A high-temperature and high-voltage resistant circular composite insulated electromagnetic wire and its preparation method

Abstract

This invention discloses a high-temperature and high-voltage resistant circular composite insulated electromagnetic wire and its preparation method. It is a high-temperature and high-voltage resistant composite insulated electromagnetic wire suitable for 3000-meter deep-sea oil pumping motors. The electromagnetic wire, from the inside out, consists of: a copper conductor, a corona-resistant polyimide (PI) inner layer, an ultra-thin glass fiber layer, and an outer layer. This invention, through insulation material design and argon / oxygen plasma interface activation of the glass fiber layer, extrusion of the outer layer, and a four-stage gradient cooling process, forms an insulation layer with a reinforced structure, completely solving the problems of delamination at 250℃, partial discharge at high voltage, damage from reciprocating threading of long stators, and cracking during potting in existing products. The product of this invention shows no delamination or cracking after 1000 hours of continuous aging in an oil immersion environment at 250℃ and 30MPa, and no partial discharge at 3300V, meeting the long-term reliable operation requirements of deep-sea oil pumping motors.

Description

Technical Field

[0001] This invention belongs to the field of special electromagnetic wire technology, specifically relating to a high-temperature and high-voltage resistant circular composite insulated electromagnetic wire and its preparation method. Background Technology

[0002] Electromagnetic wire is a type of wire used in motors and electrical appliance windings. It generates a magnetic field through current or induces current by cutting magnetic lines of force, thus converting electrical energy into magnetic energy. It is also known as winding wire. The process of potting the stator windings of a motor with epoxy resin or other potting compounds, which cures to form a sealed whole, is part of the motor encapsulation process. Preventing cracking during potting is a critical requirement. With deep-sea oil and gas development entering the 3000-meter ultra-deep water range, submersible motor stators have reached lengths of 10 meters, facing multiple extreme operating conditions including 250℃ high temperature, 30MPa high pressure, long-term oil immersion, potting curing stress, long-distance reciprocating winding, and 3300V high voltage. As a core component of electrical products such as motors, the performance of electromagnetic wire directly affects the safety and reliability of the entire electrical system. The insulation layer of the electromagnetic wire, as a crucial part protecting the conductor, preventing current leakage, and ensuring the normal transmission of electromagnetic effects, is particularly important in its formulation design and manufacturing process. The applicant previously coated a flat wire with a first polyimide layer, a second polyimide layer, and a polyetheretherketone resin layer. The first polyimide layer was formed by coating a polyimide varnish with a viscosity of 12–18 Pa·s at 30°C, and the second polyimide layer was formed by coating a polyimide varnish with a viscosity of 5–10 Pa·s at 30°C. This provided an electromagnetic wire for new energy vehicle drive motors with resistance to high-frequency pulse partial discharge and ultra-high voltage breakdown performance. However, its high-temperature resistance was poor and it did not meet the requirements for high-temperature and high-pressure applications at 250°C. Existing technology incorporates a polyetheretherketone fiber layer between the conductive copper core and the polyimide layer, and a lubricating layer on the outer surface of the polyimide insulation layer, significantly improving the insulation performance of the electromagnetic wire. However, its operating temperature is around 90°C, making it difficult to adapt to applications above 200°C. Existing technologies produce special electromagnetic wires through steps such as laying, oil immersion, preheating, high-temperature extrusion, cooling, and winding. However, these wires exhibit poor resistance to continuous aging under 250℃ and 30MPa oil immersion conditions. Another existing method involves precision rolling of oxygen-free copper rods into rectangular cross-sections. A corona-resistant polyimide film is then formed on the copper conductor's surface, encasing it. A polyetheretherketone resin layer is then coated onto the corona-resistant polyimide film, followed by cooling and drying before winding. However, this method also suffers from poor resistance to high temperatures and pressures. In summary, existing electromagnetic wires, including those suitable for high-temperature applications, are mostly enameled copper round wires with an insulation layer surrounding the enameled wire. For wound wires, current products struggle to meet the 250℃ and 30MPa oil immersion test, limiting their application in submersible motors operating in ultra-deep waters up to 3000 meters. Summary of the Invention

[0003] For the application of submersible motors, existing technologies have significant shortcomings: delamination under long-term high temperature of 250℃, inability to meet the 250℃, 30MPa oil immersion test requirements, and immediate partial discharge under 3300V high voltage, leading to rapid insulation breakdown; neither commercially available products nor publicly available electromagnetic wires have been reported to simultaneously meet the comprehensive reliability requirements of 250℃ high temperature, 30MPa high voltage, 3300V withstand voltage, reciprocating threading, and long-term vibration. This invention, through the design of each layer of materials combined with inorganic reinforcement, plasma interface treatment, high-temperature extrusion, and gradient cooling preparation processes, systematically solves the technical problems of delamination at 250℃ / 30MPa, 3300V partial discharge, threading damage, potting cracking, and high-voltage breakdown from four dimensions: structure, materials, interface, and process. The composite insulated electromagnetic wire disclosed in this invention undergoes continuous aging for 1000 hours at 250℃ and 30MPa oil immersion, with the insulation layer showing no cracking, delamination, or detachment; it exhibits no partial discharge at a rated voltage of 3300V and a breakdown voltage ≥10kV; after 10 reciprocating passes through the stator slot, the insulation layer shows no damage, pinholes, or delamination, and the adhesive does not crack during potting.

[0004] The present invention adopts the following technical solution.

[0005] A high-temperature and high-voltage resistant circular composite insulated electromagnetic wire includes a conductor and an insulating layer that encloses the conductor. The insulating layer comprises, from the inside out, a polyimide film layer, a glass fiber tape layer, and an outer layer. The outer layer is a glass fiber reinforced polyetheretherketone layer or an aromatic polyester liquid crystal polymer layer. The glass fiber tape layer contains polyimide hot melt adhesive and has undergone plasma activation treatment.

[0006] The high-temperature and high-voltage resistant circular composite insulated electromagnetic wire of this invention has the physical properties of not delaminating after oil immersion treatment at 250℃ and 30MPa and without partial discharge after 3300V withstand voltage treatment.

[0007] In this invention, the thickness of the polyimide film layer is 0.1–0.15 mm, and it is wrapped in both directions with a 50%–53% overlap rate; the thickness of the glass fiber tape layer is 0.05–0.08 mm, and the wrapping overlap rate is 40%–50%; the thickness of the outer layer is 0.2–0.25 mm.

[0008] This invention discloses a method for preparing the above-mentioned high-temperature and high-voltage resistant circular composite insulated electromagnetic wire, comprising the following steps: (1) Wrap a polyimide film around the outer wall of the conductor; (2) Then wrap the glass fiber tape around it and sinter it; (3) Then, plasma activation treatment is used, and the outer layer is extruded to obtain a high temperature and high pressure resistant round composite insulated electromagnetic wire.

[0009] In this invention, in step (1), a polyimide film is wrapped around the outer wall of the conductor using a bidirectional reverse wrapping method with a wrapping rate of 50% to 53%.

[0010] In this invention, in step (2), the glass fiber tape is wrapped with a wrapping overlap rate of 40-50%, and then sintered in nitrogen at 280-350°C to form a polyimide film layer and a glass fiber tape layer.

[0011] In this invention, in step (3), argon / oxygen low-temperature plasma activation treatment is used, and then the outer layer is extruded to obtain a high-temperature and high-voltage resistant round composite insulated electromagnetic wire; the power of plasma activation treatment is 80-120W and the time is 15-25s.

[0012] In this invention, in step (3), the outer layer is extruded and then cooled to obtain a high-temperature and high-voltage resistant circular composite insulated electromagnetic wire. Preferably, a stepped cooling process is used; for example, 2 to 5 steps of cooling are used.

[0013] This invention discloses an insulating layer for high-temperature and high-voltage resistant circular composite insulated electromagnetic wire. The insulating layer comprises, from the inside out, a polyimide film layer, a glass fiber tape layer, and an outer layer. The outer layer is a glass fiber reinforced polyether ether ketone layer or an aromatic polyester liquid crystal polymer layer. The glass fiber tape layer contains polyimide hot melt adhesive and has undergone plasma activation treatment.

[0014] This invention discloses a motor stator, which includes the above-mentioned high-temperature and high-voltage resistant circular composite insulated electromagnetic wire.

[0015] This invention discloses an electric motor comprising the aforementioned high-temperature and high-pressure resistant circular composite insulated electromagnetic wire.

[0016] This invention discloses the application of the above-mentioned high-temperature and high-voltage resistant circular composite insulated electromagnetic wire in the manufacture of motors.

[0017] This invention discloses the application of the above-mentioned high-temperature and high-voltage resistant circular composite insulated electromagnetic wire in the preparation of deep-sea submersible motors.

[0018] This invention discloses a novel high-temperature and high-voltage resistant circular composite insulated electromagnetic wire, the overall structure of which (from the inside to the outside) is as follows: Conductor: Φ2.5mm high-purity oxygen-free copper, round; the round copper surface is smooth, without oxide layer, scratches, burrs, oil stains and other defects, which is common knowledge; Corona-resistant PI inner layer: 0.14mm thickness, 50%–53% overlap; Ultra-thin glass fiber layer: 0.05-0.08mm thick, sintered in three stages with nitrogen, and bonded to the inner layer with PI hot melt adhesive at high temperature; Ar / O2 plasma activates the glass fiber layer, and then the outer layer is extruded to form a good interface structure. High-performance outer layer: glass fiber reinforced PEEK or aromatic polyester liquid crystal polymer (LCP), 0.22 mm thick; Total single-sided insulation thickness: approximately 0.45mm, matching 3300V rated voltage.

[0019] The outer layer material of this invention can be directly extruded, and two methods can be adopted: Option A: 30% glass fiber reinforced PEEK (GF30 / PEEK), which can be directly extruded at an extrusion temperature of 370–400℃; its coefficient of thermal expansion is approximately 15ppm / ℃, and it has good surface properties. Option B: Aromatic polyester liquid crystal polymer (LCP), a fully aromatic thermotropic liquid crystal polyester, can be directly extruded and coated, with an extrusion temperature of 310-360℃, a coefficient of thermal expansion of 1-5 ppm / ℃, a water absorption rate of <0.04%, and good surface properties.

[0020] This invention uses polyimide (PI) as the inner layer, and designs a glass fiber buffer layer plus an outer layer material, combining PI hot melt adhesive, plasma-activated interface, and gradient cooling. Specifically, the glass fiber tape is coated with PI hot melt adhesive, wrapped, and then sintered at 320-340℃, thermally fusing it with the PI inner layer. The surface of the PI / glass fiber composite layer is treated with low-temperature plasma (Ar:O2=3:1). Combined with a four-stage gradient cooling process (200℃→150℃→100℃→room temperature, cooling rate 10-20℃ / s), the insulation layer has high bonding strength and avoids internal stress. Ultimately, it achieves a non-delaminating, gapless, and partial discharge-free structure.

[0021] This invention discloses a high-temperature and high-voltage resistant circular composite insulated electromagnetic wire and its preparation method. It is a high-temperature and high-voltage resistant composite insulated electromagnetic wire suitable for 3000-meter deep-sea oil pumping motors. The electromagnetic wire, from the inside out, consists of: a copper conductor, a corona-resistant polyimide (PI) inner layer, an ultra-thin adhesive-coated glass fiber layer, and a high-performance outer layer. The high-performance outer layer is made of glass fiber reinforced PEEK or aromatic polyester liquid crystal polymer (LCP), both of which can be directly extruded and coated. The PI inner layer is 0.14 mm thick, the glass fiber reinforcement layer is 0.05–0.08 mm thick, and they are bonded using PI hot melt adhesive at high temperature. The outer layer is 0.22 mm thick, resulting in a small total insulation thickness; as is common knowledge, this thickness refers to a single-sided thickness. This invention solves the problems of 250°C high-temperature delamination and 3300V high-voltage partial discharge in existing products through glass fiber layer activation combined with argon / oxygen plasma interface, extrusion of the outer layer, and a four-stage gradient cooling process. It particularly addresses the problems of long stator reciprocating wire threading damage and potting cracking. The product of this invention showed no delamination or cracking after 1000 hours of continuous aging in an oil immersion environment at 250℃ and 30MPa, no partial discharge under a rated voltage of 3300V, a breakdown voltage ≥10kV, and an interlayer peel strength ≥15N / cm. In particular, the long stator reciprocating threading showed no damage and the glue potting showed no cracking, fully meeting the requirements for long-term reliable operation of a 3000-meter deep-sea submersible oil motor. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the cross-sectional structure of the composite insulated electromagnetic wire of the present invention; wherein, 1, conductor; 2, corona-resistant PI inner layer; 3, glass fiber reinforcement layer; 4, high-performance outer layer.

