MXPA00001783A - Segmented transformer core - Google Patents

Abstract

A transformer core comprises a plurality of segments of amorphous metal strips. Each of the segments comprises at least one packet of the strips. The packet comprises a plurality of groups of cut amorphous metal strips arranged in a step-lap joint pattern. Packets thus formed can have C-shape, I-shape or straight segment-shape configurations. Assembly of the transformer is accomplished by placing at least two of the segments together. Core manufacturing is simplified and core and coil assembly time is decreased. Stresses otherwise encountered during manufacture of the core are minimized and core loss of the completed transformer is reduced. Construction and assembly of large core transformers is carried out with lower stress and higher operating efficiencies than those produced from wound core constructions.

Description

SEGMENTED TRANSFORMER NUCLEUS BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to transformer cores, and more specifically to transformer cores made from strips, ribbons or strips composed of ferromagnetic material. 2. DESCRIPTION OF THE PRIOR ART Transformers traditionally used in distribution, industrial, energy and dry type applications are usually of the coiled or stacked core variety. Winding core transformers are generally used in high volume applications, such as distribution transformers, since the rolled core design is conductive for mass production, automated manufacturing techniques. Equipment has been developed for winding or winding a ferro-agnostic core belt around and through the window of a multi-turn coil, preformed to produce a core and coil unit. However, the most common manufacturing procedure that includes the winding or stacking of the core independently of the preformed coils with which the core will eventually be bonded. The last arrangement requires that the core be formed with a joint for the wound core and multiple joints for the stacked core. The laminations of the core are separated in these joints to open the core, thereby allowing its insertion in the window (s) of the coil. Then the core is closed to redo the board. This procedure is commonly referred to as "linking" the core with the coil. A common process for the manufacture of a winding core composed of amorphous metal consists of the following steps: reeling of the strip, cutting of lamination, stacking of the lamination, wrapping of the strip, tempering and finishing of the edge of the core. The manufacturing process of the amorphous metal core, including the ribbon winding, lamination cutting, stacking of the lamination and wrapping of the tape is described in U.S. Patent Nos. 5,285,565; 5,327,806; 5,063,654; 5,528,817; 5,329,270 and 5,155,899. A finished core has a rectangular shape with the joint window in an extreme fork. The core segments are rigid and the joint can be open for insertion of the coil. The amorphous laminations have a thickness of approximately 0.025 mm. This causes the manufacturing process of the core of the amorphous metal cores to be relatively complex, compared to the manufacture of cores wound from steel material of the cold-rolled oriented grain composite (SiFe). The consistency in the quality of the process used to form the core from its annular shape in the rectangular shape depends to a large extent on the stacking factor of the amorphous metal lamination, since the overlaps of the joint need to match properly from one end to the other. the lamination to the other end in the form of "ladder". If the core formation process is not performed properly, the core may be overstretched in the core segment and the corner sections during the tape winding and core formation processes which will negatively affect the loss properties of the core. core and excitation force of the finished core. The core-coil configurations traditionally used in single-phase amorphous metal transformers are: core-type, consisting of a core, two core columns and two coils; of outer shell type, consisting of two cores, three core columns and one coil. The amorphous, three-phase metal transformer generally uses core-coil configurations of the following types: four cores, five core columns and three coils; three cores, three core columns and three coils. In each of these configurations, the cores have to be assembled together to align the columns and ensure that the coils can be inserted with adequate spaces. Depending on the size of the transformer, a multi-core matrix of the same size can be assembled for larger kVA sizes. The process of aligning the columns of the cores for the insertion of the coil can be relatively complex. In addition, in the alignment of the multiple columns of the core, the procedure used exerts additional stress on the cores as it flexes and bends each core column in position. This additional stress tends to increase core loss resulting in the finished transformer. The lamination of the core is fragile from the tempering process and requires additional care, time and special equipment to open and close the core joints in the process of assembly of the transformer. The breaking and scaling of the lamination is not easily avoided during this process of opening and closing the core seal. Containment methods are required to ensure that broken flakes do not enter the coils and create potential short circuit conditions. The induced stresses on the laminations during the opening and closing of the core joints sometimes cause a permanent increase of the core loss and the excitation power in the finished transformer.

SUMMARY OF THE INVENTION The present invention provides a transformer core construction that can be assembled from a plurality of core segments. Each of the core segments consists of at least one package of amorphous, cut metal ribbons. The package consists of a plurality of groups of amorphous, cut metal ribbons arranged in a splice joint pattern. The packages thus formed may have C-shaped, I-shaped or straight-segment configurations. The assembly of the transformer is done by placing at least two of the segments together. The construction is especially suitable for mounting three-phase transformers with three core columns and allows the construction of three-phase transformers having greater operating induction. Core fabrication and core assembly time is simplified and the coil decreases. The otherwise encountered stresses during core fabrication are minimized and the loss of the finished transformer core is reduced. The construction and assembly of large core transformers is done with less effort and greater operating efficiencies compared to those produced from winding core constructions BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood and other advantages will be apparent when reference is made to the following detailed description and the accompanying drawings, in which: Figure 1 is a side view of a reel wound in which an amorphous metal ribbon chosen to be cut into a group of tapes is received; Figure 2 is a side view of a cut group composed of a plurality of layers of amorphous metal tape; Figure 3 is a side view of a package consisting of a predetermined number of cut groups, each group being stepped to provide an indexed splice relative to the group immediately below it; Figure 4 is a side view of a core segment comprised of a plurality of packages, an overlap joint and a subsolated seal; Figure 5 is a perspective view of an inner package, the outer package, the segment C formed from a core segment, and a coating on the edge; Figure 6 is a perspective view of a segment I formed from a core segment; Figure 7 is a perspective view of a straight segment as formed from a core segment; Figure 8 is a perspective view of a phase-1 core made from two segments C and interlocking joint; Figure 9 is a perspective view of a type 1 outer shell made of four segments C; Figure 10 is a perspective view of the core segments of a three-phase / three-segment transformer core consisting of two segments C, one segment I and two straight segments; Figure 11 is a perspective view of a transformer core of three phases / three assembled segments and two straight segments; Figure 12 is a top plan view of a cross section of cruciform core and coil wound; Figure 13 is a sectional view of a rectangular core and rectangular coil; and Figure 14 is a dimensional view of a cross section of the cruciform core and the coil wound.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, the core segment of the transformer consists of a plurality of amorphous metal tape packages. Each packet 40 is constituted of a predetermined number of groups 20 of amorphous metal tapes and each group is constituted of at least one section of amorphous metal tapes 10 in multiple layers. The sections of the amorphous metal ribbons are made by cutting at controlled lengths a composite tape of multiple layer thickness of metal tape amorphous Each lamination group is arranged with its end in a spliced position 30. The lamination groups of the packages are arranged so that the stepped splice pattern within each package is repeated. The number of splices in each package can be the same or increased from the inner pack 41 to the outer pack 42. The core segment 50 is made up of the required number of rolling packets to meet the construction specification of the core segments. Segment C 60 is formed of a core segment 50 with adequate cutting length of the laminations from the inside to the outside to ensure that both ends of each package are substantially aligned once the segment is formed in its shape. The increase in the length of the cut is determined by the thickness of the grouping in rolling, the number of groups in each package and the separation of the necessary junction. The inner length of segment C is half the internal circumference of the full-size core plus clearances for separation of the joint at both ends of the rolling tapes. Segment C is produced by forming the core segment on a rectangular mandrel with dimensions suitable for fitting around the transformer coil. The segment I 70 is made up of two similar C segments 60. The segments C are coupled together in an adjoining configuration. One segment is arranged as the inverse reflection of the other segment. This means that for the sections of the upper and lower spliced joint one of the segments C has the joints spliced upwards and the other segment C has the joints spliced downwards. This configuration provides the means for one side of segment I to be the lower spliced joint 32 and the other side as the upper spliced joint 31. This is the preferred configuration for assembling the transformer core. The straight segment 80 is a core segment containing packages with equal lengths of the rolling cluster. The initial and final lengths for the respective groups of each package are the same. The profile position of the spliced joint is the same for each package of the lamination groups. The number of packets in a straight segment is determined by the segment construction required to comply with the magnetic area of the core of the particular induction operating in the transformer. Segment C 60, segment I 70 and straight segment 80 formed are tempered at temperatures of about 360 ° C while being subjected to a magnetic field. As is well known to those skilled in the art, the hardening step operates to release the stress in an amorphous metal material, including the stresses imparted during casting, winding, cutting, rolling, arranging, forming and shaping. The segment retains its shape after the tempering process. The edges of the segment, excluding the spliced joint area, are coated or impregnated with epoxy resin 61 to maintain lamination and packages together, and also to provide mechanical strength and support for the segment for subsequent coil assembly and Transformer manufacturing steps. The