KR20140065010A - Circuit breaker - Google Patents

Abstract

Provided is a circuit breaker capable of realizing a stable operation without changing the tripping time before and after the interruption without largely changing the conventional external form and structure.
The thermal tripping device 50 includes a bimetal upper base 52 fixed to the front end of the bimetal 51 and a bimetal upper base 52 which is rotatably provided on the bimetal upper base, A bimetal upper spring 54 which is held on the bimetallic upper base and presses the bimetallic upper with a load equal to or greater than the tripping load of the breaker 20 at all times, The bimetal upper spring is rotated against the bimetal upper spring by bending the bimetal during the overcurrent of the converter to drive the trip bar through the overcurrent characteristic adjusting member.

Description

Circuit breaker {CIRCUIT BREAKER}

The present invention relates to a thermal tripping device for tripping an opening and closing device by driving a trip bar by a bimetal that curves at the time of overcurrent of an electric path, tripping device.

In a circuit breaker corresponding to a converter including a conventional harmonic component, a thermal tripping device is employed. This thermal tripping device is generally configured to trip a trip bar by driving a trip bar by a bimetal which is curvedly deformed at the time of an overcurrent of a converter.

This circuit breaker should be connected to the bimetal directly (for example, less than 30A), which should meet the requirement of less than 2 minutes operation specified in the Electrical Appliance and Material Safety Law, Energization), thereby satisfying the operation within 2 minutes (see, for example, Patent Document 1).

However, when the short-circuit current at the time of short-circuit passes through the bimetal, the bimetal causes melting or the bimetal causes permanent deformation.

To prevent this, a circuit breaker is known in which an extension plate is disposed at the tip of a bimetal (see, for example, Patent Document 2).

[Patent Document 1] Japanese Patent Application Laid-Open No. 2008-153072 [Patent Document 2] JP-A-2010-218765

In the conventional circuit breaker configured as described above, when increasing the breaking capacity, the increase in the passing current at the time of breaking greatly affects the tripping operation time delay after the breaking due to the permanent deformation of the bimetal.

The reason for this is that since the stopper bar connecting the opening / closing device and the thermal tripping device is tripped, the bimetal at the time of interruption is restrained by the position of the stopper, Causing deformation.

Therefore, after the cutoff, the distance between the trip bar and the bimetal increases due to this permanent deformation, leading to a delay of the tripping operation time.

In order to increase the arc length on the side of the arc extinguishing device, it is necessary to enlarge the outer shape, to enlarge the contact opening distance, to open the contact openings, Such as reducing the starting time and opening time or improving the current limiting performance such as narrowing the arc diameter due to a rise in the pressure up or adopting a tripping device that does not allow the bimetal to pass when a large current is cut off , It is difficult to keep the external dimensions of the development and to achieve miniaturization. Needless to say, it is disadvantageous in cost.

In addition, in the configuration in which the extension plate is arranged as in Patent Document 2, in order to satisfy the stable heat-drifting property at the initial stage, the warpage of the extension plate due to the tripping load should be generally suppressed to 0.5 mm or less.

For this reason, in order to generate the load of the tripping load at the extension of 0.5 mm, the spring constant should be set to a considerably high plate material.

As a result, a plate having the same stiffness as the bimetal is required in this extension plate, and the bending moment of the bimetal is transmitted to the bimetal as it is at the time of interruption, making it difficult to prevent permanent deformation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a circuit breaker having a thermal tripping device capable of realizing a stable operation without changing the tripping time before and after the interruption without largely changing the external shape and structure.

The present invention relates to an electronic tripping device for operating an open / close contact for opening and closing a converter, an electronic tripping device for tripping the tripping bar by driving a tripping bar when an excessive current flows through the turnover, Wherein the thermal tripping device includes a bimetal upper base fixed to a front end of the bimetal, and a bimetal upper base fixed to a front end of the bimetal, A bimetal upper which is rotatably provided on the base and is fixed to an overcurrent characteristic adjusting member opposed to the trip bar with a predetermined gap therebetween; a bimetallic member held by the bimetallic upper base, And a bimetallic upper spring for pressing the load with a load equal to or greater than the load, The bimetallic upper is rotated against the bimetal upper spring by bending of the bimetal during an overcurrent of the converter, and the trip bar is driven through the overcurrent characteristic adjusting member.

