JP2006236785A - Tripping apparatus of circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make other sound branch circuits continue normal feeding, since a host breaker does not open its contact until a subordinate breaker breaks an excess current, and only the subordinate breaker directly relating to an accident occurrence spot opens its contact to break an accidental current, by materializing a selective breaking action with a simple structure. <P>SOLUTION: The tripping apparatus TA of the host breaker is equipped with a movable iron piece 3 tripped by being displaced by magnetic attraction force due to the excess current, and a reset spring (b)6 giving deterrent force in accordance with the displacement of the movable iron piece 3 and stopping the movable iron piece 3 at a prescribed position in the first half cycle of the excess current to prevent it from being tripped, and when the excess current also continues in the next half cycle, the tripping apparatus is tripped by being displaced from the prescribed position where the movable iron piece 3 is deterred by the reset spring (b)6 by the magnetic attraction force due to the excess current. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates directly to an accident circuit in a circuit breaker trip device, particularly in a network having a main circuit breaker connected to the power supply side and a plurality of branch circuit breakers connected to the load side thereof. The present invention relates to a tripping device for a main circuit breaker used in a selective breaking system in which only a branch circuit breaker operates and other healthy circuits continue to supply power.

The circuit to be protected to which the circuit breaker tripping device of the prior art is applied is configured as shown in FIG. 1 as in the embodiment of the present invention.
In FIG. 1, a main circuit breaker (breaker B1) having a relatively large capacity is connected to the power source side, and a plurality of branch circuit breakers (breakers B2, B3) are connected in parallel to the load side of the main circuit breaker. Has been. These circuit breakers are provided to protect the load and wiring from overcurrent and short-circuit current. When overcurrent flows, the tripping device built in the circuit breaker trips and the circuit breaker contact opens. And the current is cut off to protect the load and wiring.
Taking FIG. 1 as an example, when an accident occurs at a point on the load side S1 of the breaker B1, the trip device of the breaker B1 trips and the accident current is interrupted. However, at the same time, power supply to the breakers B2 and B3 on the load side of the breaker 1 is also stopped.
As another example, a case where an accident occurs at a point on the load side S2 of the breaker B2 is given. In this case, the fault current flows in the breakers B1 and B2, and when the breaker B1 trips, power supply to the breaker B3, which is a sound circuit, is also stopped.
As described above, in general, when an accident occurs, the power supply to other healthy circuits is stopped. However, it is necessary to continue the power supply to the soundest circuit as much as possible.

Therefore, as a countermeasure against an accident that occurs in the branch circuit, a selective interruption method is employed, which is a protection method in which only a breaker directly related to the accident operates and other healthy circuits continue to supply power. In this method, it is necessary to consider the operating characteristic curves of both the main circuit breaker and the branch circuit breaker. If an accident occurs at the connection point of the lower circuit breaker, the time during which the breaker interrupts the accident current Only the opening action of the upper circuit breaker must be delayed. For example, if the operating characteristic curves of both circuit breakers are as shown in FIG. 2, it can be said that selective interruption is possible in the entire region of overcurrent because the characteristics of both do not intersect.
The opening operation of the upper circuit breaker is performed by a tripping device incorporated in the circuit breaker, and in order to realize the above-mentioned characteristics, the tripping device is not operated only while the lower circuit breaker interrupts the overcurrent. You can do that.
As for the selective blocking method, several techniques have been used so far, and the mechanical tripping delay method described below is one of them.

In the prior art, a tripping device for a circuit breaker capable of realizing a selective breaking system by a link mechanism has been proposed (see, for example, Patent Document 1).
In Patent Document 1, when the current flowing through the circuit exceeds a threshold value, the movable core 19 accumulates the operating spring 23 and displaces the operating member (inertia roller 21) via the engaging means (the operating pin 22). It is sucked halfway. However, since the displacement of the operating member (inertia roller 21) is blocked by the stopper means (inertia roller holding arm 20a), the movable core 19 is engaged with the trip shaft operating arm 14a that is released from the latch of the trip latch 15. It is not sucked to the position where In this state, when the current is decreased and the attractive force of the movable core 19 and the fixed core 18 is weakened, the stored operating spring 23 is released and the operating member ( The inertia roller 21) is displaced.
In this way, the value of the current exceeds the threshold value again until the movable member 19 is displaced by the action of the return spring 24 until the movement member (inertia roller 21) displaced by the release of the movement spring 23 returns to the original position. When re-suctioned, the movable core 19 does not engage with the engaging means (operating pin 22), so that the movable core 19 is sufficiently moved without being affected by the stopper means (inertia roller holding arm 20a), and the tripshaft operating arm. 14a is engaged and the latch of the trip latch 15 is released to open the open circuit breaker.
In an electric circuit using a circuit breaker using this technique, even if a current exceeding the operation threshold of the tripping device flows once, the circuit breaker is not opened.

