JPS62163219A - Circuit breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 〔Technical field〕 This invention relates to a circuit breaker.

[Background technology]

A conventional example of cutting off and extinguishing the arc by inserting an arc-extinguishing shield plate between the movable contact and the fixed contact in the event of an abnormal current, such as a short circuit (Japanese Patent Laid-Open No. 196440/1983)
is shown in FIG. 12, but it had the following drawbacks. That is, since the shielding 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 section of the opening/closing/tripping means 104, the shielding plate 101 is moved between the fixed contact 102 and the movable contact 103, so that the shielding plate 101 is moved between the fixed contact 102 and the movable contact 103. There is a delay time of about 2 to 4 ms due to the operation of the link mechanism of the opening/closing/tripping means 104 until the contact 103 starts to open, and the movable contact 1
Approximately 3 to 5 minutes from the time 03 starts opening until the opening is completed
As, approximately 5 to 10 m3 is required from the occurrence of a short circuit until the shielding plate 101 completes its operation.

FIG. 6 shows an arc waveform when the spring force of the opening spring is set high and the shielding plate 101 completes its operation in about 5 ms. Ql is contact arc voltage, Q2 is breaking current,
Q3 is the estimated short circuit current.

In this way, even if the spring force of the opening spring is set high to operate the shielding plate 101, there is a delay of approximately 5 ms, and the short circuit current reaches its peak value, resulting in damage to the contacts due to arcing and Surrounding molded products and shielding plate 1
01 is severely damaged.

In addition, if the spring force of the opening spring is increased, the load for operating the handle increases, resulting in an operational burden.

As a result, there was a drawback that the time required for the shielding plate 101 to complete its operation could not be shortened, and a large breaking capacity could not be obtained.

[Purpose of the invention]

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

[Disclosure of the Invention] The circuit breaker of the present invention includes a fixed contact having a fixed contact, a movable contact having a movable contact that opens and closes with respect to the fixed contact, and a circuit breaker having a fixed contact that opens and closes with respect to the fixed contact. an electromagnet that detects the current and forcibly opens the movable contact with a movable part; and f) between the movable J contact and the fixed contact, which are opened by the forced opening in conjunction with the operation of the electromagnet. An arc-extinguishing shield plate is inserted, and the movable contact is opened and closed by a handle, and the forcibly opened movable contact is trip-opened in conjunction with a detection unit that detects abnormal current in the load.・It is equipped with a trip means.

According to the configuration of this invention, the abnormality T;,? A: For example, when a short circuit current flows, the movable contact is forcibly opened by an electromagnet before the switching/tripping means trips. At the same time, the shielding plate is inserted between the fixed contact and the movable contact in conjunction with the operation of the electromagnet and without the operation of the opening/closing/tripping means. As a result, there is no effect of delay time caused by the operation of the opening/closing/tripping means, so the time from when an abnormal current occurs until the shielding plate completes its operation can be shortened, and the arc breaker time can be shortened, resulting in a large breaker capacity. It can be realized. Moreover, since there is no need to increase the opening spring of the opening/closing/tripping means, there is no need to increase the operating load of the handle.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 7. That is, this circuit breaker includes a fixed contact 2 having a fixed contact 1, a movable contact 4 having a movable contact 3 that opens and closes with respect to the fixed contact 1, and a movable part 7 that detects an abnormal current of the load. an electromagnet 5 for forcibly opening the movable contact 4; and an arc-extinguishing electrode inserted between the movable contact 3 and the fixed contact 1, which are opened by the forcible opening in conjunction with the operation of the electromagnet 5. The shielding plate 9 and the movable contact 4 are opened and closed by the handle 6, and the movable contact 4, which is forcibly opened, is trip-opened in conjunction with a detection unit that detects abnormal current in the load. means 8.

In FIG. 1, 10 has an opening (not shown) on the side surface (in a direction perpendicular to the paper surface of FIG. 1) for incorporating components;
The case has a structure of poles, and when configuring a multi-pole circuit breaker, the cases 10 are arranged in parallel and connected by passing a caulking pin (not shown) through the connection hole 13. 11 is a load side terminal provided at one end of the case 10, and 12 is provided at the other end of the case 10. it
'fi side terminal, 14 is a case mounting groove.

The opening/closing/tripping means 8 includes a handle 6, a frame 15, an operation link 19, an operating shaft 20, and a movable frame 30.
, a launch link 23 , a trip link 24 , an opening spring 42 , and the above-mentioned detecting section whose embodiment is an electromagnet 5 . The frame 15 is held within the case 10. The handle 6 is rotatably provided at the upper end of the frame 15 in FIG.
A part of the case 10 is exposed through the handle hole 17 on the top surface of the case 10.
A reset protrusion is formed on the inside of the 6th.

A movable shaft 18 is provided at the inner end of the handle 6.
One end of the operating link 19 is connected to the link 8, and the operating shaft 2 is connected to the other end.
0 is concatenated. Further, a handle return spring 22 having a tensile action is suspended between the movable shaft 18 and a spring receiver 21 provided below the handle 6 of the frame 15, and is attached so that the handle 6 is in the neutral position shown in FIG. It is strong. The upper end of the latch link 23 is rotatably connected to the fixed shaft 16, and the operating shaft 20 is slidably abutted on one side of the lower end of the launch link 23. A trip link 24 is rotatably provided on the frame 15 at a position opposite to the operating shaft 20 of the latch link 23 by a fixed shaft 25.

This trip link 24 has a latch portion 24a at the tip,
It has a short-circuit response section 27 in the middle, an overcurrent response section 26 extending upward from the fixed shaft 25, and a return spring 28. The return spring 28 has a wound portion supported by the fixed shaft 25, one end of which engages with the overcurrent response section 26, and the other end of which engages with the frame 15 to rotate the trip link 24 clockwise in FIG. It is biased and positioned at the position shown in FIG. 1 by a stopper (not shown) provided on the frame 15. Further, this state is a launch state in which the latch portion 24a abuts and locks the lower end of the launch link 23, and prevents the latch link 23 from rotating counterclockwise about 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 J frame 30 inserted between the guides 29 is guided so as to be slidable in the vertical direction in FIG. The movable frame 30 has a bearing recess 31 (see FIG. 5) formed at its upper end, and the bearing can be engaged with the recess 31 to prevent the operating shaft 20 from moving downward. .

The electric power stone 5 is of a plunger type, and includes a movable part 7 which is the plunger, a coil cylinder 33 having the movable part 7 inside, and a yoke 4 spanning both ends of the coil cylinder 33.
0, the coil 32 wound around the coil tube 33 inside the yoke 40, the fixed core 4I facing the movable part 7 within the coil tube 33, and the fixed core 4I interposed between the movable part 7 and the fixed core 41. It is composed of a return spring (not shown) and an operating link 35.

The yoke 40 is fixed below the trip link 24 of the frame 15. The movable part 7 is provided with a movable rod 7a that penetrates the fixed iron core 41, either integrally or separately.
A forced opening step 7b is formed in the middle part of a, and a collar-shaped engagement part 34 is provided at the upper end of the movable part 7. 0 actuation links 3 facing each other so as to engage with the short-circuit response section 27
5 is rotatably held in the case 10 by a fixed shaft 36 below the movable rod 7a. This operating link 35 has an L-shape and has a fixed shaft 36 at its bent part, a winding part of a return spring 37 is hung 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. is locked to the operating link 35, the operating link 35 is biased clockwise, and the lower end of the movable rod 7a is pressed upward by one end 35a of the operating link 35 due to the spring action, and the stepped portion of the movable portion 7 is The coil cylinder 33 is positioned by being engaged with the inner step at the upper end thereof.

Note that the return spring (not shown) can also be used as the return spring 28 or 37.

The electromagnet 5 detects short-circuit current by setting the spring force of a return spring (not shown), and a bimetal 38 is provided in the case 1o to detect overcurrent. The base end of the bimetal 38 is fixed to the load-side terminal 11, and a gap adjustment screw 39 is provided at the distal end, with the distal end of the gap adjustment screw 39 facing the overcurrent response section 26.