[0023] Figure 2 This is a schematic diagram of the cross-section of an existing 10-meter-long stator after glue injection. Detailed Implementation

[0024] Currently, leading international manufacturers such as Schlumberger and Baker Hughes generally use a PI / inorganic reinforcement + PEEK / LCP composite structure for their 250℃~275℃ high-temperature electromagnetic wires. However, this structure is prone to delamination at high temperatures, partial discharge caused by air gaps, and insulation cracking. In particular, submersible motors have a long and slender shape, with the ratio of the motor's outer diameter to its length reaching 1:100. This is one of the key differences between this type of motor and other motors. This objectively places higher demands on the long stator winding capability and potting performance of the electromagnetic wire. Existing products suffer from long stator reciprocating winding damage and potting cracking problems. This invention discloses a high-temperature and high-voltage resistant circular composite insulated electromagnetic wire and its preparation method. It is a composite insulated electromagnetic wire suitable for 3000-meter deep-sea submersible oil motors, 10-meter long stators, vacuum pressure potting, 250℃ / 30MPa high temperature and high voltage, and 3300V rated voltage conditions. It is high-temperature resistant, wear-resistant, oil-immersion resistant, non-delamination, non-partial discharge, and non-breakdown composite insulated electromagnetic wire. In particular, the wire does not cause damage during reciprocating threading of the long stator and does not crack during potting, fully meeting the long-term reliable operation requirements of 3000-meter deep-sea submersible oil motors.

[0025] This invention discloses a high-temperature and high-pressure resistant round composite insulated electromagnetic wire suitable for 3000-meter deep-sea oil pumping motors. It includes a conductor and an insulating layer surrounding the conductor. With the conductor as the innermost layer, the insulating layer, from the inside out, comprises: a polyimide inner layer, an ultra-thin glass fiber layer, and a high-performance outer layer. The high-performance outer layer is glass fiber reinforced polyether ether ketone (GF30 / PEEK) or aromatic polyester liquid crystal polymer (LCP), which can be directly extruded. After argon / oxygen low-temperature plasma activation treatment, the molten outer layer material is extruded to form the outer layer. The composite insulated electromagnetic wire disclosed in this invention undergoes continuous aging for 1000 hours in an oil immersion environment at 250℃ and 30MPa, without cracking, delamination, or detachment of the insulating layer. Furthermore, it exhibits no partial discharge at a rated voltage of 3300V and a breakdown voltage ≥10kV. In particular, after 10 reciprocating passes through the stator slot, the insulating layer shows no damage, pinholes, or delamination.

[0026] The raw materials used in this invention are all existing products. For example, the conductor is a Φ2.5mm high-purity oxygen-free copper conductor (one piece), with a surface roughness Ra≤0.8μm, and is conventionally polished, degreased, and dust-removed.

[0027] In this invention, the thickness of the polyimide inner layer is 0.14 mm, and it is wrapped in both directions with a 50% to 53% overlap rate.

[0028] In this invention, the thickness of the ultra-thin glass fiber layer is 0.05-0.08 mm, and a glass fiber tape with polyimide hot melt adhesive is used, with a wrapping overlap rate of 45%.

[0029] In this invention, a polyimide inner layer and a glass fiber layer are formed by sintering. Preferably, the sintering temperature is 280–350°C and the time is 10–60 s. More preferably, a three-stage stepped nitrogen sintering is adopted, which involves preheating at 290–300°C for 10–15 s, sintering at 320–340°C for 10–20 s, and sintering at 290°C for 5–15 s. After sintering at 320–340°C, the glass fiber and the polyimide inner layer are thermally fused together.

[0030] In this invention, the volume ratio of plasma activation gas is Ar∶O2=3∶1, the activation power is 80~120W, and the processing time is 15~25s.

[0031] In this invention, the high-performance outer layer is 30% glass fiber reinforced PEEK or extruded aromatic polyester LCP.

[0032] The composite insulated electromagnetic wire disclosed in this invention has an interlayer peel strength ≥15N / cm, a hot insulation resistance at 250℃ ≥5000MΩ·km, and an insulation performance retention rate ≥95% after immersion in 30MPa oil for 168 hours.

