JPH0345494B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power switching device with stable interrupting performance.

1 to 4 show an example of a conventional power switchgear. In the figure, a mounting base 1 made of a metal steel plate is provided with a plurality of mounting holes 1a for installing a power switchgear main body. A base 2 made of insulating material is fixed to the mount 1 by screws 3. An operating coil 5 is attached to a fixed core 4 on which silicon steel plates are laminated, and a leaf spring 6 is further provided as a cushioning material in the gap with the mounting base 1. A movable core 7 disposed opposite the fixed core 4 is attracted to the fixed core 4 when the coil 5 is energized. A cross bar 8 made of an insulating material is connected to a movable iron core 7 via a pin 9. A trip spring 10 disposed between the crossbar 8 and the mounting base 1 normally pushes up the crossbar 8 so that the main circuit of the power switchgear is opened. A movable contact 11 includes a movable contact 11 a, which is inserted into a holding hole 8 a of the cross bar 8 and is pressurized by a pressure spring 12 . Reference numeral 13 denotes a fixed contact including a movable contact 11 and a fixed contact 13a facing the movable contact 11a. 17.

Reference numeral 13b is an arc runner, which is electrically connected to the fixed contact 13, but may be integrated therewith. The terminal screw connected to the main circuit wire is terminal 15.
is combined with An arc box 19 made of an insulating material is fixed to the base 2 by screws 20. The arc 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. It is located inside the arc chamber.

Next, the opening/closing operation of this power switching device will be explained. When voltage is applied to the operating coil 5 with the main circuit open, magnetic flux is generated between the fixed core 4 and the movable core 7, and the movable core 7 attracts the fixed core 4 against the spring 10. and crossbar 8
operates in the same way, and the movable contact 11a is the fixed contact 13.
a, and the main circuit is closed by the pressure spring 12. Next, when the operating coil 5 is demagnetized, the movable contact 11a and the fixed contact 13a 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 with reference to FIG. Since the arc extinguishing chamber is bilaterally symmetrical, only one side of it is shown in FIG. Figure 5a shows both contacts 13a, 1
1a is in the closed state, and when both contacts are opened, the fifth
An arc 23 is generated as shown in Figure b. The contact separation distance increases over time up to a certain distance. This arc 23 is driven and extended as shown in Figure 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 fixed as shown in Figure 5d. It is transferred from the surface of the contact 13a to the portion indicated by A of the arc runner 13b. Next, dielectric breakdown occurs between the tip of the arc 23 shown in FIG.
The other end of the arc 23 is transferred from the movable contact 11a to the commutation electrode 22 as shown in FIG. 5f, and the arc 23 is attracted between the arc extinguishing grids 21. The arc is extinguished. This arc extinguishing completes the interruption.

In such a power switchgear, one end of the arc 23 tends to stick to the end of the fixed contact 13a, and the other end tends to stick to the surface of the movable contact 11a, which causes a lot of wear and tear on the expensive contacts 13a and 11a. The longer the arc time, the greater the arc energy.
It has the disadvantage of not being able to interrupt large currents.

Improved power switchgear have been invented to eliminate these drawbacks. The improved power switchgear is identical to the conventional version of FIGS. 1-4 except for the commutation electrodes and arc runners. An improved commutation electrode is shown in FIG. In Figure 6,
M is the notch part of the commutation electrode 22, and N is the commutation electrode 22.
The planar portion of the arc extinguishing grid 21 is configured to face the arc extinguishing grid 21 . As shown in FIG. 6, the movable contact 1
1a and the movable contact 11 are configured to fit into a notch M of the commutating electrode 22. That is, the commutation electrode 22 is configured to be located between both contacts when the separation distance between both contacts becomes maximum.

The arc runner 13b is joined to the U-shaped fixed contact ₁₃ by brazing, as _shown in FIGS. has been selected. The movement of the arc 23 in the improved power switchgear will be explained using FIG.

FIG. 8a shows a fixed contact 13a and a movable contact 11a.
indicates the closed state. When both contacts 13a and 11a open, an arc 2 is generated between both contacts as shown in FIG. 8b.
Generates 3. As the contact separation distance increases, both ends of the arc 23 are quickly transferred from both contacts to the commutating electrode 22 and the arc runner 13b, as shown in FIG. 8c. The arc 23 is connected to both contacts 11 and 13.
is driven by the current flowing through the Commutation electrode 22
A magnetic material is used as the material. Arc 2 when transferring
3 is caused by the current flowing through the movable contact 11 and the commutating electrode 22, which is a magnetic material, to the arc 23 shown in FIG. 6B.
A strong magnetic field shown by acts, and at this time a driving force F is generated, and the arc 23 moves from the movable contact 11a to the commutating electrode 2.
Transfer to 2. This transition is quickly performed by the driving force F and the shape of the commutating electrode. When a magnetic material is used as the arc runner 13b, the arc 2
3 is attracted to the arc runner 13b, and the arc 23
The leg of the arc runner 13b is quickly transferred from the fixed contact 13a to the arc runner 13b. Then, the arc 23 is driven and expanded as shown in FIG. 8 d by the current flowing through the commutating electrode 22 and the fixed contact 13, and passes through the state shown in FIG. 7 e, and becomes as shown in FIG. 8 f. , the arc is extinguished between the arc extinguishing grids. The interruption is completed by this arc extinguishing.