The movable contactor 4 is supported in a state where the middle part is urged upward by an opening spring 42, the movable contact 3 is fixed to the tip part, and the rear end part 43a is attached to the forced opening step part 7b. 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 the opening spring 42
The lower end of the movable frame 30 is connected between the shaft 30 and the movable contact 3.
a, and the movable frame 30 presses the movable contact 4 in the direction in which the movable contact 3 contacts the fixed contact 1. With this configuration, the movable contactor 4 is connected to the rear end 4 by the movable rod 7a.
When 3a is pressed, the opening spring 4 uses the movable frame 30 as a fulcrum.
2 is compressed and rotated counterclockwise, thereby allowing the opening operation.

Note that the spring horn of the opening spring 42 is set larger than that of the handle return spring 22.

The shielding plate 9 is made of an insulating material, and is slidably supported in a guide groove 46 formed in the case 10, as shown in FIG. The engagement hole 4 is located on the side and has an engagement hole 47 at the rear end.
7 is engaged with the other end 35b of the operating link 35. Also, a notch 65 is formed at the rear end of the shield Fi9, through which the rod 7a passes. The shielding plate 9 is pulled by the operating link 35 by the return spring 37 and is located in the retracted position shown in FIG. Due to the operation of the electromagnet 5, the movable rod 7a moves downward, and the link 35 is released into the return spring 37.
When pressed against this, the operating link 35 rotates counterclockwise and moves the shielding plate 9 forward with the other end 35b.
The tip of the shielding plate 9 is located between the movable contact 3 and the fixed contact 1 to shield both.

This operation of the shield plate 9 is performed after the movable contact 4 is forcibly opened. For this reason, the operation timing is set so that the movable contact 4 is first forcibly opened by the operation of the movable part 7 of the electromagnet 5, and then the shielding plate 9 is operated. Also open/close/
The tripping operation of the tripping means 8 is also performed after the movable contact 4 is forcibly opened, but considering the delay in the operation of the link mechanism, IC,
The electromagnet 5 first removes the latch link 23, and then the forced opening step 7b presses the rear end 43a of the movable contact 4.
It is possible to reduce the load applied to the

The fixed contact 2 is arranged on the lower side of a temporary partition 66 that partitions the lower side of the opening/closing/tripping means 8 of the case IO,
The fixed contact 1 passes through a notch 67 formed in the partition plate 66 and opens toward the opening/closing/trip means 8 side. The base end of the fixed contact 2 having the fixed contact 1 at its tip end has an extension part 4 that extends halfway toward the rear end of the movable contact 4.
It has 9. 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, 1! Magnetic repulsion is generated, and in the case of an abnormal current, the electromagnetic repulsion becomes large and pushes up the movable contact 3, so the opening spring 42 is compressed and the movable contact 3 opens, causing 1! Assists the forced opening operation by the magnet 5. The base end portion of the fixed contact 2 extends from the extending portion 49 to the opposite side via a horizontal U-shaped bent portion 50, and this opposite side extending portion 44 has a curved portion 45 in the middle portion, A fixed shaft 4 provided on the case 10 is engaged with and rotatably supported, and a spring 56 is provided on the proximal end 49' side of the fixed shaft 48 to connect the fixed contact l to the movable contact 3.
The proximal end portion 49' is held in a fixed state by a plunger 51 of a polarized electromagnet 50.

The polar magnet 50 is provided to provide a timer function by connecting a remote control and a timer circuit, and the plunger 51. Coil frame 5 wrapped with coil 52
5. York 53.54. and a permanent magnet 69 interposed between the yaws 53 and 54 (%Sl m is expressed in N and S)
The first armature 51a of the plunger 51 is in contact with the yoke 53, and the second armature 51b is in contact with the yoke 53.
The state shown in FIG. 1 in which the contact point 4 is in contact is defined as a stable state. The fixed contact 20 is attached to the protrusion 7 (857) of the plunger 51.
The base end portion 49' is engaged, and the fixed contact 1 is maintained in a fixed state as the fixed contact 1 by the holding force of the permanent magnet 69 via the plunger 51. Polarized electric K1 stone 50 coil 52
When energized, the plunger 51 moves to the opposite side due to excitation, and the fixed shaft 1 of the fixed contact 2 separates from the movable contact 2.

