Manufacturing methods and structures for electromagnetic coils

Abstract

An electromagnetic coil (200) includes a compact multi-turn coil (210b) with at least one conductor (211) coated with a first insulation material (212). The conductor has a plurality of turns (213), compacted to bring neighbouring turns into physical contact. The first insulation material (212) has a first melting temperature. The main function of the first insulation material (212) is to have a turn-to-turn insulation. The coil also includes a coil liner (220) made of a second insulation material with a second melting temperature lower than or equal to the first melting temperature. The coil liner (220) provides electrical insulation between the compact multi-turn coil (210b) and a core of an electromagnetic device. This integrated insulation ensures reliable operation when the electromagnetic coil (200) is positioned over the core of the electromagnetic device.

Description

[0001] Manufacturing Methods and Structures for Electromagnetic Coils

[0002] Field of the invention

[0003] The invention relates to the field of electromagnetic devices and their manufacturing process. More specifically it relates to an electromagnetic coil, and to a method for manufacturing an electromagnetic coil, and to electromagnetic devices using such an electromagnetic coil.

[0004] Background of the invention

[0005] In electromagnetic devices such as motors, generators, transformers, and actuators, windings play a fundamental role in converting electrical energy into magnetic fields. The performance, safety, and longevity of these devices heavily depend on effective insulation of the windings. Proper insulation ensures electrical isolation, prevents leakage currents, and maintains structural integrity under various mechanical and thermal stresses.

[0006] Magnet wire insulation involves coating individual wire windings, typically with enamel or thermoplastic materials, to prevent electrical leakage and short circuits between adjacent turns. However, these coatings can degrade over time, especially under mechanical stress at bending points.

[0007] Slot liner insulation isolates the high-voltage windings from the stator, typically using materials like paper or polymers. While effective in preventing electrical contact between windings and the stator core, traditional slot liners often have poor thermal conductivity and create air voids that impede efficient heat dissipation.

[0008] Slot wedge insulation, on the other hand, uses non-conductive wedges inserted into stator slots to stabilize the windings and prevent movement caused by mechanical forces during operation. These components, however, add complexity to the assembly process and can affect performance in high-stress environments.

[0009] Filler insulation involves thermally conductive fillers to eliminate air voids between the slot liner and the coil, thereby improving heat transfer between the windings and the stator. It also prevents friction between adjacent conductors and mitigates wear on electrical insulation. While this improves thermal management, it complicates maintenance since impregnated windings are difficult to remove or repair.

[0010] Despite these measures, certain technical challenges persist, such as premature insulation failure due to mechanical tension at bending points, poor heat dissipation caused by air voids, and structural instability stemming from inadequate stabilization of the windings (e.g. the need for non-conductive wedges to prevent conductors from moving outside of the stator slots due to high mechanical forces indicates an issue with structural integrity in the design, particularly under operational stress). Additionally, traditional manufacturing and maintenance processes can be time-consuming and costly, particularly in high-performance devices where these issues are magnified.

[0011] Innovations addressing these challenges are essential to improve the reliability, efficiency, and ease of maintenance in modern electromagnetic devices.

[0012] Summary of the invention

[0013] It is an object of embodiments of the present invention to provide a good electromagnetic coil and an electromagnetic device which comprises such an electromagnetic coil and to provide a good method for manufacturing an electromagnetic coil and a method for manufacturing an electromagnetic device which comprises such an electromagnetic coil.

[0014] The above objective is accomplished by a method and device according to the present invention.

[0015] In a first aspect embodiments of the present invention relate to a method for manufacturing an electromagnetic coil.

[0016] The method comprises providing a multi-turn coil comprising at least one conductor, having a plurality of turns wherein neighboring turns are spaced apart from each other, substantially shaped in the form of the eventual electromagnetic coil, wherein the at least one conductor is insulated with a first insulation material, the first insulation material having a first melting temperature.

[0017] The method, furthermore, comprises compacting the multi-turn coil thereby bringing neighbouring turns in physical contact with each other, thus obtaining a compact multi-turn coil.

[0018] The method, furthermore, comprises applying a coil liner over the compact multi-turn coil wherein the coil liner extends over the plurality of turns, the coil liner comprising a second insulation material with a second melting temperature lower than or equal to the first melting temperature, wherein the coil liner is applied to provide insulation between the compact multiturn coil and a core of an electromagnetic device. In embodiments of the present invention the coil liner is positioned such that, when the electromagnetic coil is positioned over the core of the electromagnetic device, the coil liner provides insulation between the compact multi-turn coil and a core of an electromagnetic device.

[0019] It is an advantage of embodiments of the present invention that the need for a traditional slot liner is eliminated while ensuring insulation between the core and the electromagnetic coil when the electromagnetic coil is mounted on the core. It is an advantage of embodiments of the present invention that thermal stability, and structural integrity of the electromagnetic coil are provided by applying the coil liner.

[0020] Where in embodiments of the present invention reference is made to compacting the multi-turn coil, reference is made to the action of bringing neighbouring turns of the multi-turn coil in physical contact with each other thereby reducing or even completely eliminating air gaps between the neighbouring turns.

[0021] Where in embodiments of the present invention reference is made to the core of an electromagnetic device, reference is made to the component that serves to concentrate and guide magnetic flux generated by the current flowing through a surrounding electromagnetic coil. This is applicable to various electromagnetic devices such as for example motors, transformers, actuators, etc.

[0022] In embodiments of the present invention the electromagnetic coil is provided by obtaining at least one bare conductor substantially shaped in the form of the eventual electromagnetic coil wherein neighboring turns are spaced apart from each other, and subsequently applying the first insulation material to the at least one bare conductor. In embodiments of the present invention the neighboring turns of the provided electromagnetic coil are spaced apart from each other in their natural state (i.e. without having to apply a force to the provided electromagnetic coil).

[0023] It is an advantage of embodiments of the present invention that when insulation is applied to the at least one conductor after it has been shaped into its final form, the insulation layer is not subjected to the bending, twisting, or compressive forces that occur during coil formation. This prevents cracks, weak points, and other defects in the insulation, leading to a more reliable and durable insulation layer. It is, moreover, advantageous that the neighboring turns are spaced apart from each other as this allows to apply the first insulation material around the complete conductor, without having to separate the neighboring turns by pulling the turns away from each other. By insulating the bare conductor(s) once it is in its final shape, the first insulation material can be applied more uniformly, especially around bends and corners without any mechanical tension, ensuring consistent insulation thickness throughout the coil. This enhances the electrical insulation between turns and reduces the risk of partial discharge or insulation breakdown.

[0024] In embodiments of the present invention the first insulation material may be applied on the at least one conductor through spraying, dipping, electrochemical processing of metals, or other appropriate techniques.

[0025] In embodiments of the present invention the method comprises inserting one or more spacers each between adjacent turns before compacting the multi-turn coil, and removing the spacer(s) after applying the coil liner. In case of multiple spacers each spacer may be provided between a different combination of subsequent turns.

[0026] It is an advantage of embodiments of the present invention that by inserting the spacers the creation of additional functional spaces, such as a cooling channel, within the electromagnetic coil is enabled.

[0027] The use of a removable spacer ensures that the compacting and coil liner application steps create a stable, consolidated multi-turn coil without unintended air gaps or weak points. When the spacer is removed, the cooling channel remains as an integrated feature of the coil structure, adding functionality without disrupting the coil's structural integrity.

[0028] By inserting and then removing a spacer during the manufacturing process, a dedicated space or channel is created within the coil liner. This channel can be utilized as a cooling pathway to actively remove heat from within the coil. This cooling channel allows for direct fluid cooling (such as oil or air), which can effectively dissipate heat, improving the overall thermal management of the electromagnetic device.

[0029] In embodiments of the present invention the provided at least one conductor is a flat conductor. In alternative embodiments of the present invention also conductors with a different cross-section (e.g. round, ellipsoidal) can be used.

[0030] It is an advantage of embodiments of the present invention that air voids between turns can be more effectively reduced or even eliminated when the conductor is a flat conductor in comparison to a conductor with a circular cross-section. It should be noted that also conductors with a circular cross-section fall within the scope of the present invention. In both cases, compacting the multi-turn coil reduces the air voids, however, the air voids are more efficiently reduced or even eliminated in case of a conductor with a flat cross-section. In embodiments of the present invention the coil liner is applied by coating one or more layers of insulation material.

[0031] It is an advantage of embodiments of the present invention that the thickness of the integrated coil liner can be precisely controlled ensuring tight tolerances that leave no air voids between the windings and the core.

[0032] In embodiments of the present invention the multi-turn coil is obtained by 3D-printing of the turns of the at least one conductor.

[0033] In embodiments of the present invention the multi-turn coil is obtained by tooling of the at least one conductor.

[0034] In embodiments of the present invention the coil liner is applied through spraying, dipping, powder coating, or other appropriate techniques.

[0035] In embodiments of the present invention an electromagnetic device is manufactured by using a method in accordance with embodiments of the present invention for manufacturing an electromagnetic coil, and by inserting the electromagnetic coil over a core of the electromagnetic device.

[0036] In a second aspect embodiments of the present invention relate to an electromagnetic coil comprising:

[0037] - a compact multi-turn coil comprising at least one conductor coated with a first insulation material wherein the at least one conductor has a plurality of turns wherein a multi-turn coil is compact when neighbouring turns are in physical contact with each other, and wherein the insulation material has a first melting temperature,

[0038] - a coil liner comprising a second insulation material with a second melting temperature lower than or equal to the first melting temperature, wherein the coil liner is applied to provide insulation between the compact multi-turn coil and a core of an electromagnetic device.

[0039] Where in embodiments of the present invention reference is made to neighbouring turns, reference is made to turns which are next to each other. Neighbouring turns do not have a functional element, such as a cooling channel, between them.

[0040] In embodiments of the present invention the electromagnetic coil comprises one or more spaces, each provided between two subsequent turns.

[0041] Such a space may for example serve as cooling channel to remove heat from the electromagnetic coil.

[0042] In embodiments of the present invention the at least one conductor is a flat conductor. In embodiments of the present invention the thickness of the coating with the first insulation material is between 10 pm and 200 pm.

[0043] In embodiments of the present invention the thickness of the coil liner is between 50 pm and 800 pm.

[0044] Embodiments of the present invention also relate to an electromagnetic device comprising at least one core for concentrating and guiding electromagnetic flux, and at least one electromagnetic coil according to embodiments of the present invention wherein the at least one electromagnetic coil is surrounding the at least one core. For each electromagnetic coil, the coil liner provides insulation between the compact multi-turn coil and the core which it surrounds.

[0045] Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.

[0046] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0047] Brief description of the drawings

[0048] FIG. 1 shows schematic drawings of an electromagnetic coil in accordance with embodiments of the present invention and of intermediate products obtained when using a method in accordance with embodiments of the present invention.

[0049] FIG. 2 shows schematic drawings of an electromagnetic coil comprising a functional space in accordance with embodiments of the present invention and of intermediate products obtained when using a method in accordance with embodiments of the present invention.

[0050] FIG. 3 shows schematic drawings of a multi-strand coil comprising a functional space in accordance with embodiments of the present invention and of intermediate products obtained when using a method in accordance with embodiments of the present invention.

[0051] FIG. 4 shows schematic drawings of a multi-strand coil comprising a functional space in accordance with embodiments of the present invention and of intermediate products obtained when using a method in accordance with embodiments of the present invention comprising an optional step for double layer windings.

[0052] FIG. 5 shows pictures of a intermediate products and of a resulting electromagnetic coil, when manufacturing a coil in accordance with embodiments of the present invention. FIG. 6 shows a picture of a compacted multi-turn coil, in accordance with embodiments of the present invention.

[0053] FIG. 7 shows schematic drawings of a stator obtained using a method in accordance with embodiments of the present invention.

[0054] FIG. 8 shows schematic drawings of a stator, having a hairpin configuration with distributed winding, obtained using a method in accordance with embodiments of the present invention.

[0055] Any reference signs in the claims shall not be construed as limiting the scope.

[0056] In the different drawings, the same reference signs refer to the same or analogous elements.

[0057] Detailed description of illustrative embodiments

[0058] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

[0059] The terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0060] It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

[0061] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0062] Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

[0063] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0064] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0065] Where in embodiments of the present invention reference is made to a conductor that is 'substantially shaped' in the form of the eventual electromagnetic coil, reference is made to a conductor that has been formed into a configuration that closely resembles the final operational geometry of the electromagnetic coil. This includes shaping the conductor into its intended arrangement of turns, bends, and dimensions, ensuring that compatibility with the core or housing of the electromagnetic device is maintained after the application of subsequent processing steps, such as compacting or applying insulation layers. The term 'substantially shaped' allows for minor adjustments or refinements that may occur during these processing steps without altering the essential structure or functionality of the coil.

[0066] In a first aspect embodiments of the present invention relate to a method (100) for manufacturing an electromagnetic coil (200). The method comprises providing (110) a multiturn coil (210a). The multi-turn coil includes at least one conductor (211) having a plurality of turns (213). The conductor is substantially shaped in the form of the eventual electromagnetic coil (200). Neighboring turns of the provided multi-turn coil (210a) are spaced apart from each other. The at least one conductor (211) is insulated with a first insulation material (212). The first insulation material has a specified first melting temperature.

[0067] The method further comprises compacting (120) the multi-turn coil (210a). Compacting brings neighbouring turns into physical contact with each other. This results in a compact multiturn coil (210b).

[0068] The method also includes applying (130) a coil liner (220) over the compact multi-turn coil (210b) wherein the coil liner (220) extends over the plurality of turns (213). The coil liner (220) is composed of a second insulation material. The second insulation material has a second melting temperature lower than or equal to the first melting temperature. The coil liner (220) is applied to provide insulation between the compact multi-turn coil (210b) and the core of an electromagnetic device. This ensures proper insulation when the electromagnetic coil is positioned over the core of the electromagnetic device. In embodiments of the present invention the coil liner (220) provides insulation between the compact multi-turn coil (210b) and another part of the electromagnetic device.