[0033] The method for preparing the high-temperature and high-voltage resistant round composite insulated electromagnetic wire suitable for 3000-meter deep-sea oil pumping motor disclosed in this invention includes the following steps performed sequentially: (1) Wrapping the outer wall of the conductor with corona-resistant polyimide film: Use CR-25 type corona-resistant polyimide self-adhesive film, wrap in both directions with a 50% to 53% overlap rate, with staggered seams and non-overlapping, and a linear speed of 5 to 15 m / min. (2) Fiberglass layer wrapping: Wrap with 0.05-0.08mm polyimide fiberglass tape, with an overlap rate of 45%; (3) Three-stage stepped sintering: Under a nitrogen protective atmosphere, the glass fiber layer and the polyimide layer are formed by three-stage stepped sintering: preheating at 300℃ for 15s, sintering at 330℃ for 15s, and sintering at 290℃ for 10s. (4) Plasma interface activation: The surface is activated by low-temperature plasma treatment using a mixed gas of argon:oxygen = 3:1 (volume ratio), with a power of 80-120W and a treatment time of 15-25s. (5) Extrusion coating: After activation, the molten outer layer material is extruded. The extrusion temperature of GF30 / PEEK is 370-400℃, and the extrusion temperature of LCP is 310-360℃. (6) Gradient cooling and shaping: The product is obtained by four-stage cooling: 200℃→150℃→100℃→room temperature, with a cooling rate of 10~20℃ / s, to eliminate internal stress.

[0034] This invention discloses a high-temperature and high-pressure resistant round composite insulated electromagnetic wire suitable for 3000-meter deep-sea oil pumping motors, the structural schematic diagram of which is shown below. Figure 1 The conductor 1 is wrapped with a corona-resistant PI inner layer 2, a glass fiber layer 3, and an outer layer 4 in sequence.

[0035] The following specific experiments illustrate the technological advancements of this invention. The raw materials used are existing products that meet the conventional requirements for electromagnetic wire. The specific preparation operations (feeding, winding, etc.) and performance testing are conventional techniques. Conductor: Φ2.5mm high-purity oxygen-free copper, polished and degreased, Ra≤0.8μm, round; CR-25 corona-resistant PI film, Wuxi Mingji; PI adhesive glass fiber tape (0.06mm), Changshu Fubang; GF30 / PEEK, Vigus; LCP, Sumitomo, Japan.

[0036] Example 1, GF30 / PEEK outer layer.

[0037] Example 2, LCP outer layer.

[0038] The preparation method of the example is as follows: (1) Wrapping the outer wall of the conductor with corona-resistant polyimide film: Use CR-25 type corona-resistant polyimide self-adhesive film, wrap in both directions with a 50% overlap rate, with staggered seams, linear speed of 10m / min, and thickness of 0.14mm. (2) Fiberglass layer wrapping: Wrap with 0.06mm polyimide fiberglass tape, with an overlap rate of 45%; (3) Three-stage stepped sintering: Under a nitrogen protective atmosphere, the polyimide layer and the glass fiber layer on its surface are formed by three-stage stepped sintering: preheating at 300℃ for 15s, sintering at 330℃ for 15s, and sintering at 290℃ for 10s. The polyimide layer is cooled to room temperature by air blowing, which is a conventional technique. (4) Plasma interface activation: The surface is activated by room temperature plasma using a mixed gas of argon:oxygen = 3:1 (volume ratio), with a power of 100W and a treatment time of 20s. The above steps are performed sequentially. (5) Extrusion coating: Molten outer layer material is extruded onto the surface of the activated wire: GF30 / PEEK extrusion temperature 390℃ (Example 1), LCP extrusion temperature 340℃ (Example 2), thickness 0.22mm; (6) Gradient cooling and shaping: The product is obtained by four-stage cooling: 200℃→150℃→100℃→room temperature, with a cooling rate of 15℃ / s, to eliminate internal stress.

[0039] Comparative Example 1 Referring to Example 1, the difference is that the plasma interface activation is omitted, and the remaining steps are the same as in Example 1.

[0040] Comparative Example 2 Referring to Example 1, the difference is that the polyimide adhesive is omitted, that is, glass fiber tape without polyimide adhesive is used, and the remaining steps are the same as in Example 1.

[0041] Comparative Example 3 Referring to Example 1, the difference is that PEEK is used instead of GF30 / PEEK as the outer layer, and the rest of the steps are the same as in Example 1.

[0042] Application Examples The existing submersible motor stator, 10 meters in length, represents the highest standard currently available for submersible motors. It employs conventional methods for reciprocating wire threading and glue application. (See attached document.) Figure 2 The small circles in the groove represent the composite insulated electromagnetic wire of this invention.

