JPH11283849A - Tap changer under load - Google Patents

Abstract

(57) [Summary] An object of the present invention is to reduce the size and cost of the entire apparatus. In a load tap changer using one current limiting resistor and two vacuum valves, a cam attached to a driving shaft 2 that is rotated by a driving force applied from the outside to open and close the vacuum valve. 4. A drive shaft 2 is provided on the outer periphery of the cam.
A vacuum valve opening / closing mechanism 30 provided directly in connection with a vacuum valve arranged in parallel with the vacuum valve, and having an operating portion that operates in the axial direction by turning the cam to open and close the vacuum valve, and provided at a lower portion of the cam. The idler mechanism 40 having a driven part that provides a fixed time difference between the opening point of the vacuum valve and the separation point of the changeover switch, and a movable part 50 having a current collecting ring and a movable contact attached to the driven part of the idler mechanism And a changeover switch S which can be switched by a movable contact of the movable portion at a fixed contact disposed outside the movable portion.

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 the taps of a transformer tap winding at the time of load and adjusting the voltage, and in particular, a load using one current limiting resistor and two vacuum valves. Time tap changer.

[0002]

2. Description of the Related Art In recent years, demands for downsizing and cost reduction of equipment have been increasing. In order to achieve this, it is necessary to devise a system and configuration that can exhibit the required functions with the minimum elements.

As is well known, the on-load tap changer includes a switching switch for interrupting a load current at the time of load and transferring the current to an adjacent tap, and a tap selector for selecting a tap of a tap winding to a required position. Have been. The latter only needs to be able to select a tap and supply a load current, and since the configuration is simple, the proportion occupied in cost is small. For the former, the most important issue is to select a switching method. That is, since the switching switch has an arc contact that directly cuts off the load current, a mechanism for making the contact differential, a quick-off mechanism for making the differential at a constant speed, and such that they function more than fully. Therefore, the structure is complicated, the number of parts is increased, and the cost is increased.

[0004] On the other hand, from the viewpoint of maintenance, in the oil shut-off system, the insulating oil is contaminated by thermal decomposition, so that it is necessary to provide a device for purifying the oil or replace the oil at regular intervals. In addition, downsizing of the tap changer under load and cost reduction cannot be attained without improving the changeover switch, for example, the maintenance cost is increased.

[0005] In recent years, as a method of reducing maintenance costs, a method using a vacuum valve instead of the oil cutoff method has become widespread.

Various methods using this vacuum valve have been devised and disclosed. Among them, a method using a single current limiting resistor and a single resistor using two vacuum valves has been proposed. There is a two-valve type.

FIG. 7 shows such a system as a circuit configuration diagram, and its operation will be described below. In FIG. 7A, T1 and T2 are taps of a transformer winding, and M1 and M2.
Is the movable contact of the tap selector, S1 and S2 are the movable contacts M
1, a fixed contact of a changeover switch S connected in series to M2,
Sm is a movable contact bridging the current collection ring S0 and the fixed contact S1 or S2, and V1 is a main valve having one end connected to the current collection ring S0 and the other end connected to the neutral point N.

R is a resistor for limiting the circulating current between the taps. One end is connected to the fixed contact S2, and the other end is connected to the neutral point N via the resistance valve V2.

Next, the operation of the on-load tap changer having the above configuration will be described.

FIG. 7A shows the operation state at the tap T1, and the flow of the load current during this operation is indicated by a thick line.

FIG. 7B is an explanatory diagram of the operation.
When the operation state is at the tap T1 as in the above, the circulating current Ic flows as shown by the closing of the resistance valve V2. Next, as shown below, when the main valve V1 opens and cuts off the current, the current moves to the resistance valve V2 side. afterwards,
As shown in (1), the movable contact Sm of the changeover switch starts to move, and as shown in (2), the closing of the movable contact Sm is completed. Then, the main valve V1 closes and one tap switching operation ends, as shown in FIG.

The above is the switching operation from the tap T1 to T2. Conversely, the switching from the tap T2 to T1 is the reverse operation of the tap, so that the description is omitted here.

By the way, as a conventional load tap changer, there is one having a configuration as shown in FIG. 22, for example. FIG. 22A is a longitudinal sectional view of a load tap changer, and FIG. 22B is a sectional view taken along line XX of FIG.

In FIGS. 22 (a) and 22 (b), reference numeral 102 denotes a drive shaft rotatably held at two appropriately separated positions by a plate 106 and an insulating support 119. The drive shaft 102 uses a spring as an energy source. The rotational power is transmitted from the energy storage device 101 that reciprocates in a certain range.

Reference numeral 108 denotes a cam fixed to the drive shaft 102 inside the plate 106. The cam 108 has two grooves 108a and 108b for the main valve and the resistance valve.
have. A cam follower 111a or 111b attached to the slider 112a or 112b is rotatably engaged with these grooves 108a and 108b, and moves the slider up and down with the displacement of the grooves.

The sliders 112a and 112b are fixed to a slide unit 109b of a rectilinear guide 109 fixed to a rail 109a on a holding table 110 attached to a plate 106, and repeatedly move up and down by movement of a cam follower 111a or 111b.

The sliders 112a, 112b
Has a cylindrical portion, in which a wipe rod 114 is provided.
A disk attached to one end of each of a and 114b is engaged, and a movable contact 117a of a main valve 115a and a resistance valve 115b is screwed to the other end. This wipe rod 11
Wipe springs 113a and 113b are interposed between the disk attached to one end of 4a and 114b and the end surface in the cylindrical portion, and apply a contact pressure necessary for energization to the movable contact 117a.

FIG. 23 shows the wipe rod 114 and the movable contact 1.
17A and 17B show the details of a connection portion with No. 17;
(B) is a side view. As shown in FIGS. 23 (a) and 23 (b), the wipe rod 114 is
17d is fastened and fixed by a screw nut 131 to transmit power. Further, a connection piece 130 for passing an electric current is screwed into a male screw 117c formed on the outer peripheral surface of the movable contact 117a, the periphery is tightened with a tightening bolt 132, and the connection is made to the neutral point N via the flexible conductor 116. To form an energization path.

On the other hand, in FIG. 22, reference numeral 118 denotes a conductor mounted on the insulating support 119, and 120 denotes an insulating cylinder mounted concentrically with the drive shaft 102 on the inner diameter side of the insulating support 119. Fixed contact 11
7b and the current collecting ring 121 (S0) of the changeover switch S are connected. 122 is a collector ring 1 on the inner surface of the insulating cylinder 120.
21 (SO) and a fixed contact attached at a predetermined interval, and comes in contact with the movable contact Sm.

Reference numeral 150 denotes a movable part fixed to the drive shaft 102 below the insulating support 119.
50 has a function as a changeover switch S by rotating the movable contact Sm with the rotation of the drive shaft 102.

Next, the operation of the on-load tap changer having the above configuration will be described.

FIG. 24 shows the main valve 115a and the resistance valve 1
It is operation | movement explanatory drawing of the cam mechanism which opens and closes 15b, and a changeover switch. As shown in FIG. 24, the cam 108 has a vertically displaceable groove.
(111b) → Slider 112a (112b) → Wipe rod 11 via wipe spring 113a (113b)
4a (114b) → The movable contact 117a is moved to open and close the fixed contact and the movable contact. Hereinafter, the operation will be described in comparison with FIG. 7. First, the operation when the cam follower moves from the M1 direction to the M2 direction along the groove by the rotation of the cam will be described with reference to FIGS.

The drive shaft 10 is driven by the output of the energy storage device 101.
When 2 rotates, the cam 108 also rotates integrally therewith.
First, the rotation of the cam 108 causes the cam follower 111 to rotate.
When b moves upward along the resistance valve groove 108b, the slider 112b moves upward. And
This movement of the slider 112b is transmitted to the wipe rod 114b via the wipe spring 113b, and the resistance valve V
2 opens [of FIG. 7 (b)].

Time t4 after the resistance valve V2 is opened
Then, the cam follower 111a is displaced upward along the main valve groove 108a, so that the main valve V1 is opened through the same movement transmission path as described above (see FIG. 7B).

At this time, the movable contact Sm is rolling on the fixed contact S1 while the movable portion 150 of the changeover switch is rotated and energized. When the time t1 elapses, the movable contact Sm separates from the fixed contact S1 (see FIG. 7B).

Further, when the rotation of the drive shaft 102 rotates and the time t2 elapses, the movable contact Sm contacts the opposite fixed contact S2 and rotates [FIG. 7 (b)]. And
After time t3, the cam follower 111a of the main valve V1 is displaced downward along the main valve groove 108a, so that the main valve groove 108a is closed [FIG. 7B]. At this time, the movable contact Sm repeats the rolling operation to the end while being energized, and finally stops.

The above is a case where the cam follower moves from the M1 direction to the M2 direction along the groove due to the rotation of the cam. On the contrary, the operation from the M2 direction to the M1 direction is the reverse operation. That is, as shown in FIGS. 24 (b) and (d), the cam follower moves from right to left in the drawing, and the operation order is reversed. First, the main valve V1 opens, and after t3, the changeover switch S opens. Then, after t2, the changeover switch S
Is closed, and after t1, the main valve V1 is closed.
After four, the resistance valve V2 closes.

Here, similarly to the above, the movable contact Sm continues to roll in an energized state even after the main valve V1 is closed, and stops. As is clear from the drawing, the switching times of the switching contacts t1 to t4 are almost the same in the directions of M1 → M2 and M2 → M1.

This is caused by the fact that the cam 108 and the movable portion 150 are directly connected and fixed to the drive shaft 102, so that the rotation is symmetrical in both forward and reverse rotations.

[0030]

As described above, the conventional on-load tap changer has the following problems with respect to the market need to be compact and inexpensive to manufacture.

(1) When the main valve V1 shuts off the current,
The new product is easy to extinguish the arc because the contact surface is smooth, but as the wear gradually progresses, severe irregularities occur on the surface. For this reason, it is difficult to extinguish the arc, and what was 10 ms at the time of a new article is extended to 20 ms. To cover this Figure 24
(C) t1 and t3 shown in (d) are at least 20 ms
It is necessary to give a margin to

As described above, the operation is symmetrical.
The entire switching time T must be long. Therefore, it is necessary to increase the outer diameter of the cam 108 and extend the circumferential distance to take a distance from the open / close point of the changeover switch S, that is, to take time.

As a result, the whole becomes larger and the moment of inertia increases by the increased size, so that the energy storage device as a driving source becomes larger.

(2) Since the drive shaft 102 and the movable part 150 are directly connected, the movable contact Sm rolls when the main valve V1 is closed and energized. Even if there is no problem, there is a possibility of breaking and arcing when an abnormal impact is applied. Therefore, if two or more sets are provided to form a parallel circuit, the size becomes large and the cost increases.

(3) Since the movable contact Sm of the movable section 150 comes into contact with the inner peripheral surfaces of the fixed contacts S1 and S2, a roller-type contact that rolls is effective.

Since the roller rolls in an energized state, there is a possibility that the opening and firing will occur due to vibration during operation only with a spring force necessary for energization, so it is necessary to increase the strength several times. As a result of keeping the roller-type contacts and the members supporting the contacts strong, the weight is large and the size is large.

Further, since the moment of inertia increases, it is necessary to provide a suitable shock absorber.

(4) In the opening / closing mechanism for opening and closing the main valve and the resistance valve, the cam follower 111 engaged with the cam groove receives a force in the rotational direction in addition to the vertical movement due to the displacement of the groove 108. These loads are applied to the straight guide 109
And it is received by the holding table 110 that holds it, but since it is located at a position distant from the cam outer peripheral surface, it acts as a bending load. Therefore, in order to be able to withstand frequent opening and closing, the holding part 110 has a strong configuration.

(5) Movable shaft 11 of main valve and resistance valve
A connecting piece 130 screwed and connected to a male screw 117c formed on the outer peripheral surface of 7a forms an energization path, and is operated by a wipe rod 114 screwed into a female screw 117d provided on the movable shaft 117a. Since it is separated into two functions, two systems are required. In addition, in the frequent opening and closing, since the screw diameter of the wipe rod 114 screwed into the female screw 117d can be only about 10 mm, the material of the wipe rod 114 is expensive because a tough material must be selected.

(6) A cam follower 111, a slider 112, a straight guide 109, and a holding tube 110 for operating the main valve and the resistance valve are arranged on the outer periphery of the cam 108.
Due to the configuration in which the valve is mounted below the space, the space between the inside of the valve and the outer peripheral portion of the drive shaft 102 becomes a dead space, which causes an increase in size.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a load tap changer capable of reducing the size and cost of the entire apparatus.

[0042]

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 movable contact for switching between fixed contacts connected to a plurality of taps provided in a transformer tap winding and slidingly on a current collecting ring. A changeover switch having a contact point, and one current limiting impedance and two vacuum valves are connected in series between the current collecting ring and one adjacent tap of the changeover switch; A load tap changer for switching the taps of the transformer tap winding by opening and closing the two vacuum valves by a driving force applied from the outside and limiting a circulating current flowing between adjacent taps by the current limiting impedance; , A driving shaft that is rotated by a driving force given from outside, a cam attached to the driving shaft to open and close the vacuum valve, and the drive A vacuum valve opening / closing mechanism provided directly in connection with a vacuum valve arranged in parallel with, and having an operating portion that operates in the axial direction by turning the cam to open and close the vacuum valve; and a lower portion of the cam. An idler mechanism having a driven portion that provides a fixed time difference between the opening point of the vacuum valve and the separated point of the changeover switch, the current collector ring and the movable contact attached to the driven portion of the idler mechanism. A movable portion having a movable contact, and a fixed switch disposed outside the movable portion, a changeover switch adapted to be switched by the movable contact included in the movable portion. The mechanism and the movable part of the changeover switch are arranged coaxially with the drive shaft.

According to a second aspect of the present invention, in the load tap changer according to the first aspect of the present invention, the vacuum valve opening / closing mechanism includes two cams each having an appropriate position in a circumferential direction of the cam displaced in the axial direction. And a cam follower rotatably mounted on the drive boss is engaged with the groove to receive a load acting on the cam follower at a symmetrical position around the cam follower with the rotation of the cam, and the cam groove is provided. Two guide rods for guiding the drive boss in the direction in which the drive boss is displaced are engaged with an open / close boss that operates the drive boss at a fixed interval, and the open / close boss is screwed to a movable contact shaft of the vacuum valve. The power supply function and the actuation force transmission function are fixed by using a fixing method.

According to a third aspect of the present invention, in the load tap changer according to the first aspect of the present invention, the idling mechanism includes a first coupling having a convex portion attached to the drive shaft and the first coupling. A second coupling having a concave groove having an idling angle and a restricting concave groove for restricting an operation range and engaging with a stopper pin, the second coupling comprising: The first coupling and the second coupling are attached to a movable portion of a changeover switch, and the first coupling and the second coupling are arranged so that a predetermined time difference is generated between a cam that provides an opening / closing operation to a vacuum valve and the changeover switch, and the operation of the changeover switch The range is configured so as to restrict the range to a predetermined range.

According to a fourth aspect of the present invention, in the load tap changer according to the first aspect of the present invention, the idling mechanism is the first idling mechanism according to the third aspect. A second pair of gear mechanisms directly connected to the second coupling and an intermittent mechanism directly connected to the gear mechanism, the changeover switch being operable by the intermittent mechanism;
The first idling mechanism and the second idling mechanism are configured to add a second idling to the first idling so that a further time difference occurs between the vacuum valve and the changeover switch. ,
At the time when the vacuum valve is turned on, the switching operation of the changeover switch is completed so as to be in a stationary state.

According to a fifth aspect of the present invention, in the load tap changer according to the fourth aspect of the present invention, the gear mechanism directly connected to the second coupling is a pair of spur gears, and the intermittent directly connected to the spur gears. The mechanism comprises a driver having one drive pin and an intermittent gear having one drive groove and two restraining grooves.

According to a sixth aspect of the present invention, in the load tap changer according to the first aspect of the present invention, the changeover switch is attached to a driven portion of the idling mechanism and is rotatably held on a drive shaft. A current collecting ring is attached to the outer peripheral portion of the insulating shaft, and a slide contact for slidingly contacting one end of the current collecting ring is arranged from the current-carrying table on which the vacuum valve is mounted toward the center of the drive shaft. A movable contact for alternately switching two fixed contacts provided outside thereof is attached to the other end so as to be able to conduct electricity.

According to a seventh aspect of the present invention, in the load tap changer according to the sixth aspect of the present invention, the current collecting ring mounted on the insulating shaft of the movable portion of the changeover switch is divided into three parts, each of which is predetermined. Are arranged with an insulation distance of 1 mm, and one end of each of them is brought into sliding contact with a slide contact, and a movable contact for alternately switching a fixed contact is attached to the other end, thereby forming a three-phase device.

According to an eighth aspect of the present invention, in the on-load tap changer according to the sixth aspect of the present invention, the contacts are provided on a pair of flexible copper foils respectively fixed to the front and back surfaces of the current collecting ring of the changeover switch. A movable contact is constructed by attaching the fixed contact to the movable contact so as to sandwich the fixed contact to form an energizing circuit and a contact structure capable of exerting self-limiting by the frictional force generated by the contact force of the wipe spring. is there.

Therefore, in the on-load tap changer according to the first to eighth aspects of the present invention, it is necessary to secure the arc extinguishing time of the vacuum valve when the entire switching time T is constant. The switching time t1 is long and the closing time t3 is short so that the operation can be effectively utilized. In addition, the vacuum valve opening and closing mechanism is parallel to the drive shaft, and the idling mechanism and the movable part of the changeover switch are connected to the drive shaft. By arranging coaxially, dead space can be minimized and the whole can be manufactured compact.

[0052]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 4 show a first embodiment of the on-load tap changer according to the present invention.
(A) is a longitudinal sectional view, (b) and (c) are sectional views taken along line BB of (a), and FIG. 2 (a) is an arrow taken along line AA of FIG. 1 (a). FIG. 2B is a sectional view taken along the line EE of FIG. 2A, FIG. 3C is a sectional view taken along the line FF of FIG. 2A, and FIG. FIG. 4 is a sectional view taken along the line C in FIG.
It is arrow sectional drawing which follows the DD line of (a).

In FIGS. 1 and 2, reference numeral 2 denotes a drive shaft. The drive shaft 2 is rotatably supported by bearings 8 on metal plates 3, 7 provided at positions corresponding to both shaft ends. The drive shaft 2 is directly connected to an output shaft of the energy storage device 1 that reciprocates in a predetermined range by using a spring as an energy source to transmit rotational power. Reference numeral 6 denotes an insulating support. The insulating support 6 is fixed to a support (not shown), and forms an entire framework.

4 is a drive shaft 2 on the lower surface side of the plate 3.
The cam 4 has grooves 4a and 4b which are displaced upward and downward at appropriate locations in the circumferential direction, and are formed in upper and lower stages.

A main valve V1 and a resistance valve V corresponding to each of the three phases U, V and W
2, a vacuum valve opening / closing mechanism 30 is provided.

The vacuum valve opening / closing mechanism 30 includes vacuum valves V1 and V2 having a fixed contact 42 and a movable contact 41.
An opening / closing boss 24 attached to and fixed to the movable contact 41 of the vacuum valve; and a groove 4 a, which is held by the opening / closing boss 24 via a wipe spring 25 and is provided on a side surface corresponding to the cam 4.
4b, a drive post 20 having a cam follower 21 rotatably mounted thereon, and an open / close boss 24 connected to a neutral point N via a flexible conductive wire 22 on the outer surface of the drive boss 20. I have.

Reference numeral 5 denotes a plate mounted on a drive shaft on the lower surface side of the cam 4 via a bearing, and an idling mechanism 40 is provided near the plate 5.

The idling mechanism 40 is connected to the drive shaft 2 by the connecting key 1
The first coupling 10 is fixed by the first coupling 1 and a second coupling 51 that performs an idling operation with the coupling 10 and is connected to a movable portion 50 described later.

Further, a changeover switch S is provided on the movable portion 50 attached to the drive shaft 2 below the idling mechanism 40.

As shown in FIGS. 3 and 4, the changeover switch S has an insulating shaft 53 connected to the drive shaft 2 with the second coupling 51 of the idling mechanism 40 around the drive shaft 2.
A current collecting ring So attached to the peripheral surface of the insulating shaft 53 so as to correspond to each of the three phases; a current supply table 71 attached to the fixed contacts 42 of the vacuum valves V1 and V2;
1 and a sliding contact 70 that slides on the current collecting ring So using the current as a current path.
The movable contact 60 is provided on the current collecting ring So below the fixed contact S, and the fixed contact S
A shut-off mechanism that enables selection of S1 and S2 with the rotation of the movable unit 50 is configured.

Here, the configuration of each part of the above-mentioned tap changer under load will be described in detail.

In the opening / closing mechanism 30, the groove 4 of the cam 4
The drive boss 21 to which the cam follower 21 engaged with the a and 4b is rotatably mounted is inserted through a through hole provided in the vicinity of the outer peripheral surface of the cam 4 through the linear guide 28 as shown in FIG. Both ends are vertically movable by two guide rods 29 fixed to the plates 3 and 5, respectively, and at the same time, the cam 4 is supported so as to smoothly rotate.

The opening / closing boss 24 is formed in a concave shape and incorporated in the driving boss 20, and a male screw 43 formed at the shaft end of the movable contact 41 of the vacuum valves V1 and V2 is provided at the bottom of the opening / closing boss. It is screwed into the screw hole to secure the power supply on the male screw surface, and the bolt 27 is screwed into the female screw 44 formed at the shaft end.
The screw is firmly fixed. Therefore, during the opening / closing operation, the two screw portions receive the operating force, so that the structure becomes more robust.

Further, a wipe spring 25 is provided in the recess of the opening / closing boss 24, one end of which is in contact with the driving boss 20, and the other end of which is in contact with the bottom of the hole of the opening / closing boss 24, to supply electricity according to the movement of the driving boss 20. The necessary contact force is given to the movable contact 41. A pair of left and right guide pins 26 are provided between the open / close boss 24 and the drive boss 20, and both of them are guided in a certain direction and can be operated.

On the other hand, flexible conductive wires 22a and 22b for the main valve and the resistance valve are connected to the outer surface of the drive boss 20, and these flexible conductive wires 22a and 22b are respectively connected to the neutral point N.
Connected to.

In the idling mechanism 40, the first coupling 10 connected to the drive shaft 2 by the connection key 11 is provided.
Has a convex portion as shown in FIGS. 1 (b) and 1 (c).
In addition, the second coupling 51 which is provided coaxially with the first coupling 10 and is fixed to the insulating shaft 53 and is a driven side is a first coupling with which the projection of the first coupling 10 is engaged. A second groove 51b for restricting an operation range on the opposite side of the first groove 51a, and an idling angle δ is provided between the first groove 51a and the convex portion of the first coupling 10. This delay operation due to the idling angle δ makes it possible to increase the time t1 between the switch S and the shutoff of the main valve V1. The second concave groove 51b is a groove for preventing the movable contact 60 of the movable portion 50 from operating excessively beyond the fixed contacts S1 and S2. The second concave groove 51b regulates the operation range by the stopper pin 9 attached to the plate 5. Ensure contact between movable and fixed contacts.

Here, FIG. 1B shows a normal stop state on the M1 side, and the arrow shows a direction from this state to M1 → M2.
Then, FIG. 1C shows a state in which the switching to the M2 side has been completed and the M2 side is normally stopped. The idling angle δ is obtained in both the M1 → M2 direction rotation and, conversely, the M2 → M1 direction rotation, and the time t1 until the main valve V1 and the changeover switch S open is secured.

Further, in the changeover switch S, the movable portion 50 rotates around the drive shaft 2 as a center of rotation. As shown in FIG. 5, the movable portion 50 includes a second coupling 51 having the two concave grooves and an insulating shaft 53 connected to the connecting pin 5.
2 and a bearing 55 is provided between the insulating shaft 53 and the drive shaft 2 so as to be mutually rotatable. Further, the current collecting rings 54 (So) are fixed to the insulating shaft 53 in correspondence with the three phases, respectively, and these rotate together with the drive shaft 2.

The upper side of the current collecting ring 54 is the main valve V1.
And a sliding contact 70 fixed to one end of the current-carrying base 71 so as to be able to conduct electricity, as shown in FIG. To form an energization circuit.

At one end on the lower side of the current collecting ring 54,
The movable contact 60 is fixed so as to be able to conduct electricity, and the fixed contacts S <b> 1 and S <b> 2 make switching contact with the rotation of the movable shaft 50.

In the present embodiment, the configuration of the three-phase device is shown. As shown in FIGS. 2 to 5, each of the three phases is equally divided in the circumferential direction and each phase is arranged.

FIG. 6 shows a detailed view of the movable contact 60 and the slide contact 70 of the changeover switch S, both of which have exactly the same structure.

In FIG. 6, reference numeral 61 denotes a flexible copper foil in which several tens of plate-shaped copper foils are laminated, and a U-shaped contact plate 66 is disposed on the upper surface of one end thereof. Flexible copper foil 61 from the side
A rivet is driven into the contact 64 provided on the lower surface side of one end of the rivet, and both are fixed. Further, the other end of the flexible copper foil 61 is fixed to the current collecting ring 54 via a current washer 63 by a bolt 67. This is attached to the front and back of the current collecting ring 54, and the fixed contacts S1 and S2 are contacted so as to sandwich the fixed contacts S1 and S2 to form a circuit.

In this case, a wipe spring 65 for applying a necessary contact pressure to the contact 64 is inserted into the contact plate 66, and the flexible copper foil 61 extends from the upper end of the wipe spring 65 to the other end of the flexible copper foil 61. A support 62 is provided so as to cover the foil 61. One end of the support 62 is held by bending the upper ends of both side surfaces of the support plate 66 in an L-shape, and the other end of the support 62 is used for fastening the flexible copper foil 61 and the current collecting ring 54. At this time, they are integrally fixed by bolts 67.

Here, the support 62 reinforces the flexible copper foil 61 so that the flexible copper foil 61 can withstand a load when the fixed contact is applied or slid. Further, the upper end of both sides of the contact plate 66 is bent inward to hold the support 62 because the contact 64 collides with the fixed contacts S1 and S2 particularly when the contact is closed, and the contact 64 slopes the slope of the fixed contact. This is so as to sufficiently withstand even the largest load acting upon sliding.

Further, even if a spring force acts on the contact 64, the L-shaped portions at the upper ends of the both sides of the contact plate 64 are hooked on the support 62, so that the flexible copper foil 61 is bent. Instead, a gap G is provided between the upper and lower contacts. By doing so, the impact force at the time of injection is reduced, and the useful life is increased.

The contacts thus configured are collectively referred to as a Pinch Finger Tip contact. The reason why this type of contact changeover switch S is used is that, as described above, the operating portion of the movable portion 50 is provided with an idling mechanism and has an idling angle δ. There is a possibility that the movable part 50 can freely operate in the range of the idling angle δ due to the vibration of the transformer or the like. This is because the free movement is restricted by the frictional force generated by the contact pressure when the movable contact sandwiches the fixed contact, that is, the fixed contact. Second, the flexible copper foil 61, the support 62, and the contact plate 66 are press-formed, and the contacts 64 can be manufactured by forging, so that they can be manufactured at low cost.

Next, the operation of the on-load tap changer configured as described above will be described with reference to FIGS.

FIG. 8A shows the state when the movable contact M1 is turned on. The resistance valve V2 is opened by the groove 4b and the main valve V1 is opened.
Is closed [FIG. 7 (b)]. FIG. 4B shows M1 → M2.
The M2 closing state in which the direction has been switched is shown, and the resistance valve V
2 is closed, and the main valve V1 is also closed [FIG. 7 (b)].

FIGS. 8C and 8D show operation sequence diagrams.

FIG. 8C shows the direction from M1 to M2. Since the main valve V1 and the resistance valve V2 are operated by the same cam as in the prior art, they are the same, but the changeover switch S operates with a delay of the idling angle δ. . Therefore, the time t1 is extended by that amount,
Conversely, time t3 decreases.

FIG. 8D shows the direction of M2 → M1 which is opposite to the above, and the operation is the same as described above. The time t1 is extended and the time t3 is decreased.

This operation will be described in more detail with reference to FIGS.

FIGS. 9 to 14 show the circuit configuration of the circuit shown in FIG.
2 shows an operation state of the mechanism unit corresponding to FIG. 7A is a circuit diagram corresponding to FIG. 7A, and FIG.
, The operation state of the main valve V1 and the resistance valve V2, (c) the operation state of the idling mechanism, (d) the state of the current collecting ring So of the changeover switch S, and (e) the contact state of the movable and fixed contacts. Is shown.

FIG. 9 shows an operation state at the tap T1, in which the main valve V1 is closed and the changeover switch S is set to the fixed contact S
1 has been selected.

When the drive shaft 2 rotates and the cam 4 starts rotating from such a state, the cam follower 21 approaches the inclined surface of the groove 4a as shown in FIG. 10, and the main valve V1 starts to open. At this time, the first coupling 10 of the idling mechanism 40 rotates, but the idling and the second coupling 51 remain stationary even when the idling reaches δ1.

Next, as shown in FIG.
When 1 moves along the inclined surface of the groove 4a, the main valve V1 opens, and when it further rotates and reaches the terminal end, the idling angle δ becomes zero (δ0 = 0), and the first coupling and the second coupling Are linked.

When the rotation continues and the cam follower 21 reaches a position near the center between the inclined surfaces of the groove 4a as shown in FIG. 12, the movable contact 60 separates from the fixed contact S1. At this time, the idling angle δ between the first coupling and the second coupling occurs in a direction opposite to the rotation direction.

