WO2014155442A1

WO2014155442A1 - Circuit breaker

Info

Publication number: WO2014155442A1
Application number: PCT/JP2013/006395
Authority: WO
Inventors: 光武　義雄; 智士鈴木; 岡田　健治; 卓也香川
Original assignee: パナソニック株式会社
Priority date: 2013-03-27
Filing date: 2013-10-29
Publication date: 2014-10-02

Abstract

A circuit breaker is provided with a fixed contact point plate having a fixed contact point that comes into contact with and separates from a movable contact point, a magnetic body disposed near the fixed contact point plate and electrically insulated from the fixed contact point plate, and a device body for accommodating the fixed contact point plate. The fixed contact point plate induces an arc occurring between the movable contact point and the fixed contact point in a direction moving away from the movable contact point and the fixed contact point by the action of a magnetic field. The device body is configured by mutually joining a plurality of members using assembly screws. The magnetic body is then disposed so as to be permeable to a magnetic field generated on the periphery of the fixed contact point plate. The assembly screws are also used for the magnetic body.

Description

Circuit breaker

The present invention relates to a circuit breaker.

Conventionally, there has been known a circuit breaker including a link mechanism that opens and closes a contact in accordance with a handle operation and a trip mechanism that drives a link mechanism to forcibly open a contact when an abnormal current flowing in an electric circuit is detected. Such a circuit breaker is disclosed in, for example, Document 1 (Japanese Patent Application Publication No. 2009-212063). The circuit breaker described in this document 1 includes an arc extinguishing device for quickly extinguishing an arc generated when the contact is opened.

The arc extinguishing device is composed of an arc traveling plate and an arc extinguishing grid. The arc traveling plate is formed of a strip-shaped metal plate and guides the generated arc to the arc extinguishing grid. The arc extinguishing grid is configured by arranging a plurality of arc extinguishing plates in parallel along the thickness direction at a predetermined interval. The arc extinguishing grid breaks the induced arc. With this arc extinguishing device, when the movable contact leaves the fixed contact and an arc is generated, the arc is extended to extinguish the arc.

By the way, in the circuit breaker as in the above conventional example, the arc generated between the contacts is guided to the arc extinguishing grid by utilizing the Lorentz force acting on the arc. Here, in a circuit breaker that cuts off a large current, it is necessary to quickly extinguish the arc generated between the contacts, and therefore it is desirable to induce the arc to the arc extinguishing grid quickly. In addition, even in a circuit breaker that does not include an arc extinguishing grid, it is expected to guide the arc so that it is quickly moved away from the contact point.

To increase the Lorentz force acting on the arc, it is conceivable to guide the arc away from the contact point quickly. As a means for increasing the Lorentz force, for example, a fixed contact plate to which the fixed contact is fixed may be formed of a magnetic material such as iron. However, a circuit breaker that cuts off a large current has a problem in that it is difficult to adopt such a configuration because the resistance in the current path through which the current flows must be reduced.

The present invention has been made in view of the above points, and an object of the present invention is to provide a circuit breaker capable of guiding an arc generated between contacts so as to be quickly moved away from the contacts.

A circuit breaker according to a first aspect of the present invention includes a fixed contact plate having a fixed contact that contacts and separates from a movable contact, and is disposed in the vicinity of the fixed contact plate to be electrically insulated from the fixed contact plate. A magnetic body and a container for housing the fixed contact plate. The fixed contact plate induces an arc generated between the movable contact and the fixed contact in a direction away from the movable contact and the fixed contact by the action of an electromagnetic field. The said container is comprised by mutually connecting a some member with an assembly screw. And the said magnetic body is arrange | positioned so that the magnetic field produced around the said stationary contact plate may pass. Furthermore, the assembly screw also serves as the magnetic body.

In the circuit breaker according to the second aspect of the present invention, in addition to the first aspect, the magnetic body is arranged so that a magnetic field generated around the arc passes therethrough.

It is a figure which shows the model of the circuit breaker which concerns on embodiment of this invention. FIG. 2A is a side view showing the basic configuration of the circuit breaker according to the embodiment of the present invention, and FIG. 2B is a perspective view showing the basic configuration of the circuit breaker according to the embodiment of the present invention. 3A to 3D are views each showing an external appearance of the circuit breaker according to the embodiment of the present invention. It is a figure explaining the induction | guidance | derivation to the arc-extinguishing apparatus in the circuit breaker which concerns on embodiment of this invention. In a circuit breaker concerning an embodiment of the present invention, it is a figure explaining a magnetic field generated by arc current. 6A and 6B are diagrams for explaining the Lorentz force acting on the arc in the circuit breaker according to the embodiment of the present invention.

Hereinafter, in describing the circuit breaker 100 according to the embodiment of the present invention, the basic configuration of the circuit breaker 100 will be described with reference to the drawings. As shown in FIGS. 2A and 2B, the circuit breaker 100 includes a body 1, a first terminal portion 2, a second terminal portion 3, a contact portion 4, a link mechanism 5, a trip mechanism 6, And an arc extinguishing device 7. 2A and 2B show a state in which a cover 11 described later is removed. 2A and 2B show a state where the contact portion 4 is open.

As shown in FIGS. 3A to 3D, the container body 1 is configured by connecting a body 10 and a cover 11 to each other. Each of the body 10 and the cover 11 is formed in a box shape having one surface opened in the width direction (left-right direction in FIG. 3B) by an insulating synthetic resin. Inside the container 1, the

terminal portions

2 and 3, the contact portion 4, the link mechanism 5, the trip mechanism 6, and the arc extinguishing device 7 are accommodated.

The first terminal portion 2 is provided at one end (left end in FIG. 2A) in the longitudinal direction of the container 1, and is connected to an electric wire (not shown) for connecting to a load (not shown). The 2nd terminal part 3 is provided in the other end (right end in FIG. 2A) of the longitudinal direction of the container 1, and the electric wire (not shown) for connecting with an external power supply (not shown) is connected. As shown in FIGS. 2A and 2B, each of the

terminal portions

2 and 3 includes

terminal fittings

20 and 30 and

terminal screws

21 and 31, respectively. Each of the

terminal fittings

20 and 30 is formed in a rectangular tube shape with the left-right direction in FIG. 2A as the axial direction using a conductive metal plate. That is, the

terminal fittings

20 and 30 are so-called pillar terminals. By inserting one end of the electric wire into the

terminal fittings

20 and 30 and fastening the

terminal screws

21 and 31, the electric wire can be connected to the

terminal portions

2 and 3.

2A and 2B, the contact portion 4 includes a fixed contact 40 and a movable contact 41 that contacts and separates from the fixed contact 40. The fixed contact 40 is fixed to the fixed contact plate 42. The fixed contact plate 42 is made of a low resistance material such as copper. The fixed contact plate 42 is curved when viewed from the width direction of the container body 1 so as to cover one of the assembly screws 12 used when the body 10 and the cover 11 are coupled (see FIG. 2A). The movable contact 41 is provided at one end of an arm 43 formed by punching and bending a metal plate. The arm 43 is rotatable between a position where the movable contact 41 contacts the fixed contact 40 and a position where the movable contact 41 separates from the fixed contact 40 with a shaft 43A provided at the other end as a fulcrum. . One end of the first braided wire 44 is fixed to an intermediate portion of the arm 43. The other end of the first braided wire 44 is fixed to an intermediate portion of a bimetal plate 610 described later.

The link mechanism 5 opens and closes the contact portion 4 according to an opening / closing operation (on / off operation). The structure of such a link mechanism 5 is well known, but will be briefly described below. As shown in FIGS. 2A and 2B, the link mechanism 5 includes a handle 50 and a plurality of link members 51. The handle 50 is rotatably supported by the body 10 in a state where the operation knob 50A protrudes outside from a window hole 2A provided in the front wall (the upper wall in FIG. 2A) of the body 10. Each link member 51 connects the handle 50 and the arm 43, and interlocks the arm 43 with the rotation operation of the handle 50. The handle 50 is rotatable between an on position where the contact portion 4 is closed and an off position where the contact portion 4 is opened.

When the trip mechanism 6 detects an abnormal current (short-circuit current or overload current), the trip mechanism 6 drives the link mechanism 5 to forcibly open (that is, trip) the contact portion 4. The configuration of the trip mechanism 6 is well known, but will be briefly described below. The trip mechanism 6 includes an electromagnetic trip device 60 and a thermal trip device 61, as shown in FIGS. 2A and 2B.

As shown in FIGS. 2A and 2B, the electromagnetic trip device 60 includes a coil 60A, a fixed iron core (not shown), a movable iron core (not shown), a return spring (not shown), and a pin 60B. And the yoke 60C. The coil 60A is configured by winding a rectangular copper wire around the outer peripheral surface of the coil bobbin 60D. The coil bobbin 60D is formed in a cylindrical shape from an insulating synthetic resin. One end of the coil 60 A is connected to the terminal fitting 20 of the first terminal portion 2, and the other end is connected to the fixed contact plate 42. The fixed iron core is made of a magnetic material and is housed inside the coil bobbin 60D. The movable iron core is made of a magnetic material and is slidably arranged between a position in contact with the fixed iron core and a position away from the fixed iron core in the coil bobbin 60D. The return spring is made of, for example, a coil spring, and is housed between the movable iron core and the fixed iron core in the coil bobbin 60D. The return spring bends when the movable iron core moves in a direction in contact with the fixed iron core, and generates an elastic force that moves the movable iron core in a direction away from the fixed iron core. The pin 60B is coupled to the movable iron core, and its tip protrudes outside the coil bobbin 60D. And the pin 60B is comprised so that the front-end | tip may interlock | cooperate with a part of link member 51, when a movable iron core is attracted | sucked by a fixed iron core. The yoke 60C is made of a magnetic material. As shown in FIG. 2A, the yoke 60 C is formed to be curved as viewed from the width direction of the container body 1 so as to cover the periphery of the coil bobbin 60 D.

The thermal tripping device 61 is composed of a bimetal plate 610 as shown in FIGS. 2A and 2B. As the bimetal plate 610, a direct heating type that curves by self-heating, or an indirectly heated type that curves by heating by a heater can be used. One end of the bimetal plate 610 is configured to interlock with a part of the link member 51 when the bimetal plate 610 is curved. One end of the second braided wire 45 is fixed to the other end of the bimetal plate 610. The other end of the second braided wire 45 is connected to the terminal fitting 30 of the second terminal portion 3.

The arc extinguishing device 7 is a device for quickly extinguishing the arc A1 (see FIG. 4) generated when the contact portion 4 is opened. The arc extinguishing device 7 includes an arc travel plate 70 and an arc extinguishing grid 71 as shown in FIGS. 2A and 2B. The arc traveling plate 70 is formed by bending a strip-shaped metal plate. One end of the arc traveling plate 70 on the right side in FIG. 2A is coupled to one end of the bimetal plate 610. The arc traveling plate 70 extends along the lower wall in FIG. 2A in the container 1 to the left side in FIG. 2A of the container 1. The arc extinguishing grid 71 includes a plurality of (12 in FIG. 2A) arc extinguishing plates 710 and two (1 in FIG. 2A) support plates 711. Each arc extinguishing plate 710 is formed of a conductive material. Each arc-extinguishing board 710 is arrange | positioned in parallel along the height direction (up-down direction in FIG. 2A) of the container 1 at intervals. Each support plate 711 is made of an insulating material. Each support plate 711 covers both sides of each arc-extinguishing plate 710 in the width direction (direction perpendicular to the paper surface in FIG. 2A).

Hereinafter, the operation of the arc extinguishing device 7 will be briefly described with reference to FIG. When the arc A1 is generated when the movable contact 41 leaves the fixed contact 40, an arc current flows through the fixed contact plate 42 and the arc traveling plate 70 via the arc A1, and a magnetic field is generated by the arc current. By this magnetic field, a Lorentz force acts on the arc A1, and the arc A1 is extended and is induced to the left side in FIG. That is, the fixed contact plate 42 and the arc traveling plate 70 guide an arc generated between the contacts (between the movable contact 41 and the fixed contact 40) in a direction away from the contact by the action of an electromagnetic field. The arc extinguishing grid 71 divides the induced arc A 1 by a plurality of arc extinguishing plates 710. Thereby, since a high arc voltage arises, it can suppress and suppress a short circuit current.

Hereinafter, the operation of the link mechanism 5 will be briefly described. When the handle 50 is rotated to the on position, each link member 51 is interlocked with the handle 50. As a result, the arm 43 rotates clockwise around the shaft 43A, and the movable contact 41 comes into contact with the fixed contact 40 (that is, the contact portion 4 is closed). As a result, the electric path is routed through the path of the terminal fitting 20, the coil 60A, the fixed contact plate 42, the fixed contact 40, the movable contact 41, the arm 43, the first braided wire 44, the bimetal plate 610, the second braided wire 45, and the terminal fitting 30. Formed and energized. At this time, the movable contact 41 is pressed in a direction toward the fixed contact 40 by an elastic force of a contact pressure spring (not shown). Thereby, the contact pressure with respect to the fixed contact 40 of the movable contact 41 is large.

Thereafter, when the handle 50 is rotated to the off position, each link member 51 is interlocked with the handle 50. As a result, the arm 43 rotates counterclockwise about the shaft 43A, and the movable contact 41 is separated from the fixed contact 40 (that is, the contact portion 4 is opened). Thereby, the electric circuit formed between each

terminal part

2 and 3 is open | released, and electricity supply is cancelled | released.

Next, the operation of the trip mechanism 6 will be briefly described. First, the operation of the electromagnetic trip device 60 will be described. In a state where no current flows through the coil 60A (initial state), the movable iron core is separated from the fixed iron core by the elastic force of the return spring. For this reason, the pin 60 B connected to the movable iron core is retracted to a position not interlocked with a part of the link member 51.

When a current flows between the

terminal portions

2 and 3 and the coil 60A is energized, the magnetic resistance of the magnetic path passing through the fixed core, the yoke 60C, and the movable core is reduced between the movable core and the fixed core. A suction force acts. When the current flowing through the coil 60A is an excessive current such as a short circuit current, the movable iron core moves to the fixed iron core against the elastic force of the return spring. At this time, the pin 60B connected to the movable iron core protrudes rightward in FIG. When the trip operation is performed and the contact portion 4 is forcibly opened, the current flowing through the coil 60A is reduced and the attractive force acting on the movable iron core is reduced. Then, the movable iron core is moved to the initial position by the elastic force of the return spring, and the pin 60B is also retracted to the initial position.

Next, the operation of the thermal tripping device 61 will be described. In a state where no current flows through the bimetal plate 610 (initial state), the bimetal plate 610 is not curved and the bimetal plate 610 is not interlocked with a part of the link member 51. On the other hand, when an excessive current such as an overload current flows between the

terminal portions

2 and 3, the temperature of the bimetal plate 610 rises due to the excessive current, and the bimetal plate 610 is bent. Thereby, the bimetal plate 610 is interlocked with a part of the link member 51, and the trip operation by the link mechanism 5 is performed. When the trip operation is performed and the contact portion 4 is forcibly opened, the current flowing through the bimetal plate 610 decreases. Then, the temperature of the bimetal plate 610 decreases, the degree of curvature decreases, and eventually the bimetal plate 610 returns to the initial state where it does not interlock with a part of the link member 51.

Hereinafter, the principle that the arc A1 generated between the contacts is guided to the arc extinguishing grid 71 will be briefly described. In the following description, as shown in FIG. 5, it is assumed that the fixed contact plate 42 and the arc traveling plate 70 are both long flat plates and are arranged in parallel to each other. Further, it is assumed that the arc A1 is cylindrical as shown in FIG.

When the arc A1 occurs between the contacts, the fixed contact plate 42 and the arc traveling plate 70 are short-circuited by the arc A1, as shown in FIG. The arc current I1 flows through the fixed contact plate 42, the arc A1, and the arc traveling plate 70. Due to the arc current I1, a magnetic field B1 along the circumferential direction of the arc current I1 is generated on the fixed contact plate 42. Similarly, a magnetic field B2 along the circumferential direction of the arc current I1 is generated in the arc A1. Further, the arc traveling plate 70 generates a magnetic field B3 along the circumferential direction of the arc current I1.

As shown by the arrows in FIGS. 6A and 6B, the Lorentz force toward the central axis of the arc A1 acts on the arc A1. 6A and 6B, the thicker the arrow, the greater the Lorentz force, and the thinner the arrow, the smaller the Lorentz force. The Lorentz force acting on the arc A1 is determined by the length of the current path of the arc A1, the arc current I1, and the magnetic flux density of the magnetic flux interlinking with the arc current I1.

In the first region on the right side of the arc A1 shown in FIG. 6B, the magnetic field B1, B3 generated in each of the fixed contact plate 42 and the arc traveling plate 70 causes the arc to be compared with the second region on the left side shown in FIG. 6B. The magnetic flux density of the magnetic flux interlinking with the current I1 is increased. Therefore, as shown in FIG. 6A, the left-handed first Lorentz force F1 in FIG. 6 is larger than the right-handed second Lorentz force F2 in FIG. Lorentz force F3 works. The arc A1 is guided to the arc extinguishing grid 71 by the third Lorentz force F3.

In order to quickly guide the arc A1 to the arc extinguishing grid 71, the third Lorentz force F3 may be increased. In order to increase the third Lorentz force F3, the magnetic flux density of the magnetic flux interlinking with the arc current I1 in the first region should be increased. Therefore, in the circuit breaker 100 of this embodiment, as shown in FIG. 1, the magnetic body 8 electrically insulated from the fixed contact plate 42 is disposed around the fixed contact plate 42 in the vicinity of the fixed contact plate 42. It arrange | positions so that the generated magnetic field B1 may pass.

