EA004162B1 - Transformer core - Google Patents

Abstract

1. A transformer core, comprising three legs and yoke parts connecting said legs, wherein the cross-section of said legs is regularly multi-edged with more than four edges, characterised in that the core is made up of rings rolled from strips of constant width, wherein each of said rings make up part of two of said legs. 2. A transformer core according to claim 1, characterised in that said legs have hexagonal cross-section. 3. A transformer core according to claim 2, characterised in that it comprises nine rings. 4. A transformer core according to claim 3, characterised in that it comprises three rings of a first width and a first height and six rings of a second width corresponding to half the first width and a second height corresponding to half the first height. 5. A transformer core according to claim 4, characterised by a first (32), a second (33) and a third (34) ring-shaped part, wherein each ring-shaped part comprises a first ring (32a, 33a, 34a) wound from strips of a first width to a first height, the cross-sections of said rings being rhombic with two angles of 60 degrees, a second ring (32b, 33b, 34b) wound from a strip of a second width essentially corresponding to half the first width, to a second height essentially corresponding to half the first height, said second ring having rhombic cross-section and being positioned on said first ring (32a, 33a, 34a), a third ring (32c, 33c, 34c) wound from a strip of the second width to the second height, said second ring having rhombic cross-section and being positioned in one position on said first ring (32a, 33a, 34a) adjacent to said second ring and in another position on said second ring, said first, second and third ring-shaped part being assembled whereby a three-phase transformer core with three legs with hexagonal cross-sections is formed. 6. A transformer core according to claim 2, characterised in that it comprises seven rings. 7. A transformer core according to claim 6, characterised by a first (22a), a second (23a) and a third (24a) ring wound from strips of a first width to a first height, the cross-sections of said rings being rhombic with two angles of 60 degrees, said first, second and third rings forming yoke parts together forming a triangle, a fourth ring (24b) wound from a strip of said first width to a second height essentially corresponding to half the first height, said fourth ring having rhomboidal cross-section and being positioned on said third ring (24a; a fifth ring (22b; wound from a strip of a second width essentially corresponding to half the first width, to said first height, said fifth ring having rhomboidal cross-section and being positioned en said first ring (22a; a sixth ring (23b) wound from a scrip of the second width to said second height, said sixth ring having rhombic cress-section and being positioned on said second ring (23a), and a seventh ring (23c) wound from a strip of the second widen to said second height, said seventh ring having rhombic cross-section and being positioned on said second ring (23a) and on said sixth ring (23b), whereby a three-phase transformer core with three legs with hexagonal cross-sections is formed. 8. A transformer core according to claim 1, characterised in that said legs have octagonal cross-section. 9. A transformer core according to claim 8, characterised by a first, a second, and a third profile ring, each comprising three rings (42a, 42b, 42c) with two leg parts and two yoke parts, wherein a first ring (42a) having rhombic cross-section in its leg parts with an angle of 45 degrees and with the yoke parts bent 15 degrees in such a direction that the outer side faces of its leg parts are moved towards each other, a second ring (42b) having quadratic cross-sections in its leg parts and being positioned on said first ring, and a third ring (42c) having rhombic cross-sections in its leg parts, a first leg part having 45 degrees lying mainly on said first ring (42a) and a second leg part having 135 degrees lying on said second ring (42b), said first, second and third profile rings being assembled whereby a three-phase transformer core with three legs with octagonal cross-sections is formed. 10. A transformer core according to claim 1, characterised in that said legs have a cross-section with ten edges. 11. A transformer core according to claim 10, characterised by a first, a second, and a third profile ring, each comprising five rings (50a-e) with two leg parts and two yoke parts, wherein a first ring (50a) having rhombic cross-sections in its leg parts with an angle of 36 degrees, a second ring (50b) having rhombic cross-sections in its leg parts with an angle of 72 degrees, a third ring (50c) having rhombic cross-sections in its leg parts with an angle of 108 degrees, a fourth ring (50d) having rhombic cross-sections in its leg parts with an angle of 36 degrees and lying mainly on the first ring (50a) and having its yoke parts turned outwards 24 degrees, and a fifth ring (50e) having rhombic cress-sections in its leg carts with an angle of 144 degrees when it lies on the third ring (50c) but rhombic cross-section with an angle of 72 degrees when it lies outside the fourth ring (50c), and a channel (51) suitable for cooling the leg outside of the fifth ring (50e), said first, second and third profile rings being assembled whereby a three-phase transformer core with three legs with ten-sided cross-sections is formed. 12. A transformer core according to claim 11, characterised by cooling channels (52a, 52b, 53a, 53b) caused by giving the outer part of the third ring (50c) a rhombic cross-section with an angle of 72 degrees and by displacing another outer leg part of the third ring toward the fifth ring (50e) when it goes within the complete leg. 13. A transformer core according to claim 10, characterised by multi-edged cross-sections of their legs and profile rings comprising a first cluster of rings with rhombic cross-sections with different angles but in their leg parts turned the same angle and attached to the multi-edged cross-section, and inside a second cluster of rings with rhombic cross-section with different angles, but in their leg parts turned the same angle and attached to the first cluster and so on until innermost there arises space for rings, which in one of their leg parts is given a cross-section and turning differently from those in the other leg part. 14. A transformer core according to claim 1, characterised in that all rings have a rhombic cross-section with two angles of 60 degrees and two angles of 120 degrees. 15. A transformer core according to claim 1, characterised by an additional core (70) of strips between windings brought together at the top and the bottom of the core. 16. A transformer core according to claim 1, characterised by an additional core in the center line of at least one strip pole, and if many, arranged three and three in a package (figs. 8 and 9), which poles are bent to each yoke. 17. A transformer core according to claim 1, characterised in that segments between the cross-sections of the legs and a circumscribed circle are partly filled by thin rings and/or slightly broader strips.

Description

FIELD OF THE INVENTION

The present invention relates to transformer cores and, in particular, to three-phase transformer cores having rods with a cross section in the shape of a regular polygon.

State of the art

Three-phase transformer cores are usually made of transformer plates. In small transformers, the plates have a W-shaped profile, and in larger transformers, the cores are assembled from rectangular plates. Their disadvantage is that the magnetic field must pass from plate to plate through their edges, i.e., propagate not along the shortest path and not always in the direction of orientation of the magnetic lines.

Transformer developers sought to create core rods with a substantially circular cross section, since it provides the greatest efficiency for the assembled transformer. However, some compromise should always be chosen between efficiency and manufacturability, which leads to suboptimal cores with non-circular rods.

Until now, tape cores for three-phase transformers have been difficult to manufacture. The core efficiency can be improved by cutting out tapes of different widths and winding rings, which are given a circular cross section for single-phase transformers and a semicircular section for three-phase ones. This approach leads to a significant amount of waste, and the winding process becomes very time-consuming.

US Pat. No. 4,557,039 describes a method for manufacturing transformer cores using electrical steel tapes that taper at approximately a constant angle. By choosing a suitable angle at which the constriction occurs, it is possible to obtain core rods with a cross section in the form of hexagons or a higher degree of approximation of a circular cross section. However, tapes of decreasing width are complex and laborious to manufacture; however, the design of this core is unsuitable for large-scale production.

In FIG. 1, 1a, 1b, there is shown a known core of a three-phase transformer according to the aforementioned US patent No. 4557039. The cross section of the core as a whole has a triangular shape, as can be seen from its perspective image, and its three cores are connected by yokes. In FIG. 1a shows a cross section of a core before final assembly. The core contains three identical ring-shaped parts 12, 13, 14, a general view of which is shown in FIG. 1. Each annular part makes up half of one of the two rods having a hexagonal cross section (see Fig. 1a), so that only three rods of the core of the three-phase transformer are formed. The annular parts are first formed by winding from tapes of constant width to obtain three identical rings 12a, 13a, 14a having a rhombic cross section in which two angles are 60 ° and two angles 120 ° each. These rings 12a-14a correspond to the base rings. The orientation of the tapes is also visible from FIG. 1a, 1b.

Outside the base ring, each annular part 12a-14a has an outer ring 12b, 13b, 14b with a cross section in the shape of a regular triangle. Outer rings are wound from tapes with ever decreasing width.

As shown in FIG. 1b, when the three parts 12-14 are assembled together, they form three hexagonal rods on which transformer windings are wound.

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

The transformer cores are also described in the following documents: δΕ 163797, ϋδ 2458112, υδ 2498747, ϋδ 2400184 and I8 2544871. However, in the cores described in the listed documents, these problems are also not resolved.

SUMMARY OF THE INVENTION

The problem to which the present invention is directed is to create a transformer core in which energy losses are minimized.

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

A further task is to develop a method for manufacturing a transformer that meets the requirements of large-scale production.

The invention is based on the realization that a transformer core having one or more rods in the shape of a regular polygon with more than 4 sides can be obtained by winding from tapes of constant width.

According to the invention, a transformer core is created comprising three rods and yokes connecting said rods, the cross section of said rods having the shape of a regular polygon with more than 4 faces. The core is characterized in that it is made of rings wound from ribbons of constant width, each of which the rings forms part of two of these rods and yokes connecting the two rods.

Various preferred embodiments of the invention are defined in the dependent claims.

List of drawings

Next, a preferred embodiment of the present invention will be described in detail. The accompanying drawings form part of the description.

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

FIG. 1a and 1b are cross-sections of the core of FIG. 1 before and after assembly, respectively.

In FIG. 2 is a perspective view of the core of a three-phase transformer of the present invention with hex rods.

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

FIG. 3a and 3b are cross-sections of an alternative core of a three-phase transformer with hexagonal rods before and after assembly, respectively.

In FIG. 4 is a perspective view of the core of a three-phase transformer of the present invention with octagonal rods.

FIG. 4a is a cross section of the core of 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 shows a diagram of the variation of the leakage inductance and harmonics in a three-phase transformer.

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

In FIG. 12-14 show the cores 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.

Information confirming the possibility of carrying out the invention

Preferred embodiments of the core of the transformer of the present invention will now be described.

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

In FIG. 2 shows the core of the three-phase transformer of the present invention, designated generally as 20. It is similar in shape to the known transformer core of FIG. 1, i.e. has a deltoid cross section. However, its design is radically different from the known design.

The core is made of three parts 22,

23, 24 ring shape containing several rings. Rings with two different widths are used, i.e. wide and narrow rings. In this case, the narrow rings are made of tape having a half width compared to wide rings. In addition, the rings can be high or low, that is, they have one of two values in height, and the height of the low rings is half the height of the high rings. These ring definitions will be used throughout the rest of the description, unless otherwise specified. The tapes are preferably made from transformer steel sheets.

Each of the annular parts 22-24 contains a high base ring 22a-24a, respectively, similar to the rings described with reference to FIG. 1. Thus, these rings pairwise form the four sides of the hexagonal cores. The remaining rhombuses of the cores are performed in various ways (see Figs. 2a and 2b).

In the first rod 25 located in the background, an additional rhombic cross section is formed by two rhomboids. The first of these, designated 24b and belonging to the annular portion 24, is a wide low ring. The second, designated 22b and belonging to the annular portion 22, is a narrow high ring.

In the second core 26 located in FIG. 2 on the right, an additional rhombic cross section is formed by one rhomboid and two rhombuses. The rhomboid is filled with a narrow high ring 22b belonging to the annular part 22.

The rhombuses are filled with two narrow low rings 23b, 23c belonging to the annular part 23.

In the third rod 27 (on the left in FIG. 2), an additional rhombic cross section is also formed by one rhomboid and two rhombuses. The rhomboid is filled with a narrow high ring 24b belonging to the annular part

24. The rhombuses are filled with two narrow low low rings 23b, 23c belonging to the annular part 23. The reason that the annular part 23 contains two low narrow rings, instead of one larger ring, is that this larger ring cannot be narrow, and high (as required for the left shaft

27), and both wide and low (as required for the right shaft 26). As a result, two narrow low rings are used.

All the upper or lower yokes connecting the rods 25-27 have different profiles, but they are all built on the basis of 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 in accordance with two basic principles. Next, with reference to FIG. 3a and 3b, a second embodiment of the core will be described. The core, generally designated as 30, has a profile similar to that of the described first embodiment of the core. However, in the second embodiment, the core contains three identical annular parts 32-34, of which one will be described below (rightmost). The annular portions 32-34 are similar to the portion 23 described with reference to FIG. 2, wherein each annular portion comprises a wide and high main ring, respectively designated 32a-34a. In the first shaft 35, the portion 32 includes two narrow, low rings 32b, 32c, the ring 32c being wound outside the ring 32b. In the second shaft 36, part 32 includes two rings 32b, 32c arranged adjacent to one another (see FIG. 3a).