Thereafter, as shown in FIG. 13, when the cam follower 21 reaches the vicinity of the rear inclined surface of the groove 4a, the movable contact 6
0 is supplied to the fixed contact S2. In this position, the main valve V
1 is still open.

When the movable contact 60 comes into complete contact with the fixed contact 60 as shown in FIG. 14, the main valve V1 is closed by the rear inclined surface of the groove 4a, and the operation state is at the tap T2. The movable contact 60 slightly rotates even after the main valve V1 is turned on, the stopper pin 9 comes into contact with one end of the operating range restraining groove 51b of the second coupling, and the operation ends, and the operation state is set by the tap T2.

The above description is the operation of switching from tap T1 to T2. However, the operation of switching from tap T2 to T1 is only the reverse operation, and the description is omitted here.

Next, the main part of the on-load tap changer according to the second embodiment of the present invention will be described with reference to FIGS. 15 to 21. The same parts as those in FIG.

In a large-capacity on-load tap changer,
Both the current and voltage to the vacuum valve increase, and the cutting duty becomes more severe. For this reason, if the time t1 from when the valve is shut down to when the changeover switch S is opened is further increased, the reliability is ensured. Two or more movable contacts 60 of the changeover switch S are used to cope with an increase in capacity. At the position where the vacuum valve V1 is turned on again, complete contact is made, and by maintaining a completely stationary state, it is possible to secure reliability as in the case of the above-mentioned time t1.

The second embodiment has been made from this point of view. As shown in FIG. 15, a configuration in which a pair of gear mechanisms and an intermittent gear mechanism are added to the above-mentioned idle mechanism 40 as an idle mechanism 100 is shown. It is assumed that.

In FIG. 15, reference numeral 10 denotes a first coupling similar to that shown in FIG. 1 attached to the drive shaft 2 by a connecting key 11, and reference numeral 101 denotes a drive shaft 2 which is close to the lower surface of the first coupling 10. With the attached second coupling, the second coupling 101 is a groove 101 for idling.
a, It is configured as a spur gear having an operating range restricting groove 101b.

Reference numeral 104 denotes the second coupling 101.
The intermittent gear attached to the insulating shaft 53 constituting the movable portion 50 of the changeover switch S located below the
04 has a drive groove 104a and a restraining groove 104b formed by cutting out a part thereof.

Reference numeral 102 denotes a spur gear with a driver supported on the lower surface of the plate 5 by a mounting pin 103 via a support member. The spur gear with a driver 102 includes a gear 102a meshing with the second coupling 101; And a driver 102b having a pin 102c that engages with a drive groove 104a of the intermittent gear 104 or a restraint groove that restrains free movement.

Next, the operation of the idling mechanism 40 of the on-load tap changer configured as described above will be described.

Now, the idling δ of the idling mechanism 40 is made as the first idling by the first coupling 10 and the second coupling 101, and the second idling is performed by the intermittent gear 104 and the spur gear 102 with a driver. Made. The second idling acts so as to be added to the first idling, and when the main valve V1 performs the closing operation, the movable contact 60 comes into complete contact and is kept stationary.

Here, the above operation will be described in detail with reference to FIGS.

FIGS. 16 to 21 show the circuit configuration of the circuit shown in FIG.
2 shows an operation state of the mechanism unit corresponding to FIG. 7A is a circuit diagram corresponding to FIG. 7A, and FIG.
, The operating state of the main valve V1 and the resistance valve V2, (c) the operating state of the idling mechanism, (d) the state of the current collecting ring So of the changeover switch S, and (e) the contact state of the movable and fixed contacts. Is shown.

FIG. 16 shows an operation state at the tap T1, in which the main valve V1 is closed and the resistance valve V2 is open. Further, the idling mechanism 100 is in a state where the first idling δ has in the operation direction. Further, the movable portion 5 of the changeover switch S
0 and the movable contact 60 are restricted grooves 104b of the intermittent gear 104.
And the driver 102b are restrained by engaging as shown.

To switch from the tap T1 to the tap T2 in such a state, when the drive shaft 2 is rotated, the cam and the first coupling 10 are rotated as shown in FIG. After opening, the slip δ becomes zero.

Then, the first coupling 10 engages with the second coupling 101 and starts rotating together. This rotation is transmitted to the driver 102b via the spur gear 102a, whereby the driver 102b rotates and reaches the drive groove 104a of the intermittent gear 104. During this time, the second idling operation is performed. At this time, the movable contact 60 is an intermittent gear 104
Does not work because it is bound by

Further, the first and second couplings 1
As shown in FIG. 19, when the pin 102c is rotated in a state in which 0, 101 is engaged, the pin 102c of the driver 102b
And rotates the intermittent gear 104 by a predetermined angle. At the same time, the movable contact 60 also rotates and the fixed contact S
2, the operation is again restricted by the restriction groove 104b, and the movable contact 60 is completely stopped.

In this position, the main valve V1 remains open. In the switching time at this time, the first idle time is defined as t1,
Assuming that the second idling time is α, after opening the main valve V1, t
1 + α is secured.

Next, when the pin 102c of the driver 102b is disengaged from the drive groove 104a, the gear with driver 102 performs the idling operation 0 as shown in FIG. On the other hand, when the cam follower 21 reaches the rear inclined surface of the cam 4, the main valve V1
Is about to start the throw operation. At this time, the movable contact 60 maintains the stationary state.

Then, as shown in FIG. 21, the main valve V1
Is closed after the closing operation, and the operation state is the tap T2. At this time, the driver 102b stops at the illustrated 180 ° rotation position (a position corresponding to FIG. 16), and ends the switching operation. On the other hand, the first idling δ is maintained at a position opposite to the current operation direction and is ready for the next operation.

The above description is the operation of switching from tap T1 to T2. However, the operation of switching from tap T2 to T1 is the reverse of the above operation, and a description thereof will be omitted.

As described above, according to the configurations described in the first and second embodiments of the present invention, the following effects can be obtained.

(1) The opening / closing mechanism of the vacuum valve includes a cam 4 for transmitting an opening / closing operation to the vacuum valve as a center, an operating portion on an outer periphery thereof, and a vacuum valve corresponding to each of the three phases directly below the cam 4 in a circumferential direction. An idler mechanism 40 that provides a certain time difference between the opening point of the vacuum valve and the release point of the changeover switch immediately below the cam 4 and a current collecting ring and a movable contact at a driven part of the idler mechanism. A changeover switch S for directly connecting the movable part having the switch and switching a fixed contact disposed outside the movable part is disposed, and each of the rotating parts is coaxially mounted on the drive shaft, so that dead space is effectively reduced. By making it possible to utilize and at the same time to give each component a composite function, the whole can be integrated into a compact.

(2) Since the idling mechanism 40 is provided between the cam 4 for opening and closing the vacuum valve and the movable portion 50 of the changeover switch S, the time t1 from the opening of the main valve V1 to the opening of the changeover switch S is reduced. The time required for shutoff can be secured, and the operation can be effectively utilized without expanding the entire operation range.

(3) The movable portion 50 has the drive shaft 2 as the center of rotation, and the sliding contact 70 from the power supply 71 of the main valve V1.
Is arranged in the center direction and is brought into contact with the current collecting ring 54, and the movable contact 60 is arranged below the current collecting ring 54 in the outer peripheral direction from the current collecting ring 54, so that the outer diameters of the insulating shaft 53 and the current collecting ring 54 are reduced. The mass of the movable contact 60 can be greatly reduced by using a copper foil to reduce the weight. further,
One stopper pin 9 is sufficient for restricting the operation range, and it can be manufactured at low cost.

(4) A load is applied to the cam followers 21 engaged with the cam grooves 4a and 4b in the rotation direction of the cam 4, and the guide rods 29 for guiding the bosses 20 driven in this operation direction are centered on the cam followers 21. By symmetrically arranging the two, the entire load can be received and there is no need to provide the holding table 110 or the like as in the conventional device, and no unnecessary force is applied to the movable contact.

(5) The vacuum force and the bellows force act on the movable contact 41 of the vacuum valve as a force to be drawn into the valve. When the contact is opened, it is pulled up with a force exceeding these forces. The collision with the fixed contact places a considerable burden on the connecting portion. In addition, since the movable contact must also have an energizing function, a copper material is used, but this portion is the mechanically weakest portion. In the embodiment of the above configuration, the opening / closing boss 24 is configured by a member having an energizing function,
The female screw is screwed into the male screw of the movable contact and fixed, and the energization function is configured as a female screw that receives the driving force with both the male screw and the female screw. It is possible and reliable.

[0117]

As described above, according to the present invention, it is possible to provide a highly reliable on-load tap changer capable of reducing the size and cost of the entire apparatus.

[Brief description of the drawings]

1A and 1B show a first embodiment of an on-load tap changer according to the present invention, in which FIG. 1A is a longitudinal sectional view, and FIGS. 1B and 1C show closing positions of switching contacts M1 and M2. FIG. 2 is a sectional view taken along the line BB of FIG.

2A is a sectional view taken along the line AA of FIG. 1, FIG. 2B is a sectional view taken along the line EE of FIG. 1A, and FIG. 2C is a sectional view taken along the line FF of FIG. .

FIG. 3 is a sectional view taken along the line CC of FIG. 1 of FIG. 1;

FIG. 4 is a sectional view taken along the line DD of FIG. 1 of FIG. 1;

FIGS. 5A and 5B show a movable portion of the changeover switch S according to the first embodiment, wherein FIG. 5A is a longitudinal sectional view and FIG.
GG sectional drawing of FIG.

6A and 6B show details of a movable contact of the changeover switch S according to the first embodiment, where FIG. 6A is a plan view in which two movable contacts are juxtaposed, FIG. 6B and FIG. ) Is a front view in the case of one piece, (e) and (f) are right and left side views, and (g) is a plan view.

FIG. 7A is a circuit diagram of a 1-resistance, 2-valve tap changer under load, and FIG. 7B is a circuit diagram illustrating a switching operation of the tap changer under load.

FIGS. 8A and 8B are diagrams for explaining the operation of the first embodiment, in which FIGS. 8A and 8B are operation explanatory diagrams mainly showing the positional relationship between a resistance valve and a cam; FIGS. () Is a diagram showing each switching direction and switching sequence of the tap switching contact.

9A and 9B are diagrams for explaining the operation of the mechanism corresponding to FIG. 7B in the first embodiment, and FIG.
Is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring, and (e) is movable. The contact state diagram of a fixed contact.

FIG. 10 is a view for explaining an operation of a mechanism corresponding to FIG. 7B in the first embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 11 is a view for explaining the operation of the mechanism section corresponding to FIG. 7B in the first embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 12 is a view for explaining the operation of the mechanism section corresponding to FIG. 7B in the first embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 13 is a view for explaining the operation of the mechanism section corresponding to FIG. 7B in the first embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 14 is a view for explaining the operation of the mechanism section corresponding to FIG. 7B in the first embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIGS. 15A and 15B show an idling mechanism in a second embodiment of the on-load tap changer according to the present invention, wherein FIG. 15A is a cross-sectional view, and FIG. 15B is an arrow view along line XX of FIG. Sectional view,
(C) is a sectional view taken along the line YY in (a).

FIG. 16 is a view for explaining the operation of the mechanism corresponding to FIG. 7B in the second embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 17 is a view for explaining the operation of the mechanism corresponding to FIG. 7 (b) in the second embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 18 is a view for explaining the operation of the mechanism section corresponding to FIG. 7B in the second embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 19 is a view for explaining the operation of the mechanism corresponding to FIG. 7 (b) in the second embodiment.
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 20 is a view for explaining the operation of the mechanism section corresponding to FIG. 7B in the second embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 21 is a view for explaining the operation of the mechanism section corresponding to FIG. 7B in the second embodiment;
(A) is a circuit diagram, (b) is an operation state diagram of a cam and a main and a resistance valve, (c) is an operation state diagram of an idling mechanism, (d) is a contact state diagram of a changeover switch and a current collecting ring (e). Is a contact state diagram of a movable and fixed contact.

FIG. 22A is a longitudinal sectional view showing a conventional load tap changer, and FIG. 22B is a sectional view taken along line XX in FIG.

23A and 23B show details of a connecting portion between the wipe rod and the movable contact in FIG. 22, where FIG. 23A is a plan view and FIG. 23B is a side view.

24A and 24B are diagrams for explaining the operation of a cam mechanism and a changeover switch for opening and closing a main valve and a resistance valve of a conventional on-load tap changer, and FIG. 24A illustrates the positional relationship between a main, resistance valve and a cam; FIG. 4B is a diagram illustrating the operation, and FIG. 4B is a diagram illustrating each switching direction and a switching sequence of a tap switching contact.

[Explanation of symbols]

 2. Drive shaft 4. Cam 9. Stopper pin 10. First coupling 20. Drive boss 21. Cam follower 24. 30 Opening / closing mechanism 40 Idling mechanism 41 Vacuum valve movable contact 42 Vacuum valve fixed contact 43 Male screw 44 Female screw 50 Movable part of changeover switch S 52 Second cup Ring 53: Insulated shaft 54 (So): Current collecting ring 60: Movable contact 61: Flexible copper foil 62: Support 64: Contact 65: Wipe spring 66: Contact plate 70: Slide contact 71, 72... Energizing table 100... Idling mechanism 101... Second coupling 102... Driver 104... Intermittent gear S1, S2... Fixed contact R.. ...... resistance valve

Claims (8)

[Claims] 1. A changeover switch having fixed contacts respectively connected to a plurality of taps provided in a transformer tap winding, and a movable contact for switching and connecting between the fixed contacts while sliding on a current collecting ring. A current limiting ring and two vacuum valves are connected in series between the current collecting ring and one adjacent tap of the changeover switch, and the two vacuum valves are provided. A load tap switch for switching the taps of the transformer tap windings by switching the taps of the transformer tap winding by switching the circulating current flowing between adjacent taps by opening / closing by a driving force applied from outside. A drive shaft rotated by force, a cam attached to the drive shaft to open and close the vacuum valve, and a vacuum disposed on an outer peripheral portion of the cam in parallel with the drive shaft. A vacuum valve opening / closing mechanism, which is provided directly in connection with a valve, and has an operating portion that operates in the axial direction by rotating the cam to open and close the vacuum valve, and a vacuum valve opening / closing mechanism provided below the cam. An idling mechanism having a driven part that provides a fixed time difference between an opening point and an opening point of the changeover switch; a movable part having the current collecting ring and a movable contact attached to the driven part of the idling mechanism; And a changeover switch in which a fixed contact disposed outside the movable portion is switched by a movable contact included in the movable portion, wherein the vacuum valve opening / closing mechanism is parallel to a drive shaft, and an idler mechanism and a movable portion of the changeover switch are provided. Is arranged coaxially with the drive shaft. 2. A vacuum valve opening / closing mechanism, wherein a cam is provided with two grooves in which appropriate portions in the circumferential direction are axially displaced.
A cam follower rotatably mounted on the drive boss is engaged with the groove, receives a load acting with the rotation of the cam at a symmetric position about the cam follower, and moves in a direction in which the cam groove is displaced. Two guide rods for guiding the driving boss are arranged, and the driving boss is engaged with an opening / closing boss that operates the driving boss at a predetermined interval. The opening / closing boss is fixed to a movable contact shaft of the vacuum valve by a screwing method. The on-load tap changer according to claim 1, wherein the load tap changer has an energizing function and an operating force transmitting function. 3. The idling mechanism engages a first coupling having a convex portion attached to a drive shaft and a convex portion of the first coupling to restrict a groove having an idling angle and an operating range. A second coupling having a restraining groove engaged with a stopper pin, wherein the second coupling is attached to a movable portion of a changeover switch, and the first coupling and the second coupling are And a switch that switches the operation range of the changeover switch to a predetermined range so that a certain time difference occurs between the cam that gives the opening and closing operation to the vacuum valve and the changeover switch. The on-load tap changer according to claim 1. 4. An idle mechanism according to claim 3, wherein said idle mechanism is a first idle mechanism, a pair of gear mechanisms directly connected to a second coupling of said idle mechanism, and an intermittent mechanism directly connected to said gear mechanism. A second idling mechanism configured to enable a changeover switch by the intermittent mechanism is provided, and the first idling mechanism and the second idling mechanism add a second idling to the first idling to form a vacuum valve. And a change-over switch, so that when the vacuum valve is turned on, the switching operation of the change-over switch is completed to be in a stationary state. The on-load tap changer according to claim 1. 5. A gear mechanism directly connected to the second coupling is a pair of spur gears, and an intermittent mechanism directly connected to the gear mechanism is a driver having one drive pin, one drive groove, and two restraints. 5. An on-load tap changer according to claim 4, comprising an intermittent gear having a groove. 6. A changeover switch mounted on a driven portion of an idling mechanism and rotatably held on a drive shaft, a current collecting ring mounted on an outer peripheral portion of the insulating shaft, and one end of the current collecting ring. A movable contact that alternately switches two fixed contacts provided on the outside of the other end of the current collecting ring at the other end of the current collecting ring The on-load tap changer according to claim 1, wherein the switch is mounted so as to be able to conduct electricity. 7. A current collecting ring mounted on an insulating shaft of a movable portion of a changeover switch is divided into three parts, each of which is arranged at a predetermined insulating distance, and one end of each of them is brought into sliding contact with a slide contact. 7. The on-load tap changer according to claim 6, wherein a movable contact for alternately switching a fixed contact is attached to the other end of the tap changer. 8. A movable contact is formed by attaching contacts to a pair of flexible copper foils respectively fixed to the front and back surfaces of a current collecting ring of a changeover switch, and the movable contacts are brought into contact so as to sandwich the fixed contact. 7. The on-load tap changer according to claim 6, wherein an energizing circuit is formed, and a contact structure capable of exerting self-limiting by a frictional force generated by a contact force of the wipe spring is provided.