manufacturing process of these core segments, segment C 60, segment I 70 and straight segment 80 can be carried out with much more efficiency than the process traditionally used for the manufacture of amorphous metallic winding cores. The process traditionally used for cutting and stacking the lamination groups 20 and the packages 40 is carried out with a length cutting machine and the stacking equipment capable of positioning and arranging the groups in the shape of the joint 30. Processes of cutting, grouping and arranging lamination packages can be performed for individual packages in a manner similar to that of the current process. Depending on the size of the core design based on the kVA rating of the transformer for the amorphous metal winding core, the current cutting and stacking process may have a maximum cutting length or weight limit in manufacturing due to the feed capacity , cutting and handling of a machine. However, the core elements can be produced within the process and equipment capacity and assembled together for almost any transformer core size. In addition, as the size increases for the single amorphous metal winding core configuration, it is much more difficult to process, handle, transport and assemble transformer coils. Thus, multiple combinations of core segments, the C or l or straight can be assembled to form the complete wound core size. As a result, the segmented transformer core allows the use of amorphous metal belts in the application of large-sized transformers, such as power transformers, dry type transformers, SF6 type transformers and the like, in the range of 100 KVA to 500 MVA. The conventional amorphous metal winding core formation process requires a complex alignment process of the lamination groups and packages to wrap around a round / rectangular axis to form the spliced joints of each group and package. This process is carried out using some methods different from the existing practices such as a semi-automatic machine with nesting of belts that feeds and wraps individual groups and packages on a rotary axis or manual pressing and formation of the lamination of the core from a annular shape in the form of a rectangular core. In comparison, the process of forming the core segments 50 in segment C 60, segment I 70 and straight segment 80 can be performed more efficiently without the need to involve labor intensive or expensive automatic equipment. For the straight segment 80, the cut and stacked core segment 50 is fastened flat to the construction of the required stack and tied for annealing. For segment C 60, core segment 50 is formed and tied around a rectangular mandrel. The core segment is placed on the mandrel so that the ends of the joint 30 each are formed in the middle of the joint window of the complete core. This process can be done with the concept "die and matrix" with the mandrel being the die and the core segment placed in the matrix. As the mandrel is punched in the matrix with the core segment, segment C is formed. This can then be tied for annealing. The segment I 70 is formed with two C 60 segments, annealed, equivalent, the C segments are arranged so that one segment has its spliced joint located as superimposed 31, while the other segment with its spliced joint located as subsolapada 32. Both segments C are joined together in the section of the leg to form segment I. Also, this method of forming for different core segments imparts less stress to the core lamination compared to the method of manufacturing the amorphous metal winding core , traditional because it minimizes the traction forces in the corners of the core segment. Segment C 60, segment I 70 and straight segment 80 can be annealed with conventional heat treatment equipment such as batch or continuous ovens. The application of the magnetic field used in the annealing can be carried out by using circular current coils that provide a longitudinal magnetic field when the core segments are placed inside it. Since the profile of the segments is flat, it is also possible to use direct contact heating plates, practically and economically for the annealing. Also, the non-annular, flat shape of the segments will facilitate the improved annealing cycle with faster heating and cooling time compared to the conventional wound core. In addition, the annealing cycle time and temperature can be designed for individual core segments with different shape, size and properties in order to obtain an optimum level of material ductility and magnetic performance that is not easily obtained with winding amorphous cores. In effect, the core loss resulting from the core segments will be less than the conventional wound core from the lower stress induced during the core segment formation process and also the better stress release effect from the anneal. The reduction in the annealing cycle time will reduce the fragility of the laminations of the amorphous, annealed metal core segments. It will also reduce the cost of core annealing and reduce core loss resulting from annealed core segments. After annealing, the edges of segment C 60, segment I 70 and straight segment 80, excluding the region of the spliced joint, are finished with epoxy. The epoxy resin coating 51 is completed on both edges excluding the spliced joint regions to provide mechanical strength and surface protection for the transformer coil during the assembly process of the core segment and the coil. The epoxy coating can be applied for adhesion of the lamination surface or impregnation between laminations. Both methods are suitable for reinforcing the protection of the core segment and the surface. Two C 60 segments are used to assemble the single-phase core transformer 90. Four C 60 segments or two C 60 segments and one segment I 70 are used to fabricate the single-phase external jacket type design 100. The three-phase, three-legged transformer core 110 is constructed using two C 60 segments, one segment I 70 and two straight 80 segments. This three-phase construction has significant advantages over the three-phase, five-leg design of the traditional winding core. An induction of superior designs possible due to the same yoke construction of the core and leg. Less transformer losses are obtained through a three-leg design, due to the lower core leakage flow. The footprint of the transformer is reduced by having three core legs instead of five. The single-phase and three-phase transformer core configurations can be constructed with other possible combinations of segment C 60, segment I 70 and straight segment 80 not mentioned above. The construction and shape of segment C 60, segment I 70 and straight segment 80 makes it possible to assemble these segments in an "interlocking" mode 33 by inserting the segments together. Hence, the steps of the process that consume the time necessary to effect the opening and closing of the joints of the wound core are eliminated. The construction and shape of the segments allows each coil to be mounted on each segment individually instead of having to work on multiple core columns at a time. This "snap-fit" method greatly simplifies the work process for core and coil assembly. The additional time necessary to open and close the conventional winding core seal is eliminated. The management requirements are reduced, the destruction factor due to the loss of the core created by the transformer assembly process is reduced. Other benefits include significantly faster core and coil assembly time, better core and coil assembly quality due to reduced handling, and less dependence on complex transportation and assembly equipment such as stand-up machine and lift tables . Furthermore, since each segment is mounted independently with the coil, it is possible to mix and match the assembled segments based on their magnetic properties to optimize the operation of the finished transformer. An alternative method for assembling the coil in the transformer core consists of the step of directly winding the low and high voltage advantages directly on the core leg. This step is facilitated by the construction of the core segment. When the core segment is manufactured, each segment is formed and reinforced with bonding material coating. The mechanical strength of the core segment allows it to be used as a mandrel for the winding of the coil. Low and high voltage windows can be assembled directly on the core leg. The advantages resulting from this method of construction include less core mandrel tools, efficient design spaces between the core and the coil, better coil adjustment on the core leg and decrease in core stress and flaking of the joint . further, the alternative method for assembling the coil on the transformer described herein allows for a reduction in the use of material as well as labor required to assemble the core and the coils and better magnetic performance of the amorphous metal core segments. The simple, stack-like design of segment C 60, segment I 70 and straight segment 80 makes the manufacture of the amorphous metal transformer with a cross-shaped core cut 120 practical and economical instead of the traditional square / rectangular cut 121. Since each leg of the transformer core is made up of individual segments, multiple widths of amorphous ribbon segments can be assembled to form a segment C 60, segment I 70 or straight segment 80. Each core segment of ribbon width can be cut and individually stacked and assembled together before the training process. The formation process defines the final figure of the core segment and the entire segment with multiple lane widths can be annealed and the edge coated as already indicated. The core segment with cruciform cross-section 120 can be made of an amorphous strip with direct casting to the width or cut to width. The assembly process of the core segments and the coils will be the same as shown before. The advantages of the cruciform amorphous transformer core 120 include: the use of round coils 130 instead of rectangular coils 131, and maximizing the space filling factor of. the coil This will benefit many of the transformer manufacturers that currently only have winding technology for round coils. They will not have to invest in expensive winding machines for rectangular coils for use in the core of the amorphous metal transformer.

The construction of the core segment of the transformer of the present invention can be fabricated using numerous amorphous metal alloys. In general, alloys suitable for use in the construction of the transformer core segment of the present invention are defined by the formula: M70-85 Y5-20 Zo-20 / the subscripts in percent of atoms, where "M" is at least Fe, Ni or Co, "Y" is at least B, C or P, and "2" is at least Si, Al or Ge; provided that: (i) up to 10 percent of atoms of the "M" component can be substituted with at least one of the metallic species Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta or, and (ii) Up to 10 percent of the atoms of the components (Y + Z) can be substituted by at least one of the non-metallic species Im, Sn, Sb or Pb. These segments are suitable for use in voltage conversion and energy storage applications for distribution frequencies of about 50 to 60 Hz, as well as frequencies in the range of the giga-hertz. The products for which the segmented transformer core of the present invention is essentially suitable include: voltage, current and pulse transformers; inductors for linear power supply; power supply in circuit breaker mode; linear accelerators; devices for the correction of the energy factor; coils for the ignition of automobiles; for charging lamps; filters for EMI and RFI applications; magnetic amplifiers for power supplies in circuit breaker mode, devices for compression of the magnetic pulse and the like; These products that contain the segmented core can have power ranges starting from about one VA up to 10,000 VA and above. Having thus described the invention in complete detail, it will be understood that such details need not be strictly attached and that various changes and modifications may occur to those skilled in the art, all falling within the scope of the present invention as defined by the appended claims. .

Claims (23)

1. REI INDICATIONS A transformer core consisting of a plurality of amorphous metal tape segments, each segment comprising at least one package of these tapes.
2. A core segment containing a plurality of bundles of cut amorphous metal tapes.
3. The core segment as recited in claim 2, wherein each package contains a plurality of groups of cut amorphous metal ribbons arranged in a spliced joint pattern.
