laminated stator core, absorbing heat from the laminated stator core in the process, and then the cooling fluid moves back to the heat exchanger and fan, which may include one or more fan devices, in particular one or more axial or radiant fans. The cooling fluid thus circulates along a circumferential flow path, typically from the heat exchanger through the fan to the winding overhangs, to the stator, and back to the heat exchanger.

[0018] This is particularly preferable if it is specified that each cooling fluid circulating in the machine intersects with one of the winding overhangs in order to cool the winding overhang particularly well. This type of machine is also called a continuous aeration machine.

[0019] Typically, the guide elements are specified to be spaced apart from the outer surface. Thus, the flowing fluid is transported along the flow path from the inlet side to the region of the winding overhang further away, through a clear flow cross-section between the outer surface and the guide elements, with a portion of the flow simultaneously being redirected radially toward the winding overhang region via the individual guide elements. In this way, uniform ventilation of individual portions of the winding overhang is possible, along with a simple configuration design, since the volumetric flow rate flowing radially outward of the guide elements is substantially unaffected by the guide elements, and the effect of the guide elements can therefore be strictly limited. A defined portion of the volumetric flow rate moving circumferentially in the coolant shaft can therefore be shortened and redirected radially inward in the targeted manner using the guide elements.

[0020] This is beneficial if the guide elements have different spacings that decrease particularly continuously from the outer surface, and the guide elements have smaller spacings from the outer surface as the distance from the heat exchanger increases in the direction of flow. Thus, as the distance from the heat exchanger increases in the direction of flow, i.e., along the direction of flow in the coolant shaft, preferably by approximately equal magnitude from one guide element to the next, for example, increasing radially from 1 mm to 20 mm from one guide element to the next, the clear flow cross section between the outer surface and the guide elements positioned on the coolant shaft decreases. As the distance from the heat exchanger increases in the direction of flow, this can be realized forward, for example, by guide elements that extend longer radially, and such guide elements can be embodied, for example, to have an approximately constant cross-sectional area in the axial direction.

[0021] Preferably, the guide element extends axially over a length corresponding to the length of the winding overhang and / or the axial length of the coolant shaft.

[0022] For example, the guide element may be embodied as a plate, or more particularly, as an approximately cubic shape, with narrow sides extending approximately radially and parallel to the rotor axis, so that the surface of the guide element having the largest surface area is oriented approximately perpendicular to the circumferential direction in order to generate a particularly effective change of flow direction.

[0023] By using guide elements embodied to have different radial lengths, in particular, nearly equal volumetric flow rates are shortened or redirected radially inward toward the winding overhang at each guide element, thereby achieving particularly uniform cooling of the winding overhang around it in a forward-looking and simple manner. In particular, this prevents downstream guide elements positioned after upstream guide elements from generating no or insufficient radial volumetric flow rate redirection due to the shadowing effect of the upstream guide elements.

[0024] It is particularly preferable that the clear flow cross section between the outer surface and the guide elements decreases in a continuous manner from one guide element to the adjacent guide element as the distance from the heat exchanger in the direction of flow increases in at least several regions. If the coolant shaft is embodied in a roughly annular manner in at least several regions, i.e., preferably, with an essentially constant distance from the rotor axis to the outer surface, then a correspondingly smaller gap can be realized between the outer surface and the guide elements along the direction of flow by guide elements having a greater radial extension as the distance from the heat exchanger increases in the direction of flow, and so that at approximately equal distances from the rotor axis, the guide elements protrude more radially outward into the coolant shaft as the distance from the heat exchanger increases in the direction of flow. Thus, as the distance from the heat exchanger increases, the guide elements preferably extend more radially outward or into the coolant shaft, and so that the clear flow cross section along the direction of flow becomes smaller.

[0025] As an alternative to, or in addition to, guide elements of different lengths, a clear flow cross-section that decreases with respect to the distance from the heat exchanger in the direction of flow can, of course, also be achieved by the cross-section of the coolant shaft that decreases along the direction of flow, in particular, a coolant shaft that is embodied in an approximately helical shape in at least some regions.

[0026] It is therefore readily possible to use the dimensions of the Clearflow cross section, or the spacing between the guide elements and the outer surface, to divide the incoming flow into a first and second portion, which are essentially circumferentially oriented, the first portion being redirected radially inward to cool the winding overhang region assigned to each guide element, and the second portion of the flow being circumferentially oriented to cool the winding overhang region located downstream in the direction of the flow.

[0027] Regarding the specific structural embodiments of the coolant shaft and the guide element, it will be understood that numerical calculation methods can also be used for flow simulation.

[0028] The guide element can in principle be embodied in any desired way. It has been found to be effective if the guide element is embodied as a plate so as to achieve a forward-facing, simple and at the same time mechanically stable design. The guide element can be formed by elements fixed to the coolant shaft and / or fixed to the winding overhang, in particular by a modified connection tower connected to the winding overhang, or by a guide plate arranged on the coolant shaft which is welded or screwed, for example, together with a part of the housing forming the coolant shaft.

[0029] It can also be specified that the guide element can be detachably attached and fixed in place at different positions of the coolant shaft, and in particular can be rotated or pivoted in order to enable fine adjustments to be easily carried out on site.

[0030] It has been shown that if at least some of the guide elements include a rounded edge at the end delimiting the clearance flow cross-section between the outer surface and the guide element, preferably on the discharge side, a particularly uniform and effective cooling of the winding overhang can be achieved. In this way, the turbulent flow on the discharge side which has a negative impact on the direction change is reduced or avoided. For example, the guide element can be embodied as a plate and can include a rounding with a radius of 0.5 mm to 10 mm at the radially outer edge on the discharge side, i.e. on the side located downstream.

[0031] In particular on the connection side of the generator, it can be规定 that the guide element is formed by an element fixed and connected to the winding overhang, in particular by a connection tower. In a connection tower made of insulating material, the electrical connection is generated between the individual conductors of the stator of the winding overhang, in particular on the side of the generator referred to as the connection side, and thus, for example, the connection towers are positioned at regular intervals around the winding overhang and are thus suitable for use as guide elements at the same time.

[0032] For this purpose, the connection tower can include plate-shaped elements oriented approximately in the radial direction or can be formed by correspondingly oriented elements that extend into the coolant shaft.

[0033] The machine according to the invention can in principle also be embodied in the case of no ventilation to the outside, where the flow is generated only by the rotation of the rotor. However, it is preferably规定 that a fan, in particular an axial fan or a radial flow fan, is provided, and by means of the axial fan, a flow of fluid, in particular air, from the heat exchanger through the coolant shaft to the winding overhang and back to the heat exchanger can be generated in the machine. The fan can be embodied, for example, to achieve a volume flow rate of 6 m per second at a pressure difference of 2000 Pa and an air density of 1.2 kg / m 3 but, of course, the specific embodiments depend on the structural design of the machine. 3

[0034] In the example of a rotating electric machine, which can typically be embodied as a motor or generator, for example, two winding overhangs are provided to the stator, where, in principle, separate fans or other devices for increasing pressure, and possibly also separate heat exchangers, may also be provided for each winding overhang. However, it is preferable that the stator includes two winding overhangs, each winding overhang connected to the fan and the heat exchanger via separate flow paths. As a result, in particular, the fan and heat exchanger may include, for example, two or three separate fans and heat exchangers, respectively, so that a simple design and redundancy can be easily achieved, and thus sufficient cooling can be ensured even in the event of a fan or heat exchanger failure.

[0035] To achieve a specific and uniform distribution of flow volume to individual regions of the winding overhang, it is preferably assumed that separate flow paths are provided for the upper region of the winding overhang and for the lower region of the winding overhang. Typically, the upper region of the winding overhang is at a greater distance from the heat exchanger, or the flow path from the heat exchanger to the upper region of the winding overhang is longer than the flow path from the heat exchanger to the lower region of the winding overhang. Thus, a uniform distribution can be achieved, for example, when the cross-sectional area of ​​the flow path connecting the heat exchanger to the lower region of the winding overhang is smaller than the cross-sectional area of ​​the flow path connecting the heat exchanger to the upper region of the winding overhang, and therefore the corresponding pressure loss is greater, via correspondingly separated flow paths. Separation of volumetric flow by a fan, which may include one or more fan devices such as an axial flow fan, can be achieved, for example, by a separation element in a region located downstream of the fan.

[0036] In addition, the partial volume flow splitting to the left and right may also be advantageous, for example, with respect to the upper region of the winding overhang, or to the region of the winding overhang that is further from the inflow side.

[0037] Furthermore, the division of the volumetric flow preferably occurs in separate portions relating to the winding overhangs, namely, one portion relating to the winding overhang on the connected side of the machine and one portion relating to the winding overhang on the unconnected side of the machine, so that the volumetric flow of the cooling fluid moved by the fan or in the machine is typically divided into four partial volumetric flows, by which the two winding overhangs are vented individually at the top and bottom, respectively, and the four partial volumetric flows can then move through the air gap and back to the heat exchanger and fan through the vent slots in the stator. In particular, if there is also a division of the volumetric flow relating to the left-hand region and the right-hand region of the winding overhang, then a division into more than four partial volumetric flows, for example, six or eight partial volumetric flows, may also be advantageous. [Brief explanation of the drawing]

[0038] Additional features, advantages, and effects of the present invention follow from the exemplary embodiments illustrated below, in the drawings referenced therein:

[0039] [Figure 1] The cross-sectional view shows a machine according to the present invention. [Figure 2] Details of a machine according to the present invention are shown below. [Figure 3] Further details of the machine according to the present invention are shown below. [Modes for carrying out the invention]

[0040] Figure 1 shows an electric machine according to the present invention in a cross-sectional view. As can be seen, the rotating electric machine, embodied as a motor generator, is in this case embodied as a horizontal machine, which may be used, for example, in a hydroelectric power plant and therefore includes a horizontal rotor shaft 3. The machine according to the present invention may, however, also be embodied as a vertical machine. The illustrated machine is embodied as an externally ventilated machine, with a fan 5 positioned below the stator. The fan 5 can be used to obtain a continuous fluid flow in the machine, thereby dividing air or a different cooling fluid into a plurality of partial volume flows, which are transported from the fan 5 through vents to the winding overhang of the stator along four schematically illustrated flow paths 4, which are transported separately to the upper and lower regions of the winding overhang, where heat is released to the cooling fluid by the winding overhang 1.

[0041] Through the air gap 10 between the rotor 13 and the stator, the cooling fluid then reaches the vent slots located in the stator, and through these vent slots, the cooling fluid flows radially outward through the laminated stator core 14, thereby absorbing heat from the stator. The cooling fluid then flows back to the fan 5 through the heat exchanger 6, which in this case is embodied as an air-to-water heat exchanger 6, where the cooling fluid releases heat. The return paths for all four partial volume flows are therefore connected in this case through the air gap 10 and the laminated stator core 14.

[0042] As can be seen in Figure 1, the entire machine is ventilated to the outside by a fan 5 located below the stator, where the fan 5 can of course also be formed by multiple fan devices, such as eight axial fans or radial fans.

[0043] As shown in the figure, the entire air through which the fan 5 acts is preferably guided over the winding overhang, thus achieving continuous cooling, and thereby providing a continuously cooled horizontal machine.

[0044] In the fan outlet region, the volumetric flow rate for the winding overhang 1 on the connected side of the machine is divided into two parallel branches, similar to the volumetric flow rate for the winding overhang 1 on the unconnected side of the machine, where one branch supplies cooling fluid to the upper region of the winding overhang and the other branch supplies it to the lower region of the winding overhang. This is advantageous in this case, especially because the inlet side from which the cooling fluid is transported to the winding overhang 1 is located here at the bottom of the stator. Thus, the flow path 4 to the lower region of the winding overhang 1 is correspondingly shorter than the flow path 4 for the cooling fluid to the upper region of the winding overhang 1. By selecting appropriate cross-sections for the flow paths 4 to the upper and lower regions, very uniform flow to these regions separated from the fan 5 by different distances, and therefore cooling of these regions, can still be ensured. In particular, if fan 5 were located on the side of the stator rather than at the bottom, it would be understandable that the division of winding overhang 1 into left-hand and right-hand regions would also be beneficial.

[0045] Furthermore, a division occurs into two winding overhangs of the stator, namely winding overhang 1 on the connected side of the stator and winding overhang 1 on the unconnected side of the stator. The volumetric flow rate of the cooling fluid circulating within the machine is therefore divided into four partial volumetric flows, as can be seen in Figure 1, based on the individual flow paths 4 to the winding overhangs.

[0046] Figure 2 shows a portion of the connection side of the machine illustrated in Figure 1. As can be seen, a portion of the machine housing 2 includes a coolant shaft 17 through which the cooling fluid is guided by a fan 5 to a winding overhang, which is schematically illustrated in the lower region.

[0047] Furthermore, in relation to the upper region of the winding overhang 1, a division of the volumetric flow occurs into a partial volumetric flow with respect to the right-hand region of the winding overhang 1 and a partial volumetric flow with respect to the left-hand region of the winding overhang 1. Figure 2 shows the ventilation of one of these two regions, for example, the left-hand region. The mechanical region of the second region is therefore configured symmetrically with respect to the vertical central plane of the region shown in Figure 2, and thus the flow in the upper region of the winding overhang 1 of the region spreads in the opposite manner to that of the region shown.

[0048] The illustrated portion of housing 2 includes a substantially rotationally symmetric internal region in which a winding overhang 1 (not shown) is located. Since fan 5 is located below winding overhang 1, as can be seen, the flow path 4 from fan 5 to the upper region of winding overhang 1 is longer than the flow path 4 to the lower region of winding overhang 1. Nevertheless, separate flow paths 4 are provided, on the one hand, from fan 5 to the lower region of winding overhang 1 and to the upper region of winding overhang 1, in order to achieve the most uniform possible cooling of the individual regions of winding overhang 1. The corresponding division is realized in this case by a separation device 7, which can be embodied, for example, as a plate in the coolant shaft 17.

[0049] On the other hand, the guide element 11 is located on the coolant shaft 17 and is oriented substantially radially to redirect the flow in the coolant shaft 17 to one portion each, in order to apply cooling air or a different fluid radially to the winding overhang 1. On the illustrated connection side, the guide element 11 is formed by a connection tower to which the individual bars of the stator winding overhang 1 are electrically connected on the connection side.

[0050] On the non-connected side, which is located opposite to the connected side, the guide element 11 may be formed by a guide plate positioned on the coolant shaft 17.

[0051] Figure 3 shows in detail the upper region of the coolant shaft 17 shown in Figure 2, which has an outer surface that is approximately rotationally symmetric with respect to the rotor shaft 3 of the generator, and thus the coolant shaft 17 is realized here in a substantially arc shape.

[0052] To achieve uniform cooling of the winding overhang 1, the guide elements 11 extend radially outward as the distance from the heat exchanger 6 increases in the direction of flow, as depicted, and therefore, at each guide element 11, a further area of ​​flow spreading circumferentially 9 in the coolant shaft 17 is shortened or redirected inward into the radial flow applied to each region of the winding overhang 1 to cool the winding overhang 1.

[0053] Figure 3 shows only the portion of the coolant shaft 17 for venting the left-hand portion of the winding overhang 1, as in Figure 2, with the corresponding right-hand portion being symmetrically realized. Thus, in the right-hand portion, which is not shown, the guide element 11 also extends radially outward as the distance from the heat exchanger 6 increases in the direction of flow, and the flow in the right-hand portion spreads in the opposite direction to the shown flow direction.