Japanese Patent Laid-Open No. 10-229589

  In the configuration shown in Patent Document 1, the tripping device that enables such a selective blocking method has a complicated configuration that includes a large number of parts and includes a link mechanism.

  The present invention has been made to solve the above-described problems. By realizing a selective breaking operation with a simple configuration, the upper breaker is operated until the lower breaker cuts off the overcurrent. Therefore, only the lower circuit breaker that is directly related to the location of the accident will open and shut off the accident current so that other healthy branch circuits can continue normal power supply. To do.

  In the circuit breaker tripping device according to the present invention, the upper circuit breaker and the lower circuit breaker are connected to the upper circuit breaker connected to the power supply side and the plurality of lower circuit breakers connected to the upper circuit breaker. In a tripping device for a circuit breaker that performs selective breaking with a circuit breaker, the tripping device for the upper circuit breaker includes an actuating member made of a magnetic material that performs a tripping operation by being displaced by a magnetic attraction force due to overcurrent. A depressing means for applying a deterring force to the actuating member according to the displacement of the actuating member, deterring the actuating member to a predetermined position in the first half cycle of an overcurrent, and preventing a tripping operation by the actuating member. When the overcurrent continues in the next half cycle, the actuating member is displaced from the predetermined position inhibited by the inhibiting means by the magnetic attraction force caused by the overcurrent so as to perform the tripping operation. One in which the.

  According to the present invention, by realizing the selective breaking operation with a simple configuration, the upper breaker does not reach the opening operation until the lower breaker cuts off the overcurrent, and directly to the location where the accident occurred. Only the relevant lower circuit breaker opens and shuts off the fault current, and other healthy branch circuits can continue normal power feeding.

Embodiment 1 FIG.
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a connection diagram illustrating a circuit to be protected to which a tripping device for a circuit breaker according to Embodiment 1 is applied. FIG. 2 is an operation characteristic curve diagram of the upper circuit breaker and the lower circuit breaker that enables selective circuit breakage in the protection target circuit to which the circuit breaker tripping device according to the first embodiment is applied. FIG. 3 is a cross-sectional view showing a main part of the circuit breaker tripping device according to the first embodiment. FIG. 4 is a top view showing a main part of the circuit breaker tripping device according to the first embodiment. FIG. 5 is a perspective view of a return spring for biasing the movable iron piece in the first embodiment. FIG. 6 is a waveform diagram showing an overcurrent flowing through the tripping device according to the first embodiment.

In FIG. 1 showing a circuit to be protected to which the circuit breaker tripping device according to the first embodiment is applied, a main circuit breaker (breaker B1) having a relatively large capacity is connected to the power supply side, and this main circuit breaker is connected. A plurality of branch circuit breakers (breakers B2, B3) are connected in parallel to the load side. These circuit breakers are provided to protect the load and wiring from overcurrent and short-circuit current. When overcurrent flows, the tripping device built in the circuit breaker trips and the circuit breaker contact opens. And the current is cut off to protect the load and wiring.
When an accident occurs at a point on the load side S1 of the breaker B1, the trip device of the breaker B1 trips and the accident current is interrupted.
In addition, when an accident occurs at a point on the load side S2 of the breaker B2, the fault current flows in the breakers B1 and B2, and the breaker B1 trips to the breaker B3, which is a healthy circuit. In order to prevent the power feeding of the breaker B from being stopped, the selective cutoff operation is performed so that the breaker B2 trips before the trip operation of the breaker B1.
As a countermeasure against an accident that occurs in a branch circuit, a selective cutoff method is employed, which is a protection method in which only a breaker directly related to the accident operates and other healthy circuits continue to supply power.

As shown in FIG. 2, the operating characteristic of the breaker B1 as the main circuit breaker is set as an operating characteristic curve M, and the operating characteristics of the breakers B2 and B3 as the branch circuit breaker are as shown in the operating characteristic curve N. It is set and the characteristics of the two do not intersect, so it can be said that selective blocking is possible in the entire region of overcurrent.
When an accident occurs at the connection point of breakers B2 and B3 as branch circuit breakers constituting the lower circuit breaker, the main circuit breaker constituting the upper circuit breaker only during the time when the breaker interrupts the accident current As a result, the opening operation of the breaker B1 can be delayed.
The opening operation of the upper circuit breaker is performed by the tripping device TA incorporated in the circuit breaker. In order to realize the above-described characteristics, the tripping device TA is used only while the lower circuit breaker interrupts the overcurrent. Do not let it work.

  In FIG. 3 and FIG. 4 showing the configuration of the circuit breaker tripping device TA composed of the breaker B1 constituting the main circuit breaker as the upper circuit breaker in the first embodiment, the circuit breaker tripping device TA is a circuit breaker housing. It is housed in the body and integrated with the circuit breaker body. When an overcurrent flows through the circuit breaker itself due to an accident or the like, the tripping device TA operates to perform the tripping operation of the trip bar 7 with respect to the latch 10 and opens the circuit breaker contact via a link mechanism not shown in the figure. It has an extreme structure.

3 and 4, the electric circuit 1 is mechanically connected to a circuit breaker contact (not shown), and the frame 2 of the tripping device TA for opening the circuit breaker contact is attached to face the electric circuit 1. It has been. A movable iron piece 3 made of a magnetic material is incorporated in the frame 2 so as to be rotatable about a shaft 4, and a return spring (a) 5 and a return spring (b) for imparting a resistance force to the movable iron piece 3 in a clockwise direction. It consists of six.
The two return springs 5 and 6 shown here are springs having a double torsion bar structure as shown in FIG. FIG. 5A is a perspective view showing the external configuration of the return spring (a) 5. FIG. FIG. 5B is a perspective view showing the external configuration of the return spring (b) 6.
The return spring (a) 5 and the return spring (b) 6 may be any type of spring (plate spring, coil spring, etc.) as long as they can apply a drag force to the movable iron piece 3 in implementation.
Since the return spring (a) 5 always applies a drag force to the movable iron piece 3, the position shown in the figure is the fixed position of the movable iron piece when the circuit is healthy. The return spring (b) 6 has a structure in which the drag is additionally applied from the middle of the movable iron piece 3 rotating counterclockwise while resisting the drag of the return spring (a) 5.
A movable trip bar 7 is provided at a position where the movable iron piece 3 has pushed the drag from the return spring (a) 5 and the return spring (b) 6 and rotated counterclockwise and reached. It consists of an operating arm 8 that the movable iron piece 3 contacts and a latch holder 9 that holds the latch 10. Although not shown in the drawing, the latch 10 is linked to a circuit breaker contact opening mechanism, and when the latch holder 9 is released, the circuit breaker contact opens.

With such a configuration, when an overcurrent having a waveform as shown in FIG. 6 flows in the electric circuit 1 due to a short circuit accident or the like, the magnetic flux of the electric circuit 1 facing the movable iron piece 3 flows in the magnetic circuit of the movable iron piece 3 and the magnetic attractive force Will occur.
6, as the current value increases toward the peak P1, the magnetic attraction force gradually increases, and the movable iron piece 3 increases the distance from the trip bar 7 against the drag from the return spring (a) 5. In the counterclockwise direction of shrinking, rotational displacement starts about the axis 4. At the start of displacement, the magnetic attractive force acting on the movable iron piece 3 increases as the current value increases and the distance from the electric circuit 1 approaches, but in the middle it collides with the return spring (b) 6 and the drag is renewed. In addition, since the magnetic attraction force is weakened when the overcurrent enters the region R2 and reaches the current zero point, the movable iron piece 3 temporarily stops at that position or tries to move backward in the clockwise direction.
Thereafter, when the current enters the region R3 and increases again toward the peak P2, since the movable iron piece 3 is located closer to the electric circuit 1 than the initial position, the generated magnetic attraction force is greater than the overcurrent region R1. It is greatly generated, and the drag of the return spring (a) 5 and the return spring (b) 6 can be sufficiently pushed, and the trip bar 7 is caused to generate a clockwise rotational force in contact with the operating arm 8. As a result, the trip bar 7 rotates to disengage the latch holder 9 from the latch 10, and the link mechanism that transmits the opening operation of the circuit breaker contact not shown in the figure starts to operate. Leads to opening.

Therefore, the breaker B1 constituting the main circuit breaker as the upper circuit breaker in which the tripping device TA is incorporated does not reach the opening operation in the first 0.5 cycle of the overcurrent.
On the other hand, the breaker B2, B3 constituting the branch circuit breaker as the lower circuit breaker does not employ the configuration of the tripping device TA including the return spring (b) 6 and the like, and the breakers B2, B3 Is configured to accurately perform the opening operation in the first 0.5 cycle of the overcurrent, so only the breaker B2 as the lower circuit breaker directly related to the location of the accident is opened and the accident current is generated. Other branch circuits that are cut off and healthy can continue normal power feeding. Breaker B1 continues to supply power without performing an opening operation in the first 0.5 cycle, and breaker B3 maintains a closed state without causing an accident current, and the breaker B3 is connected to a healthy state. The branch circuit is kept in a normal state and continues to supply power to the load.

  According to Embodiment 1 of the present invention, a high-order circuit breaker comprising a breaker B1 as a main circuit breaker connected to the power supply side and a high-order circuit breaker comprising a breaker B1 serving as the main circuit breaker are branched in parallel. A plurality of lower circuit breakers composed of breakers B2 and B3 as branch circuit breakers connected to the load circuit, and a higher circuit breaker composed of breaker B1 serving as the main circuit breaker and the branch circuit breaker In the circuit breaker tripping device for selectively cutting off the lower circuit breaker consisting of the breakers B2 and B3 as described above, the tripping device TA of the upper circuit breaker consisting of the breaker B1 is displaced by the magnetic attractive force due to overcurrent. An actuating member composed of a movable iron piece 3 made of a magnetic material that performs a tripping operation, and an actuating member composed of the movable iron piece 3 Depending on the position, the actuating member composed of the movable iron piece 3 is given a deterring force, and the actuating member composed of the movable iron piece 3 is restrained to a predetermined position in the first half cycle of overcurrent, and the movable iron piece 3 is constituted. A depressing means for preventing the tripping action by the actuating member, and when the overcurrent continues in the next half cycle, the magnetic attracting force due to the overcurrent from the predetermined position where the actuating member is deterred by the inhibiting means The tripping device TA of the upper circuit breaker composed of the breaker B1 is moved in the direction opposite to the tripping operation with respect to the operating member composed of the movable iron piece 3. When the operating member composed of the first return spring (a) 5 and the movable iron piece 3 is displaced, additional drag is applied to the operating member composed of the movable iron piece 3 from the middle. Since the second return spring (b) 6 as the restraining means is provided, a second return spring is provided to add a drag force to the operating member when the operating member is displaced. By realizing the selective circuit breaker operation, the upper circuit breaker does not reach the opening operation until the lower circuit breaker cuts off the overcurrent, and only the lower circuit breaker directly related to the accident location opens the circuit. Thus, the fault current is interrupted, and other healthy branch circuits can continue normal power feeding.

Embodiment 2. FIG.
A second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a cross-sectional view showing a main part of the circuit breaker tripping device according to the second embodiment. FIG. 8 is a top view showing a main part of the circuit breaker tripping device according to the second embodiment.
In the second embodiment, the configuration other than the specific configuration described here has the same configuration contents as the configuration in the first embodiment described above, and exhibits the same operation. In the drawings, the same reference numerals indicate the same or corresponding parts.

  In FIG. 7 and FIG. 8 showing the configuration of the circuit breaker tripping device TA composed of the breaker B1 (see FIG. 1) constituting the main circuit breaker as the upper circuit breaker in the second embodiment, the circuit breaker tripping device is shown. TA is accommodated in the circuit breaker housing and integrated with the circuit breaker body. When an overcurrent flows through the circuit breaker itself due to an accident or the like, the tripping device TA operates to perform the tripping operation of the trip bar 7 with respect to the latch 10 and opens the circuit breaker contact via a link mechanism not shown in the figure. It has an extreme structure.

7 and 8, the electric circuit 1 is mechanically connected to the circuit breaker contact, and the frame 2 of the circuit breaker contact tripping device is attached to face the electric circuit 1. A movable iron piece 3 made of a magnetic material is incorporated in the frame 2 so as to be rotatable about a shaft 4, and further includes a return spring 5 that applies a drag force to the movable iron piece 3 in the clockwise direction.
The return spring 5 shown here is a spring having a double torsion bar structure as shown in FIG. The return spring 5 can be of any kind (such as a leaf spring or a coil spring) as long as it can provide a drag force to the movable iron piece 3 during implementation.
Since the return spring 5 always applies a drag force to the movable iron piece 3, the position in the figure is the fixed position of the movable iron piece 3 in a state where the circuit is healthy. Further, an air dash pot 11 is attached to the movable iron piece 3 so that a drag force is applied when the movable iron piece 3 is rotationally displaced counterclockwise.
A movable trip bar 7 is provided at a position where the movable iron piece 3 pushes the drag from the return spring 5 and rotates counterclockwise and arrives. The trip bar 7 is connected to the operating arm 8 with which the movable iron piece 3 contacts. The latch holder 9 holds the latch 10. Although not shown in the drawing, the latch 10 is linked to a circuit breaker contact opening mechanism, and when the latch holder 9 is released, the circuit breaker contact opens.

With such a configuration, when an overcurrent as shown in FIG. 6 flows in the electric circuit 1 due to a short circuit accident or the like, the magnetic flux of the electric circuit 1 facing the movable iron piece 3 flows into the magnetic circuit of the movable iron piece 3 to generate a magnetic attractive force. To do.
6, as the current value increases toward the peak P <b> 1, the magnetic attractive force gradually increases, and the movable iron piece 3 counteracts the drag from the return spring 5 to reduce the distance from the trip bar 7. In the direction, it starts to be rotationally displaced about the axis 4. At the beginning of the displacement, the magnetic attractive force acting on the movable iron piece 3 increases as the current value increases and the distance from the electric circuit 1 approaches, but the drag from the air dashpot 11 increases along the way, Further, since the magnetic attraction force is weakened when the overcurrent enters the region R2 and approaches the current zero point, the movable iron piece 3 once stagnates or retreats in the clockwise direction at that position.
Thereafter, when the current enters the region R3 and increases again toward the peak P2, since the movable iron piece 3 is located closer to the electric circuit 1 than the initial position, the generated magnetic attraction force is greater than the overcurrent region R1. A large amount is generated, and the drag of the return spring 5 and the air dash pot 11 can be sufficiently pushed, and the trip bar 7 is caused to generate a clockwise rotational force by contacting the operating arm 8. As a result, the trip bar 7 rotates to disengage the latch holder 9 from the latch 10, and the link mechanism that transmits the opening operation of the circuit breaker contact not shown in the figure starts to operate. Leads to opening.

Therefore, the breaker B1 (see FIG. 1) constituting the main circuit breaker as the upper circuit breaker in which the tripping device TA is incorporated does not reach the opening operation in the first 0.5 cycle of the overcurrent.
On the other hand, the breaker B2, B3 (see FIG. 1) constituting the branch circuit breaker as the lower circuit breaker does not employ the configuration of the trip device TA including the air dash pot 11 and the like. Since B2 and B3 are configured to accurately perform the opening operation in the first 0.5 cycle of the overcurrent, only the breaker B2 as a lower circuit breaker that is directly related to the location of the accident is opened. The fault current is cut off, and other healthy branch circuits can continue normal power supply. Breaker B1 continues to supply power without performing an opening operation in the first 0.5 cycle, and breaker B3 maintains a closed state without causing an accident current, and the breaker B3 is connected to a healthy state. The branch circuit is kept in a normal state and continues to supply power to the load.

  According to Embodiment 2 of the present invention, an upper circuit breaker comprising a breaker B1 (see FIG. 1) as a main circuit breaker connected to the power supply side, and an upper circuit breaker comprising a breaker B1 as the main circuit breaker. A plurality of lower circuit breakers consisting of breakers B2 and B3 (see FIG. 1) as branch circuit breakers connected in parallel and connected to the load circuit from the breaker B1 as the main circuit breaker In the tripping device for the circuit breaker for selectively cutting off the upper circuit breaker and the lower circuit breaker comprising the breakers B2 and B3 as the branch circuit breaker, the tripping device TA for the upper circuit breaker comprising the breaker B1 Is an actuating member composed of a movable iron piece 3 made of a magnetic material that is displaced by a magnetic attraction force due to an overcurrent and performs a tripping operation, and the movable iron piece A depressing force is applied to the actuating member constituted by the movable iron piece 3 in accordance with the displacement of the actuating member constituted by, and the actuating member constituted by the movable iron piece 3 is inhibited at a predetermined position in the first half cycle of overcurrent. And a deterring means for preventing the tripping operation by the actuating member constituted by the movable iron piece 3, and when the overcurrent continues in the next half cycle, the actuating member is deterred by the inhibiting means at a predetermined position. The tripping device TA is displaced by a magnetic attraction force due to overcurrent to perform a tripping operation, and the tripping device TA of the upper circuit breaker composed of the breaker B1 is provided with respect to the operating member composed of the movable iron piece 3 When the operating member is displaced in the tripping operation direction, a drag is applied to the actuating member formed of the movable iron piece 3 when the actuating member is displaced in the tripping operation direction. Since the air dash pot 11 is provided as a deterrent means, by providing an air dash pot that applies a drag force to the operating member when the operating member is displaced, and realizing a selective blocking operation with a simple configuration, the upper circuit breaker is Until the lower circuit breaker cuts off the overcurrent, the opening operation will not occur. Only the lower circuit breaker directly related to the location of the accident will open the circuit and cut off the accident current. The circuit can continue normal power feeding.

Embodiment 3 FIG.
A third embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a cross-sectional view showing a main part of the circuit breaker tripping device according to the third embodiment. FIG. 10 is a top view showing a main part of a tripping device for a circuit breaker according to the third embodiment.
In the third embodiment, the configuration other than the specific configuration described here has the same configuration contents as the configuration in the first embodiment described above, and has the same function. In the drawings, the same reference numerals indicate the same or corresponding parts.

  In FIG. 9 and FIG. 10 showing the configuration of the circuit breaker tripping device TA composed of the breaker B1 (see FIG. 1) constituting the main circuit breaker as the upper circuit breaker in Embodiment 3, the circuit breaker tripping device is shown. TA is accommodated in the circuit breaker housing and integrated with the circuit breaker body. When an overcurrent flows through the circuit breaker itself due to an accident or the like, the tripping device TA operates to perform the tripping operation of the trip bar 7 with respect to the latch 10 and opens the circuit breaker contact via a link mechanism not shown in the figure. It has an extreme structure.

9 and 10, the electric circuit 1 is mechanically connected to the circuit breaker contact, and the frame 2 of the circuit breaker contact tripping device is attached to face the electric circuit 1. A movable iron piece 3 made of a magnetic material is incorporated in the frame 2 so as to be rotatable about a shaft 4, and further includes a return spring 5 that applies a drag force to the movable iron piece 3 in the clockwise direction.
The return spring 5 shown here is a spring having a double torsion bar structure as shown in FIG. The return spring 5 can be of any kind (such as a leaf spring or a coil spring) as long as it can provide a drag force to the movable iron piece 3 during implementation.
Since the return spring 5 always applies a drag force to the movable iron piece 3, the position in the figure is the fixed position of the movable iron piece when the circuit is healthy. Further, a brake plate 13 made of resin or the like is attached to the frame side plate 12, and when the movable iron piece 3 is rotationally displaced counterclockwise, the brake plate 13 is brought into contact with the brake plate 13 to increase the drag force.
A movable trip bar 7 is provided at a position where the movable iron piece 3 pushes the drag from the return spring 5 and rotates counterclockwise, and the trip bar 7 is latched with the operating arm 8 which the movable iron piece contacts. It consists of a latch holder 9 for holding 10. Although not shown in the drawing, the latch 10 is linked to a circuit breaker contact opening mechanism, and when the latch holder 9 is released, the circuit breaker contact opens.

With such a configuration, when an overcurrent as shown in FIG. 6 flows in the electric circuit 1 due to a short circuit accident or the like, the magnetic flux of the electric circuit 1 facing the movable iron piece 3 flows into the magnetic circuit of the movable iron piece 3 to generate a magnetic attractive force. To do.
6, as the current value increases toward the peak P <b> 1, the magnetic attractive force gradually increases, and the movable iron piece 3 counteracts the drag from the return spring 5 to reduce the distance from the trip bar 7. In the direction, it starts to be rotationally displaced about the axis 4. At the beginning of the displacement, the magnetic attractive force acting on the movable iron piece 3 increases as the current value increases and the distance from the electric circuit 1 approaches, but a drag force from the brake plate 13 is newly added in the middle of the displacement, Further, since the magnetic attraction force is weakened when the overcurrent enters the region R2 and approaches the current zero point, the movable iron piece 3 once stagnates or retreats in the clockwise direction at that position.
After that, when the current enters the region R3 and increases again toward the peak P2, the movable iron piece 3 is located closer to the electric circuit 1 than the initial position, so that the generated magnetic attraction force is greater than the overcurrent region P1. A large amount is generated, and the drag force of the return spring 5 and the brake plate 13 can be sufficiently pushed, and the trip bar 7 is caused to rotate in the clockwise direction by contacting the operating arm 8. As a result, the trip bar 7 rotates to disengage the latch holder 9 from the latch 10, and the link mechanism that transmits the opening operation of the circuit breaker contact not shown in the figure starts to operate. Leads to opening.

Therefore, the breaker B1 (see FIG. 1) constituting the main circuit breaker as the upper circuit breaker in which the tripping device TA is incorporated does not reach the opening operation in the first 0.5 cycle of the overcurrent.
On the other hand, the breaker B2, B3 (see FIG. 1) constituting the branch circuit breaker as the lower circuit breaker does not employ the configuration of the trip device TA including the brake plate 13 and the like, and the breaker B2 , B3 is configured to accurately perform the opening operation in the first 0.5 cycle of the overcurrent, so only the breaker B2 as the lower circuit breaker directly related to the location of the accident opens the operation. The current is cut off, and another healthy branch circuit can continue normal power supply. Breaker B1 continues to supply power without performing an opening operation in the first 0.5 cycle, and breaker B3 maintains a closed state without causing an accident current, and the breaker B3 is connected to a healthy state. The branch circuit is kept in a normal state and continues to supply power to the load.

  According to Embodiment 3 of the present invention, an upper circuit breaker comprising a breaker B1 (see FIG. 1) as a main circuit breaker connected to the power supply side, and an upper circuit breaker comprising a breaker B1 as the main circuit breaker. A plurality of lower circuit breakers consisting of breakers B2 and B3 (see FIG. 1) as branch circuit breakers connected in parallel and connected to the load circuit from the breaker B1 as the main circuit breaker In the tripping device for the circuit breaker for selectively cutting off the upper circuit breaker and the lower circuit breaker comprising the breakers B2 and B3 as the branch circuit breaker, the tripping device TA for the upper circuit breaker comprising the breaker B1 Is an actuating member composed of a movable iron piece 3 made of a magnetic material that is displaced by a magnetic attraction force due to an overcurrent and performs a tripping operation; A depressing force is applied to the actuating member constituted by the movable iron piece 3 in accordance with the displacement of the actuating member constituted by, and the actuating member constituted by the movable iron piece 3 is inhibited at a predetermined position in the first half cycle of overcurrent. And a deterring means for preventing the tripping operation by the actuating member constituted by the movable iron piece 3, and when the overcurrent continues in the next half cycle, the actuating member is deterred by the inhibiting means at a predetermined position. The tripping device TA is displaced by a magnetic attraction force due to overcurrent to perform a tripping operation, and the tripping device TA of the upper circuit breaker composed of the breaker B1 is provided with respect to the operating member composed of the movable iron piece 3 When the actuating member composed of the return spring 5 and the movable iron piece 3 that imparts a drag force in the direction opposite to the tripping operation is displaced in the tripping operation direction, the movable spring piece 3 is configured. Since the brake member made of the brake plate 13 made of resin or the like as the restraining means that slides and contacts the member from the middle is provided, when the operating member is displaced, the drag is applied to the working member from the middle. By providing a brake member and realizing a selective breaking operation with a simple configuration, the upper breaker does not reach the opening operation until the lower breaker shuts off the overcurrent, and directly to the location where the accident occurred. Only the relevant lower circuit breaker opens and shuts off the fault current, and other healthy branch circuits can continue normal power feeding.

