JPH0696656A - Three-pole circuit breaker - Google Patents

Abstract

PURPOSE:To provide a three-pole circuit breaker highly reliable for tripping operation and inexpensive, without any recourse to a special adjusting process, exclusive parts, or the like. CONSTITUTION:Three single-pole type circuit breakers 1, each with a case 2 housing a bimetal and having an exhaust opening section 2A for discharging arc gas, are arranged in parallel. In this case, an interlock system is provided, so that when one of the breakers 1 trips, others also concurrently trip. Regarding these single-pole type circuit breakers 1, the opening area of the section 2A is formed in such a way that the center breaker has a larger area than others.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-pole circuit breaker constructed by arranging three same one-pole type circuit breakers in parallel.

[0002]

2. Description of the Related Art The applicant of the present application has proposed a basic structure of a three-pole circuit breaker of this type in Japanese Patent Publication No. 1-33019. That is, the three-pole circuit breaker is configured by arranging three one-pole type circuit breakers 1 shown in FIG. 5 in parallel as shown in FIG.

A one-pole type circuit breaker 1 has a case 2 formed by a body (one of the case halves) 3 and a cover (the other of the case halves) 4 made of an insulating material such as plastic. Terminal devices 5A and 5B are attached to the outside of both sides, and each member constituting the circuit breaker is housed inside. Also, case 2
Has exhaust openings 2A, 2B for discharging arc gas in the vicinity of the terminal devices 5A, 5B.

[0006] 6 is a fixed contact having a fixed contact 7, 8 is a movable contact including an auxiliary plate 10 having a movable contact 9, 11 is a handle, 12 is a fixed and movable contact 7 by operating the handle,
The opening / closing mechanism section including the handle 11 for opening / closing 9 is a bimetal 17 that acts on the opening / closing mechanism section 12 to perform a trip operation when an abnormal current flows, a fixed iron piece 18 for adsorption, and a movable iron piece 19 for locking. It is an abnormal current detection means having the above.

A three-pole circuit breaker is constructed by arranging three such one-pole type circuit breakers 1 side by side as shown in FIG. 6 and connecting them by a fixture 23 such as a screw or a rivet. . 26
Is an interlocking plate that interlocks with the abnormal current detection means 16, 16, 16 of each pole,
Reference numeral 27 is a handle cap that is put on the handles 10, 10, 10 of each pole.

In this three-pole circuit breaker, when an abnormal current, for example, a short-circuit current flows, the locking movable iron piece 19 of any one of the circuit breakers 1 is attracted to the fixed iron piece 20 for adsorption, and an overcurrent flows. In this case, the bimetal 17 of one of the circuit breakers 1 is bent by Joule heat to displace the locking movable iron pieces 19, and each of them acts on the opening / closing mechanism section 12 to perform a trip operation. Link 1,1.

This three-pole circuit breaker has the same structure1
Since it can be constructed by using three pole type circuit breakers 1, the efficiency of the mold and the production line can be improved.

[0008]

The trip operation due to overcurrent of the above-mentioned three-pole circuit breaker is determined by the amount of bending of the bimetal 17, that is, the temperature rise due to the sum of the heat generation amount and the heat radiation amount. By the way, when three one-pole type circuit breakers are arranged side by side, the heat dissipation of the bimetal of the circuit breaker serving as the central pole is smaller than that of the two-sided circuit breaker, and as a result, the bimetal of the central pole is different from each other. The amount of bending increases when the same current flows through the poles. Therefore, when the rated current flows through each pole, the bimetal of the center pole may have a bending amount enough to perform the trip operation, and in order to prevent the mis-strip, only the center pole has a special adjustment process and dedicated parts. I needed to deal with.

The present invention has been made in view of the above circumstances, and its purpose is to provide a tripod with high reliability and low cost for trip operation without depending on a special adjustment process or specialization of parts. To provide a circuit breaker.

[0010]

In order to solve the above problems, a circuit breaker according to the present invention includes a fixed contact having a fixed contact, a movable contact having a movable contact, and a fixed contact by a handle operation. An opening / closing mechanism section including a handle for opening / closing the movable contact, an abnormal current detection means having a bimetal that acts on the opening / closing mechanism section to perform a trip operation when an abnormal current flows, and the above-mentioned members are housed. Three 1-pole type circuit breakers equipped with a case made of an insulating material having an exhaust opening for discharging arc gas are arranged in parallel,
In a three-pole circuit breaker in which one of the two is also interlocked with each other when it trips, a structure in which the opening area of the exhaust opening is larger for the central pole than for both sides I am trying.

Specifically, it is preferable to mount exhaust plates having exhaust holes at the exhaust openings on both sides.

Further, it is preferable that exhaust opening portions for reducing the opening area are connected to the exhaust opening portions on both sides of the pole.

[0013]

According to this structure, the circuit breaker of the central pole, which originally has a small amount of heat radiation, can have the same amount of bending as that of the both poles by increasing the amount of heat radiation from the exhaust opening.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. This three-pole circuit breaker is shown in FIG.
As shown in FIG. 1, three pole-type circuit breakers 1 are arranged side by side. In addition, the same code | symbol is attached | subjected to the member with the same basic function as the conventional thing.

Reference numeral 2 denotes a case, which is composed of a body 3 and a cover 4 which are molded from an insulating material such as plastic.
The body 3 is in the shape of a box with one surface open, and the handle opening 3b is formed in the upper wall so as to be cut out from the opening end surface. Also, the upper and lower walls and the left and right side walls of the body 3 are not of uniform thickness, and the inner wall side should be appropriately arranged in consideration of the arrangement, fixing, positioning, etc. of the member to be accommodated, and the outer wall side should be constructed in consideration of the attachment of the terminal member. design. Ie body 3 (ie case
Terminal devices 5A and 5B are attached to both sides in the longitudinal direction of 2),
Exhaust openings 2 for discharging arc gas near them
A and 2B are formed.

The cover 4 has a flat plate shape so as to close the opening of the body 3, and is fixed to the body 3 with a fixing tool such as a tapping screw or a rivet. Exhaust opening described above
Specifically, 2A and 2B are formed by fixing the cover 4 to the body 3.

Reference numeral 6 denotes a fixed contact, which is bent to have a length from the inside to the outside of the body 2 when attached to the body 3, and has a fixed contact 7 fixed to one end located on the inner side.
The other end on the external side also serves as the terminal plate of the terminal device 5A.

Reference numeral 8 denotes a movable contactor, which has a fixed contact at one lower end.
A movable contact 9 for contacting / separating with 7 is fixed, and an auxiliary plate 10 linked to an opening / closing mechanism section 12 described later is attached. Auxiliary plate 10
Is provided with a receiving portion 10a serving as a fulcrum of rotation above and a spring locking portion 10b in an intermediate portion.

Reference numeral 11 denotes a handle, which is interlocked with an opening / closing mechanism 12 which will be described later and interlocks with the movable contactor 8. The handle 11 can rotate about the lower part of the handle link 11a as a rotation fulcrum, the operation portion 11b located above protrudes from the handle opening 3b, and the spring locking portion 11c and a movable frame described later are provided in the middle portion. It has a pressing portion 11d.

Reference numeral 12 denotes an opening / closing mechanism portion including a handle 11, which opens and closes the fixed and movable contacts 7 and 9 by operating the handle 11, and performs a trip operation when an abnormal current detecting means described later is activated. The opening / closing mechanism unit 12 includes a movable frame 13 and an opening / closing spring.
14, trip spring 15, etc.

The movable frame 13 has a generally U-shape that sandwiches the movable contact 8 and has a rotation fulcrum at the same position as the rotation fulcrum of the handle 11 and is locked at one end by an abnormal current detecting means described later. A locked portion 13c, a pressing portion 13d corresponding to the pressing portion 11d of the handle 11 on the other end, a supporting portion 13e that is close to the movable contact 8 so as to press the movable contact 8 and supports one end of the trip spring.
Have. The opening / closing spring 14 is a tension spring and is a handle 11
Is tensioned between the spring engaging portion 11c of the auxiliary plate 10 and the spring engaging portion 10b of the auxiliary plate 10 to bias the auxiliary plate 10, that is, the movable contact 8 in the closing direction or the opening direction according to the position of the handle 11. . The trip spring 15 is a compression spring, is compression-suspended between the body 3 and the support portion 13e of the movable frame 13, and biases the movable frame 13 in the counterclockwise direction.

Reference numeral 16 is an abnormal current detection means, which acts on the opening / closing mechanism 12 to perform a trip operation when an abnormal current flows in the electric path. The abnormal current detection means 16 includes a bimetal 17, a fixed iron piece 18 for adsorption, a movable iron piece 19 for locking, and the like. The base end of the bimetal 17 is fixed to the end portion of the terminal plate of the terminal device 5B, the adjustment screw 17a is screwed into the tip end, and the attraction fixed iron piece 18 is held in the middle portion. The fixed iron piece 18 for adsorption is made of a magnetic plate material and is U-shaped, and may be attached to an intermediate portion of the terminal plate of the terminal device 5B.

The locking movable iron piece 19 is made of a magnetic plate and has a substantially T-shape in a side view. That is, the intermediate portion 19a has the shaft 20
Is rotatably supported on the movable frame 13 and a locking portion 19c for locking the locked portion 13c of the movable frame 13 is formed.
Faces the adjusting screw 17a of the bimetal 17 and the other end 19e
Faces the fixed iron piece 18 for adsorption. Reference numeral 21 is a return spring for biasing the locking movable iron piece 19 in the clockwise direction by the bimetal.

In the abnormal current detecting means 16, when an overcurrent flows through the bimetal 17 and it is deformed, the locking movable iron piece 19 also moves accordingly, and a short-circuit current flows through the bimetal 17 to the adsorption fixed iron piece 18. When a large magnetic flux flows, the locking movable iron piece 19 is immediately attracted to the end surface of the adsorption fixed iron piece 18 and moves. That is, when an abnormal current such as an overcurrent or a short-circuit current flows in the electric circuit, the movable frame 13 is operated to perform the trip operation.
The locked portion 13c is released from the locking portion 19c of the locking movable iron piece 19. 22 is a braided wire that connects the bimetal 14 and the movable contact 8.

