JPH0351878Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a circuit breaker with improved breaking performance.

Generally, in this type of circuit breaker, the direction of the current flowing through the fixed contact and the movable contact is the same,
In those configured to be almost parallel,
Since the magnetic force generated by the current is not strong, arc drive or arc extension is insufficient, making it difficult to increase the arc voltage, resulting in extremely poor arc extinguishing performance and shearing performance.

FIG. 3 is an explanatory diagram of the magnetic force in the fixed conductor and the movable conductor, which are arranged substantially parallel to each other with the same current direction.

In the figure, a current I ₁ flows through the fixed conductor 3 in the direction of the arrow, and a current I ₄ similarly flows through the movable conductor 6. Now, an electromagnetic repulsive force Fb is acting from the movable conductor 6 against the arc 9 generated between the movable contact 7 and the fixed contact 4 when the circuit breaker is closed, and this repulsive force Fb is The direction is the direction away from the movable conductor 6 as shown by the arrow in the figure, and its strength is large near the movable contact 7 and becomes smaller as it approaches the fixed conductor 3. On the other hand, an electromagnetic repulsive force Fa acts from the fixed conductor 3, and its direction and strength are completely opposite to those of the movable conductor 6 described above.

Therefore, the arc 9 receives a driving force toward the tip of the movable conductor 6 on the movable contact 7 side, and
On the fixed contact 4 side, the driving force is applied in the direction of the tip of the fixed conductor 3, so the arc 9 that receives the driving force in the opposite direction does not expand its positive column, making it difficult for the arc voltage to rise. However, since this arc 9 is difficult to move in the direction of the arc extinguishing plate 10, cooling by the arc extinguishing plate 10 is insufficient, resulting in a decrease in arc extinguishing performance and shearing performance.

As a means to improve the above-mentioned problems, conventionally, as shown in FIG. Disclosed is an arc forming surface 11b of an arc running plate 11 that moves an arc 9 generated therebetween toward an arc extinguishing plate 10, which is arranged lower than the surface 4a of the fixed contact 4 by a step s. (Refer to Japanese Utility Model Application No. 50-87451.) This is because when the arc 9 on the fixed contact 4 is commutated onto the arc traveling plate 11, the positive column of the arc 9 is extended by the step s, and the arc voltage is increased. In addition to having the effect of improving the shear cutting performance by raising the temperature, it is also possible to have a function as described below.

FIG. 5 shows the fixed contact 4 in FIG. 4 above,
This is an explanatory diagram for explaining in detail the configuration and operation of the arc traveling plate 11, and the bent part 3e side end 3d of the fixed conductor 3 is made of a magnetic good conductor such as iron that extends the arc extinguishing plate 10 in the direction. Together with the arc running plate 11,
A fixed contact 4 corresponding to the movable contact 7 is fixed by welding or caulking, and is configured such that the direction of the current I _{2 flowing through the fixed contact 4 is perpendicular to the current I 1 flowing} through the fixed conductor 3. It's there.

Further, the arc running plate 11 is used to commutate the arc 9 generated on the fixed contact 4 from above the fixed contact 4 toward the arc extinguishing plate 10, so that the current I flowing through the fixed conductor 3 ₁ and is arranged to generate a current I ₃ parallel to and in a different direction. In other words, it is configured to form a current path parallel to and in a different direction to the current flowing through the movable conductor 6.

Further, the arc forming surface 11b of the arc traveling plate 11 is located at a position lower than the surface of the fixed contact 4 by a step s.

Next, the operation and effects of the above configuration will be explained.

Now, in FIG. 5, when an arc 9 occurs between the fixed contact 4 and the movable contact 7, this arc 9
The electromagnetic repulsive force Fa acting on can be approximately expressed by the following equation.

Fa=uI ² /4π(y+h) However, in the above equation, I is the current, u is the magnetic permeability, h is the fixed contact height, and y is the height from the fixed contact to an arbitrary point on the arc.

The electromagnetic repulsive force Fa has a characteristic completely opposite to the electromagnetic repulsive force Fb described in FIG. 3, and is small near the movable contact 7 and becomes larger as it approaches the fixed contact 4. Moreover, since the force acts in the direction away from the arc-extinguishing plate 10, if the height h of the fixed contact 4 is increased by the bending part 3e of the fixed operating position 3, as shown in FIG. 5, Fa becomes smaller. On the contrary, the electromagnetic repulsion force Fb of the opposite characteristic due to the movable conductor 6 described in FIG. 3 becomes relatively large, and the arc 9 greatly extends toward the arc extinguishing plate 10 side.

In the circuit breaker configured as described above, the arc 9 on the fixed contact 4 is connected to the arc traveling plate 11.
When the current is commutated upward, the movable conductor 6 and the arc traveling plate 11
Since the current flowing through the arc 9 and the arc 9 are configured so that they run in opposite directions, the arc 9 is driven in the direction of the arc extinguishing plate 10 by the electromagnetic repulsion, and the cooling effect of the arc extinguishing plate 10 is improved. Furthermore, since the arc forming surface 11b of the arc running plate 11 is arranged at a position lower than the surface 4a of the fixed contact 4 by the step s, the arc 9 on the fixed contact 4 is commutated to the arc running plate 11. Then, due to the step s, the positive column portion of the arc 9 is elongated, the arc voltage increases rapidly, and the shearing performance is improved.

However, in this type of circuit breaker having the arc running plate 11, the shear breaking capacity varies depending on the magnitude of the rated current, the shear cutting method, the shear cutting structure, etc. For example, in the case of large current or high voltage, the arc 9 of a circuit or disconnection is caused by the arc running from the fixed contact 4 to the arc traveling plate 1.
1, so in order to make it easier for the arc to commutate to the arc running plate, the arc length immediately after commutation is shortened and the arc voltage is lowered.
The arc forming surface 11b of 1 is connected to the surface 4a of the fixed contact 4.
In other words, it is necessary to make the step s smaller.

In addition, the arc 9 of a circuit or breaker in the case of a small current or low voltage is easily commutated from the fixed contact 4 to the arc traveling plate 11, so the arc voltage is low and the cutting performance is poor, so the arc length is In order to increase the arc voltage by increasing the arc voltage, it is necessary to move the arc forming surface 11b of the arc traveling plate 11 away from the surface 4a of the fixed contact 4, that is, it is necessary to increase the step s.

However, in the above-mentioned circuit breakers (Japanese Utility Model Application Publication No. 50-87451), the arc forming surface 11b of the arc traveling plate 11 and the surface 4 of the fixed contact 4
Since the step s from the fixed conductor 3 is determined by the thickness of the fixed contact 4, in order to adjust the step s, the thickness of the fixed contact 4 must be adjusted before it is fixed to the end 3d of the fixed conductor 3. Therefore, it is necessary to prepare a large number of fixing settings 4 with different thicknesses, which has the drawback of being extremely uneconomical and leading to increased costs.

Further, as described above, as another example in which the arc forming surface 11b of the arc traveling plate 11 is arranged lower than the surface of the fixed contact 4, as shown in FIG. After inserting the fixed leg plate 11c of the arc traveling plate 11 into the mounting hole 1a, crush it and attach the arc traveling plate 1 near the fixed contact 4.
1 is shown in which it is fixed.
(Refer to Japanese Utility Model Application No. 57-76346.) However, in this case as well, the step s between the arc forming surface 11b of the arc running plate 11 and the surface 4a of the fixed contact 4 depends on the thickness of the arc running plate 11 or the fixed contact 4. Therefore, in order to adjust the step s, it is necessary to select the thickness of the arc traveling plate 11 and the fixed contact 4. This also has the drawback of being uneconomical and leading to increased costs.

This idea was made to improve this problem, and without using arc running plates or fixed contacts of different thicknesses, it is possible to eliminate the difference in level between the arc running plate and the fixed contact, that is, the height of the arc running plate relative to the fixed contact. The purpose of the present invention is to provide a circuit breaker or breaker in which the height of an arc forming surface can be adjusted.

An embodiment of this invention will be described below based on the drawings.

Fig. 1 is a side view of a fixed conductor with an arc running plate attached, and Fig. 2 is a plan view thereof. In the figure, parts that are the same as or corresponding to the conventional one shown in Fig. The detailed explanation thereof will be omitted.

Reference numeral 3b denotes a prismatic convex portion, which is configured to protrude a predetermined length from one end of the fixed conductor 3 corresponding to the movable conductor 6 having the movable contact 7, orthogonally thereto, toward the movable contact 7. . Reference numeral 3c denotes a mounting wall, which is formed on the side surface of the convex portion 3b on the arc-extinguishing plate 10 side. 4 is a fixed contact fixed to the tip surface of the convex portion 3b, 11 is an arc traveling plate made of a magnetic good conductor such as iron, and the arc 9 generated on the fixed contact 4 is
is moved toward the arc extinguishing plate 10.

Reference numeral 11a denotes a mounting seat formed at one end of the arc traveling plate 11, for example by bending this. After adjusting the mounting position (step s) of the arc forming surface 11b of the arc traveling plate 11 with respect to the surface 4a of the fixed contact 4, which varies depending on the shearing capacity, and positioning it at a predetermined position, the mounting seat 11a is attached to the convex portion 3b. The arc traveling plate 11 is attached to the mounting wall 3c of the convex portion 3b of the fixed conductor 3 by being fixed to the mounting wall 3c by welding or the like.

As described above, the present invention reduces the driving force of the current flowing through the main part of the fixed conductor to the arc in the direction opposite to the arc extinguishing plate direction by using the fixed conductor recess, and the arc travels only a distance that increases the arc resistance discontinuously. Since the plate is attached to the side surface of the fixed conductor recess apart from the fixed setting of the arc generation starting point, extremely excellent arc extinguishing performance can be exhibited.

[Brief explanation of the drawing]

Figure 1 is a side view showing the fixed conductor and movable conductor of the circuit breaker based on the invention, Figure 2 is a plan view of the fixed conductor, and Figure 3 is the fixed conductor and movable conductor of the conventional circuit breaker. Fig. 4 is a vertical cross-sectional view showing a conventional circuit breaker, Fig. 5 is an explanatory diagram of its operation, and Fig. 6 shows the main parts of another conventional circuit breaker. FIG. 3...Fixed conductor, 3b...Protrusion, 3c...Mounting wall, 4
... Fixed contact, 4a... Surface, 6... Movable conductor, 7... Movable contact, 9... Arc, 10... Arc extinguishing plate, 11... Arc traveling plate, 11a... Mounting seat, 11b... Arc forming surface. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] The movable conductor has a movable contact at one end, and the movable conductor has a central axis perpendicular to the center line of the main part of the fixed conductor. A circuit breaker comprising a fixed conductor convex portion to which a contact is fixed, an arc extinguishing plate for extinguishing an arc generated between the two contacts, and an arc traveling plate attached to the fixed conductor convex portion, The convex part of the fixed conductor reduces the driving force of the current flowing through the main part of the fixed conductor to the arc in the direction opposite to the direction of the arc extinguishing plate, and then moves the arc running plate to the starting point of arc generation by a distance that discontinuously increases the arc resistance. A circuit breaker, characterized in that it is attached to the side surface of the fixed conductor convex part away from the fixed contact.