BRIEF DESCRIPTION OF THE DRAWINGS It is a connection diagram which shows the protection object circuit to which the trip device of the circuit breaker in Embodiment 1 by this invention is applied. FIG. 2 is a circuit diagram showing a general circuit breaker connection in the background art in a protection target circuit to which the circuit breaker tripping device according to the first embodiment is applied. It is an operation characteristic curve figure of a high-order circuit breaker and a low-order circuit breaker which enables selective interception in a protection object circuit to which a tripping device of a circuit breaker in Embodiment 1 by this invention is applied. It is sectional drawing which shows the principal part of the trip device of the circuit breaker in Embodiment 1 by this invention. It is a top view which shows the principal part of the trip device of the circuit breaker in Embodiment 1 by this invention. It is a perspective view of the return spring which urges the movable iron piece in Embodiment 1, Embodiment 2 and Embodiment 3 by this invention. It is a wave form diagram which shows the overcurrent which flows into the tripping device in Embodiment 1 and Embodiment 2 and Embodiment 3 by this invention. It is sectional drawing which shows the principal part of the trip device of the circuit breaker in Embodiment 2 by this invention. It is a top view which shows the principal part of the trip device of the circuit breaker in Embodiment 2 by this invention. It is sectional drawing which shows the principal part of the trip device of the circuit breaker in Embodiment 3 by this invention. It is a top view which shows the principal part of the trip device of the circuit breaker in Embodiment 3 by this invention.

Explanation of symbols

1 Electric circuit, 2 frames, 3 movable iron pieces, 4 shafts, 5 return spring (a), 6 return spring (b), 7 trip bar, 8 movable arm, 9 latch holder, 10 latch, 11 air dash pot, 12 frame side plate , 13 Brake plate.

Claims (4)

  A circuit breaker for selectively cutting off the upper breaker and the lower breaker for a higher breaker connected to the power supply side and a plurality of lower breakers connected to the upper breaker. In the tripping device, the tripping device of the upper circuit breaker includes an actuating member made of a magnetic material that performs a tripping operation by being displaced by a magnetic attraction force due to an overcurrent, and an actuating member that moves according to the displacement of the actuating member. When the overcurrent continues in the next half cycle, the depressing force is applied and the actuating member is restrained to a predetermined position in the first half cycle of the overcurrent and the tripping operation by the actuating member is prevented. The circuit breaker tripping device is characterized in that a tripping operation is performed by displacing the operating member from a predetermined position restrained by the restraining means by a magnetic attractive force due to overcurrent. .   The tripping device for the upper circuit breaker adds a first return spring for applying a drag force in the opposite direction to the tripping operation to the actuating member, and a drag force is added to the actuating member halfway when the actuating member is displaced. The circuit breaker tripping device according to claim 1, further comprising a second return spring as the restraining means to be applied.   The tripping device for the upper circuit breaker has a return spring that applies a drag force in the direction opposite to the tripping operation to the operating member, and a drag force applied to the operating member when the operating member is displaced in the tripping operation direction. 2. The circuit breaker tripping device according to claim 1, further comprising an air dash pot as the restraining means. The tripping device for the upper circuit breaker includes a return spring for applying a drag force in the direction opposite to the tripping operation to the actuating member, and a drag force on the actuating member when the actuating member is displaced in the tripping operation direction. The circuit breaker tripping device according to claim 1, further comprising a brake member serving as the restraining means for imparting a resistance.

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