WO2003015114A1

WO2003015114A1 - Air circuit breaker

Info

Publication number: WO2003015114A1
Application number: PCT/JP2001/006644
Authority: WO
Inventors: Junichi Kawakami; Hiroshi Okashita
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2001-08-02
Filing date: 2001-08-02
Publication date: 2003-02-20
Also published as: JPWO2003015114A1; JP4599799B2; TW517257B; CN1441956A; DE60143410D1; EP1414057A4; EP1414057A1; CN1226764C; KR100520928B1; EP1414057B1; ES2351204T3; KR20030055272A

Abstract

An air circuit breaker in which the short time conduction capacity is increased by suppressing floating and lateral shift of a movable contact point (6a), and retarding generation of arc from a contact plane. The air circuit breaker comprises a flexible conductor (7) of substantially U-shape formed by bending a movable contact (6) having the movable contact point (6a) in the switching direction such that the movable contact (6) can be switched a lever action shaft (6c) for converting an electromagnetic force in the spreding-out direction at the U-shaped part of the flexible conductor (7) produced by a conducting current into a pressing force of the movable contact point (6a), and a plurality of magnetic plates (13) arranged in parallel, through a magnetic gap (13a), between the U-shaped side face poles of the flexible conductor in order to enhance the electromagnetic force. The magnetic plate between each pole may be extended from the U-shaped side face to the side part of the switching contact.

Description

Description Air circuit breaker Technical field

The present invention relates to a multi-pole air circuit breaker for interrupting an excessive current, and more particularly to securing a short-time conduction capacity at a switching contact portion. d

— Kagegicho

FIG. 5 is a sectional side view of a main part of a conventional air circuit breaker disclosed in, for example, Japanese Patent Application Laid-Open No. 6-089650, and FIG. 6 is a switching contact of the conventional air circuit breaker. FIG. 7 is a perspective view showing the arrangement of magnetic members provided around a switching contact of a conventional air circuit breaker.

In the figure, 1 is an outer shell of an air circuit breaker, and 2 is a switching mechanism including a well-known toggle link. Since such an air circuit breaker requires a large throwing force, the spring force stored in the closing spring 2d by the ratchet 2b and the eccentric cam 2c by the charge handle 2a or a motor (not shown) is used. It is to be thrown.

A contact arm 4 is connected to a lower link 2 e of the opening / closing mechanism 2 via a connecting pin 3, and the contact arm 4 is rotatably supported by a contact arm pin 5. Reference numeral 6 denotes a movable contact. A movable contact 6a is fixed to one end, and a flexible conductor 7 in which thin conductors are laminated is connected to the other end. The end of the flexible conductor 7 is connected to the lower terminal 8, and the flexible conductor 7 is formed and arranged in a substantially U shape from the connection position of the lower terminal 8. In addition, the movable contact pin 6c is inserted through the fulcrum hole 6b provided near the center of the movable contact 6 and the support hole of the connection arm 4 to move. The contact 6 is swingably supported. Reference numeral 9 denotes an upper terminal, which is provided at one end with a fixed contact 9a which comes into contact with and separates from the movable contact 6a. Reference numeral 10 denotes a contact pressure panel that urges a connection portion with the movable contact 6 in a direction in which the U-shaped flexible conductor 7 is opened. This biasing force makes the movable contact 6 work clockwise in the drawing by using the movable contact pin 6c as a lever fulcrum, thereby bringing the movable contact 6a into contact with the fixed contact 9a. 11 is an arc extinguishing device that eliminates the arc generated between the contacts when current is interrupted. Reference numeral 12 denotes a magnetic plate disposed between the pole phases. The magnetic plate 12 is disposed so as to cover the U-shaped side of the flexible conductor 7, and enhances the electromagnetic force for suppressing the floating of the movable contact 6a when an excessive current described later is applied. It is a magnetic path.

Next, the contact pressing operation of the conventional air circuit breaker during an accident current will be described. When an excessive fault current is supplied to the air circuit breaker, the movable contact 6a normally pressed to the fixed contact 9a by the contact pressure panel 10 tends to be opened by electromagnetic repulsion. Since this excessive current passes through the flexible conductor 7, an electromagnetic force acts on the flexible conductor 7 in a direction to open the U-shape, so that even if the excessive current passes, no floating of the contacts occurs, and short-circuiting does not occur between the contacts. The time carrying capacity is increased.

However, the excessive fault current at the time of a load short circuit that such an air circuit breaker interrupts is three-phase alternating current, which passes through three poles simultaneously. For this reason, magnetic fluxes that are out of phase by 120 degrees simultaneously pass through the magnetic plates 12 disposed between the phases. For this reason, when the breaking current increases, the magnetic plate 12 is magnetically saturated in the in-phase region with the adjacent pole of the current, and the magnetic flux is canceled in the opposite-phase region, and the electromagnetic force (contact pressing force) that opens the U-shape of the flexible conductor 7 is obtained. Does not become larger than the increase in the current value, and the electromagnetic repulsive force between the fixed contact 9a and the movable contact 6a is superior, so that the contact is easily lifted. Therefore, even if the thickness of the magnetic plate 12 was increased, the effect of preventing the contact from being lifted as expected could not be obtained. Further, since the magnetic plate 12 is arranged only around the flexible conductor 7, the movable contact 6 is affected by the magnetic field of the adjacent pole and receives a lateral force due to the electromagnetic force with the self-pole current. This lateral force causes the movable contact 6a to move in the lateral direction, causing an arc between the movable contact 6a and the fixed contact 9a and causing a problem that the contact surface damage does not increase the current carrying capacity for a short time.

The present invention has been made to solve such a problem, and suppresses the influence of the magnetic flux of the adjacent pole even if the fault current increases, suppresses the floating of the fixed contact 9a and the movable contact 6a, and The purpose of the present invention is to obtain an air circuit breaker with a high current carrying capacity for a short time by suppressing the lateral displacement of the contact and making it difficult for the contact surface to be ignited. Disclosure of the invention

An air circuit breaker according to the present invention is a flexible conductor formed by bending a movable contact having a movable contact among open / close contacts in an opening / closing direction so as to be capable of opening / closing and a substantially u-shape; The lever shaft that converts the electromagnetic force in the direction of the U-shaped part into the pressing force of the movable contact and the magnetic plate that strengthens the electromagnetic force placed between the U-shaped side poles of the flexible conductor are arranged in parallel. It is made up of multiple sheets with magnetic gaps interposed between them.

Also, the magnetic plate between the poles extends from the u-shaped side surface of the flexible conductor to the side of the switching contact.

Then, a magnetic plate is inserted and arranged in an insertion groove formed with a gap corresponding to a magnetic gap in a phase gap wall that insulates and isolates a multipole switching contact.

In addition, the magnetic plate is divided into a U-shaped side arrangement of a flexible conductor and a magnetic shield plate of an open / close contact portion including a movable contact, and each of the provided insertion grooves is provided independently on the phase space wall. . Further, each magnetic plate and each magnetic shielding plate are formed of a laminate of magnetic thin plates. , Brief description of drawings

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

FIG. 2 is a diagram for explaining the mounting arrangement of the magnetic plate of the first embodiment on a box.

FIG. 3 is a diagram showing an arrangement of a magnetic plate provided around a switching contact portion according to a second embodiment.

FIG. 4 is a diagram showing an arrangement of a magnetic plate and a barrier material according to the third embodiment of the present invention.

FIG. 5 is a side sectional view of a main part of a conventional air circuit breaker.

FIG. 6 is a perspective view of a main part of a switching contact portion of a conventional air circuit breaker. FIG. 7 is a diagram showing an arrangement of magnetic members provided around a switching contact portion of a conventional air circuit breaker. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1

FIG. 1 is a vertical sectional view of a main part of an air circuit breaker according to Embodiment 1 of the present invention, and FIG. 2 is a diagram illustrating an arrangement of a magnetic plate of Embodiment 1 mounted on a box.

In the figure, 1 to 11 are the same as those in the above-described conventional apparatus, and the description is omitted. Reference numeral 13 denotes a magnetic plate, which is disposed on a U-shaped side of the flexible conductor 7.

This magnetic plate 13 is provided between each pole of the A magnetic air gap 13a is provided between the plates.

As shown in Fig. 2, the magnetic plate 13 is a box formed of an insulating resin material that forms the outer shell 1 of the air circuit breaker. It can be mounted in place by inserting it into groove 1b. The insertion groove 1b is provided at the center of the interphase wall 1a of the insulating resin material of the pace forming material so that a plurality of magnetic plates 13 can be mounted in parallel with securing the magnetic gap 13a. They are provided in parallel with each other.

In the air circuit breaker thus configured, the magnetic gap 13a separates the magnetic flux due to the current of the own pole and the magnetic flux due to the adjacent pole current, and there is a phase difference for each pole due to the multiple magnetic plates 13 Even with current, magnetic saturation and magnetic flux cancellation are reduced, so that the electromagnetic force (contact pressing force) that opens the U-shaped flexible conductor 7 tends to increase in proportion to the magnitude of the current. The floating of the contact due to the electromagnetic repulsion can be suppressed.

Therefore, the contact capacity does not rise when an excessive current is applied, so that the current carrying capacity can be increased for a short time. Embodiment 2

FIG. 3 is a diagram showing an arrangement of a magnetic plate provided around a switching contact portion according to a second embodiment. In the figure, 1, 6 to 9 are the same as those in the first embodiment. Reference numeral 14 denotes a plurality of magnetic plates. In the second embodiment, each magnetic plate 14 extends from the U-shaped side of the flexible conductor 7 to the side of the switching contact. The plurality of magnetic plates 14 are mounted and arranged by inserting them into insertion grooves (not numbered) provided in parallel with the magnetic gaps 13a provided in the phase gap walls 1a.

In this way, the magnetic plate 1 4 Since the magnetic plate 14 shields the circulating magnetic flux caused by the current of the adjacent pole, the movable contact 6 is prevented from causing lateral displacement due to its own current and the electromagnetic force of the adjacent circulating magnetic flux.

Accordingly, in addition to suppressing the electromagnetic force (contact pressing force) increasing the electromagnetic force (contact pressing force) for opening the U-shape of the flexible conductor 7 described in the first embodiment, the lateral displacement of the movable contact 6 can be suppressed, and further shortening can be achieved. The time capacity can be increased. Embodiment 3.

FIG. 4 is a diagram showing an arrangement of a magnetic plate provided around the switching contact portion according to the third embodiment. In the figure, 1, 6 to 9 and 13 are the same as those in the first embodiment. Reference numeral 15 denotes a magnetic shielding plate, which is provided between the respective pole phases on the side of the contact opening / closing portion of the movable contact 6 and the movable contact 6a and the fixed contact 9a separately from the magnetic plate 13. A reinforcing portion 1c is provided between the magnetic plate 13 and the magnetic shield plate 15.