In order to form an internal electric path of this circuit breaker, the circuit breaker is constructed 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.
Flexible electric wires 57 to 59 are connected between them, respectively. Therefore, when viewed from the load side terminal 11 side, the internal electric circuit is from load side terminal 11 to bimetal 38 to flexible electric wire 57 to
Coil 32 - Flexible wire 58 - Movable contact 4 - Movable contact 3 - Fixed contact 1 - Fixed contact 2 - Flexible wire 59 - Power supply side terminal 12.

In addition, 60 is an energization indicator lamp which is an example of a light emitting diode connected to the coil 52 of N polarity and electromagnet 0 to indicate the energization state, and 61 is provided in the window 62 of the case 10 in correspondence with the energization indicator lamp 60. The transparent display plate 63 is a cover plate provided on the window 64 of the case 10 in correspondence with the gap adjustment screw 39.

The operation of this circuit breaker will be explained.

That is, FIG. 1 shows the circuit breaker in the on state, and FIG. 3 shows the circuit breaker in 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. Since the operating shaft 20 of the operating link 19 moves downward while sliding on the latch link 23, the operating link 19 rotates in a direction in which it assumes a vertical position. At this time, the handle return spring 22 is pulled. As the operating shaft 20 moves, the bearing engaged with the operating shaft 20 moves the movable frame 30 having the recess 31 downward as it is guided by the guide 29. Movable contact 4 is movable frame 3
0, the movable contact 3 contacts the fixed contact 1, and then the movable contact 3 contacts the fixed contact 1, and the movable contact 3 rotates counterclockwise from the state shown in Fig. 3. The child 3 rotates clockwise around the fixed contact l, and the opening spring 4
By compressing 2, contact pressure is applied, and at the same time, the movable contact 2 rolls on the surface of the fixed contact 1, thereby destroying the welding bridge when contact welding occurs due to the arc at the time of closing. Furthermore, since the opening spring 42 is compressed, the reaction force is transmitted to the operation link 19 via the movable frame 31.
When the movable shaft 18 crosses the reversal dead center where the movable shaft 18 intersects the line connecting the fixed shaft 16 and the operating shaft 2o, the opening spring 42 pushes up the movable shaft 18 and biases the handle 6 in the direction in which it falls. .

The movable shaft 18 is engaged with a not-shown shaft, and the handle 6 maintains the state shown in FIG. Therefore, when the power supply side terminal 12 and the load side terminal 7 are connected to the load of the line, a current flows through the internal circuit.

When the handle 6 is tilted from the ON state shown in FIG. 1 to the state shown in FIG. 23 and moves upward, the movable frame 30 moves upward, and the movable contact 4 performs an opening/separating operation. When the curved portion 43 at the base end of the movable contact 4 comes into contact with the lower end of the electromagnet 5, the movable contact 4 rotates about the contact point as a fulcrum, and the movable contact 3 separates greatly from the fixed contact 1.

Figure 4 shows the abnormality [the state immediately after the short circuit current flows,
FIG. 5 shows a state in which the opening/closing/tripping means 8 has completed its operation. When a short circuit current flows through the internal circuit, the following three operations occur due to the operation of the electromagnet 5. First, Trip Link 2
4 around the fixed shaft 25 to release the launch link 23. Next, the rear end 43a of the movable contact 4 is pushed by the forced opening step 7b, and the movable contact 4 is moved around the lower end of the movable frame 30 around the shaft 30a as a fulcrum against the spring force of the opening spring 42. is rotated, and the movable contact 3 is separated from the fixed contact 1.

Furthermore, the operating link 35 is rotated at the lower end of the movable rod 7a,
The shielding plate 9 is advanced.

As a result, at the same time as the movable contact 3 opens, the temporary shield 9 is inserted between the movable contact 3 and the fixed contact 1 to cut off the arc generated when the contact is opened.