In this way, in the improved power switchgear,
One end of the arc is connected to the commutating electrode 22 from the movable contact 11a.
Since the transition to is performed very quickly, the wear of the movable contact 11a is reduced, the arc time is shortened, and the arc energy is reduced, so that the breaking performance is improved.

However, in this improved power switchgear, brazing is performed to join the arc runner 13b and the fixed contact 13. ) is around 60%, so arc runner 1
3b and the fixed contact 13 are not joined over the entire surface, and it is impossible to control the position of the non-joint part, so the non-joint part becomes a different place every time brazing is performed. If the non-bonded portion 24 is formed in the shaded area in FIG. 9, the current will flow in the direction shown by the arrow in FIG. 9 in the arc runner 13b via the fixed contact 13, and this will flow into the arc 23. 23 is driven in a direction in which arc extinguishing grid 21 is not present. Therefore, the improved power switchgear has the disadvantage that it becomes difficult to interrupt the arc current.

The present invention has been made to eliminate the above-mentioned drawbacks of the improved power switchgear, and has three sides of the fixed contact facing the sides of the arc runner,
By electrically insulating at least a portion of the arc runner near the contact from the fixed contact, the arc is always driven toward the arc extinguishing grid, and stable breaking performance can be obtained. Its features include a movable contact to which a movable contact is joined, a fixed contact that comes into contact with and separates from the movable contact, a first side to which this fixed contact is joined, and an anti-movable contact connected to this first side. the second extending to the side
A U-shaped fixed contact consisting of a side and a third side connected to the second side and provided in parallel with the first side, the second side or the third side of the fixed contact a first portion electrically connected to the side;
a second portion that is continuous with the first side of the fixed contact and is provided on the movable contact side with a space between the first side of the fixed contact and has a notch cut out from the side to allow vertical movement of the movable contact; In addition, an arc runner is provided, which includes a third portion extending from the second portion in a direction perpendicular to the side opposite to the fixed contact and being spaced apart from the fixed contact.

Embodiments of the present invention will be described with reference to FIGS. 10 to 12. In the configuration shown in FIG. 10, the tip of the arc runner 13b is made to hang down, and the vertical portion of the U-shaped fixed contact 13 is brazed to the part B in FIG. 10b. In this way, current flows through the arc runner 13b in the direction shown by the arrow in FIG. 10a, and the arc 23 is driven toward the arc extinguishing grid 21, resulting in stable breaking performance. Furthermore, the arc 23 moves in a short time to the arc runner surrounded on three sides, and the arc
When the arc runner 13b reaches the position shown in FIG. 1, the arc receives a large driving force and is driven faster due to the influence of the current flowing through the arc runner 13b, so that excellent interrupting performance can be obtained.

In the embodiment shown in FIG.
The tip of b is formed into a U-shaped cross section, and is brazed at a position c at the bottom of the U-shaped fixed contact 13. In the embodiment shown in FIG. 12, the fixed contact 13
D of the upper surface tip and the tip of the arc runner 13b
It is brazed at the position. Further, the electrical connection between the arc runner 13b and the fixed contact 13 is not by brazing, but by other bonding methods such as screwing,
This may be done by caulking, etc.

Although the present invention has been described as being applied to a power switching device that switches on and off current using a magnet, that is, an electromagnetic switch or an electromagnetic contactor, it can also be applied to other power switches such as molded circuit breakers. It can also be applied to

As described above, according to the present invention, the arc is transferred to the arc runner in a short time, and the arc is always driven to the arc extinguishing grid side by a large arc driving force, so the arc is driven quickly, and the interruption is stable and interrupted. A power switchgear with excellent performance can be obtained.

[Brief explanation of drawings]

Figures 1 to 4 show conventional power switchgear, with Figure 1 being a vertical front view and Figure 2 being a 1
FIG. 3 is a partial cross-sectional side view, FIG. 4 is a perspective view of the arc extinguishing grid, FIGS. A perspective view of a conventional improved commutating electrode, FIG. 7a is a plan view of a fixed contact and an arc runner, FIG. 7b is a sectional view taken along line A-A' in FIG. 7a, and FIGS. 8a to 8f are FIG. 9 is a diagram showing the movement of the arc of the improved switchgear, FIG. 9 is a diagram showing the non-bonded part and current flow in FIG. 7, and FIGS. 10a to 12 are diagrams showing embodiments of the present invention. FIG. 10a is a plan view of one embodiment, FIG. 10b is a sectional view taken along line A-A' in FIG. 10a,
FIG. 11 is a longitudinal sectional front view of the second embodiment, and FIG. 12 is a longitudinal sectional front view of the third embodiment. 11: Movable contact, 11a: Movable contact, 13:
Fixed contact, 13a: Fixed contact, 13b: Arc runner, 21: Arc extinguishing grid, 22: Commutation electrode,
23: Ark.

Claims (1)

[Claims] 1 A movable contact to which a movable contact is joined, a fixed contact that comes into contact with and separates from the movable contact, a first side to which the fixed contact is joined, and a first side connected to this first side and extending toward the side opposite to the movable contact. A U-shaped fixed contact consisting of a second side and a third side connected to the second side and provided in parallel with the first side, the second side or the third side of the fixed contact. The first side electrically connected to the side of
A notch portion is provided on the movable contact side with a space between the first portion and the first side of the fixed contact and allows the movable contact to move up and down. The arc runner includes an arc runner consisting of a missing second portion and a third portion extending from the second portion in a direction perpendicular to the side opposite to the fixed contact and being spaced apart from the movable contact. A power switchgear featuring: