JPS6072124A - 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 improves the 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 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 an fjl moving contact, which has a movable conductor (8) and a fixed contact (
6) has a movable contact (9) opposite to. (10)
1 is a movable contact device, and (11) is an I+) disconnection contact arm, which is fixed to a crossbar (12) and is opened and closed when each pole is connected. (13) is the arc extinguishing room, and the arc extinguishing plate (14)
is held by the side plate (15). (16) is a toggle link mechanism, with upper link (17) and lower link (18)
It is composed of One end of the upper link (17) is connected to the fredle (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 contact device (i
o) is connected to the movable arm (11). (22) is a raising/lowering operation handle, and (23) is an operating spring, which 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, and when activated, bimetal (26) and movable iron core (2
7) rotates 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 7g is shown in FIG.

Next, when the operating handle (22) is tilted to the open position, the toggle link mechanism (16) is bent and the movable contact (9) is separated from the fixed contact (6), and the movable arm (11) is set to 1 relative to the Fredel axis (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 engagement is released, the frettle (19) rotates clockwise around the frettle shaft (30), and is locked to the stopper shaft (31). At this time, the connection point between the fredle (■9) and the seventh link (17) crosses the line of action of the operating spring (23), so the toggle link mechanism (16) is bent by the spring force of the operating spring (23). Crossbar (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 is 1)Fllll of the movable contact (9) from the fixed contact (6)
It rises as the lll distance increases, and at the same time, the arc (32) is drawn toward the arc extinguishing plate (14) by the magnetic force and extends, so it further rises. In this way, the arc current reaches the electric*zero point, the arc is extinguished, and the interruption is completed.

Next, the conventional shutoff operation will be explained in more detail based on FIG. 4.

Figures 4 (a), (b), and (c) are the early and middle stages of contact opening during cutoff, respectively. It shows the state of the arc in the later stages.

In Fig. 4(a), at the start of the opening operation, the arc (
32) occurs between contacts (6) and (9), and its foot is on contacts (6) and (9). Over time, the legs of the arc (32) expand with increasing current, and their size reaches the point of contact (6).

(9) and gradually expands to the surfaces of conductors (5) and (8). At this time, as is generally known as the arc stagnation phenomenon, even if a strong magnetic field is applied to the fired arc, its legs do not move for 2 to 3 m5ec. Therefore, as shown in Fig. ff14 (b), the center of the leg of the arc (32) is located at the contact points (6) and (9), and it expands around that point.

Further, when the opening progresses and about 3 msec has passed, the legs of the arc (32) are connected to the movable conductor (8).
Due to the electromagnetic force caused by the current flowing through the conductor (8), the arc (32) moves to the arc transition surface (81) formed at the tip of the conductor (8), as shown in Figure 4 (C), and the path of the arc (32) changes accordingly. Eventually, the current will reach zero point.

However, the arc (32) generated in this type of conventional contactor is caused by the arc (32) on the surfaces of the conductors (5) and (8).
Since the legs of 2) expand freely, the legs of the arc (32) become larger, and the positive pillar of the arc (32) also becomes thicker. For this reason, the electrical conductivity of the arc (32) increases and the arc voltage does not rise, so there is a drawback that a current limiting effect cannot be expected when a large current is interrupted.

FIG. 5 shows another embodiment. In the one in Figure 5, the surfaces of the four bodies (8) are covered with an insulator (40),
Only the contact (9) is exposed. If you do this,
By limiting the size of the legs of the arc (32) to the size of the contact (9), the area of the legs of the arc (32) can be reduced, thereby increasing the arc voltage.

However, although this type of contactor has a remarkable current limiting effect, since the foot of the arc (32) is always at the contact point,
Cooling by the arc extinguishing plate (14) at the current zero point was not sufficient, and the interrupting performance was not good.

FIG. 6 shows yet another conventional example, in which the arc running path (82
) and the arc dislocation plane (81) are exposed. According to this structure, the arc can freely move along the traveling path (82) and the arc dislocation plane (81), so the interruption at the current zero point is good. path (82), arc dislocation surface (81)
, the arc (32) had a large foot and there was no sufficient voltage rise, so no current limiting effect could be expected.

[Summary of the Invention] This invention was made to eliminate the above-mentioned conventional drawbacks, and aims to provide a switch with improved current limiting effect and improved breaking performance. shall be.

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

FIG. 7 shows an example of a movable contactor in this invention, (
(a) is a perspective view, (b) and (e) are a plan view and a front view, respectively. In the figure, (8) is a movable conductor, (9)
is the movable contact, (81) is the arc transition surface, (82) is the arc traveling path on the same plane as the contact fixed surface, and the insulator (4
0) covers the surface of the movable conductor (8) except for one side facing the arc travel path (82) of the movable contact (9). The arc transition surface (81) forms an angle of 0 with the contact fixing surface of the movable conductor (8), and θ has an angle of 50° or more. In addition, the area of the arc transition surface (81) is the contact point (
9) and the area of the arc travel path (82).

, Here, the reason why O (hereinafter, this angle is referred to as the inclination angle) is set to 50° or more is as follows. That is, as a result of various studies conducted by the inventors regarding the relationship between the inclination angle and the arc voltage, it was experimentally confirmed that there is a relationship between the two as shown in FIG. 8.

As can be seen from Figure 8, the arc voltage has an inclination angle of O~
There is only a slight fluctuation up to 50', but from the time O exceeds 50°, especially from the time O exceeds 60°, the arc voltage increases as the inclination angle increases. This is because when the inclination angle is 500 or more -LL, it becomes difficult for the legs of the arc to expand. Then, when 0 is 90°, the arc voltage becomes 1° and the maximum is 4fi Vmax. Therefore, in order to obtain a high arc voltage, it is necessary to set θ to 50' or more.

Next, the actual instantaneous operation will be explained.

FIGS. 9(a), (b), and (e) show the early stage of opening, the middle stage of opening, and the late stage of opening, respectively. At the beginning of contact opening, an arc (32) is generated between contacts (6) and (9) with the opening operation as shown in (a), and its legs are connected to contacts (6) and (9).
(9) Fixed on top.

Even if the opening progresses and the opening distance increases, the arc (3
2) is due to the sticking phenomenon, as shown in (b), the contact point (6
), (9) remains above. At this time, arc (3
A part of the leg 2) expands to the arc running path (82), but due to the above-mentioned reason, the contact surface and the arc running path (82)
2) shows the increase in arc voltage according to the total area.

Generally, the arc (32) stagnation is 2-3 m sec
However, when a low-voltage switch is activated immediately, the current limiting effect against the large current is determined by the degree of the arc voltage 2 to 4 m5ec after the switch is opened. If the arc voltage is increased even for this short period of time, the current limiting effect will be improved.

Therefore, as mentioned in Section 2, if the arc transition surface (81) of the conductor (8) is rounded up to 50' or more, the legs of the arc (32) during the arc stagnation period are
1), the arc voltage increases because the size of the arc (32) leg is limited. In this manner, at the time of current limitation in the initial stage of contact opening, the current limitation is determined by the sum of the areas of the contact surface and the arc travel path.

Next, the sticking of the arc (32) is relaxed over time, and when an external force is applied, the arc (32) becomes movable. At this time, since the area of the arc transition surface (81) is larger than the sum of the area of the surface of the contact point (9) and the area of the arc travel path (82), the arc (32) has a large area of the arc transition surface (81). ), and the legs of the arc (32) become stable at this transition surface (81). After this stabilization, the legs of the arc (32) do not enter the fixed surface of the contact (9). In other words, the legs of the arc (32) will not expand.

Therefore, the period during which the legs of the arc (32) exist on the surface of the contact (9) is 3 m s e which affects the current limiting effect.
c, and thereafter there are no legs of the arc (32) on the surface of the contact (9). Therefore, contact wear due to arcing can be significantly reduced.

After the transition of the arc (32), as shown in FIG. 9(C),
The length of the path of the arc (32) is significantly increased compared to the conventional one. This is because the determining factor for the path of the arc (32) is the rupéhagen i where the arc (32) is generated, and this paper agent blows almost perpendicularly to the surface of the conductor where the legs of the arc (32) are located. . Therefore, when the leg of the arc (32) moves to the arc transition surface (81), the leg of the arc (32) becomes smaller and the length of the arc (32) increases, which together causes a large arc voltage. occurs, resulting in significant current limiting of the arc (32). In addition to current limiting, since the paper agent blows directly and intensely onto the arc extinguishing plate (14), the arc (32) positive column is strongly cooled, and therefore the breaking ability at the zero current point is reduced. Significantly improved.

In this way, the combination of the contact and the arc-extinguishing plate (14) shown in Fig. 7 provides current limiting, and also shortens the breaker time and improves the breaker performance by increasing the arc voltage in the second half of the breaker. I can do it. In addition, contacts (6), (9
), the residence time of the arc (32) is short, resulting in less contact wear.

FIGS. 10(a), (b), and (C) show other embodiments of the contactor. In these embodiments, the contact (9)
The width of the arc traveling path (82) is formed to be larger than the width a of the arc traveling path (82). In this way, the foot of the arc (32) generated on the contact point (9) can more quickly move to the arc travel path (82).
Since the contact point (9) can be moved from the arc transition surface (81) to the arc transition surface (81), the wear of the contact point (9) is further reduced.

FIG. 11 shows yet another embodiment, in which, contrary to the description,
The width of the arc running path (82) is made smaller than the width a of the contact point (9). If this is done, the foot of the arc (32) will be sufficiently spread over the running path (82) during the initial stage. Since it cannot penetrate and expand, its size is limited;
This increases the arc voltage. Furthermore, even if some external force is applied after commutation, the arc (32) will not flow backwards onto the surface of the contact (9), ensuring a sufficient current limiting effect.

Furthermore, as shown in Fig. 12, if the surface of the arc running path (82) is made higher than the fixed surface of the contact (9), the foot of the contact (9) can directly touch the fixed surface of the contact (9). Since it does not penetrate, it is possible to prevent the contact (9) from falling off due to melting of the contact fixing surface.

Figure 13 shows an example where the contact point (9) is in direct contact with the contact transition surface (81), also serving as an arc travel path, and Figure 14 shows an example where the contact point (9) is in direct contact with the contact transition surface (81), which also serves as an arc travel path.
40) covers a part of the arc transition surface (81).

Figure 15 shows one with parallel conductor parts, and the angle formed by the arc transition surfaces (51) and (81) with the recontactor is 50°.
That's all. In such a contact arrangement,
Because the electromagnetic repulsion is strong and the arc stagnation is slightly shortened,
Contact wear is further reduced.

Further, the arc transition surface (81) at the tip of the conductor does not necessarily have to be a flat surface, but may be a curved surface as shown in FIG. 16 as long as the angle thereof is 500 or more.

Furthermore, as shown in FIG. 17, by covering the conductor (8) with the insulator (40) even on its sides, when the foot of the arc (32) moves to the arc transition surface (81),
It is possible to prevent the arc (32) from expanding to the side of the leg conductor (8).

That is, the size of the legs of the arc (32) is limited. This makes it possible to maintain a high arc voltage and maintain good current limiting property f above ζ. Furthermore, when cutting off the load and overload currents, the legs of the arc (32) collapse on the sides and become stuck, making it impossible to cut off the current.

In the above embodiments, the movable contactor was mainly explained, but the same can be said for the fixed contactor.

Furthermore, the present invention is not limited to circuit breakers, but can also be applied to electromagnetic switches, current limiters, etc. that generate arcs (32) within the housing.

[Effects of the Invention] As explained below, according to the present invention, since the angle formed between the arc transition surface and the contact fixing surface of the conductor is set to 500 or more, the size of the arc foot is limited. Since the area of the arc transition surface is larger than the sum of the area of the contact surface and the area of the arc traveling path, commutation of the arc occurs quickly,
A switch with less contact wear can be provided.

[Brief explanation of drawings]

Figures 1 to 3 are cross-sectional views showing different operating states of a conventional circuit breaker, and Figure 4 is a diagram for explaining the breaking operation of a conventional circuit breaker.
5 is a diagram showing the early stage of contact opening, (b) is a diagram showing the middle stage of contact opening, and (c) is a diagram showing the late stage of contact opening. FIG. 5 shows a contact in another embodiment of a conventional circuit breaker, and (a) is a plan view. , (b) is a front view, FIG. 6 shows a contact in another embodiment, and (a)
7 is a plan view, FIG. 7 is a front view, FIG. 7 is a perspective view, FIG. 7 is a plan view, FIG. The figure shows the relationship between the inclination angle and the arc voltage, and FIG. 9 is a diagram for explaining the breaking operation in the embodiment of the present invention. (a) shows the initial stage of contact opening,
(b) is the middle stage of opening, (C) is the late stage of opening, 1st O
17 to 17 all show other embodiments of the present invention, and FIGS. io (&), (b), and (C) are plan views of different embodiments, and FIGS. ) and (C) are plan views of different embodiments, FIG. 12 is a front view, and FIG.
The figure is a plan view, Fig. 14 (a) is a plan view, (b) is a front view, Fig. 15 is a front view, Fig. 16 is a front view, and Fig. 17 (a).
) shows a front view, and (b) shows a side view. (4)... Fixed contact, (5)... Fixed conductor, (6
)...Fixed contact, (7)...Movable contact, (8)...
Movable conductor, (9)...Movable contact, (40)...
Insulator, (81)...Arc transition surface, (82)@...
arc running path. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa

Claims (4)

[Claims] (1) It has at least one pair of contacts consisting of a conductor and a contact fixed to the conductor, and the contact surface and the arc In a switch that is coated with an insulator, leaving a running path, and forming an arc transition surface at the tip of the conductor, the area of the arc transition surface is equal to the area of the contact surface and the area of the arc travel path. and the angle between the arc transition surface and the contact fixation surface of the conductor is 50°.
A switch characterized by the above. (2) The switch according to claim 1, wherein the width of the arc travel path is larger than the width of the contact. (3) The switch according to claim 1, wherein the width of the arc travel path is smaller than the width of the contact. (4) The switch according to claim 1, wherein the surface of the arc travel path is higher than the fixed surface of the contact.