WO2003071566A1

WO2003071566A1 - Air circuit breaker

Info

Publication number: WO2003071566A1
Application number: PCT/JP2002/001623
Authority: WO
Inventors: Hiroshi Okashita; Junichi Kawakami
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2002-02-22
Filing date: 2002-02-22
Publication date: 2003-08-28
Also published as: JPWO2003071566A1; TW556240B; JP4030504B2; ES2342047T3; CN1215511C; KR20030086582A; KR100496596B1; DE60236214D1; EP1492138A1; CN1493084A; EP1492138A4; EP1492138B1

Abstract

An air circuit breaker is made inexpensive by dispensing with an alloy contact in an arc contactor provided on an extinction device side separately from an on/off contact. A first resistor (31) is interposed between a fixed conductor (2) and a fixed side arc contactor (4a), and a second resistor (32) between a moving element (7) and a moving side arc contactor (8a). When the moving element is on, the moving side arc contactor (8a) is abutted with the fixed side arc contactor (4a) to bring the moving contact (6) into contact with a fixed contact (3), and then to separate the moving side arc contactor (8a) from the fixed side arc contactor (4a). When the moving element is off, the moving side arc contactor (8a) is brought into contact with the fixed side arc contactor (4a) to separate the moving contact (6) from the fixed contact (3), and then to open and close the moving side arc contactor (8a) and the fixed side arc contactor (4a) by swinging. Thus, a current carried by both the contactors when opened and closed is restricted by the first resistor (31) and the second resistor (32).

Description

Description Air Circuit Breaker-Technical Field

The present invention relates to an improvement in a switching contact of an air circuit breaker. Background art

FIG. 4 is a side sectional view of a conventional air circuit breaker described in, for example, Japanese Patent Application Laid-Open No. 2-904424.

In the figure, 1 is a housing formed of an insulating material, 2 is a fixed conductor arranged in parallel with several poles on the housing 1, a fixed contact 3 is fixed at one end, and the other end is outside the back of the housing 1. To form the power supply side terminal 2a. Reference numeral 4 denotes a fixed-side arc conductor extending from the fixed conductor 2 in the direction of the arc extinguishing device described later, and reference numeral 5 denotes a fixed-side arc contact fixed to the tip of the fixed-side arc conductor 4.

Reference numeral 6 denotes a movable contact opposed to and separated from the fixed contact 3, reference numeral 7 denotes a movable element having the movable contact 6 fixed thereto, reference numeral 8 denotes a movable arc conductor obtained by extending the movable element 7 toward the arc extinguishing device, and reference numeral 9 denotes a movable arc conductor. Denotes a movable arc contact fixed to the tip of the movable arc conductor 8.

Reference numeral 10 denotes a contact arm that rotatably holds the mover 7, 11 denotes a contact arm; and a contact arm shaft that supports L 0 on the housing 1. Reference numeral 12 denotes a terminal conductor, which is fixed to the housing 1 and led out to the outside of the housing 1 to form the power supply terminal 12. A flexible conductor 13 movably connects the mover 7 to the terminal conductor 12. 14 is a contact pressure spring that urges the mover 7 in the opening direction, 15 is an opening / closing mechanism, 16 is the axis of rotation of the mover 7, 17 is an arc extinguishing device, and 18 is a trip This is the Leh club. 'The opening / closing mechanism 15 is composed of a well-known todar link mechanism, and opens / closes the mover 7 to turn on / off the air circuit breaker. In the ON state, the latch is locked by a latch (not shown) that engages with the trip relay section 18 to maintain the ON state. It turns off when the latch is disengaged. Reference numeral 19 denotes a closing panel on which the closing drive force of the opening / closing mechanism 15 is stored, and 20 denotes a cam mechanism for compressing and storing the closing spring 19 by the handle 21 or a motor (not shown).

Such an air circuit breaker detects an overcurrent or an excessive current due to an accident or the like in the connected load, and trips the relay 18 to release the latch and activates the switching mechanism 15 Then, the contact arm 10 is pushed up around the contact arm shaft 11 by the force of the contact pressure panel 14, and the mover 7 is rotated counterclockwise around the shaft 16, The fixed contact 3 and the movable contact 6 are separated to cut off the current between both contacts.

The mover 7 connected to the opening / closing mechanism 15 is on. ■ The contact arm 10, the axis 16, and the contact arm axis 11 are in a positional relationship so as to swing when off. The swing operation of the mover 7 will be described.

In the ON state, the movable contact 6 and the fixed contact 3 are in contact with each other, but the movable arc contact 9 and the fixed arc contact 5 are separated. At the time of the breaking operation, the movable contact 6 is slightly separated from the fixed contact 3 as the contact arm 10 of the opening / closing mechanism 15 is pulled up, and electric current is applied between the two contacts by an arc. The mover 7 is rotated clockwise about the shaft 16 by the pressing force of the contact pressure panel 14, and the movable-side arc contact 9 contacts the fixed-side arc contact 5. The movable contact 6 and the fixed contact 3 are large with the movable arc contact 9 and the fixed arc contact 5 in contact with the movable arc contact 9 and the fixed arc contact 5 by the lifting operation of the opening / closing mechanism 15, and the arc between the contacts is pulled. The main part of the current is transferred to the movable arc contact 9 and the fixed arc contact 5. The movable element 7 is rotated counterclockwise by the operation of the opening / closing mechanism 15 and the movable arc contact is 9 and the fixed-side arc contact 5 are separated, and the arc generated here is induced by the arc extinguishing device 17 and extinguished.

In addition, in the closing operation, the movable element 7 rotates clockwise by the closing operation of the opening / closing mechanism 15, and the movable-side arc contact 9 and the fixed-side arc contact 5 first come into contact with each other, so that electricity can be supplied. When the movable contact 6 and the fixed contact 3 are pressed against each other by further pushing the opening / closing mechanism 15, the movable element 7 rotates counterclockwise, and the movable arc contact 9 and the fixed arc contact 5 are separated from each other. Power is transferred to movable contact 6 and fixed contact 3.

In the conventional air circuit breaker as described above, the arc generated at the time of current interruption is transferred to the movable-side arc contact 9 and the fixed-side arc contact 5, and the arc is extinguished by the arc extinguishing device 17. For this reason, in order to withstand wear due to arc sparks at the time of current interruption, it is necessary to use tungsten-silver alloy contacts for the fixed-side arc contact 5 and the movable-side arc contact 9 in order to prevent welding of the arc contacts described later. Was.

The present invention has been made in order to solve such a problem, and it is easy to extinguish an arc by current limiting without using a tungsten-silver alloy contact as an arc contact for inducing an arc to an extinguishing device 17. The purpose is to provide an inexpensive air circuit breaker that does not easily cause arc contact welding. Disclosure of the invention

An air circuit breaker according to the present invention includes a fixed contact fixed to a fixed conductor, a mover having a movable contact fixed to and separated from the fixed contact, a switching mechanism for automatically opening and closing the mover, and a fixed conductor. A fixed-side arc contact provided at the tip of a fixed-side arc conductor extending from the movable element via a first resistor, and a movable-side arc extending from a movable element via a second resistor. And a movable arc contact provided at the tip of the conductor. When the contact is in contact with the fixed contact, the movable contact is brought into contact with the fixed contact, the movable contact and the fixed contact are brought into contact, and then the movable contact and the fixed arc contact are separated and turned off. In this case, the movable arc contact and the fixed arc contact are brought into contact with each other, the movable contact and the fixed contact are separated, and then the movable arc contact and the fixed arc contact are automatically opened and closed. .

Further, the resistor is provided only on one of the mover side and the fixed conductor side. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view of a main part of an air circuit breaker according to the present invention.

FIG. 2 is a transparent perspective view of an energizing portion of the air circuit breaker of the present invention.

FIG. 3 is a diagram for explaining the switching operation of the air circuit breaker of the present invention. FIG. 4 is a side sectional view of a conventional air circuit breaker. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1, '

FIG. 1 is a cross-sectional view of a main part of an air circuit breaker according to Embodiment 1 of the present invention, FIG. 2 is a perspective view of a current-carrying portion of the air circuit breaker of the present invention, and FIG. It is a figure explaining opening and closing operation of a middle circuit breaker.

In the figure, reference numerals 1 to 4, 6 to 8, and 10 to 17 are the same as those of the above-described conventional device, and the description is omitted. Reference numeral 4a denotes a fixed-side arc contact provided at the tip of the fixed-side arc conductor 4, and 31 denotes a first resistor that is held between the fixed conductor 2 and the fixed-side arc conductor 4 so as to be able to conduct electricity. Reference numeral 8a denotes a movable-side arc contact provided at the tip of the movable-side arc conductor 8, and 32 denotes a ^second resistor provided so as to be able to conduct between the mover 7 and the movable-side arc conductor 8. . The operation of the air circuit breaker of the present invention will be described with reference to FIG. Fig. 3 (A) shows the on state of the air circuit breaker, in which the fixed contact 3 and the movable contact 6 are in contact, and the fixed-side arc contact 4a and the movable-side arc contact 8a are separated. Therefore, the current flows through the fixed conductor 2 → the fixed contact 3 → the movable contact 6 → the movable element 7 → the flexible conductor 13 → the terminal conductor 12.

The opening / closing mechanism 15 lifts the shaft 16 by detecting the excessive current, and the movable element 7 is rotated clockwise by the pressing force of the contact pressure panel 14 from the fixed contact 3 to the movable contact 6 Is slightly opened, and electric current is applied between both contacts by an arc. As the rotation of the mover 7 progresses, the movable-side arc contact 8a comes into contact with the fixed-side arc contact 4a, and the state shown in FIG. 3B is obtained. Here, the conduction current is fixed conductor 2 → first resistor 3 1 → fixed-side arc conductor 4 → fixed-side arc contact 4a → movable-side arc contact 8a → movable-side arc conductor 8 → second resistor 3 2 → mover 7 → flexible conductor 13 → terminal conductor 12 The first resistor 31 and the second resistor 32 inserted into this current path limit the current supplied by the resistance. Due to this current limiting action, the fixed-side arc contact 4a and the movable-side arc contact 8a are separated while the fault current is limited, resulting in the state shown in Fig. 3 (C). . At this time, an arc is generated between the fixed-side arc contact 4a and the movable-side arc contact 8a, but the arc is easily extinguished because the arc energy is reduced by the current limit.

In addition, when the air circuit breaker is turned on in a state where a considerably large current flows, a welding phenomenon at the contact points occurs. However, the welding according to the configuration of the present invention reduces the welding. The reason is explained below. By the closing operation of the opening / closing mechanism 15, the movable-side arc contact 8a first comes into contact with the fixed-side arc contact 4a, and a current flows between the two contacts.

Both contacts slightly open due to impact repulsion at the time of injection, flow into this gap The electric current generates an arc, the high temperature of which melts both contact surfaces. In this state, when the two contacts re-contact each other and the arc disappears, the molten portion on the contact surface cools and welding occurs. As a countermeasure, silver alloy contacts, which are hard to melt, are generally used for contacts.

In the configuration of the present invention, since the mover 7 is configured to move at the time of ON / OFF, the current when the movable-side arc contact 8a comes into contact with the fixed-side arc contact 4a is the second current. Since the current is limited by the first resistor 31 and the second resistor 32, the arc energy that causes welding is weakened.

Even if welding occurs between the fixed-side arc contact 4a and the movable-side arc contact 8a, the mover 7 is used as a fulcrum until the movable contact 6 contacts the fixed contact 3 at this contact. Since the contact portion is depressed in the counterclockwise direction, the contact portion is welded and peeled off by leverage. Then, when the movable contact 6 and the fixed contact 3 come into contact with each other, the current is transferred to the movable contact 6 and the fixed contact 3 having low resistance, and thereafter, the contact portion between the fixed-side arc contact 4 a and the movable-side arc contact 8 a is changed. Since they are separated, there is no arc generation at this location and there is no wear due to the arc of both contacts'. Therefore, the fixed-side arc conductor 4 and the movable-side arc conductor 8 including the fixed-side arc contact 4a and the movable-side arc contact 8a may be made of a normal copper-based conductive material. The need for alloy arc contacts is eliminated.

The first resistor 31 and the second resistor 32 may be steel plates having a higher specific resistance than steel, instead of a special resistance alloy.

In the above description, the first resistor 31 and the second resistor 32 are provided on both the fixed-side arc conductor 4 and the movable-side arc conductor 8, respectively. Is obvious. Industrial applicability As described above, the air circuit breaker of the present invention comprises an opening / closing mechanism 15 for manually opening and closing the mover 7, and a first resistor interposed between the fixed conductor 2 and the fixed-side arc contact 4a. A body 31 and a second resistor 32 interposed between the mover 7 and the movable-side arc contact 8a. When the opening / closing mechanism 15 turns on the mover 7, the movable-side arc is provided. The contact 8a is brought into contact with the fixed-side arc contact 4a to bring the movable contact 6 and the fixed contact 3 into contact, and then the movable-side arc contact 8a and the fixed-side arc contact 4a are separated. When turning off, the movable-side arc contact 8a and the fixed-side arc contact 4a are brought into contact with each other, and the movable contact 6 and the fixed contact 3 are separated from each other. When the contact 4a is automatically opened and closed, the current flowing through both contacts during opening and closing can be extinguished by the current limit of the first resistor 31 and the second resistor 32. And then, since the hardly occurs welding of arcing contacts, can be provided inexpensively air circuit breaker in the unnecessary Tandasute Hmm silver alloy contacts arcing contact.

Claims

The scope of the claims

1. A fixed contact fixed to the fixed conductor, a movable element to which a movable contact that contacts and separates from the fixed contact is fixed, an opening / closing mechanism for swingably opening and closing the movable element, and a first resistor from the fixed conductor. A fixed-side arc contact provided at the tip of the fixed-side arc conductor extending to the arc extinguishing device side, and extending from the mover to the arc extinguishing device side via a second resistor; A movable arc contact provided at the tip of the movable arc conductor.

When the movable element is turned on, the movable arc contact is brought into contact with the fixed arc contact to bring the movable contact into contact with the fixed contact. The movable arc contact and the fixed arc contact are separated from each other. When the movable arm is turned off, the movable arc contact and the fixed arc contact are brought into contact with each other. An air circuit breaker, wherein the movable-side arc contact and the fixed-side arc contact are separated after separating the fixed contact and the fixed contact.

2. The air circuit breaker according to claim 1, wherein the resistor is provided only on one of the mover side and the fixed conductor side.