Tap changeover stand unit and tap changeover stand

Abstract

To provide a tap changeover stand unit and a tap changeover stand capable of improving the workability of installation.SOLUTION: A tap changeover unit 100 used in a transformer includes a plurality of tap changeover units 1A, 1B, 1C attached to an iron core fastening fixture 50. One end portion of each of a plurality of tap changeover stands 1A, 1B, 1C is provided at a stand portion 2A, 2B, 2C having a plurality of tap terminals 3A, 3B, 3C, and the other end portion thereof includes two attachment portions 4A, 4B, 4C to be fixed to the iron core fastening fixture 50. At least one attachment portion 4A, 4B, 4C is fixed to the iron core fastening fixture 50 together with the other attachment portions 4A, 4B, 4C of the tap changeover stand 1A, 1B, 1C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tap changing base unit and a tap changing base. [Background technology]

[0002] Conventionally, an insulating tap changer has been used to change taps in a transformer (see Patent Documents 1 and 2). Such an insulating tap changer is attached to a core fastener that fixes a wound core having a coil to a container in which the wound core is housed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-112060 [Patent Document 2] Japanese Patent Application Publication No. 6-112061 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in the case of a three-phase tap changer, it is necessary to attach three tap changers to one side of the core fastening fixture. However, since the core fastening fixture is narrow, this work is time-consuming. Such problems are not sufficiently considered in Patent Documents 1 and 2, and cannot be solved.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a tap changer unit and a tap changer that can improve the ease of installation. [Means for solving the problem]

[0006] The tap changing table unit of the present invention is a tap changing table unit for use in a transformer, in which a plurality of tap changing tables are attached to a plate member, each of the plurality of tap changing tables having one end provided on a base portion having a plurality of tap terminals and two fixing legs whose other end is fixed to the plate member, and at least one of the fixing legs is fixed to the plate member together with the fixing legs of the other tap changing tables.

[0007] The tap changer base of the present invention is a tap changer base used in a changer base unit for a transformer in which a plurality of tap changer bases are attached to a plate member, and has one end provided on a base portion having a plurality of tap terminals and two fixed legs whose other end is fixed to the plate member, and the length of one of the two fixed legs is shorter than the length of the other fixed leg. Effect of the Invention

[0008] According to the present invention, it is possible to provide a tap changer unit and a tap changer base that can improve the ease of installation. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of a tap changing base unit including a tap changing base according to the first embodiment. [Diagram 2] 1A and 1B are a front view and a bottom view of a tap changing table of a tap changing table unit of embodiment 1. [Diagram 3] 4 is a bottom view of another tap changing table of the tap changing table unit according to the first embodiment. FIG. [Figure 4] FIG. 2 is a conceptual diagram showing a state in which three tap changer blocks are attached to an iron core fastening fixture. [Diagram 5] 5 is a cross-sectional view taken along line VV in FIG. 4. [Figure 6] 11 is a cross-sectional view showing a state in which a mounting portion of a tap changing stand and a mounting portion of another tap changing stand are fastened together in a tap changing stand unit according to a second embodiment. FIG. [Figure 7]13 is a cross-sectional view showing a state in which a mounting portion of a tap changing stand and a mounting portion of another tap changing stand are fastened together in a tap changing stand unit according to a third embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the present invention will be described with reference to the drawings showing an embodiment thereof.

[0011] (Embodiment 1) Fig. 1 is a perspective view of a tap changing table unit 100 including a tap changing table according to embodiment 1. The tap changing table unit 100 is used, for example, in an oil-immersed transformer. The tap changing table unit 100 shown in Fig. 1 is a three-phase tap changing table unit, and includes three tap changing tables 1A, 1B, and 1C, and a core fastener 50 (plate member) that fastens a wound core having a coil to a container (not shown) in which the wound core is housed.

[0012] The core fastening bracket 50 is made of metal and has the shape of a flat case with one side open. The core fastening bracket 50 has a rectangular flat plate portion 51, and side walls extending perpendicularly are connected to each of the four sides of the flat plate portion 51. In the core fastening bracket 50, the opposing side walls have the same dimensions, and the side walls associated with the long sides have a larger dimension in the thickness direction of the flat plate portion 51 than the side walls associated with the short sides.

[0013] Three tap changer tables 1A, 1B, and 1C are attached to the outer surface of the flat plate portion 51. The three tap changer tables 1A, 1B, and 1C are arranged in a row in the longitudinal direction of the flat plate portion 51 in this order. Of the three tap changer tables 1A, 1B, and 1C, the tap changer tables 1B and 1C have the same shape, and the tap changer table 1A has a shape different from the tap changer tables 1B and 1C. For the sake of convenience, only the tap changer table 1B will be described below, and the description of the tap changer table 1C will be omitted.

[0014] Fig. 2 is a front view and a bottom view of the tap changing table 1B of the tap changing table unit 100 according to embodiment 1. Fig. 2A is a front view of the tap changing table 1B, and Fig. 2B is a bottom view.

[0015] The tap changer base 1B includes a base portion 2B, a plurality of tap terminals 3B, and mounting portions 4B and 5B (fixing legs). Fig. 2 shows a case where a pair of tap terminals 3B is connected by a connecting piece P. The connecting piece P is fixed to the pair of tap terminals 3B by a nut.

[0016] The base portion 2B is made of a thermoplastic resin having heat resistance, oil resistance, and electrical insulation properties. The thermoplastic resin is, for example, a polyamide resin, a PPS (polyphenylene sulfide) resin, etc. The thermoplastic resin may be, for example, a thermoplastic engineering plastic (engineering plastic) or a super engineering plastic, and may contain a reinforcing agent such as glass fiber or an inorganic filler.

[0017] The base portion 2B has a semicircular portion and a semi-elliptical portion having a smaller diameter than the semicircular portion, and the semicircular portion and the semi-elliptical portion are disposed in the same plane. The semi-elliptical portion is connected to the center of the linear edge portion of the semicircular portion. The base portion 2B is provided with reinforcing ribs 21B along the edge. The reinforcing ribs 21B are provided to protrude in the thickness direction of the base portion 2B.

[0018] The semicircular portion of the base 2B is provided with mounting portions 4B, 5B. The mounting portions 4B, 5B are connected to both ends of the linear edge of the semicircular portion, respectively. The mounting portions 4B, 5B fix the tap changer base 1B (base 2B) to the core fastening fixture 50.

[0019] The tap terminal 3B is made of, for example, brass, and is a so-called insert metal fitting. The semicircular portion and the semi-elliptical portion of the base portion 2B are provided with a plurality of bosses 22B penetrating the base portion 2B in the thickness direction. Each boss 22B is cylindrical, with both ends of the boss 22B protruding from the corresponding two main surfaces of the base portion 2B, and a tap terminal 3B is provided on each boss 22B. A tap wire drawn from a tap of a transformer or the like is connected to each tap terminal 3B, or a connection piece that electrically connects a plurality of tap wires is fixed to each tap terminal 3B.

[0020] The tap terminal 3B has a male threaded portion 31B, a female threaded portion 32B, and a cap nut 33B. More specifically, the cap nut 33B, which is cylindrical and has a bottom, is fitted into the boss 22B, and a female threaded portion 32B is formed on the cap nut 33B. Therefore, in the tap terminal 3B, the male threaded portion 31B protrudes from one main surface of the base portion 2B, and the female threaded portion 32B opens from the other main surface opposite to the one main surface. That is, the tap terminal 3B penetrates the base portion 2B in the thickness direction.

[0021] The attachment portions 4B and 5B are substantially rectangular, extend in a direction away from the other main surface of the base portion 2B, and have ends bent in parallel to the base portion 2B.

[0022] The mounting portion 4B has a vertical portion 41B that extends along the thickness direction of the base portion 2B, i.e., perpendicular to the main surface of the base portion 2B, and a parallel portion 42B that is parallel to the base portion 2B. One end of the vertical portion 41B is connected to the base portion 2B, and the parallel portion 42B is connected to the other end of the vertical portion 41B. The convex corner at the tip of the parallel portion 42B is R-chamfered.

