JP3518101B2 - Circuit breaker - Google Patents

Description

BACKGROUND OF THE INVENTION [0001] [Technical Field of the Invention The present invention, over the circuit breaker
Direct heat that flows the main circuit current in the bimetal of the current trip device
The present invention relates to the improvement of a thermal- type trip unit. 2. Description of the Related Art FIGS. 14 and 15 show a conventional circuit breaker disclosed in Japanese Utility Model Publication No. Sho 56-20917, for example, and FIG. 14 shows a main part of a thermal release device. Perspective view,
FIG. 15 is a partially enlarged side view showing details of a joint portion between the bimetal and the support conductor. In these figures, reference numeral 2 denotes a frame, and two plates 2a and 2b each having a shape as shown in the drawing.
Are arranged in parallel, and the lower part thereof is connected, and has a mover mounting part 2c in the front part of the figure. The frame 2 is fixed to a base formed of a synthetic resin (not shown) with screws. [0003] Reference numeral 4 denotes a mover.
b and the movable contact 4c (FIG. 14), and is made of an elastic plate-shaped copper alloy material. The extension 4b extends from the plate-like support 4a to the left in the figure, and the movable contact 4c is fixed to the extension 4b. In addition, 4d is the support portion 4a
15 and is opposed to a bimetal-side joint end 6c of the bimetal 6, which will be described later.
The lower surface side of the supporting portion 4a in the figure is fixed to the mover mounting portion 2c of the frame 2 by brazing, and the extending portion 4b is pressed downward by a pressing plate (not shown) and elastically deformed to come into contact with a fixed contact (not shown). Has been. [0004] Reference numeral 6 denotes a bimetal having a thermally responsive portion 6a and a bent portion 6b, which is formed by bending a plate-shaped member as shown to form a thermally responsive portion 6a and a bent portion 6b. (FIG. 15). Reference numeral 6c denotes a bimetal-side joint end on the left side of the bent portion 6b. The lower surface side of the plate-shaped bent portion 6b is brazed to the support portion 4a of the mover 4 with the silver solder 8, and at the left portion in FIG. 15 of the joint portion where the bent portion 6b and the support portion 4a are joined. The bimetal-side joining end 6c and the supporting end 4d face each other.
Reference numeral 8a denotes an outflow portion where the silver solder has flowed out and solidified during brazing. A flexible copper stranded wire (not shown) having sufficient flexibility is brazed to a portion A slightly above the central portion of the thermally responsive portion 6a of the bimetal 6 in FIG. 14, and not shown via this soft copper stranded wire. Connected to terminal device. The current of the main circuit is changed from the part A of the bimetal 6 to the thermally responsive part 6a, the bent part 6b, the support part 4a of the mover 4, the extending part 4b, the movable contact 4
c, flows to a fixed contact (not shown). Next, the operation will be described. When the main circuit current flows through the bimetal 6 via the flexible conductor, the distal end of the thermally responsive portion 6a bends in the direction of arrow B in FIG. By bending the heat responsive portion 6a, a tripping rod (not shown) is rotated clockwise, that is, in the tripping direction. When the tripping rod is rotated clockwise, the locking mechanism (not shown) is released, and the movable portion 4c is returned to the original state by the elastic force from the state in which the extension portion 4b is pressed, so that the movable contact 4c moves upward in the figure. It moves and separates from a fixed contact (not shown). The conventional circuit breaker as described above has a direct heat type structure in which the current of the main circuit flows directly through the inside of the bimetal 6 in order to obtain the bimetal bend. ing. Therefore, when a very large current flows as in the case of a short circuit, there is a problem that the bimetal 6 is abnormally overheated and permanently deformed. In particular, the current is U-turned between the bent portion 6b of the bimetal 6 and the support portion 4a of the mover 4. Therefore, as shown by an arrow C in FIG. 15, current concentration occurs at the bimetal-side joining end 6c and the supporting end 4d of the mover 4, so that there is a high possibility that abnormal overheating will occur. Further, there is a problem that the permanent deformation of the bimetal caused by abnormal overheating of the bimetal-side joining end 6c greatly deteriorates the performance of the bimetal. [0008] The support 4a of the mover 4 and the bent portion 6b of the bimetal 6 are joined by brazing.
During brazing, the melted brazing material flows out to form an outflow portion 8a. In addition, since the position at which the brazing material flows out and forms the outflow portion 8a is not constant, there is a problem that the fulcrum of the operation of the thermally responsive portion 6a of the bimetal 6 fluctuates, and the operation characteristics of the bimetal 6 are not stable. SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and alleviates the concentration of a current flowing through a bimetal to a local area. The purpose is to get. It is another object of the present invention to obtain a circuit breaker having a simple configuration and a stable thermal tripping characteristic. [0010] A circuit breaker according to the present invention.
The container has a support part and an extension part extended from the support part.
And fixed to the base while the main circuit current flows.
One end of the supporting conductor is connected to the extended portion of the supporting conductor so as to be able to conduct electricity.
Generated by the main circuit current flowing through itself
The opening and closing mechanism is actuated by the other end deformed by heat.
To release the contacts through which the main circuit current flows.
So that it is in the vicinity of the support portion of the support conductor
And the opposite side from the bimetal side provided in the extension section
A through hole is formed through the support conductor, and the bimetal
This alleviates the concentration of the current flowing into the device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment of the Invention FIG. 1 is a cross-sectional view showing a circuit breaker according to an embodiment of the present invention, FIGS. 2 to 4 show details of a thermal trip device in FIG. 1, FIG. 2 is a perspective view, and FIG. FIG. 4 is a plan view, and FIG. 4 is a side view. In these figures, reference numeral 30 denotes a housing, a base 30a and a cover 30.
b, and both are formed of a synthetic resin. 32
Is a fixed contact, and the fixed contact 32a is brazed. Reference numeral 34 denotes a movable contact, to which a movable contact 34a is joined, and which is opposed to the fixed contact 32 so as to form a pair. The lower end of the movable contact 34 is connected to a shunt terminal 38 via a flexible conductor 36 having sufficient flexibility. Reference numeral 40 denotes an opening / closing mechanism, which is a cradle 40.
a, a latch 40b, and a trip bar 40c. The trip bar 40c is supported by a plate-like support member (not shown) provided on the base 30a so as to be rotatable in the direction of arrow F about the point E in FIG.
Reference numeral 42 denotes a handle, which is fitted to the opening / closing mechanism 40. Reference numeral 44 denotes an overcurrent trip device, which comprises an electromagnetic trip device 50 and a thermal trip device 60 and is housed in a housing portion formed by the base 30a and the cover 30b. The overcurrent trip device 44 is connected to the latch 40b of the opening / closing mechanism 40 via the trip bar 40c.
To work. Electromagnetic trip device 50
Has an electromagnetic coil 52 and an amateur 54. The electromagnetic coil 52 includes an iron core 52a, a coil 5
2b, a yoke 52c, and a support plate 52d. The coil 52b is wound around an iron core 52a, and a yoke 52c is provided at both ends (a direction perpendicular to the plane of FIG. 1) of the iron core 52a, and a support plate 52d is welded to the yoke 52c. One terminal of the coil 52b is connected to an external connection terminal 70 described later, and the other terminal is connected to a bimetal 64 described later via a flexible stranded wire 58. The amateur 54 is formed by punching from a steel plate, and is rotatably supported in the direction of arrow D by a pin 56 provided on the support plate 52d.
70 is an external connection terminal for connecting an electric wire to the circuit breaker from outside. Next, referring to FIGS. 2 to 4, the detailed structure of the thermal traction device 60 will be described. Reference numeral 62 denotes a support conductor, which has a support portion 62a and an extension portion 62b, and is formed of a copper plate having sufficient rigidity. Plate-shaped support part 62
“a” has an enlarged portion 62c wider than the width of the extending portion 62b at the center. On the enlarged portion 62c, a rectangular mounting surface 62d to be joined to a bimetal 64 described later is provided so as to slightly project upward by punching. Extension part 62b
4, is slightly linearly extended rightward from the support portion 62a as shown in FIG. 4, and then is stepped and supported so as to be slightly higher than the base 30a due to the attachment to the base 30a (FIG. 1). It is bent and formed so as to be parallel to the portion 62a, and is connected to the shunt terminal 38 (FIG. 1). 6
2e is an end of the right side of the mounting surface 62d in FIG. Adjacent to the mounting surface end 62e, the extension 62
2b is provided with a through hole 62f as a current concentration reducing means penetrating from the upper side to the lower side in FIG. Through hole 62f
Is long in the width direction of the support portion 62a as shown in FIG. 3, and its width Wh is the width Wb of the bent portion 64b of the bimetal 64.
And the corners are rounded. The extending portion 62b is provided with a screw hole 62g by burring, and is fixed to the base 30a together with the shunt terminal 38 by a bolt (not shown). Reference numeral 64 denotes a bimetal, and a heat responsive portion 64a
And a bent portion 64b as a joining portion, and two metal plates having different coefficients of thermal expansion are bonded to each other to form a plate shape as shown in the figure. The bimetal 64 is bent in two stages with the high expansion side inside the bend (to the left in FIG. 4), and each of the linear portion and the bent portion 64b of the plate-like heat responsive portion 64a.
Are substantially perpendicular to each other (FIG. 4). 6
Reference numeral 4c denotes a bimetal-side joining end portion on the right side of the bent portion 64b. The lower surface of the bent portion 64b is
The second mounting surface 62d is brazed by silver brazing. In the right portion in FIG. 4 of the joint portion where the bent portion 64b and the support portion 62a are joined, a bimetal-side joint end 64
c and the mounting conductor end 62 e of the support conductor are opposed to each other. Reference numeral 66 denotes a copper plate, which is brazed to the free end of the bimetal 64 above the thermally responsive portion 64a. The flexible plate 58 from the coil 52b is attached to the plate 66.
Are brazed (FIG. 1). 68 is an adjusting screw,
It is screwed to the free end side of the heat responsive portion 64a as shown in FIG. The adjustment screw 68 is not shown in FIGS. 3 and 4. The main circuit current is applied to the fixed contact 32, the movable contact 34, the flexible conductor 36, the shunt terminal 38, the extending portion 62b of the support conductor 62, the mounting surface 62d, the bent portion 64b of the bimetal 64, and the thermally responsive portion 64a. The flexible stranded wire 58 flows from the electromagnetic coil 52 to the external connection terminal 70. Next, the operation will be described. If a large current flows through the circuit breaker due to an accident in the distribution line, etc., if the large current is less than a predetermined multiple of the rated current set in the circuit breaker, for example, if it is less than 10 times, the thermal dynamics release The device 60 operates. The bimetal 64 is heated and deformed by the circuit current flowing through the thermally responsive portion 64a, and the tip of the thermally responsive portion 64a moves in the direction of arrow D in FIG. Thermal response part 64
The adjustment screw 68 provided at the tip of the a
0c, the trip bar 40c rotates about the rotation center E in the direction of arrow F. By the rotation of the trip bar 40c, a latch (not shown) that is latching the latch 40b is released, and the cradle 40a operates to separate the movable contact 34 from the fixed contact 32. If the large current caused by an accident or the like is, for example, 10 times or more the rated current, the coil 52b
The magnetic force induced by the magnetic force attracts the amateur 54 and FIG.
In the direction of arrow D. When the amateur 54 rotates, the trip bar 40c is similarly rotated in the direction of arrow F, the circuit breaker trips, the movable contact 34 is separated from the fixed contact 32, and a known breaking operation is performed. It is. In the thermal exfoliation device 60 constructed as described above, as shown in FIG. 4, a through hole 62f is provided adjacent to a mounting surface end 62e which is a right end of the mounting surface 62d of the support conductor 62. Have been. Due to the presence of the through-hole 62f, the main circuit current flows, as shown by the arrow G in FIG. 3, both ends 64ba, 63 of the bent portion 64b of the bimetal 64.
bb and the enlarged portion 62 of the support portion 62a of the support conductor 62
c. Therefore, current does not concentrate on the bimetal-side joint end 64c of the bimetal 64,
Even if a very large current flows like a short circuit accident,
Permanent deformation due to abnormal overheating of the bimetal 64 can be prevented. Further, since the through hole 62f is provided adjacent to the end face 62e of the mounting surface, even if the brazing material flows out during the brazing, it flows into the through hole 62f. Therefore, the mounting surface end 62
Since e does not protrude significantly to the right of e, the position of the fulcrum of the thermally responsive portion 64a of the bimetal 64 does not change, and stable operation characteristics can be obtained. Embodiment 2 of the Invention FIG. 5 is a plan view showing a main part of a thermal traction device according to another embodiment of the present invention. In this embodiment, as shown in FIG. 5, the width Wh of the through hole 162f of the support conductor 62 is set to be 20 times larger than the width Wb of the bent portion 64b of the bimetal 64.
[%] Is large, and Wh = 1.2 × Wb. According to this embodiment, as indicated by an arrow J in FIG. 5, the current of the main circuit is further bent from the bent portion of the bimetal 64 further leftward from the through hole 162f in the figure than in the embodiment shown in FIG. It flows to the enlarged portion 62c of the support conductor 162 through both end portions 64bc and 64bd of the support conductor 162. Therefore, the bimetal-side joint end 64c of the bimetal 64 can be more effectively formed.
Can be prevented from being concentrated. The shape of the through-hole is not limited to the through-holes 62f and 162f shown in FIGS. 3 and 5, but may be any shape as long as the object of the present invention is not impaired. For example, the shape of a track stadium or a rectangle having a sufficiently large radius of a corner to prevent current from concentrating at the corner may be used. Other configurations are the same as those of the embodiment shown in FIGS. 1 to 4, and the same components are denoted by the same reference numerals and description thereof will be omitted.
The through holes 62f and 162f in the embodiment shown in FIG. 2 or FIG. 5 may be provided at a position away from the mounting surface 62d as long as the object of the present invention is not impaired. , Including the above-mentioned adjacency, as far as the object of the present invention is not impaired, also includes a position distant from the mounting surface 62d. Embodiment 3 of the Invention FIGS. 6 to 8 show the essential parts of a thermal exfoliation device according to another embodiment of the present invention. FIG. 6 is a side view, FIG. 7 is a perspective view, and FIG.
FIG. 4 is a partially enlarged side view showing a flow of current. In these figures, reference numeral 202 denotes a plate-like material as a current concentration alleviating means and a protruding portion, and protrudes from the mounting surface 62d between the bent portion 64b of the bimetal 64 and the mounting surface 62d of the support conductor 62. It is provided. Plate material 202
Prevents current concentration at the bimetal-side junction end 64c of the bimetal 64. As shown in FIG. 6, the plate member 202 is formed by providing a notch 202a in a rectangular copper block. The plate-shaped material 202 is brazed to the mounting surface 62d such that the cutout portion 202a, which is a recessed portion, is on the side of the extending portion 62b of the support conductor 62. The bent portion 64 b of the bimetal 64 is brazed to the plate member 202. Note that, in this embodiment, the mounting surface 62d shown in FIG.
The plate member 202 is brazed. Other configurations are the same as those of the embodiment shown in FIGS. 1 to 4, and the same components are denoted by the same reference numerals and description thereof will be omitted. According to the embodiment shown in FIG. 7, the notch 202a is provided in the
The cross-sectional area on the support conductor 62 side is smaller than the cross-sectional area on the bimetal 64 side. Therefore, the current of the main circuit flows bypassing the notch 202a and is distributed as shown by the arrow K in FIG. Therefore, current does not concentrate on the bimetal-side joining end 64c, and even when a very large current flows as in the case of a short circuit, permanent deformation of the bimetal 64 can be prevented. In the embodiment shown in FIG. 7, the supporting conductors 62 are used in consideration of the yield of materials and the ease of processing.
And the plate-shaped member 202 are shown as separate members. However, as shown in the partially enlarged side view of FIG.
Plate-shaped projecting portion 2 which is a projecting portion integrally with the second support portion 62a.
The same effect can be obtained by providing the groove 12 and recessing the groove 212a, which is a concave portion, by machining from the right side of the projecting portion 212, from the extending portion 62b side of the support conductor. Embodiment 4 of the Invention In the embodiment shown in FIG. 7, current concentration is avoided by the shape of the plate-like material. However, as shown in the partially enlarged side view of FIG. 10, a spacer 222 formed of a material having higher electric resistance than the bimetal 64, for example, a copper nickel chrome alloy having a volume resistivity of 0.49 [μΩ · m] is provided. hand,
Bimetal 6 is provided on both upper and lower surfaces of the spacer 222, respectively.