4. The core segment, as mentioned in claim 3, having a segment construction C, I or straight.
5. The core segment as recited in claim 4, wherein the stacked construction C, I or straight is formed by arranging the packets and groups of cut amorphous metal tapes.
6. The core segment as mentioned in claim 5, the segment having been annealed with a magnetic field in a continuous batch annealing furnace.
7. The core of the transformer as mentioned in claim 1, wherein the edges of each of the segments are coated with a joining material that protects the edges and offers the segment increased mechanical strength.
8. 8. The transformer core, as mentioned in claim 7, wherein the segments collectively form a core having a region of joints and the coating is applied to substantially the entire surface area of the core, excluding the region of the joints.
9. 9. The core segment as recited in claim 2, wherein each of the packages has a plurality of joint ends separately supported to be assembled in the finished transformer core.
10. 10. A method for constructing a transformer core comprises the steps of: a) forming a plurality of amorphous metal tape segments, each segment consisting of at least one packet of tapes and each pack comprising a plurality of groups of cut amorphous metal tapes. arranged in a lapel or splice pattern; and b) joining the segments together to form a transformer core.
11. The method for constructing a transformer core, as mentioned in claim 10, wherein the core has a joint region and the method further comprises the step of coating the edges of at least one of the segments with a material of Union that protects the edges and offers the segment increased mechanical strength.
12. The method for constructing a transformer core, as mentioned in claim 11, wherein the bonding material is applied to a substantial portion of the core.
13. The method for constructing a transformer core as mentioned in claim 12, wherein the bonding material is applied to practically the entire surface area of the core, excluding the region of the joints.
14. The core of the transformer as mentioned in claim 1, comprises two segments.
15. The core of the transformer as mentioned in claim 14 comprises two segments C and an even number of straight segments.
16. The core of the transformer as mentioned in claim 1, comprises four C segments arranged to form an external sheath-type core.
17. The core of the transformer as mentioned in claim 1, comprises two segments C and one segment I arranged to form an external sheath-type core.
18. 18. The core of the transformer as recited in claim 1, comprises two segments C, a segment I and an even number of straight segments arranged to form a three-leg core for a three-phase transformer.
19. 19. The core of the transformer as recited in claim 14, wherein the core has a joint region and the joint material is applied to the joint region to maintain contact between the segments therein.
20. 20. The core of the transformer as recited in claim 1, wherein the tapes have different widths arranged to provide a cruciform cross-section.
21. 21. The core of the transformer as mentioned in claim 1, the core being housed in a transformer filled with oil or dry type.
22. 22. The core of the transformer as mentioned in claim 21, wherein the transformer is a distribution transformer.
23. 23. The transformer core as recited in claim 22, wherein the transformer is an energy transformer. The core of the transformer as mentioned in claim 21, the core being used in a voltage conversion apparatus. The transformer core as mentioned in claim 1, wherein each of the tapes has a composition defined primarily by the formula: M7o-82 Y5-20 Z0-20 / the subscripts in percent of atoms, where "M" it is at least Fe, Ni or Co, "Y" is at least B, C or P, and "Z" is at least Si, Al or Ge; provided that: (i) up to 10 atomic percent of the "M" component can be substituted with at least one of the metallic species Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta or, and ( ii) up to 10 atomic percent of the components (Y + Z) can be substituted by at least one of the non-metallic species In, Sn, Sb and Pb. The core segment as mentioned in claim 2, wherein each of the tapes has a composition defined primarily by the formula M70-82 Y5-20 o-2? F the subscripts in atomic percent, where "M" is when less Fe, Ni or Co, "Y" is at least B, C or P, and "Z" is at least Si, Al or Ge; provided that: (i) up to 10 atomic percent of the "M" component can be substituted with at least one of the metallic species Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta or, and ( ii) up to 10 atomic percent of the components (Y + Z) can be substituted by at least one of the non-metallic species In, Sn, Sb and Pb. A method for constructing a transformer core as mentioned in claim 10, wherein each of the tapes has a composition defined primarily by the formula: M70-82 Y5-20 0-20? the subscripts in atomic percentage, where "M" is at least Fe, Ni or Co, "Y" is at least B, C or P, and "Z" is at least Si, Al or Ge; provided that: (i) up to 10 atomic percent of the "M" component can be substituted with at least one of the metallic species Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta or W, and (ii) up to 10 atomic percent of the components (Y + Z) can be substituted for at least one of the non-metallic species In, Sn, Sb and Pb.