[0023] A reinforcing rib 44B is provided along the edge of the mounting portion 4B. The reinforcing rib 44B protrudes in the thickness direction of the mounting portion 4B and is connected to the reinforcing rib 21B of the base portion 2B. A boss 43B is provided in the center of the parallel portion 42B and is used when attaching the tap changer 1B to the iron core fastening fixture 50. The boss 43B penetrates the parallel portion 42B in the thickness direction. The boss 43B has a cylindrical shape, and both ends of the boss 43B protrude from the corresponding two main surfaces of the parallel portion 42B. An insert nut 432B is fitted into a through hole 431B of the boss 43B (see FIG. 5). A screw hole 433B is formed in the insert nut 432B (see FIG. 5). The tap changer 1B is fixed by inserting a bolt (not shown) into the screw hole 433B of the insert nut 432B and screwing it to the iron core fastening fixture 50.

[0024] The mounting portion 5B has a vertical portion 51B that extends along the thickness direction of the base portion 2B, i.e., perpendicular to the main surface of the base portion 2B, and a parallel portion 52B that is parallel to the base portion 2B. One end of the vertical portion 51B is connected to the base portion 2B, and the parallel portion 52B is connected to the other end of the vertical portion 51B. The convex corner at the tip of the parallel portion 52B is R-chamfered.

[0025] The length of the vertical portion 51B of the mounting portion 5B is shorter than the length of the vertical portion 41B of the mounting portion 4B (see FIG. 2B). More specifically, the length of the vertical portion 51B is shorter than the length of the vertical portion 41B by the thickness of the parallel portion 42B.

[0026] A reinforcing rib 54B is provided along the edge of the mounting portion 5B. The reinforcing rib 54B protrudes in the thickness direction of the mounting portion 5B and is connected to the reinforcing rib 21B of the base portion 2B. A boss 53B is provided in the center of the parallel portion 52B and is used when attaching the tap changer 1B to the core fastening fixture 50. The boss 53B penetrates the parallel portion 52B in the thickness direction. An insert nut (not shown) is fitted into the through hole of the boss 53B. The shapes of the boss 53B and the insert nut are the same as those of the boss 43B and the insert nut 432B described above, and detailed description will be omitted. The tap changer 1B is fixed by inserting a bolt (not shown) into the screw hole of the insert nut and screwing it to the core fastening fixture 50.

[0027] The mounting portions 4B and 5B are made of a thermoplastic resin having heat resistance, oil resistance, and electrical insulation properties, that is, the mounting portions 4B and 5B are made of a thermoplastic resin such as polyamide resin, PPS resin, etc., similar to the base portion 2B.

[0028] In the tap changer base 1B according to the embodiment 1, the base portion 2B and the mounting portions 4B and 5B are integrally molded. The base portion 2B and the mounting portions 4B and 5B are both made of a thermoplastic resin and are manufactured by, for example, injection molding the thermoplastic resin.

[0029] FIG. 3 is a bottom view of another tap changing stand 1A of the tap changing stand unit 100 according to the first embodiment. The tap changer base 1A, like the tap changer base 1B, includes a base portion 2A, a plurality of tap terminals 3A, and an attachment portion 4A (fixing leg portion). Fig. 3 shows a case where a pair of tap terminals 3A are connected by a connection piece P. The connection piece P is fixed to the pair of tap terminals 3A by a nut.

[0030] The base portion 2A and the tap terminal 3A are the same as the base portion 2B and the tap terminal 3B of the tap changing base 1B described above, and detailed description thereof will be omitted.

[0031] The semicircular portion of the base 2A is provided with a mounting portion 4A. The mounting portions 4A are connected to both ends of the linear edge of the semicircular portion. Each mounting portion 4A has the same shape and fixes the tap changer base 1A (base 2A) to the core fastening fixture 50.

[0032] Each attachment portion 4A is substantially rectangular, extends in a direction away from the other main surface of the base portion 2A, and has an end bent in parallel with the base portion 2A. The mounting portion 4A has a vertical portion 41A that extends along the thickness direction of the base portion 2A, i.e., perpendicular to the main surface of the base portion 2A, and a parallel portion 42A that is parallel to the base portion 2A. One end of the vertical portion 41A is connected to the base portion 2A, and the parallel portion 42A is connected to the other end of the vertical portion 41A. The convex corner at the tip of the parallel portion 42A is R-chamfered.

[0033] As described above, in the tap changer base 1A, the length of the vertical portions 41A of both mounting portions 4A is the same, and the length of the vertical portions 41A of each mounting portion 4A is the same as the length of the vertical portion 41B of the mounting portion 4B of the tap changer base 1B.

[0034] The mounting portion 4A is provided with reinforcing ribs along the edge. A boss 43A is provided in the center of the parallel portion 42A and is used when attaching the tap changer 1A to the core fastening fixture 50. The boss 43A penetrates the parallel portion 42A in the thickness direction. An insert nut (not shown) is fitted into the through hole of the boss 43A. The shapes of the boss 43A and the insert nut are the same as those of the boss 43B and the insert nut 432B of the tap changer 1B described above, and detailed description will be omitted. The tap changer 1A is fixed by inserting a bolt (not shown) into the screw hole of the insert nut and screwing it to the core fastening fixture 50.

[0035] The mounting portion 4A is made of a thermoplastic resin having heat resistance, oil resistance, and electrical insulation properties. That is, like the base portion 2A, the mounting portion 4A is made of a thermoplastic resin such as polyamide resin or PPS resin. The base portion 2A and the mounting portion 4A are integrally molded. The base portion 2A and the mounting portion 4A are manufactured, for example, by injection molding a thermoplastic resin.

[0036] Fig. 4 is a diagram conceptually showing a state in which three tap changer bases 1A, 1B, 1C are attached to an iron core fastening fixture 50. For convenience, in Fig. 4, the iron core fastening fixture 50 is shown by a two-dot chain line.

[0037] As described above, the tap changing tables 1A, 1B, and 1C are connected in this order, that is, the tap changing table 1B is connected to the tap changing table 1A, and the tap changing table 1C is connected to the tap changing table 1B. More specifically, of the two mounting portions 4A of the tap changing table 1A, the mounting portion 4A closer to the tap changing table 1B (hereinafter referred to as the mounting portion 4A closer to 1B) is connected to the mounting portion 5B of the tap changing table 1B, and the mounting portion 5C of the tap changing table 1C is connected to the mounting portion 4B of the tap changing table 1B.

[0038] With the parallel portion 52B of the mounting portion 5B of the tap changer table 1B, which is shorter, placed on the parallel portion 42A of the mounting portion 4A closer to 1B of the tap changer table 1A, the parallel portion 42A (boss 43A) of the mounting portion 4A closer to 1B and the parallel portion 52B (boss 53B) of the mounting portion 5B are fastened together. Also, with the parallel portion 52C of the mounting portion 5C of the tap changer table 1C, which is shorter, placed on the parallel portion 42B of the mounting portion 4B of the tap changer table 1B, the parallel portion 42B (boss 43B) of the mounting portion 4B and the parallel portion 52C (boss 53C) of the mounting portion 5C are fastened together.

[0039] Fig. 5 is a cross-sectional view taken along line VV in Fig. 4. For ease of explanation, the bolts and the core fastening metal fittings 50 are omitted from Fig. 5. Fig. 5 shows a state in which the parallel portion 52C of the mounting portion 5C is placed on the parallel portion 42B of the mounting portion 4B, as described above.

[0040] An insert nut 432B (threaded hole 433B) provided in the through hole 431B of the boss 43B and an insert nut 532C (threaded hole 533C) provided in the through hole 531C of the boss 53C are arranged on the same axis. The insert nut 432B of the boss 43B is continuous with the insert nut 532C of the boss 53C in the overlapping direction. The threaded hole 433B of the insert nut 432B of the boss 43B and the threaded hole 533C of the insert nut 532C of the boss 53C have the same inner diameter.

[0041] In this state, the worker can insert a bolt from parallel portion 52C (boss 53C) through screw hole 533C of insert nut 532C and screw hole 433B of insert nut 432B, and screw it into core fastening bracket 50, thereby fastening parallel portion 52C and parallel portion 42B together to core fastening bracket 50.

[0042] The above describes the state in which the parallel portion 42B of the mounting portion 4B of the tap changer table 1B and the parallel portion 52C of the mounting portion 5C of the tap changer table 1C are fastened together, but the same applies to the case in which the parallel portion 42A of the mounting portion 4A of the tap changer table 1A and the parallel portion 52B of the mounting portion 5B of the tap changer table 1B are fastened together. The following description will be given with reference to Figure 5 (see symbols in parentheses).

[0043] An insert nut 432A (screw hole 433A) provided in the through hole 431A of the boss 43A and an insert nut 532B (screw hole 533B) provided in the through hole 531B of the boss 53B are arranged on the same axis. The insert nut 432A of the boss 43A is continuous with the insert nut 532B of the boss 53B in the overlapping direction. The screw hole 433A of the insert nut 432A of the boss 43A and the screw hole 533B of the insert nut 532B of the boss 53B have the same inner diameter.

[0044] In this state, the worker can insert a bolt from parallel portion 52B (boss 53B) through screw hole 533B of insert nut 532B and screw hole 433A of insert nut 432A, and screw it into core fastening bracket 50, thereby fastening parallel portion 52B and parallel portion 42A together to core fastening bracket 50.

[0045] As described above, in the tap changing table unit 100 of embodiment 1, the parallel portion 42A of the mounting portion 4A near the 1B of the tap changing table 1A and the parallel portion 52B of the mounting portion 5B of the tap changing table 1B are fastened together, and the parallel portion 42B of the mounting portion 4B of the tap changing table 1B and the parallel portion 52C of the mounting portion 5C of the tap changing table 1C are fastened together. Therefore, the number of steps required to attach the tap changer bases 1A, 1B, 1C to the core fastening fixture 50 can be reduced, improving workability.

[0046] As described above, in the tap changer unit 100 according to the first embodiment, the parallel portion 52B of the mounting portion 5B of the tap changer table 1B is superimposed on the parallel portion 42A of the mounting portion 4A closer to the 1B of the tap changer table 1A, and the parallel portion 52C of the mounting portion 5C of the tap changer table 1C is superimposed on the parallel portion 42B of the mounting portion 4B of the tap changer table 1B. Therefore, the tap changer tables 1A, 1B, 1C can be collectively mounted on the narrow flat plate portion 51, and the tap changer table unit 100 can be made compact.

[0047] Furthermore, in the tap changer table unit 100 according to the first embodiment, when the tap changer table 1A is fastened together as described above, the parallel portion 52B of the mounting portion 5B of the tap changer table 1B, which has a shorter length, is placed on the parallel portion 42A of the mounting portion 4A closer to the tap changer table 1B, and the parallel portion 52C of the mounting portion 5C of the tap changer table 1C, which has a shorter length, is placed on the parallel portion 42B of the mounting portion 4B of the tap changer table 1B. Therefore, after the mounting is completed, the base portion 2A of the tap changer table 1A, the base portion 2B of the tap changer table 1B, and the base portion 2C of the tap changer table 1C are parallel to the iron core fastening fixture 50 (flat plate portion 51), so that wiring between the base portions 2A, 2B, and 2C and the iron core fastening fixture 50 (flat plate portion 51) is facilitated.

[0048] In the above, the case where the base portion 2A and the mounting portion 4A are integrally molded, the base portion 2B and the mounting portions 4B and 5B are integrally molded, and the base portion 2C and the mounting portions 4C and 5C are integrally molded has been described as an example, but the present invention is not limited to this. It goes without saying that the effects of the present invention can be achieved even in a configuration where the base portion 2A and the mounting portion 4A are separate members, the base portion 2B and the mounting portions 4B and 5B are separate members, and the base portion 2C and the mounting portions 4C and 5C are separate members and assembled by screwing or the like.

[0049] Furthermore, in the above description, the length of the vertical portions 51B, 51C of the mounting portions 5B, 5C of the tap changer tables 1B, 1C is shorter than the length of the vertical portion 41A of the mounting portion 4A of the tap changer table 1A, and the length of the vertical portions 41B, 41C of the mounting portions 4B, 4C of the tap changer tables 1B, 1C is equal to the length of the vertical portion 41A of the mounting portion 4A of the tap changer table 1A (see FIG. 4). However, the present invention is not limited to this.

[0050] For example, the length of the vertical portion 51C of the mounting portion 5C in the tap changer table 1C may be the same as the length of the vertical portion 41C of the mounting portion 4C, and the length of the vertical portion 41B of the mounting portion 4B in the tap changer table 1B may be the same as the length of the vertical portion 51B of the mounting portion 5B. In this case, the lengths of the vertical portions 41A, 51C, and 41C of the tap changer table 1A and 1C are the same, and the length of both vertical portions 51B and 41B of the tap changer table 1B is shorter than the vertical portions 41A, 51C, and 41C. Therefore, the two parallel portions 52B and 42B of the tap changer table 1B are fastened together while placed on the parallel portions 42A and 52C of the tap changer tables 1A and 1C.

[0051] (Embodiment 2) Fig. 6 is a cross-sectional view showing a state in which the mounting portion 4B of the tap changing base 1B and the mounting portion 5C of another tap changing base 1C are fastened together in the tap changing base unit 100 according to embodiment 2. For ease of explanation, the bolts and the core fastening fixture 50 are omitted from Fig. 6.

[0052] 6, an insert nut 432B is provided in the through hole 431B of the boss 43B of the tap changing table 1B, and an insert nut 532C is provided in the through hole 531C of the boss 53C of the tap changing table 1C. The insert nut 432B of the boss 43B is continuous with the insert nut 532C of the boss 53C in the overlapping direction.

[0053] Further, the diameter of the screw hole 433B of the insert nut 432B of the boss 43B is smaller than the diameter of the screw hole 533C of the insert nut 532C of the boss 53C. The insert nut 432B and the insert nut 532C are arranged coaxially.

[0054] In this state, the tap changing table unit 100 of embodiment 2 can be fastened together by an operator by inserting a bolt from parallel portion 52C (boss 53C) through screw hole 533C of insert nut 532C and screw hole 433B of insert nut 432B, and screwing it into core fastening bracket 50, thereby fastening parallel portion 52C and parallel portion 42B together to core fastening bracket 50.

[0055] Fig. 6 only shows the state in which the mounting portion 4B of the tap changing table 1B and the mounting portion 5C of the tap changing table 1C are fastened together, but in the tap changing table unit 100 according to embodiment 2, the mounting portion 4A of the tap changing table 1A nearer to 1B and the mounting portion 5B of the tap changing table 1B are also fastened together, as in embodiment 1. The following description will be given with reference to Fig. 6 (see the symbols in parentheses).

[0056] With the parallel portion 52B of the mounting portion 5B of the tap changer base 1B, which is shorter, superimposed on the parallel portion 42A of the mounting portion 4A closer to 1B of the tap changer base 1A, the parallel portion 42A of the mounting portion 4A closer to 1B and the parallel portion 52B of the mounting portion 5B are fastened together, and with the parallel portion 52C of the mounting portion 5C of the tap changer base 1C, which is shorter, superimposed on the parallel portion 42B of the mounting portion 4B of the tap changer base 1B, the parallel portion 42B of the mounting portion 4B and the parallel portion 52C of the mounting portion 5C are fastened together (see Figure 4).

[0057] As described above, in the tap changing table unit 100 according to the second embodiment, the diameter of the screw hole 533C of the insert nut 532C of the tap changing table 1C (boss 53C), into which the bolt begins to be inserted when the tap changing tables 1C and 1B (boss 43B) are tightened together, is larger than the screw hole 433B of the insert nut 432B of the tap changing table 1B (boss 43B), so that the bolt can be easily passed through the screw hole 533C of the insert nut 532C and the screw hole 433B of the insert nut 432B. Therefore, the workability when attaching the tap changing tables 1A, 1B, and 1C to the core tightening fixture 50 can be improved.

[0058] The same parts as those in the first embodiment are given the same reference numerals and detailed description thereof will be omitted.

[0059] (Embodiment 3) Fig. 7 is a cross-sectional view showing a state in which the mounting portion 4B of the tap changing base 1B and the mounting portion 5C of another tap changing base 1C are fastened together in the tap changing base unit 100 according to embodiment 3. For ease of explanation, the bolts and the core fastening fixture 50 are omitted from Fig. 7.

[0060] 7, an insert nut 432B is provided in the through hole 431B of the boss 43B of the tap changing table 1B, and an insert nut 532C is provided in the through hole 531C of the boss 53C of the tap changing table 1C. The insert nut 432B of the boss 43B is adjacent to the insert nut 532C of the boss 53C in the overlapping direction.

[0061] In the overlapping direction, the dimension of the insert nut 532C of the boss 53C is shorter than the dimension of the through hole 531C of the boss 53C. The upper end of the insert nut 532C is aligned with the upper end of the boss 53C, and the insert nut 532C is not present inside the lower end of the boss 53C, which is hollow.

[0062] On the other hand, in the overlapping direction, the dimension of the insert nut 432B of the boss 43B is longer than the dimension of the through hole 431B of the boss 43B. The lower end of the insert nut 432B is aligned with the lower end of the boss 43B, and the upper end of the insert nut 432B protrudes from the upper end of the boss 43B.

[0063] The diameter of the screw hole 433B of the insert nut 432B is the same as the diameter of the screw hole 533C of the insert nut 532C, and the diameter of the through hole 431B of the boss 43B is the same as the diameter of the through hole 531C of the boss 53C. The insert nut 432B and the insert nut 532C are arranged on the same axis.

[0064] In the tap changing stand unit 100 according to the third embodiment, when the worker tightens the mounting portion 4B of the tap changing stand 1B and the mounting portion 5C of the tap changing stand 1C together, as described above, the parallel portion 52C of the mounting portion 5C of the tap changing stand 1C is placed on the parallel portion 42B of the mounting portion 4B of the tap changing stand 1B, and then the protruding portion (upper end) of the insert nut 432B is fitted into the cavity at the lower end of the through hole 531C. This determines the positions of the insert nut 532C (threaded hole 533C) and the insert nut 432B (threaded hole 433B).

[0065] In this state, the worker can insert a bolt from parallel portion 52C (boss 53C) through screw hole 533C of insert nut 532C and screw hole 433B of insert nut 432B, and screw it into core fastening bracket 50, thereby fastening parallel portion 52C and parallel portion 42B together to core fastening bracket 50.

[0066] Figure 7 only shows the state in which the mounting portion 4B of the tap changing table 1B and the mounting portion 5C of the tap changing table 1C are fastened together, but in the tap changing table unit 100 of embodiment 3, as in embodiment 1, the mounting portion 4A near the 1B of the tap changing table 1A and the mounting portion 5B of the tap changing table 1B are also fastened together.

[0067] In other words, with the parallel portion 52B of the mounting portion 5B of the tap changer base 1B, which is shorter, superimposed on the parallel portion 42A of the mounting portion 4A closer to 1B of the tap changer base 1A, the parallel portion 42A of the mounting portion 4A closer to 1B and the parallel portion 52B of the mounting portion 5B are fastened together, and with the parallel portion 52C of the mounting portion 5C of the tap changer base 1C, which is shorter, superimposed on the parallel portion 42B of the mounting portion 4B of the tap changer base 1B, the parallel portion 42B of the mounting portion 4B and the parallel portion 52C of the mounting portion 5C are fastened together (see Figure 4).