The other two parts 33, 34 are identical to part 32. Due to this, as a rule, simplification of core production is achieved, proportional to the volume of production, since the three ring parts 32-34 can be made according to one pattern.

Another option is to use wide low rings and to rotate the rods by 60 °, with the corresponding bending of the yoke details. In this case, the yokes will occupy an increased volume, and their bending is rather difficult to implement. It is also possible, although it is difficult, to use narrow high rings, provided they are turned and bent, as described above. Other options are also possible, including using smaller parts.

Next, with reference to FIG. 4 and 4a, an octagonal core core will be described. As can be seen from the example of the rod 45 located on the rear side, in the case of an octagonal section, the sides are turned 45 °, which means that they are located at an angle of 135 ° with respect to each other. Thus, three diamonds, each with an angle of 45 °, are located at the inner edges of the core rods. Outside of these rhombuses, two squares are filled with rings with a square cross section. The rest of the octagonal cross section of the rod is filled with a rhombus.

Of the six named sections of the cross section, three sections form a cross section of the profile ring extending to the second rod 46. The remaining sections form a cross section of the profile ring extending to the third rod 47. There is also a profile ring connecting the second and third rods 46, 47.

Each of the three profile rings contains two rings with the same parts forming the rod. The first ring 42a, 43a, 44a has a rhombic cross section and a part-arm bent by 15 °. The second ring 42b, 43b, 44b, located outside the first ring, has a square cross section and follows the shape of the first ring 42a-44a.

Similar to the solution used in the hexagonal rod variants shown in FIG. 2 and 3, two outer rhombuses make up the cross section of the outer ring with yokes bent 15 °. Alternatively, the two inner rhombuses form an inner ring, being bent 60 °. The next ring should provide the outer rhombus in one rod and the inner rhombus in the other and at the same time be bent 30 °. It is preferable to use profile rings of the same type, since it is difficult to bend the ring 60 °; in addition, it is not possible to do without a ring forming both the outer and inner rhombuses.

The third ring 42c included in part 42 has a rhombic cross section in the zones corresponding to the rods. In the rear rod 45, it occupies an external position, but is located inside the right rod 46. These rhombuses in the rod parts are formed by shifting the outer tapes of the ring to the right for the right rod 46 and to the left for the rear rod 45. Further, the rods rotate symmetrically by 30 ° and, accordingly, bend the yokes . The ring is attached with such a contour that it will lie outside relative to other rings. The final result is shown in FIG. 4.

Next, with reference to FIG. 5, a core with hexagonal rods will be described. All profile rings contain four rings with the same core parts. The first ring 50a, the second ring 50b, and the third ring 50c having a rhombic cross section in their rod parts are associated with the formation of a decagonal cross section. Accordingly, their angles are 36, 72 and 108 °, and their yokes are bent by 24 °. The fourth ring 506. having a rhombic section with an angle of 36 °, mainly lies on the first ring 50a. The rod parts of this ring are turned outward by 24 °, which leads to bending of the yokes by 48 °. In order to provide space for the fourth ring 506. it is required that the yokes of the third ring 50c be curved along a longer path.

Ί

The fifth ring 50e has a rhomboid cross section in its rod parts. In the zone where it is located outside the third ring 50c, the angle between its sides is 144 °, but in the zone where it is located outside the fourth ring 50th, this angle is 72 °. The yokes are bent only 12 °. Arrows ί in FIG. 5 indicate that cross sections 50e belong to different shaped rings. A channel 51 is also provided for cooling the rods. Alternatively, the channel is filled with a ring. This is an advantage 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 sections with an angle of 72 °, which leads to the formation of channels 52a and 52b. Other parts of the ring 50c to the right of the figure may be biased toward the ring 50e, which forms the channels 53a and 53b.

It is possible to form transformer cores with an even greater number of faces. In FIG. Figure 6 shows a 12-sided core, designated 60 as a whole. Profile rings consist of four 60-60th rings with rhombic cross-sections with angles of 30, 60, 90 and 120 °, which are connected with a 12-angle cross section and rotated by 15 °. Inside these rings there are two rings 60e, 60G with rhombic cross-sections with angles of 30 and 60 °, respectively, which are turned outward by 15 °. With the fifth and sixth rings 60e, 60G, there is connected a space for the ring 60d having a rhombic section with an angle of 30 °, turned outward by 45 °. Its second rod portion outside the sixth ring 60G is a rectangle turned outward by 15 °. On the ring 60th, space is provided for the ring 6011. having a rhombic section with an angle of 150 °, the second rod part of which is attached to the ring 60th and to the outer ring 60G. As a result, the entire cross section is filled. The yokes are spatially separated due to being bent along a longer path in order to provide space for other yokes.

For some transformer applications, the high performance of the described transformer cores can be further improved. This is illustrated in FIG. 7. The leakage 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. Tapes can be distributed around the entire primary winding or concentrated in one place, with the execution of the secondary winding eccentric.

Nonlinear magnetic properties of iron lead to harmonics in magnetic fields, voltages, and currents. Under perfectly symmetrical three-phase conditions and in the absence of distortion, the magnetic field will not act on an additional rod placed in the center of the core. However, common components in phase voltages such as third harmonics will experience the influence of a central rod.

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

In one embodiment of the invention, the central rod consists of three rectangular poles 80 made of tapes, the height of which is three times their width. The tapes are superimposed on each other with the formation of a square cross section, as shown in FIG. 8. The resulting profile has a substantially triangular shape; in this particular individual embodiment, poles with a rhombic cross section can be used. Three of these poles are combined with the formation of the package, in which the ends of the ribbons wave-like protrude relative to each other (see Fig. 9). Three packages are installed at a small distance from each other to form a core with a cross section approaching a triangular. The ends of the poles are bent outward so that they reach the yokes. To enable bending between the poles, it is necessary to place gaskets. The gaskets do not affect the magnetic properties, since for the formation of each yoke, one pole is bent from each packet 91a-s, 92a-s, 93a-s. In addition, the tapes, at least on one side, are parallel to the gaskets.

It is also useful to use a rod made by spiral winding from tapes, especially if 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 cores similar to those 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 zone of their contact. This makes it possible to rotate more significant flows in a triangle formed by yokes.

Based on the present invention, a core of a three-phase transformer with a linear arrangement of rods can also be obtained. The advantage of this scheme is that the transformer becomes narrower than in the case of the use of the deltoid core.

A transformer of this type is ideal, for example, for installation in railway cars.

In FIG. 11a shows a cross section of a transformer with octagonal rods. Each rod contains four diamonds with an angle of 45 ° and two squares. In this figure, the rings located between adjacent rods are visible, while the rings located between the outer rods are almost completely closed.

In order to manufacture transformer cores of this type, their core parts must be bendable, and the yokes must also be bendable so as to pass each other. This problem has several solutions, one of which is shown in the figure. The core parts of the rings are bent outward, and the parts of the yokes are inward or vice versa. The limited possibilities of plastic deformation impose restrictions on the shape of the parts that form the yoke; In addition, the yokes can be of any shape. FIG. 11 illustrates the realization of the idea of straight yokes with a sharp bend.

The rings can also be placed on top of each other in order to obtain smooth bends in order to save material.

The yoke between the left rod 115 and the central rod 116 is formed by a ring 112a having a rhombic section in the rod part, a ring 112b with a square section bent, like ring 112a, by 22.5 °, and a rhombic ring 112c, deployed in its rod parts on 67.5 °. Rings 112a and 112b fit into octahedrons near the location of the yokes, while ring 112c fits on the opposite side.

The yoke between the central shaft 116 and the right shaft 117 can only be in the central shaft, in the remaining sections 114a-c. Cross sections of the left and right rods are mirror images of the cross section of the central rod. Therefore, the rings passing through the central rod are symmetrical. The inner rings 114a, 114b have the most approximate positions in the right shaft 117. However, the ring 114c with a square section in the rod parts is most close to the square section in the right shaft. This is because the ring 113a with a square cross-section between the outer rods occupies an external position with respect to the existing yoke portions in order to be able to approach the left rod.

In some cases, it is not possible to provide a yoke reversal. As an alternative, a crease having a significant slope is used. This is illustrated by ring 114c having the shortest jumper. The fold begins at one end of the yoke and ends at its other end, indicated in FIG. 11, as 118a for the lower yoke and 118b for the upper yoke. In addition, the yokes can be divided into several narrow rings.