Following this operation, the third opening/closing process that leads to the state shown in FIG.
The tripping operation by the tripping means 8 is performed when the trip link 24 rotates counterclockwise and the launch portion 24a performs a releasing operation to move away from the side surface of the lower end of the launch link 23. The force of pressing the latch link 23 causes the launch link 23 to move to the fixed shaft 16.
The operating shaft 20 rotates counterclockwise around the movable frame 30.
The bearing is separated from the fourth part 31. At the same time, the movable frame 30 moves upward due to the biasing force of the opening spring 42, and the movable contact 4 moves to open and separate, causing the curved portion 43 of the movable contact 4 to contact the lower end of the electromagnet 5, causing the curved portion 43 to move upward. The movable contact 4 rotates around the center, and the movable contact 3 further opens and opens from the forced opening position. The open position of the movable contactor 4 is regulated by a stopper (not shown). Furthermore, when the operating shaft 20 moves away from the bearing recess 31, the shadow of the opening spring 42
Therefore, the movable shaft 18 rotates clockwise due to the action of the handle return spring 22, and the handle 6 assumes a neutral position. A trip display is performed with this neutral position of the handle 6.

When the current in the internal circuit is cut off by trip opening,
Since the attractive force of the magnet 5 disappears, the movable part 7 returns to its original position by a return spring (not shown), and at the same time, the temporary shield 9 returns to its original position. However, the movable contact 4 is maintained in an open state by the operation of the opening/closing/tripping means 8.

To reset after repairing a short-circuit accident, move the handle 6 in the neutral position from the state shown in FIG. 5 to the OFF state shown in FIG. 3. Rotation of the handle 6 causes the movable shaft 18 to rotate clockwise, so the operating link 19 is pulled up and the operating shaft 20 is moved to the movable frame 30.
The bearing engages in the recess 31. Further, the reset protrusion 68 of the handle 6 causes the launch link 23 to rotate clockwise about the fixed shaft 18, and the return spring 28 causes the trip link 24 to return, so that the launch portion 24a
The launch link 23 is held in the latched state as shown in FIGS. 1 and 3. This turns it off.

Next, when an overcurrent flows in the internal circuit in the on state,
The movable part 7 of the electromagnet 5 does not operate because the return spring 37 has a spring force greater than the attraction force, but the bimetal 38 is self-heated and bent, and the tip of the gap adjustment screw 39 causes an overcurrent in the trip link 24. The response unit 26 is pressed, which causes the trip link 24 to rotate and launch the launch link 23.
to be released. The subsequent tripping operation of the opening/closing/tripping means 8 is the same as described above.

In addition, in the on state shown in FIG. 1, the coil 52 of the polarized electromagnet 50
When current is applied to , the plunger 51 moves upward in FIG. 1, the rear end portion 49 of the fixed contact 2 rotates clockwise, and the fixed contact 1 separates 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. 1, it is turned off by tilting the handle 6 to the off position, so in either case, priority is given to off.

Because of this configuration, according to this embodiment, when an abnormal current such as a short circuit current flows, the opening/closing/tripping means 8
The movable contactor 4 is forcibly opened by the electromagnet 5 before the tripping operation occurs. At the same time, it opens and closes in conjunction with the operation of the electromagnet 5.
The shielding plate 9 is inserted between the fixed contact 1 and the movable contact "3-" without being affected by the operation of the tripping means 8. As a result, there is no influence of delay time caused by the operation of the opening/closing/tripping means 8, so that abnormal current The time from the occurrence of the arc to the completion of the operation of the temporary shield 9 can be shortened, and the arc cutoff time can be shortened, so a large cutoff capacity can be realized.

According to experiments, the time required for the shielding plate 9 to complete its operation was within 2 ms. FIG. 7 shows the arc voltage waveform diagram at that time, where Q is the estimated short circuit T4. Flow, Q.

is the breaking current, and Q7 is the contact arc voltage, but since the breaking current is smaller compared to FIG. 6, the fixed contact 1.
Movable contact 3. Case 10. It can be seen that the damage caused by the arc to the shielding plate 9, etc. is small.

Further, unlike in the prior art, there is no need to increase the operating speed of the shielding plate 9 by increasing the spring force of the opening spring 42, so there is no need to increase the operating load on the handle 6.

In this embodiment, after the trip link 24 is operated by the movable part 7 of the Ql magnet 5 to trip the launch link 23, the rear end 43 of the movable armature 4 is operated by the forced opening step part 7b.
Since the shield plate 9 is further actuated by pressing a, the load on the movable part 7 when the movable contact 4 is forcibly opened is reduced, and the movable contact 4 can be reliably forcibly opened. In addition, there are 7 detection units that detect abnormal current! Since the magnet 5 is used for both purposes, the configuration is simplified, and there is no lunch exception and 1 forced opening.

