JPS5847630Y2 - Vacuum cutter - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a vacuum breaker.

Generally, a vacuum breaker is constructed by arranging a fixed electrode and a movable electrode facing each other in a vacuum container, and current is applied by moving the movable electrode toward and away from the fixed electrode.

It is shutting off.

However, when breaking, an arc is generated between the electrodes, and if the breaking current is large, this arc receives electromagnetic force in the direction of the electrode's outer circumference due to the interaction between the magnetic field generated by the arc itself and the magnetic field created by the external circuit, and the arc It leans toward the outer periphery and locally heats that area, generating a large amount of metal vapor.

For this reason, metal vapor remains between the electrodes after the current reaches zero, delaying insulation recovery and reducing the breaking ability.

Conventionally, as a countermeasure against this problem, applying an axial magnetic field to the arc has been carried out.

An example is shown in FIG.

In the figure, 1 is an insulating tube, 2 and 3 are end plates attached to both ends of the insulating tube 1, 4 is a fixed electrode rod inserted into the end plate 2,
5 is a fixed electrode rod inserted into the end plate 3 and attached to the end plate 3 via a bellows 6; 7 and 8 are electrode rods 4, respectively;
, 5, with a fixed electrode and a movable electrode attached to the tip.
The movable electrode 8 is a coil electrode having a base 9a attached to the tip of the movable electrode rod 5, and a coil portion 9b that extends from the base 9a in a coil shape to form a one-turn coil, and the base 9a is made of a high resistance material such as stainless steel. 10, and a connecting conductor 12 that connects the tip of the coil portion 9b to the contact electrode 11. Similarly, the fixed electrode 7 includes a coil electrode 13, a high resistance material 14. It is composed of a contact electrode 15 and a connecting conductor 16.

In this vacuum breaker, the breaking current at the time of breaking is, for example, movable electrode rod 5 - coil electrode 9 - connecting conductor 12 - contact electrode 1
1-Arc-contact electrode 15-Connecting conductor 16-Coil electrode 13-Fixed electrode rod 4 flow, each coil electrode 9,1
3 generates an axial magnetic field.

For this reason, charged particles such as electrons and ions carrying the arc current are captured by this magnetic field, preventing the concentration of the arc, and each contact electrode 11.15 is not locally heated, so a large amount of metal vapor is generated. This does not occur, and the insulation recovery after the current zero point is accelerated, and the breaking capacity is improved.

However, in the above-mentioned vacuum breaker, the coil portion 9b is long because it forms a one-turn coil.
Since current always flows through b in the closed state, heat loss is large, and a vacuum breaker for large current ratings has the disadvantage of temperature rise.

Also, in the past, there is a coil electrode 17 of a shunt type as shown in FIG.

In this case, the coil electrode 17 has four coil parts 1 forming a two-turn coil extending in a coil shape from the base part 17a.
7b, and the tip of each coil portion 17b is connected to a contact electrode via a connecting conductor 18, respectively.

In this example, the current flowing from the electrode rod to the base 17a is divided into each coil part 17b, so the current flowing through each coil part 17b is equal to one part of the total current, and heat loss is small, but the axial magnetic field is large. It has the disadvantage that it becomes smaller.

In consideration of the above points, it is an object of the present invention to provide a vacuum breaker that can generate a relatively large axial magnetic field, has low heat loss, and has a simple structure.

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

In FIG. 3, reference numeral 19 denotes a coil portion 19 whose base portion 19 b is attached to the tip of the electrode rod 20 and which is attached to the base portion 19 a and extends into a coil to form a one-turn coil.
Coil electrodes 21 to 24 each have a coil part 1
The diameter of each of the connecting conductors 21 to 24 is increased as the connection conductor is erected at a position closer to the tip of the coil portion 19b.

Reference numeral 25 denotes a contact electrode attached to the tip of each of the connecting conductors 21 to 24, and the contact electrode 25 has four pieces 25 attached to its periphery.
Slits (25) and 25e are provided radially to partition into sections a to 25d and to suppress eddy currents.

In this vacuum breaker, for example, current flows from the electrode rod 20 to the coil portion 19b via the base portion 19a.

The current then flows through the connecting conductors 21 to 23 to the respective parts 25b.
25d, the current flowing through the coil part 19b gradually decreases and finally flows through the connecting conductor 24 to the part 25a.

At this time, if the connecting conductors 21 to 24 have the same diameter, most of the current will flow through the connecting conductor 21, and almost no current will flow through the connecting conductor 24.

However, the closer the connecting conductors 21 to 24 are installed upright to the base 19a of the coil portion 19b, the smaller the diameter, and therefore the higher the resistance, and the current flowing through each of the connecting conductors 21 to 24 is averaged. be done.

Therefore, compared to the conventional one shown in FIG. 1, the current flowing through the coil portion 19b gradually decreases, resulting in smaller heat loss. However, since some current flows through the coil portion 19b for one turn, the axial magnetic field is not large enough. It doesn't get smaller.

Furthermore, although the heat loss is slightly greater than that of the shunt type shown in FIG. 2, the axial magnetic field can be significantly increased.

Note that the current flows in the opposite direction, that is, from the contact electrode 25 to each connection conductor 21.
24 to the coil electrode 19, the current flows through each connecting conductor 21 to 24 in an average manner, so that the same effect as described above is obtained.

Further, the electrode structure shown in FIG. 3 can be applied to both or only one of fixed and movable electrodes.

As described above, in the present invention, a plurality of connecting conductors are provided between the coil electrode and the contact electrode that form a one-turn coil, and the diameter of each connecting conductor increases as it approaches the tip of the coil electrode. .

Therefore, the current does not flow only to the connecting conductor near the base of the coil electrode, but flows in an average manner to each connecting conductor.

Therefore, there is also a current that flows through the coil electrode for one turn, and the magnitude of the axial magnetic field does not decrease much compared to the conventional one-turn type coil electrode, and it has a large blocking ability.

Furthermore, since the current flowing through the coil electrodes is gradually reduced by being shunted to each connected conductor, heat loss is reduced, and even in a vacuum breaker for a large rated current, the disadvantage of temperature rise is less likely to occur.

In addition, since each connecting conductor also serves as a spacer between the coil electrode and the contact electrode, there is no need to provide a special spacer that requires high resistance materials as in the prior art, and the structure is simplified.

[Brief explanation of the drawing]

Figures 1A and B are a longitudinal sectional front view and a perspective view of a coil electrode of a conventional vacuum breaker, respectively, Figure 2 is a perspective view of another conventional vacuum breaker, and Figures 3A and B are respectively related to the present invention. FIG. 2 is a front view and an exploded perspective view of an electrode portion of such a vacuum breaker. 1... Insulating cylinder, 2, 3... End plate, 6.
...Bellows, 19...Coil electrode, 2
0... Electrode rod, 21-24... Connection conductor, 25... Contact electrode.

Claims (1)

[Scope of utility model registration request] In a vacuum breaker in which a pair of electrodes are arranged facing each other so as to be able to come into contact with and be separated from them through electrode rods in a vacuum container, a coil electrode that is attached to the tip of the electrode rod and forms a one-turn coil that generates an axial magnetic field; At least one of the plurality of connection conductors that are erected on the coil electrode and whose diameter increases as the erected position is closer to the tip of the coil electrode, and a contact electrode attached to the tip of each connection conductor. A vacuum breaker characterized by comprising: