JPS641891B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit breaker which has an improved fixed contact and improved shearing performance.

Conventionally, the conductor is composed of a conductor and a contact fixed to the conductor, and has at least one pair of a fixed contact and a movable contact that are paired with each other, and when the two contacts are closed, the conductor is linearly moved. In circuits and breakers that are arranged so that the current flowing through the conductor is almost linear and points in the same direction, the magnetic force caused by the current is not strong, which can cause the arc to stick and deteriorate the cutting performance. . This will be explained in detail based on FIGS. 1 to 4.

Figures 1a and 1b show conventional circuit breakers. In this figure, reference numeral 10 denotes an enclosure that forms the outer frame of the circuit or disconnector, and is made of an insulating material.
Reference numeral 20 denotes a fixed contact, which is formed by fixing a fixed contact 202 to the tip of a fixed conductor 201 fixed to the enclosure 10. Reference numeral 30 denotes a movable contact pairing with the fixed contact 20, which includes a movable conductor 301 driven by the operating mechanism section 40, and a movable conductor 301 fixed to the tip of the movable conductor 301, which is connected to the fixed contact 20 of the fixed contact 20.
2, and a movable contact 302 that moves toward and away from 2.
50 is an arc extinguishing plate, and the movable contact 302 is the fixed contact 20
This is to cool the arc 60 that occurs when the arc 60 separates from the arc 2.

Now, when the movable contact 302 and the fixed contact 202 are closed, current flows along the path of the fixed conductor 201 → fixed contact 202 → movable contact 302 → movable conductor 301. As described above, when the fixed contact 20 and the movable contact 30 are closed, the fixed conductor 201 and the movable conductor 301 are arranged linearly with each other, and the current flows through the conductors 201 and 301. are almost straight and pointing in the same direction. In this state, when a large current such as a short circuit current flows through the circuit, the operating mechanism section 40 operates to separate the movable contact 302 from the fixed contact 202. Along with this operation, the fixed contact 202 and the movable contact 302
An arc 60 occurs in between. This arc 60 moves in the direction of the arc extinguishing plate 50 due to the magnetic force of the current flowing through the movable conductor 301 and the attractive force of the arc extinguishing plate 50.
It contacts the arc extinguishing plate 50. The arc 60 is the arc extinguishing plate 50
When it comes into contact with it, it is further subjected to a magnetic attraction force, and the arc is extinguished by being elongated and cooled.

Figure 2 shows the fixed contact 202 and the movable contact 302.
FIG. 3 is an explanatory diagram of magnetic force exerted by a current flowing between the two. In this figure, a current I ₁ flows through the fixed conductor 201 from right to left in the figure, and a current I ₂ similarly flows through the movable conductor 301 . Now, fixed contact 2
An electromagnetic repulsive force Fb from the movable conductor 301 is acting on the arc 60 generated between the movable contact 302 and the movable contact 302. The direction of this force is away from the movable conductor 301 as indicated by the arrow in the figure, and its strength is large near the movable contact 302. Further, an electromagnetic repulsion force Fa acts from the fixed conductor 201, and its direction and strength exhibit characteristics completely opposite to those described above. Therefore, the arc 60 receives a driving force toward the tip of the movable conductor 301 on the movable contact 302 side, and toward the movable conductor 301 on the fixed contact 202 side. The arc 60 subjected to the force in the opposite direction not only does not expand its positive column but also has difficulty moving in the direction of the arc extinguishing plate 50 shown in FIG. Therefore, the shear cutting performance could not be said to be good. From this, in order to extend or drive the arc 60 in the direction of the arc extinguishing plate 50 and improve the shearing performance, it is necessary to extend or drive the arc 60 from the fixed conductor 201 to
It can be seen that it is necessary to reduce the force of Fa exerted on .

Therefore, in order to reduce the above-mentioned force Fa, the inventor has provided the fixed conductor 201 with a wire that is located on both sides of the fixed contact 202 and penetrates the front and back of the fixed conductor 201, as shown in FIGS. 3a and 3b. An application in which grooves 70 are provided in the direction along the current flow was filed on the same date. That is, by providing the groove 70 in the fixed conductor 201, the outer part 80c of the groove 70 is always
Since the current path that reaches the fixed contact 202 through the conductor center portion 80a is longer than the current path that reaches the fixed contact 202 through the conductor central portion 80a, the resistance increases accordingly, and as a result, the current flows through the outer portion 80c. Although almost no current flows, it becomes a large current during a short circuit, so this large current is the current flowing through the central part 80a of the conductor.
At the terminal end of the groove 70, the current Ic flows from the outside of the groove 70 in the opposite direction through the conductor end 80b and reaches the fixed contact 202. Moreover, since the conductor central portion 80a generates heat due to the large current Is and the resistance increases, the conductor end portion 80b passes through the outer portion 80c.
The current Ic flowing through increases. As a result, the component of the magnetic force acting on the arc 60 in the right direction in the drawing increases due to the current Ic flowing through the conductor end 80b, and the arc 60 generated at the fixed contact 202 is more likely to be driven in the right direction in the drawing.

Although such a fixed contactor 20 functions effectively while the arc 60 is present on the conductor central portion 80a, in reality, the leg of the arc 60 may move to the outer portion 80c of the groove 70. , the presence of the current Ic at the conductor end 80b reduces the driving force acting, and the driving force is extremely lost, so that the arc 60 does not travel in a predetermined direction, and the arc 60 does not run smoothly. Performance sometimes deteriorated. Figure 4 shows this situation. That is, FIG. 4a also shows the point where the arc 60 has its foot in the shaded area A of the outer part 80c of the fixed conductor 201 and the driving force is lost, and FIG. 4b shows the cross section of FIG. The figure shows the arc 60 sticking to the above-mentioned outer portion 80c and contacting the arc extinguishing plate 50.

This invention was made to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide a circuit or breaker that can guarantee the running of an arc and ensure cutting performance.

Embodiments of the present invention will be described below based on the drawings.

FIGS. 5a and 5b show a fixed contact 20 of a circuit breaker according to an embodiment of the present invention. In this figure, the fixed contact 20 consists of a fixed conductor 201 and a fixed contact 202 fixed to the fixed conductor 201, as in FIG. A groove 70 is provided that penetrates the front and back sides of 201 and extends in the direction of the current flow. The front edge (left edge) of this groove 70 matches, for example, the front edge (left edge) of the fixed contact 202. On the other hand, the rear edge (right edge) of the groove 70 is located further back (on the right side) than the rear edge (right edge) of the fixed contact 202 .

In this invention, the conductor surface of the outer portion 80c of the groove 70 is covered with a covering member 90 made of an insulator or a metal material having higher resistance than the fixed conductor 201. In this way, the legs of the arc 60 are placed in the groove 7.
0 is not present in the outer part 80c of the conductor, and is not present in the conductor central part 80c.
It becomes possible to exist only in a. Therefore, since the arc is guaranteed to travel in the direction along the conductor central portion 80a, it receives the driving force of the current Ic (see Fig. 3) flowing through the conductor end portion 80b appropriately, and the shearing performance is ensured. be done.

FIG. 6 shows another embodiment of the invention. In FIG. 6, the surface of the conductor other than the fixed contact 202 and the conductor central portion 80a is covered with a covering 90 made of the above-mentioned insulator or high-resistance metal.

In this way, when the periphery of the fixed contact 202 is also covered with the above-mentioned covering 90, the arc generated at the fixed contact 202 is quickly driven away from the fixed contact 202. This is due to the following reason.

The legs of the arc generated at the fixed contact 202 expand as the current increases, and a portion of it expands into the conductor central portion 80a.
to invade. That is, since the fixed contact 202 is covered with the covering 90 made of an insulating material or a high-resistance metal material, the legs of the arc are forced to contact the fixed contact 2.
02 It means that he was ejected outside. Furthermore, since the heating of the conductor surface by the conductive gas emitted by the arc is limited to the conductor central portion 80a, the movement of the legs of the arc is limited to the conductor central portion 80a and is accelerated.

As mentioned above, by covering the area around the fixed contact 202 with the coating 90 made of an insulating material or high-resistance metal while leaving the traveling direction of the arc intact, the arc can be driven quickly. Become.

FIG. 7 also shows another embodiment of the invention. In FIG. 6, the conductor central portion 80a is not coated with insulation, but in the example of FIG. 6, the conductor central portion 80a is exposed with a width that allows the arc to travel
In other words, leaving the necessary minimum width arc running path 100,
It is covered with a covering 90 made of an insulating material or a high-resistance metal material. In this way, the effect of driving the arc is the same as that shown in FIG. 5, but by appropriately adjusting the width of the arc traveling path 100, the existing range, traveling route, and direction of the arc can be controlled. Therefore, when used in conjunction with the arc extinguishing plate 50, which is a general arc extinguishing device, the arc can be guided to a predetermined position on the arc extinguishing plate 50, since the location of the arc is limited in the arc travel path 100. The cutting performance can be significantly improved.

As shown in FIGS. 6 and 7, the length of the groove 70 is longer than the fixed contact 202, and both ends 110a, 110b of the groove 70 extend beyond the side surfaces 120a, 120b of the fixed contact 202. It is clear that it is effective.

Further, the covering body 90 is made of an insulating material or a high-resistance metal material, and the insulator is an organic or inorganic insulator, and the high-resistance metal material is nichrome/kanthal, carbon-iron, etc. It is.

As can be seen from the above description, according to the present invention, it is possible to provide a circuit breaker that can guarantee arc travel and ensure cutting performance.

[Brief explanation of drawings]

Fig. 1a is a partially cutaway plan view of a conventional circuit breaker, Fig. 1b is a sectional view taken along line 1b-1b of Fig. 1a,
Figure 2 is an explanatory diagram of the force acting on the arc of a circuit breaker not included in this invention, Figure 3a is a plan view of a fixed contact of a circuit breaker not included in this invention, Figure b is a sectional view taken along the line 3b-3b in Figure 3a, Figure 4a is an explanatory diagram of the arc in a conventional fixed contact, Figure 4b is a sectional view taken along the line 4b-4b in Figure 4a, and Figure 4b is a sectional view taken along the line 4b-4b in Figure 4a. Figure a is a plan view of a fixed contact of a circuit breaker according to an embodiment of the present invention, and Figure 5b is 5b-5 of Figure 5a.
The b-line enlarged sectional view, FIGS. 6 and 7 are plan views showing other embodiments of the fixed contact according to the present invention. 20... Fixed contact, 201... Fixed conductor, 2
02... Fixed contact, 30... Movable contact, 301
...Movable conductor, 302...Movable contact, 70...
Groove, 90...covering body, 110a, 110b...both ends, 120a, 120b...both end side surfaces. In addition,
In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1 Consisting of a conductor and a contact fixed to the conductor, having at least one pair of a fixed contact and a movable contact that are paired with each other, and when the two contacts are closed,
In circuits and breakers in which the conductors are arranged linearly and the current flowing through the conductors is almost linear and points in the same direction, the fixed conductors on both sides of the fixed contact of the fixed contact are connected to the front and back sides of the fixed conductor. A groove is provided in the direction along the current flow, and the front edge of this groove matches or is located forward of the front edge of the fixed contact, and the rear edge of the groove is located in front of the rear edge of the fixed contact. A circuit breaker or breaker located at the rear of the groove, characterized in that the surface of the fixed conductor outside the groove is covered with an insulating material or a metal material having a higher resistance than the conductor.