4 bent portion 64b and support portion 62a of support conductor 62
Is formed by brazing. For other configurations,
Since this embodiment is the same as the embodiment shown in FIGS. 1 to 4, the same components are denoted by the same reference numerals and description thereof will be omitted. In this way, the main circuit current mainly depends on FIG.
Bimetal 64 having a small electric resistance as shown by arrow M of 0
Detours to the vicinity of the left end 64d of the bent portion 64b of the spacer 222 and the support portion 62a of the support conductor 62.
Flows to Therefore, the bent portion 64b of the bimetal 64
The current is easily diffused at the joint between the spacer and the spacer 222. Therefore, it is possible to more effectively prevent the concentration of the current flowing through the bimetal-side joint end 64c of the bimetal 64. As shown in a partially enlarged side view of FIG. 11, a notch 232a similar to the notch 202a of FIG. 7 is additionally provided on a spacer 232 formed of a material having a higher electric resistance than the bimetal 64. May be provided. By providing the cutout portion 232a, diffusion of current in the bent portion 64b of the bimetal is further promoted.
By providing the notch 232a, the spacer 23
2 Notch 2 with larger volume resistivity than bimetal
By using a material smaller than the spacers 222 without the 32a and suppressing heat generation due to a normal energizing current, the concentration of current can be effectively reduced. In each of the above embodiments, the circuit breaker having the electromagnetic trip device 50 has been described. However, the circuit breaker may have only the thermal trip device. Further, the joining between the bimetal and the supporting conductor is not limited to brazing, but may be welding, welding, welding or other metallurgical joining. Embodiment 5 of the Invention FIG. 12 and FIG.
FIG. 12 shows still another embodiment of the present invention.
FIG. 13 is a side view showing a main part of the thermal release device, and FIG. 13 is a left side view of the thermal release device. In these figures,
Reference numeral 260 denotes a thermal traction device, which is configured as follows. Reference numeral 262 denotes a support conductor, which is a plate-like support portion 262.
a and an extended portion 262b, and is formed of a copper plate having sufficient rigidity. The support portion 262a has the extension portion 2 at the center.
Having an enlarged portion 262c wider than the width of 62b;
A rectangular mounting surface 262d to be joined to a bimetal 264 described later is provided on the enlarged portion 262c so as to slightly project leftward in FIG. Reference numeral 262e denotes an upper end of the mounting surface 262d in FIG. A through hole 262f is provided near the mounting surface end 262e as a current concentration reducing means penetrating right and left in FIG. As shown in FIG. 13, the through hole 262f is long in the width direction of the support portion 262a (vertical direction in FIG. 13), and its width Wh is equal to the bimetal-side joining portion 26 of the bimetal 264.
4b is narrower than the width Wb, and has a length of 90%, and the corners are rounded. The extending portion 262b extends slightly linearly upward in FIG. 12 from the support portion 262a, and then is bent rightward to extend in an L-shape, and is connected to a shunt terminal (not shown). The extension portion 262b is provided with a screw hole 262g by burring, and is fixed to the base by a bolt (not shown). Reference numeral 264 denotes a bimetal.
4a and a bimetal-side joining portion 264b, and two metal plates having different coefficients of thermal expansion are laminated to form a flat plate as shown in the figure. The bimetal 264 is shown in FIG.
The upper part is a heat responsive part 264a, and the lower part is a bimetal-side joint part 264b. Reference numeral 264c denotes a bimetal-side joint end above the bimetal-side joint 264b. The bimetal 264 is soldered to the mounting surface 262d of the support conductor 262 by silver brazing on the right side of the bimetal side joint 264b such that the high expansion side is on the left side in FIG. Bimetal joint 264b and mounting surface 26
In the upper part in FIG. 12 of the joint portion where 2d and 2d are joined, the bimetal-side joint end 264c and the mounting surface end 262e of the support conductor face each other. Note that the backing plate 66
Is similar to that shown in FIG. In the thermal trip device 260 configured as described above, the presence of the through hole 262f also causes
As in the embodiment shown in FIG.
