JPH0498726A - Circuit breaker - Google Patents

Abstract

PURPOSE:To prolong a lifetime of contacts by generating a preceding arc in closing and an arc in breaking individually on separate contacts in a single breaker. CONSTITUTION:When a movable element 2 is in a closed position, a movable electrode 11 is kept in a retracted position. In this state, when the element 2 is driven, a movable arc contact 201 is separated from a fixed arc contact 101 so that an arc is generated between both the arc contacts. Accordingly, no arc is generated between the movable electrode 11 and a fixed contact portion 9. When the movable element reaches a breaker position, the electrode 11 is positioned in an advance position. When the element 2 is moved from the breaker position toward the closed position, a preceding arc is generated between the electrode 11 and the contact portion 9 so that the contact 201 is brought into contact with the contact 101 without any arc. When the movable element reaches the closed position, the electrode 11 is positioned in the retracted position. Therefore, it is possible to prolong a lifetime of a breaker which is frequently switched.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power circuit breaker suitable for use in frequently opened and closed applications such as phase adjustment equipment.

[Prior Art] Generally, a power circuit breaker is provided with a fixed arc contact on the fixed element side and a movable arc contact on the movable element side, and between these arc contacts, an arc is generated during breaking and closing. I am trying to generate this.

FIG. 8 shows the structure of the interrupting section of a conventional gas circuit breaker. In the figure, 1 is a fixed element and 2 is a movable element. The upper half of FIG. 8 shows the movable element 2 in the closing position, and the lower half shows the movable element in the blocking position.

The fixed element 1 includes a fixed main circuit conductor 100, a fixed arc contact 101, a fixed main contact 102, and a shield 103, and the main circuit conductor 100 is connected to an external terminal (not shown).

The movable element 2 includes a movable arc contact 201, a movable main contact 202, a buffer cylinder 203, and an insulating nozzle 20.
4 and a movable conductor shaft 205, the buffer cylinder 20
A buffer piston 301 is fitted within the buffer piston 3. The buffer piston 301 is provided integrally with the movable main circuit conductor 3 attached to a fixed location, and an external terminal (not shown) is connected to the main circuit conductor 3. The buffer piston 301 is provided with a ventilation hole 302 .
A check valve 4 is attached to 02. Movable conductor shaft 205
A current collecting contact 5 is provided between the main circuit conductor 3 and the movable conductor shaft 205 via this current collecting contact.
electrically connected to.

The above-mentioned interrupting section is housed in a circuit breaker container (not shown) filled with SF6 gas, and the movable conductor shaft 205 is connected to the insulated operating rod 6.
It is connected to an operating device (not shown) via a connection mechanism including.

In the circuit breaker described above, when the movable conductor shaft 205 is driven to the left in the drawing by an operator (not shown) from the cut-off state shown in the lower half of FIG.
01 contacts the fixed arc contact 101, and then the movable main contact 202 contacts the fixed main contact 102, resulting in the closed state shown in the upper half of FIG. In this way, when turning on, the movable arc contactor 201 contacts the fixed arc contactor 101, and then the movable main contactor 202 contacts the fixed main contactor 101.
Therefore, the arc at the time of turning on occurs mostly between the movable arc contact 201 and the fixed arc contact 101, and the movable main contact 202 is arc-free and the arc is generated between the fixed main contact 102 and the movable main contact 202.
come into contact with. In addition, during the process of the above input operation,
As the volume inside the buffer cylinder 203 expands,
SF6 gas flows into the cylinder through the check valve 4.

When the movable conductor shaft 205 is driven rightward in the drawing by an operating device (not shown) from the closed state shown in the upper half of FIG. Then, the movable arc contact 201 separates from the fixed arc contact 101. When the movable arc contact 201 separates from the fixed arc contact 101, an arc is generated between both arc contacts, but during the shutoff process, the check valve 4 closes and the volume inside the puffer cylinder 203 is reduced by the piston 301. As the pressure within the cylinder is increased, the SF6 gas within the cylinder is blown from the insulating nozzle 204 onto the arc. Therefore SF
The arc is cooled by the cooling effect of the 6 gas and extinguished at the zero point of the current.

