JPH088052B2 - Circuit breaker - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a circuit breaker.

[Background technology]

An abnormal current, for example, when a short circuit occurs, a conventional example (Japanese Patent Laid-Open No. 57-196440) for extinguishing the arc by inserting a shield plate for extinguishing the arc between the movable contact and the fixed contact is disclosed.
As shown in the figure, there were the following drawbacks. That is, since the shield plate 101 moves between the fixed contact 102 and the movable contact 103 in conjunction with the opening / closing operation of the movable contact 100 by the operation of the link mechanism portion of the opening / closing / tripping means 104, it is possible to move from the occurrence of a short circuit. Open / close / trip means 1 until contact 103 begins to open 1
Since the delay time due to the operation of the link mechanism part of 04 is about 2 to 4 ms, and the moving contact 103 is about 3 to 6 ms from the start of the opening to the completion of the opening, the shield plate 101 from the occurrence of the short circuit.
Requires about 5-10ms to complete the operation. In Fig. 6, the spring force of the opening spring is set to a large value so that the shield plate 101 has about 5
The arc waveform when the operation is completed in ms is shown. Q ₁ is the contact arc voltage, Q ₂ is the breaking current, and Q ₃ is the estimated short-circuit current.

Thus, even if the spring force of the opening spring is set to a large value and the shield plate 101 is operated, the peak value of the short-circuit current is reached due to the delay of about 5 ms. The peripheral molded product and the shielding plate 101 are largely damaged. If the spring force of the opening spring is increased,
Since the load of operating the handle becomes large, it becomes an operation burden.

As a result, there is a drawback in that it is not possible to shorten the time until the operation of the shield plate 101 is completed and it is not possible to obtain a large blocking capacity.

[Object of the Invention]

An object of the present invention is to provide a circuit breaker capable of increasing the breaking capacity by shortening the time from the occurrence of a short circuit to the completion of the operation of the shield plate without increasing the operating load of the handle. .

[Disclosure of Invention]

A circuit breaker according to the present invention includes a fixed contact having a fixed contact, a movable contact having a movable contact facing the fixed contact so that the movable contact can be separated from the fixed contact, and the movable contact has a contact opening operation. An arc extinguishing shield plate that enters between the movable contact and the fixed contact, and an electromagnet that detects the abnormal current of the load and forcibly opens the movable contact at the movable portion when the abnormal current is detected, The movable part is provided with an opening / closing means for trip-opening the movable contact that is forcibly opened in association with a detection part that detects an abnormal current of the load while opening and closing the movable contact with a handle. The forced opening distance for directly opening the movable contact by directly acting on the movable contact is at least the distance at which the shield plate can enter between the movable contact and the fixed contact.

According to the configuration of the present invention, when an abnormal current, for example, a short-circuit current flows, the movable contact is forcibly opened by the movable portion of the electromagnet before the opening / closing / trip means trips.
The shield plate enters between the fixed contact and the movable contact without interlocking with the opening operation of the movable contactor by the operation of the opening / closing / tripping means. As a result, there is no influence of the delay time due to the operation of the opening / closing / tripping means, so the time from the occurrence of an abnormal current to the completion of the operation of the shield plate can be shortened, and the arc interruption time can be short-circuited, resulting in a large interruption capacity. can do. Moreover, since it is not necessary to increase the spring force of the opening spring of the opening / closing / tripping means, the operating load of the handle is not increased.

Embodiments A first embodiment of the present invention will be described with reference to FIGS. 1 to 7. That is, this circuit breaker comprises a fixed contactor 2 having a fixed contact 1, a movable contactor 4 having a movable contact 3 facing the fixed contact 1 so as to be able to come into contact with and separated from the fixed contact 1, and an opening of the movable contactor 4. An arc-extinguishing shield 9 that enters between the movable contact 3 and the fixed contact 1 in conjunction with the operation, and an abnormal current of the load is detected. The electromagnet 5 forcibly opening the contactor 4 and the movable contactor 4 forcibly opened are tripped in conjunction with a detection unit for opening / closing the movable contactor 4 with a handle 6 and detecting an abnormal current of a load. The opening / closing / tripping means 8 for opening the contact is provided, and the movable portion 7 directly acts on the movable contactor 4 to force the contact to open, and at least the shield plate 9 is provided between the movable contact 3 and the fixed contact 1. It is set as a distance that can enter.

In FIG. 1, reference numeral 10 has an opening (not shown) for assembling parts on the side surface (direction perpendicular to the paper surface of FIG. 1) and 1
When the circuit breaker has a plurality of poles and constitutes a circuit breaker having a plurality of poles, the cases 10 are arranged in parallel and are connected by passing caulking pins (not shown) through the connection holes 13. 11 is a load side terminal provided at one end of the case 10,
Reference numeral 12 is a power supply side terminal provided at the other end of the case 10, and 14 is a case mounting groove.

The opening / closing / trip means 8 includes a handle 6, a frame 15, an operation link 19, an operating shaft 20, a movable frame 30, a latch link 23, a trip link 24, and an opening spring 42.
It is composed of the electromagnet 5 and the detection unit as an example. The frame 15 is held in the case 10. The handle 6 is rotatably provided on the upper end of the frame 15 in FIG.
A part thereof is exposed and a reset protrusion 68 is formed inside the case 10. A movable shaft 18 is provided at an inner end portion of the handle 6, one end of an operation link 19 is connected to the movable shaft 18, and an operation shaft 20 is connected to the other end. In addition, the movable shaft 18 and the frame 15
A handle return spring 22 having a pulling action is suspended between a spring receiver 21 provided at a lower position of the handle 6 and urges the handle 6 to the neutral position shown in FIG. The upper end of the latch link 23 is rotatably connected to the fixed shaft 16, and the operating shaft 20 slidably contacts one side surface of the lower end of the latch link 23. A trip link (24) is rotatably provided by a fixed shaft (25) on a frame (15) at a position opposite to the operating shaft (20) of the latch link (23).

The trip link 24 includes a latch portion 24a at the tip, a short-circuit response portion 27 at an intermediate portion, an overcurrent response portion 26 extending above the fixed shaft 25, and a return spring 28. The return spring 28 has a winding portion supported by the fixed shaft 25, one end of which is engaged with the overcurrent response portion 26, and the other end of which is engaged with the frame 15, so that the trip link 24
Is urged to rotate clockwise in FIG. 1, and is positioned by a stopper (not shown) provided on the frame 15 at the position shown in FIG. In this state, the latch portion 24a is in a latched state in which the lower end portion of the latch link 23 is abutted and locked, and the latch link 23 is regulated so as not to rotate counterclockwise around the fixed shaft 16.

A pair of guides 29 are provided on the side wall of the case 10 below the operation link 19, and a movable frame 30 is guided between the guides 29 so as to be slidable in the vertical direction in FIG. The movable frame 30 is formed with a bearing recess 31 (see FIG. 5) at the upper end thereof, and the bearing recess 31 can be engaged with the operating shaft 20 in a state of preventing the operating shaft 20 from moving downward.

The electromagnet 5 is of a plunger type, and has a movable part 7 as a plunger, a coil cylinder 33 having the movable part 7 therein, a yoke 40 extending over both ends of the coil cylinder 33, and a coil cylinder inside the yoke 40. A coil 32 wound around 33, a fixed iron core 41 facing the movable portion 7 in the coil cylinder 33, and a return spring (not shown) interposed between the movable portion 7 and the fixed iron core 41. . The yoke 40 is fixed to the frame 15 below the trip link 24. The movable portion 7 is integrally provided with a forced opening rod 7a that penetrates the fixed iron core 41, and has a brim-shaped engaging portion 34 at the upper end portion of the movable portion 7.
By the operation of the electromagnet 5 so as to engage with the short-circuit response portion 27 of the trip link 24. The movable part 7 is pushed upward by the return spring (not shown) in FIG.
The stepped portion is positioned by being locked to the inner stepped portion at the upper end of the coil tube 33. The return spring (not shown) can also be used as the return spring 28 of the trip link 24.

The electromagnet 5 detects a short-circuit current by setting the spring force of a return spring (not shown), but a bimetal 38 is provided in the case 10 to detect an overcurrent. bimetal
The base end of 38 is fixed to the load side terminal 11, a gap adjusting screw 39 is provided at the tip, and the tip of the gap adjusting screw 39 faces the overcurrent response portion 26.

The movable contactor 4 is supported in a state in which an intermediate portion thereof is biased upward by an opening spring 42, the movable contact 3 is fixed to a tip portion thereof, and a rear end portion 43a faces a forced opening rod 7a. Further, the tip of the rear end portion 43a is folded back in a U shape, and the curved portion 43 of the rear end portion 43a faces the lower surface of the yoke 40 which is the lower end of the electromagnet 5, and further the opening spring 42 and the movable contact 3 are connected. The lower end of the movable frame 30 is connected between them by a shaft 30a, and the movable frame 30 presses the movable contact 4 in a direction in which the movable contact 3 contacts the fixed contact 1. With this configuration, when the rear end portion 43a of the movable contactor 4 is pressed by the forced opening rod 7a, the opening spring 42 is compressed around the movable frame 30 as a fulcrum and rotated in the counterclockwise direction. Can work. The opening spring 42 has a larger spring force than the handle return spring 22.

The shield plate 9 is formed of an insulating member, is slidably supported in a guide groove 46 formed in the case 10 as shown in FIG. 2, and has a tip portion between the fixed contact 1 and the movable contact 3. It is located laterally and has an engaging hole 47 at its rear end, and the other end 35b of the operating link 35 is engaged with the engaging hole 47. This operating link 35 is cased by a fixed shaft 36 below the forced opening rod 7a.
It is rotatably held at 10. The operation link 35 has a V-shape and has a fixed shaft 36 at its bent portion, a winding portion of a return spring 37 is hooked on the fixed shaft 36, one end of the return spring 37 is locked to the bottom surface of the case 10, and the other end is fixed. Locked to actuation link 35, actuation link
35 is urged clockwise, and a cutout is provided at the rear end of the shield plate 9.
A rear end portion 43a of the movable contactor 4 is formed to form 65, and one end portion 35a of the operation link 35 is engaged with the front end thereof by the spring force of the return spring 37. The shield plate 9 is pulled by the return spring 37 by the operating link 35 and is positioned at the retracted position shown in FIG. The opening operation of the movable contact 4 causes the rear end portion 43a to rotate about the shaft 30a as a fulcrum, so that the one end portion 35a of the operation link 35 is rotated.
When the operating link 35 is pressed against the return spring 37, the operating link 35 rotates counterclockwise to move the shield plate 9 forward by the other end portion 35b, and the tip portion of the shield plate 9 causes the movable contact to move. It is located between 3 and the fixed contact 1 to shield them.

The fixed contactor 2 is arranged on the lower side of a partition plate 66 which partitions the lower side of the opening / closing / trip means 8 of the case 10, and the fixed contact 1 is opened / closed by being passed through a notch 67 formed in the partition plate 66. It faces the trip means 8 side. The base end portion of the fixed contactor 2 having the fixed contact point 1 at the tip end portion has an extending portion 49 extending partway toward the rear end portion of the movable contactor 4. As a result, when a current flows between the movable contact 4 and the fixed contact 2 while the movable contact 3 and the fixed contact 1 are in contact with each other, an electromagnetic repulsive force is generated, and in the case of an abnormal current, the electromagnetic repulsive force is large. In order to push up the movable contact 3, the opening spring 42 is compressed to open the movable contact 3 and assist the forced opening operation by the electromagnet 5. The base end portion of the fixed contact 2 extends from the extension portion 49 to the opposite side via the horizontal U-shaped bending portion 50, and the opposite side extension portion 44 has the curved portion 45 in the middle portion.
It is rotatably supported by being engaged with a fixed shaft 48 provided on the case 10, and a spring 56 is provided on the base end 49 ′ side of the fixed shaft 48 so that the fixed contact 1 is separated from the movable contact 3. While being urged, the base end portion 49 ′ is held in a fixed state by the plunger 51 of the polar electromagnet 50.

The polarized electromagnet 50 is provided to connect a remote control control and a timer circuit to have a timer function, and includes a plunger 51, a coil frame 55 around which a coil 52 is wound, yokes 53, 54, and yokes 53, 54. Permanent magnet 69 interposed between
(The magnetic poles are represented by N and S), and the first armature 51a of the plunger 51 contacts the yoke 53 and the second armature 51b.
The stable state is shown in FIG. The base end 49 ′ of the fixed contact 2 is engaged with the groove 57 of the protruding portion of the plunger 51, and the fixed contact 1 is held in the fixed state as the fixed contact 1 by the holding force of the permanent magnet 69 via the plunger 51. To be done. When the coil 52 of the polarized electromagnet 50 is energized, the plunger 51 moves to the opposite side due to excitation, and the fixed contact 2 rotates clockwise around the fixed shaft 48, so that the fixed contact 1 moves from the movable contact 2. Break apart.

In order to form an internal electric circuit of this circuit breaker, it is possible to connect between the bimetal 38 and the coil 32 of the electromagnet 5, between the coil 32 and the movable contact 4, and between the fixed contact 2 and the power supply side terminal 12, respectively. Tow wires 57-59 are connected. Therefore, the internal circuit is the load side terminal when viewed from the load side terminal 11 side.
11 → bimetal 38 → flexible electric wire 57 → coil 32 → flexible electric wire 58 → movable contact 4 → movable contact 3 → fixed contact 1 → fixed contact 2 → flexible electric wire 59 → power supply side terminal 12.

Incidentally, 60 is an energization indicator lamp whose example is a light emitting diode connected to the coil 52 of the polarized electromagnet 50 to display the energization state, and 61 is a window of the case 10 corresponding to the energization indicator lamp 60.
Translucent display board provided on 62, 63 is a gap adjusting screw
A cover plate provided in the window 64 of the case 10 corresponding to 39.

The operation of this circuit breaker will be described. That is, FIG. 1 shows the circuit breaker in the ON state, and FIG. 3 shows the OFF state. When the handle 6 is tilted counterclockwise from the OFF state to the state shown in FIG. 1, the handle 6 rotates about the fixed shaft 16 and the movable shaft 18 rotates counterclockwise. The operating link 19 moves downward while the operating shaft 20 slides on the latch link 23, so that the operating link 19 rotates in a vertical posture.
At this time, the handle return spring 22 is pulled. By the movement of the operating shaft 20, the movable frame 30 having the bearing recess 31 that engages with the operating shaft 20 is guided by the guide 29 and moves downward. The movable contact 4 is pressed by the lower end of the movable frame 30 and rotates counterclockwise from the state of FIG. 3, the movable contact 3 first contacts the fixed contact 1, and then the movable contact 3 contacts the fixed contact 1. In the contact state, the movable contact 3 rotates clockwise around the fixed contact 1 as a fulcrum, and the contact pressure is given by compressing the opening spring 42. At the same time, the movable contact 2 rolls on the surface of the fixed contact 1. By (rolling), the welding bridge is destroyed when contact welding occurs due to the arc at the time of turning on. Opening spring
Since 42 is compressed, its reaction force is applied to the operation link 19 via the movable frame 31, and when the movable shaft 18 crosses the reversing dead center intersecting the line connecting the fixed shaft 16 and the operating shaft 20, the opening The spring 42 pushes up the movable shaft 18 to urge the handle 6 in the tilted direction. The movable shaft 18 is locked by a stopper (not shown), and the handle 6 maintains the state shown in FIG. Therefore, the power supply side terminal
When 12 and the load side terminal 7 are connected to the load of the line, a current flows through the internal electric circuit.

When the handle 6 is tilted from the ON state of FIG. 1 to the state of FIG. 3, the movable shaft 18 rotates clockwise in the opposite direction to the above operation, and the actuating shaft 20 is latched by the biasing force of the opening spring 42.
It slides to 23 and moves upwards, the movable frame 30 moves upwards, and the movable contactor 4 performs a separating operation. When the curved portion 43 at the base end of the movable contactor 4 abuts on the lower end of the electromagnet 5, the movable contactor 4 rotates about the contact point as a fulcrum, and the movable contact 3 is largely separated from the fixed contact 1. Further, the operation link 35 operates in conjunction with the opening operation of the movable contactor 4, and the shield plate 9 intervenes between the movable contact 3 and the fixed contact 1.

FIG. 4 shows a state immediately after the short circuit current of the abnormal current flows, and FIG. 5 shows a state in which the opening / closing / trip means 8 has completed its operation. When a short-circuit current flows in the internal electric circuit, the electromagnet 5 operates to rotate the trip link 24 about the fixed shaft 25 and release the latch link 23. Then, the rear end portion 43a of the movable contactor 4 is pushed by the forced opening rod 7a, and the movable contactor 4 is rotated around the shaft 30a of the lower end portion of the movable frame 30 as a fulcrum against the spring force of the opening spring 42. The movable contact 3 is moved away from the fixed contact 1. The shield plate 9 is advanced by the opening operation of the movable contact 4. Then open and close by releasing the latch link 23.
The movable frame 30 operates so that the trip means 8 follows, and the movable contactor 4 trips. As a result, the shield plate 9 moves the movable contact 3 with the movable contact 3 slightly opened.
It is inserted between the fixed contact 1 and the fixed contact 1, and completely cuts off the arc generated when the contact is opened.

