JPS6072135A - 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 [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 a cover, (2) is a base, and the cover (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 has a terminal portion at the other end to be connected to an external conductor (not shown). ing. (7) is or! !
The IJ contact has a movable conductor (8), and one end thereof has a movable contact (9) facing a fixed contact (6). (
io) is a movable contact device, and IIf (11) is fixed to a movable contact arm crossbar (12) and is opened and closed when each pole is spaced. (13) is the arc extinguishing chamber, and the arc extinguishing plate (
14) is held by the side plate (15). (16)
is a toggle link mechanism, with the upper link (17) and lower link (
18). One end of the upper link (17) is connected to the cradle (19), and the other end is connected to one end of the lower link (18) by shafts (20) and (21), respectively. The other end of the lower link (18) is connected to the movable arm (11) of the movable contact device (lO). (
22) is a tilting operation handle, (23) is an operating spring,
- It is stretched between the shaft (21) of the toggle link mechanism (16) and the operation handle (22). (24), (
25) are thermal and electromagnetic trip mechanisms, respectively;
During operation, the tri-tube bar (28) is rotated counterclockwise by the bimetal (26) and movable iron core (27), respectively. (29) is a latch whose one end is locked to the trip/<-(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, when the operation handle (22) is tilted to the open position, the toggle link mechanism (16) is bent, the movable contact (9) is separated from the fixed contact (6), and the UL movable arm (11) is moved to the freddle position. It is locked to the shaft (30). This state is shown in FIG.

In addition, if an overcurrent flows through the circuit in the open state shown in Fig. 1 above, the thermal tripping mechanism (24) or the electromagnetic tripping mechanism (25) will operate, causing the fredle (19) and latch (29) to close. 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, the connection point between the fredle (19) and the lower link 17) is connected to the operating spring (23).
, the toggle link mechanism (16) is bent by the spring force of the operating spring (23), and the cross spar (
12), automatic shutoff is performed 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).
), the fixed contact (6), the movable contact (9) 8, and the moving body 8). In this state, if a large current such as a short circuit current flows through this circuit,
As described above, the movable contact (9) is separated from the fixed contact (6). At this time, an arc (32) is generated between the fixed and 6f moving contacts (9), and the fixed and moving contacts (6f)
) and (9), an arc voltage is generated between them. 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 (32) is directed toward the arc extinguishing plate (14) by magnetic force. It rises further because it is attracted by and elongates. 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). As a result, not only the contacts (6) and (9) are significantly worn out, but also the arc (32) has difficulty in contacting the arc extinguishing plate (14), so cooling is difficult. was not obtained.

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).
No spot is formed on the surface of the arc-extinguishing plate (14) when the current is large.

The arc voltage also does not increase much. Therefore, as shown in Figure ys6, the arc voltage V increases with the current I, but decreases with the decrease of the electric current I.

This is because the arc (32) is not long enough.

This is because the arc (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 emitted particularly strongly into the space created by the straight line E forming an angle of about 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 FIG.
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 for the angle 0 formed with the plane.

That is, as shown in FIG. 10, the arc extinguishing plate (14) is
The arc transition part (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 m, 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 ■0 at the current zero point, and the level of this sustaining voltage ■O depends on when the foot of the arc (32)
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 by θ being approximately 45°. That is, if θ°≦θ≦45°, the legs of the arc (32) can reliably form a spot at the arc transition portion (141). However, if it exceeds 0 or 45°, the arc (3
2) Metastasis becomes rapidly difficult. This means that the current flowing through the arc extinguishing plate (14) indicated by I in Fig. 9 causes the arc (32) to
It is thought that the electromagnetic repulsive force 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 0°≦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 necessary to maintain O. 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.

Incidentally, the thickness of the conductive portion of the arc is generally the smallest at the legs of the arc, and increases as the distance from the legs of the arc increases. It is known that the thinner the conductive part is, the higher the arc voltage becomes. Therefore, if the conductive part of the arc is made thinner by some method, the arc voltage will increase and the current limiting effect will be improved.

Therefore, in the above embodiment, the relationship between the area S1 of the tip surface (81) of the movable conductor (8) and the area S2 of the arc transition and pole part (141) is as shown in FIG. Choose this. In this way, once the arc leg forms a spot at the arc transition part (141), the arc leg at the arc transition part (141) is narrowed and becomes thinner, so the arc voltage increases and is limited. The flow effect can be further improved.

In addition, considering the original purpose of the arc transition part (141) in the above embodiment, while the movable contact (7) moves to the final opening position, at least the fi mechanical contact (7)
It goes without saying that it must be in a position where it can face the distal end surface at least once.

FIG. 16 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. 17.Furthermore, the shape of the arc transition portion (141) is not limited to the embodiment described in -1-, for example, as shown in FIG. 18 or 19. Various types as shown in the figure are possible. In addition,
The fixed contact (4) may be a so-called repulsion contact that separates from the movable contact (7) in response to electromagnetic repulsion caused by the applied current.

Also, in the above embodiment, the switch was explained as an example, but
In addition to the switch of the present invention, the present invention can also be applied to electromagnetic switches, current limiters, etc. that generate arcs within the housing.

[Effects of the Invention] As explained above, 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 and the arc Since the plane of the transition part is opposed to the plane at an angle of 45 degrees or less, the arc can be reliably transferred to the arc extinguishing plate, and the arc voltage can be increased to improve the interrupting performance.
Wear of contacts can also be reduced. Furthermore, since the area of the arc transition portion is made smaller than the area of the tip surface of the movable contact, the current limiting effect can be improved by narrowing the arc, and the breaking performance can be further improved.

[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 is a perspective view showing the relationship between the area of the tip surface of the movable conductor and the area of the arc transition part, and Fig. 16 (a) FIG. 16(b) is a front view showing another embodiment of the invention, FIG. 17 is a front view showing another embodiment of the invention, and FIGS. 18 and 19 both show the invention. FIG. 3 is a perspective view showing another embodiment of the invention. (3)・Fixed housing, (4)・Φ・Fixed contact, (6)・
...Fixed contact, (7)...Movable contact, (9)...
Movable contact, (14)... Arc extinguishing plate, (32)... Arc, (81)... Tip surface, (141)... Arc transition portion. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa

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 the two contacts. 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 extinguishing plate and are opposed to each other at an angle of 45° or less, and the area of the arc transition portion is smaller than the area of the tip surface of the movable contact. (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.