[Problems to be Solved by the Invention] As mentioned above, in conventional circuit breakers, both the arc at the time of closing and the arc at the time of disconnection are generated between the same arc contacts, so that the arc of the arc contact Durability is ensured by using arc-resistant metal on exposed parts.

However, in cases where the circuit breaker used for switching on and off phase adjustment equipment is frequently opened and closed and a preceding arc is generated at the time of closing, it is recommended to use a common arc contactor to generate the arc at the time of closing and closing. However, there was a problem in that the arc contactor was severely worn out and the life of the circuit breaker was shortened.

In order to eliminate the above-mentioned inconvenience, the receiver can interrupt the main circuit current by installing two circuit breakers in parallel and making the operating order of the two circuit breakers different when closing and disconnecting. In the arc contact of the circuit breaker, measures are taken to prevent the generation of a preceding arc at the time of closing. However, in this case, an extra circuit breaker is required and the operation sequence of the circuit breaker is complicated, which increases the equipment cost and is uneconomical.

An object of the present invention is to provide a circuit breaker in which the life of the contact is extended by generating a preceding arc at the time of closing and an arc at the time of breaking using separate contacts. There is a particular thing.

[Means for Solving the Problem] The present invention includes a fixed element having a fixed arc contact, a closing position having a movable arc contact, and a state where the movable arc contact is in contact with the fixed arc contact. In a circuit breaker, the circuit breaker is provided with a movable element that is displaceable between a breaking position where the movable arc contact is separated from the fixed arc contact by a predetermined insulated distance, and a movable element that is displaceable between The preceding arc and the arc at the time of interruption are generated by separate contacts.

In the present invention, the movable element or the movable electrode for firing at the time of closing can be displaced relative to the movable arc contact between a retracted position and an advanced position closer to the fixed element side than the retracted position. The fixed element is provided with a fixed contact portion for firing at the time of closing, which brings the movable electrode into contact or at least close to a distance where firing is possible at the time of closing.

Further, in the present invention, first and second movable electrode drive means are provided for moving the movable electrode to the retracted position and the forward position, respectively.

The first movable electrode driving means acts on the movable electrode in the process of displacing the movable element toward the closing position, and displaces the movable electrode to the retracted position after the movable arc contactor contacts the fixed arc contactor.

Further, the second movable electrode driving means acts on the movable electrode during the process in which the movable element is displaced toward the cutoff position, and displaces the movable electrode to the forward position after the movable arc contact is separated from the fixed arc contact.

In the present invention, the forward position and the backward position are set so as to satisfy the relationship shown below.

That is, in the process of moving the movable element toward the closing position with the movable electrode in the forward position, the distance between the movable arc contactor and the fixed arc contactor reaches a distance that allows firing. The forward position is set so that the distance between the firing fixed contact part and the firing fixed contact part is a distance that allows firing.

In addition, when the movable element is displaced to the cutoff position with the movable electrode in the retracted position, the distance between the movable electrode and the fixed arc firing contact part at the time of closing before the movable arc contactor separates from the fixed arc contactor. The evacuation position is set so that the distance is such that it cannot be fired.

The fixed element and the movable element each further include a fixed main contact and a movable main contact, and after the movable main contact is separated from the fixed main contact during the breaking process, the movable arc contact is connected to the fixed arc contact. When the positional relationship of the contacts is set so that they are separated from each other, the tip of the shield that covers the fixed main contact can be used as the firing contact at the time of closing. In this case, the movable electrode can also serve as a contact portion of the movable main contactor.

Alternatively, the tip of the fixed arc contact may be used as the fixed contact for firing at the time of closing, and the movable electrode may be provided concentrically with the movable arc contact.

C Effect: With the above configuration, when the circuit breaker is closed, the movable electrode for firing at the time of closing has been moved to the forward position by the second movable electrode drive means in the process of the previous circuit breaking operation.
Before the distance between the movable arc contact and the fixed arc contact reaches a distance that allows arcing, the distance between the movable electrode and the fixed contact portion for arcing at the time of closing becomes a distance that allows arcing. Therefore,
As the movable element approaches the fixed element,
First, a preceding arc is generated between the movable electrode for firing at the time of closing and the fixed contact portion for firing at the time of closing, and then the movable arc contactor contacts the fixed arc contactor without arcing.

In addition, at the time of disconnection, since the movable electrode was moved to the retracted position by the first movable electrode drive means during the previous closing operation, the movable electrode separates from the fixed contact part and the distance between them becomes such that firing is impossible. After the distance is reached, the movable arc contact moves away from the fixed arc contact. Therefore, at the time of interruption, an arc always occurs between the movable arc contact and the fixed arc contact, and no arc occurs between the movable electrode and the fixed contact.

As described above, in the present invention, in addition to the fixed arc contact and the movable arc contact, a movable electrode for firing at the time of closing, a fixed contact portion for firing at the time of closing, and the breaking operation and closing operation of the circuit breaker are provided. A driving means for displacing the movable electrode between a forward position and a backward position in accordance with the closing of the circuit breaker is provided, and when the circuit breaker is closed, the movable electrode for firing at the time of closing is positioned in the forward position, so that the movable electrode and the fixed contact are By generating a leading arc between the movable arc contactor and the fixed arc contactor, and by placing the movable electrode for firing at the time of closing in the retracted position at the time of shutoff, an arc is generated between the movable arc contactor and the fixed arc contactor. Therefore, the life of the contacts, especially the life of the arc contacts that interrupt the main circuit current, can be extended, and the life of circuit breakers that are frequently opened and closed can be extended.

[Examples] Examples of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1 shows an embodiment in which the present invention is applied to a circuit breaker of the type shown in Fig. 8. In Fig. 1, the same parts as those in Fig. 8 are given the same reference numerals. be. Further, in FIG. 1, the upper half shows the on state, and the lower half shows the off state.

The main circuit conductor 100 of the fixed element 1 is formed into a cylindrical shape and is fixed to one end inside a circuit breaker container (not shown). The fixed arc contact 101 is made of a rod-shaped conductor and is provided at the center of the main circuit conductor 100 so as to share an axis with the main circuit conductor. The fixed main contact 102 includes a large number of finger-shaped contact pieces 102a arranged side by side on the outer periphery of the peripheral wall 100a of the main circuit conductor 100 and a holding spring 10.
2b and a contact spring 102c, and a shield 103 is provided to cover the tulip contact.

In this example, the peripheral wall portion 100a of the main circuit conductor 100 is extended toward the movable element 2, and the tip of the peripheral wall portion 100a is disposed close to the tip of the fixed main contact 102,
The tip of the peripheral wall portion 100a serves as the first movable electrode driving means 8. Further, the tip of the shield 103 serves as a fixed contact portion 9 for firing at the time of closing. It is preferable that the contact portion 9 is formed of an arc-resistant metal or a similar material having arc-resistant properties.

The main circuit conductor 3 on the movable element side consists of a cylindrical body having a cylindrical first circumferential wall part 3A and a second circumferential wall part 3B concentrically, and a buffer piston 30 is provided at the tip of the inner circumferential wall part 3A.
1 is provided. The piston 301 has a ventilation hole 302
is provided, and a check valve 4 is attached to the vent hole.

The tip of the outer circumferential wall 3B of the main circuit conductor 3 is a piston 30.
1, and the tip of this peripheral wall portion 3B is used as the second movable electrode driving means 10.

A nozzle portion 206 is provided on the movable element side of the buffer cylinder 203, and an insulating nozzle 204 is attached to the tip of the nozzle portion. A cylindrical contact holding conductor 207 is provided inside the nozzle portion 206, and a movable arc contact 201 made of arc-resistant metal is mounted on the conductor 207.
is installed. The contact holding conductor 207 is connected to the connecting portion 2
08 to the nozzle part 206, and the annular gas passage around the contact holding conductor 207 and the movable arc contact 201 is connected to the gas space in the cylinder 203 through a number of vent holes provided in the connecting part 208. has been done.

A hollow movable conductor shaft 205 is connected to the contact holding conductor 207, and the movable conductor shaft 205 passes through a hole provided in the center of the piston 301 and is inserted inside the main circuit conductor 3. A current collector contact 5 is attached to a boss provided at the center of the piston 301, and the movable conductor shaft 205 and the main circuit conductor 3 are electrically connected via the contact.

The movable conductor shaft 205 is connected to an operation device (not shown) via a connection mechanism including an insulated operation rod 6.

A cylindrical surface is formed on the outer periphery of the nozzle portion 206, and the cylindrical movable electrode 11 for firing at the time of injection is slidably fitted into the cylindrical surface. A flange lla is provided at the end of the movable electrode 11 on the side of the main circuit conductor 3, and has a size capable of coming into contact with the second movable electrode driving means 10, and when the movable element 2 moves to the cutoff position side, In the final process of the breaking operation after the movable arc contact 201 is separated from the fixed arc contact 101, the flange lla comes into contact with the second movable electrode drive means 10, and the movable electrode 11 is moved as shown in the lower half of FIG. It is designed so that it can be displaced to a forward position.

In this way, in the process of moving the movable element 2 toward the fixed element 1 with the movable electrode 11 in the forward position, the shortest distance between the movable arc contact 201 and the fixed arc contact 101 is the distance that allows firing. The forward position of the movable electrode is set so that the distance between the movable electrode 11 and the fixed contact portion 9 for firing at the time of closing becomes a distance that allows firing.

Further, when the movable element is displaced to the closing position side, after the movable arc contactor 201 contacts the fixed arc contactor 101, the tip of the movable electrode 11 is pushed by the first movable electrode drive means 8, and the movable electrode 11 is It can be displaced to the retracted position shown in the upper half of FIG.

In this way, in the process in which the movable element is displaced toward the cutoff position with the movable electrode 11 in the retracted position, the movable electrode 11 and the fixed contact part 9 are connected before the movable arc contact 201 separates from the fixed arc contact 101. The retracted position of the movable electrode is set such that the shortest distance between them is a distance that does not allow firing.

In order to position and hold the movable electrode 11 in the forward and backward positions, two grooves 211 and 212 are provided in the cylindrical surface of the nozzle portion 206 at a distance in the axial direction, and grooves 211 and 212 are provided in the peripheral wall of the movable electrode 11 in the circumferential direction. A large number of holes 11b are provided at equal intervals. A large number of finger-shaped contacts 12 are arranged around the outer periphery of the movable electrode 11, and each contact 12
A protrusion provided at one end is brought into contact with the cylindrical surface of the nozzle portion 206 through the hole 11b. Finger contact 1
2,12. ... are urged by the ring-shaped spring 13 and pressed toward the nozzle portion 206, and the movable electrode 11 is moved to the forward position and the forward position, respectively, with the protrusion at one end of each contactor 12 fitted into the grooves 211 and 212, respectively. It is designed to be positioned and held in the retracted position. Contactor 12 and spring 13
This constitutes a holding device for the movable electrode.

Next, the operation of the circuit breaker will be explained. As shown in the upper half of FIG. 1, when the movable lument 2 is in the closing position, the protrusion of the contactor 12 constituting the movable electrode holding device is inserted into the groove 2.
12, and the movable electrode 11 is held in the retracted position. The movable electrode 11 also serves as a movable main contact and contacts the fixed main contact 102 from the inside. At this time, main circuit conductor 101 - fixed main contact 102 - movable electrode 1
1 - Nozzle part 206 - Movable conductor shaft 205 - Current collector contact -
A main circuit current flows through the path of the main circuit conductor 3.

When the movable element 2 is driven to the left in the drawing from this state, the movable electrode 11 first separates from the fixed main contact 102, and then the movable arc contact 201 moves away from the fixed main contact 102.
Leave 01. As shown in the upper half of FIG. 2, when the movable arc contact 201 separates from the fixed arc contact 101, an arc A is generated between both arc contacts. When the movable arc contact 201 separates from the fixed arc contact, the distance between the tip of the movable electrode 11 and the fixed contact part 9 has already become a distance that makes it impossible to fire an arc. 9, no arc will occur between the two. In the process of displacing the movable element toward the cutoff position, the volume inside the buffer cylinder 203 is reduced, and the S inside the cylinder 203 is reduced.
Since the F6 gas is blown onto the arc A from the insulating nozzle 204, the arc is cooled and extinguished at the zero point of the current.

Just before the movable element reaches the cutoff position, the movable electrode 11
Since the flange lla contacts the second movable electrode drive means 10, the movable electrode 11 is moved toward the fixed element 1 relative to the movable arc contactor 201. When the movable element reaches the blocking position, the protrusion of the contact 12 fits into the groove 211, as shown in the lower half of FIG.
The movable electrode 11 is positioned at the forward position.

When the movable element 2 is moved from the blocking position to the closing position, since the movable electrode 11 is in the forward position, the distance between the movable arc contact 201 and the fixed arc contact 101 becomes a distance that allows firing. Before the distance between the movable electrode 11 and the fixed contact part 9 reaches a distance that allows arcing, a preceding arc occurs between the movable electrode 11 and the fixed contact part 9, as shown in the lower half of FIG. A- occurs. Next, the movable electrode 11 subsequently contacts the fixed contact portion 9 and the fixed main contact 102 . After the movable electrode 11 contacts the fixed contact portion 9, a movable arc contact occurs, and the movable electrode 201 contacts the fixed arc contact 101 without an arc. After the movable electrode 11 contacts the fixed main contact 102, the tip of the movable electrode 11 is connected to the first movable electrode driving means 8.
The movable electrode is moved toward the cutoff position relative to the movable arc contactor 201. When the movable element reaches the closing position, the protrusion of the contact 12 enters the groove 212.
The movable electrode 11 is positioned at the retracted position.

As described above, in the circuit breaker of the present invention, an arc is generated between the movable electrode and the fixed contact part when closing, and an arc is generated between the movable arc contact and the fixed arc contact when disconnected. It is possible to reduce wear and tear on the movable arc contactor and fixed arc contactor, and to extend the life of a circuit breaker that is frequently opened and closed.

In the above embodiment, as shown in FIG. 5, an arc A- is generated between the movable electrode 11 and the fixed contact portion at the tip of the shield 103 when the movable electrode 11 is turned on. There is a risk that the surface near the tip may become rough.Since the movable electrode 11 also serves as a movable main contact, if the surface becomes rough, the current carrying performance may be affected.

FIGS. 6 and 7 show an example of means for solving the above problem. In this example, as shown in FIG. Piece 11c is joined.

The number of arc pieces 11c is the same as the number of contact pieces 102a constituting the fixed main contact 102.
They are arranged in one-to-one correspondence. - A groove 22 into which the arc piece 11c is fitted is formed in the contact portion of the contact piece 102a constituting the blade fixed main contact.

With this configuration, when the movable electrode 11 approaches the fixed contact section 9, an arc A' is generated between the arc piece 11C and the fixed contact section 9. When the movable electrode 11 contacts the fixed contact 102, the arc piece 11c fits into the groove 22, so that the movable electrode 11 and the fixed main contact 102 can be easily brought into contact.

In the above embodiment, the movable electrode was provided to also serve as the movable main contact, but the movable electrode can move between the forward position and the backward position, and when it is in the forward position, the movable arc contact Before approaching the fixed element and generating an arc between the movable arc contact and the fixed arc contact, an arc is generated between the movable arc contact and the fixed contact provided on the fixed element side. (However, the way to set it up is not limited to the above example.

3 and 4 show another embodiment of the present invention. In this embodiment, the tip of the fixed arc contact 101 is used as the fixed contact for firing at the time of closing, and the movable electrode 11
is provided inside the movable arc contactor 201 concentrically with the movable arc contactor. The movable electrode 11 is made of a rod-shaped conductor, and a protrusion 11A is provided on the outer periphery of the movable electrode 11.

The movable electrode 11 is the contact holding conductor 20 of the movable element 2
6 and a hole 215 formed inside the movable conductor shaft 205 so as to be slidable therein. Grooves 211 and 212 into which the protrusion 11A fits are provided around the inner periphery of the hole 215, and as shown in the lower half of FIG. positioned at
As shown in the upper half of the figure, the movable electrode is positioned at the forward position with the protrusion 11A fitted into the groove 211.

Furthermore, a slit h205a is provided that extends in the axial direction through the peripheral wall of the rear end of the movable conductor shaft 205, and a stopper 30 is inserted through this slit 205a. It is supported by the section 303.