[0054] The clear flow cross section 12 between the guide element 11 and the outer surface thus decreases continuously from one guide element 11 to the adjacent guide element 11 along the direction of flow, and the direction of flow can be directed both in the circumferential direction 9 and opposite to the circumferential direction 9. As a result, it is easily ensured that each of the guide elements 11 redirects a portion of the flow into an inward radial flow toward the winding overhang 1, and that shadowing of the downstream guide element 11 is compensated for.

[0055] The individual guide elements 11 are thus separated from their respective outer surfaces, as depicted, thereby ensuring that only a portion of the volumetric flow rate flowing in the circumferential direction 9 is redirected inward in the radial direction 8, and thus the volumetric flow rate is also left for the portion of the winding overhang 1 located downstream in the direction of flow. To visualize this, the velocity vectors 16 of the cooling fluid or coolant are illustrated on the coolant shaft 17.

[0056] Furthermore, the guide element 11 may be embodied in a rounded shape at its radially outer end, i.e., the discharge side. The rounding 15 of the side edge of the guide element 11 positioned downstream may thereby have a radius of, for example, 1 mm to 20 mm. As a result, turbulence that could have a negative effect on direction changes is avoided in this region.

[0057] The machine embodied in the present invention provides particularly uniform cooling to the winding overhang region, thereby effectively avoiding hot spots that could cause damage.

Claims

1. An electromachinery, particularly a generator, comprising a stator including a winding overhang, a rotor rotatably positioned in the stator around a rotor axis, and a heat exchanger, the heat exchanger being fluidly connected to the winding overhang via a coolant shaft, the coolant shaft being positioned radially outward from the winding overhang, extending at least partially substantially circumferentially, and radially demarcated by its outer surface, so that the winding overhang can be cooled by a continuous flow of fluid covering the heat exchanger and the winding overhang, and a plurality of guide elements dispersed along the circumferential direction are provided to the coolant shaft to at least partially redirect the circumferentially oriented fluid flow in the coolant shaft into a radial flow toward the winding overhang, and to distribute the flow to a plurality of regions of the winding overhang.

2. The electric machine according to claim 1, wherein the guide element is oriented approximately in the radial direction.

3. The electromachine according to claim 1 or 2, wherein the outer surface is at least partially embodied as a surface of rotation by the rotor shaft, and more particularly as an outer cylindrical surface or an outer conical surface.

4. The electromachine according to any one of claims 1 to 3, wherein the guide elements are arranged at substantially equal intervals from the rotor shaft.

5. The electromachine according to any one of claims 1 to 4, wherein 10 to 100, particularly 30 to 60, guide elements are arranged in a distributed manner around the perimeter.

6. The electric machine according to any one of claims 1 to 5, wherein the guide element is arranged at a distance from the outer surface.

7. The electromachine according to claim 6, wherein the guide elements are spaced at different intervals from the outer surface, and the guide elements are spaced at smaller intervals from the outer surface as the distance from the heat exchanger increases in the direction of flow.

8. The electromachine according to any one of claims 1 to 7, wherein the clear flow cross section between the outer surface and the guide elements decreases in a series of regions, from one guide element to the next, as the distance from the heat exchanger in the direction of flow increases.

9. The electric machine according to any one of claims 1 to 8, wherein the guide element is embodied in the form of a plate.

10. The electromachine according to any one of claims 1 to 9, wherein at least some guide elements include rounded edges, preferably on the discharge side, at the ends that divide the clear flow cross section between the outer surface and the guide elements.

11. The electric machine according to any one of claims 1 to 10, wherein the guide element is formed by an element fixed to and connected to the winding overhang.

12. An electromachine according to any one of claims 1 to 11, wherein a fan, in particular an axial fan, is provided, and by the axial fan, a flow of fluid, in particular air, from the heat exchanger through the coolant shaft to the winding overhang and back to the heat exchanger is generated in the electromachine.

13. The electromachine according to claim 12, wherein the stator includes two winding overhangs, each winding overhang being connected to the fan and the heat exchanger via separate flow paths.

14. The electromachine according to any one of claims 1 to 13, wherein separate flow paths are provided for the upper region of the winding overhang and the lower region of the winding overhang.

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