JPH11329870A - On-load tap changer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts items of an on-load tap changer without changing the function of the tap changer at all from a conventional function of the tap changer to contrive compaction of the structure of the tap changer, and also to make it possible to manufacture the tap changer at low cost. SOLUTION: In a tap selector, which is formed into a structure, wherein taps of transformer tap winding wire are suspended from the bottom of a changeover switch for changing over the taps from one tap into the tap adjacent to the one tap, and fixed contacts connected with the taps by an intermittent gear mechanism 33, are selected in order, and is provided with moving contacts, insulating sheets 46 are used instead of insulating support pillars. Groups 50 of the fixed contacts mounted with the fixed contacts 52 and 53 are provided on the circumferences of both surfaces of these insulating sheets 46 according to the number of the phases of a transformer, an insulating support 47 is clamped integrally with a metal support 31 by studs 44 through between a divider and the metal support 31 at the lowest step of the tap selector. At the same time, a group 55 of the moving contacts is provided into a rotatable constitution in an open part 51 provided centering around an insulating cylinder 34 held by the supports 31 and 47 on the insulating sheets of the groups 50. The fixed contacts are selected in order according to the intermittent operations of the intermittent gear mechanism 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-load tap changer for switching a tap of a transformer tap winding having a plurality of taps from one tap to an adjacent tap at the time of load.

[0002]

2. Description of the Related Art In general, a load tap changer is constituted by a changeover switch for cutting off a load current and a tap selector for selecting a tap in a no-current state, and these are built in a transformer tank.

FIG. 4 shows a representative example of Japanese Patent Publication No. 60-380.
14 shows a built-in on-load tap changer disclosed in Japanese Patent Application Publication No. 14 (JP-A-14). In FIG. 4, reference numeral 1 denotes an upper cover of a transformer tank, and the upper cover 1 has an opening,
The head 2 of the on-load tap changer is oil-tightly mounted so as to close this opening. A switching switch 3 is fixed to the lower surface of the head 2, and a tap selector 5 is suspended below the switching switch 3, and these are built in a transformer tank. Reference numeral 4 denotes a drive insulated shaft that moves the rotating part of the tap selector 5 by receiving power from an electric operation mechanism (not shown).

The tap selector 5 comprises a main switch 6 and a sub switch 7 which operates only at a specific operation position of the main switch 6, and is attached to a lower portion of the switch 3 by a cover 8. .

A drive mechanism 9 is provided in the cover 8, and the drive mechanism 9 includes a gear mechanism 10 for transmitting power and an intermittent gear mechanism 1 for intermittently rotating movable contacts of main and sub-switches.
1 and both are made of metal having a power transmission function.

The main switch 6 has an insulating cylinder 12 at the center thereof, and six current collecting rings 13 on the outer peripheral side of the insulating cylinder 12.
Are provided at equal intervals in the axial direction, and are connected to the switching switch by a connection line 14 from the inner peripheral side. Reference numerals 15 and 16 denote insulating cylinders for driving the movable contact 17, the upper end of which is an intermittent gear mechanism 11, and the lower end of which is a metal driven arm 18, 19 for performing smooth rotation along the rotation trajectory of the upper end. Each is installed.

[0007] Further, reference numeral 20 denotes a plurality of insulating posts arranged in accordance with the number of taps, and six fixed contacts 21 are mounted on the insulating post 20 at equal intervals in the axial direction, and the upper end thereof is driven. The lower end of the mechanism 9 is fixed to the upper support 22 and the lower end of the mechanism 9 is fixed to the lower support 23. The movable contact 17 is intermittently operated by the intermittent gear mechanism 11 and the drive insulating cylinders 15 and 16 to sequentially select the fixed contact 21 and form an energizing path between the movable contact 17 and the current collecting ring 13.

The sub-switch 7 has an intermittent gear mechanism 11 at the upper end.
In addition, an insulating shaft 25 whose lower end is rotatably supported by a lower support 24 is provided, and three movable contacts 26 are attached to the insulating shaft 25 at equal intervals in the axial direction. Further, an insulating support 27 is provided in parallel with the insulating shaft 25, and the upper end is fixed to the upper support 22 and the lower end is fixed to the lower support 24. A fixed contact 28 is attached to the insulating column 27 so as to correspond to the movable contact 26, and the movable contact 26 is switched to any of the fixed contacts 28 in conjunction with a specific position of the main switch 6. .

The lower supports 23 and 24 are all made of metal. On the other hand, a potential line 29 is provided in the center of the insulating cylinder 12 in the axial direction, and this potential line 29 is a connection line for giving the lower supports 23 and 24 a potential.
The cover 8 of the drive mechanism 9 is connected to the lower support 23. Here, when the transformer winding is a three-phase star connection, the tap winding is arranged on the neutral point side, and the neutral point is placed in the switching switch. This is because it is most advantageous for the on-load tap changer.

In this case, all metal parts other than the current path connected to the tap winding are connected so as to have a neutral potential. Further, between the neutral point and the fixed contact at which the highest potential is selected, power is applied between all taps corresponding to the total number of turns of the tap winding. Therefore, the upper support 22 and the lower supports 23 and 24 have an insulation distance that can withstand all tap voltages.

[0011]

The load tap changer constructed as described above has the following drawbacks in that it is manufactured in a compact and inexpensive manner, which has been increasingly required in recent years. (1) Since the insulating pillars 20 are arranged in the circumferential direction according to the number of contacts, and the lower part is fixed by screwing, the upper support 22 and the lower supports 23 and 24 need to be made of metal. Become. In addition, as shown in FIG. 4, the shape is complicated, so that it is manufactured by casting and finished by machining, so that the cost is high. (2) As described above, since the voltage of all taps is applied between the lower supports 23 and 24 and the lowermost fixed contact, insulation is necessary, and the overall height is increased accordingly. Furthermore, when the transformer is mounted on the transformer, a ground insulation distance is required between the tank and the tank at the ground potential, which leads to an increase in the size of the entire transformer. (3) The drive insulating cylinders 15 and 16 of the movable contact 17 naturally become longer due to the increase in the overall length, and unless the driven arms 18 and 19 are provided at the lower end, a normal rotation trajectory cannot be obtained. Therefore, the rotating parts of the driven arms 18 and 19 require members such as ball bearings, which is one of the reasons why the lower support must be made of metal. (4) Upper cover 8 to apply potential to lower support
Since the potential line is connected through the center of the insulating cylinder 12, the connection line passes from the current collecting ring 13 of each phase, and the voltage between the taps is imposed during this. Accordingly, it is necessary to enlarge the cylinder.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an on-load tap changer which is compact as a whole, has a reduced number of parts, and can be manufactured at low cost.

[0013]

According to the present invention, in order to achieve the above object, a load tap changer is constituted by the following means. According to a first aspect of the present invention, there is provided a switching switch for switching a tap of a transformer tap winding from one tap to an adjacent tap, and a switch suspended from a bottom of the switching switch and connected to the tap by an intermittent gear mechanism. And a tap selector provided with a movable contact for sequentially selecting fixed contacts, wherein one face is attached to the bottom of the switching switch, and the other face is provided with an intermittent gear mechanism via a bearing. A rotatable metal support, a terminal having a connection terminal attached to the metal support and connected to the switching switch, a stud provided at the lowermost stage corresponding to the metal support, and a stud passing through the metal support. One end to the metal support through the center of rotation of the intermittent gear mechanism, and the other end to the insulation support. An insulating cylinder held and held, and a plurality of fixed contacts disposed on the outer peripheral side of the insulating cylinder according to the number of transformer phases and connected to odd-numbered taps among fixed contacts connected to the tap on one surface of the insulating plate. A plurality of fixed contacts are mounted on the other surface so as to correspond to a fixed contact group provided with a plurality of fixed contacts connected to even-numbered taps and an outer peripheral surface of the insulating cylinder in correspondence with each fixed contact of the fixed contact group. A movable contact is attached to an insulated driving plate having one end fixed to the output end of the intermittent gear mechanism, and the movable contact is used to bridge the fixed contact and the current collecting ring to energize. A movable contact group forming a path, disposed in the insulating cylinder, and one end is connected to the current collecting ring;
A connection line connected to a connection terminal of the terminal, the movable contact group being rotatable within an opening provided on the insulating plate of the fixed contact group around the insulating cylinder. The fixed contact is sequentially selected according to the intermittent operation of the intermittent gear mechanism.

According to a second aspect of the present invention, in the load tap changer according to the first aspect of the present invention, the movable tap group is connected to the other end of the drive insulating plate of the movable contact group fixed to the output end of the intermittent gear mechanism. A guide groove for providing a dynamic bearing and engaging the end face of the rolling bearing with the insulating support to guide the drive insulating plate so as to have the same locus as the rotation locus of the output end of the intermittent gear mechanism. It is configured to be provided.

According to a third aspect of the present invention, in the load tap changer according to the second aspect of the present invention, the rolling bearing has a ball unit made of an insulator which rolls along a guide groove. It comprises a spring for pressing the unit and a bearing case for accommodating the ball unit and the spring.

According to a fourth aspect of the present invention, in the load tap changer according to the first aspect of the present invention, the fixed contact group includes a fixed contact connected to an odd tap provided on one surface of the insulating plate; The fixed contacts connected to the even-numbered taps provided on the other surface are configured to be fixed to convex portions provided on both surfaces of the insulating plate.

Therefore, in the load tap changer according to the present invention corresponding to the first to fourth aspects, the function can be reduced and the structure can be made compact by reducing the number of parts without changing at all. It can be manufactured at low cost.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B show a first embodiment of an on-load tap changer according to the present invention, wherein FIG. 1A is a plan view of a tap selector, and FIG. 1B is an arrow view along line XX of FIG. It is sectional drawing.

In FIGS. 1 (a) and 1 (b), reference numeral 31 denotes a metal support connected to a cover attached to a lower portion of a switching switch (not shown). The metal support 31 has a through hole at a substantially central portion. A cylindrical portion having an appropriate length communicating with the hole is integrally formed below.

A drive shaft 32 is inserted through one side of the metal support 31 so as to be rotatable by a bearing. The drive shaft 32 receives power from an electric operating mechanism (not shown) via a connection pin 32a. The transmission 31 is connected to an intermittent gear mechanism 33 provided on the lower surface side of the transmission 31.

An insulating tube 34 is provided through a cylindrical portion substantially at the center of the metal support 31. A terminal 35 is disposed at the upper end of the insulating tube 34, and the terminal 35 is oil-tightly mounted with bolts. Oil tightly closed. The terminal 35 is made of an insulator cast product, and a plurality of connection terminals 37 are radially provided on the outer periphery thereof.
Are arranged evenly. In this case, the terminal 35 is made of an insulator-cast product because it is necessary to form a through portion of the connection terminal 37 in an airtight manner, and it is necessary to maintain proper insulation between the connection terminals 37. It is. In addition, the entire terminal 35 can be made compact.

The output end of the intermittent gear mechanism 33 is rotatably supported by a cylindrical portion of the metal support 31 via a bearing 38. A cylindrical step is formed at the lower end of the insulating tube 34, and is fixed by engaging with a hole 47a of an insulating support 47 provided at the lowest stage. Also, the insulating tube 3
Four current collecting rings 39 are provided at equal intervals in the axial direction on the outer peripheral side of 4, and a connecting wire 42 is connected and fixed to the connecting terminal 37 from the inner peripheral side via a terminal 41 by bolts 43. An energization path is formed.

Therefore, the outside of the connection terminal 37 is slidably contacted with a slide contact (not shown) from the switching switch to form an energizing path between the switching switch and the tap selector. Further, through studs 44 are arranged in the four corners of the metal support 31 in the axial direction, and the through plates 44 and the insulating support 47 of the three fixed contact groups 45 disposed below the metal support 31 are provided on the through studs 44. While maintaining the necessary spacing for insulation and structural arrangement.

Further, six main movable contacts are provided on a drive insulating plate 48 having one end attached to an output end of an intermittent gear mechanism 33 rotatably supported on a cylindrical portion of the metal support 31 via a bearing 38. 1 are mounted at equal intervals in the axial direction, and the rolling bearings provided at the other ends are provided with A in FIG.
As shown in an enlarged view of FIG. 2, a portion is supported movably along a ring-shaped guide groove 47b formed on the insulating support 47, and these constitute a main movable contact group 50.

The insulating plate 46 is provided with a circular opening 51 concentric with the center of the current collecting ring 39 so that the main movable contact group 50 can rotate. The insulating plate 46
The fixed contacts 52 and 53 connected to the odd and even taps of the tap winding at appropriate intervals on the upper and lower surfaces.
Is provided, and the main movable contact 54 of the main movable contact group 50 forms an energization path between the main movable contact 54 and the current collecting ring 39. In this case, the fixed contacts 52 and 53 are attached to one surface of the convex portion 46a provided on both surfaces of the insulating plate 46. These are provided to maintain the vertical creeping insulation distance, and to ensure insulation even if foreign substances that interfere with insulation accumulate on the horizontal surface.

On the other hand, 55 is a sub movable contact group which rotates by the intermittent gear mechanism 33. The sub movable contact group 55 is a drive insulating plate 56 whose upper end is connected to the intermittent gear mechanism 33.
And a movable contact 57 attached to the drive insulating plate 56 at equal intervals in the axial direction.

Reference numeral 58 denotes a fixed contact connected at the beginning and end of a tap winding (not shown). The fixed contact 58 is bridged by a movable contact 57 via a current collector 59 mounted on an insulating plate 46. To form an energization path. Drive insulating plate 56
Roller bearings are provided at the lower end of the main body as in the case of the main switch. As shown in FIG.
Are supported so as to be movable along a guide groove 47c provided in the groove.

In this case, similarly to the main movable contact side, an opening 60 is provided in the insulating plate 46 on the sub movable contact side, and the sub movable contact group 55 is configured so as to be able to rotate therein. FIG. 3 shows details of the rolling bearing 61. 62
Denotes a bearing case, which is fixed to the drive insulating plates 48 and 56, and a large spring of the ball unit 64 is guided by the compression spring 63 into the guide grooves 47b and 47b.
47c so that an appropriate guide function can be exhibited.

In this case, the ball unit 64 is configured to use a plurality of small balls so as to cover the large ball and its surroundings so that the rolling operation of the large ball becomes free. Ball unit 64
Are all made of insulating material in order to suppress wear of the guide groove of the insulating support.

In the tap selector of the on-load tap changer having such a configuration, when power from an electric operating mechanism (not shown) is transmitted to the drive shaft 32, the drive shaft 32 transmits the power via the connection pin 32a. To the intermittent gear mechanism 33.

Then, in response to the intermittent operation of the intermittent gear mechanism 33, the main movable contact group 50 intermittently operates, and the fixed contact group 45
The movable contact 54 sequentially contacts the fixed contacts 52 and 53 connected to the taps of the tap windings, and the tap switching operation is performed.

The sub movable contact group 55 operates at a specific position in the switching operation of the main switch 50, and the two fixed contacts 58 are switched by the movable contact 57, and the connection is changed at the beginning and end of the tap winding.

As described above, in the tap selector of the on-load tap changer according to the embodiment of the present invention, the fixed contact is arranged on the insulating plate instead of the conventional insulating column, and the lowermost stage is constituted by the insulating support. As a result, the whole is compact, the number of parts is reduced, and it can be manufactured at low cost. The specific effects are as follows. (1) Since the fixed contacts 52 and 53 are attached to the insulating plate 46, an upper support as in the related art, a cover having a complicated component shape for attaching and fixing the upper support, and a lower support at the lower portion are unnecessary. Therefore, it is possible to reduce the processing cost of the casting material, the machining finish, and the like, and it is possible to significantly reduce the manufacturing cost. (2) Since the lowermost support can be configured with an insulating plate, insulation of all taps is not required and insulation between the transformer tank and the ground can be greatly reduced. The size of the entire transformer can be reduced. (3) The guides at the lower ends of the main movable contact group 50 and the sub movable contact group 55 are formed by guide grooves 47 b provided in the insulating support 47.
Since it can be supported responsively to the intermittent operation by the 47c and the rolling bearing 61, the driven arm and its bearing are not required. (4) Since the terminals 36 having the six connection terminals 37 are arranged on the metal support 31, the connection lines can be formed substantially in a straight line and pass through the center of the metal support 31. , The whole can be greatly simplified. (5) The potential wire to the lower insulating support 47 becomes unnecessary, and the insulation of the central connection line 43 is reduced, so that the outer diameter of the main switching portion can be reduced.

[0034]

As described above, according to the present invention, there is provided an inexpensive on-load tap changer capable of reducing the number of parts and achieving a compact structure without changing the function at all. Can be.

[Brief description of the drawings]

FIGS. 1A and 1B show an embodiment of a load tap changer according to the present invention, wherein FIG. 1A is a plan view of a tap selector, and FIG.
3A is a cross-sectional view taken along line XX of FIG.

FIG. 2 is a plan view of the insulating support in the embodiment.

FIG. 3 is a detailed view of a rolling bearing mounted on a drive insulating plate which engages with a guide groove of the insulating support in the embodiment.

FIG. 4 is a configuration diagram showing a cross section of a main part of a typical example of a conventional load tap changer.

[Explanation of symbols]

 31 metal support 33 intermittent gear mechanism 34 insulating cylinder 36 terminal 39 collecting ring 43 connecting wire 44 through stud 45 fixed contact group 46 insulating plate 47 Insulating support 47b, 47c Guide groove 50 Main movable contact group 51, 60 Opening 52 Main fixed contact 54 Movable contact 55, 57 Sub movable contact 61 Rolling bearing 63 … Ball unit

Claims (4)

[Claims] 1. A switching switch for switching a tap of a transformer tap winding from one tap to an adjacent tap, and a fixed contact suspended from the bottom of the switching switch and connected to the tap by an intermittent gear mechanism. A load tap changer comprising a tap selector having a movable contact to be sequentially selected, wherein one surface is attached to the bottom of the changeover switch, and the intermittent gear mechanism is rotatably connected to the other surface via a bearing. A supported metal support, a terminal having a connection terminal attached to the metal support and connected to the switching switch, and provided at the lowermost stage corresponding to the metal support, and integrally provided with a stud through the metal support. One end of the insulating support is fastened to the metal support through the center of rotation of the intermittent gear mechanism, and the other end is connected to the insulating support. A held insulating cylinder and a plurality of fixed contacts arranged on the outer peripheral side of the insulating cylinder according to the number of transformer phases and connected to the taps on one surface of the insulating plate and connected to the taps. The fixed contact is mounted on the other surface of the insulating cylinder in correspondence with each fixed contact of the fixed contact group, the fixed contact group provided with a plurality of fixed contacts connected to the even-numbered taps. A movable contact is attached to an insulated driving plate having one end fixed to the output end of the intermittent gear mechanism, and a bridging path between the fixed contact and the current collecting ring by the movable contact. A movable contact group formed in the insulating cylinder, one end of which is connected to the current collecting ring, and the other end of which is connected to a connection terminal of the terminal. The contact group is provided on the insulating plate of the fixed contact group. An opening portion provided around the edge tube as rotatable configuration, load tap changer, characterized in that so as to sequentially select the fixed contacts in accordance with the intermittent operation of the intermittent gear mechanism. 2. A rolling bearing is provided at the other end of a drive insulating plate of a movable contact group fixed to an output end of an intermittent gear mechanism, and said insulating support is engaged with an end face of said rolling bearing. 2. The on-load tap changer according to claim 1, wherein a guide groove for guiding the drive insulating plate so as to have the same locus as the rotation locus of the output end of the intermittent gear mechanism is provided. 3. A rolling bearing includes an insulating ball unit that rolls along a guide groove, a spring that presses the ball unit, and a bearing case that houses the ball unit and the spring. The on-load tap changer according to claim 2, wherein: 4. The fixed contact group includes fixed contacts connected to odd-numbered taps provided on one surface of the insulating plate and fixed contacts connected to even-numbered taps provided on the other surface of the insulating plate, respectively. The on-load tap changer according to claim 1, wherein the tap changer is configured to be fixed to a convex portion formed on the tap.