[0043] Performance testing is a standard method, briefly described below: Immersion in oil at 250℃ and 30MPa for 1000 hours: no delamination, no detachment, and no cracking are required; Tested at 3300V rated voltage after oil immersion: no partial discharge is required; Breakdown voltage after oil immersion: ≥10kV; Oil immersion peel strength: ≥15 N / cm; Insulation resistance at 250℃: ≥5000MΩ・km; 30MPa oil immersion for 168 hours: insulation performance (breakdown voltage and insulation resistance) retention rate ≥95%; Stator slot reciprocating threading 10 times: requires no damage, no pinholes, no cracks, and no delamination; After threading, apply insulating glue as usual: it should not crack.

[0044] Performance test results: Example 1: The electromagnetic wire showed no delamination, detachment, or cracking after being immersed in oil at 250℃ and 30MPa for 1000 hours; after oil immersion, it showed no partial discharge at a rated voltage of 3300V, a breakdown voltage of 15kV, and an interlayer peel strength of 18N / cm; the insulation resistance at 250℃ was 6350MΩ・km; the insulation performance retention rate was 96.8%~97.3% after 168 hours of oil immersion at 30MPa; the stator slot showed no damage, pinholes, or delamination after 10 reciprocating wire threading cycles; and no cracking occurred after conventional potting.

[0045] Example 2: The electromagnetic wire was immersed in oil at 250℃ and 30MPa for 1000h without delamination, detachment, or cracking; after immersion in oil, it showed no partial discharge at a rated voltage of 3300V and a breakdown voltage of 11kV; it was threaded through the stator slot 10 times without damage, pinholes, or delamination; and it did not crack under conventional potting.

[0046] Comparative Example 1: After immersion in oil at 250℃ and 30MPa for 1000 hours, the electromagnetic wire was partially discharged and broken down under a rated voltage of 3300V. Comparative Example 2: After immersion in oil at 250℃ and 30MPa for 1000 hours, the electromagnetic wire was partially discharged and broken down under a rated voltage of 3300V, and delamination occurred during reciprocating threading of the electromagnetic wire through the stator slot. Comparative Example 3: The electromagnetic wire cracked after conventional potting after threading.

[0047] This invention stabilizes the insulation layer by combining a glass fiber layer with argon / oxygen plasma interface activation, extruding the outer layer, and a four-stage gradient cooling process. This completely solves the problems of high-temperature delamination at 250°C and high-voltage partial discharge at 3300V in existing products, and especially solves the problems of damage from reciprocating threading of long stators and cracking of potting compound.

[0048] Comparative Example 4 Referring to Example 1, the difference is that the three-stage stepped sintering is omitted and single-temperature sintering is used: sintering at 330°C for 35s under a nitrogen protective atmosphere; the remaining steps are the same as in Example 1, and the resulting electromagnetic wire is partially discharged and broken down under a high voltage of 3300V.

[0049] Comparative Example 5 The method of directly extruding 0.36mm PEEK onto copper conductors is not resistant to corona, has poor adhesion to copper, and is prone to cracking due to high internal stress. It cracks significantly after being immersed in oil at 250℃ / 30MPa, and is prone to electrical breakdown at 3300V. Therefore, it cannot be used as an electromagnetic wire for submersible motors.

[0050] Comparative Example 6 The PI surface sintering solution of 50% glass fiber + 50% polyester fiber, regardless of whether the outer layer is extruded or not, will crack significantly after oil immersion at 250℃ / 30MPa, and cannot be used as the electromagnetic wire of the submersible motor; in particular, after extruding the glass fiber reinforced polyether ether ketone layer, the problem of partial discharge will increase, and partial discharge and breakdown will be immediately triggered under 3300V high voltage.

[0051] Comparative Example 7 The product in step (3) of Example 1, i.e. omitting the outer layer, has its electromagnetic wires delaminated by oil immersion at 250°C and 30MPa, far from reaching 1000h.

[0052] Comparative Example 8 Existing technologies using glass fiber prepreg are unsuitable primarily due to the long curing time, typically exceeding 5 hours, which is unsuitable for winding production. Furthermore, the properties of the cured electromagnetic wire are difficult to meet the requirements of deep-sea submersible motors. In contrast, replacing the polyimide-coated glass fiber tape in Example 1 with existing glass fiber bismaleimide prepreg (35wt% resin), and after winding curing (180℃ / 1 hour + 200℃ / 2 hours + 220℃ / 2 hours + 240℃ / 2 hours) and low-temperature plasma treatment, followed by extrusion of the outer layer, resulted in electromagnetic wires that cracked after being threaded.