The three-pole circuit breaker has three such one-pole type circuit breakers 1 arranged side by side as shown in FIG. 1, and is fixed by screws or rivets like the conventional one. Although they are connected to each other, the structure of the exhaust openings 2A, 2A, 2A is different between the two side poles and the central pole. That is, as shown in FIG. 3, exhaust plates 24, 24 having a plurality of exhaust holes 24a, 24a, are attached to the exhaust openings 2A, 2A of both poles, and the exhaust openings 2A of the central pole are attached. The above-mentioned exhaust plate 24 is not attached to this, so that the opening area of the exhaust openings 2A, 2A, 2A is made larger for the central pole than for the both poles. Although omitted in FIG. 1, there is an interlocking plate interlocking with the abnormal current detecting means 16, 16, 16 of each pole, as in the conventional one.

In this three-pole circuit breaker, when an abnormal current, for example, a short-circuit current flows, the locking movable iron piece 19 of any one of the circuit breakers 1 is attracted to the adsorption fixed iron piece 18 and an overcurrent flows. In this case, the bimetal 17 of one of the circuit breakers 1 is bent by Joule heat to displace the locking movable iron pieces 19, and each of them acts on the opening / closing mechanism section 12 to perform a trip operation. Link 1,1.

In this case, the amount of bending of the bimetal 17, especially when an overcurrent flows, is determined by the temperature rise due to the sum of the amount of heat generation and the amount of heat dissipation, and the heat dissipation of the bimetal 17 of the circuit breaker 1, which is essentially the central pole, is on both sides. Although the amount of heat radiation is smaller than that of the pole, in the case of this embodiment, the circuit breaker 1 of the central pole increases the amount of heat radiation from the exhaust opening 2A, so that the bimetal 17 becomes A similar amount of curvature can be used.

Next, another embodiment of the present invention will be described with reference to FIG. This is different from the previous embodiment only in the structure of the exhaust openings 2A, 2A, 2A of the circuit breakers 1, 1, 1.

That is, the body forming the exhaust opening 2A
3) Exhaust block part that covers about half of the opening area in advance
25 is integrally formed. The exhaust blocking portion 25 has a thin portion particularly at its root portion so that it can be torn off later. Then, the one serving as the both poles is in a state where the exhaust blocking portion 25 exists, and the one serving as the central pole tears off the exhaust blocking portion 25, whereby the opening area of the exhaust openings 2A, 2A, 2A is changed to the central pole. The ones are bigger than those on both sides. Also in this case, similarly to the previous embodiment, the bimetal 17 of the central pole can have the same amount of curvature as that of the both poles, and does not require a separate member such as an exhaust plate.

[0030]

In the three-pole circuit breaker of the present invention, the circuit breaker of the central pole, which originally has a small heat radiation amount, can have the same bending amount as the two-sided poles by increasing the heat radiation amount from the exhaust opening. Therefore, the trip operation is highly reliable and can be made inexpensive, without depending on a special adjustment process or specialization of parts. In particular, the number of components can be further reduced by connecting the exhaust openings of the both poles to the exhaust blocking section for reducing the opening area.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a side view excluding a cover of a circuit breaker that constitutes one pole thereof.

FIG. 3 is a perspective view of the exhaust plate.

FIG. 4 is a side view of the circuit breaker according to another embodiment of the present invention with the cover removed.

FIG. 5 is a side view of a conventional circuit breaker excluding a cover of a circuit breaker constituting one pole.

FIG. 6 is an exploded perspective view of the whole thereof.

[Explanation of symbols]

 1 1-pole type circuit breaker 2 Case 2A, 2A Case exhaust opening 3 Body that forms the case 4 Cover that forms the case 5A, 5B Terminal device 6 Fixed contact 7 Fixed contact 8 Movable contact 9 Moving contact 10 Auxiliary plate 11 Handle 12 Opening / closing mechanism 13 Movable frame 14 Opening / closing spring 15 Trip spring 16 Abnormal current detection means 17 Bimetal 18 Fixed iron piece for adsorption 19 Movable iron piece for locking 24 Exhaust plate 25 Exhaust block

Claims (3)

[Claims] 1. A fixed contact having a fixed contact, a movable contact having a movable contact, an opening / closing mechanism section including a handle for opening and closing the fixed and movable contacts by operating a handle, and an abnormal current flowed. An abnormal current detection means having a bimetal that acts on the opening / closing mechanism to perform a trip operation at times, and a case made of an insulating material that accommodates each member and has an exhaust opening for discharging arc gas are provided. In the three-pole circuit breaker, in which three one-pole type circuit breakers are installed side by side so that when one of the circuit breakers trips, the others also interlock, the opening area of the exhaust opening The three-pole circuit breaker is characterized in that the one with the central pole is made larger than the one with the two poles. 2. The three-pole circuit breaker according to claim 1, wherein exhaust plates having exhaust holes are attached to the exhaust openings of the both poles. 3. The three-pole circuit breaker according to claim 1, wherein exhaust opening portions for reducing the opening area are connected to the exhaust opening portions of the both poles.