High current water-cooled transformer for annealing

Abstract

The present invention relates to a high-current water-cooled transformer for annealing, comprising an iron core, a high-voltage coil and a low-voltage coil mounted on the iron core, and a main frame for erecting the iron core; the low-voltage coil is sandwiched in the middle of the high-voltage coil; the high-voltage coil and the low-voltage coil are arranged in close contact and high-temperature resistant insulating paper is placed between the high-voltage coil and the low-voltage coil; the low-voltage coil is stacked by a plurality of turns of copper bars that can conduct electricity and dissipate heat; high-temperature resistant insulating paper is placed between two adjacent turns of the copper bars; and a copper tube is welded closely to the outer periphery of the copper bars. The purpose of the present invention is to overcome the defects of the prior art and provide a high-current water-cooled transformer for annealing with a simple cooling structure, an adjustable coolant flow channel, the ability to reduce transformer operating energy consumption, and improve transformer operating efficiency.

Description

Technical Field

[0001] The invention relates to the field of high-current transformers, and in particular to a high-current water-cooled transformer for annealing. Background Art

[0002] As we all know, environmentally friendly products will be the main development trend in the future, and the research and development and large-scale adoption of eco-friendly cables have also become an international development trend. With the rapid popularization and promotion of eco-friendly cables, the production and processing pressure of cables has also increased.

[0003] At present, in the production and processing of cables, a high-current heating device that can efficiently anneal the copper wire is required during the annealing process of the cable conductor after drawing. The transformer is one of the key components of the high-current heating device, and the cooling efficiency can greatly affect the comprehensive performance of the transformer. However, the cooling structure of the transformer in the existing high-current heating equipment mostly uses several hollow wires in parallel, and the high and low voltage coils use independent water circulation cooling circuits respectively. The above cooling structure has the following defects: ① Due to the large loss of the transformer, the amount of cooling water required for the above cooling structure is also large; ② The high and low voltage coils use independent cooling circuits, which not only has a complex structure, but also increases the volume of the transformer; ③ The cooling stroke is long and the cooling efficiency is low; ④ The eddy current loss caused by the inability to achieve 100% complete transposition increases the operating energy consumption of the transformer and reduces the operating efficiency of the transformer. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a high-current water-cooled transformer for annealing which has a simple cooling structure, an adjustable coolant flow channel, can reduce transformer operating energy consumption and improve transformer operating efficiency.

[0005] The technical solution to achieve the purpose of the present invention is: a large current water-cooled transformer for annealing, comprising an iron core, a high-voltage coil and a low-voltage coil mounted on the iron core, and a main frame for mounting the iron core; the low-voltage coil is sandwiched in the middle of the high-voltage coil; the high-voltage coil and the low-voltage coil are arranged in close contact and high-temperature resistant insulating paper is placed between the high-voltage coil and the low-voltage coil; the low-voltage coil is formed by stacking multiple turns of conductive and heat-dissipating copper bars; high-temperature resistant insulating paper is placed between two adjacent turns of the copper bars; a copper tube is welded close to the outer periphery of the copper bar.

[0006] More preferably, the high-voltage coil is wound with a solid electromagnetic wire coated with an insulating coating and has a pancake-shaped structure with a through cavity in the center; the end surface of the high-voltage coil in contact with the low-voltage coil has a flatness of ≤10%.

[0007] More preferably, the radial dimension deviation of the high-voltage coil is ≤4%.

[0008] More preferably, the low-voltage coil is formed by stacking four turns of copper bars, and the thickness of the high-temperature resistant insulating paper placed between two adjacent turns of copper bars is 0.18 mm.

[0009] More preferably, two sheets of high temperature resistant insulating paper with a thickness of 0.18 mm are placed between the high voltage coil and the low voltage coil; the high voltage coil, the two sheets of high temperature resistant insulating paper and the low voltage coil placed in sequence are tightened and subjected to three varnishing treatments.

[0010] More preferably, insulating plates and bakelite bolts that cooperate with the insulating plates to clamp the high-voltage coil and the low-voltage coil are further installed on both sides of the high-voltage coil mounted on the upper and lower ends of the iron core.

[0011] More preferably, after tightening, the gap between the high-voltage coil and the low-voltage coil is 0.8 mm to 1.2 mm.

[0012] More preferably, one copper tube is welded to the outer periphery of each of the first and last turns of the copper bar in each group of the low-voltage coils; the copper tubes welded to the first and last turns of the copper bar in each group of the low-voltage coils are in parallel or series structure.

[0013] More preferably, the copper tubes in the series structure are connected by rubber tubes.

[0014] More preferably, the corner of each copper tube extends outwardly into a semicircular arc with a radius of 20 mm.

[0015] After adopting the above technical solution, the present invention has the following positive effects:

[0016] (1) The low-voltage coil in the present invention no longer uses a structure of multiple hollow wires in parallel, but is improved to a copper busbar and copper tube welding structure, which avoids the eddy current loss caused by the inability to achieve 100% complete displacement, reduces the operating energy consumption of the transformer, and improves the operating efficiency of the transformer; in addition, the copper busbar can both conduct electricity and dissipate heat, and the coolant circulates in the copper tube, while reducing the coil loss, the heat conduction function of the coolant is efficiently utilized to cool the coil; in addition, the copper busbar and copper tube welding structure effectively increases the cross-sectional area of ​​the high-voltage wire and reduces the wire resistance without increasing the volume of the transformer, thereby effectively reducing the heat loss during the operation of the transformer.

[0017] (2) In the present invention, the high-voltage coil is no longer designed with an independent cooling circuit. A high-temperature resistant insulating paper with excellent insulation performance is placed between the high-voltage and low-voltage coils. The high-voltage coil is in indirect contact with the low-voltage coil, and the heat generated during its operation is transferred to the coolant through the copper bus in the low-voltage coil, and finally taken out with the coolant. This structure in which the high-voltage and low-voltage coils share a cooling circuit reduces the size of the transformer.

[0018] (3) The copper tubes welded to the outer periphery of the copper busbar in the present invention can be connected in series or in parallel according to actual needs, so as to timely adjust the number of water inlet and outlet circuits of the transformer, thereby achieving better cooling effect and saving the use of coolant and reducing energy consumption.

[0019] (4) The arrangement of the semicircular arc at the corner of the copper tube in the present invention can prevent the internal stress of the copper tube caused by thermal expansion and contraction, thereby weakening the cooling effect and affecting the service life of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments and in conjunction with the accompanying drawings, wherein

[0021] Figure 1 It is an overall stereogram of the transformer of the present invention;

[0022] Figure 2 It is a front view of the transformer of the present invention;

[0023] Figure 3 A three-dimensional diagram of a coil assembly of the present invention;

[0024] Figure 4 A three-dimensional diagram of a low-voltage coil of the present invention;

[0025] Figure 5 A three-dimensional diagram of the copper busbar of the present invention;

[0026] Figure 6 A three-dimensional diagram of a high-voltage coil of the present invention;

[0027] Figure 7 This is a parallel cooling structure diagram of the present invention;

[0028] Figure 8 It is a series cooling structure diagram of the present invention;

[0029] Fig. 9 An exploded view of the coil assembly of the present invention;

[0030] Fig.10 It is a three-dimensional diagram of the iron core of the present invention.

[0031] The numbers in the accompanying drawings are: iron core 000, high-voltage coil 100, low-voltage coil 200, copper busbar 210, copper tube 220, rubber tube 230, main frame 300, high-voltage upper clamp 310, low-voltage upper clamp 320, high-temperature resistant insulating paper 400, insulating board 500, bakelite bolt 600. DETAILED DESCRIPTION

[0032] Example 1

[0033] See Figures 1 to 10The present invention includes an iron core 000, a high-voltage coil 100 and a low-voltage coil 200 mounted on the iron core, and a main frame 300 for erecting the iron core; the low-voltage coil 200 is clamped in the middle of the high-voltage coil 100; the above-mentioned main frame includes a pair of high-voltage upper clamps 310 and a pair of low-voltage upper clamps 320, and the specific installation structure between the high-voltage upper clamps 310 and the low-voltage upper clamps 320 and the iron core can adopt the existing fixing method; more specifically, the iron core 000 is composed of a plurality of stacked silicon steel sheets; the high-voltage coil 100 and the low-voltage coil 200 are arranged in close contact and a high-temperature resistant insulating paper 400 is placed between the high-voltage coil 100 and the low-voltage coil 200; the low-voltage coil 200 is stacked by multiple turns of conductive and heat-dissipating copper bars 210; a high-temperature resistant insulating paper 400 is placed between two adjacent turns of copper bars; a copper tube 220 is welded close to the outer periphery of the copper bar 210. The above-mentioned high-voltage coil 100 and low-voltage coil 200 are arranged in close proximity and high-temperature resistant insulating paper 400 is placed between the high-voltage coil 100 and the low-voltage coil 200 to enable the high-voltage coil to export heat to the low-voltage coil, and then the heat is uniformly brought out through the coolant in the copper tube welded outside the low-voltage coil, thereby realizing a shared cooling circuit for the high and low voltage coils.

[0034] Preferably in this embodiment, the high-voltage coil 100 is wound by a solid electromagnetic wire coated with an insulating coating and has a pancake-shaped structure with a through cavity in the center; the end surface of the high-voltage coil 100 in contact with the low-voltage coil 200 has a flatness of ≤10%, that is, the flatness of the surface where the high-voltage coil 100 and the low-voltage coil 200 are in contact needs to be ≤10%, which is used to ensure that the high-voltage coil 100 and the low-voltage coil 200 have sufficient fit, thereby ensuring that the heat of the high-voltage coil 100 can be discharged through the low-voltage coil 200.

[0035] In this embodiment, preferably, the radial dimension deviation of the high-voltage coil 100 is ≤4%, so as to ensure that it has a sufficient insulation distance from the copper tube 220 on the low-voltage coil 200. The above 4% means that, for example, the thickness of an insulated wire is 3.37 mm, and the theoretical radial dimension of 20 turns of wire is 20*3.37=67.4 mm, so the radial dimension of the wire coil in actual production should not exceed 67.4*1.04=70.1 mm.

[0036] Preferably in this embodiment, the low-voltage coil 200 is formed by stacking four turns of copper bars 210 and the high-temperature resistant insulating paper 400 placed between two adjacent turns of copper bars has a thickness of 0.18 mm. The 0.18 mm thick high-temperature resistant insulating paper 400 can ensure insulation between the turns of copper bars while also dissipating heat through the insulating paper, thereby preventing local overheating of the coil due to uneven heat dissipation.

[0037] Preferably in this embodiment, two sheets of high temperature resistant insulating paper 400 with a thickness of 0.18 mm are placed between the high voltage coil 100 and the low voltage coil 200; the high voltage coil 100, the two sheets of high temperature resistant insulating paper 400 and the low voltage coil 200 placed in sequence are tightened with tooling and placed in a vacuum pressure dipping equipment for three dipping treatments, so that they become a tightly fitted whole to ensure the heat conduction effect between the high and low voltage coils.

[0038] Preferably in this embodiment, both sides of the high-voltage coil 100 mounted on the upper and lower ends of the iron core are further provided with insulating plates 500 and bakelite bolts 600 that can clamp the high-voltage coil 100 and the low-voltage coil 200 together with the insulating plates 500. The insulating plates 500 and bakelite bolts 600 clamp the high-voltage coil 100 and the low-voltage coil 200 to ensure that the high and low voltage coils can fit tightly together, thereby ensuring good direct heat conduction between the high and low voltage coils. The high-voltage coil 100 and the low-voltage coil 200 located in the middle of the iron core 000 are limited by space and are pressed by a support plate between the coil and the iron core. The support plate pressing here can adopt an existing pressing installation structure.

[0039] More preferably in this embodiment, after tightening, the gap between the high-voltage coil 100 and the low-voltage coil 200 is 0.8 mm to 1.2 mm, preferably 1.0 mm to ensure that the heat conduction effect between the high-voltage and low-voltage coils is controlled in the best state.

[0040] Example 2

[0041] See Figure 4 On the basis of the above embodiment, in this embodiment, preferably, a copper tube 220 is welded on the outer periphery of the first and last turns of the copper bar 210 in each group of low-voltage coils 200, that is, two copper tubes 220 are welded on each group of low-voltage coils 200; the copper tubes 220 welded on the first and last turns of the copper bar 210 in each group of low-voltage coils 200 are in a parallel structure. When the transformer load is large and the coil temperature rise is high, a parallel structure is selected, that is, six water inlets are used, and each group of low-voltage coils 200 has two water inlet and outlet circuits.

[0042] Example 3

[0043] On the basis of the above embodiments, in this embodiment, preferably, a copper tube 220 is welded on the outer periphery of the first and last turns of the copper bar 210 in each group of low-voltage coils 200, that is, two copper tubes 220 are welded on each group of low-voltage coils 200; the copper tubes 220 welded on the first and last turns of the copper bar 210 in each group of low-voltage coils 200 are in a series structure. The copper tubes 220 in the series structure are connected by a rubber tube 230, and the rubber tube 230 and the copper tube 220 are locked and connected by a clamp for easy disassembly, wherein the clamp can adopt the existing structure. When the transformer load is small and the coil temperature rise is low, a series structure is selected, that is, a three-way water inlet is used, and each group of low-voltage coils 200 has an inlet and outlet water circuit.

[0044] Example 4

[0045] See Figure 4 On the basis of the above embodiments, in this embodiment, preferably, a semicircular arc with a radius of 20 mm is extended outward at the corner of each copper tube 220. The setting of the semicircular arc can prevent the internal stress of the copper tube due to thermal expansion and contraction, weaken the cooling effect, and affect the service life of the transformer.

[0046] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-current water-cooled transformer for annealing, comprising an iron core (000), a high-voltage coil (100) and a low-voltage coil (200) mounted on the iron core, and a main frame (300) for mounting the iron core; the low-voltage coil (200) is sandwiched between the high-voltage coil (100); characterized in that: The high-voltage coil (100) and the low-voltage coil (200) are arranged in close contact with each other, and a high-temperature resistant insulating paper (400) is placed between the high-voltage coil (100) and the low-voltage coil (200); the low-voltage coil (200) is formed by stacking a plurality of turns of copper bars (210) that can conduct electricity and dissipate heat; a high-temperature resistant insulating paper (400) is placed between two adjacent turns of the copper bars; and a copper tube (220) is welded closely to the outer periphery of the copper bars (210); The high-voltage coil (100) is wound from a solid electromagnetic wire coated with an insulating coating and has a pancake-shaped structure with a through cavity in the center; the end surface of the high-voltage coil (100) in contact with the low-voltage coil (200) has a flatness of ≤10%; The low-voltage coil (200) is formed by stacking four turns of copper bars (210), and the thickness of the high-temperature resistant insulating paper (400) placed between two adjacent turns of the copper bars is 0.18 mm; A copper tube (220) is welded to the outer periphery of the first and last two turns of the copper bar (210) in each group of the low-voltage coils (200); the copper tubes (220) welded to the first and last two turns of the copper bar (210) in each group of the low-voltage coils (200) are in a parallel or series structure.

2. A high current water-cooled transformer for annealing according to claim 1, characterized in that: The radial dimension deviation of the high-voltage coil (100) is ≤4%.

3. The high current water-cooled transformer for annealing according to claim 1, characterized in that: Two sheets of high-temperature resistant insulating paper (400) with a thickness of 0.18 m are placed between the high-voltage coil (100) and the low-voltage coil (200); the high-voltage coil (100), the two sheets of high-temperature resistant insulating paper (400) and the low-voltage coil (200) placed in sequence are tightened and subjected to three varnishing treatments.

4. A high current water-cooled transformer for annealing according to claim 1, characterized in that: Insulating plates (500) and bakelite bolts (600) that cooperate with the insulating plates (500) to clamp the high-voltage coil (100) and the low-voltage coil (200) are also installed on both sides of the high-voltage coil (100) mounted on the upper and lower ends of the iron core.

5. A high current water-cooled transformer for annealing according to claim 4, characterized in that: After tightening, the gap between the high-voltage coil (100) and the low-voltage coil (200) is 0.8 mm to 1.2 mm.

6. A high current water-cooled transformer for annealing according to claim 1, characterized in that: The copper tubes (220) in the series structure are connected via a rubber tube (230).

7. A high current water-cooled transformer for annealing according to any one of claims 1 to 6, characterized in that: A semicircular arc with a radius of 20 mm extends outward from the corner of each copper tube (220).

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