JPS6072131A - Swtich - 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 [Technical Field of the Invention] The present invention relates to a switch such as a circuit breaker that has improved ability to interrupt electrical circuits.

[Prior Art] Figures 1 to 3 are cross-sectional views showing conventional circuit breakers.
Each shows a different operating state. In the figure,
(1) is cover, (2) is pace, force/<' -(1
) and the base (2) constitute a housing (3). (
4) is a fixed contact, which has a fixed conductor (5), has a fixed contact (6) at one end, and an outer conductor (not shown) at the other end.
It has a terminal section so that it can be connected to. (7) is a movable contact, which has a movable conductor (8), and has at one end a movable contact (9) facing the fixed contact (6). (10
) is a movable contact device, and (11) is a movable contact arm, which is fixed to a crossbar (12) and is opened and closed when each pole is spaced. (13) is an arc extinguishing chamber, and an arc extinguishing plate (14) is held by a side plate (15). (16) is a toggle link mechanism, which is composed of an upper link (17) and a lower link (18). One end of the upper link (17) is connected to the fredl (19), and the other end is connected to one end of the lower link'' (18) by shafts (20) and (21), respectively. The other end is the movable contact device (l
It is connected to the movable arm (11) of O). (22) is the raising/lowering type operation/handle, (23) is the operating spring, which connects the shaft (21) of the toggle link mechanism (16) with the operation handle (
22). (24) and (25) are thermal and electromagnetic trip mechanisms, respectively, and when activated, bimetal (26) and movable iron core (27) are activated.
) to rotate the trip bar (28) counterclockwise. (29) is a latch whose one end is locked to the trip bar (28) and the other end is locked to the fredle (19).

If the operating handle (22) is tilted to the closing position with the fredle (19) locked to the latch (29), the toggle link mechanism (16) will extend and the shaft (21) will move to the fredle (19).
The movable contact (9) is joined to the fixed contact (6). This state is shown in FIG.

Next, if you move the operation/handle (22) to the open position,
The toggle link mechanism (16) is bent, the movable contact (9) is separated from the fixed contact (6), and the I+) movable arm (11) is locked to the fredl shaft (30). This state is shown in FIG.

In addition, if an overcurrent flows through one circuit in the open state shown in Fig. 1 above, the thermal tripping mechanism (24) or the electromagnetic tripping mechanism (25) is activated, and the fredle (19) and latch (29) are activated. The attachment is released, the fredle (19) rotates clockwise around the fredle shaft (30), and is locked to the stopper shaft (31). At this time, since the connection point between the fredle (19) and the upper link (17) crosses the line of action of the actuation spring (23), the toggle link mechanism (16) is bent by the spring force of the actuation spring (23), and the Talosper (12
) for automatic shutoff in conjunction with each pole. This state is shown in FIG.

Next, the behavior of the arc that occurs when the circuit breaker cuts off the current will be explained.

Now, when the movable contact (9) and the fixed contact (6) are in contact, the power is transferred from the power source side to the fixed conductor (5).
), fixed contact (6), movable contact (9) and movable conductor (
8) and is sequentially supplied to the load side. In this state, when a large current such as a short circuit current flows through this circuit, the movable contact (9) is separated from the fixed contact (6) as described above. At this time, an arc (32) is generated between the fixed and movable contacts (9), and the fixed and movable contacts (6),
(9) An arc voltage is generated between the two. This arc voltage increases as the separation distance of the movable contact (9) from the fixed contact (6) increases, and at the same time the arc voltage (3
2) is attracted by the magnetic force and extends in the direction of the arc-extinguishing plate (14), so it further rises. In this way, the arc current reaches a current zero point, the arc is extinguished, and the interruption is completed.

However, conventionally, in this breaking operation, the arc (32) does not move easily beyond the contacts (6) and (9), and the legs of the arc (32) always exist above the contacts (6) and (9). Therefore, not only are the contacts (6) and (9) significantly worn out, but the arc (32) is not easily cooled because it is difficult to contact the arc extinguishing plate (14), and sufficient arc extinguishing ability at the zero current point is not achieved. I couldn't.

FIG. 4 shows an arc extinguishing chamber in a conventional switch.

That is, in the conventional type, the arc extinguishing chamber is formed by stacking a plurality of arc extinguishing plates (14) of the same shape.

Figure 5 shows the arc (32) in the arc extinguishing chamber and the arc extinguishing plate (
14). In the breaking operation, when the movable conductor (8) opens and its length increases, the arc (32) receives an attractive force from the arc extinguishing plate (14).
When the current is large, no spot is formed on the surface of the arc-extinguishing plate (14), and the arc voltage does not rise much. Therefore, the sixth
As shown in the figure, the arc voltage V increases as the current increases, but decreases as the current I decreases.

This is because the arc (32) is not long enough and the arc (32) is not long enough.
32) is not divided by the arc extinguishing plate (14). As described above, conventional switches have a drawback in that the arc voltage at the zero current point is low and sufficient breaking performance cannot be obtained.

[Summary of the Invention] The present invention has been made to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide a switch with low contact wear and excellent breaking performance.

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

FIGS. 7(a) and 7(b) show the arc-extinguishing plate (14) in this invention.
), the difference from the conventional one is that the arc-extinguishing plate (14)
The reason is that an arc transition portion (141) having a constant area is formed integrally with the arc extinguishing plate (14), making an angle X with the plane of

FIG. 8 shows the state in which high-temperature steam (32a) is ejected by the arc emitted from the tip end face of the movable conductor (8,). According to experimental observations, this high-temperature steam is particularly strongly emitted into the space created by the straight line E, which forms an angle of approximately 30° with respect to the normal n to the tip surface of the movable conductor (8). This high temperature steam constitutes the main path of the arc current, generally called the arc core. In Figure 8, the arc transition part (1) of the arc extinguishing plate (14) is shown.
41) is located within the range of this jet of high-temperature steam, and under such circumstances, the legs of the arc (32) are likely to form a spot at the arc transition portion (141). FIG. 9 shows how spots are actually formed.

By the way, the inventors have discovered that in order to ensure that the spot of the arc (32) is formed at the arc transition portion (141), the tip surface (81) of the movable conductor (8) and the arc transition portion (141) must be
) was found to be an important factor in the angle θ with the plane.

That is, as shown in FIG. 10, the arc extinguishing plate (14) is
The arc transition portion (141) was formed on the arc extinguishing plate (14) at the top of the stack, and the relationship between θ and arc voltage was investigated by changing 0 in the range of 0 to 90'. The opening distance of the movable conductor (8) was 17 mm, and the current applied was 20 KA due to a short circuit.

FIG. 11 shows the experimental results at this time.

The vertical axis is the sustaining voltage VO at the current zero point, and the level of this sustaining voltage vO depends on whether the leg of the arc (32) is at the arc transition part (1
41) serves as a criterion for determining whether or not a spot has been formed.

That is, the legs of the arc (32) are at the arc transition part (141
), the arc voltage rises all at once to about 400V, and always maintains this value until the current zero point.

As is clear from FIG. 11, the occurrence or non-occurrence of the arc transfer phenomenon is determined when θ is approximately 45°. That is, if O0≦0≦45°, the legs of the arc (32) can reliably form a spot at the arc transition portion (141). However, when 0 exceeds 45°, the arc (3
2) Metastasis becomes rapidly difficult. This means that the current flowing through the arc extinguishing plate (14) shown in Figure 9 by the arc (32)
This is thought to be due to the fact that it acts as an electromagnetic repulsive force.

FIG. 12 is a perspective view of the arc extinguishing chamber in the embodiment of the present invention, and FIG. 13 is a front view thereof. In FIG. 13, θ is set to O0≦θ≦45° for the above reason. As shown in the figure, the arc transition part (14
When an arc spot is formed in step 1), an arc spot is formed in series between the plurality of arc extinguishing plates (14), thereby significantly increasing the arc voltage. Of course, since the arc (32) has moved to the arc transition portion (141), its length has also increased.