[0068] As described above, in the tap changing table unit 100 according to the third embodiment, the upper end (engagement protrusion) of the insert nut 432B is fitted into and engaged with the cavity of the lower end (engaged portion) of the through hole 531C, thereby determining the positions of the insert nut 532C (screw hole 533C) and the insert nut 432B (screw hole 433B). Therefore, in the overlapping direction, the position of the screw hole 533C of the tap changing table 1C and the position of the screw hole 433B of the tap changing table 1B can be aligned and maintained. Therefore, when tightening together, it becomes easier to pass a bolt through the screw hole 533C of the tap changing table 1C (insert nut 532C) and the screw hole 433B of the tap changing table 1B (insert nut 432B), and the workability when attaching the tap changing tables 1A, 1B, and 1C to the core tightening fixture 50 can be improved.

[0069] The same parts as those in the first embodiment are given the same reference numerals and detailed description thereof will be omitted.

[0070] The technical features (constituent elements) described in the first to third embodiments can be combined with each other, and by combining them, new technical features can be arrived at. The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the scope and meaning equivalent to the claims.

[0071] The matters described in each embodiment can be combined with each other. In addition, the independent claims and dependent claims described in the claims can be combined with each other in any and all combinations regardless of the citation format. Furthermore, the claims use a format in which a claim cites two or more other claims (multiple claim format), but this is not limited to this. The claims may also be written in a format in which a multiple claim cites at least one other multiple claim (multi-multi claim). [Explanation of symbols]

[0072] 1A: tap changer table (tap changer table at one end), 1B: tap changer table (remaining tap changer table), 1C: tap changer table (tap changer table at the other end), 2A, 2B, 2C: base part, 3A, 3B, 3C: tap terminal, 4A, 4B, 4C: mounting part (other fixed leg part), 5B, 5C: mounting part (one fixed leg part), 42A, 42B, 42C: parallel part (other end part), 50: iron core fastening bracket (plate member), 51: flat plate part, 52B, 52C: parallel part (other end part), 53C: boss (engaged part), 100: tap changer table unit, 432B: insert nut (engagement protrusion), 433B, 433A: screw hole (first through hole), 533C, 533B: screw hole (second through hole)

Claims

1. A tap changer unit for use in a transformer, the tap changer unit including a plurality of tap changers attached to a plate member, Each of the plurality of tap changers comprises: One end of the base is provided with a plurality of tap terminals, and the other end of the base is provided with two fixing legs fixed to the plate member, At least one of the fixing legs is fixed to the plate member together with fixing legs of other tap changer bases.

2. The plurality of tap changer stands are arranged in series, 2. The tap changer unit according to claim 1, wherein the two fixing legs of the remaining tap changers other than the tap changer at both ends are fixed to the plate member together with the fixing legs of the other tap changers.

3. Among the tap changer bases at both ends, the two fixed legs of the tap changer base at one end have the same length; The tap changer at the other end and the remaining tap changer are Of the two fixed legs, one of the fixed legs is shorter in length than the other fixed leg, 3. The tap changing unit according to claim 2, wherein the length of the other fixed leg is the same as the length of the fixed leg of the tap changing base at one end.

4. A first through hole is formed in the other end of the fixed leg of the one end tap changer and the other end of the other fixed leg of the remaining tap changer, The tap changer unit according to claim 3 , wherein the remaining tap changer and the other end tap changer are each formed with a second through hole larger than the first through hole at the other end of one of the fixed legs.

5. An engagement protrusion is formed on the other end of the fixed leg of the tap changer at one end and on the other end of the other fixed leg of the remaining tap changer, 5. The tap changer unit according to claim 3, wherein the remaining tap changer and the other end tap changer are each provided at the other end of one of the fixed legs with an engaged portion adapted to engage with the engaging projection.

6. A tap changer for use in a tap changer unit for a transformer in which a plurality of tap changers are attached to a plate member, comprising: One end of the base is provided with a plurality of tap terminals, and the other end of the base is provided with two fixing legs fixed to the plate member, The tap changer has one of the two fixed legs having a length shorter than the other fixed leg.

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