In this example, like the circuit breaker shown in FIG. 8, a movable main contactor 202 is provided near the outer periphery of the movable element, and after the movable main contactor 202 is separated from the fixed main contactor 102 at the time of disconnection, the movable main contactor 202 is movable. The positional relationship between the main contact and the arc contact is set so that the arc contact 201 is separated from the fixed arc contact 101.

In this embodiment, the fixed arc contactor 101 also serves as the first movable electrode drive means 8, and the stopper 30 constitutes the second movable electrode drive means 10.

When in the cutoff state, the protrusion 11A of the movable electrode 11 is fitted into the groove 211, and the movable electrode 11 is in the forward position. At this time, as shown in the lower half of FIG. 3, the tip of the movable electrode 11 projects further outward than the tip of the movable arc contactor 201.

As the movable element 2 moves toward the closing position, the tip of the movable electrode 11 and the fixed arc close together before the distance between the tip of the movable arc contact 201 and the fixed arc contact 101 reaches a distance that allows firing. Since the distance between the tip of the contactor 101 (fixed contact part 9 for firing at the time of closing) is a distance that allows firing, the distance between the movable electrode 11 and the movable arc contactor is as shown in the lower half of FIG. 101, an arc A' is generated.

When the movable element further moves to the closing position after the movable electrode 11 contacts the fixed arc contact 101, the movable electrode 11 is pushed by the fixed arc contact 101 and moves to the cut-off position, and the movable main contact 202 When the movable electrode 11 completely contacts the fixed main contact 102 (when the movable element reaches the closing position), the protrusion 11A of the movable electrode 11 fits into the groove 212, and the movable electrode 11 is positioned at the retracted position.

When the movable element moves from the closing position to the closing position, the movable main contact 202 separates from the fixed main contact 102 and then the movable arc contact 202 moves to the fixed arc contact 101.
, and an arc A is generated between both arc contacts as shown in the upper half of FIG. As the movable element moves toward the cutoff position, the insulating nozzle 2 is removed from inside the cylinder 203.
Gas is blown onto the arc A through 04, thereby cooling the arc and extinguishing it at the current zero point.

Just before the movable element reaches the cutoff position, the movable electrode 1
The rear end of 1 is a stopper 30 (second movable electrode driving means)
When the movable element reaches the cutoff position, the protrusion 11A of the movable electrode fits into the groove 211 and the movable electrode 11 is moved toward the fixed element side relative to the movable arc contact 201. Position to forward position.

Although preferred embodiments of the present invention have been described above,
Appropriate modifications can be made to each part of the present invention.

For example, in the above embodiment, the first movable electrode drive means and the second movable electrode drive means were provided on the fixed element side and the movable side main circuit conductor side, respectively, but as in the embodiment shown in FIG. The movable electrode 11 has a protrusion (
In the example of FIG. 1, if the flange portion 11a) is provided, the above-mentioned driving means can also be provided on the side of the movable element.

In the above embodiment, the tip of the shield that covers the fixed main contact is used as the fixed contact for firing when closing, but the tip of the fixed main contact can also be used as the fixed contact for firing when closing. .

In the present invention, the movable electrode may be provided in such a way that an arc is generated between the movable arc contactor and the fixed contact portion before an arc is generated between the movable arc contactor and the fixed arc contactor when the movable electrode is turned on. As shown in Fig. 5, the movable electrode is configured to maintain close proximity to the fixed contact part at a distance that allows firing, and pass through the side of the fixed contact part to contact the fixed main contact. Alternatively, the movable electrode may be configured to contact the fixed contact portion and then contact the fixed main contact (in case the movable electrode also serves as the movable main contact).

In the above embodiment, a buffer type arc extinguishing mechanism is employed, but any type of arc extinguishing mechanism may be used in the present invention.

[Effects of the Invention] As described above, according to the present invention, in addition to the fixed arc contact and the movable arc contact, the movable electrode for firing at the time of closing, the fixed contact portion for firing at the time of closing, and the breaking of the circuit breaker are provided. A driving means for displacing the movable electrode between a forward position and a backward position in accordance with the operation and closing operation is provided, and when the circuit breaker is closed, the movable electrode for firing at the time of closing is positioned in the forward position. An arc is generated between the electrode and the fixed contact, and by placing the movable electrode for firing at the time of closing in the retracted position, an arc is generated between the movable arc contact and the fixed arc contact. This has the advantage of extending the life of the contacts, especially the life of the arc contacts that interrupt the main circuit current, and extending the life of circuit breakers that are frequently opened and closed. be.