Single-phase transformers can also be made more efficient by using polygonal cross sections. In FIG. 12 shows a transformer with an octagonal cross section, formed by rings with the same cross sections, like three-phase transformers, but with reverse branches passing close to the outside of the windings. When transposing rings, you can also get an octagonal cross section. A slight reduction in the material consumption of the plates can be obtained, for example, by forming a loop to the left of the ring making the loop occupying in FIG. 12 extreme right position. In this case, the cross section should be changed to a rhombic, close to square.

A core with two rods can be obtained on the basis of three-phase schemes, by jointly bending the rings from one rod to form only one additional rod. In FIG. 13 shows a core having an octagonal cross section in its core parts. The turn of the three core parts is 45 °, and their bending is 90 °. A ring with a rectangular section and two rings lying outside with respect to it are not deformed. For cores with hexagonal rods, only three rings are required, made of tapes of the same width.

If the side of the octagon, where the three rhombic sides meet, occupies an internal position in the core, the turns will be only 22.5 °, with the exception of the rhombus in the middle, which should be turned 67.5 °. Replacing this rhombus with a ring with steps approximating the rhombus shown in FIG. 14 is more realistic. A further improvement is to enable the ribbons to reach the circumference, thereby increasing the total cross section.

Segments located outside the polygonal core can be filled with a thin rhombic ring made of tape, the width of which is equal to half the width, and the height is the full height of the segment, which is wound around its full width. Ribbon folds along the midline of the rhombus, similar to those shown in FIG. 15, convert two sides into one flat side in the form of a triangle, the sides of which are in contact with the core. A fold at the edge of the innermost tape, approximately 2/3 of its width and 8/9 of its height, forms a trapezoidal cross section as shown in FIG. 16. The cross section may also be rounded.

As shown in FIG. 17, 17a and 17b, using tapes of constant width, a cross-section close to the shape of a circle can be attached to the rod parts. As an example, the right shaft 172 of FIG. 17, with reference to FIG. 17a, which shows a section of this rod in a horizontal plane. The innermost part of the rod, about 80% of its full width and a height corresponding to 9% of its width, is made up of rings 173. There are three such rings that extend to the circumference describing them, as can be seen from FIG. 17a.

Four of the six segments were filled with magnetic material; other segments can be filled with ribbons located outside the assembled core.

Ring 174 may be placed on the outside of the hexagons.

In FIG. 17 shows another embodiment in which, in the outer rings, ring 174 has been replaced with wider tapes.

Some advantages of the transformer core of the present invention have already been mentioned. Among other advantages, you can specify the following: less load in idle mode; less weight; less volume, less electrical scattering, lower harmonics due to phase symmetry in a three-phase transformer, easy maintenance, etc.

The preferred embodiments of the transformer core of the present invention have been described above. One skilled in the art will understand that, without departing from the scope of the invention, various changes may be made to them.

Claims (17)