The present invention can realize a heat-operated tripping device capable of stable operation without changing the tripping time before and after the interruption with a minimum number of additional parts without largely changing the conventional external form and structure, A circuit breaker of a breaking capacity can be easily obtained.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an entire vertical sectional view showing a circuit breaker according to Embodiment 1 of the present invention. FIG.
2 is an enlarged side view showing the tripping device in Fig.
3 is an enlarged perspective view showing a main part of the thermal tripping device in Fig.
4 is an entire longitudinal sectional view showing a circuit breaker in shutdown in the first embodiment.
5 is an enlarged side view showing the tripping device in Fig.
6 is an enlarged side view showing a bending state of the bimetal in the thermal tripping device of FIG.
Fig. 7 is an explanatory diagram showing the load characteristics of the bimetallic upper of the heat-tripping apparatus in the first embodiment compared with that of the conventional structure. Fig.
8 is an enlarged perspective view showing the main part of the heat-tripping apparatus in Embodiment 2 of the present invention.
9 is an enlarged side view showing the tripping device at the maximum trip position in the second embodiment.

Embodiment 1

First, the schematic structure of the circuit breaker according to the first embodiment of the present invention will be described with reference to the drawings.

1, a circuit breaker 100 is constructed using a case 1 comprising a base 2 and a cover 3 formed of an insulating material.

On the base 2, circuit breaker units (for example, three in the case of three phases) are arranged in parallel with each other by the number of poles, and a well-known toggle link is provided on the upper portion of the circuit breaker unit. A switch mechanism 20 having a mechanism is disposed.

The cover 3 covers the circuit breaker unit and the breaker unit 20 of each phase on the base 2 and the operation handle 21 of the breaker unit 20 protrudes from the cover 3.

The circuit breaker units of each phase have the same configuration, and the crossbar 10 is disposed on the base 2 so as to cross the circuit breaker units of each phase and perpendicularly to the circuit breaker units of each phase.

The circuit breaker unit of each phase includes a power source side terminal 7 provided on the base 2, a fixed contact 4 extending from the power source side terminal 7, a movable contact 5 which is brought into contact with the fixed contact 4, A movable contact 6 which is provided at one end of the movable contact 5 and is rotatably held by the cross bar 10 and a trip contact 6 which is connected to the movable contact 6 via the mover holder 9, And a load side terminal 8 connected to the tripping device 30 and provided on the base 2. The load side terminal 8 is connected to the tipping device 30, The stationary contact 4 and the movable contact 5 form an open / close contact for opening and closing the converter.

The electric circuit between the power source side terminal 7 and the load side terminal 8 is turned ON when the movable contact 5 contacts the fixed contact 4 and the movable contact 5 is fixed The electric circuit between the power source side terminal 7 and the load side terminal 8 is turned off.

The crossbar 10 is disposed at the bottom of the base 2 and extends perpendicular to the plane of Fig. The crossbar 10 is pivoted about the central axis thereof by the switchgear portion 20, and the respective movable contacts 6 of the respective circuit-breaker units are mounted.

The movable contacts 6 of the circuit breaker units of the respective phases are rotated at the same time when the crossbar 10 is rotated around the axis thereof and the movable contacts 5 are fixed And contacts the contact point 4.

The switch 20 is composed of a well-known toggle link mechanism and includes a known trip bar 22 driven by the tripping device 30 and a trip switch 22 for tripping the trip bar 22 at the maximum trip position And a bar stopper 23.

The arc furnace 11 is disposed close to the movable contact 6 so that the arc generated between the movable contact 5 and the stationary contact 4 during the operation of the opening and closing device 20 is extinguished.

The tripping device 30 is composed of an electromagnetic (electromagnetic) tripping device 40 and a thermal tripping device 50 as shown in FIG.

The electromagnetic tripping device 40 includes a stationary iron core 41 and a movable iron core 42 which is attracted to the stationary iron core 41 at instantaneous interruption and drives the trip bar 22, And a shaft 44 for pivotally supporting the movable iron core 42. The return spring 43 is provided with a return spring 43,

3 (a) and 3 (b) are enlarged perspective views of the main parts of the heat-tripping device 50 as viewed from opposite directions. The thermal tripping device 50 includes a bimetal 51 fixedly connected to the mover holder 9 at the lower end thereof, a bimetallic upper base 52 fixed to the front end of the bimetal 51, A bimetal upper part 54 which is pivotally supported on the rotary shaft 53 with a rotary shaft 53 as a rotary shaft and is screwed with an overcurrent characteristic adjusting screw 57, And a bimetal upper spring 56 for pressing the upper 54 in the direction of the trip bar 22.

The bimetallic upper 54 is always pressed by the bimetallic upper spring 56 while abutting against the bimetallic upper stopper 55 provided on the bimetallic upper base 52. The spring load on the bimetallic upper 54 is the same as the trip Is set to be larger than the tripping load at the abutting position of the bar (22)

A tubular connecting member (58) is fixed to the upper end of the bimetal (51) by a rivet (60). The bimetal 51 is connected to the load side terminal 8 through the tubular connecting member 58 and the flexible conductor 59 so that the current of the converter flows.

3 shows an example in which the bimetallic upper base 52 is integrally formed with the through-hole connecting member 58. However, the bimetallic upper base 52 and the through-hole connecting member 58 may be provided separately, Both of them may be fixed by welding or the like.

Next, the breaking operation of the circuit breaker 100 will be described.

When an overcurrent more than a predetermined current flows through the bimetal 51, the bimetal 51 itself generates heat, and the bimetal 51 is curved and deformed by this heat.

When the bimetal 51 is curved, the overcurrent adjusting screw 57 is fixed to the bimetal 51 through the bimetal upper 54 and the bimetal upper base 52. Thus, 22, the switch 20 is driven to rotate the movable contact 6. The movable contact 5 is opened from the stationary contact 4 by the rotation of the movable contactor 6 and the operation of current interruption is completed (see Figs. 4 to 6)

4 is a state in which the thermal tripping device 50 is operated. In this state, the movable contact 5 is still in contact with the stationary contact 4.

The bimetallic upper 54 is brought into contact with the bimetallic upper stopper 55 provided on the bimetallic upper base 52 and the bimetallic upper stopper 55 provided on the bimetal upper stopper 55 when the overcurrent adjusting screw 57 presses the trip bar 22. [ Is always urged in the direction of the trip bar (22).

In this case, since the spring load of the bimetallic upper 54 is set to be larger than the tripping load at the abutting position of the trip bar 22, the bimetallic upper 54 pushes the trip bar 22 .

7 shows the load characteristic of the bimetallic upper 54 of the thermal tripping device 50 compared with that of the conventional structure. The spring load at the bimetallic upper end 54 is the abutment position of the trip bar 22 Is set to be larger than the tripping load and at the lock position of the trip bar 22 is set to be smaller than the spring load of the extension plate of the conventional structure.

The bimetallic upper 54 can push the trip bar 22 without pivoting and the trip bar 22 is driven so that the opening and closing device 20 In the tripped state, the bimetallic upper spring 56 is bent in accordance with the load applied to the bimetallic upper 54.

When an excessive current such as a short-circuit current flows, the movable iron core 42 is attracted to the fixed iron core 41 by the magnetic force generated in the fixed iron core 41 of the electromagnetic tripping device 40, (42) rotates against the urging force of the return spring (43) with the shaft (44) as a rotating shaft.

By this rotation, the movable core 42 presses the trip bar 22 and the switch 20 is driven to rotate the movable contact 6.