And the timing 1 of the shielding operation by the shielding plate 9 is easy to take.

A second embodiment of the invention is shown in FIGS. 8-11. That is, in the above embodiment, the electromagnet 5 also serves as the detection section, but in this embodiment, the bimetal 38 for detecting overcurrent is used. In this case, when a short circuit current flows, the bimetal 38 operates later than the electromagnet 5 operates. Therefore, when a short circuit occurs, the movable contact 4 is forcibly opened as shown in FIG. 10, and the shield 47i9 enters between the movable contact 3 and the fixed contact 1, and then the bimetal
8 actuates the trip link 24, trips the launch link 23, and trips the opening/closing/tripping means 8. The rest is the same as the first embodiment.

In the above embodiment, the movable frame 30 and the movable contact 4 were connected by the shaft 30a, but the movable frame 30 may simply be brought into contact with the movable contact 4. Further, in the above embodiment, the movable rod 7a operates the shielding plate 9 via the operating link 35, but the movable rod 7a may directly operate the shielding plate 9.

Further, in the present invention, the opening/closing/tripping means is not limited to the above embodiment. For example, it can be applied to a personal quick-acting type constructed with the same type of link mechanism as in the embodiment and a quick-acting quick-acting type using a reversal spring. Regarding abnormal current, although the above embodiment deals with short circuit current, it can also be applied to overload current where arcing occurs.

[Effects of the Invention] According to the circuit breaker of the present invention, when an abnormal current such as a short circuit current flows, the movable contact is forcibly opened by the electromagnet before the switching/tripping means trips. At the same time, the shielding plate is inserted between the fixed contact and the movable contact in conjunction with the operation of the electromagnet and without the operation of the opening/closing/tripping means.

As a result, there is no apparent delay time due to the operation of the opening/closing/tripping means, so the time from when an abnormal current occurs until the shield plate completes its operation can be shortened, and the arc breaker time can be shortened, resulting in a large breaker capacity. be able to. Moreover, since there is no need to increase the size of the opening spring of the opening/closing/tripping means, there is an effect that the operating load of the handle does not increase.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the first embodiment of the present invention in the on state;
Figure 2 is a partial perspective view of the shield plate, Figure 3 is a cross-sectional view of the off state, Figure 4 is a cross-sectional view of the shield plate operating immediately after a trip, and Figure 5 is a state after the trip operation is completed. 6 is a cross-sectional view showing the arc voltage waveform diagram of the conventional example,
Fig. 7 is an arc voltage waveform diagram of this embodiment, and Fig. 8 is a diagram of the arc voltage waveform of this embodiment.
9 is a sectional view of the embodiment in the on state, FIG. 9 is a sectional view of the off state, FIG. 10 is a sectional view showing the operating state of the shield plate immediately after tripping, and FIG. 11 is a sectional view showing the state where the tripping operation is completed. 12 are partial sectional views of the conventional example. DESCRIPTION OF SYMBOLS 1... Fixed contact, 2... Fixed contact, 3... Movable contact, 4... Movable contact, 5... Electromagnet, 6...
/”% bundle, 7... Movable part, B... Opening/closing/tripping means, 9... Shielding cross section Figure 2 - Pt I'+fl (msec) Figure 6 □ Time (msec) Figure 7 Figure 12

Claims (2)

[Claims] (1) A fixed contact having a fixed contact, a movable contact having a movable contact that opens and closes with respect to the fixed contact, and an electromagnet that detects abnormal current in the load and forcibly opens the movable contact with a movable part. and an arc-extinguishing shield plate inserted between the movable contact and the fixed contact, which are opened by the forced opening in conjunction with the operation of the electromagnet, and the movable contact is opened and closed by a handle. A circuit breaker comprising an opening/closing/trip means for tripping and opening the forcibly opened movable contact in conjunction with a detection unit that detects an abnormal current in a load. (2) The circuit breaker according to claim (1), wherein the detection section of the opening/closing/tripping means is the electromagnet.