Following this operation, the trip operation by the third opening / closing / trip means 8 to reach the state of FIG. 5 is such that the trip link 24 rotates counterclockwise and its latch portion 24a moves to the lower end portion of the latch link 23. When you release from the side,
The latching link 23 rotates counterclockwise around the fixed shaft 16 by the force of the actuating shaft 20 pressing the latching link 23 based on the opening spring 42, and the actuating shaft 20 separates from the bearing recess 31 of the movable frame 30. . At the same time, the movable frame 30 moves upward due to the biasing force of the opening spring 42, the movable contact 4 moves apart accordingly, and the curved portion 43 of the movable contact 4 comes into contact with the lower end of the electromagnet 5 to move the curved portion 43. The movable contactor 4 rotates around the center, and the movable contact 3 further separates from the separated position by the forced opening. The open position of the movable contactor 4 is regulated by a stopper (not shown). Further, when the operating shaft 20 is separated from the bearing recess 31, it is not affected by the opening spring 42, so that the handle return spring 22
The movable shaft 18 rotates clockwise by the action of
Becomes neutral. The trip display is performed according to the neutral posture of the handle 6.

When the current in the internal electric circuit is cut off by trip opening, the attractive force of the electromagnet 5 is lost, and the movable portion 7 is returned by a return spring (not shown). However, the movable contactor 4 is maintained in the open state by the operation of the opening / closing / tripping means 8, and the shield plate 9 is also located between the movable contact 3 and the fixed contact 1.

For resetting after the repair of the short-circuit accident, the handle 6 in the neutral posture is tilted from the state shown in FIG. 5 to the off state shown in FIG. Since the movable shaft 18 rotates clockwise by the rotation of the handle 6, the operation link 19 is pulled up, and the operating shaft 20 engages with the bearing recess 31 of the movable frame 30. Also, the reset protrusion 68 of the handle 6
Causes the latch link 23 to rotate clockwise around the fixed shaft 18, the return spring 28 causes the trip link 24 to return, and the latch portion 24a is locked to the side surface of the lower end portion of the latch link 23. As shown in FIG. 3, the latch link 23 is brought into the latched state. This turns off.

Next, when an overcurrent flows in the internal electric path in the ON state, the movable part 7 of the electromagnet 5 does not operate because the return spring has a spring force larger than the attraction force, but the bimetal 38 is self-heated and bends, causing a gap. The tip of the adjusting screw 39 pushes the overcurrent response portion 26 of the trip link 24, which causes the trip link 24 to rotate and release the latch link 23.
The subsequent trip operation of the opening / closing / tripping means 8 is the same as described above.

When a current is applied to the coil 52 of the polar electromagnet 50 in the ON state of FIG. 1, the plunger 51 moves upward in FIG. 1, and the rear end portion 49 of the fixed contact 20 rotates clockwise. The fixed contact 1 is separated from the movable contact 3. Therefore, even if the handle 6 is in the ON position, the internal electric circuit is cut off.
On the contrary, even if the fixed contact 1 is in the state shown in FIG.
Since it is turned off by tilting the switch to the off position, the off priority is given in any case.

With this configuration, according to this embodiment, when an abnormal current such as a short-circuit current flows, the movable contactor 4 is forcibly opened by the movable portion 7 of the electromagnet 5 before the opening / closing / tripping means 8 trips. . The shield plate 9 enters between the fixed contact 1 and the movable contact 3 regardless of the operation of the opening / closing / tripping unit 8 in conjunction with the opening operation of the movable contactor 4. As a result, since there is no influence of the delay time due to the operation of the opening / closing / tripping means 8, the time from the occurrence of the abnormal current to the completion of the operation of the shield plate 9 can be shortened, and the arc breaking time can be shortened, so that a large breaking capacity is obtained. Can be realized.

According to the experiment, the time until the operation of the shield 9 was completed was within 2 ms. FIG. 7 shows an arc voltage waveform diagram at that time. Q ₅ is the estimated short-circuit current, Q ₆ is the breaking current, and Q ₇ is the contact arc voltage, but the breaking current is smaller than in Fig. 6, so the fixed contact 1, the movable contact 3, the case 10, the shield plate It can be seen that the damage due to the arc such as 9 is small.

Further, unlike the conventional case, since it is not necessary to increase the operating speed of the shield plate 9 by increasing the spring force of the opening spring 42, the operating load of the handle 6 is not increased.

Further, in this embodiment, after the trip link 24 is operated by the movable portion 7 of the electromagnet 5 to pull out the latch link 23,
Since the rear end portion 43a of the movable contactor 4 is pressed by the forced opening rod 7a, the load on the movable portion 7 during the forced opening of the movable contactor 4 is reduced, and the movable contactor 4 is forcibly opened reliably. You can

Further, since the shielding plate 9 is interlocked with the opening operation of the movable contact 4, the movable contact 3 is slightly opened.
The fixed contact 1 and the fixed contact 1 can be completely shielded, whereby the operating speed of the shield plate 9 can be increased and the current limiting performance can be further improved.

A second embodiment of the present invention is shown in FIGS. That is, although the electromagnet 5 also serves as the detection unit in the above-described embodiment, this embodiment uses the bimetal 38 for detecting an overcurrent as the detection unit. In this case, when the short-circuit current flows, the bimetal 38 operates later than the operation of the electromagnet 5. Therefore, when a short circuit occurs, the movable contact 4 is forcibly opened as shown in FIG. 10, and the shield plate 9 is moved to the movable contact 3 and the fixed contact 1.
11, the bimetal 38 actuates the trip link 24 to trip the latch link 23 and open the opening / closing / trip means 8 by tripping as shown in FIG. Others are first
This is the same as the embodiment.

Although the movable frame 30 and the movable contactor 4 are connected by the shaft 30a in the above embodiment, the movable frame 30 may be brought into contact with the movable contactor 4 only. Further, in the above-mentioned embodiment, the shield plate 9 is operated by the movable rod 7a via the operation link 35, but the shield plate 9 may be directly operated by the movable rod 7a.

Further, in this invention, the opening / closing / tripping means is not limited to the above embodiment. For example, the present invention can be applied to a slow-entry fast-breaking type and a reversing spring-type fast-breaking fast-entering type that are configured by the same type of link mechanism as the embodiment. Further, regarding the abnormal current, the above-mentioned embodiment targets the short-circuit current, but it can be applied to the overload current generated by the arc.

〔The invention's effect〕

According to the circuit breaker of the present invention, when an abnormal current, for example, a short circuit current flows, the movable contact is forcibly opened by the movable portion of the electromagnet before the opening / closing / trip means trips. The shield plate enters between the fixed contact and the movable contact without interlocking with the opening operation of the movable contactor by the operation of the opening / closing / tripping means. As a result, since there is no effect of delay time due to the operation of the opening / closing / tripping means, the time from the occurrence of abnormal current to the completion of the operation of the shield plate can be shortened, and the arc breaking time can be shortened, resulting in a large breaking capacity. can do. Moreover, since it is not necessary to increase the spring force of the opening spring of the opening / closing / tripping means, the operating load of the handle is not increased.

[Brief description of drawings]

FIG. 1 is a sectional view of an ON state of a first embodiment of the present invention,
2 is a partial perspective view showing the shield plate portion, FIG. 3 is a sectional view in an off state, FIG. 4 is a sectional view showing the operating state of the shield plate immediately after the trip, and FIG. 5 is a state in which the trip operation is completed. FIG. 6 is a cross-sectional view showing a conventional arc voltage waveform diagram,
FIG. 7 is an arc voltage waveform diagram of this embodiment, and FIG. 8 is a second diagram.
FIG. 9 is a sectional view showing an off state, FIG. 10 is a sectional view showing an operating state of the shielding plate immediately after the trip, and FIG. 11 is a sectional view showing a state where the trip operation is completed. FIG. 12 and FIG. 12 are partial cross-sectional views of a conventional example. 1 ... Fixed contact, 2 ... Fixed contact, 3 ... Moving contact,
4 ... movable contact, 5 ... electromagnet, 6 ... handle, 7
...... Movable part, 8 ...... Open / close / trip means, 9 ...... Shield plate

Claims (2)

[Claims] 1. A fixed contact having a fixed contact, a movable contact having a movable contact facing the fixed contact so as to be able to come into contact with and separated from the fixed contact, and the movable contact in conjunction with the opening operation of the movable contact. An arc-extinguishing shielding plate that enters between a fixed contact, an electromagnet that detects an abnormal current of a load, and forcibly opens the movable contact at a movable part when the abnormal current is detected, and the movable contact. Opening / closing the child contact with the handle and opening the tripped contact of the movable contact that has been forcibly opened in conjunction with the detection unit that detects an abnormal current of the load.
A forcible opening distance, in which the movable part directly acts on the movable contactor to force the contact to open, is at least a distance at which the shield plate can enter between the movable contact and the fixed contact. Circuit breaker. 2. The circuit breaker according to claim 1, wherein the detecting portion of the opening / closing / tripping means is the electromagnet.