UA54619C2 - Transformer core - Google Patents

Abstract

A transformer core comprises at least one leg and at least one yoke pan, wherein the cross section of the leg or the legs is regularly multi-edged with more than four edges. The core is made up of rings rolled from strips of constant width, whereby good electrical properties are achieved. The transformer is also easy to manufacture and avoids waste of material.

Description

Description of the invention

The field of technology to which the invention belongs.

The present invention relates to the core of transformers and, in particular, to the core of three-phase and single-phase transformers, which have rods with a cross-section in the form of a regular polygon.

Technical level

The core of three-phase transformers is usually made of transformer plates. In small transformers, the plates have a W-shaped profile, and in larger transformers, the core is assembled 710 from plates of rectangular cross-section, their disadvantage is that the magnetic field must pass from plate to plate through their edges, that is, spread not along the shortest path and not always in the direction of orientation of magnetic lines.

Transformer designers have sought to create core rods with an essentially circular cross-section because it provides the greatest efficiency for the assembled transformer. However, some compromise must always be made between efficiency 72 and manufacturability, which leads to a suboptimal core with non-round cores.

Until now, the strip core for three-phase transformers was difficult to manufacture. The efficiency of the core can be increased by cutting strips of different widths and winding rings, which are given a circular cross-section for single-phase transformers and a semi-circular cross-section for three-phase ones. This approach leads to a significant amount of waste, and the winding process becomes very time-consuming.

US patent Mo4557039 describes a method of manufacturing a transformer core using electrical steel tapes that taper at an approximately constant angle. Due to the selection of the appropriate angle at which the narrowing occurs, it is possible to obtain core rods with a cross-section that has the shape of hexagons or a higher degree of approximation of a circular cross-section. However, tapes of reduced width are difficult and time-consuming to manufacture; at the same time, the design of this core (He) is not adapted for large-scale production.

Fig. 1, Ta, 165 shows the well-known core of a three-phase transformer according to the specified US patent Mo4557039.

In cross-section, the core is generally triangular in shape, as can be seen from its perspective view, with its three cores connected by yokes. Fig.ta shows a cross-section of the core before final assembly. The core contains three identical parts 12, 13, 14 of an annular shape, the general appearance of which is shown in Fig. 1. Each ring part is half of one of the two rods, which have a hexagonal cross-section (see fig. ta), so that all three core cores of a three-phase ee, transformer are formed. "AND

The ring parts are first formed by winding from strips of constant width to obtain three 325 identical rings 12a, 13za, 14a, which have a rhombic cross-section in which two angles are 60" and two angles are 120". These rings 12a8-14a correspond to the base rings. The orientation of the tapes can also be seen from fig. Yes, 1 year

From the outside of the base ring, each ring part 12a-14a has an outer ring 120, 130, 146 with a cross section in the form of a regular triangle. The outer rings are made by winding from tapes with a constantly decreasing width. C 50 As shown in Fig. 1b, when the three parts 12-14 are assembled together, they form three hexagonal rods on which the transformer windings are wound.

The disadvantage of such a solution is that each size of the transformer requires a different cutting of the tapes. In addition, the outer rings 12-14 are made of tapes of decreasing width, which is associated with the appearance of waste. At the same time, the transformer becomes difficult to manufacture.

The core of transformers is also described in the following documents: ЖЕ 163797, ОБ 2458112, 05 2498747, 5 and 2400184 and 5 2544871. However, in the core described in these documents, the specified problems are also not "solved".

The essence of the invention b The task, the solution of which this invention is aimed at, is to create a transformer core in which energy losses are minimized.

The next task is to create a transformer core that is easy to manufacture and avoids significant material waste.

