Wound rotor for rotating electrical machine

Abstract

A wound rotor (2) for a rotary electric machine (1) comprises:-salient poles, each salient pole comprising a pole body and two pole shoes arranged one on each side of the pole body at a free end of the pole body,-at least two pairs of slots (9; the invention relates to a salient pole (1) comprising:-a pair of slots (10), two of which are arranged one on each side of the pole body of the salient pole, two adjacent slots of the salient pole being separated by a lug (11), and-at least two coils (12) per salient pole, each coil (12) being housed in a pair of slots of the salient pole.

Description

Technical Field

[0001] The present invention relates to rotors of rotating electrical machines and more particularly, but not exclusively, to wound rotors of industrial alternators. Background Art

[0002] In rotating electrical machines, such as the one disclosed in EP 0 085 619 , heating of the coils is necessarily involved during operation of the machine.

[0003] To cool the rotor, it is known practice to place cooling channels directly in the rotor and use a fluid present directly in the motor. This fluid (usually air) exchanges heat with the solid components of the rotor by convection. To this end, the air can be agitated by the rotational movement of components fastened to the rotor. However, this method of cooling is relatively inefficient for enclosed motors due to the low velocity of the air.

[0004] Therefore, there is a need to further improve the cooling system and prevent the rotor from magnetic saturation without limiting the performance of the motor. Summary of the Invention

[0005] The present invention aims to meet this need and, for this purpose, according to one of its aspects, uses a wound rotor for a rotating electrical machine, the wound rotor comprising:

[0006] - salient poles, each comprising a pole body and two pole shoes, the two pole shoes being arranged one on each side of the pole body at the free end of the pole body,

[0007] at least two pairs of grooves made in one salient pole, the two grooves of a pair being arranged one on each side of the pole body of the salient pole, two adjacent grooves of the salient pole being separated by a lug, and

[0008] - At least two coils per salient pole, each coil being housed in a pair of slots of the salient pole.

[0009] The invention makes it possible to improve the thermal performance of the rotor and to reduce the heating of the coils of the rotor, in particular for a given copper volume.

[0010] The maximum temperature rise usually occurs in the middle of the slot, where the copper is concentrated. Dividing the slot into at least two slots (each slot can be smaller) separated by a lug allows for two separate hot spots, each of which is not too hot individually. Thus, by avoiding hot spots located in copper blocks with large volumes, the cooling of the coil can be improved.

[0011] Furthermore, the lugs also make it possible to increase the heat exchange surface and improve cooling.

[0012] In addition, mechanical properties can be improved.

[0013] The invention also makes it possible to reduce the current required to supply power for a given operating point. In situations where available volume is limited (for example, in the railway sector) but the required performance level is high, there is a risk that the magnetic stack and the shaft will reach saturation with the same amount of copper. Therefore, to achieve a slight increase in the magnetic field (and therefore the induced current), it may be necessary to significantly increase the current intensity.

[0014] Therefore, the power density of the resulting electric machine can be improved.

[0015] The presence of the lugs provides an additional path for the magnetic field and makes it possible to reduce saturation in both the poles and the shaft. Reduction of shaft saturation makes it possible to prevent magnetic dispersion in the shaft, thus reducing the ampere per turn necessary for the motor to operate.

[0016] The rotor advantageously has a reduced volume while providing sufficient thermal power. The rotor according to the invention can be used in particular in the railway sector, on or under railway carriages. The issue of floor space is crucial for this application.

[0017] The invention applies to a rotor of a rotating electrical machine, in particular having a rotational speed of, for example, between 0 and 10,000 revolutions per minute for a power output between 0 MW and 2 MW.

[0018] The rotor may include a shaft extending along a rotation axis, with rotor magnet blocks including salient poles arranged on the shaft.

[0019] The shaft may be made of a magnetic material, which makes it possible to improve the electromagnetic performance of the rotor.

[0020] As a variant, the rotor comprises a non-magnetic shaft. The shaft may be made at least partially of a material from the following non-limiting list: steel, stainless steel, titanium or any other non-magnetic material.

[0021] Each coil surrounds the pole body of a corresponding salient pole. Each coil may include at least one wire wound around the pole. The wire may have a flat cross-section, such as a rectangular or substantially rectangular shape. The wire may be made of copper.

[0022] Each pair of slots can have a coil inserted into it. The rotor's coils can be arranged in a concentrated manner in the slots, i.e. each coil can be wound around a single salient pole of the rotor. The coils can be inserted individually or simultaneously.

[0023] The coils of the same salient pole of the rotor can be connected in series or in parallel.

[0024] The coil comprises an electrical conductor. The electrical conductor may have a circular or flat cross section, but preferably has a polygonal, in particular rectangular, cross section. This allows for a larger contact surface with the imaginary wedge.

[0025] When the conductors have a circular cross-section, they can be arranged in a hexagonal stack in the slots. When the conductors have a flat cross-section, they can be arranged in one or more rows in the slots. Optimizing the stacking allows for a larger number of conductors to be arranged in the slots while simultaneously reducing the effective area of ​​the slots, thereby achieving a more powerful rotor for the same volume. The coil can contain one or more (e.g., one, two, three, or four) rows of conductors.

[0026] Disclosure of the Invention

[0027] The rotor may comprise two salient poles. The rotor may comprise exactly two salient poles. As a variant, the rotor may comprise more than two salient poles, in particular an even number of salient poles, for example two or four salient poles.

[0028] A salient pole may include a first pair of slots, both slots of the first pair being laterally delimited by a lug and a pole shoe of the corresponding salient pole.

[0029] Each salient pole may include a first pair of slots, two slots of the first pair of slots being laterally delimited by a lug and a pole shoe of the corresponding salient pole. Each salient pole may accommodate a first coil accommodated in the first pair of slots. The first coil is proximal to the pole shoe.

[0030] One salient pole may comprise a second pair of slots, the two slots of the second pair being laterally delimited by a lug and an interpolar region E or another lug of the corresponding salient pole.

[0031] Each salient pole may comprise a second pair of slots, the two slots of the second pair being laterally delimited by a lug and an interpolar region E or another lug of the corresponding salient pole.

[0032] The interpolar region E is a region of the rotor extending between two circumferentially consecutive salient poles. The rotor may include two or more interpolar regions E, each interpolar region extending between two consecutive salient poles. In one embodiment, the rotor includes two interpolar regions E.

[0033] The interpolar region E may include an internal cooling channel in which a coolant (e.g., air or water) may circulate. The interpolar region may include one or more channels, in particular an even number (e.g., two, four, or eight) of channels. Each channel may have a rectangular or substantially rectangular cross-section.

[0034] One or more interpolar regions E may comprise a surface facing the air gap of generally concave shape. This concavity makes it possible to increase the heat exchange and thus promote the cooling of the rotor.

[0035] The width hi of a slot i may be defined as corresponding to its lateral dimension measured parallel to the polar axis of the salient pole.

[0036] Depth l of groove ii It can be defined as the dimension corresponding to its perpendicular to the polar axis of the salient pole.

[0037] The length of a slot may be defined as corresponding to its dimension measured parallel to the axis of rotation X of the rotor.

[0038] The slots can have the same size or different sizes. The two slots in a pair of slots can have the same size. Two adjacent slots can have the same size or different sizes.

[0039] For example, the grooves of the first pair of grooves may have the same width as the grooves of the second pair of grooves. As a variant, the widths may be different.

[0040] Additionally, the grooves of the first pair of grooves may have a smaller depth than the grooves of the second pair of grooves.The grooves may be symmetrical or asymmetrical to each other with respect to the pole body.

[0041] The grooves of the first pair of grooves may have a smaller depth than the grooves of the second pair of grooves.

[0042] When viewing the groove in cross section, the groove depth is measured in the middle of the groove. If the groove depth is variable, the measurement is taken in the plane that cuts the groove in half in cross section.

[0043] The dimensions of the slots are chosen so as to manage the wedging of the coils, the amount of copper necessary, the level of mechanical stress and the heat exchange in the rotor.

[0044] The presence of paired slots makes it possible to provide an additional degree of freedom in the choice of slot dimensions, which makes it possible to better manage the passage of the pole and axis fluxes.

[0045] Each salient pole may include exactly two pairs of slots.

[0046] The lug separating two adjacent slots may have a width between 6 mm and 20 mm, or between 6 mm and 15 mm, better still between 8 mm and 9 mm.

[0047] The width e of the lug is measured perpendicularly to the direction of extension of the lug in a plane perpendicular to the axis of rotation X of the rotor.

[0048] The length l of the lug is measured in a plane perpendicular to the axis of rotation X of the rotor, parallel to the direction of elongation of the lug and perpendicular to the polar axis of the salient pole.

[0049] The width e of the lug may be sufficient to ensure satisfactory mechanical strength.

[0050] The width e of the lug may be small enough to leave sufficient slot width for the adjacent slot.

[0051] Preferably, the width e of the lug is smaller than its length l.

[0052] The lugs may be rectangular or trapezoidal. They may also take other forms, such as a triangle extending towards the air gap.

[0053] The width e of the lug is related to the effective height H of the pole pu The ratio between the effective height H of the pole can be between 0.12 and 0.19. pu All salient poles of the rotor may have the same effective pole height H pu .

[0054] The width e of the lug and the effective pole height H pu The ratio between can be between 0.11 and 0.35 or between 0.12 and 0.13. This range of values ​​reflects the criteria that the lugs must meet: thin enough to allow a sufficient amount of winding to provide the required performance, but thick enough to have sufficient mechanical strength during operation.

[0055] It is also possible to define a pole head width L corresponding to the distance between the two pole shoes of the salient pole. p All salient poles can have the same pole head width L p .

[0056] The width of the pole body of the salient pole aligned with a pair of slots i can also be defined for the salient pole and expressed as L cp,i The width of the pole body of the salient pole aligned with the first pair of slots can be expressed as L cp,1 , and the width of the pole body aligned with the second pair of slots can be expressed as L cp,2 .

[0057] A ratio between a width of a pole body of the salient pole aligned with the second pair of slots and a width of the salient pole aligned with the first pair of slots is between 1 and 1.15.

[0058] The ratio between the width of the pole body of the salient pole aligned with the second pair of slots and the width of the pole body of the salient pole aligned with the first pair of slots can be between 1.0 and 1.14, or between 1.01 and 1.13, preferably between 1.02 and 1.12. This makes it possible to advantageously divide the amount of coil strands in the slots for better heat distribution during operation.

[0059] The width L of the pole body aligned with a pair of slots cp,i (In particular, the width L of the pole body aligned with the first pair of slots cp,1 ) and the pole width L p The ratio between them is between 0.5 and 0.55.

[0060] The width L of the pole body aligned with a pair of slots cp,i(In particular, the width L of the pole body aligned with the first pair of slots cp,1 ) and the pole width L p The ratio between φ and φ may be between 0.51 and 0.54 or between 0.52 and 0.53. These limits of the ratio make it possible to create sufficient space to accommodate the coil while ensuring sufficient mechanical strength.

[0061] The rotor may comprise at least one wedge closing at least one slot over at least a portion of its length. The wedge makes it possible to retain the coil in the slot against the action of centrifugal forces.

[0062] The wedge closes the slot over at least a portion of its length measured along the axis of rotation X of the rotor. It closes the slot over a portion that is strictly less than 100% of the slot length, better still less than 80% of the slot length, or less than 50% of the slot length, or better still less than 25% of the slot length, which makes it possible to ensure improved cooling of the coil.

[0063] The slot may be closed by a single wedge. As a variant, the slot may be closed by a plurality of wedges distributed over the length of the slot along the axis of rotation X of the rotor.

[0064] The slot can be closed by two or more (e.g., three or more) wedges. The wedges can be evenly or unevenly distributed over the entire length of the slot. Two consecutive wedges can have a constant or non-constant spacing. The spacing between two consecutive wedges can be between 10% and 80% of the slot length, more preferably between 20% and 70% or between 30% and 60% of the slot length.

[0065] The one or more wedges may close the slot over a portion of the slot length that is strictly less than 100% of the slot length. The one or more wedges may close the slot over a portion that is strictly less than 100% of the slot length, better still less than 80% of the slot length, better still less than 50% of the slot length, better still less than 25% of the slot length.

[0066] The wedges may cover the coils along the axis of rotation X only over a portion of the rotor, for example a portion less than 80%, or less than 50%, or better still less than 25%.

[0067] The presence of a plurality of wedges arranged in series makes it possible to provide improved coil retention while allowing air circulation for improved cooling.

[0068] The width of at least one wedge or all wedges may be less than 50% of the slot length, better less than 40% of the slot length, or less than 30% of the slot length, or even less than 20% of the slot length. The width of the wedge is measured along the axis of rotation of the rotor.

[0069] A wedge having a relatively small width advantageously makes it possible to reduce the mechanical stresses thereon.The rotor can be used at higher speeds.

[0070] When viewing the wedge along the axis of rotation X of the rotor, the wedge or wedges may follow the outer contour of the rotor.

[0071] The wedge may be polygonal, in particular rectangular, when viewed from the front.

[0072] The wedge may be slid into the slot and secured to the edge of the slot, such as by a dovetail joint.

[0073] The lugs and wedges provide a circulation path for the magnetic field, thereby making it possible to reduce magnetic saturation in the shaft and magnetic stack.

[0074] The wedge may have a notched surface in order to ensure improved retention of the coil when it has, for example, a rectangular cross section.

[0075] When viewing the wedge laterally, the wedge may follow the outer contour of the rotor.

[0076] The wedges can have an inclination angle relative to the axial end axis of the salient poles. This angle can be adjusted so that the wedges extend the outer profile of the rotor and reduce irregularities in the equipment. According to this aspect, the radial ends of the lugs do not extend beyond the wedges.

[0077] The wedges may be made by molding and / or machining.

[0078] The wedge may be of one piece.

[0079] The wedge may comprise or consist of a metallic material such as aluminium or an electrically insulating material, in particular a filled or unfilled thermoplastic. The use of such a material makes it possible to dispense with an electrically insulating material, for example arranged in the form of a thin sheet, between the wedge and the coil.

[0080] The rotor according to the invention may comprise an electrically insulating material, in particular in the form of a thin sheet, which is arranged between the wedges and the coils in which they are located. This makes it possible to electrically insulate the wedges from the coils, in particular when the wedges comprise or consist of a metallic material.

[0081] The rotor may include cooling channels extending parallel to the axis of rotation of the rotor.

[0082] The number of cooling channels may be two, four, six or eight, or even twelve or sixteen. The cooling fluid may preferably be air, but is not limited thereto. Depending on the desired rotor cooling, each interpolar region E may have a greater or lesser number of cooling channels running along the rotor.

[0083] These channels can run along the entire length of the rotor. They can be continuous or discontinuous along the rotor. When the channels are discontinuous, the coolant passes alternately inside and outside the channels in the interpolar region E, which creates turbulence that favors convective exchange.

[0084] The rotor may further include circular holes formed near the air gap and close to the surface of the salient poles for the dampers to pass through.

[0085] It may also comprise circular apertures made in the salient poles at the bottom of the slots, through which cylindrical steel bars may pass, which bars may be used to hold the coil heads.

[0086] Additionally, it may include one or more holes to reduce weight and allow it to balance.

[0087] The rotor's salient poles can be formed from an assembly of magnetic laminations. Each magnetic lamination can have all its poles integral. Each lamination can be cut from a magnetic steel sheet (e.g., 0.1 mm to 1.5 mm thick). Before the laminations are assembled in a stack, they can be coated on opposing sides with an electrically insulating varnish. Insulation can also be achieved by heat treating the laminations.

[0088] The rotor may include tie rods for securing the assembly of magnetic stacks.

[0089] The assembly can also be secured to the shaft of the motor by dovetail joints. Each pole piece can include a stack of magnetic laminations. The rotor block can include one or more holes to reduce the weight of the rotor, allow for balancing, or for assembling the rotor laminations that form the rotor block. The holes can accommodate tie rods that rigidly secure the laminations to each other.

[0090] The invention also relates, independently or in combination with the above, to a rotating electrical machine comprising a rotor as defined above.

[0091] The electric machine may also include an air cooling circuit. The rotating electric machine may in particular include a cooling circuit in which a coolant may circulate. The coolant may be, for example, air. The coolant may circulate in cooling channels of the cooling circuit, which may be formed in the interpolar region E.

[0092] The motor may include one or two fans so that forced air can circulate in the cooling channel. If the selected embodiment includes one or more fans, the one or more fans can be driven by the rotor to generate forced air circulation in the cooling channel.

[0093] The cooling circuit may, for example, further comprise an external water jacket in order to cool the air circulating in the rotor.

[0094] The motor may be multiphase. The rotational speed of the rotary motor may be between 1 rpm and 10,000 rpm, better between 100 rpm and 8,000 rpm, or even between 1,000 rpm and 5,000 rpm; the rotational speed is for example 3,000 rpm.

[0095] The electric machine may also include a stator, within which the rotor rotates.

[0096] The stator is a hollow cylinder into which the rotor is inserted. It can include slots distributed on its inner surface, facing the rotor, designed to accommodate the electrical conductors for the induction mechanism. When viewing the motor laterally, these slots can be evenly distributed radially.

[0097] The ratio between the diameter of the rotor and the outer diameter of the motor is between 0.58 and 0.63. The outer diameter of the motor corresponds to the diameter of the assembly comprising the shaft, rotor, and stator. The ratio between the diameter of the rotor and the outer diameter of the motor can be between 0.59 and 0.62, preferably between 0.60 and 0.61. Adherence to this ratio makes it possible to meet the requirements of a small footprint, which is particularly useful in the railway sector. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] The present invention will be more clearly understood by reading the following description of non-limiting exemplary embodiments of the invention with reference to the accompanying drawings, in which:

[0099] [ Figure 1 ] Figure 1 is a schematic partial cross section of a rotating electrical machine according to the invention having a stator and a rotor.

[0100] [ Figure 2 ] Figure 2 yes Figure 1 The cross section of the rotor has a wedge shape.

[0101] [ Figure 3 ] Figure 3 yes Figure 1 Cross section of the rotor without wedges.

[0102] [ Figure 4 ] Figure 4 is a variant embodiment of Figure 1 Similar view.

[0103] [ Figure 5 ] Figure 5 Another variant embodiment is shown. DETAILED DESCRIPTION

[0104] Figures 1 to 3A rotating electrical machine 1 according to the invention is shown. This machine 1 comprises a rotor 2 and a stator 3, separated by an air gap 4. The stator 3 is a hollow cylinder in which the rotor 2 is housed. It comprises slots 7 distributed over its inner contour, facing the rotor, and intended to accommodate the electrical conductors necessary for the induction mechanism. The rotor 2 is mounted on a shaft 5 that can rotate about its longitudinal axis, while the stator 2 is fixed relative to a housing (not shown here).

[0105] exist Figure 1 In the embodiment shown in FIG, the ratio between the diameter of the rotor 2 and the diameter of the electric machine 1 measured on the circumference of the stator 3 is 0.62.

[0106] The rotor 2 can be monolithic or, as in the embodiment illustrated here, consist of a plurality of stacked laminations held together by tie rods passing through holes 6. The laminations are magnetic, for example. The thickness of the laminations is between 0.1 mm and 1.5 mm.

[0107] The rotor 2 includes a diameter D a The rotor 2 comprises two salient poles. Each salient pole in turn comprises a pole body 19 of constant width in the present case and two pole shoes 17 arranged one on each side of the pole body at the free end. The distance between the two ends of the pole shoe 17 defines the pole head width L. p .

[0108] The first pair of grooves 9 is formed on each side of the pole body 19 of the salient pole. The second pair of grooves 10 is formed on each side of the pole body 19 of the salient pole. Each groove has a depth of l i .

[0109] The grooves 9 and 10 on the same side of the pole body 19 are separated by a lug 11 having a width e. The width e of the lug is approximately 9 mm. Figure 2 and Figure 3 In the case shown in FIG, its width is less than its length. The first pair of slots 9 is located between the pole shoe 17 and the lug 11, while the second pair of slots 10 is located between the lug 11 and the interpolar region E.

[0110] The width e of the lug 11 is related to the effective height H of the pole pu The ratio between them is between 0.1 and 0.15.

[0111] The slots are symmetrical to each other with respect to the pole body.

[0112] These slots are intended to house the coils 12 of the rotor 2 while separating them into two groups so as to limit the maximum temperature rise. The slots 9 and 10 each have a width hi and h2 which are equal in this embodiment.

[0113] The width L of the pole body 19 of the salient pole aligned with the second pair of slots 10 is cp,2and the width L of the pole body 19 of the salient pole aligned with the first pair of slots 9 cp,1 The ratio between them is 1.0.

[0114] The width L of the pole body 19 of the salient pole aligned with the first groove cp,1 With the pole width L P The ratio between them is 0.54.

[0115] The wedges 13 close the pairs of slots 9 and 10 and prevent the coils 12 from escaping due to centrifugal forces when the motor is running. Figure 3 Here, these wedges 13 follow the outer contour of the rotor in order to reduce irregularities of the device and maximize the space allocated to the coils 12 in the pairs of slots 9, 10.

[0116] In the present case, the wedge 13 is rectangular.

[0117] They close the slot over a portion of the slot length that is strictly less than 100% of the slot length.

[0118] The spacing between two consecutive wedges may be between 10% and 80% of the slot length.

[0119] Eight cooling channels 14, four being arranged on each side of the pole, are made in the interpolar region E. These channels 14 make it possible to circulate air, ensuring improved cooling.

[0120] The interpolar region(s) E comprise a surface facing the air gap having a concave shape, thereby promoting heat exchange and cooling of the rotor 2 .

[0121] The cross section of each channel 14 is substantially rectangular.

[0122] Circular holes 15 are made near the air gap, close to the surface of the salient pole, through which the damper can pass.

[0123] The rotor further comprises circular apertures 18 made in the salient poles at the bottom of the slots, through which cylindrical steel bars can pass, which bars can be used to hold the coil heads.

[0124] Figure 4 Another embodiment is shown which is similar to the embodiment in terms of the groove depths l1 and l2. Figures 1 to 3 The depth of the grooves in the first pair of grooves 9 is smaller than that in the second pair of grooves 10. As a result, the width of the pole body 19 varies, and the pole body width is different, L cp,1 Less than L cp,2 The lugs 11 are shorter, which advantageously enables an improvement in mechanical strength. The width L of the salient pole aligned with the second pair of slots 10 is cp,2and the width L of the salient pole aligned with the first pair of slots 9 cp,1 The ratio between them is greater than 1.0.

[0125] Figure 5 A further embodiment is shown which combines a number of 16 cooling channels with different depths l1 and l2 and therefore different pole body widths L cp,1 and L cp,2 slot.

[0126] The coil 12 is composed of an electrical conductor having a rectangular cross section.

[0127] The electrical conductors are arranged in four rows. This shape has been chosen to allow for optimal stacking and thus makes it possible to position the maximum number of electrical conductors.

Claims

1. A wound rotor (2) for a rotating electrical machine (1), comprising: - salient poles, each comprising a pole body (19) and two pole shoes (17), said two pole shoes being arranged one on each side of said pole body at the free end of said pole body, - at least two pairs of grooves (9; 10) made in a salient pole, the two grooves of a pair being arranged one on each side of the pole body (19) of the salient pole, two adjacent grooves of the salient pole being separated by a lug (11), and - at least two coils (12) per salient pole, each coil (12) being housed in a pair of slots of said salient pole.

2. A rotor (2) according to the preceding claim, comprising two salient poles.

3. The rotor (2) according to one of the preceding claims, a salient pole comprising a first pair of slots (9), two slots of the first pair of slots (9) being laterally delimited by the lug (11) and the pole shoe (17) of the corresponding salient pole.

4. The rotor (2) according to the preceding claim, one salient pole comprising a second pair of slots (10), the two slots of the second pair of slots being laterally delimited by the lug (11) and the interpolar region (E) or another lug (11) of the corresponding salient pole.

5. The rotor (2) according to any one of the preceding claims, the slots of the first pair of slots (9) having a smaller depth than the slots of the second pair of slots (10).

6. The rotor (2) according to the preceding claim, wherein the width e of the lug (11) is proportional to the effective height (H pu ) is between 0.1 and 0.

15.

7. The rotor (2) according to any one of the preceding claims, wherein the ratio between the width of the salient poles aligned with the second pair of slots (10) and the width of the salient poles aligned with the first pair of slots (9) is between 1 and 1.

15.

8. The rotor (2) according to any one of the preceding claims, wherein the width L of the salient pole aligned with a pair of slots is cp,i , in particular the width L of the salient pole aligned with the first pair of grooves (9) cp,1 , and the pole width L p The ratio between them is between 0.5 and 0.

55.

9. A rotor (2) according to any one of the preceding claims, at least one wedge (13) closing at least one slot over at least a portion of its length.

10. Rotor (2) according to the preceding claim, the slot being closed by a plurality of wedges (13) distributed over the length of the slot along the axis of rotation X of the rotor.

11. Rotor (2) according to one of the two preceding claims, one or more wedges (13) directly closing the slot over a portion of its length that is strictly less than 100% of its length.

12. The rotor (2) according to one of the two preceding claims, wherein the width of at least one wedge (13) or all wedges (13) is less than 50% of the length of the slot, better less than 40% of the length of the slot, or less than 30% of the length of the slot, or even less than 20% of the length of the slot.

13. A rotor (2) according to any one of the preceding claims, comprising cooling channels (14) extending parallel to the axis of rotation of the rotor.

14. A rotating electrical machine (1) comprising a rotor (2) according to any one of the preceding claims, in particular with an air cooling circuit.

15. The electric machine (1) according to the preceding claim, the ratio between the diameter of the rotor (2) and the outer diameter of the electric machine (1) being between 0.58 and 0.63.

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