High working field strength insulation structure of motor stator coil

Abstract

This invention belongs to the field of stator coil insulation technology, and specifically relates to a high-operating-field-strength insulation structure for motor stator coils. The technical solution is as follows: A high-operating-field-strength insulation structure for motor stator coils includes main insulation for the straight section covered on the electromagnetic wires of the coil slot, and further includes end-R-section reinforcing insulation and end-R-section main insulation wrapped sequentially from the inside to the outside on the electromagnetic wires of the coil end R-section. The main insulation for the straight section and the end-R-section main insulation include staggered, mixed, semi-overlapped glass cloth-reinforced low-adhesive mica tape and film-reinforced low-adhesive mica tape. The end-R-section reinforcing insulation is a glass cloth-reinforced polyimide film with adhesive mica tape or polyimide film semi-overlapped on the electromagnetic wires of the coil end R-section. This invention provides a high-operating-field-strength insulation structure for motor stator coils.

Description

Technical Field

[0001] This invention belongs to the field of stator coil insulation technology, and specifically relates to a high working field strength insulation structure for motor stator coils. Background Technology

[0002] Stator coil insulation technology is a key core technology of electric motors. The service life of a motor mainly depends on the life of the stator bar insulation, and the electrical performance of the stator coil main insulation plays a crucial role in the safe and reliable operation of the motor. The working field strength of the stator coil main insulation is the ratio of the motor's rated phase voltage to the thickness of the main insulation. The design value of the working field strength of the stator coil main insulation reflects the advancement of the motor's insulation design; the higher the working field strength and the thinner the coil main insulation thickness, the better the heat dissipation capacity of the main insulation.

[0003] The research results show that increasing the operating field strength of the stator coil main insulation by 30% (i.e., reducing the main insulation thickness by about 20% to 30%) increases the motor slot utilization rate by 17% to 25%, increases the motor efficiency by 0.1% to 0.3%, reduces the stator temperature rise by 3K to 8K, and reduces the motor weight by 5% to 15%. Reducing the thickness of the stator coil main insulation and increasing the operating field strength can effectively reduce the motor manufacturing cost, decrease the motor size, and solve a series of problems related to transportation and installation.

[0004] Currently, the main insulation of 6kV high-voltage motor stator coils in the industry is wrapped with 5 layers of mica tape, with a thickness of 1.30mm, and an operating field strength of 2.66kV / mm. For 10kV high-voltage motors, the main insulation is wrapped with 8 layers of mica tape, with a thickness of 2.0mm, and an operating field strength of 2.78kV / mm. These methods do not meet the efficiency and temperature rise requirements for high-efficiency motors. Therefore, it is necessary to develop a stator coil insulation structure with high operating field strength. This structure should further increase the operating field strength and reduce the thickness of the main insulation while maintaining the electrical strength of the stator coil main insulation. The aim is to increase the utilization rate of motor slots, reduce copper loss and mechanical losses, and ultimately improve motor efficiency. Summary of the Invention

[0005] In order to solve the above-mentioned problems in the prior art, the purpose of this invention is to provide a high working field strength insulation structure for motor stator coils.

[0006] The technical solution adopted in this invention is as follows:

[0007] A high working field strength insulation structure for motor stator coils includes main insulation for straight sections wrapped around the electromagnetic wires in the coil slots, and further includes end R-section reinforcement insulation and end R-section main insulation wrapped sequentially from the inside to the outside around the electromagnetic wires at the coil ends. The main insulation for straight sections and end R-section main insulation includes staggered mixed semi-overlapped glass cloth reinforced low-adhesive mica tape and film reinforced low-adhesive mica tape. The end R-section reinforcement insulation is glass cloth reinforced polyimide film with adhesive mica tape or polyimide film semi-overlapped around the electromagnetic wires at the end R-section of the coil ends.