The further task is to develop a method of manufacturing a transformer that meets the requirements of large-scale production. 29 The invention is based on the realization that the core of a transformer, which has one or more rods in

GF) in the form of a regular polygon with the number of sides greater than 4, can be obtained by winding from strips of constant width. o According to the invention, a transformer core is created, which contains at least one rod and one yoke, in which the cross-section of the specified rod or rods has the shape of a regular polygon with 60 faces greater than 4, while the core is characterized by the fact that it is made of rings, wound from ribbons of constant width.

Various preferred embodiments of the invention are defined in the dependent clauses of the formula.

List of drawing figures

Next, a preferred embodiment of this invention will be described in detail. The attached drawings are part of the description.

Figure 1 shows a perspective view of a well-known core of a three-phase transformer made of rings with rhombic and triangular sections.

Figures 1a and 16 are cross-sections of the core of Figure 1 before and after assembly, respectively.

In fig. 2 is a perspective view of the core of a three-phase transformer according to the present invention with hexagonal cores.

Fig. 2a and 25 are cross-sections of the core of Fig. 2 before and after assembly, respectively.

Fig. Za and ZB are cross-sections of an alternative three-phase transformer core with hexagonal cores before and after assembly, respectively. 70 Fig. 4 shows a perspective view of the core of a three-phase transformer according to the present invention with octagonal cores.

Fig. 4a is a cross-section of the heart according to fig. 4.

Fig. 5 is a cross-section of a core with 10 sides.

Fig. 6 is a cross-section of a core with 12 sides.

In fig. 7-9 presents a scheme for changing the dissipation inductance and harmonics in a three-phase transformer.

Fig. 10 - cross-section of the core of a three-phase transformer with special yokes to improve the magnetic flux.

Fig. 11 - the core of a three-phase transformer with a linear arrangement of rods is presented.

Fig. 12-14 shows the core of a single-phase transformer according to the present invention.

Fig. 15-17 illustrate further improvements in the cross-sectional shape of the transformer core.

Next, preferred variants of the transformer core according to the present invention will be described.

Fig. 1 has already been discussed in connection with the known core and therefore does not require further consideration.

Figure 2 shows the core of a three-phase transformer according to the present invention, designated in general as 20.

Its shape is similar to the well-known transformer core shown in Fig. 1, that is, it has a delta-shaped cross-section. However, its design is radically different from the known design.

The core is made of three parts 22, 23, 24 of an annular shape, which each contain several rings. and)

Rings with two different width values are used, i.e. wide and narrow rings. At the same time, narrow rings are made of tape that is half the width of wide rings. Additionally, rings can be tall or short, i.e. have one of two height values, with the height of the low rings being half the height of the tall rings. These ring definitions will be used throughout the following description, except where specifically noted. The tapes are mostly made of sheets of transformer steel

Each of the annular portions 22-24 includes a tall base ring 22a-24a, respectively, similar to the rings described with reference to FIG. 1. Thus, these rings in pairs form four sides of a hexagonal core. Heart rhombuses that remain are made in different ways (Figs. 2a and 25). yu

In the first rod 25, located in the background, an additional rhombic cross-section is formed by two rhomboids. The first of these, labeled 246 and 24, which belongs to the ring part, is a wide, low ring. The second, labeled 225 and 22, which belongs to the ring part, is a narrow, tall ring. " 40 In the second core 26, located in Fig. 2 on the right, an additional rhombic cross-section pt") is formed by one rhomboid and two rhombuses. The rhomboid is filled with a narrow high ring 2260, which belongs to the annular part 22. The rhombuses are filled with two narrow low rings 230, 23c, which belong to the annular part ;" part 23.

In the third rod 27 (left in Fig. 2), an additional rhombic cross-section is also formed by one 45 rhomboid and two rhombuses. The rhomboid is filled with a narrow, high ring 246, which belongs to the ring part c 24. The rhomboids are filled with two narrow, low rings 236, 23c, which belong to the ring part 23. The reason why the ring part 23 contains two low, narrow rings, instead of one larger ring, is because this larger ring cannot be narrow and high (as is required for the left rod 27), and at the same time

Ge" wide and low (as required for the right rod 26). As a result, two narrow, low 50 Rings are used. - All upper or lower yokes that connect rods 25-27 have different profiles, but they are all built on

It is based on one base ring with a large rhombic cross section plus one ring with a rhomboid cross section or two rings with a small rhombic cross section.

The rhombic space outside the base rings can, of course, be filled according to two basic principles. Next, with reference to fig. Za and Zb, the second version of the core will be described. The core, generally designated as ZO, has a profile similar to the profile of the described first version of the core. However, in the second

Ф) version of the core contains three identical ring parts 32-34, one of which will be described below (far right). Ring parts 32-34 are similar to part 23, described with reference to fig. 2. In the first rod, the part 32 includes two narrow low rings 32B, 32c, and the ring 32c is wound from the outside of the ring Z2B. In the second rod 36, part 32 includes two rings 320, 32c, located adjacent to each other (see Fig. Za).

The other two parts 33, 34 are identical to part 32. Due to this, as a rule, a simplification of the production of the core is achieved, which is proportional to the volume of production, since the three ring parts 32-34 can be produced according to one template. 65 Another option is to use wide, low rings and turn the rods 60", ensuring the corresponding bending of the yoke parts. In this case, the yokes will occupy an increased volume, and their bending is quite difficult. It is also possible, although it is difficult, use narrow tall rings, provided they are turned and bent as described above.Other options are also possible, including the use of smaller parts.

Next, with reference to fig. 4 and 4a, a core with octagonal rods will be described. As can be seen in the example of the rod 45 located on the back side, in the case of an octagonal cross section, the sides are spread 45", which means that they are located at an angle of 135" in relation to each other. Thus, three rhombuses, each with an angle of 45", are located at the inner edges of the core rods. Outside these rhombuses, two squares are filled with rings of square cross-section. The rest of the octagonal cross-section of the /o rod is filled with a rhombus.

Of the six listed sections of the cross-section, three sections form the cross-section of the profile ring, which goes to the second rod 46. The other sections form the cross-section of the profile ring, which goes to the third rod 47. There is also a profile ring, which connects the second and third rods 46 , 47.

Each of the three profile rings contains two rings with identical parts that form a rod. The first ring 42a, 4za, 44a has a rhombic cross-section and the yoke parts bent 15". The second ring 4265, 43p, 440, located outside the first ring, has a square cross-section and follows the shape of the first ring 42a-44a.

Similar to the solution applied in the options with hexagonal rods shown in fig. 2 and C, the two outer diamonds form the cross-section of the outer ring with yokes bent 15".

Alternatively, the two inner diamonds form an inner ring by being bent 60". The next ring should provide an outer diamond in one rod and an inner diamond in the other and be bent 307". It is preferable to use profile rings of the same type, since it is difficult to bend the ring by 60"; in addition, it is impossible to do without a ring that forms both an outer and an inner rhombus. c

The third ring 42c, which is included in part 42, has a rhombic cross-section in the areas corresponding to the rods. In the rear rod 45, it occupies an external position, but is located inside the right rod i) 46. The specified rhombuses in the rod parts are formed by shifting the outer bands of the ring to the right for the right rod 46 and to the left for the rear rod 45. Next, the rods are turned symmetrically by 30" and respectively the yoke is bent. The ring is given such a contour that it will lie on the outside relative to the other rings. The final Ge!zo result is shown in Fig. 4.

Next, with reference to Fig. 5, a core with decagonal rods will be described. All profile rings contain four rings with the same core parts. The first ring 50a, the second ring 506, and the third ring 50c, which have a rhombic cross-section in their core portions, are connected to form a decagonal cross-section. Accordingly, their angles are 36", 72", and 108", and their yoke bent at 247. A fourth "ring 504, having a 36" diamond cross-section, rests substantially on the first ring 5ba. The rod portions of this ring are flared outward at 247, causing the yoke to be bent 48". To provide space for of the fourth ring 504, it is necessary that the yoke of the third ring 50s be bent along a longer trajectory.

The fifth ring 5O0e has a rhombic cross-section in its core parts. In the area where it is outside the third ring 50s, the angle of the diamond is 144", but in the area where it is outside the fourth ring 504, the angle of the diamond is 727. The yoke is bent only by 127. Arrows and in Fig. 5 indicate , that the cross-sections 50e belong to different profiled rings. A channel 51 is also provided, designated;" to cool the rods. Alternatively, the channel is filled with a ring. This is advantageous when the rings interact, allowing the magnetic field to propagate from one to the other. The channel space can be

Used, for example, in such a way that the upper part of the rings 50c acquires new rhombic intersections with an angle c of 727, which leads to the formation of channels 52a and 525. other parts of the ring 50c on the right of the figure can be displaced to the ring 50e, which forms the spaces 53a and 530 It is possible to form a transformer core with an even greater number of faces. Fig. b6 shows a 12-sided core, marked in general as 60. Profile rings

Ge" consist of four rings of bba-604 with rhombic cross-sections with angles of 30", 60", 90" and 120", which are connected to a 12-angle cross-section and are expanded by 15". Inside these rings are two rings bOe, - bOG with rhombic cross-sections with angles equal to 30" and 60", respectively, which are expanded

Ge) outwards at 157. With the fifth and sixth rings bOe, 60 is connected the space for the ring 609, which has a rhombic section with an angle of 30", expanded outwards by 45". Its second rod part outside the sixth ring 60" is a rectangle, expanded outwards by 15". On the ring 604 is provided a space for the ring BOI, which has a rhombic section with an angle of 150", the second rod part is attached to the bob ring and to the outer ring 6ОI. As a result, the entire cross section is filled. The yoke is spatially divided by

F) due to the fact that they are bent along a longer trajectory in order to provide space for other ravines. ka For some applications of transformers, the high characteristics of the described transformer core can be further improved. This is illustrated in Fig. 7. The dissipation inductance can be easily increased by using an additional core 29 wound from tapes and installed between the primary and secondary windings of the transformer. Ribbons are grouped at the top and bottom. The tapes can be distributed around the entire primary winding or concentrated in one place, with the secondary winding eccentric.

The non-linear magnetic properties of iron lead to harmonics in magnetic fields, voltages and currents. Under absolutely symmetrical three-phase conditions and in the absence of distortions, the magnetic field will not 65 Act on the additional rod placed in the center of the core. However, the common components in the phase stresses of the third harmonic type will experience the influence of the central rod.

It is also possible to use tapes between the windings and the central core.

In one of the variants of implementation of the invention, the central rod consists of three rectangular poles 80, made of tapes, the height of which is three times greater than their width. The strips are stacked on top of each other to form a square cross-section, as shown in fig. 8. The obtained profile has, in fact, a triangular shape; in this particular individual embodiment, rhombic cross-section poles may be used. Three such poles are combined to form a package, in which the ends of the tapes protrude relative to each other in a wave-like manner (see Fig. 9). The three packages are placed at a short distance from each other to form a core with a cross-section that approaches a triangle. The ends of the poles 70 are bent outward so that they reach the gaps. To ensure the possibility of bending, spacers must be placed between the poles. The spacers do not affect the magnetic properties, since one pole from each package 91a-z, 92a-z, 9UZa-z is bent to form each yoke. In addition, the tapes, at least on one side, are parallel to the spacers.

It is also useful to use a rod made by spirally winding tapes, especially if 7/5 There should be air gaps between the central rod and the yokes. In order to reduce these air gaps, the spiral can be made wider at the ends.

As can be seen from Fig. 10, the flexibility of the heart, similar to the one described, is good.

This figure shows the core described in connection with Fig.4. The main part of the magnetic flux can pass from one profiled ring to another through the rods, in the area of their contact. This provides an opportunity

Rotation of more significant flows in the triangle formed by the yokes.

On the basis of this invention, the core of a three-phase transformer with a linear arrangement of rods can also be obtained. The advantage of such a scheme is that the transformer becomes narrower than in the case of using a delta-shaped core. A transformer of this type is ideal, for example, for equipment in railway cars. with

Fig. 11a shows a cross-section of a transformer with octagonal rods. Each rod contains four 45" rhombuses and two squares. This figure shows the rings located between i) adjacent rods, while the rings located between the outer rods are almost completely closed.

In order to make a transformer core of this type, their core parts must be made with the possibility of bending, and the yokes must also be such that they can be bent to overlap each other. This problem would have several solutions, one of which is shown in the figure. The core parts of the rings are bent outward, and the parts of the yoke are bent inward or vice versa. The limited possibilities of plastic deformation impose restrictions on the shape of the parts, (7 forming the yoke; not taking this into account, the yokes can have any shape. Fig. 11 illustrates the implementation of the idea of straight yokes with a steep bend.

The rings can also be placed one on top of the other in order to obtain smooth curves in order to save material. yu

The yoke between the left rod 115 and the central rod 116 is formed by a ring 112a, which has a rhombic section in the rod part, a ring 1125 with a square section, bent, like the ring 112a, by 22.5", and a rhombic ring 112c, which is expanded in its rod parts by 67.5". The rings 112a and 1126 fit into the octahedrons near the yoke location, while the ring 112c fits on the opposite side. "

The yoke between the central rod 116 and the right rod 117 can be located only in the central z c rod, in the sections that remain 114a-z. The cross-sections of the left and right rods are mirror images

And reflections of the cross section of the central rod. Therefore, the rings that pass along the central rod, huh? symmetrical The inner rings 114a, 1146 have the closest positions in the right rod 117. However, the ring 114c with a square section in the rod parts is the closest to the square section itself

In the right rod. This is due to the fact that the ring 113a with a square section between the outer rods c occupies an outer position in relation to the yoke part, which is already there in order to be able to approach the left rod. o In some cases, it turns out to be impossible to ensure a reversal of the gap. As an alternative is used

Ge" fold, which has a significant slope. This is shown on the example of ring 114c, which has the shortest jumper. The fold 5p begins at one end of the yoke and ends at its other end, marked in Fig. 11 as 1184 for the lower yoke and as 1186 for the upper yoke. In addition, the yoke can be divided into several narrow rings.

Ge) Single-phase transformers can also be made more efficient if polygonal cross-sections are used. Fig. 12 shows a transformer with an octagonal cross-section, formed by rings with the same cross-sections as three-phase transformers, but with reverse branches that pass closely from the outside of the windings. An octagonal cross-section can also be obtained by transposing the rings. A small reduction in the material consumption of the plates can be obtained,

F) for example, by the formation of a loop to the left of the ring, which makes a loop that occupies in fig. 12 extreme right position. At the same time, the cross section should be changed to rhombic, close to square.

Cores with two rods can be obtained on the basis of three-phase circuits, by joint bending of rings from one rod with the formation of only one additional rod. In fig. 13 shows a core having an octagonal cross-section in its core portions. The turn of the three rod parts is 45", and their bending is 90". The ring with a rectangular cross-section and the two rings that lie outside of it are not deformed. For a core with hexagonal rods, you need only three rings, made of ribbons of the same width. 65 If the side of the octagon where the three rhombic sides meet is inward at the core, the turns will be only 22.5", except for the rhombus in the middle, which must be turned 67.5".

Replacing this rhombus with a ring with steps that approximate a rhombus is shown in fig. 14, is more realistic.

A further improvement is to enable the bands to reach a circle, thus increasing the total cross-section.

The segments that are outside the polygonal rod can be filled with a thin rhombic ring of tape, the width of which is half the width and the height is the full height of the segment, which is wound to its full width. Folds on the ribbons along the middle line of the diamond, similar to those shown in Fig. 15, transform the two sides into one flat side in the shape of a triangle, the sides of which are in contact with the core. A fold at the edge of the innermost tape, which is approximately 2/3 of its width and 8/9 of its height, forms a 70 trapezoidal cross-section shown in Fig. 16. The cross section can be rounded.

As shown in Fig. 17, 17a and 1706, using strips of constant width, the rod parts can be given a cross section close to the shape of a circle. As an example, the right rod 172 in Fig. 17 will be described, with reference to Fig. 17a, which shows the intersection of this rod with a horizontal plane. The innermost part of the rod, approximately 8095 from its full width and at a height corresponding to 995 from its /5 width, is made up of rings 173. There are three such rings that reach the circle describing them, as can be seen from Fig. 17a.

Four of the six segments were filled with magnetic material; other segments may be filled with ribbons that are outside the assembled core.

The ring 174 can be placed on the outer sides of the hexagons.

Fig. 17 shows another version of the implementation, in which the ring 174 was replaced by wider bands in the outer rings.

Some advantages of the transformer core according to the present invention have already been mentioned. Among other advantages, the following can be mentioned: lower loads in idle mode; less mass; smaller volume, less electrical dissipation, reduction of the level of harmonics due to phase symmetry in a three-phase transformer, simple maintenance, etc. with

The preferred variants of the transformer core according to the present invention were described above. One of ordinary skill in the art will understand that various changes may be made thereto without departing from the scope of the invention. and)

Claims (1)

Formula of the invention 30 0, , , , , 1. The core of a transformer, which contains three rods and yokes that connect said rods, and -- the rods have a cross-section in the form of a polygon with a number of sides greater than four, which differs in that the core is formed from rings made by winding from tapes of constant width, and each of said rings forms part of two of said rods. " 35 2. The transformer core according to claim 1, which differs in that the indicated rods have a hexagonal cross-section. Q. The transformer core according to claim 2, which is characterized by the fact that it contains nine rings. 4. The transformer core according to item C, which is characterized by the fact that it contains three rings having a first width and a first height, and six rings having a second width corresponding to half of the first width and a second height corresponding to half of the first height. with c 5. Transformer core according to claim 4, which is characterized in that it contains first (32), second (33) and third (34) ring parts, and each ring part contains a first ring (32a, ЗЗа, З4а) wound with tapes: from" the first width to the first height, and this ring has a rhombic section with two angles of 60", the second ring (325, 330, 345), wound from a tape of the second width, essentially corresponding to half of the first width, to the second HEIGHT, Essentially corresponding to half of the first height, and this ring has a rhombic cross-section and is superimposed on the first ring indicated on the left, the third ring (32s, ЗЗс, З4s), wound from a tape of the second width to the second height, and this ring has a rhombic cross-section and is installed in one position on the indicated first ring (32a, ЗЗа, З4a), adjacent to the indicated second ring, and to another position on the indicated second ring, and the assembly of the FO of the indicated first, second, and third ring parts forms the core of a three-phase transformer, which has 5p cores out of six angular cross-section. - 6. Transformer core according to claim 2, which differs in that it contains seven rings. Ge; 7. The transformer core according to claim 6, which is characterized in that it contains first (22a), second (23a) and third (24a) rings wound from tapes of a first width to a first height, and these rings have rhombic sections with two angles of 607 " and form a yoke, together forming a triangle, in the fourth ring (245), wound from a tape of the specified first width to the second height, essentially corresponding to half of the first height, and the specified fourth ring has a rhomboid cross-section and the third ring superimposed on the specified (Ф) 24a), the fifth ring (225), wound from a tape of the second width, essentially corresponding to half of the first GI width, to the specified first height, and the specified fifth ring has a rhomboid cross-section and is superimposed on the specified first ring (22a), the sixth a ring (235) wound from a tape of a second width, substantially corresponding in half of the first width, to the indicated second height, and the indicated sixth ring has a rhombic section and is superimposed on the indicated second ring (23a), a seventh ring (23c), wound from a tape friend o width to the indicated second height, and the indicated seventh ring has a rhombic section and is superimposed on the indicated second ring (23Za) and the indicated sixth ring (236). 8. The transformer core according to claim 1, which is characterized by the fact that the specified rods have an octagonal 65 cross section. 9. The transformer core according to claim 8, which is characterized by the fact that it contains first, second and third profile rings, each of which contains three rings (42a, 42b, 42c) with two rod parts and two yoke parts, while the first ring ( 42a) in its rod parts has a rhombic cross-section with an angle of 45", and its yoke parts, bent at 157 in a direction that ensures the displacement of the outer lateral sides of its rod parts towards each other, the second ring (425) in its rod parts has square cross-sections and superimposed on said first ring, the third ring (42c) has rhombic cross-sections in its core parts, with its first core part having an angle of 45", basically superimposed on said first ring (422) and the second core part having an angle of 135 " superimposed on the specified second ring (425), and the assembly of the specified first, second and third ring parts forms the core of a three-phase transformer, which has 7/0 three rods with an octagonal cross section . 10. The transformer core according to claim 1, which is characterized by the fact that the indicated rods have a decagonal cross section. 11. The transformer core according to claim 10, which is characterized by the fact that it contains first, second and third profile rings, each of which contains five rings (50a-50e) with two rod parts and two yoke /5 parts, while the first the ring (50a) in its rod parts has rhombic sections with an angle of 36", the second ring (505) in its rod parts has rhombic sections with an angle of 72", the third ring (50c) in its rod parts has rhombic sections with an angle of 108". the fourth ring (504) in its rod parts has rhombic sections with an angle of 36" and is generally superimposed on the first ring (50a), with its yoke parts, which are expanded outwardly by 24", the fifth ring (5be) in its rod parts parts has rhombic sections with an angle of 144" In the part that is superimposed on the third ring (50s), and rhombic sections with an angle of 72" in the part that lies outside the fourth ring (504), and the fifth ring has a channel ( 51) for cooling the rod, which is outside relative to the fifth ki (50e), and the assembly of the indicated first, second and third ring parts forms the core of a three-phase transformer, which has three rods with a decagonal cross section. with 12. The transformer core according to claim 11, which is characterized in that it has cooling channels (52a, 5260, 53a, 535), formed by providing the outer part of the third ring (50c) with a rhombic section with an angle of 72" and displacement i) of the other outer rod part of the third rings in the direction of the fifth ring (5bje) in its zone located inside the rod. 13. The transformer core according to claim 10, which is characterized by the fact that it contains rods with a polygonal transverse He! cross-section and profile rings, which contain the first group of rings with a rhombic section, which have different angles, but are expanded in their core parts to the same angle, associated with a polygonal cross-section (87 are located inside the second group of rings with a rhombic section, which have different angles, but expanded in their core parts to the same angle, connected to the first group of rings, and so on, until there is a free space inside for the rings, which in one of the core parts has a section and an angle of " , which differ from similar parameters in the other rod part 14. The transformer core according to claim 1, which is characterized in that all the rings have a rhombic section with two angles of 60" and two angles of 120". 15. The transformer core according to claim 1, which is characterized in that it is provided with an additional core (70) formed from tapes located between the windings and grouped in the upper and lower parts of the core. " 16. The transformer core according to claim 1, which is characterized by the fact that it is provided with at least one additional pt") with the core located along the central line of at least one pole of the rod, and in the case of the presence of several additional cores, they are combined into a package that consists from two groups of three cores, and the poles are bent to each jumper. 17. The transformer core according to claim 1, which is characterized by the fact that the segments between the cross-sections of the coils and the circle describing them are partially filled with thin rings and/or tapes of a slightly larger width. 1 sh» (22) - 50 3e) F) ime) 60 b5