[Brief explanation of drawings]

1 to 7 show embodiments of the present invention,
FIG. 1 is a vertical sectional view showing the structure of the main part of the embodiment of the present invention with the upper half in the closed state and the lower half in the closed state;
The figure is a vertical cross-sectional view showing the state when the cutoff arc and the make arc occur, with the upper half in the cutoff state and the lower half in the cutoff state. Figure 3 shows the upper half in the cutoff state and the lower half in the cutoff state. FIG. 4 is a vertical sectional view showing the structure of the main part of another embodiment of the present invention as a state, with the upper half in the middle of being cut off,
A vertical cross-sectional view showing the state when the breaking arc and closing arc occur in the embodiment of FIG. 3 with the lower half in the middle of closing, and FIG. 5 shows the movable electrode in the embodiment of FIG. Figure 6 is a cross-sectional view of the main part showing the state of contact, Figure 6 is a cross-sectional view of the main part showing an example of a device to reduce wear on the tip of the movable electrode, and Figure 7 is the fixation in the example of Figure 6. FIG. 8 is a front view of the main part showing the vicinity of the end of the main contact, and a sectional view showing the structure of a conventional circuit breaker with the upper half in the closed state and the lower half in the closed state. DESCRIPTION OF SYMBOLS 1... Fixed element, 100... Fixed side main circuit conductor, 101... Fixed arc contact, 102... Fixed main contact, 2... Movable element, 201... Movable arc Contactor, 202... Movable main contactor, 3... Movable side main circuit conductor, 8... First movable electrode drive means, 9
. . . Fixed contact portion for firing at the time of closing, 10 . . . Second movable electrode driving means. (1 other person) -～-

Claims (3)

[Claims] (1) A fixed element having a fixed arc contact; a closing position where the movable arc contact is in contact with the fixed arc contact; and a fixed element having a movable arc contact; In a circuit breaker, the movable element is provided so as to be displaced between a retracted position and a cutoff position in which the movable element is separated from a contact by a predetermined insulating distance and is in an open state. a movable electrode for firing at the time of closing that is movable relative to the movable arc contactor between an advanced position closer to the fixed element side than the fixed element, and the fixed element contacts the movable electrode at the time of closing. or at least a fixed contact portion for firing at the time of closing, which is brought close to a distance that allows firing, and in the process of the movable element being displaced toward the closing position, the movable arc contactor acts on the movable electrode to cause the movable arc contact to contact the fixed arc contactor. a first movable electrode driving means for displacing the movable electrode to the retracted position after contacting the movable element; and a second movable electrode driving means for displacing the movable electrode to the forward position after separating from the contact, and in the process of displacing the movable element toward the closing position while the movable electrode is at the forward position. Before the distance between the movable arc contactor and the fixed arc contactor reaches a distance that allows arcing, the distance between the movable electrode and the fixed contact section for arcing at the time of closing becomes a distance that allows arcing. The forward position is set so that the movable electrode is in the retracted position, and in the process of the movable element being displaced to the cutoff position side, the movable arc contactor contacts the movable electrode before it separates from the fixed arc contactor. A circuit breaker characterized in that the retracted position is set such that the distance between the fixed contact portion for firing at the time of closing becomes a distance that does not allow firing. (2) The fixed element and the movable element each further include a fixed main contact and a movable main contact, and in the breaking process, after the movable main contact is separated from the fixed main contact, the movable arc contact 2. The circuit breaker according to claim 1, wherein the positional relationship of the contacts is set such that the contacts are separated from the fixed main contact, wherein a shield is provided to cover the fixed main contact, and the tip of the shield is The circuit breaker is characterized in that the movable electrode also serves as a contact part of the movable main contact, and the movable electrode serves as the contact part for firing at the time of closing. (3) The tip of the fixed arc contactor is the fixed contact part for firing at the time of closing, and the movable electrode is provided concentrically with the movable arc contactor. 1. The circuit breaker according to 1.