As shown in FIG.
b flows to the enlarged portion 262c of the support portion 262a of the support conductor 262 through both end portions 264bc and 264bd. Therefore, current does not concentrate on the bimetal-side joint end portion 264c of the bimetal 264, and even if a very large current flows like a short circuit accident, permanent deformation due to abnormal overheating of the bimetal 264 can be prevented. Further, since the through hole 262f is provided near the mounting surface end 262e, even if the brazing material flows out during the brazing, it flows into the through hole 262f. Therefore, since the protrusion does not protrude greatly from the end surface 262e of the mounting surface, the position of the fulcrum of the thermally responsive portion 264a of the bimetal 264 does not change, and stable operation characteristics can be obtained. In each of Embodiments 1 to 5, the support portions 62a and 262 of the support conductor
The same effect can be obtained even if the angle between the a and the bimetallic heat responsive portions 64a, 264a is arbitrary such as an acute angle or an obtuse angle. The circuit breaker according to the present invention is provided with a through hole provided in the extending portion so as to be near the support portion of the support conductor and penetrating the support conductor from the bimetal side to the opposite side.
Concentration of the inflow current into the bimetal has been reduced, and with a simple configuration that only requires a through-hole, the bimetal abnormally overheats due to a large current such as a short-circuit current, causing permanent deformation. And a circuit breaker having stable thermal trip characteristics can be obtained. ## EQU1 ##

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a circuit breaker according to an embodiment of the present invention. FIG. 2 is a perspective view showing details of the thermal traction device according to the embodiment of the invention shown in FIG. 1; FIG. 3 is a plan view of the thermal exfoliation device shown in FIG. 2; FIG. 4 is a side view of the thermal release device shown in FIG. 3; FIG. 5 is a plan view showing a main part of a thermal traction device according to another embodiment of the present invention. FIG. 6 is a side view showing a main part of a thermal exfoliation device according to another embodiment of the present invention. FIG. 7 is a perspective view of a main part of the thermal exfoliation device shown in FIG. 6; FIG. 8 is a partially enlarged side view of the thermal release device shown in FIG. 6; FIG. 9 is a partially enlarged side view of a thermal trip device according to another embodiment of the present invention. FIG. 10 is a partially enlarged side view of a heat release device according to another embodiment of the present invention. FIG. 11 is a partial enlarged side view of a thermal trip device according to another embodiment of the present invention. FIG. 12 is a side view showing a main part of a thermal exfoliation device according to another embodiment of the present invention. FIG. 13 is a left side view of the thermal release device shown in FIG. FIG. 14 is a perspective view showing a main part of a conventional thermal breaker for a circuit breaker. FIG. 15 is a partially enlarged side view of a conventional thermal breaker for a circuit breaker. [Description of Signs] 30a: Base, 32: Fixed contact, 34: Movable contact, 40: Opening / closing mechanism unit, 60: Thermal dynamic release device, 62
... support conductor, 62a ... support part, 62b ... extension part, 62d
... Mounting surface, 62f, 162f ... Through hole, 64 ... Bimetal, 64a ... Heat responsive part, 64b ... Bend part, 64c ...
Bimetal-side joining end portion, 202: plate-like material, 202a: cutout portion, 212: projecting portion, 212a: groove, 222, 2
32: Spacer, 260: Thermal release device, 262:
Supporting conductor, 262a ... Support portion, 262b ... Extension portion, 26
2d: mounting surface, 262f: through hole, 264: bimetal, 264a: heat responsive portion, 264b: bimetal side joint, 264c: joint end.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-39833 (JP, A) JP-A-55-115236 (JP, A) JP-A-1-100840 (JP, A) JP-A-5-115 190075 (JP, A) JP-A-8-17324 (JP, A) JP-A-63-77244 (JP, U) JP-A-5-36737 (JP, U) JP-A-62-153746 (JP, U) Japanese Utility Model Showa 62-163848 (JP, U) Japanese Utility Model Showa 61-99945 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 73/22 H01H 71/16

Claims (1)

(57) [Claim 1] A support conductor having a support portion and an extension portion extending from the support portion, the support conductor being fixed to a base, and through which a main circuit current flows, and One end is connected to the extension part so as to be able to conduct electricity, and the other end that is thermally responsively deformed by the heat generated by the main circuit current flowing through the extension part operates the opening / closing mechanism to separate the contact through which the main circuit current flows. And, in the vicinity of the support portion of the support conductor,
The support is provided in the extension section from the bimetal side to the opposite side.
A circuit breaker having a through-hole penetrating through a holding conductor to reduce concentration of the inflow current into the bimetal.