By the rotation of the movable contactor 6, the movable contact 5 is opened from the fixed contact 4, and the excessive current is interrupted to complete the trip operation.

However, the bimetal 51 is bent even when an excessive current such as a short-circuit current flows, and the curved stroke becomes equal to or greater than the stroke at which the trip bar 22 abuts against the trip bar stopper 23 of the switch 20.

For this reason, the bimetallic upper 54 rotates. The bimetallic upper spring 56 flexes and the bimetallic upper 54 rotates because a load equal to or greater than the spring load characteristic of the bimetal upper spring 56 is applied to the bimetallic upper 54.

By the rotation of the bimetallic upper plate 54, the bimetal 51 is not subjected to a load greater than the spring load characteristic of the bimetal upper spring 56.

The curved stroke of the bimetal 51 is forcibly fixed by the trip bar stopper 23 and is permanently deformed by the trip bar stopper 23 of the opening and closing device 20 according to the related art. However, according to the present embodiment, The bimetal upper spring 56 is bent and the bimetallic upper 54 is rotated when the load applied to the bimetal 51 is greater than the spring load characteristic of the bimetal upper spring 56, .

This makes it possible to obtain a circuit breaker capable of stable tripping without a change in tripping time before and after the cutoff.

Embodiment 2 Fig.

8 (a) and 8 (b) are enlarged perspective views showing the main parts of the thermal tripping device 50 as viewed from opposite directions, and Fig. 9 is an enlarged side view showing a tripping device at the maximum trip position in the second embodiment.

In the second embodiment, the bimetallic upper spring 56 constituted by a torsion spring in the first embodiment is replaced with a bimetallic upper spring 61 composed of a compression spring. Other configurations are the same as those of the first embodiment, and a description thereof will be omitted.

In the second embodiment, the bimetallic upper spring is a compression spring, but it may be constituted by a tension spring or the like, and the same effect can be obtained.

Further, the present invention can freely combine the embodiments, or appropriately modify, or omit the embodiments within the scope of the invention.

100 circuit breaker 1 frame
2 base 3 cover
4 Fixed contact 5 Movable contact
6 Movable contactor mover 7 Power side terminal
8 Load side terminal 9 Mover holder
10 Crossbows 11 SOHO
20 Breaker switch 21 Operation handle
22 Trip Bar 23 Trip Bar Stopper
30 tripping device 40 Electronic tripping device
41 fixed iron core 42 movable iron core
43 Return spring 44 Shaft
50 Thermal tripping device 51 Bimetal
52 Bimetallic upper base 53 Rotary shaft
54 Bimetallic Upper 55 Bimetallic Upper Stopper
56 Bimetallic upper spring 57 Overcurrent adjustment screw
58 communication exclusive connection member 59 flexible conductor
60 rivet 61 Bimetallic upper spring

Claims (3)

An electronic tripping device for tripping the opening / closing device by driving a trip bar when an excessive current flows in the electric circuit; A circuit breaker having a thermal tripping device for driving the trip bar by means of a bimetal that curves at the time of an overcurrent of the converter to trip the breaker,
The thermal tripping apparatus comprises:
A bimetal upper base fixed to the tip of the bimetal,
A bimetal upper which is rotatably provided on the bimetallic upper base and is fixed to an overcurrent characteristic adjusting member facing the trip bar with a predetermined gap therebetween,
And a bimetallic upper spring which is held by the bimetallic upper base and presses the bimetallic upper always with a load greater than a tripping load of the bimetal upper portion,
Wherein the bimetal upper is rotated against the bimetal upper spring by bending of the bimetal during the overcurrent of the converter to drive the trip bar through the overcurrent characteristic adjusting member. The method according to claim 1,
And the bipolar upper spring is bent in accordance with a load applied to the bimetallic upper part in a state in which the trip bar is driven and the opening / closing mechanism part is tripped. The method according to claim 1 or 2,
Wherein the bimetallic upper spring is a torsion spring, a compression spring, or a tension spring.

Images