AU2014100886A4 - Non-Conventional Core, Segmented, Toroid Transformer - Google Patents

Abstract

Abstract This patent describes a transformer comprising of a core housing filled with non conventional core material. The non-conventional core material can be a pure or a modified material that when taken as a whole has the ability to transmit magnetism, but is a poor in conduction or is a non-conductor. An example being insulated steel swarf. Due to the flexibility in selecting a core housing shape, transformers can be manufactured to any desired shape, size or segments with optimal efficiency. Furthermore, the use of segments in coil winding and core manufacturing will increase the overall manufacturing flexibilities. If required, the need for core housing can be eliminated with the use of a solid core, which can be manufactured by mixing insulated steel swarf with a hardening agent. Drawings - 12 - Fig.1----

Description

1 Title: Non-Conventional Core, Segmented, Toroid Transformer Technical Field: [0001] This invention relates to transformers and alternative methods for making transformer cores, specifically toroid transformers using non- conventional core materials. Background: [0002] Conventional toroid transformers are manufactured by winding a wire around the surface of the toroid by passing the end of the wire repeatedly through the central opening of the toroid. However, this process of winding wire around the core is time consuming and is a major hurdle in the manufacturing process. As a result, toroid transformers are often manufactured in small sizes. [0003] The larger transformers are made using conventional E I type cores. The manner in which these large E I transformers are constructed presents some drawbacks. Chiefly being that the magnetic field has to pass through edges from plate to plate, and that the magnetic field must go an unnecessarily long way and not along a magnetic orientation. [0004] Furthermore, E I transformers are constructed by stacking metal plates on top of each other with a thin layer of insulation between each sheet of metal. This insulation prevents the transfer of eddy current from plate to plate thus minimizing eddy currents. Despite the insulation there is still a path for eddy current to travel within individual plates. This challenge must also be considered when developing efficient transformers. [0005] These efficiency and manufacturing challenges can be overcome by utilizing a segmented toroid transformer with a non-conventional core, as presented in this invention.

2 Summary of Invention: [0006] This invention presents a different approach to toroid transformer construction. By using non-conventional core materials, core housing and segmented toroid, the challenges faced in the manufacturing process can be overcome and increased efficiency can be achieved. [0007] A non-conventional core material is any material that is a poor/non-conductor of electricity, but allows magnetic flux to travel through the core. Steel swarf-fine chips and or filings insulted with shellac-hereinafter called insulated swarf is used as the exemplary non-conventional core material for the purposes of this patent application. Insulation material similar to shellac can be used in most applications, while oil or grease can also be selected as an insulator depending on the circumstances of transformer application. [0008] Due to insulation the swarf pieces are electrically isolated from each other. Though individual pieces of non-conventional core material conduct electrical current, as a unit the tightly packed non-conventional core material no longer function as a good conductor. However, the insulated swarf pieces are still sensitive to magnetic field and are able to pass on magnetic flux between them. [0009] As the non-conventional core material is made up of small insulated swarf pieces or filings, the invention introduces the core housing as a hollow structure to contain this material. The core housing can be constructed to any desired shape using a heat resistant non-conductive material. [0010] Additionally, by using non-conventional core material to fill the core housing, allows the transformer core to be manufactured into any desired shape or size. For example this can be as: circular or arc shapes, segments, and intersections/joints. As the core housing can be made into any shape and then filled with non-conventional core material, makes it possible to create large transformer cores by manufacturing segments initially and then filling the segments with non-conventional core material. [0011] When the non-conventional core housing is filled with non-conventional core material, the flow of eddy current compared to that of a conventional transformer is 3 greatly reduced, while still creating a magnetic field with high permeability. As a result when current passes through the coil wound around the core housing optimum efficiency is achieved. [0012] The ability to select a circular cross sectional core over a rectangular cross sectional core is another advantage of this invention. In a rectangular cross sectional winding, the coil tension at right angle is different to the coil tension at the flat surface. Therefore, winding a coil on a rectangular type bobbin requires extra caution and attention. Selecting a circular cross sectional core housing eliminates this extra caution and attention (Fig. 8 and 8a). This therefore reduces the time and costs involved in transformer manufacturing. [0013] When comparing the circular/arc core to a right angle core as used in conventional transformers, the magnetic flux in the circular/arc core transformer travels along the shortest possible route without losing its strength, whilst maintaining a smooth flow, therefore resulting in an increased efficiency. [0014] There is the opportunity for manufactures to exclusively adapt the segmented aspect of this invention to manufacture a toroid transformer. This allows the flexibility of using an appropriate core material, such as the currently available laminated core (Fig. 9) or clusters of insulated steel wire (Fig. 10). Further, manufactures have the option of mixing a non-conventional core material with a hardening agent to create a solid core (Fig. 11). These core methods can be used with or without core housing. [0015] As mentioned previously, transformers can be manufactured to any desired shape (e.g. triangular (Fig. 6), inline (Fig. 7)) using circular or arc shapes, segments and intersection/joint core housing. This flexibility of the core housing allows manufactures to develop customized transformers that are best suited to size and space requirements. Brief Description of Drawing: [0016] The invention is now described with reference to the accompanying drawings, in which: 4 [0017] Fig.1 shows coil wound around a section of a core housing, filled with a non conventional core material (e.g. insulated swarf); [0018] Fig. 1 a shows the magnetic flux in a circular/arc core transformer; [0019] Fig. 2 shows an expanded view of a long loop eddy current path E I core transformers with laminated core; [0020] Fig. 2a shows the magnetic flux path of E I core transformers [0021] Fig. 3 shows nonmetallic core housing segment of a segmented toroid transformer; [0022] Fig. 3a shows nonmetallic bobbin of a segment of toroid transformer before coil winding; [0023] Fig. 4 shows coil wound halfway on a bobbin of a segmented toroid transformer; [0024] Fig. 4a shows completed coil wound bobbin; [0025] Fig. 4b shows a section of a core housing segment (Fig. 3) inserting into a coil wound bobbin (Fig. 4a); [0026] Fig. 4c shows complete segment of toroid transformer with the core housing segment embedded in the coil wound bobbin; [0027] Fig. 5 shows expanded view of segmented toroid transformer ready to assemble; [0028] Fig. 5a shows assembled segmented toroid transformer ready to be filled with non-conventional core material; [0029] Fig. 5b shows completed segmented toroid transformer with non-conventional core material; 5 [0030] Fig. 5c shows wire arrangement of a three-phase version of segmented toroid transformer; [0031] Fig. 5d shows wire arrangement of a signal-phase version of segmented toroid transformer; [0032] Fig. 6 shows an expanded view of triangular, interconnected and circular/arc core multiphase transformer made utilizing core housing with non-conventional core material; [0033] Fig. 7 shows an expanded view of inline, interconnected circular/arc core multiphase transformer made utilizing core housing with non-conventional core material; [0034] Fig. 8 shows winding of a coil to a square/rectangular sectional bobbin; [0035] Fig. 8a shows winding of a coil to a circular sectional bobbin; [0036] Fig. 9 shows an expanded view of toroid transformer segment in which the core is made using currently available conventional core material; [0037] Fig. 10 shows an expanded view of toroid transformer segment in which the core is made with clusters of insulated steel wire; [0038] Fig.1 1 shows an expanded view of segment of a toroid transformer in which the core is made by mixing a non-conventional core material with a hardening agent to create a solid core. [0039] Additionally, in these figures individual items are labeled as follows: [0040] Item 12 shows the coil (conductor); [0041] Item 13 shows the insulated swarf/non-conventional core material; [0042] Item 14 shows the core housing wall; 6 [0043] Item 15 shows the magnetic path; [0044] Item 16 shows the laminated core; [0045] Item 17 shows the long loop path of the eddy current; [0046] Item 18 shows a toroid core housing segment; [0047] Item 19 shows the tail end of a core housing segment; [0048] Item 20 shows the fixed jaw end of a core housing segment; [0049] Item 21 shows the removable jaw of a core housing segment; [0050] Item 22 shows the tail port of a core housing segment; [0051] Item 23 shows the main port of a core housing segment; [0052] Item 24 shows the main port cover of a core housing segment; [0053] Items 25 shows the bobbin; [0054] Item 26 shows coil wound bobbin; [0055] Item 27 shows a toroid transformer segment with inserted toroid core housing segment; [0056] Item 28 shows a toroid core segment made with conventional core material; [0057] Item 29 shows a toroid core segment made with clusters of insulated steel wire; [0058] Item 30 shows the toroid core segment made from non-conventional core material mixed with hardening agent to create a solid piece.

7 Description of Embodiments: [0059] It should be noted that in the detailed description that follows, identical components have the same reference numerals, regardless of whether they be shown in different embodiments of the present invention. It should also be noted that Fig. 3 to 5d describes a typical example of a segmented toroid construction. [0060] Shown in Fig. 1 is a section of a core housing, generally designated as 14, containing the tightly packed non-conventional core material (insulated swarf), which is designated as 13. The current flow in item 12 consisting of the coil wound around the core housing, generates a magnetic field, which is transferable between the insulated swarf pieces. However, the eddy current that is developed due to the aforementioned current flow is not transferable between the insulated swarf pieces. This has the advantage of reducing eddy current whilst maximising the magnetic field. [0061] Fig. 1 a shows in detail the path of the magnetic flux, item 15, which travels along its oriented path. In a toroid transformer the magnetic flux flows in a circular path along the orientation of the toroid core. This is more efficient in comparison to a conventional E I transformer, where the flux flows from 'edge to edge' of the core thus lowering its efficiency. Figure 2a shows the magnetic flux behaviour in a more commonly utilised E I core transformers, when the current flows in item 12, the coil. In these transformers the steel plates are stacked on top of each other between layers of insulation, as depicted by item 16. Due to the presence of insulation barriers between the steel plates there is no flow of eddy current between plates. However, as the cross section of a laminated plate is much larger than that of an individual piece of insulated swarf, there is ample room for eddy current to travel inside these single plates, as illustrated by item 17. [0062] The following description outlines the process involved in developing a segmented toroid transformer utilizing a non-conventional core material. The toroid is divided into three identical segments. Each of these segments consists of: a bobbin, depicted by item 25, and a core housing, depicted by item 18. Both of the above mentioned is constructed utilizing heat resistant and non-metallic materials. The core housing is appropriately sized enabling its insertion into the bobbin.

8 [0063] Fig. 3 shows an expanded view of the segment of core housing. This comprises of core housing (item18), removable jaw (item 21), a main port (item 23), and main port cover (item 24). The two ends of the core housing segment are different, named as tail end (item 19) and fixed jaw end (item 20). The fixed jaw is also used for connecting the mounting bracket. [0064] When assembling the toroid core housing, the tail port (item 22) aligns with the main port in the next core housing segment's removable jaw (Fig. 5 and 5a). This process repeats for all three segments, until the circular shape in complete. The outer body of the core housing is appropriately sized in order to enable smooth insertion in to the bobbin until it reaches the edge of the fixed jaw. [0065] Fig. 4 shows the manner in which a wire is wound around a segment of a bobbin to construct a coil wound bobbin. A bobbin completed in such manner is shown in Fig. 4a. After completion of such a wound segment, typical procedures involved in transformer coil treatment can be applied (i.e. shellacking and baking). [0066] The core housing segment is then inserted in to the coil wound bobbin (Fig. 4b and 4c). Fig. 5 shows three core housing segments inside coil wound bobbins ready to be assembled in the shape of a toroid. This is done by placing the tail end of one segment to the fixed jaw end of the next segment. Thereafter, all three bobbins are locked in their positions using removable jaws. One side of the bobbin is locked into position by the fixed jaw of its own core housing, while the other side is stopped by the jaw of next core housing (see Fig. 5 and 5a). [0067] After assembling the three toroid segments, but prior to locking them with the removable jaws (Fig. 5a), insulated swarf is fed in to the core housing through the tail ports. When the required amount of insulated swarf is fed in to the core housing initial filling is completed and the removable jaws can be fitted. If the insulated swarf is slurry, the manufacturer may use the main port to remove the trapped air. The main port may also be used to compact the insulated swarf, if necessary. Finally, the main port cover is placed over the main port to form the segmented toroid transformer (Fig. 5b). [0068] Each segment of the toroid transformer is identical and spans 120 degrees of the toroid. Whether it be a single-phase transformer or a three phase transformer, 9 same segments can be utilized. Since, the segments are identical in this invention, it is cost effective, straightforward and simple to replicate in mass production. [0069] If we construct a three-phase transformer each phase can be completed within a single segment. All ends of the primary and secondary can be built in each segment (Fig. 5c). If it is single-phase toroid transformer, the number of total turns of primary and secondary coils can be equally divided between segments. After assembling the segments in to a toroid, the coil ends can be series connected as shown in Fig. 5d. [0070] In this invention, due to the flexibility in the manufacturing of the core housing, coil winding and assembling, the manufactures can design and develop customized transformers of any shape that is best suited to their requirements. As an example, triangular, inline or transformers of any other desired shape can be manufactured to accommodate circular or arc shapes, segments and intersection/joint core housing. [0071] However, if the manufacture wish to use the other types of core material (e.g. laminated conventional core, insulated wire, solid piece of non-conventional core) instead of the non-conventional core material, it is possible to manufacture conventional core segmented toroid transformers with or without core housing. In this instance, the bobbin is coil wound in the same way as described in paragraph 0065. The aforementioned core types can then be inserted in to the core housing or the bobbin (Figs. 9,10,11). If core housing is not used, joining of conventional core material inserted bobbin can be any other joining method preferred by the manufacturer.

Claims (5)

1. A segmented toroid transformer with a non-conventional core material (refer to paragraph 0007) and whereby this non-conventional core material is used to fill a core housing (refer to paragraph 0009). For examples see Figs. 3 to 5d.

2. A segmented transformer of any other shape (in addition to the toroid shape mentioned in claim 1) comprising of coil run segments of core housing (refer to paragraph 0009) filled with non-conventional core material (refer to paragraph 0007). For example, transformers comprising of circular or arc cores with joints and intersections manufactured using non-conventional core material and core housing (refer to paragraph 0010 and Fig. 6 - 7).

3. A segmented toroid transformer in which the core, manufactured with or without core housing, is made with a conventional core material, clusters of insulated steel wires or a non-conventional core material (i.e. adding a hardening agent to create a solid core). Figs. 9, 10 and 11, and paragraph 0014 are provided as examples of each of these respective methods of transformer construction.

4. A transformer, segmented or otherwise, that uses core housing (refer to paragraph 0009) and non-conventional core material (refer to paragraph 0007). For an example, an E I shape transformer core developed using aforementioned core housing and core material.

5. Transformers constructed according to claims 1 - 4 facilitates the use of coil wound bobbins with circular cross sections. This invention covers bobbins with circular cross-sections. This invention covers transformers with circular cross sectional bobbins.