CLAIM 1. A transformer core containing three rods and a yoke connecting said rods, the rods having a cross-section in the shape of a convex polygon with a number of sides greater than four or close to the circumference of the polygon, characterized in that the core is formed from rings made from winding tapes constant width, each of these rings forms part of two of these rods and yokes connecting these two rods. 2. The core of the transformer according to claim 1, characterized in that said rods have a hexagonal cross section. 3. The core of the transformer according to claim 2, characterized in that it contains nine rings. 4. The core of the transformer according to claim 3, characterized in 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. 5. The core of the transformer according to claim 4, characterized in that it contains the first (32), second (33) and third (34) ring portions, each ring portion containing the first ring (32a, 33a, 34a) wound from the first tapes width to the first height, and this ring has a rhombic section with two angles of 60 °, the second ring (32L, 33b, 34b), wound from a tape of the second width, essentially corresponding to half the first width, to a second height, essentially corresponding to half the first height, and this ring has a rhombic section and superimposed on the specified first e ring, the third ring (32c, 33c, 34c), wound from a tape of second width to a second height, this ring has a rhombic cross section and is set to one position on said first ring (32a, 33a, 34a) adjacent to said second ring , and to another position on said second ring, with the assembly of said first, second and third ring portions forming a three-phase transformer core having three rods with a hexagonal cross section. 6. The core of the transformer according to claim 2, characterized in that it contains seven rings. 7. The core of the transformer according to claim 6, characterized in that it contains the first (22a), second (23a) and third (24a) rings, wound from ribbons of the first width to the first height, and these rings have rhombic sections with two angles of 60 ° and form a yoke, together forming a triangle, the fourth ring (24b), wound from a tape of said first width to a second height, essentially corresponding to half of the first height, moreover, said fourth ring has a rhomboid section and is superimposed on said third ring (24a), fifth ring (22b) wound from a belt w wide width, essentially corresponding to half of the first width, to the specified first height, with said fifth ring having a rhomboid section and superimposed on said first ring (22a), sixth ring (23b), wound from a tape of the second width, essentially corresponding to half of the first width , to the specified second height, moreover, said sixth ring has a rhombic section and is superimposed on said second ring (23a), seventh ring (23c), wound from a tape of second width to said second height, and said seventh ring has a rhombus It also has a cross section and is superimposed on said second ring (23a) and said sixth ring (23b). 8. The core of the transformer according to claim 1, characterized in that the said rods have an octagonal cross-section. 9. The transformer core of claim 8, characterized in that it contains the first, second and third profile rings, each of which contains three rings (42a, 42b, 42c) with two core parts and two yoke parts, the first ring ( 42a) in its core parts has a rhombic cross-section with an angle of 45 °, with its yoke parts bent by 15 ° in the direction ensuring that the outer lateral sides of its core parts are displaced towards each other, the second ring (42b) in its core parts has square sections and imposed on that The first ring, the third ring (42c) in its core parts has rhombic sections, and its first core part with an angle of 45 ° is mainly superimposed on the specified first ring (42a), and the second core part with an angle of 135 ° is superimposed on the specified second ring (42b), with the assembly of said first, second and third ring portions forming a three-phase transformer core having three rods with an octagonal cross section. 10. The core of the transformer according to claim 1, characterized in that said rods have a decagonal cross section. 11. The core of the transformer of claim 10, characterized in that it contains the first, second and third profile rings, each of which contains five rings (50a-50e) with two core parts and two yoke parts, the first ring (50a) in its core parts has rhombic sections with an angle of 36 °, the second ring (50b) in its core parts has rhombic sections with an angle of 72 °, the third ring (50c) in its core parts has rhombic sections with an angle of 108 °, the fourth ring (506 ) in its core parts has rhombic sections with an angle 36 ° and mainly superimposed on the first ring (50a), and its yoke parts are turned outward to 24 °, the fifth ring (50e) in its core parts has rhombic sections with an angle of 144 ° in the part that is imposed on the third ring (50c), and rhombic sections with an angle of 72 ° in the part that lies outside the fourth ring (506), and in the fifth ring there is a channel (51) for cooling the rod outside the fifth ring (50e), and the assembly specified , the second and third ring portions form the core of a three-phase trans rmator having three rods with a decagonal cross section. 12. The transformer core according to claim 11, characterized in that it has channels (52a, 52b, 53a, 53b) formed by giving the outer part of the third ring (50c) a rhombic section with an angle of 72 ° and shifting the other outer core part of the third ring to the side the fifth ring (50e) in its zone located inside the rod. 13. The core of the transformer of claim 10, characterized in that it contains rods with a polygonal cross section and profile rings containing the first group of rings with a rhombic cross section, having different angles, but unrolled in their core parts at the same angle, associated with a polygonal cross section and located inside the second group of rings with a rhombic cross section, having different angles, but rotated at their core parts at the same angle, associated with the first group of rings, and so on, until about there will be free space for the rings, which in one of the core parts has a cross-section and an angle of rotation different from those in the other core part. 14. The transformer core according to claim 1, characterized in that all the rings have a rhombic cross section with two angles of 60 ° and two angles of 120 °. 15. The transformer core according to claim 1, characterized in that it is provided with an additional core (70) formed of tapes located between the windings and grouped in the upper and lower parts of the core. 16. The core of the transformer according to claim 1, characterized in that it is provided with at least one additional core, located along the center line of at least one pole of the rod, and in the case of several additional cores, they are combined into a package (see Fig. 8 and 9), consisting of two groups of three cores, with the poles bent to each jumper. 17. The transformer core according to claim 1, characterized in that the segments between the cross sections of the rods and the circumference describing them are partially filled with thin rings and / or tapes of slightly greater width.