Hereinafter, a model of the fixed contact plate 42 and the arc traveling plate 70 and a model of the magnetic body 8 are created, and it is assumed that the arc A1 is generated between the end of the fixed contact plate 42 and the arc traveling plate 70. The result of the electromagnetic field analysis using the element method is shown. First, a model used for electromagnetic field analysis will be described. As shown in FIG. 1, the fixed contact plate 42 and the arc traveling plate 70 are designed based on the actual shape of the circuit breaker 100 (see FIGS. 2A and 4).

The fixed contact plate 42 was designed with copper, which is a nonmagnetic material. The arc traveling plate 70 was designed with iron (here, SPCC (cold rolled steel plate)) which is a magnetic material. In the vicinity of the back surface of the fixed contact plate 42 (that is, the surface opposite to the surface on which the arc travels in the fixed contact plate 42), a first magnetic body 80 is disposed as a magnetic body. That is, the first magnetic body 80 is disposed on the side opposite to the side where the fixed contact 40 is provided in the thickness direction of the fixed contact plate 42. The first magnetic body 80 is made of iron (here, SPCC (cold rolled steel plate)), which is a magnetic material, and is designed as a flat plate as shown in FIG. 1B. The first magnetic body 80 was disposed at a certain distance from the back surface of the fixed contact plate 42. Therefore, the first magnetic body 80 is electrically insulated from the fixed contact plate 42.

The second magnetic body 81 and the third magnetic body 82 are disposed as magnetic bodies on both sides of the fixed contact plate 42 and the arc traveling plate 70 along the short (width) direction, respectively. Each of the second magnetic body 81 and the third magnetic body 82 is made of iron (here, SPCC (cold rolled steel plate)), which is a magnetic material, and is designed as a flat plate as shown in FIG. The second magnetic body 81 and the third magnetic body 82 are both arranged with a fixed distance from the fixed contact plate 42 and the arc traveling plate 70. Accordingly, the

magnetic bodies

81 and 82 are electrically insulated from both the fixed contact plate 42 and the arc traveling plate 70.

Moreover, in the circuit breaker 100 of this embodiment, as shown in FIGS. 1 and 4, the assembly screw 12 is provided so as to be covered with the fixed contact plate 42. The assembly screw 12 is made of iron, which is a magnetic material. (Here, SPCC (cold rolled steel plate)).

Hereinafter, a model obtained by removing the first magnetic body 80 and the assembly screw 12 from the model shown in FIG. 1 is referred to as a “basic model”. As a result of electromagnetic field analysis using this basic model, the third Lorentz force F3 acting on the arc A1 was 4.319N. Next, as a result of performing an electromagnetic field analysis using a model in which the assembly screw 12 is added to the basic model, the third Lorentz force F3 acting on the arc A1 is 5.343 N, which is 23.7% larger than the basic model. Further, as a result of conducting an electromagnetic field analysis using a model (model shown in FIG. 1) in which the first magnetic body 80 and the assembly screw 12 are added to the basic model, the third Lorentz force F3 acting on the arc A1 is 5.481 N, which is the basic model. 26.9% larger than

As described above, in the circuit breaker 100 of the present embodiment, the first magnetic body 80 is disposed as the magnetic body 8 so that the magnetic field B1 generated around the fixed contact plate 42 passes. For this reason, the magnetic field B1 is increased, and the magnetic flux density of the magnetic flux interlinking with the arc current I1 in the first region is also increased. Therefore, in the circuit breaker 100 of this embodiment, the Lorentz force (third Lorentz force F3) acting on the arc A1 can be increased, and the arc A1 generated between the contacts can be quickly guided to the arc extinguishing grid 71. Can do. In other words, the circuit breaker 100 of the present embodiment can guide the arc A1 generated between the contacts so as to be quickly away from the contacts.

In particular, in the circuit breaker 100 of the present embodiment, the assembly screw 12 used for coupling the body 10 and the cover 11 to each other is formed of a magnetic material. That is, the assembly screw 12 also serves as the magnetic body 8. For this reason, since it is not necessary to newly provide the space for arrange | positioning the magnetic body 8, the enlargement of the circuit breaker 100 can be avoided.