[0053] Comparison Example Referring to Example 1, the difference is that the polyimide glass fiber tape is omitted, resulting in electromagnetic wires with poor mechanical properties, which cannot be used for reciprocating threading of a 10-meter-long stator.

[0054] Currently, the performance of existing mainstream electromagnetic wires for 10-meter-class submersible motors faces bottlenecks. The main problems are cracking during potting and delamination after more than 8 reciprocating wire passes through the stator slots. These are urgent issues that need to be addressed in submersible motors. This invention boasts overall performance comparable to top-tier international 250℃~275℃ high-temperature electromagnetic wires, completely resolving the delamination problem at 250℃. It exhibits no partial discharge or breakdown under 3300V high voltage, has no air gap, is corona resistant, and has dense insulation. Reciprocating wire passes without damage, and it does not crack under long-term vibration. It is wear-resistant, stress-resistant, and fatigue-resistant. It is suitable for 10-meter-long stators, vacuum potting, and extreme conditions of 30MPa high-pressure oil immersion without cracking. Its reliability meets the long-term service requirements of deep-sea submersible motors. Both GF30-PEEK and LCP can be directly extruded, with mature processes suitable for mass production.

Claims

1. A high-temperature and high-voltage resistant circular composite insulated electromagnetic wire, comprising a conductor, characterized in that, It also includes an insulating layer; the insulating layer comprises, from the inside out, a polyimide film layer, a glass fiber tape layer, and an outer layer; the outer layer is a glass fiber reinforced polyether ether ketone layer or an aromatic polyester liquid crystal polymer layer; the glass fiber tape layer contains polyimide hot melt adhesive and has undergone plasma activation treatment.

2. The high-temperature and high-voltage resistant circular composite insulated electromagnetic wire according to claim 1, characterized in that, The polyimide film layer has a thickness of 0.1–0.15 mm, is wrapped bidirectionally in reverse with a 50%–53% overlap rate, and is sintered with nitrogen; the glass fiber tape layer has a thickness of 0.05–0.08 mm, with a wrapping overlap rate of 40–50%; and the outer layer has a thickness of 0.2–0.25 mm.

3. The method for preparing the high-temperature and high-voltage resistant circular composite insulated electromagnetic wire according to claim 1, characterized in that, Includes the following steps: (1) Wrap a polyimide film around the outer wall of the conductor; (2) Then wrap the glass fiber tape around it and sinter it; (3) Then, plasma activation treatment is used, and the outer layer is extruded to obtain a high temperature and high pressure resistant round composite insulated electromagnetic wire.

4. The method for preparing high-temperature and high-voltage resistant circular composite insulated electromagnetic wire according to claim 3, characterized in that, In step (1), a polyimide film is wrapped around the outer wall of the conductor using a bidirectional reverse wrapping method with a wrapping rate of 50% to 53%.

5. The method for preparing high-temperature and high-voltage resistant circular composite insulated electromagnetic wire according to claim 3, characterized in that, In step (2), the glass fiber tape is wrapped with a wrapping overlap rate of 40-50% and then sintered in nitrogen.

6. The method for preparing high-temperature and high-voltage resistant circular composite insulated electromagnetic wire according to claim 3, characterized in that, In step (3), argon / oxygen low-temperature plasma activation treatment is used, and then the outer layer is extruded to obtain a high-temperature and high-voltage resistant round composite insulated electromagnetic wire; the power of plasma activation treatment is 80-120W and the time is 15-25s.

7. An insulating layer for high-temperature and high-voltage resistant circular composite insulated electromagnetic wire, characterized in that, The insulating layer comprises, from the inside out, a polyimide film layer, a glass fiber tape layer, and an outer layer; the outer layer is a glass fiber reinforced polyether ether ketone layer or an aromatic polyester liquid crystal polymer layer; the glass fiber tape layer contains polyimide hot melt adhesive and has undergone plasma activation treatment.

8. A motor stator or motor, characterized in that, Includes the high-temperature and high-voltage resistant circular composite insulated electromagnetic wire as described in claim 1.

9. The application of the high-temperature and high-voltage resistant circular composite insulated electromagnetic wire according to claim 1 in the manufacture of motors.

10. The application of the high-temperature and high-voltage resistant circular composite insulated electromagnetic wire according to claim 1 in the preparation of deep-sea submersible motors.

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