JPH0124328B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power switching device that opens and closes an electric circuit.

1 to 4 show an example of a conventional power switchgear. In these figures, reference numeral 1 denotes a mounting base made of a metal steel plate, and the mounting base 1 is provided with a plurality of mounting holes 1a that are used when a power switchgear main body is already installed. A base 2 is made of an insulating material and is fixed to the mounting base 1 with screws 3. Reference numeral 4 denotes a fixed core made of laminated silicon steel plates. An operating coil 5 is attached to the fixed core 4, and a leaf spring 6 is disposed in the gap with the mounting base 1 as a cushioning material. 7
is a movable core disposed facing the fixed core 4, and when the operating coil 5 is energized, the fixed core 4
It is designed to be absorbed by. A cross bar 8 is made of an insulating material and is connected to the movable iron core 7 via a pin 9. Reference numeral 10 denotes a trip spring disposed between the crossbar 8 and the mounting base 1, which pushes up the crossbar 8 so that the main circuit of the power switching device is always opened. A movable contact 11 includes a movable contact 11a, which is inserted into a holding hole 8a provided in the cross bar 8, and is pressurized by a pressure spring 12. 13 is a contact 1 facing the movable contact 11 and the movable contact 11a.
3a, this fixed contact 13
is fixed to the terminal 15 by the screw 14, and
The aforementioned terminal 15 is fixed to the base 2 with screws 16 and 17. 13b is an arc runner and is electrically connected to the fixed contact 13, but it may be integrated with the fixed contact 13. 18 is a terminal screw connected to the main circuit electric wire, and is coupled to the terminal 15. An arc box 19 is made of an insulating material and is fixed to the base 2 with screws 20. The mark box 19 has a hole 19a for discharging arced gas to the outside, a ceiling part 19b, and a side plate 19.
It is composed of c. Reference numeral 21 is an arc extinguishing grid made of a magnetic material and has a shape as shown in FIG. 4, and 22 is a commutation electrode fixed to the ceiling 19b of the arc box 19. Movable contact 11a and fixed contact 13a
is formed in the arc extinguishing chamber.

Next, the opening/closing operation of this power switching device will be explained. When a voltage is applied to the operating coil 5 in the state where the main circuit shown in FIG. The above movable iron core 7
is attracted to the fixed iron core 4. At this time, the movable iron core 7
The crossbar 8 connected to the main circuit operates in the same manner, and the movable contact 11a of the movable contact 11 contacts the contact 13a of the fixed contact 13, and even when a predetermined pressure is applied by the pressure spring 12, the main circuit is closed. is closed. Next, when the operating coil 5 is demagnetized, the movable core 7 moves away from the fixed core 4 due to the biasing force of the tripping spring 10, and the crossbar 8 also moves in conjunction with the movable core 7. Therefore, the crossbar 8 returns to the state shown in FIG. 3, and the movable contact 11a of the movable contact 11 and the fixed contact 13a of the fixed contact 13 are separated. Upon this separation, an arc is generated between the movable contact 11a and the fixed contact 13a at a portion indicated by A in FIG. The movement of the arc from the time the arc occurs until the current is cut off will be explained using FIG. Since the arcing chamber in FIG. 1 is symmetrical, only one side of it is shown in FIG. Figure 5a shows fixed contact 1
3a and the movable contact 11a are shown in a closed state. When the fixed contact 13a and the movable contact 11a are opened while the operation coil 5 is energized, the fixed contact 13a and the movable contact 11
As shown in FIG. 5b, an arc 23 is generated between the points a and b. The contact separation distance increases over time until it reaches a certain distance. This arc 23 is driven and extended as shown in FIG. 5c by the current flowing through the movable contact 11 and the fixed contact 13 and the arc extinguishing grid 21, and one end of the arc 23 is connected to the fixed contact 13a as shown in FIG. 5d. surface is commutated to the arc runner 13b. Next, dielectric breakdown occurs between the tip of the arc 23 shown in FIG. 5d and the part shown by B of the arc runner 13b, and one end of the arc 23 is transferred to the part shown by B of the arc runner 13b shown in FIG. 5e. However, as shown in FIG. 5f, the other end of the arc 23 is transferred from the fixed contact 11a to the commutating electrode 22, and the arc 23 is attracted between the arc extinguishing grids 21 and extinguished. This extinction completes the current interruption.

In such power switchgear, arc 23
One end of the arc 23 tends to stick to the end of the fixed contact 13a, and the other end of the arc 23 tends to stick to the surface of the movable contact 11a, which increases the wear and tear of the expensive fixed contact 13a and the movable contact 11a, and also lengthens the arcing time. It has the disadvantage that the energy is large and it is not possible to supply or interrupt large currents.

The purpose of this invention is to reduce the wear and tear of expensive fixed contacts and movable contacts due to arcing, and to increase the shearing performance.

The power switchgear of the present invention is the same as the conventional power switchgear shown in FIGS. 1 to 4 except for the difference in the arc extinguishing chamber. Only the arc chamber portion is shown in FIG. FIG. 6 shows a state in which the movable contact 11a is fully opened. The commutating electrode 22 has a U end.
The tip end 22a of that part protrudes from the surface of the movable contact 11a, and the distance X ₁ from the surface of the arc runner 13b facing the surface of the movable contact 11a to the tip end 22a is the movable distance from the surface. It is set to be smaller than the distance _Y1 to the contact point 11a. FIG. 7 shows an enlarged view of the fixed contact 13 and the arc runner 13b. As can be seen from FIG. 7, the distance Y2 from the surface where the fixed contact 13a and the fixed contact 13 are joined to the surface opposite to the surface of the movable contact in the arc runner is the distance _Y2 from the joined surface to the surface of the fixed contact 13a. distance to x ₂
It is set to be larger.

FIG. 8 shows the movement of the arc from when it starts until it dies and breaks in the power switchgear according to the present invention. FIG. 8a shows a state in which the movable contact 11a and the movable contact 13a are closed. When the operation coil 5 is energized, the fixed contact 13a and the movable contact 11
When a is opened, an arc 23 is generated between the fixed contact 13a and the movable contact 11a as shown in FIG. 8b. The contact separation distance increases to a predetermined value over time. This arc 23 is driven by the current flowing through the movable contactor 11 and the fixed contactor 13, the magnetic commutating electrode 22, the arc extinguishing grid 21, etc., and _Y2 in FIG. 7 is replaced by _X2. Since it is configured to be larger, one end of the arc 23 is quickly transferred from the fixed contact 13a to the arc runner 13b as shown in FIG. 8c. Furthermore, since the configuration is such that X ₁ in Fig. 8 is smaller than Y ₁ , the arc 2
The other end of 3 is the movable contact 1 as shown in FIG. 8d.
It is rapidly transferred from 1a to the commutating electrode 22. Then, the arc 23 is driven and extended as shown in FIG. 8d by the current flowing through the arc runner 13b and the commutating electrode 22 and the arc extinguishing grid 21, and after passing through the state shown in FIG. 8e, it becomes as shown in FIG. 8f. The arc 23 is extinguished in the extinguishing grid 21 and the current is then interrupted.

In this way, in the power switchgear according to one implementation of the present invention, the time during which the arc 23 sticks to the surface of the movable contact 11a and the surface of the fixed contact 13a is shortened, so that the expensive movable contact 11a and the fixed contact 1
This makes it possible to reduce the consumption of 3a. Further, by shortening the sticking time, the arc time is shortened and the arc energy is reduced, so that it becomes possible to cut and hold a large current. Also, even if the arc box 19 is repeatedly opened and closed at short intervals,
Since damage to a is small, the switching life of the power switchgear can also be extended. Since the movable contact 11 is surrounded by a thermally poor conductor, if the current is repeatedly switched on and off at short time intervals, it will be heated by the arc 23 and reach a significantly high temperature, causing thermal damage to the crossbar 8 and causing the crossbar to break. 8 is broken, but
If the present invention is applied, the time during which one end of the arc 23 is stuck to the movable contact 11a is short, so the temperature rise of the movable contact can be reduced, and thermal damage to the crossbar 8 can be reduced. crossbar 8
can be made less likely to break. The fixed contact 13 and the arc runner 13b are shown in FIGS. 6 and 8.
Although it may be configured by joining the fixed contact 13 as shown in FIG. 9 and FIG. 9, the fixed contact 13
A fixed contact in which the arc runner 13b and the arc runner 13b are integrated may be used, or the arc runner 13b may be divided into two as shown in FIG. In the case of FIGS. 8 to 10, as in the case of FIG. 6, the time during which one end of the arc 23 stays on the surface of the fixed contact 13a can be shortened.

In the above embodiment, the present invention is applied to a power switchgear, that is, an electromagnetic contactor, which performs switching operations using a magnet. However, the present invention can also be applied to a wiring switch or a disconnector. An example of this is shown in FIG. FIG. 12 shows a situation where the fixed contact 13a and the movable contact 11a are separated. The movable contactor 11 is opened and closed by being rotated about the rotating shaft 24 by an operation mechanism (not shown). The movable contact 11 and commutation electrode 22 are made of stranded wire 26
The movable contact 11
are connected to the terminals by stranded wires 26. The arc first occurs between the movable contact 11a and the fixed contact 13a, one end of the arc 23 is transferred from the fixed contact 13a to the arc runner 13b, and finally the arc 23 is moved between the commutating electrode, the arc extinguishing grid, and the arc runner. The current is then cut off. In the power switchgear of the present invention, one end of the arc 23 is connected to the fixed contact 13.
Since the time that the fixed contact 13a and the movable contact 11a are stuck to the surface of the movable contact 11a can be shortened, the fixed contact 13a and the movable contact 11
It has the effect of reducing the consumption of a, but also has the effect of obtaining excellent welding performance because the shortening of the sticking time shortens the arc time and reduces the arc energy.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing a conventional power switchgear; Figure 2; Figure 3 is a side view and plan view of the device in Figure 1; Figure 4 is a configuration diagram showing the arc extinguishing grid in Figure 1; 5
The figures are explanatory diagrams showing the arc extinguishing chamber part and arc movement of a conventional power switchgear, FIGS. 6 and 7 are configuration diagrams showing an embodiment of the present invention, and FIG. Explanatory diagrams showing the arc extinguishing chamber portion and the movement of the arc, and FIGS. 9 to 12 are configuration diagrams showing other embodiments of the present invention, respectively. In the figure, 11 is a movable contact, 11a is a movable contact, 13 is a fixed contact, 13a is a fixed contact, 1
3b is an arc runner, 21 is an arc extinguishing grid, 22
is a commutating electrode, and 23 is an arc. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A fixed contact joined to a fixed contact, a movable contact joined to a movable contact and facing the fixed contact, an arc runner electrically connected to the fixed contact, and an arc generated at the movable contact. In a power switchgear equipped with a commutation electrode for transferring a leg, when both contacts are fully opened, the distance between the commutation electrode and the arc runner is shorter than the shortest distance between the movable contact and the arc runner. The movable contact, the arc runner, and the commutation electrode are arranged so that the shortest distance is small, and the distance from the surface where the fixed contact and the fixed contact are joined to the surface of the arc runner on the movable contact side is equal to the distance between the joint A power switching device configured such that the distance from the fixed contact point to the surface is greater than the distance from the fixed contact point to the surface.