In the second embodiment, a long insertion groove extending from the U-shaped side of the flexible conductor 7 to the side of the contact opening / closing portion is provided in the phase interval wall 1a, and the magnetic plate 14 is inserted and arranged in this groove. For this reason, the strong electromagnetic force applied to the magnetic plate 14 may cause cracks in the side wall of the insertion groove, and as a countermeasure, increasing the thickness of the spacing wall 1a increases the volume of the air circuit breaker. Not desirable. Therefore, the magnetic plate 13 is divided so that the magnetic path is secured and the magnetic shielding plate 15 is provided with the function of shielding the adjacent poles.When the power is cut off, the current carrying capacity does not decrease for a short time. With the thickness of the phase space wall 1a, the insertion grooves of the magnetic plate 13 and the magnetic shield plate 15 were made independent, and the reinforcing portion 1c was provided to prevent cracking of the phase space wall 1a. Then, the housing 1 integrally with the phase separation wall 1a is formed by molding an insulating resin into a molding die. Manufactured. The location of the reinforcing portion 1c is effective as a contact position of the pin for removing the box 1 from the molding die. In the above description, the magnetic shielding plate 15 is also a plurality of plates having the magnetic gap 13a, but the reinforcing plate 1c is provided from the aspect of securing the strength of the phase separation wall 1a, and the magnetic plate 13 is The configuration may be such that the number of the magnetic shielding plates 15 is one. Embodiment 4.

Next, arranging the magnetic plates 13 and 14 and the magnetic shielding plate 15 in a plurality of sheets with the magnetic air gap 13a therebetween eliminates the influence of the magnetic flux of the adjacent pole. Is larger than a single magnetic plate without magnetic air gap and a magnetic shield, and the heat generated by the magnetic plates 13, 14 and 15 due to eddy current loss in the normal rated current range Causes energy loss and increases the temperature of the air circuit breaker.

As a countermeasure, heat generation can be suppressed by reducing the eddy current loss by using the magnetic plates 13 and 14 and the magnetic shielding plate 15 which are laminated magnetic thin plates whose surfaces are weakly insulated. Industrial applicability

As described above, in the air circuit breaker of the present invention, the magnetic flux due to the current of the own pole and the magnetic flux due to the current of the adjacent pole are separated by the magnetic air gap 13a, and have a phase difference for each pole. However, since magnetic saturation and magnetic flux cancellation in the magnetic plate 13 are reduced, the electromagnetic force (contact pressure) for opening the U-shaped flexible conductor 7 increases in proportion to the magnitude of the current, Suppresses contact lift due to electromagnetic repulsion between contacts. In addition, the magnetic shielding plate 14 provided between the movable contact 6a and the fixed contact 9a at the contact opening / closing section is controlled by the current of the adjacent pole. This shields the orbiting magnetic flux and prevents the movable contact 6 from causing lateral displacement due to electromagnetic force with its own current.

Therefore, when an excessive current is applied, the floating and lateral displacement of the contact are eliminated, so that the current carrying capacity is increased for a short time.

Claims

The scope of the claims

1. A multi-pole open / close contact comprising a fixed contact and a movable contact; a flexible conductor having a movable contact having the movable contact bent in the opening / closing direction so as to be capable of being opened / closed; Disposed between a support shaft for leverage for converting the electromagnetic force in the expanding direction of the U-shape due to a supplied current into a pressing force of the movable contact, and a U-shaped side pole of the flexible conductor for enhancing the electromagnetic force. An air circuit breaker, comprising: a magnetic plate having a plurality of magnetic plates arranged in parallel, and a magnetic gap interposed therebetween.

2. The air circuit breaker according to claim 1, wherein the magnetic plate is extended between the poles of the multipole switching contact.

3. An interphase wall that insulates and isolates the multi-pole switching contacts provided on the insulating resin box that forms the outer shell of the air circuit breaker, and a hole formed in the interphase wall with a gap equivalent to a magnetic gap 3. The air circuit breaker according to claim 1, wherein a magnetic plate is inserted into the groove.

4. The flexible conductor is divided into a U-shaped magnetic plate arranged on the side and a magnetic shield plate for the switching contacts, including movable contacts, and the installation grooves are separately provided on the phase space walls. 4. The air circuit breaker according to claim 2, wherein the air circuit breaker is an air circuit breaker.

5. The air circuit breaker according to any one of claims 1 to 4, wherein the magnetic plate and each of the magnetic shielding plates are formed of a laminate of magnetic thin plates.