Therefore, the arc voltage V at this time, as shown in FIG.
It is uruchino that maintains 0. As a result, the current in the second half is significantly limited by the high voltage, and the breaking performance at the current zero point is also greatly improved.

Note that, in view of its original purpose, the arc transition part (141) in the above embodiment contacts the tip surface of the movable contact (7) at least once while the movable contact (7) moves to the final opening position. Of course, they must be in a position where they can face each other.

FIG. 15 shows another embodiment of the present invention, in which a movable contact (9
) around the contact tip surface (81) side except for the insulating material (40
) is arranged. With such a structure, the legs of the arc (32) will not expand anywhere other than the tip surface (81), so if used in conjunction with the above-mentioned arc transition part (141), the legs of the arc (32) will quickly expand. It is even more effective because it can move to the distal end surface (81) and transfer to the transition area (141).

Furthermore, since the tip surface (81) of the movable contactor (7) and the plane of the arc transition portion (141) only need to face each other at an angle of 45° or less, the movable conductor (8)
41) may have a relationship as shown in FIG.

Furthermore, the shape of the arc transition part (141) is not limited to the above embodiments, and for example, the shape shown in FIGS.
Various types as shown in the figure are possible. Note that the fixed contact (4) may be a so-called repulsive contact that separates from the movable contact (7) in response to an electromagnetic repulsion force caused by an energized current. Furthermore, although the above embodiments have been explained using a switch as an example, the present invention can be applied to an electromagnetic switch, a current limiter, etc. that generates an arc within a housing, in addition to the switch of the present invention.

[Effects of the Invention] As explained below, according to the present invention, an arc transition portion is formed on the arc extinguishing plate, and while the movable contact moves to the final opening position, the tip surface of the movable contact is Since the arc and the plane of the arc transition part are arranged to face each other at an angle of 45° or less, the arc can be reliably transferred to the arc extinguishing plate, and the arc voltage can be increased to improve the breaking performance. , it is possible to provide a switch that can also reduce wear and tear on contacts.

[Brief explanation of the drawing]

Figures 1 to 3 are sectional views showing different operating states of a conventional circuit breaker, Figure 4 is a perspective view of a conventional arc extinguishing chamber, Figure 5 is a front view thereof, and Figure 6 is a A diagram showing temporal changes in arc voltage and arc current, FIG. 7(a) is a perspective view of an arc extinguishing plate in an embodiment of the present invention, FIG. 7(b)
is a front view of the same, FIG. 8 is a diagram showing how high-temperature steam is ejected by the arc, FIG. 9 is a diagram showing the state when an arc spot is formed at the arc transition part, and FIG. 10 is a diagram showing details of this invention. 11 is a diagram showing the relationship between θ and arc voltage in FIG. 10, FIG. 12 is a perspective view of the arc extinguishing chamber in an embodiment of the present invention, and FIG. 13 is a front view thereof. Fig. 14 is a diagram showing temporal changes in arc voltage and arc current, Fig. 15 (IIL) is a front view showing another embodiment of the present invention, Fig. 15 (b) is a plan view thereof, and Fig. 16 17 is a front view showing another embodiment of the invention, and FIGS. 17 and 18 are perspective views showing other embodiments of the invention. (3)...Housing, 4)...Fixed contact, (6).
...Fixed contact, (7)...Movable contact, (9)...
Movable contact, (14)... Arc extinguishing plate, (32)... Arc, (81) Fist/tip surface, (141)... Arc transition part. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A fixed contact having a fixed contact, a movable contact having a movable contact that comes into contact with and separates from the fixed contact, and an arc extinguishing plate for extinguishing the arc generated between both the above contacts in a housing. In the switch housed in the switch, an arc transition portion is formed on the arc extinguishing plate, and while the movable contact moves to the final opening position, the tip surface of the movable contact and the plane of the arc transition portion A switch characterized in that the switch faces each other at an angle of less than °. (2) The switch according to claim 1, wherein an insulating material is arranged around the movable contact except for the tip side of the movable contact.