Stator coil type coil for high-voltage shielding motor, manufacturing method, stator and motor

Abstract

The invention discloses a stator coil type coil for a high-voltage shielding motor, a manufacturing method, a stator and a motor, the coil type coil comprises a continuous coil body made of a conductive material, the coil body comprises two parallel long straight line segments, bevel edge segments connected with the two ends of the straight line segments, and nose parts located at the joints of the bevel edge segments; the turn-to-turn insulating layer and the ground insulating layer are coated outside the conductive material; the coil body forms an integrated full-mould-pressing structure through mould pressing forming, the mould pressing forming range covers all the straight line sections and the bevel edge sections connecting the straight line sections and the nose part, and the nose part is not covered by a mould. The problems of difficulty in coil inserting of high-voltage and small-size stators, poor insulation reliability, low motor efficiency and the like are solved.

Description

Technical Field

[0001] This invention relates to the field of motor product technology, specifically to stator coils for high-voltage shielded motors, manufacturing methods, stators, and motors. Background Technology

[0002] High-voltage (6kV and above) shielded motors are core equipment in energy, mechanical drive and other fields. However, their stator coils are limited by the compact space structure of shielded motors, the high insulation reliability requirements and the difficulty of manufacturing processes, making large-scale application difficult.

[0003] Existing technologies, such as the semi-circular molded winding scheme for multi-pole motors, suffer from problems such as large motor size and low efficiency; the strip-type wire bar scheme has the drawbacks of large welding workload on the inclined section and high risk of insulation damage; while the scheme of reducing the difficulty of winding by increasing the inner circle of the stator will lead to increased motor size, weight and rotor friction loss, resulting in poor economic efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a stator coil for a high-voltage shielded motor, a manufacturing method, a stator, and a motor, in order to solve at least one related technical problem in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, this application provides a stator coil for a high-voltage shielded motor, comprising: A continuous coil body made of conductive material, the coil body comprising two parallel long straight segments, a hypotenuse connecting the two ends of the straight segments, and a nose located at the junction of the hypotenuse segments; Inter-turn insulation layer and ground insulation layer covering the conductive material; The coil body is formed into an integral fully molded structure by molding. The molding range covers all the straight segments and the beveled segments connecting the straight segments and the nose, while the nose is not covered by the mold.

[0006] This solution is suitable for shielded motors with high voltage, 2 poles or higher speeds. Compared with the traditional half-circle molded stator winding solution for multi-pole motors, it can significantly reduce the size and weight of the motor at the same power, making the stator structure more compact. Compared with half-circle molded coils, fully molded coils significantly improve the insulation structure and reliability of the coils during the assembly of segmented stators.

[0007] To address the issues of large size and low efficiency in multi-pole motor designs, in one optional embodiment, the coil is applied to a 2-pole shielded motor, and the pitch between the two straight segments is 2 / 3τ or 5 / 6τ, where τ is the pole pitch; the span is from slot 1 to... slot or Slot, Z1 is the number of stator slots.

[0008] To visually define and guarantee the "large pitch" characteristic of the coil, in one optional embodiment, the central angle (α+β) corresponding to the span between the two straight line segments is 100° to 170°. This large angle is a direct geometrical manifestation of the aforementioned large pitch, ensuring that the coil can wrap around a larger stator area, which is a key geometric guarantee for achieving a high winding coefficient and thus reducing stator size.

[0009] To address the problem of corona discharge caused by concentrated electric field in the inclined section of a high-voltage motor, leading to insulation aging, in one optional embodiment, the ground insulation layer includes a mica tape wrapping layer; the coil is also provided with an anti-corona structure, which includes a low-resistance anti-corona layer located at both ends of the straight section and extending to the inclined section, and a high-resistance anti-corona layer located on the inclined section and overlapping with the low-resistance anti-corona layer.

[0010] To eliminate the electric field concentration effect caused by sharp corners, the connection between the straight segment and the inclined segment is set as a rounded corner R transition. In an optional embodiment, the straight segment and the inclined segment are connected by a rounded corner R transition. Several layers of mica tape are wrapped around the rounded corner R part of the straight segment's groove opening as reinforced insulation; and / or anti-corona tape and a half-overlapping protective tape for the inclined segment are wrapped around the inclined segment and the nose.

[0011] Secondly, embodiments of this application also provide a method for manufacturing the stator coil, comprising the steps of: A conductive material is provided to wind a continuous coil body having two long straight segments, a beveled segment, and a nose. An inter-turn insulation layer is wrapped around the coil body; Wrap the ground insulation layer and install an anti-corona structure; Full molding process: The coil with completed insulation wrapping is placed in a mold, and the insulating material covering the straight and inclined sections is molded and cured by heating and pressurizing; The insulating material in the nasal region is heat-baked and cured. Insulation performance tests were performed on the cured coil.

[0012] To address the challenges of complex nose shapes, high difficulty and cost in manufacturing molds that cover the nose, in one alternative embodiment, the mold cavity used in the full molding step covers the straight and inclined segments of the coil, but avoids the nose.

[0013] Thirdly, embodiments of this application also provide a shielded motor stator, including a stator core, wherein a plurality of stator coils are embedded in slots of the stator core.

[0014] By applying the coil described in this invention to the stator assembly, the stator achieves advantages such as compact structure, reliable insulation, and high efficiency. It is particularly suitable for small-diameter segmented stator structures, significantly reducing the volume and weight of the stator core.

[0015] Specifically, multiple coils are embedded in the stator core slots according to a certain pattern and connected by their inclined sections to form a complete winding. The precise molding dimensions and high mechanical strength of the coils ensure the feasibility and safety of assembly in a confined space.

[0016] Fourthly, embodiments of this application also provide a shielded motor, including the shielded motor stator.

[0017] The final shielded motor, thanks to the adoption of the aforementioned advanced stator coils and stator structure, achieves overall miniaturization, lightweighting, high efficiency, and high operational reliability, making it particularly suitable for applications with stringent space and performance requirements, such as high-voltage shielded electric pumps in nuclear power plants and ship propulsion.

[0018] The beneficial effects that the stator coil, manufacturing method, stator, and motor disclosed in this application may bring include, but are not limited to: 1. Achieved miniaturization and weight reduction of high-voltage shielded motors: Compared with traditional multi-pole motor solutions, the two-pole maximum span design of this invention improves the winding coefficient, allowing the use of a smaller stator core and a shorter coil slant section at the same power, thereby significantly reducing the overall size and weight of the motor.

[0019] It can also significantly reduce the outer diameter of the rotor, reduce the frictional loss generated by the rotor rotating in the medium (water), and greatly improve the efficiency of the shielded motor.

[0020] 2. Improved insulation reliability and motor lifespan: The fully molded structure creates a dense, gapless rigid insulator, enabling it to withstand the harsh assembly stresses in a small-diameter segmented stator and eliminating insulation damage caused by winding. The complete anti-corona structure and locally reinforced insulation ensure that the coil operates at high voltages of 6kV and above without the risk of corona corrosion, greatly extending the motor's service life and operational reliability.

[0021] 3. Simplified manufacturing process and improved production quality and efficiency: Using a complete coil design, no welding or subsequent insulation wrapping is required on the beveled section after stator winding, completely eliminating quality risks such as incomplete soldering and heat damage caused by welding. This is particularly suitable for coils with a high number of turns (≥20 turns), resulting in a significant leap in production efficiency and consistency. The full molding process ensures high consistency in size and angle across batches of products through high-precision molds, facilitating automated production and making stator assembly smoother and faster. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the coil of the present invention.

[0023] Figure 2 This is a cross-sectional view of the straight segment of the coil.

[0024] Figure 3 This is a schematic diagram of the coil insulation anti-corona structure.

[0025] Figure 4 This is a schematic diagram of the coil arrangement in the stator of a 2-pole motor.

[0026] Figure 5 This is a schematic diagram of a coil molding die.

[0027] Illustration: 1-Long straight section, 2-Beveled section, 3-Nose, 4-Leader wire, 5-Low resistance anti-corona layer, 6-High resistance anti-corona layer, 7-Beveled section protective strip, 8-Mold cavity, 9-Straight section mold, 10-Beveled section mold. Detailed Implementation

[0028] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0030] like Figure 1 As shown, in a first aspect, this application provides a stator coil for a high-voltage shielded motor, comprising: A continuous coil body made of conductive material, the coil body comprising two parallel long straight segments, a beveled segment connecting the two ends of the straight segments, and a nose located at the connection of the beveled segments; wherein, one end of the nose is provided with a lead wire for connecting to an input power source; Inter-turn insulation layer and ground insulation layer covering the conductive material; The coil body is formed into an integral fully molded structure by molding. The molding range covers all the straight segments and the beveled segments connecting the straight segments and the nose, while the nose is not covered by the mold.

[0031] The cross section of the straight segment is as follows Figure 2 As shown, because the voltage of shielded motors reaches 6kV and above, and the inner diameter of the stator core is relatively small (generally not exceeding Ф250mm), the number of coil turns is relatively large, reaching 20 turns or more. Copper wire is used for the electromagnetic wire, and inter-turn insulation is wrapped between each turn of electromagnetic wire. After the coil is wrapped with inter-turn insulation and the straight section is cured, and before the main insulation is wrapped, an inter-turn insulation withstand voltage test is required.

[0032] The straight section of the coil in this application is embedded in the stator core slot, forming the effective part of the electromagnetic induction; the beveled section and the nose are located outside the stator core, forming the circuit connection and mechanical support. The straight section and the beveled section are integrally hot-pressed by a mold, that is, full molding, so that the insulating material in this area, such as polyacrylic mica tape, melts, flows and solidifies under high temperature and high pressure, forming a dense, strong and dimensionally precise integral insulating shell.

[0033] To achieve smooth assembly of high-voltage coils within the confined inner circle of a segmented stator while ensuring undamaged insulation, this application employs a fully molded structure for the straight and inclined sections of the coil. This technical solution offers at least three advantages: First, it significantly improves the mechanical stiffness and strength of the straight sections and slotted areas of the coil, enabling them to withstand the extrusion and friction forces during assembly. Second, it eliminates air gaps and micropores within the insulation layer, substantially enhancing the electrical strength and corona resistance of the insulation. Third, the mold ensures the precision of key coil dimensions and angles, guaranteeing consistency in mass production and ease of assembly.

[0034] To address the issues of large size and low efficiency in multi-pole motor designs, in one optional embodiment, the coil is applied to a 2-pole shielded motor, and the pitch between the two straight segments is 2 / 3τ or 5 / 6τ, where τ is the pole pitch; the span is from slot 1 to... slot or Slot, Z1 is the number of stator slots.

[0035] The inventors of this application discovered through research that by selecting a large pitch as defined by the above-mentioned technical solution, the winding coefficient of the fundamental wave can be significantly improved, thereby reducing the number of coil turns or stator size while generating the same magnetomotive force, ultimately achieving miniaturization, weight reduction and improved efficiency of the motor.

[0036] It should be noted that the pitch can also be selected from other large pitch values ​​close to 2 / 3τ or 5 / 6τ, such as 0.7τ, but 2 / 3τ and 5 / 6τ are the optimal choices for overall performance (winding factor, harmonic suppression).

[0037] like Figure 4As shown, in order to intuitively define and guarantee the "large pitch" characteristic of the coil, in one optional embodiment, the central angle (α+β) corresponding to the span between the two straight line segments is 100° to 170°. This large angle is a direct geometrical manifestation of the aforementioned large pitch, which ensures that the coil can wrap around a larger stator area and is a key geometric guarantee for achieving a high winding coefficient and thus reducing the stator size.

[0038] It should be noted that the lower and upper limits of the angle range can be fine-tuned according to the specific motor design, for example, from 105° to 165°, but 100°-170° covers the needs of most high-efficiency, large-span designs.

[0039] like Figure 3 As shown, in order to solve the problem that the electric field concentration in the inclined section of a high-voltage motor easily generates corona, leading to insulation aging, in an optional embodiment, the ground insulation layer includes a mica tape wrapping layer; the coil is also provided with an anti-corona structure, which includes a low-resistance anti-corona layer disposed at both ends of the straight section and extending to the inclined section, and a high-resistance anti-corona layer disposed in the inclined section and overlapping with the low-resistance anti-corona layer.

[0040] An anti-corona structure, consisting of overlapping low-resistance and high-resistance layers, is incorporated into the coil surface. This structure ensures a uniform potential distribution on the coil surface, controls surface leakage current within a safe range, prevents corona discharge, and guarantees long-term reliable motor operation.

[0041] Specifically, the low-resistivity anti-corona layer mainly covers the high electric field intensity area at the slot opening to smooth out the electric field concentration at the slot opening. The high-resistivity anti-corona layer covers the sloping side area with lower electric field intensity and overlaps with the low-resistivity layer to form a continuous shielding layer with varying resistance gradient, thereby effectively suppressing and eliminating surface corona discharge.

[0042] The anti-scintillation layer material can be silicon carbide or conductive paint, and the wrapping method can be coating or wrapping. The overlapping method can be overlapping or stepped overlapping.

[0043] To eliminate the electric field concentration effect caused by sharp corners, the connection between the straight segment and the inclined segment is set as a rounded corner R transition. In an optional embodiment, the straight segment and the inclined segment are connected by a rounded corner R transition. Several layers of mica tape are wrapped around the rounded corner R part of the straight segment's groove opening as reinforced insulation; and / or anti-corona tape and a half-overlapping protective tape for the inclined segment are wrapped around the inclined segment and the nose.

[0044] The rounded corner R is the curved transition area connecting the straight segment and the beveled segment. Reinforced insulation is located in this R-corner area, which is where the electric field is most concentrated and the mechanical stress is greatest. The beveled segment protective strip covers the beveled segment and the anti-corona layer at the nose.

[0045] Specifically, to further strengthen the insulation of this weak point, reinforced insulation is added to the rounded corner R section, forming a locally thickened insulation protective layer. Furthermore, to protect the anti-corona layer on the beveled section from environmental humidity, pollution, and mechanical damage, anti-corona tape and semi-overlapping protective tape are wrapped around the beveled section and the nose area. The semi-overlapping ensures tight, gapless coverage.

[0046] It should be noted that the radius (R) can be adjusted according to the voltage level and spatial constraints. The number of reinforcing insulation layers can be determined based on the electric field simulation results. The protective strip material can be a high-temperature resistant and corrosion-resistant polyimide film or similar material.

[0047] To meet the high-turns requirement of shielded motors with small stator inner diameters under high voltage levels, in one optional embodiment, the rated operating voltage of the coil is 6kV or higher, and the number of turns of a single coil is greater than or equal to 20 turns. The fully molded structure and weldless coil design of this invention are precisely designed to overcome the core pain points of poor insulation reliability and high welding process risks of traditional solutions in this high-voltage, high-turns scenario.

[0048] It should be noted that the voltage level can be specifically 6kV, 10kV, etc. The number of turns can be determined according to the electromagnetic design of the motor, such as 22 turns, 25 turns, etc., and there is no specific limitation on this.

[0049] Secondly, embodiments of this application also provide a method for manufacturing the stator coil, comprising the steps of: A conductive material is provided to wind a continuous coil body having two long straight segments, a beveled segment, and a nose. An inter-turn insulation layer is wrapped around the coil body; Wrap the ground insulation layer and install an anti-corona structure; Full molding process: The coil with completed insulation wrapping is placed in a mold, and the insulating material covering the straight and inclined sections is molded and cured by heating and pressurizing; The insulating material in the nasal region is heat-baked and cured. Insulation performance tests were performed on the cured coil.

[0050] The above method enables the manufacture of coils with both high insulation performance and precise mechanical dimensions, employing a step-by-step curing process of "full molding + post-curing of the nose". This method ensures the density of insulation and dimensional accuracy in key coil components through molding; furthermore, it avoids the difficulties of manufacturing the nose mold, achieving curing through heat baking, thus reducing process complexity and cost while maintaining quality.

[0051] Specifically, the full molding process applies heat and pressure to the straight and beveled sections using a mold, causing the multi-adhesive insulating material to cross-link and cure. Due to its complex shape, the nose section undergoes a separate thermal baking process for curing.

[0052] The temperature, pressure, and time parameters for molding can be adjusted according to the insulation material specifications. Hot baking can be performed using an oven or induction heating.

[0053] like Figure 5 As shown, to address the issues of complex nose shape, high difficulty and cost in manufacturing molds covering the nose, in one optional embodiment, the mold used in the full molding step includes a mold cavity, a straight segment mold, and a beveled segment mold. The mold cavity covers the straight segment and beveled segment of the coil, but avoids the nose. The straight segment mold is used to mold the straight segment of the coil, and the beveled segment mold is used to mold the beveled segment of the coil.

[0054] This is an optimized design that balances insulation performance and manufacturing cost. While ensuring the insulation quality of the core area, straight sections and beveled edges, it significantly reduces the complexity of the mold and processing costs.

[0055] To comprehensively inspect and ensure the insulation reliability of high-voltage coils, multiple rigorous electrical testing procedures are implemented after manufacturing. In one optional embodiment, the insulation performance tests include at least one of the following: inter-turn insulation impulse test, power frequency AC withstand voltage test, and corona test. These tests can respectively evaluate the strength of inter-turn insulation, the withstand voltage capability of main insulation, and the effectiveness of the anti-corona structure, ensuring that every coil leaving the factory meets the requirements for high-voltage operation.

[0056] Thirdly, embodiments of this application also provide a shielded motor stator, including a stator core, wherein a plurality of stator coils are embedded in slots of the stator core.

[0057] By applying the coil described in this invention to the stator assembly, the stator achieves advantages such as compact structure, reliable insulation, and high efficiency. It is particularly suitable for small-diameter segmented stator structures, significantly reducing the volume and weight of the stator core.

[0058] Specifically, multiple coils are embedded in the stator core slots according to a certain pattern and connected by their inclined sections to form a complete winding. The precise molding dimensions and high mechanical strength of the coils ensure the feasibility and safety of assembly in a confined space.

[0059] Fourthly, embodiments of this application also provide a shielded motor, including the shielded motor stator.

[0060] The final shielded motor, thanks to the adoption of the aforementioned advanced stator coils and stator structure, achieves overall miniaturization, lightweighting, high efficiency, and high operational reliability, making it particularly suitable for applications with stringent space and performance requirements, such as high-voltage shielded electric pumps in nuclear power plants and ship propulsion.

[0061] The core of this invention lies in providing a large-span, fully molded stator coil specifically designed for high-voltage, small-size shielded motors. Its working principle is a collaborative process, which can be broken down as follows: Electromagnetic energy conversion principle: When a high-voltage current is passed through the coil, a strong alternating magnetic field is generated in its two parallel long straight segments.

[0062] The magnetic field interacts with the motor rotor, following the law of electromagnetic induction, thereby generating electromagnetic torque, driving the rotor to rotate, and realizing the conversion of electrical energy into mechanical energy. This is the basic working principle of all motor coils.

[0063] The principle behind the efficiency improvement of "large span": This invention is specifically applied to 2-pole motors and employs a large pitch of 2 / 3τ or 5 / 6τ (τ being the pole pitch). The winding pitch directly affects its winding coefficient.

[0064] By selecting such a large pitch, the coil span angle (α+β) can reach 100° to 170°, which can more effectively cut the magnetic field and significantly improve the winding coefficient of the fundamental wave. This means that, under the premise of generating the same magnetomotive force and torque, the ampere-turns of the coil can be reduced or a smaller stator core can be used, thus directly laying the theoretical foundation for the miniaturization and high efficiency of motors.

[0065] The principle behind "full molding" ensuring reliability: Structural Forming and Reinforcement: High temperature and pressure are applied to the straight and beveled sections of the coil (up to near the nose) using a specially designed mold. This process melts, flows, and completely solidifies the insulating material, such as the wrapped multi-adhesive mica tape, forming a dimensionally precise, fixed-shape, and internally dense rigid insulator. This provides the necessary mechanical strength for assembling the coil in confined spaces.

[0066] Insulation performance optimization: The molding process extrudes air and volatiles from the insulating material, eliminating internal air gaps and micropores. This is crucial for high-voltage insulation, as air gaps are a major cause of partial discharge (corona discharge) and insulation breakdown. Full molding thus significantly improves the dielectric strength and corona resistance life of the coil.

[0067] Special treatment for the nose: Due to the complex shape of the nose, it is not covered by the mold, but is cured by subsequent overall heat baking. This "step-by-step curing" process cleverly avoids the high cost and process difficulties caused by complex mold manufacturing while ensuring the integrity of insulation.

[0068] High-voltage insulation and anti-corona principle: Main insulation: The ground insulation layer formed by the mica tape provides the basic insulation strength required between the coil conductors and the stator core (ground potential).

[0069] Anti-corona structure: A low-resistance anti-corona layer (covering the high electric field inlet and nearby straight sections) and a high-resistance anti-corona layer (covering the lower electric field sloping sections) are connected by resistors on the coil surface to form a smooth potential distribution gradient. This structure can effectively suppress and leak surface current, prevent the electric field from concentrating locally, and thus completely eliminate surface corona discharge.

[0070] Local reinforcement: In the transition area of ​​the rounded corner R at the outlet where the electric field is most concentrated, multiple layers of mica tape are added as reinforcement insulation to provide key protection for this weak point of both electric field and mechanical stress.

[0071] The following specific embodiment will be used to illustrate this application in detail: Example: A stator coil for a 6kV / 500kW shielded motor This embodiment provides a stator coil for a 6kV high-voltage, 2-pole shielded motor. The inner diameter of the stator core of this motor is Ф248mm, and the number of stator slots Z1 is 36.

[0072] 1. Coil structure and materials Coil body: Utilizing oxygen-free copper flat wire with a cross-sectional area of ​​4mm × 8mm as the conductive material, it is wound into the following shape using a winding machine. Figure 1 The diagram shows a continuous coil structure. Each coil has 22 turns.

[0073] Inter-turn insulation: A layer of polyimide film-mica composite tape is wrapped between each turn of copper wire as inter-turn insulation.

[0074] Insulation to ground: SMC-734 type low-adhesion mica tape is used, which is continuously wrapped on the coil body in a semi-overlapping manner to ensure that the double-sided insulation thickness to ground reaches 3.0mm, which meets the insulation specification requirements of 6kV voltage level.

[0075] 2. Key Design Parameters Pitch and span: This embodiment uses a large pitch of 5 / 6τ. According to the formula K=5 / 6×Z1 / 2+1, the number of slots spanned is K=5 / 6×36 / 2+1=16 slots. That is, one straight segment of the coil is embedded in slot 1, and the other straight segment is embedded in slot 16.

[0076] Central angle: such as Figure 4 As shown, the central angle (α+β) between the two straight line segments corresponding to this span is measured to be 142°, which falls within the preferred range of 100°-170°.

[0077] 3. Implementation of Insulation and Anti-Corona Structure like Figure 3 As shown, the anti-sickness structure is implemented according to the following steps: Low-resistance anti-corona layer: At the slot outlet of the two straight segments of the coil, and within a range of about 100mm extending towards the inclined side, a low-resistance semiconductor glass ribbon is half-overlapped and wrapped.

[0078] High-resistance anti-corona layer: A silicon carbide-based high-resistance anti-corona tape is half-overlapped around the entire slanted section of the coil. This high-resistance anti-corona layer overlaps with the low-resistance anti-corona layer of the straight section by 20mm, forming a smooth resistance transition.

[0079] Enhanced insulation: In the rounded corner R transition area at the coil slot exit (R corner radius designed to be 5mm), two additional layers of SMC-734 mica tape are wrapped as reinforced insulation, with the wrapping length extending 150mm outward from the slot to ensure coverage and beyond the cut-off end of the low-resistance anti-corona layer.

[0080] Bevel section protection: Finally, a layer of PTFE-impregnated fiberglass protective tape is half-wrapped around the entire bevel section and nose of the coil to protect the anti-corona layer from environmental erosion and mechanical damage.

[0081] 4. Full molding manufacturing process The method for manufacturing a coil includes the following steps: Winding and initial curing: After winding the coil and completing the inter-turn insulation wrapping, the straight section is subjected to medium-frequency induction heating for initial shaping and curing.

[0082] Insulation and anti-corona wrapping: Wrap the ground insulation layer and anti-corona structure according to the above scheme.

[0083] Full molding: The coil is placed in... Figure 5 The special mold shown has a cavity that precisely covers the entire straight segment of the coil and the beveled segments at both ends, but completely avoids the two noses.

[0084] Molding parameters: heating temperature: 170℃±5℃; unit pressure: 15MPa; heat holding and pressure holding time: 90 minutes.

[0085] During this process, the epoxy resin in the multi-adhesive mica tape melts and flows, filling all gaps, and is cured under pressure to form a dense and robust overall insulation structure.

[0086] Nose curing: After molding, the entire coil is transferred into an oven and baked at 155°C for 8 hours to fully cure the insulation material of the nose that was not molded.

[0087] Insulation performance testing: A complete set of factory tests were performed on the cured coil. Inter-turn insulation impulse test: The 0.5μF capacitor impulse method was used, the peak test voltage was 3.5kV, and the waveforms were consistent.

[0088] AC withstand voltage test: Apply 24kV (2 times the rated voltage + 4kV) AC voltage for 1 minute, with no breakdown or flashover.

[0089] Corona test: In a dark room, a power frequency voltage of 6.6kV (1.1 times the rated voltage) was applied and detected with a photomultiplier tube. No corona emission phenomenon was observed.

[0090] 5. Assembly of stator and motor Twenty-four coils, manufactured as described above, are embedded into the segmented stator core slots according to the design. Because the straight and beveled sections of the coils are fully molded, they possess extremely high dimensional accuracy and mechanical strength, ensuring no damage to the insulation layer during assembly within the narrow inner circle of the stator. After all coils are embedded and connected, no welding of the beveled sections or additional insulation treatment is required, thus forming a complete shielded motor stator. Finally, this stator is assembled with the rotor, shielding sleeve, and other components to form a complete high-voltage shielded motor.

[0091] This invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes and modifications within the scope of the appended claims. For example, other highly conductive metals can be used as conductive materials; the type of insulating material and the number of wrapping layers can be adjusted according to different voltage levels; the temperature and pressure parameters for molding and curing can be optimized according to the specifications of the insulation system used.

[0092] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A stator coil for a high-voltage shielded motor, characterized in that, include: A continuous coil body made of conductive material, the coil body comprising two parallel long straight segments, a hypotenuse connecting the two ends of the straight segments, and a nose located at the junction of the hypotenuse segments; Inter-turn insulation layer and ground insulation layer covering the conductive material; The coil body is formed into an integral fully molded structure by molding. The molding range covers all the straight segments and the beveled segments connecting the straight segments and the nose, while the nose is not covered by the mold.

2. The stator coil according to claim 1, characterized in that, The coil is used in a 2-pole shielded motor, and the pitch between the two straight segments is 2 / 3τ or 5 / 6τ, where τ is the pole pitch; the span is from slot 1 to... slot or Slot, Z1 is the number of stator slots.

3. The stator coil according to claim 2, characterized in that, The central angle (α+β) corresponding to the span between the two line segments is between 100° and 170°.

4. The stator coil according to claim 1, characterized in that, The ground insulation layer includes a mica tape wrapping layer; the coil is also provided with an anti-corona structure, which includes a low-resistance anti-corona layer located at both ends of the straight segment and extending to the inclined segment, and a high-resistance anti-corona layer located on the inclined segment and overlapping with the low-resistance anti-corona layer.

5. The stator coil according to claim 4, characterized in that, The straight segment and the inclined segment are transitioned by a rounded corner R. At the rounded corner R part of the groove opening of the straight segment, several layers of mica tape are wrapped as reinforcement insulation; and / or the inclined segment and the nose are wrapped with anti-halo tape and half-overlapping protective tape for the inclined segment.

6. A method for manufacturing a stator coil as described in any one of claims 1 to 5, characterized in that, Including the following steps: A conductive material is provided to wind a continuous coil body having two long straight segments, a beveled segment, and a nose. An inter-turn insulation layer is wrapped around the coil body; Wrap the ground insulation layer and install an anti-corona structure; Full molding process: The coil with completed insulation wrapping is placed in a mold, and the insulating material covering the straight and inclined sections is molded and cured by heating and pressurizing; The insulating material in the nasal region is heat-baked and cured. Insulation performance tests were performed on the cured coil.

7. The method according to claim 6, characterized in that, In the full molding step, the mold cavity used covers the straight and beveled sections of the coil, but avoids the nose.

8. The method according to claim 6, characterized in that, The insulation performance tests include inter-turn insulation impulse test, power frequency AC withstand voltage test and corona test.

9. A shielded motor stator, comprising a stator core, characterized in that, The stator core is provided with a plurality of stator coils as described in any one of claims 1 to 5 embedded in its slots.

10. A shielded electric motor, characterized in that, Includes the shielded motor stator as described in claim 9.

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