Furthermore, in the circuit breaker 100 of the present embodiment, the second magnetic body 81 and the third magnetic body 82 are provided on both sides of the fixed contact plate 42 in the width direction (direction perpendicular to the paper surface in FIG. 2A) as the magnetic body 8, respectively. It is arranged. The width direction of the fixed contact plate 42 is also a direction parallel to the axial direction of the assembly screw 12. In other words, in the circuit breaker 100 of the present embodiment, the second magnetic body 81 and the third magnetic body 82 are arranged so that the magnetic field B2 generated around the arc A1 passes when the arc A1 occurs. Yes. For this reason, the magnetic field B2 can be strengthened, and the magnetic flux density of the magnetic flux interlinking with the arc current I1 in the first region can be increased. Therefore, by arranging the

magnetic bodies

81 and 82, the Lorentz force acting on the arc A1 can be increased, and the arc A1 generated between the contacts can be more quickly guided to the arc extinguishing grid 71.

In addition, in the circuit breaker 100 of this embodiment, although iron is used as the material of the magnetic body 8, the magnetic body 8 may be formed from other magnetic materials.

Further, the circuit breaker 100 of this embodiment is configured to guide the arc A1 to the arc extinguishing grid 71, but may be configured not to include the arc extinguishing grid 71. For example, even when an arc extinguishing space for escaping the arc A1 is provided instead of the arc extinguishing grid 71, the circuit breaker 100 of this embodiment can quickly guide the arc A1 to the arc extinguishing space. it can.

Moreover, the circuit breaker 100 of this embodiment can be used as both an AC circuit breaker and a DC circuit breaker. When the circuit breaker 100 of the present embodiment is used as a DC circuit breaker, the second magnetic body 81 and the third magnetic body 82 may be configured with permanent magnets magnetized in a specific direction.

As described above, the circuit breaker 100 of the present embodiment has the following first feature.

In the first feature, the circuit breaker 100 of the present embodiment includes a fixed contact plate 42 and a magnetic body 8. The fixed contact plate 42 has a fixed contact 40 that is in contact with and away from the movable contact 41, and the direction in which the arc A1 generated between the movable contact 41 and the fixed contact 40 is moved away from the movable contact 41 and the fixed contact 40 by the action of an electromagnetic field. To guide. The magnetic body 8 is disposed in the vicinity of the fixed contact plate 42 and is electrically insulated from the fixed contact plate 42. And the magnetic body 8 is arrange | positioned so that the magnetic field B1 produced around the fixed contact plate 42 may pass.

In other words, the circuit breaker 100 according to the present embodiment is disposed in the vicinity of the fixed contact plate 42 having the fixed contact 40 that contacts and separates from the movable contact 41, and is electrically connected to the fixed contact plate 42. A magnetic body 8 to be insulated and a container body 1 for housing the fixed contact plate 42 are provided. The fixed contact plate 42 guides an arc A1 generated between the movable contact 41 and the fixed contact 40 in a direction away from the movable contact 41 and the fixed contact 40 by the action of an electromagnetic field. The container body 1 is configured by connecting a plurality of members (body 10 and cover 11) to each other by an assembly screw 12. And the magnetic body 8 is arrange | positioned so that the magnetic field B1 produced around the fixed contact plate 42 may pass. Further, the assembly screw 12 also serves as the magnetic body 8.

Further, the circuit breaker 100 of the present embodiment may have the following second feature in addition to the first feature.

In the second feature, the magnetic body 8 is arranged so that the magnetic field B2 generated around the arc A1 passes therethrough.

According to the present embodiment described above, in the present invention, the magnetic body 8 is arranged so that the magnetic field B1 generated around the fixed contact plate 42 passes. Therefore, according to the present invention, the Lorentz force (third Lorentz force F3) acting on the arc A1 generated between the contacts can be increased, and the arc A1 can be guided to be quickly moved away from the contacts.

Claims

A fixed contact plate that has a fixed contact that contacts and separates from the movable contact, and that induces an arc generated between the movable contact and the fixed contact in a direction away from the movable contact and the fixed contact by the action of an electromagnetic field;
A magnetic body disposed in the vicinity of the fixed contact plate and electrically insulated from the fixed contact plate;
A container that houses the fixed contact plate,
The container is configured by connecting a plurality of members to each other by an assembly screw,
The magnetic body is arranged so that a magnetic field generated around the fixed contact plate passes through,
The circuit breaker characterized in that the assembly screw also serves as the magnetic body.
The circuit breaker according to claim 1, wherein the magnetic body is arranged so that a magnetic field generated around the arc passes therethrough.