[0069] In a second aspect embodiments of the present invention relate to an electromagnetic coil (200). The coil comprises a compact multi-turn coil (210b). The compact multi-turn coil includes at least one conductor (211) coated with a first insulation material (212). The at least one conductor (211) has a plurality of turns (213). The multi-turn coil (210b) is considered compact when neighbouring turns (213) are in physical contact with each other. The first insulation material (212) has a specified first melting temperature.

[0070] The electromagnetic coil (200) further includes a coil liner (220) which extends over the plurality of turns (213). The coil liner (220) comprises a second insulation material. The second insulation material has a second melting temperature that is lower than or equal to the first melting temperature. The coil liner (220) is applied to provide insulation between the compact multi-turn coil (210b) and a core (291) of an electromagnetic device (290). This ensures proper insulation when the electromagnetic coil (200) is positioned over the core of the electromagnetic device (290).

[0071] FIGS. 1 to 4 illustrate sequences of steps applied in methods in accordance with embodiments of the present invention.

[0072] These figures demonstrate the progression of the method, starting with the provision (110) of a multi-turn coil (210a) substantially shaped in the form of the eventual electromagnetic coil (200). FIGS. 1 to 4 further illustrate the compacting step (120), where neighbouring turns (213) are brought into physical contact to form a compact multi-turn coil (210b), as well as the application of a coil liner (220) to provide insulation between the compact multi-turn coil (210b) and a core of an electromagnetic device (290). These figures provide a schematic drawings of the intermediate products and configurations resulting from each step of the method, including the multi-turn coil (210a), compact multi-turn coil (210b), and final electromagnetic coil (200).

[0073] The conductor (211) comprises one or more conducting materials such as for example copper or aluminum.

[0074] In embodiments of the present invention the at least one conductor (211) is initially shaped substantially in the form of the eventual electromagnetic coil (200). In that case the at least one conductor (211) is obtained (111) without any first insulation material (212) applied. Various manufacturing techniques, including 3D printing or traditional tooling, can be employed to shape the at least one conductor (211). This ensures that the multi-turn coil (210a) is in its intended operational configuration before the first insulation material (212) is applied, avoiding strain or damage to the insulation during subsequent processing steps.

[0075] Obtaining (111) a bare pre-shaped conductor is, however, not strictly required. In embodiments of the present invention the multi-turn coil (210a) may be obtained by substantially shaping a conductor coated with a first insulation material in the form of the eventual electromagnetic coil (200).

[0076] In embodiments of the present invention the first insulation material (212) is applied to the at least one bare conductor.

[0077] In embodiments of the present invention the thickness of the coating with the first insulation material is between 10 pm and 200 pm.

[0078] In embodiments of the present invention the conductor (211) can be pre-heated above the melting point of the insulation material, and the coating can be applied through spraying, dipping, or other appropriate techniques, followed by curing. In embodiments of the present invention this layer with the first insulation material

[0079] (212) is critical for preventing electrical shorts between turns while allowing for efficient heat dissipation due to its relatively thin profile.

[0080] The step of compacting (120) involves applying a force (e.g. a mechanical force or a pressure) to the multi-turn coil (210a) to bring its neighbouring turns (213) into direct physical contact with each other. This process reduces or eliminates air gaps between adjacent turns, resulting in a structurally stable and thermally efficient compact multi-turn coil (210b). By minimizing these voids, the compacting step enhances the coil's ability to dissipate heat generated during operation and improves the overall mechanical integrity of the coil. By minimizing these voids he process reduces or removes the need for resin impregnation, enhancing thermal performance.

[0081] Compacting can be achieved using various techniques, such as mechanical clamping, or vacuum-assisted compression. Mechanical clamping devices or thermal tapes or thermoplastic loop locks or form-fitting moulds may hold the turns in place. The thermoplastic loop locks provide a heat-resistant, flexible solution for maintaining consistent pressure on the turns, ensuring a tight and uniform configuration. Vacuum-assisted compression can for example be used to remove any trapped air (e.g. especially in case of round conductors), leading to a more compact and uniform coil.

[0082] An example of a compact multi-turn coil (210b) of which the turns (213) are held in place by thermoplastic loop locks (301) is shown in FIG. 6.

[0083] The goal of compacting is to create a dense, cohesive coil structure where the turns are tightly packed, ensuring uniform contact and optimal alignment. This compacting step also prepares the coil for the subsequent application of the coil liner (220), ensuring a smooth and effective insulation layer that adheres uniformly to the compact multi-turn coil (210b).

[0084] In embodiments of the present invention the coil liner (220), comprising a second insulation material, is applied (130) over the outer circumference of the compact multi-turn coil (210b), as illustrated in FIGS. 1 to 4. A picture of an exemplary electromagnetic coil (200) comprising a coil liner (220) is shown in the right picture of FIG. 5. The primary function of the coil liner (220) is to provide insulation between the compact multi-turn coil (210b) and the core (291) of the electromagnetic device (290). This replaces traditional paper slot liners, ensuring effective electrical isolation. The coil liner may also provide insulation between the compact multi-turn coil (210b) and another part of the electromagnetic device (290). In embodiments of the present invention the coil liner keeps the multi-turn coil compact (e.g. keeps the neighboring turns in contact with each other), even after removing mechanical clamping devices such as loop locks. The coil liner (220) which extends over the plurality of turns (213) provides mechanical stability to the compact multi-turn loop.

[0085] In embodiments of the present invention the second melting temperature of the coil liner (220) is lower than or equal to the first melting temperature of the first insulation material (212). By ensuring that the second melting temperature is lower than or equal to the first melting temperature, the application of the coil liner (220) can be performed at a temperature that does not exceed the thermal tolerance of the first insulation material (212) without damaging or compromising the first insulation material (212) that coats the conductor (211).

[0086] In embodiments of the present invention the first insulation material (212) and the second insulation material used in the coil liner (220) can be composed of the same material. This ensures compatibility between the layers, resulting in improved bonding and uniform adhesion.

[0087] A method in accordance with embodiments of the present invention may be used for manufacturing an electromagnetic device (290) by first manufacturing an electromagnetic coil and by thereafter inserting the electromagnetic coil over a core (291) of the electromagnetic device (290).

[0088] An electromagnetic device (290), in accordance with embodiments of the present invention comprises at least one core (291) for concentrating and guiding electromagnetic flux, and at least one electromagnetic coil (200), in accordance with embodiments of the present invention, wherein the at least one electromagnetic coil (200) is surrounding the at least one core (291). For each electromagnetic coil (200) the coil liner (220) provides insulation between the compact multi-turn coil (210b) and the core (291) which it surrounds. This is applicable to various electromagnetic devices such as for example motors, generators, transformers, actuators, etc.

[0089] In embodiments of the present invention the coil liner (220) is applied only along the active length of the compact multi-turn coil (210b) to provide insulation between the compact multi-turn coil (210b) and the core (291) when the electromagnetic coil (200) is mounted over the core.

[0090] In embodiments of the present invention the coil liner where the envisioned electromagnetic device is a motor or a generator, the coil liner may for example only be necessary in the active length of the coil inside the stator slot and not on the end windings unless they come into contact with the stator core (291). To ensure the elimination of air voids, compression of the compact multi-turn coil (210b) is required during the application process. This step minimizes gaps between the turns (213), ensuring a consistent and void-free insulation layer.

[0091] In embodiments of the present invention the thickness of the coil liner (220) ranges from 50 pm to 800 pm and can be achieved through a single application or multiple coating steps, depending on the required final thickness.

[0092] Various techniques, including mechanical clamping devices, thermal tapes, thermoplastic loop locks or form-fitting moulds, may be used to hold the compact multi-turn coil (210b) securely during the coating process to maintain its compact configuration.

[0093] The coil liner (220) is also designed to ensure tight mechanical tolerances between the compact multi-turn coil (210b) and the core (e.g. stator core) (291). This precise control of the insulation thickness eliminates the need for additional measures such as slot impregnation or non-conductive wedges. By achieving strong mechanical contact between the winding body and the core (291), the coil liner (220) enhances both the structural integrity and electrical insulation of the electromagnetic coil (200).

[0094] In embodiments of the present invention the method (100) comprises inserting (141) one or more spacers (241), such as a steel bar or other blocking element, each between two adjacent turns before compacting (120) the multi-turn coil (210a). Thus an electromagnetic coil is obtained wherein which comprises one or more spaces (242), each provided between two subsequent turns (213). The method (100) further comprises removing (142) the spacer (241) after applying (130) the coil liner. Examples thereof are illustrated in FIG. 2, FIG. 3 and FIG. 4.

[0095] The spaces (242) may for example serve as cooling channels at specific locations within the compact multi-turn coil (210b) to address hotspots, such as those near the slot opening, which are prone to losses during high-frequency operation. During the application of the coil liner (220), the spacer (241) creates a space for the cooling channel. After the coil liner (220) has been applied, the spacer (241) is removed, leaving behind the cooling channel (242). A split spacer design (e.g. split steel bar) can be utilized to facilitate easy removal after the coating process, reducing the risk of adhesion issues with the insulation material. Additionally, using non-stick coatings on the spacer (241) could further simplify removal. Another approach involves 3D-printed spacers at early design stage to account for the cooling channel, eliminating the need for complex post-process spacer removal. The application of the coil liner (220) can be performed using methods such as spraying, dipping, or powder coating, depending on the manufacturing environment and the desired thickness of the insulation layers.

[0096] The thickness of the first insulation material (212) and the coil liner (220) can be adjusted based on the operational requirements of the electromagnetic device (290). For higher voltage applications, thicker insulation layers may be applied, while thinner coatings can be used for low-power machines to prioritize thermal management. This flexibility allows for precise control of the insulation layers, ensuring optimal performance and compatibility with the electromagnetic coil's (200) intended application.

[0097] In embodiments of the present invention the conductor (211) used in the multi-turn coil (210a) is specifically designed with a flat cross-sectional shape, as opposed to a round or other geometry. This flat configuration offers several advantages in the manufacturing process and performance of the electromagnetic coil (200). It is noted that in other embodiments of the present invention the cross-section of the coil may be round or have another geometry.

[0098] The flat conductor (211) allows for closer packing of neighbouring turns (213) when compacted (120), significantly reducing or eliminating air voids between adjacent turns. This enhanced packing improves thermal conductivity, as there are fewer gaps to impede heat transfer from the turns to the surrounding coil liner (220) or the core (291).

[0099] Additionally, the flat shape provides a larger surface area for the first insulation material (212) to adhere to, resulting in a more uniform and consistent insulation layer. This reduces the likelihood of weak points in the insulation, which can occur with round conductors at curves or bends.

[0100] Using a flat conductor also enhances structural stability during and after the compacting step (120), as the flat surfaces of adjacent turns create a more mechanically robust configuration. This is particularly beneficial in high-performance applications where the coil is subjected to significant mechanical stresses.

[0101] The geometry of the turns (213) in the multi-turn coil (210a) can vary depending on the specific requirements of the application and the dimensions of the core (291) of the electromagnetic device (290). They may for example be round, square, rectangular or have another shape.

[0102] FIG. 1 provides a step-by-step illustration of the manufacturing process for an electromagnetic coil (200). The left 3D drawing depicts a multi-turn coil comprising a conductor (211) with turns (213). Step (110) includes step (111), showing a cross-section of the bare conductor with turns (213), and step (112), showing a cross-section of the multi-turn coil (210a) with a plurality of turns (213) coated with the first insulation material (212). Step (120) illustrates a cross-section after compacting the multi-turn coil (210a), resulting in the compact multi-turn coil (210b). Step (130) shows a cross-section after the application of the coil liner (220), forming the final electromagnetic coil (200).

[0103] FIG. 2 illustrates a variation of the manufacturing process for an electromagnetic coil (200), similar to FIG. 1, but incorporating the use of a spacer (241). Step (110) includes step (111), showing a cross-section of the bare conductor with turns (213), and step (112), showing a cross-section of the multi-turn coil (210a) with a plurality of turns (213) coated with the first insulation material (212).

[0104] In this variation, step (141) introduces a spacer (241) between two adjacent turns of the multi-turn coil (210a) before compacting (120). Step (120) illustrates a cross-section after compacting the multi-turn coil (210a), with the spacer (241) maintaining a designated space. Step (130) shows the application of the coil liner (220) to the compact multi-turn coil (210b). Step (142) depicts the removal of the spacer (241) after the coil liner (220) is applied, resulting in the final electromagnetic coil (200) with an integrated space (242) for cooling channels or other functionalities. A sealed space (142) is obtained after the spacer (241) is removed.

[0105] FIG. 3 illustrates the manufacturing process for an electromagnetic coil (200) using multi-strand coils, expanding on the process shown in FIG. 2. Each cross-section shows two columns wherein each column represents the turns (213) of a single strand within the multiturn coil (210a).

[0106] Step (111) shows a cross-section of a bare conductor with turns (213) for each strand. Step (112) illustrates the multi-turn coil (210a) with each strand coated with the first insulation material (212).

[0107] In step (141), a spacer (241) is inserted between the turns, extending across the strands to create a designated space.

[0108] Step (120) shows the compacted multi-turn coil (210b), where neighbouring turns within a strand are in physical contact while the spacer (241) maintains a designated space. Step (130) depicts the application of the coil liner (220), encapsulating the compact multi-turn coil (210b). Finally, step (142) shows the removal of the spacer (241), resulting in the electromagnetic coil (200) with integrated spaces extending between the strands for cooling channels or other functionalities. FIG. 4 illustrates a variation of the manufacturing process for an electromagnetic coil (200) as shown in FIG. 1, but with an optional step for creating double-layer windings. The process begins similarly with step (110), including step (111), showing a cross-section of the bare conductor (211) with turns (113), and step (112), showing the multi-turn coil (210a) with a plurality of turns (213) coated with the first insulation material (212).

[0109] In step (141), a spacer (241) is inserted between adjacent turns of the multi-turn coil (210a). A compact multi-turn coil (210b) is obtained compacting (120). After compacting (120), an additional step (143) is performed, wherein a removable cover (143), such as a thermoplastic tape, is applied to one side of the multi-turn coil. This cover (243) protects one side of the plurality of turns during subsequent steps.

[0110] Step (130) is performed to apply the coil liner (220) over the compact multi-turn coil (210b). After applying the coil liner (220), the removable cover (243) is taken off (144), also removing the coil liner from the covered side of the compact multi-turn coil. The spacer (241) may be removed (142) before or after removing the removable cover (243).

[0111] This sequence can be repeated to produce two compact multi-turn coils (210b), each with a coil liner (220) applied on all sides except the side where the cover (143) was removed. In step (145), these two compact multi-turn coils (210b) are arranged with their open sides positioned against each other, resulting in double-layer windings for enhanced performance or application-specific configurations.

[0112] FIG. 5 presents four images showcasing multi-turn coils manufactured using a method in accordance with embodiments of the present invention.

[0113] From left to right the following pictures are shown. The left picture depicts a multi-turn coil comprising a conductor (211) with a plurality of turns (213). The turns shown in this image have a rectangular cross-section, with dimensions suitable for the application. The width of the conductor may for example range between 1 mm and 50 mm the thickness of the conductor may for example range between 0.4mm and 5mm.

[0114] The second picture displays the multi-turn coil after the at least one conductor (211) has been insulated with a first insulation material, covering each turn (213) to ensure turn-to- turn electrical isolation.

[0115] The third picture shows the compact multi-turn coil (210b), which has been covered with a thermoplastic tape (301). The tape completely covers the end windings to protect specific areas during subsequent processing steps. The fourth picture illustrates the final electromagnetic coil (200) after the coil liner (220) has been applied to the compact multi-turn coil (210b). The thermoplastic tape has been removed. The coil liner is applied to provide insulation between the coil and a core of an electromagnetic device.

[0116] FIG. 6 shows a picture of a compact multi-turn coil (210b), illustrating the use of thermoplastic loop locks positioned at the outer ends of the turns (213). These loop locks securely hold the turns (213) together, maintaining their compact configuration and ensuring the turns (213) remain in physical contact. This approach provides structural stability during subsequent processing steps, such as the application of the coil liner (220), and minimizes air gaps between the turns to enhance thermal and mechanical performance.

[0117] FIG. 7 provides schematic drawings of an electromagnetic device (290) comprising a plurality of cores (291) with electromagnetic coils (200) mounted over these cores (291) wherein the plurality of cores (291) are mounted in an outer ring (292). A coil liner (220) is applied to each electromagnetic coil (200) to provide insulation between the core (291) and the electromagnetic coil (200) positioned around the core (291). In this example, the electromagnetic device (290) is a motor. The method (100) described relies on the electromagnetic coil (200) being manufactured in its final shape prior to mounting, which necessitates the use of stator cores (291) with open slots, as closed slots with pole shoes would prevent proper insertion of the coil.

[0118] To address this design constraint, particularly for motors that traditionally use closed slots, a segmented stator core design can be employed. In such a configuration, the stator core (291) is split into segments, allowing the electromagnetic coil (200) to be inserted after the coil liner (220) has been applied to the compact multi-turn coil (210b). This approach eliminates the need for open slots and provides greater flexibility in the design and assembly of the electromagnetic device (290).

[0119] The segmented stator core design can also be extended to other electromagnetic devices, such as transformers, enabling the integration of pre-manufactured electromagnetic coils (200) into the core (291) after completing the insulation process. This ensures compatibility with the final shape of the coil while enhancing the versatility of the manufacturing process.

[0120] FIG. 8 provides schematic drawings of a segmented stator comprising a plurality of cores (291). The cores (291) can be inserted in the openings of the electromagnetic coil (200) in the hairpin (HP) section of the coil (200). The whole of the plurality of cores (291) and the electromagnetic coil (200) is mounted in the outer ring (292) of the stator. The top right drawings show a cross-section of the compact multi-turn coil (210b). It shows two turns (213) with a first insulation material (212) is provided on the conductor. In the right drawing, the coil liner (220) is applied to the compact multi-turn coil (210b), resulting in the formation of the electromagnetic coil (200).

[0121] It is an advantage of embodiments of the present invention that the process modularity makes it easier to replace or maintain individual coils in the event of failure, reducing downtime.