[0008] As a preferred embodiment of the present invention, the material of the electromagnetic wire is a polyimide-fluorine 46 composite film sintered polyester film mica tape wrapped flat copper wire or a polyimide-fluorine 46 composite film sintered polyimide film mica tape wrapped flat copper wire.

[0009] As a preferred embodiment of the present invention, the insulation thickness of the electromagnetic wire is 0.40mm to 0.60mm.

[0010] As a preferred embodiment of the present invention, for a 6kV high-voltage motor, the end R-section reinforcement insulation is partially wrapped with one layer of glass cloth reinforced polyimide film or polyimide film from 10mm out of the stator core toward the coil end, and the wrapping length of the end R-section reinforcement insulation ranges from 60mm to 120mm; the end R-section main insulation includes 3.5 layers of glass cloth reinforced with less adhesive mica tape and film reinforced with less adhesive mica tape, which are interleaved and partially wrapped.

[0011] As a preferred embodiment of the present invention, for a 6kV high-voltage motor, the main insulation of the straight section includes 3.5 layers of glass cloth reinforced with less adhesive powder mica tape and film reinforced with less adhesive powder mica tape in a staggered mixed semi-overlapping manner, and the wrapping thickness of the main insulation of the straight section is 0.93mm.

[0012] As a preferred embodiment of the present invention, for a 10kV high-voltage motor, the end R-section reinforcement insulation is partially wrapped with 1-2 layers of glass cloth reinforced polyimide film or polyimide film from 10mm out of the stator core toward the coil end, and the wrapping length of the end R-section reinforcement insulation ranges from 80mm to 160mm; the end R-section main insulation includes 5.5-6.5 layers of glass cloth reinforced with less polyimide and film reinforced with less polyimide in a staggered mixed semi-overlapping manner.

[0013] As a preferred embodiment of the present invention, for a 10kV high-voltage motor, the main insulation of the straight section includes 5.5 to 6.5 layers of glass cloth reinforced with less adhesive powder mica tape and film reinforced with less adhesive powder mica tape in a staggered mixed semi-overlapping manner, and the main insulation wrapping thickness of the straight section is 1.46mm to 1.72mm.

[0014] As a preferred embodiment of the present invention, the main insulation of the straight section is covered with a groove anti-corona structure, which is a low-resistance anti-corona tape with a thickness of 0.06mm.

[0015] As a preferred embodiment of the present invention, the main insulation of the end R portion is covered with an end anti-corona structure, which is a high-resistance anti-corona tape with a thickness of 0.13mm; the end anti-corona structure is covered with a protective layer.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. This invention significantly improves the working field strength of the main insulation of the motor stator coil. The insulation structure has excellent electrical strength, effectively increases the stator slot fill factor, reduces motor size, reduces copper loss and mechanical loss, and lowers stator temperature rise, resulting in significant economic benefits.

[0018] 2. This invention increases the mechanical strength of the main insulation at the R end of the stator coil, effectively avoiding the risk of mechanical stress damage to the insulation in the slot opening area caused by straightening during stator coil lifting, transportation and winding, and improving the operational stability and reliability of the stator winding.

[0019] 3. Under the premise of ensuring the electrical performance of the stator coil insulation, this invention reduces the thickness of the main insulation of the stator coil and improves the working field strength of the main insulation. The number of mica tape wrapping layers of the main insulation of the 6kV motor stator coil is reduced from 5 layers to 3.5 layers, and the thickness is reduced from 1.30mm to 0.93mm, resulting in a 28.8% reduction in the thickness of the main insulation. The working field strength is increased from 2.66kV / mm to 3.75kV / mm, representing a 40.8% increase in working field strength. The efficiency of the 6kV high-voltage motor is increased by 0.1%, the temperature rise is reduced by 3K, and the motor weight is reduced by 12%, resulting in significant cost reduction and efficiency improvement.

[0020] 4. Under the premise of ensuring the electrical performance of the stator coil insulation, this invention reduces the thickness of the main insulation of the stator coil and increases the working field strength of the main insulation. The number of mica tape wrapping layers of the main insulation of the 10kV motor stator coil is reduced from 8 layers to 5.5 to 6.5 layers, and the thickness is reduced from 2.08mm to 1.46mm to 1.72mm, resulting in a 17.3% to 30.0% reduction in the thickness of the main insulation. The working field strength is increased from 2.78kV / mm to 3.36kV / mm to 3.97kV / mm, representing a 20.9% to 42.8% increase in working field strength. The efficiency of the 10kV high-voltage motor is increased by 0.1% to 0.2%, the temperature rise is reduced by 3K to 5K, and the motor weight is reduced by 11% to 16%, resulting in significant cost reduction and efficiency improvement.

[0021] 5. The present invention reduces the thickness of the anti-corona structure in the stator coil slots, further increasing the motor slot fill factor; it also reduces the thickness of the anti-corona structure at the stator coil ends, further increasing the gap at the stator winding ends and improving the motor's corona initiation voltage level. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the insulation structure of the coil slot;

[0023] Figure 2 This is a schematic diagram of the insulation structure at the R end of the coil;

[0024] Figure 3 This is a schematic diagram of the structure for reinforcing the insulation at the R end of the coil.

[0025] In the diagram: 1-Electromagnetic wire; 2-Main insulation of the straight section; 3-Anti-corona structure of the groove section; 4-Reinforced insulation of the end R section; 5-Main insulation of the end R section; 6-Anti-corona structure of the end; 7-Protective layer. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0028] like Figures 1-3 As shown, the high operating field strength insulation structure of the motor stator coil in this embodiment aims to reduce the thickness of the main insulation 2 in the straight section of the stator coil and increase the operating field strength of the main insulation 2 in the straight section without reducing the electrical performance of the main insulation. The operating field strength of the main insulation 2 in the straight section of the stator coil is increased to 3.97 kV / mm. Simultaneously, insulation reinforcement treatment is performed at the coil end R to improve the electrical strength at the end R, and the thickness of the low-resistance anti-corona layer and the high-resistance anti-corona layer is also reduced. This method is characterized by its simple operation and wide applicability, improving the stator slot fill factor, reducing motor size, reducing copper loss and mechanical losses, and lowering stator temperature rise.

[0029] The specific technical solution is as follows:

[0030] (1) The stator coil electromagnetic wire 1 uses a polyimide-fluorine 46 composite film sintered polyester film mica tape wrapped flat copper wire or a polyimide-fluorine 46 composite film sintered polyimide film mica tape wrapped flat copper wire with excellent electrical and mechanical properties. The insulation thickness of electromagnetic wire 1 is 0.40mm to 0.60mm.

[0031] (2) After the stator coil electromagnetic wire 1 is wound and formed, epoxy modified wire adhesive is applied to the straight part of the wire, and a 0.03mm polytetrafluoroethylene film is half-overlapped and wrapped. The straight part of the wire is then hot-pressed to improve the flatness of the wire. The hot pressing temperature is 170℃~190℃, and the heat preservation time is not less than 30 minutes.

[0032] (3) For a 6kV high-voltage motor, the main insulation 5 structure at the R end of the stator coil is as follows: Before wrapping the main insulation mica tape, first wrap the reinforcing insulation 4 at the R end. From 10mm out of the stator core towards the coil end, half-overlap one layer of glass cloth reinforced with polyimide film, incorporating mica tape or polyimide film, with a wrapping length ranging from 60mm to 120mm. Figure 3 As shown; at the end R part, the surface of the reinforcing insulation 4 is wrapped with the main insulation 5 at the end R part, and the main insulation 5 at the end R part is wrapped with 3.5 layers of glass cloth reinforced with less adhesive powder mica tape and film reinforced with less adhesive powder mica tape in an alternating mixed half-overlapping manner.

[0033] (4) For a 6kV high-voltage motor, the main insulation 2 structure of the straight section of the stator coil is as follows: the main insulation 2 of the straight section of the stator coil is wrapped with 3.5 layers of glass cloth reinforced with less adhesive powder mica tape and film reinforced with less adhesive powder mica tape in an alternating mixed half-overlapping manner. The main insulation wrapping thickness is 0.93mm, the mica tape wrapping tension is 50N~60N, and the main insulation working field strength is 3.75kV / mm.

[0034] (5) For a 10kV high-voltage motor, the main insulation 5 structure at the R end of the stator coil is as follows: Before wrapping the main insulation mica tape, first wrap the reinforcing insulation 4 at the R end. From 10mm out of the stator core towards the coil end, half-overlap 1-2 layers of glass cloth reinforced with polyimide film, incorporating mica tape or polyimide film, with a wrapping length ranging from 80mm to 160mm. Figure 3 As shown; at the end R part, the surface of the reinforcing insulation 4 is wrapped with the main insulation 5 at the end R part, and the main insulation 5 at the end R part is wrapped with 5.5 to 6.5 layers of glass cloth reinforcing low-adhesion mica tape and film reinforcing low-adhesion mica tape in an alternating mixed half-overlapping manner.

[0035] (6) For a 10kV high-voltage motor, the main insulation 2 structure of the straight section of the stator coil is as follows: the main insulation 2 of the straight section of the stator coil is wrapped with 5.5 to 6.5 layers of glass cloth reinforced with less adhesive powder mica tape and film reinforced with less adhesive powder mica tape in an alternating mixed half-overlapping manner. The wrapping thickness of the main insulation 2 of the straight section is 1.46mm to 1.72mm, the wrapping tension of the mica tape is 50 to 60N, and the working field strength of the main insulation is 3.36kV / mm to 3.97kV / mm.

[0036] (7) Stator coil slot anti-corona structure 3 uses a thinner low-resistance anti-corona tape, which is reduced from the conventional 0.09mm thick low-resistance anti-corona tape to 0.06mm thick low-resistance anti-corona tape, further increasing the motor slot fill factor.

[0037] (8) Stator coil end anti-corona structure 6 uses a thinned high-resistance anti-corona tape, which is reduced from the conventional 0.20mm thick high-resistance anti-corona tape to 0.13mm thick high-resistance anti-corona tape, further increasing the gap of the stator winding end bevel and improving the motor corona initiation voltage level.

[0038] (9) Before the stator coil is embedded into the iron core, the blank stator coil is cold-pressed using a cold pressing tool. The cold pressing size is 0.3mm to 0.5mm smaller than the iron core slot size.

[0039] (10) Before the blank stator coil is inserted, 0.08mm thick polyaramid fiber paper is used to protect the iron core slot. When inserting the coil, the stator coil is pressed into the iron core slot as a whole.

[0040] (11) After the stator coil is fully wound, it is vacuum pressure impregnated with an environmentally friendly solvent-free impregnating resin of heat resistance grade H. The impregnating resin is an environmentally friendly high-temperature impregnating resin composed of high-purity epoxy resin and high-temperature resistant resin, with a special latent curing agent. The viscosity is adjusted with low-viscosity hyperbranched unsaturated polyester, which has excellent "three-proof" performance.

[0041] (12) During the overall vacuum pressure impregnation process of the motor, monitor the change trend of the motor stator winding capacitance. Judge the motor stator winding insulation impregnation status based on the growth rate of the capacitance test curve. When the stator winding capacitance growth rate is ≤0.5% / h, the stator winding main insulation impregnation is good.

[0042] (13) After the vacuum pressure impregnation of the motor is completed, a rotary baking method is adopted to keep the impregnating resin in the main insulation of the stator winding, thereby improving the compactness of the main insulation of the stator winding. The rotary baking speed is 1r / min to 5r / min.

[0043] This invention significantly improves the working field strength of the main insulation of the motor stator coil. The insulation structure has excellent electrical strength, effectively increases the stator slot fill factor, reduces motor size, reduces copper loss and mechanical loss, and lowers stator temperature rise, resulting in significant economic benefits.

[0044] This invention increases the mechanical strength of the main insulation 5 at the R end of the stator coil, effectively avoiding the risk of mechanical stress damage to the insulation in the slot opening area caused by straightening during stator coil lifting, transportation and winding, and improving the operational stability and reliability of the stator winding.

[0045] This invention, while ensuring the electrical performance of the stator coil insulation, reduces the thickness of the main insulation of the stator coil and increases the working field strength of the main insulation. The number of mica tape wrapping layers of the main insulation of the 6kV motor stator coil is reduced from 5 layers to 3.5 layers, and the thickness is reduced from 1.30mm to 0.93mm, resulting in a 28.8% reduction in the thickness of the main insulation. The working field strength is increased from 2.66kV / mm to 3.75kV / mm, representing a 40.8% increase in working field strength. The efficiency of the 6kV high-voltage motor is increased by 0.1%, the temperature rise is reduced by 3K, and the motor weight is reduced by 12%, resulting in significant cost reduction and efficiency improvement.

[0046] This invention, while ensuring the electrical performance of the stator coil insulation, reduces the thickness of the main insulation of the stator coil and increases the working field strength of the main insulation. The number of mica tape wrapping layers of the main insulation of the 10kV motor stator coil is reduced from 8 layers to 5.5 to 6.5 layers, and the thickness is reduced from 2.08mm to 1.46mm to 1.72mm, resulting in a 17.3% to 30.0% reduction in main insulation thickness. The working field strength is increased from 2.78kV / mm to 3.36kV / mm to 3.97kV / mm, representing a 20.9% to 42.8% increase in working field strength. The efficiency of the 10kV high-voltage motor is increased by 0.1% to 0.2%, the temperature rise is reduced by 3K to 5K, and the motor weight is reduced by 11% to 16%, resulting in significant cost reduction and efficiency improvement.

[0047] The present invention reduces the thickness of the anti-corona structure 3 in the stator coil slot, thereby increasing the motor slot fill factor; it also reduces the thickness of the anti-corona structure 6 at the end of the stator coil, thereby increasing the gap at the end of the stator winding and improving the motor's corona initiation voltage level.

[0048] Example 1:

[0049] The high-operating-field-strength insulation structure and electrical performance of the main insulation of the stator coil of a 10kV high-voltage motor were measured. The insulation structure of the high-voltage motor stator coil in this embodiment is as follows: Figure 1 and Figure 2As shown, it includes the main insulation of the straight section covered on the electromagnetic wire 1 of the coil slot, and also includes the end R-section reinforcing insulation 4 and the end R-section main insulation 5 wrapped sequentially from the inside to the outside on the electromagnetic wire 1 of the coil end R section; the main insulation of the straight section and the end R-section main insulation 5 include glass cloth reinforced low-adhesive mica tape and film reinforced low-adhesive mica tape that are half-overlapped together, and the end R-section reinforcing insulation 4 is glass cloth reinforced polyimide film with adhesive mica tape or polyimide film that is half-overlapped on the electromagnetic wire 1 of the coil end R section.

[0050] The electromagnetic wire 1 is a flat copper wire wrapped with polyimide-fluorine 46 composite film sintered polyester film mica tape, with an insulation thickness of 0.60mm. The main insulation consists of epoxy glass low-resistance mica tape and polyimide film low-resistance mica tape wrapped alternately in a half-overlapping manner. The end R-section reinforcement insulation 4 is formed by half-overlapping two layers of glass cloth reinforcing polyimide film low-resistance mica tape from 10mm out of the stator core towards the coil end, with a wrapping length of 120mm. The slot anti-corona structure 3 is formed by half-overlapping one layer of low-resistance anti-corona tape on the surface of the main insulation in the coil slot. The end anti-corona structure 6 and the protective layer 7 are formed by half-overlapping one layer of high-resistance anti-corona tape and one layer of heat-shrinkable tape at the coil end. The high working field strength insulation structure of the 10kV high-voltage motor stator coil is shown in Table 1.

