JPH0447939Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a voltageless tap changer with an improved moving mechanism of a movable contact.

[Technical background of the invention and its problems]

Generally, when switching the system voltage on the primary or secondary side of a three-phase transformer, a series connection is used to connect the taps as shown in Figure 5A, and a tap-to-tap connection is used as shown in Figure B. There is a parallel connection that reduces the voltage by half.

In this case, the conventional voltageless tap changer
As shown in Figures A and B, a plurality of fixed contacts 1,
2, 3, and 4 are arranged at intervals on the same circumference in a predetermined arrangement order, and a movable contact 6 having a trapezoidal cross section attached to the shaft 5 is rotatably attached to the center of the contact. ing.

When connecting the tap changers with the above structure in series as shown in Figure 5A, two
Both the tap changers 7A and 7B have movable contacts 6
is switched to connect to the fixed contacts 2 and 3. In addition, when performing the parallel connection shown in FIG. 5B, one tap changer 7A connects the movable contact 6 to the fixed contact 1-3, and the other The tap changer 7B switches the movable contact 6 to the fixed contact 2-4 as shown in FIG. 7B.

Therefore, to switch between series and parallel connections,
Since two tap changers 7A, 7B are required for each phase, a total of six tap changers are required for a three-phase transformer.

For this reason, in a conventional three-phase transformer, six tap changers 7A to 7F are arranged in series as shown in FIG. It is designed to switch 6 units at the same time.

However, since the conventional type has six tap changers 7A to 7F arranged in series, the overall length is long, and especially in the case of a mobile transformer, it depends on the length in the width direction of the transformer tank loaded on the vehicle body. There is a problem that there are restrictions. For example, in the case of a transformer with a capacity of 10KVA, a conventional tap changer of 7A with six connected
~7F has a total length of about 1900mm, and if the capacity is larger than this, it is necessary to increase the distance between fixed terminals and the distance between adjacent tap changers for insulation reasons, and the total length becomes longer. There was a problem that the mobile transformer could not be mounted on the tower, and a countermeasure was requested.

Furthermore, in the conventional tap changer, while the movable contact 6 having a trapezoidal cross section rotates, the fixed contacts 1 to 4 are
Because of the structure in which they are fitted in sequence between the two, the operating mechanism is complicated and there are drawbacks such as the inability to perform smooth switching.

[Purpose of invention]

The present invention eliminates the above-mentioned drawbacks, and provides a voltage-free tap changer that has a simple and smooth operating mechanism, only requires one unit per phase, shortens the overall length, and can accommodate larger capacity. This is what we provide.

[Summary of the idea]

The present invention includes a shaft on which a plurality of cams are coaxially mounted, a plurality of fixed contacts arranged at intervals on a circumference parallel to the shaft and concentric with the shaft, and a plurality of fixed contacts corresponding to the cams. A plurality of rods are provided, each having a different mounting angle, a rod guide that supports the rods in a reciprocating manner, a roller that is provided at the base end of the rod and rolls while being guided by a cam, and a distal end of the rod. It is characterized by comprising a movable contact which is provided on the side and which simultaneously approaches and separates from an adjacent fixed contact.

[Example of idea]

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

1 and 2 show an embodiment of the present invention, in which the shaft 5 has a 6
The cams 8a to 8c are coaxially attached.
The first stage cams 8a, 8a, the third stage cam 8c,
Both discs 8c are mounted eccentrically on the shaft 5 by shifting the mounting angle by the required amount in the same direction, and the second stage cams 8b, 8b are 180° out of phase with the symmetrical mounting point of the cams 8a, 8c. It is eccentrically attached to the shaft 5 coaxially.

Fixed contacts 1, 2, 3, and 4 in the shape of round rods are arranged above the shaft 5, parallel to it, and at intervals on a concentric circumference with the shaft 5, and are made of an insulating plate. It passes through the upper part of the mounting base 9 and is supported by it.

Furthermore, as shown in FIG.
0... is provided to protrude laterally, and the rods 11a,
11b and 11c are supported in a reciprocating manner so that their mounting angles are different from each other.

Rollers 12 that roll in sliding contact with the outer peripheries of the cams 8a to 8c are attached to the lower ends of the rods 11a to 11c, respectively, and movable contacts 6a to 6a having trapezoidal cross sections are attached to the upper ends of the rods 11a to 11c. 6c are attached respectively.

Furthermore, the rods 11a to 11c are provided with a coil spring 13 for return between the rod guide 10 and the roller 12, and a coil spring 14 for pressing is provided between the rod guide 10 and the movable contacts 6a to 6c. Rod 11a-11
c is elastically supported by the rod guide 10 so as to be able to freely reciprocate.

In the tap changer having the above structure, for example, in the state shown in FIGS. 1 and 2, the rod 11b is pushed up to the top by the second stage cams 8b, 8b that have reached the top, and the rod 11b is attached to the tip. Movable contact 6
b and 6b contact the fixed contacts 2 and 3 at the same time and are electrically connected, resulting in a series connection as shown in FIG. 5A.

Further, when the shaft 5 is rotated, the cam 8b descends, and as the movable contact 6b separates from the fixed contacts 2 and 3, the cams 8a and 8c rise. When the cams 8a, 8c reach the top, the rods 11a, 11c rise accordingly, and the movable contact 6a attached to the tip becomes the fixed contact 1, 3, and the movable contact 6c becomes the fixed contact. The terminals 2 and 4 are contacted at the same time, resulting in the parallel connection state shown in FIG. 5B.

Therefore, one tap changer can switch between series and parallel connections for one phase, so in the case of a three-phase transformer, three tap changers can be connected in series, so even if the capacity is the same, By comparison, the total length is approximately
1100mm, which is approximately
It was possible to shorten the length by 800mm. As a result, it is possible to cope with an increase in the capacity of a mobile transformer, which is limited by the width of the vehicle body.

Moreover, the movable contacts 6a to 6c reciprocate up and down,
Since it approaches and separates perpendicularly to the fixed contacts 1 to 4,
The mechanism is simpler than the conventional rotary type, and the switching operation can be performed smoothly.

3 and 4 show another embodiment of the present invention, in which a return plate 15 is provided between the cams 8a and 8b, and this return plate 15 is as shown in FIG. It is formed of a rectangular insulating plate with round holes 16 formed therein.

The upper part of the return plate 15 is coaxially supported by a pin 17 that supports the rollers 12, 12. Further, a locking pin 18 is attached to both the cams 8a, 8a, passing through the lower round hole 16. Note that the return plates 15 are similarly attached to the other cams 8b, 8b, 8c, and 8c.

To explain the operation of the return plate 15, when the movable contact 6a, which has a trapezoidal cross section, is fitted between the fixed contacts 1 and 3 and is in a connected state, it is strongly pushed by the pressing coil spring 14. Therefore, even if a return coil spring 13 with low spring pressure is provided, it may not come out. At this time, when the cams 8a, 8a rotate and descend, the locking pin 18 connected to them is
The rod 11 is engaged with the inner periphery of the round hole 16 of No. 5, pushes down the return plate 15, and is connected to this with a pin 17.
Since a and 11a are also pulled down at the same time, cam 8
In conjunction with the rotation of a, 8a, the movable contact 6a,
It can be reliably separated from the fixed contacts 1 and 3.

In the above embodiment, six cams are installed coaxially and six movable contacts are installed correspondingly, but three or nine cams may be used.

Further, the roller attached to the rod is not limited to a structure in which it is guided by sliding on the outer periphery of the cam, but may be in a structure in which a cam groove is formed and the roller rolls within the cam groove.

[Effect of idea]

As explained above, according to the present invention, the operating mechanism has a simple structure consisting of a combination of a cam and a movable contact that reciprocates, and the movable contact moves up and down to be perpendicular to the fixed contact disposed above. Since the contact moves from one side to the other, the mechanism is simplified compared to the conventional structure in which the movable contact contacts while rotating, and there is no sliding wear between the contacts due to rotation, resulting in smooth rotation and excellent durability. , series and parallel connections for one phase can be performed with a single unit, and in the case of a three-phase transformer, the overall length can be significantly shortened and the capacity can be increased, and voltage-free tap switching is particularly effective for mobile transformers. You can get the equipment.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of a silent pressure tap changer according to an embodiment of the present invention, FIG. 2 is a side view of FIG. 1,
Fig. 3 is a longitudinal sectional front view of a voltageless tap changer according to another embodiment, Fig. 4 is a side view of Fig. 3, and Fig. 5A.
and B are connection diagrams, Figures 6A and B are explanatory diagrams of the operation of a conventional tap changer in series connection, and Figure 7
Figures A and B are explanatory diagrams of the operation of a conventional tap changer in parallel connection, and Fig. 8 is a front view showing a state in which six conventional tap changers used in a three-phase transformer are connected. 1, 2, 3, 4... Fixed contact, 5... Shaft, 6, 6a to 6c... Movable contact, 7A, 7B
...Tap changer, 8a-8c...Cam, 10...
... Rod guide, 11a-11c... Rod, 1
2...Roller, 13, 14...Coil spring, 15...Return plate, 16...Round hole, 17, 18
……pin.

Claims (1)

[Claims for Utility Model Registration] (1) A shaft in which a plurality of cams are installed coaxially at intervals, and a plurality of cams arranged on a concentric circumference parallel to the shaft and spaced apart above the cams. A plurality of rods are attached radially at different angles between the fixed contact and the above fixed contact corresponding to the cam, and these rods are supported so as to be able to reciprocate in the vertical direction. a rod guide provided at the lower end of the rod, which rolls while being guided by a cam, and a movable contact provided at the upper end of the rod, which simultaneously approaches and separates from the adjacent fixed contact. A voltage-free tap changer characterized by: (2) A utility model according to claim 1, characterized in that the rod is elastically supported by a rod guide with a spring, and the roller at the lower end of the rod and the cam are connected by a return plate. Voltage tap changer.