[0122] As discussed before, the at least one bare conductor substantially shaped in the form of the eventual electromagnetic coil may be obtained by 3D printing or tooling. 3D printing is well-suited for manufacturing electromagnetic coils (200) with fine geometries, particularly for machines with power ratings below 600 kW. For larger coils, manual forming of the at least one conductor (211) into its final shape before the application of the first insulation material (212) can be employed as an alternative. Additionally, modular coil construction may be used to facilitate scalability. In this approach, smaller sections of the multi-turn coil (210a) are fabricated individually and then assembled, for example, by welding, before proceeding to the compacting step (120) and the application of the coil liner (220). This modular method allows for efficient production of large-scale electromagnetic coils (200) while maintaining precision in geometry and ensuring high-quality insulation layers.

Claims

Claims1.- A method (100) for manufacturing an electromagnetic coil (200) comprising:- providing (110) a multi-turn coil (210a) comprising at least one conductor (211), having a plurality of turns (213) wherein neighboring turns are spaced apart from each other, substantially shaped in the form of the eventual electromagnetic coil (200), wherein the at least one conductor (211) is insulated with a first insulation material (212), the first insulation material having a first melting temperature,- compacting (120) the multi-turn coil (210a) thereby bringing neighbouring turns in physical contact with each other, thus obtaining a compact multi-turn coil (210b),- characterized in that the method comprises applying (130) a coil liner (220) over the compact multi-turn coil (210b) wherein the coil liner (220) extends over the plurality of turns (213), the coil liner (220) comprising a second insulation material with a second melting temperature lower than or equal to the first melting temperature, wherein the coil liner (220) is applied by coating one or more layers of insulation material over the compact multi-turn coil to provide insulation between the compact multi-turn coil (210b) and a core of an electromagnetic device.2.- The method (100) according to claim 1, wherein the electromagnetic coil is provided (120) by:- obtaining (111) at least one bare conductor substantially shaped in the form of the eventual electromagnetic coil, and- subsequently applying (112) the first insulation material to the at least one bare conductor.3.- The method (100) according to any of the previous claims, the method (100) comprising:- inserting (141) one or more spacers (241) each between two adjacent turns before compacting (120) the multi-turn coil (210a),- removing (142) the spacer (241) after applying (130) the coil liner.4.- The method (100) according to any of the previous claims, wherein the provided (110) at least one conductor (211) is a flat conductor.5.- A method (100) according to any of the previous claims, wherein the multi-turn coil (210a) is obtained by 3D-printing of the turns (211) of the at least one conductor (211).6.- A method (100) according to any of the claims 1 to 4, wherein the multi-turn coil (210a) is obtained by tooling of the at least one conductor.7.- A method (100) according to any of the claims 1 to 4, wherein the coil liner (220) is applied (130) through spraying, dipping, or powder coating.8.- A method for manufacturing an electromagnetic device (290), the method comprising:- using a method (100) in accordance with any of the previous claims manufacturing an electromagnetic coil (200),- inserting the electromagnetic coil (200) over a core (291) of the electromagnetic device (290).9.- An electromagnetic coil (200) comprising:- a compact multi-turn coil (210b) comprising at least one conductor (211) coated with a first insulation material (212) wherein the at least one conductor (210) has a plurality of turns (213) wherein a multi-turn coil (210b) is compact when neighbouring turns are in physical contact with each other, and wherein the insulation material (212) has a first melting temperature,- characterized in that the electromagnetic coil comprises a coil liner (220) coated with one or more layers of a second insulation material over the compact multi-turn coil, wherein the second insulation material has a second melting temperature lower than or equal to the first melting temperature, wherein the coil liner (220) is applied to provide insulation between the compact multi-turn coil (210b) and a core (291) of an electromagnetic device (290) and wherein the coil liner (220) extends over the plurality of turns (213).10.- An electromagnetic coil (200) according to claim 9 wherein the electromagnetic coil (200) comprises one or more spaces (242), each provided between two subsequent turns (213).11.- An electromagnetic coil (200) according to any of the claims 9 or 10 wherein the at least one conductor (211) is a flat conductor.12.- An electromagnetic coil (200) according to any of the claims 9 to 11 wherein the thickness of the coating with the first insulation material is between 10 pm and 200 pm.13.- An electromagnetic coil (200) according to any of the claims 9 to 12 wherein the thickness of the coil liner (220) is between 50 pm and 800 pm.14.- An electromagnetic device (290) comprising at least one core (291) for concentrating and guiding electromagnetic flux, and at least one electromagnetic coil (200) according to any of the claims 9 to 13 wherein the at least one electromagnetic coil (200) is surrounding the at least one core (291) and wherein for each electromagnetic coil (200) the coil liner (220) provides insulation between the compact multi-turn coil (210b) and the core (291) which it surrounds.

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