Foil winding transformer capable of saving insulation paper

Abstract

The utility model relates to the technical field of transformers, in particular to a foil winding transformer capable of saving insulation paper, which comprises an iron core column. An upper coil and a lower coil are wound on the iron core column; the upper coil comprises an upper inner winding wound on the top of the iron core column and an upper outer winding wound outside the upper inner winding; the lower coil comprises a lower inner winding wound at the bottom of the iron core column and a lower outer winding wound outside the lower inner winding; the upper inner winding and the lower inner winding are connected in series; and the upper outer winding and the lower outer winding are connected in series. According to the utility model, the total number of turns of the coil is divided into the upper part and the lower part for winding, the upper part and the lower part are respectively wound by half and then are connected in series, and the number of wound turns is reduced to half of the original number, so that the production efficiency is effectively improved; meanwhile, as the number of winding layers of the coil is reduced by half, the use amount of interlayer insulation paper is correspondingly reduced to half of the original use amount, and the material cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of transformers, in particular to a foil-wound transformer which saves insulation paper. Background Art

[0002] At present, small size, high power density and low cost are the directions of new product development of many transformer manufacturers and front-end customers. Improving the temperature resistance level of products is a good idea. With the increase of the allowable temperature rise of products, their volume can be made smaller and the amount of materials used will be reduced accordingly. However, there is a bottleneck that the higher the temperature resistance of the insulation material, the more expensive the unit price. Therefore, how to reduce the amount of insulation material without affecting the performance of the whole machine is also one of the important factors in reducing product costs. Utility Model Content

[0003] The utility model aims to provide a foil-wound transformer which saves insulation paper in view of the above-mentioned deficiencies in the prior art.

[0004] The purpose of the utility model is achieved through the following technical solutions: a foil-wound transformer that saves insulation paper, comprising an iron core column; the iron core column is wound with an upper coil and a lower coil; the upper coil comprises an upper inner winding wound on the top of the iron core column and an upper outer winding wound outside the upper inner winding; the lower coil comprises a lower inner winding wound on the bottom of the iron core column and a lower outer winding wound outside the lower inner winding;

[0005] The upper coil and the lower coil are wound in the same direction and at the same time;

[0006] The upper inner winding is connected in series with the lower inner winding, and the total number of turns after the series connection is the total number of turns of the secondary of the transformer, and the total number of turns is set to an odd number of turns; the upper outer winding is connected in series with the lower outer winding, and the total number of turns after the series connection is the total number of turns of the primary of the transformer, and the total number of turns is set to an odd number of turns.

[0007] The utility model is further configured that the upper inner winding, the upper outer winding, the lower inner winding and the lower outer winding are all wound by matching foil tape and interlayer insulating paper.

[0008] The utility model is further configured that the front end of the top of the core column is provided with an upper inner wire row; the rear end of the top of the core column is provided with an upper inner wire row, and the upper inner wire row passes through the lower inner winding and extends to the bottom of the core column;

[0009] A lower inner inlet wire row is provided at the rear end of the bottom of the core column; a lower inner outlet wire row is provided at the front end of the bottom of the core column, and the lower inner outlet wire row passes through the upper inner winding and extends to the top of the core column;

[0010] The upper inner outgoing wire row is connected in series with the lower inner incoming wire row;

[0011] The upper inner winding is arranged between the upper inner incoming wire row and the upper inner outgoing wire row, and is respectively welded thereto and then led out; the lower inner winding is arranged between the lower inner incoming wire row and the lower inner outgoing wire row, and is respectively welded thereto and then led out.

[0012] The utility model is further configured that the rear end of the top of the core column is provided with an upper external inlet line row; the front end of the top of the core column is provided with an upper external line row;

[0013] A lower external inlet line row is provided at the front end of the bottom of the core column; a lower external line row is provided at the rear end of the bottom of the core column, and the lower external line row passes through the upper external winding and extends to the top of the core column;

[0014] The lower external line bar is connected in series with the upper external line bar;

[0015] The upper external winding is arranged between the upper external incoming wire row and the upper outgoing wire row, and is respectively welded thereto and then led out; the lower external winding is arranged between the lower external incoming wire row and the lower outgoing wire row, and is respectively welded thereto and then led out.

[0016] The utility model is further configured that the core column includes a first core column, a second core column and a third core column; each core column is provided with an upper coil, a lower coil, an upper inner incoming wire row, an upper inner outgoing wire row, a lower inner incoming wire row, a lower inner outgoing wire row, an upper outer incoming wire row, an upper outer wire row, a lower outer incoming wire row and a lower outgoing wire row;

[0017] The top of the first core column, the top of the second core column and the top of the third core column are connected by an upper cross iron; the bottom of the first core column, the bottom of the second core column and the bottom of the third core column are connected by a lower cross iron.

[0018] The utility model is further configured such that the upper inner incoming wire row of the first core column, the upper inner incoming wire row of the second core column and the upper inner incoming wire row of the third core column are connected in parallel using n-wire connecting rows.

[0019] The utility model is further configured that the upper outer wire row passes through the lower outer winding and extends to the bottom of the core column and is connected to each other in pairs by using a D connection row;

[0020] Specifically, the lower end of the upper outgoing wire row of the first core column is connected to the lower outgoing wire row of the third core column; the lower end of the upper outgoing wire row of the second core column is connected to the lower outgoing wire row of the first core column; the lower end of the upper outgoing wire row of the third core column is connected to the lower outgoing wire row of the second core column; the connections are all connected in series using a D connecting row.

[0021] The utility model is further configured such that the width of the foil of the upper coil is equal to the width of the foil of the lower coil; the width of the foil is half of that of conventional products, and the thickness is twice that of conventional products.

[0022] The utility model is further configured such that a ventilation gap is provided between the upper coil and the lower coil;

[0023] The upper inner winding, the upper outer winding, the lower inner winding and the lower outer winding are all provided with air ducts.

[0024] The utility model is further configured that the front end of the upper cross iron is provided with a front upper clamping plate; the rear end of the upper cross iron is provided with a rear upper clamping plate; the front end of the lower cross iron is provided with a front lower clamping plate; the rear end of the lower cross iron is provided with a rear lower clamping plate;

[0025] An upper transverse locking bolt is provided between the front upper clamping plate and the rear upper clamping plate; a lower transverse locking bolt is provided between the front lower clamping plate and the rear lower clamping plate;

[0026] An upper pressing plate is arranged on the top of the upper cross iron; a lower blocking block is arranged on the bottom of the lower cross iron; and a longitudinal locking bolt is arranged between the upper pressing plate and the lower blocking block.

[0027] The beneficial effects of the utility model are as follows: 1. The utility model divides the total number of turns of the coil into two parts, an upper and a lower part, for winding. After half of the upper and lower parts are wound, the conductive bars are welded and led out to the outside in series, so that the number of turns is reduced to half of the original number, which effectively improves the production efficiency; at the same time, since the number of coil winding layers is halved, the amount of insulating paper used between layers is also reduced to half of the original number, which reduces the material cost; at the same time, the winding thickness is also reduced and the coil volume is reduced; 2. The utility model sets the number of primary and secondary turns of the transformer to an odd number of turns, and after dividing the upper and lower windings in half, a half-turn structure is presented, so that the series connection point is always on the back of the transformer and does not interfere with the user's wiring at the front end of the transformer, which is conducive to safety regulations and operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The utility model is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the utility model. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0029] Figure 1 It is a perspective view of the upper coil and the lower coil of the utility model;

[0030] Figure 2 It is a top view of the upper coil and the lower coil of the utility model;

[0031] Figure 3 It is a structural schematic diagram of the utility model;

[0032] Figure 4 It is a structural schematic diagram of another perspective of the utility model;

[0033] Figure 5 This is a schematic diagram of the structure of the hidden iron core column, the upper cross iron and the lower cross iron of the utility model;

[0034] Figure 6 The electrical principle diagram of the upper outer winding and the lower outer winding of the utility model;

[0035] Figure 7 This is an electrical schematic diagram of the cooperation between the upper inner winding and the lower inner winding of the utility model;

[0036] Among them: 11, the first core column; 12, the second core column; 13, the third core column; 14, the upper cross iron; 15, the lower cross iron; 2, the upper coil; 21, the upper inner winding; 22, the upper outer winding; 3, the lower coil; 31, the lower inner winding; 32, the lower outer winding; 41, the foil strip; 42, the interlayer insulating paper; 51, the upper inner incoming wire row; 52, the upper inner outgoing wire row; 53, the lower inner incoming wire row; 54, the lower inner outgoing wire row; 61. Upper external incoming line row; 62. Upper external incoming line row; 63. Lower external incoming line row; 64. Lower external incoming line row; 71. N line connection row; 72. D connection row; 81. Ventilation gap; 82. Air duct; 91. Rear upper clamping plate; 92. Front upper clamping plate; 93. Rear lower clamping plate; 94. Front lower clamping plate; 95. Upper transverse locking bolt; 96. Lower transverse locking bolt; 97. Upper top pressure plate; 98. Lower block; 99. Longitudinal locking bolt. DETAILED DESCRIPTION

[0037] The utility model is further described in conjunction with the following embodiments.

[0038] Depend on Figures 1 to 6 It can be seen that the foil-wound transformer for saving insulation paper described in this embodiment includes an iron core column; the iron core column is wound with an upper coil 2 and a lower coil 3; the upper coil 2 includes an upper inner winding 21 wound on the top of the iron core column and an upper outer winding 22 wound outside the upper inner winding 21; the lower coil 3 includes a lower inner winding 31 wound on the bottom of the iron core column and a lower outer winding 32 wound outside the lower inner winding 31;

[0039] The upper coil 2 and the lower coil 3 are wound in the same direction and at the same time. Since the foil strips have the same thickness, the speed of the windings is the same. The purpose of winding at the same time is to save time.

[0040] The upper inner winding 21 and the lower inner winding 31 are connected in series, and the total number of turns after the series connection is the total number of turns of the secondary side of the transformer, and the total number of turns is set to an odd number of turns; the upper outer winding 22 and the lower outer winding 32 are connected in series, and the total number of turns after the series connection is the total number of turns of the primary side of the transformer, and the total number of turns is set to an odd number of turns.

[0041] In the foil-wound transformer that saves insulation paper described in this embodiment, the upper inner winding 21 , the upper outer winding 22 , the lower inner winding 31 and the lower outer winding 32 are all wound by a foil strip 41 and an interlayer insulation paper 42 .

[0042] Specifically, in the foil-wound transformer that saves insulation paper described in this embodiment, the widths b1 and b2 of the interlayer insulation paper 42 are greater than the widths a1 and a2 of the foil tape 41, and the widths b1 and b2 of the interlayer insulation paper 42 exceed the foil tape 41 on both sides, thereby being able to effectively play an insulating role.

[0043] Through the above arrangement, during the manufacturing process, the upper coil 2 can be wound together with the lower coil 3, and the number of turns wound is half of the total number of turns; after the upper coil 2 (or the lower coil 3) starts to wind half a turn, the lower coil 3 (or the upper coil 2) starts to wind; correspondingly, at the end, after the upper coil 2 (or the lower coil 3) is wound, the lower coil 3 (or the upper coil 2) is wound another half turn; through the setting of this winding sequence, it can be ensured that the user terminal is in the front and the series connection is in the back without interfering with the wiring, that is, a half-turn structure is adopted, and the series connection point is set at the rear of the transformer.

[0044] In this embodiment, the total number of turns of the coil is divided into two parts, the upper and lower parts are wound half each and then connected in series, so the number of turns is reduced to half of the original number, thereby effectively improving the production efficiency; at the same time, since the number of coil winding layers is halved, the amount of interlayer insulating paper 42 is also reduced to half of the original number, thereby reducing the material cost.

[0045] In the foil-wound transformer that saves insulation paper described in this embodiment, the front end of the top of the core column is provided with an upper inner wire row 51; the rear end of the top of the core column is provided with an upper inner wire row 52, ​​and the upper inner wire row 52 passes through the lower inner winding 31 and extends to the bottom of the core column;

[0046] A lower inner inlet wire row 53 is provided at the rear end of the bottom of the core column; a lower inner outlet wire row 54 is provided at the front end of the bottom of the core column, and the lower inner outlet wire row 54 passes through the upper inner winding 21 and extends to the top of the core column;

[0047] The upper inner outgoing wire row 52 is connected in series with the lower inner incoming wire row 53;

[0048] The upper inner winding 21 is disposed between the upper inner incoming wire row 51 and the upper inner outgoing wire row 52, ​​and is respectively welded thereto and then led out; the lower inner winding 31 is disposed between the lower inner incoming wire row 53 and the lower inner outgoing wire row 54, and is respectively welded thereto and then led out.

[0049] Specifically, through the above arrangement, the upper inner winding 21 and the lower inner winding 31 are wound simultaneously and then connected at the upper inner outgoing wire row 52 and the lower inner incoming wire row 53, so that the tail of the upper inner winding 21 and the head of the lower inner winding 31 are connected in series.

[0050] In the foil-wound transformer for saving insulation paper described in this embodiment, the rear end of the top of the core column is provided with an upper external incoming wire row 61; the front end of the top of the core column is provided with an upper external wire row 62;

[0051] A lower external inlet line row 63 is provided at the front end of the bottom of the core column; a lower external line row 64 is provided at the rear end of the bottom of the core column, and the lower external line row 64 passes through the upper external winding 22 and extends to the top of the core column;

[0052] The lower outgoing line row 64 is connected in series with the upper incoming line row 61;

[0053] The upper outer winding 22 is disposed between the upper outer incoming wire row 61 and the upper outgoing wire row 62, and is respectively welded thereto and then led out; the lower outer winding 32 is disposed between the lower outer incoming wire row 63 and the lower outgoing wire row 64, and is respectively welded thereto and then led out.

[0054] Specifically, through the above arrangement, after the upper outer winding 22 and the lower outer winding 32 are wound simultaneously, the lower outer wire row 64 is connected to the upper outer incoming wire row 61 , so that the tail of the lower outer winding 32 is connected in series with the head of the upper outer winding 22 .

[0055] The present embodiment describes a foil-wound transformer that saves insulation paper, wherein the core column comprises a first core column 11, a second core column 12 and a third core column 13; each core column is provided with an upper coil 2, a lower coil 3, an upper inner incoming wire row 51, an upper inner outgoing wire row 52, ​​a lower inner incoming wire row 53, a lower inner outgoing wire row 54, an upper outer incoming wire row 61, an upper outer wire row 62, a lower outer incoming wire row 63 and a lower outer wire row 64;

[0056] The top of the first core column 11, the top of the second core column 12 and the top of the third core column 13 are connected by an upper cross iron 14; the bottom of the first core column 11, the bottom of the second core column 12 and the bottom of the third core column 13 are connected by a lower cross iron 15.

[0057] In the foil-wound transformer that saves insulation paper described in this embodiment, the upper inner incoming wire row 51 of the first core leg 11, the upper inner incoming wire row 51 of the second core leg 12, and the upper inner incoming wire row 51 of the third core leg 13 are connected in parallel using n-wire connecting rows 71. Specifically, through the above arrangement, all the inner windings of the transformer are connected in a Y-connection manner.

[0058] In the foil-wound transformer that saves insulation paper described in this embodiment, the upper outer wire row 62 passes through the lower outer winding 32 and extends to the bottom of the core column and is connected to each other in pairs using a D connection row 72;

[0059] Specifically, the lower end of the upper outgoing wire row 62 of the first core column 11 is connected to the lower outgoing wire row 63 of the third core column 13; the lower end of the upper outgoing wire row 62 of the second core column 12 is connected to the lower outgoing wire row 63 of the first core column 11; the lower end of the upper outgoing wire row 62 of the third core column 13 is connected to the lower outgoing wire row 63 of the second core column 12; the above connections are all connected in series using a D connection row 72. Through the above arrangement, all the outer windings of the transformer are D-connected.

[0060] In the foil-wound transformer that saves insulation paper described in this embodiment, the width and thickness of the foil tape 41 of the upper coil 2 and the foil tape 41 of the lower coil 3 are equal; the width of the foil tape 41 is half of that of conventional products, and the thickness is twice that of conventional products. The above arrangement ensures that the current density of the winding is consistent with that of conventional products, so that the product performance remains basically unchanged.

[0061] In the foil-wound transformer for saving insulation paper described in this embodiment, a ventilation gap 81 is provided between the upper coil 2 and the lower coil 3;

[0062] The upper inner winding 21, the upper outer winding 22, the lower inner winding 31 and the lower outer winding 32 are all provided with air ducts 82. The above arrangement can effectively dissipate heat.

[0063] In the foil-wound transformer for saving insulation paper described in this embodiment, the front end of the upper cross iron 14 is provided with a front upper clamping plate 92; the rear end of the upper cross iron 14 is provided with a rear upper clamping plate 91; the front end of the lower cross iron 15 is provided with a front lower clamping plate 94; the rear end of the lower cross iron (15) is provided with a rear lower clamping plate 93;

[0064] An upper transverse locking bolt 95 is provided between the front upper clamping plate 92 and the rear upper clamping plate 91; a lower transverse locking bolt 96 is provided between the front lower clamping plate 94 and the rear lower clamping plate 93;

[0065] An upper pressing plate 97 is provided at the top of the upper cross iron 14, a lower block 98 is provided at the bottom of the lower cross iron 15, and a longitudinal locking bolt 99 is provided between the upper pressing plate 97 and the lower block 98. The above arrangement makes the overall structure of the transformer stable and reliable.

[0066] To make it easier to understand, an example is given below:

[0067] There is a transformer, one of the windings of the original coil,

[0068] 1) The foil strip 41 is 0.6mm thick*400mm wide / 51 turns 60kg;

[0069] 2) The interlayer insulation paper 42 uses 0.14mm thickness * 420mm width / 51 turns 6.5kg;

[0070] After adopting the utility model, the coils are placed up and down, and the foil strips 41 of the upper and lower coil windings are the same. As mentioned above, the thickness is selected twice as much as before, 0.6*2=1.2mm, and the width is selected half of the previous one, 400 / 2=200mm, keeping the current density of the winding unchanged. In this way:

[0071] 1) The foil strip 41 is 1.2mm thick * 200mm wide / (upper 25.5 turns + lower 25.5 turns), about 60kg, and the total weight is basically unchanged. Here, the upper winding width is 200mm + the lower winding width is 200mm;

[0072] 2) The interlayer insulation paper 42 is 0.14mm thick * 215mm wide (upper 25.5 turns + lower 25.5 turns) / 3.26kg, where the upper winding width is 215mm + the lower winding width is 215mm. Compared with the previous 6.5kg interlayer insulation paper 42, the amount is reduced by about half, saving material costs.

[0073] Note: The reason for the reduction of insulation paper here is that the number of winding layers is reduced by half, so the amount of interlayer insulation paper 42 is also halved accordingly; after actually winding 25.5 turns, they are connected in series externally, and the winding time is reduced by half, which improves production efficiency;

[0074] In fact, it can also be understood in this way. The previous layer insulation used 0.14*420 / 51 turns / 6.5kg, and the current layer insulation is 0.14*430 (430 means 215+215) / 25.5T. Then, the current insulation paper usage can be calculated in proportion, 6.5kg / 420*430 / 52*25.5=3.26kg. 3.24kg is saved. If calculated at 380 yuan / kg, the cost is saved by 1231 yuan.

[0075] The following is a comparison of winding thickness. The previous winding thickness = (0.6 + 0.14) * 51 * 1.2 = 45.3 mm, where 1.2 represents the winding coefficient. Because the foil and paper cannot be completely close together, a coefficient must be multiplied in practice. In the present utility model, the winding thickness = (1.2 + 0.14) * 25.5 * 1.2 = 41 mm. 41 < 45.3. It can be seen that after the present utility model is adopted, the winding thickness of the coil becomes smaller, and the same core size can accommodate more windings, and the power density of the product can be improved. On the other hand, the average coil turn length will also become smaller due to the smaller winding thickness. In this way, the actual amount of foil tape used will also be reduced accordingly, and the internal resistance of the coil will also be reduced, which is beneficial to the reduction of the temperature rise of the product.

[0076] It can be seen from the above that the utility model not only reduces material costs, but also improves product performance and production efficiency.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit the protection scope of the utility model. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the utility model.

Claims

1. A foil-wound transformer that saves insulation paper, characterized in that: The invention comprises an iron core column; the iron core column is wound with an upper coil (2) and a lower coil (3); the upper coil (2) comprises an upper inner winding (21) wound on the top of the iron core column and an upper outer winding (22) wound outside the upper inner winding (21); the lower coil (3) comprises a lower inner winding (31) wound on the bottom of the iron core column and a lower outer winding (32) wound outside the lower inner winding (31); The upper coil (2) and the lower coil (3) are wound in the same direction; The upper inner winding (21) and the lower inner winding (31) are connected in series, and the total number of turns after the series connection is the total number of turns of the secondary of the transformer, and the total number of turns of the secondary of the transformer is set to an odd number of turns; The upper outer winding (22) and the lower outer winding (32) are connected in series, and the total number of turns after the series connection is the total number of turns of the primary of the transformer, and the total number of turns of the primary of the transformer is set to an odd number of turns.

2. The foil-wound transformer for saving insulation paper according to claim 1, characterized in that: The upper inner winding (21), the upper outer winding (22), the lower inner winding (31) and the lower outer winding (32) are all wound by combining foil tape (41) and interlayer insulating paper (42).

3. The foil-wound transformer for saving insulation paper according to claim 1, characterized in that: An upper inner wire row (51) is provided at the front end of the top of the core column; an upper inner wire row (52) is provided at the rear end of the top of the core column, and the upper inner wire row (52) passes through the lower inner winding (31) and extends to the bottom of the core column; A lower inner inlet wire row (53) is provided at the rear end of the bottom of the core column; a lower inner outlet wire row (54) is provided at the front end of the bottom of the core column, and the lower inner outlet wire row (54) passes through the upper inner winding (21) and extends to the top of the core column; The upper inner outgoing wire row (52) and the lower inner incoming wire row (53) are connected in series; The upper inner winding (21) is arranged between the upper inner incoming wire row (51) and the upper inner outgoing wire row (52), and is respectively welded to the upper inner incoming wire row (51) and the upper inner outgoing wire row (52) before being led out; the lower inner winding (31) is arranged between the lower inner incoming wire row (53) and the lower inner outgoing wire row (54), and is respectively welded to the lower inner incoming wire row (53) and the lower inner outgoing wire row (54) before being led out.

4. The foil-wound transformer for saving insulation paper according to claim 3, characterized in that: An upper external inlet line row (61) is provided at the rear end of the top of the core column; an upper external line row (62) is provided at the front end of the top of the core column; A lower external inlet line row (63) is provided at the front end of the bottom of the core column; a lower external line row (64) is provided at the rear end of the bottom of the core column, and the lower external line row (64) passes through the upper external winding (22) and extends to the top of the core column; The lower outgoing line row (64) is connected in series with the upper outgoing line row (61); The upper external winding (22) is arranged between the upper external incoming wire row (61) and the upper external wire row (62), and is respectively welded to the upper external incoming wire row (61) and the upper external wire row (62) before being led out; the lower external winding (32) is arranged between the lower external incoming wire row (63) and the lower external wire row (64), and is respectively welded to the lower external incoming wire row (63) and the lower external wire row (64) before being led out.

5. The foil-wound transformer for saving insulation paper according to claim 4, characterized in that: The core columns include a first core column (11), a second core column (12), and a third core column (13); each core column is provided with an upper coil (2), a lower coil (3), an upper inner incoming wire row (51), an upper inner outgoing wire row (52), a lower inner incoming wire row (53), a lower inner outgoing wire row (54), an upper outer incoming wire row (61), an upper outer wire row (62), a lower outer incoming wire row (63), and a lower outer wire row (64); The top of the first core column (11), the top of the second core column (12) and the top of the third core column (13) are connected via an upper cross iron (14); the bottom of the first core column (11), the bottom of the second core column (12) and the bottom of the third core column (13) are connected via a lower cross iron (15).

6. The foil-wound transformer for saving insulation paper according to claim 5, characterized in that: The upper inner incoming wire row (51) of the first core column (11), the upper inner incoming wire row (51) of the second core column (12), and the upper inner incoming wire row (51) of the third core column (13) are connected in parallel and led out through an n-wire connection row (71).

7. The foil-wound transformer for saving insulation paper according to claim 5, characterized in that: The upper outer conductor row (62) passes through the lower outer winding (32) and then extends to the bottom of the core column and is connected to a D connection row (72); The D connection row (72) of the first core column (11) is connected to the lower external incoming line row (63) of the second core column (12); the D connection row (72) of the second core column (12) is connected to the lower external incoming line row (63) of the third core column (13); and the D connection row (72) of the third core column (13) is connected to the lower external incoming line row (63) of the first core column (11).

8. The foil-wound transformer for saving insulation paper according to claim 2, characterized in that: The foil strip (41) of the upper coil (2) and the foil strip (41) of the lower coil (3) are equal in width and thickness.

9. The foil-wound transformer for saving insulation paper according to claim 1, characterized in that: A ventilation gap (81) is provided between the upper coil (2) and the lower coil (3); The upper inner winding (21), the upper outer winding (22), the lower inner winding (31) and the lower outer winding (32) are all provided with an air duct (82).

10. The foil-wound transformer for saving insulation paper according to claim 5, characterized in that: The front end of the upper cross iron (14) is provided with a front upper clamping plate (92); the rear end of the upper cross iron (14) is provided with a rear upper clamping plate (91); the front end of the lower cross iron (15) is provided with a front lower clamping plate (94); the rear end of the lower cross iron (15) is provided with a rear lower clamping plate (93); An upper transverse locking bolt (95) is provided between the front upper clamping plate (92) and the rear upper clamping plate (91); a lower transverse locking bolt (96) is provided between the front lower clamping plate (94) and the rear lower clamping plate (93); An upper pressing plate (97) is provided at the top of the upper cross iron (14); a lower blocking block (98) is provided at the bottom of the lower cross iron (15); and a longitudinal locking bolt (99) is provided between the upper pressing plate (97) and the lower blocking block (98).

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