JPH0729478A - Circuit breaker - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the installation space of an overcurrent trip device in a circuit breaker equipped with both electronic and electromagnetic overcurrent trip devices. [Structure] The fixed iron core 16 of the electromagnetic overcurrent trip device is also used as the core retainer of the current transformer 5 of the electronic overcurrent trip device.
Slide the movable iron piece 17 onto the current transformer 5 so that it can slide freely
Support with 1. As a result, the electromagnetic overcurrent trip device is integrated with the current transformer 5, the required space is reduced, and the circuit breaker is downsized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker such as a circuit breaker for the purpose of protecting an electric wire, and more particularly to an improvement of a device for detecting an overcurrent state of an energizing current and operating a trip mechanism. .

[0002]

2. Description of the Related Art There are several types of overcurrent trip devices installed in the above circuit breaker, such as an electronic type and an electromagnetic type. The electronic type detects the energizing current as a current signal by a current transformer, and when it judges that it is in an overcurrent state, it drives the trip coil to operate the tripping mechanism, and it is easy to adjust the rated current and tripping characteristics. There are advantages such as being. On the other hand, the electromagnetic type is one in which the movable iron piece is attracted to the fixed iron core to operate the tripping mechanism in an overcurrent state. This electromagnetic system may be installed for backup or for instantaneous characteristics.

FIG. 4 is a vertical sectional view showing such a conventional circuit breaker. In the figure, the energizing current is fixed to the left end of the figure by a fixed contactor 1 integrally formed with a power supply side terminal, a movable contactor 2 which is brought into contact with and separated from the fixed contactor 3, a fixed conductor 3 which is brought into sliding contact with the fixed contactor 3, and a screw which is tightened by a screw. It flows in the path of the main conductor 4 which serves as a conduction path of the electromagnetic overcurrent trip device, and the through conductor 6 which is joined to the main conductor 4 and penetrates the current transformer 5 of the electronic overcurrent trip device. The right end of the through conductor 6 in the drawing is a load side terminal. As shown in FIG. 5, the current transformer 5 has a structure in which a secondary coil 8 is separately wound in two upper and lower parts around a core 7 in which silicon steel plates are laminated in a square shape. It is fastened by a rivet 10 via a presser 9. The penetrating conductor 6 penetrates the hollow portion of the core 7.

Referring again to FIG. 4, the current transformer 5 detects the current flowing through the through conductor 6 as a current signal, and the printed board 1
1 to the electronic circuit above. The electronic circuit constantly monitors the magnitude of this current signal, and if it judges that it is an overcurrent, it waits for the delay time corresponding to the magnitude of the overcurrent to output a trip signal, and shows only the outline with a chain line. The trip coil 12a in the trip coil unit 12 is driven. Although a detailed structure is omitted, when the trip coil 12a receives a trip signal, a movable iron core (not shown) is actuated to slide the trip bar 12b to the left in the figure, and a part of the trip mechanism 13 is pulled by a hook at its tip. The trip crossbar 14 is rotated counterclockwise in the figure. As a result, the movable contact 2 is opened by the opening / closing mechanism 15 which is unlocked.

On the other hand, a U-shaped fixed iron core 16 of an electromagnetic overcurrent trip device is attached to the main conductor 4 so as to surround the main conductor 4, and a movable iron piece 17 is opposed to the fixed iron core 16.
It is rotatably supported by the main body case 18 via 7a. The movable iron piece 17 is held in the illustrated posture in which the armature pole portion 17b at one end is separated from the fixed iron core 16 by the return spring 19 formed of a tension spring provided between the movable iron piece 17 and the operation portion 17c at the other end. It is close to the crossbar 14. This electromagnetic overcurrent trip device is provided as a backup for the instantaneous characteristics of the electronic overcurrent trip device. When a large current such as a short-circuit current flows through the main conductor 4, the movable iron piece 17 causes the movable iron piece 17 to have a contact portion 17b. Is attracted to the fixed iron core 16 and rotates counterclockwise around the support shaft 17a as a fulcrum, and the trip crossbar 14 is hit by the operating portion 17c to rotate it in the counterclockwise direction. As a result, even if the electronic overcurrent trip device does not operate normally, the movable contactor 2 is opened.

[0006]

In such a conventional circuit breaker, as shown in FIG. 4, the current transformer 5 of the electronic overcurrent trip device and the fixed core 1 of the electromagnetic overcurrent trip device are provided.
6 and the movable iron piece 17 are separately arranged along the longitudinal direction of the circuit breaker. Therefore, conventional circuit breakers with both electronic and electromagnetic overcurrent trip devices require a large space for the installation of these overcurrent trip devices, resulting in a large longitudinal dimension. It was SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a circuit breaker in which the space required for installing both electronic and electromagnetic overcurrent trip devices is reduced and downsized.

[0007]

In order to achieve the above object, the present invention holds a movable iron piece and a fixed iron core of an electromagnetic overcurrent trip device in a current transformer of an electronic overcurrent trip device. I shall. In that case, if the fixed iron core of the electromagnetic overcurrent trip device is also used as the core retainer of the current transformer, the structure becomes simple.

[0008]

[Operation] Both of the overcurrent trip devices are integrated by using the current transformer of the electronic overcurrent trip device to hold the movable iron piece and the fixed core of the electromagnetic overcurrent trip device. The required space is reduced. In that case, if the fixed iron core of the electromagnetic overcurrent trip device is also used as the core retainer of the current transformer, the number of parts is reduced and the structure is simplified.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. Here, FIG. 1 is a longitudinal sectional view of a main part of the circuit breaker, FIG. 2 is a perspective view of the current transformer portion of FIG. 1, and FIG. 3 is an exploded perspective view of the current transformer portion of FIG. The same reference numerals are used for the parts corresponding to those of the conventional example. First, in FIGS. 2 and 3, the core retainer on the front side of the current transformer 5 in the drawings has its upper end bent at a right angle in an inverted L shape, and is configured as a pair of left and right fixed iron cores 16. The fixed iron core 16 is made of an iron plate, and the L curved portion 16a thereof is an armature portion. This fixed core 16 is provided with the core retainer 9 on the opposite side and the hole 7a of the core 7.
It is conventionally clamped by rivets 10 passing through (FIG. 3).

On the other hand, the movable iron piece 17, which is also made of an iron plate, is formed in a gate shape extending over both the left and right sides of the core 7, and the tips of both legs are bent at right angles into an L shape as the contact pole portions 17a. The movable iron piece 17 is provided with elongated holes 20 in both legs, and the movable iron piece 17 passes through the elongated hole 20 and the hole 7b of the core 7 is formed.
3 is supported by a guide pin 21 with a head press-fitted in FIG. 3 so as to be slidable up and down in the figure, and the armature portion 17a faces the armature portion 16a of the fixed iron core 16. The current transformer 5 supporting the fixed iron core 16 and the movable iron piece 17 is housed in the main body case 18 as shown in FIG. 1. In the illustrated embodiment, the main body case 18 having the same size as that of the conventional example is used. Compared with FIG. 4 of the related art, the current transformer 5 is installed in a place where the conventional electromagnetic type overcurrent trip device is provided, and the main conductor 4 is omitted and the extended through conductor 6 is directly connected to the fixed conductor 3. Has been done.

The movable iron piece 17 is suspended by a return spring 19 which is a tension spring provided between the movable iron piece 17 and a printed board case 22 supported by being fitted into the main body case 18 and is placed in a posture shown in the drawing away from the fixed iron core 16. Is held. A trip lever 23, which is a resin molded product, is provided between the movable iron piece 17 and the trip crossbar 14. As shown in FIG. 3, the trip lever 23 has a shape in which an operating piece 23b extending forward and backward and a passive piece 23c are integrally formed in a hook shape on a rotary shaft 23a having small diameters at both ends. It is rotatably supported by the main body case 18 via the small diameter portion. Then, as shown in FIG. 1, the operation piece 23b is closely opposed to the trip crossbar 14, and the passive piece 23c is in contact with the lower surface of the body portion of the movable iron piece 17.
The trip lever 23 is biased counterclockwise in FIG. 1 by a torsion spring (not shown) provided between the trip lever 23 and the main body case 18.

In such a structure, when a large current such as a short-circuit current flows through the through conductor 6, the operation of the electronic overcurrent trip device by the secondary output of the current transformer 5 is the same as that of the conventional one. The movable iron piece 17 is attracted to the fixed iron core 16.
The movable iron piece 17 rotates the trip lever 23 clockwise through the passive piece 23c in FIG. 1, and accordingly the trip lever 23 rotates the trip crossbar 14 counterclockwise through the operation piece 23b. Let As a result, the instantaneous trip is executed even when the electronic overcurrent trip device is inoperative.

According to the above-mentioned structure, since the electromagnetic overcurrent trip device is integrated with the current transformer 5, the required space is almost the same as in the case of only the electronic overcurrent trip device.
As shown in the figure, when the main body case 18 having the same size as the conventional one is used, there is a space 24. Therefore, if a zero-phase current transformer for earth leakage detection is installed in this portion, a circuit breaker with an earth leakage detection function can be constructed with the same longitudinal dimension as the conventional one. Only the longitudinal dimension of the circuit breaker can be reduced. Further, in the illustrated embodiment, since the fixed iron core 16 is also used as one core pressing member, the number of parts is reduced and the structure is simplified.

[0014]

According to the present invention, the overcurrent trip device is installed by holding the movable iron piece and the fixed iron core of the electromagnetic overcurrent trip device in the current transformer of the electronic overcurrent trip device. The space can be reduced, and the circuit breaker can be downsized accordingly, and the same external dimensions as the conventional one can be provided with the leakage detection function. Further, in this case, if the fixed iron core of the electromagnetic overcurrent trip device is also used as the core retainer of the current transformer, the number of parts is reduced and the structure is simplified.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part of a circuit breaker according to an embodiment of the present invention.

FIG. 2 is a perspective view of a current transformer portion in FIG.

FIG. 3 is an exploded perspective view of the current transformer portion of FIG.

FIG. 4 is a vertical sectional view of a conventional circuit breaker.

5 is a perspective view of the current transformer in FIG. 4. FIG.

[Explanation of symbols]

 5 Current Transformer 6 Through Conductor 7 Core 8 Secondary Coil 9 Core Presser 12a Trip Coil 13 Tripping Mechanism 15 Opening / Closing Mechanism 16 Fixed Iron Core 17 Movable Iron Piece 18 Body Case 19 Return Spring 20 Long Hole 21 Guide Pin 23 Trip Lever

Claims (2)

[Claims] 1. A current transformer detects an overcurrent state of an energized current,
Electronic overcurrent trip device that drives the trip coil to operate the trip mechanism, and electromagnetic overcurrent trip device that operates the trip mechanism by attracting the movable iron piece to the fixed iron core in the overcurrent state of the energizing current. And a movable iron piece of the electromagnetic overcurrent trip device and a fixed iron core held by a current transformer of the electronic overcurrent trip device. 2. The circuit breaker according to claim 1, wherein the fixed iron core of the electromagnetic overcurrent trip device is also used as the core retainer of the current transformer.