JPS5927419A - Device for switching vacuum switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum switch opening/closing device, and particularly to a fixed electrode support structure thereof.

It is generally said that the weakest point mechanically in a vacuum switch is the bellows that allows the electrodes to move while keeping them airtight. Since the bellows is very weak against impact forces, various methods have been taken in switching devices using vacuum switches to reduce this impact force. One type of switchgear that takes such measures to reduce impact force is a switchgear shown in FIG. 1 in which the electrodes of a vacuum switch are fixed via an elastic body, that is, a leaf spring.

As shown in FIG. 1, the vacuum switch includes a vacuum switch, a fixed electrode, and a movable electrode 3 that comes into contact with and separates from the vacuum switch, and the movable electrode 3 is connected to the vacuum container by a bellows V. The fixed electrode is held by a plate spring 6, the plate spring has a fixed end 7, and the central part is connected to the fixed electrode by a mounting bolt.

In the conventional switching device configured in this way, when the movable electrode 3 starts the opening operation, the fixed electrode receives the vacuum self-closing force via the vacuum container S and the resultant force of the force required to displace the bellows. (hereinafter referred to as the operating force of the vacuum switch) is applied,
The leaf spring plate is displaced to a position where its spring force and this operating force are balanced, and only then does the separation of the two electrodes begin. On the other hand, as is well known, bonding between molecules takes place in a vacuum with a much smaller pressure than in other atmospheres, so in the case of vacuum switches, welding of electrodes is much more difficult than with other switching contacts. Likely to happen.

In the switchgear shown in Fig. 1, when electrode welding occurs, leaf spring A is displaced to a position where it obtains a spring force commensurate with the welding force of the electrodes in addition to the above operating force, and the point at which both electrodes separate is further Unfortunately, if the hole is so large that the welding force of the contact reaches the plastic deformation region of the leaf spring, not only will the opening point shift, but the opening distance will become smaller. I fall into this. Especially like a tap changer on load, contact 11? In electrical equipment in which the I closing point is functionally important, the delay in the opening point and the shift in the opening/closing point as described above pose a major problem.

Figure 1 shows seven examples of on-load tap changer circuit systems.
// is the transformer tap winding, lλ is the odd-numbered side main arc contact,
13 is a resistance contact, /l is an even-numbered main arc contact, l is a current limiting resistor, 16 is a tap in use, and /7 is a tap to be used next.

Figure 3 shows the switching sequence of each contact in Figure 2, the white line represents the ON period, and T is from the opening (OFF) of the odd-numbered main arc contact/2 to the closing (ohh) of the even-numbered main arc contact/G.
m) or vice versa. When the load requires a switching sequence as shown in Figure 3, if a delay in the opening timing as described above occurs in the tap changer, the time T in Figure 3 will be shortened. If a situation where T becomes shorter than the arc time occurs, the worst accident for the on-load tap changer will occur, which is a short circuit between taps. Furthermore, when the plate genera undergoes plastic deformation, the opening distance between the electrodes decreases, and the device no longer has a predetermined withstand voltage.

This invention was made in view of the above-mentioned drawbacks, and aims to provide a vacuum switch opening/closing device having stable switching pole points without losing the conventional buffering capacity. The switch opening/closing device is characterized in that it includes a stopper that restricts the operation of the elastic body only when the switch is opened.

The invention will now be described with reference to illustrative embodiments.

As shown in FIG. 1, in the present invention, a stopper (J) 7 is provided to prevent the displacement of the elastic body, that is, the leaf spring A, and the stopper is positioned in contact with the side of the leaf spring 6 that is displaced when the contact is opened. The span of the plate spring t is L, and a hole of size 1 is provided in the stopper, and 1 is sized to have a gap between it and the fixed electrode to the extent that its movement is not restricted. The structure other than the stopper 7 is the same as the conventional one shown in FIG.

In the switchgear configured as shown in Fig. 1, the movable electrode 3
When starts the opening operation, the (L-1) part of the leaf spring O is prevented from displacing by the stopper de, so the leaf spring with a span of L becomes a leaf spring with a span of 1, and the spring constant is increases. In other words, the rigidity of the leaf spring O is high (because of this, even if the above-mentioned operating force is applied to the fixed electrode, the displacement of the leaf spring O is not only much smaller than before, but also the distance between the electrodes is Even when welded, the plate spring 6 is less likely to undergo plastic deformation, and the opening point of the vacuum switch is always opened and closed at a stable position without delay.On the other hand, when closing, the stopper 9 is held at the plate spring 6. Since no restrictions are placed on the operation of the buffer, the conventional buffering capacity is not impaired.

(+') Therefore, by configuring as in the present invention, a vacuum switch opening/closing device having the following effects can be obtained.

(1) It has a stable switching and closing pole operating point.

(g) Even if welding of the contacts occurs, plastic deformation is less likely to occur in the elastic body, which reduces the possibility that the opening distance between the electrodes will become smaller.

(3) It has sufficient buffering capacity against the impact force when the pole is closed.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view schematically showing seven examples of conventional vacuum switch opening/closing devices, Figure 1 is a circuit diagram of an on-load tap changer in which the vacuum switch opening/closing device is used, and Figure 3 is the first diagram. Figure V is a sectional view similar to Figure 1 showing an embodiment of the vacuum switch opening/closing device according to the present invention. L... Vacuum switch, C... Fixed electrode, 3... Movable electrode, G... Bellows, 5... Vacuum container, 6... Leaf spring, Ri... Fixed end, Z... Mounting bolt, De... Stotsuba, //
...Transformer tap winding, 12...Odd number side main arc contact,
No. 3: Resistance contact, /G: Even number side main arc contact, 1g
...Current limiting resistor, 16...Tap in use, 17...Tag to be used next. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Makoto Kuzuno - (7) Figure 1, Figure 3, Figure 2, Figure 4.

Claims (1)

[Claims] A vacuum switch opening/closing device in which an electrode of the vacuum switch is fixed via an elastic body includes a stopper that does not restrict the operation of the elastic body at all when the vacuum switch is closed, but restricts the operation only when the vacuum switch is open. A vacuum switch opening/closing device characterized by: