A coil casting method for rail transit vehicle transformer and reactor

Abstract

The present invention discloses a coil casting method for a rail transit vehicle transformer and reactor, comprising the following steps: S1, assembling an inner mold and applying a release agent; S2, wrapping the inner insulation layer of the coil inside the coil; S3, winding the coil; S4, airway insulation arrangement: wrapping the inner insulation layer of the coil airway, the outer insulation layer of the coil airway and placing an airway plate, and arranging an insulating partition between two adjacent airway plates; S5, wrapping the outer insulation layer of the coil, and firmly sealing the lower end of the outer insulation layer of the coil with the lower end of the structure obtained in step S4; S6, drying and preheating; S7, casting the coil in a vacuum environment using epoxy resin; S8, curing according to a curing temperature curve. The present invention has the advantages of simple steps, high processing efficiency, more economical cost, less pollution, and good insulation protection performance.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a rail transit vehicle-mounted transformer and a reactor, and in particular to a method for casting a coil of a rail transit vehicle-mounted transformer and a reactor. Background Art

[0002] The coils of traditional rail transit vehicle transformers and reactors are mostly made using the vacuum pressure dipping process. The vacuum pressure dipping process uses polyester insulating varnish, which can meet the requirements of outdoor operation of vehicle transformers and reactors. It has the advantages of simple process and no need for special molds. However, it also has some disadvantages. For example, the thin thickness of the insulating varnish leads to weak resistance to dirt, too many internal air gaps affect heat dissipation and are easy to absorb water. It cannot fully meet the harsh operating environment of rail transit vehicle products, such as large amounts of metal dust, rain and snow, and cannot meet special requirements such as drastic temperature changes, fire retardancy, and reliable insulation. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a coil casting method for rail transit vehicle-mounted transformers and reactors with simple steps, high processing efficiency, more economical cost, less pollution and good insulation protection performance.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A method for casting coils of a rail transit vehicle-mounted transformer or reactor, comprising the following steps:

[0006] S1, assemble the inner mold and apply the release agent;

[0007] S2, wrapping the inner insulation layer of the coil inside the coil;

[0008] S3, winding coil;

[0009] S4. Airway insulation arrangement: Wrap the inner insulation layer of the coil airway, the outer insulation layer of the coil airway and place the airway board, and set an insulating partition between two adjacent airway boards;

[0010] S5, wrapping the outer insulation layer of the coil, and firmly sealing the lower end of the outer insulation layer of the coil with the lower end of the structure obtained in step S4;

[0011] S6, drying and preheating;

[0012] S7, casting the coil using epoxy resin in a vacuum environment;

[0013] S8. Curing according to the curing temperature curve.

[0014] As a further improvement of the above technical solution: in step S1, a release agent is applied to the inner mold and then wrapped with a polyester film with a thickness of 0.03-0.1 mm.

[0015] As a further improvement of the above technical solution: in step S2, the insulation layer inside the coil is an insulation paper and glass ribbon layer.

[0016] As a further improvement of the above technical solution: in step S4, the coil airway inner insulation layer and the coil airway outer insulation layer are glass ribbon layers.

[0017] As a further improvement of the above technical solution: in step S4, the airway plate is an insulating paperboard or a glass fiber mesh cloth board.

[0018] As a further improvement of the above technical solution: in step S4, it also includes filling the upper and lower ends of the coil with flexible insulating paper strips or non-weft tapes.

[0019] As a further improvement of the above technical solution: in step S4, the thickness of the insulating partition is 1-4 mm.

[0020] As a further improvement of the above technical solution: in step S5, the outer insulation layer of the coil is a pre-impregnated tape layer and is firmly sealed by insulating glue.

[0021] As a further improvement of the above technical solution: in step S7, continuous pouring is performed under a vacuum degree of 200Pa-400Pa, and after the pouring is completed, the vacuum environment is maintained for 10-50 minutes.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] (1) The transformer and reactor coils of rail transit vehicles are processed by the casting process. Tests show that their insulation protection performance does not decrease at all under severe working conditions such as heavy dirt, moisture, water, ice and snow, thus avoiding the disadvantage of weak insulation protection performance of the vacuum pressure dipping process;

[0024] (2) After the inside of the coil is treated with epoxy resin vacuum casting, the overall thermal conductivity of the coil is greatly improved. Tests show that under the same conditions, the temperature rise is 10 to 20K lower than that of the vacuum pressure dipping process;

[0025] (3) The coil structure prepared by the present invention greatly improves the anti-cracking performance of the coil. Tests show that it can adapt to rapid temperature changes between -40°C and 180°C.

[0026] (4) The epoxy resin vacuum casting process has a high resin utilization rate and minimal waste; while the vacuum pressure dipping process has a large amount of diluent, which not only has a large amount of volatilization, but also has a large amount of dripping during the drying and curing process. The actual effective utilization rate is only 40-50%. Therefore, the overall cost of the epoxy resin vacuum casting process is more economical and less polluting;

[0027] (5) After adopting the vacuum casting process, the coil winding and wrapping process can be greatly simplified compared with the vacuum pressure dipping process, which can greatly improve the coil winding efficiency;

[0028] (6) Epoxy resin vacuum casting is easy to add fillers, which can ensure that the fire retardant requirements of rail transit are met;

[0029] (7) The epoxy resin vacuum casting coil has a compact structure, which can avoid the vibration of the turns in the leakage magnetic field and reduce the load noise of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the main structure of the coil processed by the coil casting method of the rail transit vehicle transformer and reactor of the present invention.

[0031] Figure 2 yes Figure 1 Schematic diagram of the top view structure.

[0032] Figure 3 yes Figure 1 Schematic diagram of the side structure.

[0033] The numbers in the figure represent: 1. Insulation layer inside the coil; 2. Insulation layer inside the coil airway; 3. Insulation layer outside the coil airway; 4. Airway plate; 5. Insulation partition; 6. Insulation layer outside the coil; 7. End insulation layer; 8. Lead tap. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Figures 1 to 3 An embodiment of a method for casting coils of a rail transit vehicle-mounted transformer and a reactor of the present invention is shown. The method for casting coils of a rail transit vehicle-mounted transformer and a reactor of the present embodiment comprises the following steps:

[0036] S1, assemble the inner mold and apply the release agent;

[0037] S2. Wrapping the inner insulation layer 1 inside the coil and arranging the inner insulation layer 1 inside the coil is conducive to ensuring that the cast insulation thickness is sufficient and improving the insulation reliability;

[0038] S3, winding coil;

[0039] S4, airway insulation arrangement: Wrap the coil airway inner insulation layer 2, the coil airway outer insulation layer 3 and place the airway plate 4, set an insulating partition 5 between two adjacent airway plates 4, set the coil airway inner insulation layer 2, the coil airway outer insulation layer 3, which is conducive to ensuring that the thickness of the cast insulation on both sides of the airway is sufficient, improving the insulation reliability, and the insulating partition 5 can ensure that the airway plates 4 are evenly spaced, while improving the anti-cracking performance of the epoxy resin;

[0040] S5, wrap the outer insulation layer 6 of the coil, and firmly seal the lower end of the outer insulation layer 6 of the coil with the lower end of the structure obtained in step S4, arrange the outer insulation layer 6 of the coil, and enhance the outer insulation casting thickness of the coil to be sufficient;

[0041] S6, drying and preheating;

[0042] S7, casting the coil using epoxy resin in a vacuum environment;

[0043] S8. Curing according to the curing temperature curve.

[0044] Furthermore, in step S1, a release agent is applied to the inner mold and then wrapped with a polyester film having a thickness of 0.03-0.1 mm. In this embodiment, the thickness of the polyester film is preferably 0.05 mm.

[0045] Furthermore, in this embodiment, in step S2, the inner insulation layer 1 of the coil is an insulating paper and glass fiber ribbon layer, and the insulation is reliable; wherein the coil conductor preferably adopts paper-wrapped wire or glass fiber-wrapped wire with good wettability to ensure the wettability of epoxy resin and turn insulation.

[0046] Furthermore, in this embodiment, in step S4, the coil airway inner insulation layer 2 and the coil airway outer insulation layer 3 are glass ribbon layers; the airway board 4 is an insulating cardboard or a glass fiber mesh cloth board to ensure the wettability of the epoxy resin and the interlayer insulation.

[0047] Furthermore, in this embodiment, step S4 also includes filling the upper and lower ends of the coil with flexible insulating paper strips or non-weft tapes, which is beneficial to ensure the wettability of the epoxy resin and the interlayer insulation, avoid excessive epoxy pouring, and avoid cracking during temperature shock.

[0048] As a preferred technical solution, in step S4, the thickness of the insulating partition 5 is 1-4 mm, and more preferably 2-3 mm, which is conducive to ensuring the uniformity of the airway gap and improving the temperature shock resistance of the airway insulation.

[0049] As a preferred technical solution, in this embodiment, in step S5, the outer insulation layer 6 of the coil is a pre-impregnated tape layer and is firmly sealed by insulating glue, so the coil does not need to be covered with an outer mold and can be directly cast and cured with an inner mold.

[0050] As a preferred technical solution, in this embodiment, in step S7, the epoxy resin meets the low-temperature impact resistance of -40°C and the glass transition temperature is greater than 120°. After the epoxy resin and the curing agent are mixed, they are continuously poured under a vacuum degree of 200Pa-400Pa. After the pouring is completed, it is kept in a vacuum environment for 10-50 minutes; the epoxy resin pouring height is preferably 2-5mm higher than the insulating filling layer at the upper end of the coil.

[0051] The coil obtained by the coil casting method of the rail transit vehicle transformer and reactor is:

[0052] (1) The transformer and reactor coils of rail transit vehicles are processed by the casting process. Tests show that their insulation protection performance does not decrease at all under severe working conditions such as heavy dirt, moisture, water, ice and snow, thus avoiding the disadvantage of weak insulation protection performance of the vacuum pressure dipping process;

[0053] (2) After the inside of the coil is treated with epoxy resin vacuum casting, the overall thermal conductivity of the coil is greatly improved. Tests show that under the same conditions, the temperature rise is 10 to 20K lower than that of the vacuum pressure dipping process;

[0054] (3) The coil structure prepared by the present invention greatly improves the anti-cracking performance of the coil. Tests show that it can adapt to rapid temperature changes between -40°C and 180°C.

[0055] (4) The epoxy resin vacuum casting process has a high resin utilization rate and minimal waste; while the vacuum pressure dipping process has a large amount of diluent, which not only has a large amount of volatilization, but also has a large amount of dripping during the drying and curing process. The actual effective utilization rate is only 40-50%. Therefore, the overall cost of the epoxy resin vacuum casting process is more economical and less polluting;

[0056] (5) After adopting the vacuum casting process, the coil winding and wrapping process can be greatly simplified compared with the vacuum pressure dipping process, which can greatly improve the coil winding efficiency;

[0057] (6) Epoxy resin vacuum casting is easy to add fillers, which can ensure that the fire retardant requirements of rail transit are met;

[0058] (7) The epoxy resin vacuum casting coil has a compact structure, which can avoid the vibration of the turns in the leakage magnetic field and reduce the load noise of the product.

[0059] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A coil casting method for a rail transit vehicle transformer or reactor, characterized in that: The following steps are involved: S1, assemble the inner mold and apply the release agent; S2, wrapping the inner insulation layer (1) inside the coil; S3, winding coil; S4, airway insulation arrangement: wrapping the coil airway inner insulation layer (2), the coil airway outer insulation layer (3) and placing the airway plate (4), and setting an insulating partition (5) between two adjacent airway plates (4); S5, wrapping the outer insulating layer (6) of the coil, wherein the outer insulating layer (6) of the coil is a pre-impregnated tape layer and the lower end of the coil is firmly sealed with the lower end of the structure obtained in step S4 by insulating glue; S6, drying and preheating; S7, casting the coil using epoxy resin in a vacuum environment; S8. Curing according to the curing temperature curve.

2. The coil casting method for rail transit vehicle transformer and reactor according to claim 1 is characterized in that: In step S1, a release agent is applied to the inner mold and then wrapped with a polyester film having a thickness of 0.03-0.1 mm.

3. The coil casting method for rail transit vehicle transformer and reactor according to claim 1, characterized in that: In step S2, the inner insulation layer (1) of the coil is an insulation paper and glass ribbon layer.

4. The coil casting method for rail transit vehicle transformer and reactor according to claim 3 is characterized in that: In step S4, the coil airway inner insulation layer (2) and the coil airway outer insulation layer (3) are glass ribbon layers.

5. The coil casting method for rail transit vehicle transformer and reactor according to claim 3 is characterized in that: In step S4, the airway plate (4) is an insulating paperboard or a glass fiber mesh cloth plate.

6. The coil casting method for a rail transit vehicle-mounted transformer or reactor according to any one of claims 3 to 5, characterized in that: Step S4 also includes filling the upper and lower ends of the coil with flexible insulating paper strips or non-weft tapes.

7. The coil casting method for a rail transit vehicle-mounted transformer or reactor according to any one of claims 3 to 5, characterized in that: In step S4, the thickness of the insulating partition (5) is 1-4 mm.

8. The coil casting method for a rail transit vehicle-mounted transformer or reactor according to any one of claims 1 to 5, characterized in that: In step S7, continuous pouring is performed under a vacuum degree of 200Pa-400Pa, and after the pouring is completed, the vacuum environment is maintained for 10-50 minutes.

9. The coil casting method for a rail transit vehicle-mounted transformer or reactor according to any one of claims 1 to 5, characterized in that: In step S7, the epoxy resin has a low temperature impact resistance of -40°C and a glass transition temperature greater than 120°.

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