[0051] Table 1. Insulation structure for high working field strength of 10kV high voltage motor stator coil.

[0052]

[0053]

[0054] The main insulation of the stator coil slots was wrapped with 0.13mm×25mm thin-film mica tape and 0.14mm×25mm epoxy glass mica tape in an alternating half-overlap pattern on a fully automatic wrapping machine. The single-layer wrapping thickness of the main insulation was controlled at 1.59mm, and the working field strength of the main insulation was 3.63kV / mm. Vacuum pressure impregnation and baking curing were performed using an environmentally friendly solvent-free impregnation resin with a heat resistance rating of H. The electrical performance of the coil was tested and is shown in Table 2.

[0055] Table 2 Electrical performance of high operating field strength stator coils.

[0056]

[0057] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A high working field strength insulation structure for motor stator coils, characterized in that: The main insulation includes the straight section covering the electromagnetic wire (1) in the coil slot, and the end R section reinforcing insulation (4) and end R section main insulation (5) are wrapped from the inside to the outside on the electromagnetic wire (1) at the end R of the coil. The straight section main insulation and the end R section main insulation (5) include glass cloth reinforced low-adhesive mica tape and film reinforced low-adhesive mica tape wrapped in a half-overlapping manner. The end R section reinforcing insulation (4) is glass cloth reinforced polyimide film with adhesive mica tape or polyimide film wrapped in a half-overlapping manner on the electromagnetic wire (1) at the end R of the coil. For a 6kV high-voltage motor, the end R-section reinforcement insulation (4) is half-stacked with one layer of glass cloth reinforced polyimide film or polyimide film from 10mm out of the stator core toward the coil end. The wrapping length of the end R-section reinforcement insulation (4) is 60-120mm. The end R-section main insulation (5) includes 3.5 layers of glass cloth reinforced with less adhesive mica tape and film reinforced with less adhesive mica tape, which are half-stacked in an alternating manner. For a 6kV high-voltage motor, the main insulation of the straight section includes 3.5 layers of glass cloth reinforced with less adhesive powder mica tape and film reinforced with less adhesive powder mica tape, with a wrapping thickness of 0.93mm. For a 10kV high-voltage motor, the end R-section reinforcement insulation (4) is half-stacked with 1-2 layers of glass cloth reinforced polyimide film or polyimide film from 10mm out of the stator core toward the coil end, and the wrapping length of the end R-section reinforcement insulation (4) is 80mm-160mm; the end R-section main insulation (5) includes 5.5-6.5 layers of glass cloth reinforced with less adhesive mica tape and film reinforced with less adhesive mica tape, which are half-stacked in an alternating manner. For a 10kV high-voltage motor, the main insulation of the straight section includes 5.5 to 6.5 layers of glass cloth reinforced with less adhesive powder mica tape and film reinforced with less adhesive powder mica tape, with a thickness of 1.46mm to 1.72mm.

2. The high working field strength insulation structure for motor stator coils according to claim 1, characterized in that: The material of the electromagnetic wire (1) is a polyimide-fluorine 46 composite film sintered polyester film mica tape wrapped flat copper wire or a polyimide-fluorine 46 composite film sintered polyimide film mica tape wrapped flat copper wire.

3. A high working field strength insulation structure for a motor stator coil according to claim 2, wherein: The insulation thickness of the electromagnetic wire (1) is 0.40mm to 0.60mm.

4. The high working field strength insulation structure for a motor stator coil of claim 1, wherein: The main insulation of the straight section is covered with a groove anti-corona structure (3), which is a low-resistance anti-corona tape with a thickness of 0.06mm.

5. A high working field strength insulation structure for a motor stator coil as set forth in claim 1, wherein: The main insulation (5) at the end R is covered with an end anti-corona structure (6), which is a high-resistance anti-corona tape with a thickness of 0.13mm; the end anti-corona structure (6) is covered with a protective layer (7).

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