CN1226764C - Air circuit breaker - Google Patents

Abstract

The present invention relates to an air circuit breaker which comprises a flexible conductor (7), a bearing shaft (6c) and magnetic plates (13), wherein the flexible conductor (7) is bent to be in an approximate U shape in order to enable a movable contact (6) with a movable joint (6a) to opened or closed in the opening direction or closing direction; the electromagnetic force which is generated by energizing current and enables the U-shaped part of the flexible conductor (7) to act in the opening direction is converted into the lever action of the press force of the movable contact (6a) by the bearing shaft (6c); the magnetic plates (13) are forcefully arranged among the poles of the U-shaped side surface of the flexible conductor and are provided with electromagnetic force, a plurality of magnetic plates (13) are arranged in parallel, and magnetic gaps (13a) are formed between every two magnetic plates (13). the magnetic plates between every two poles can be extended to the side part of the opening-closing joint from the U-shaped side surface of the flexible conductor; thus, the movable joint (6a) is not floated, the joints are inhibited from broadways deviating, the electric arc is not easily generated between the joints, and the energizing capacity is enlarged in a short time.

Description

air circuit breaker

technical field

The invention relates to a multi-pole air circuit breaker for cutting off excessive current, in particular to a circuit breaker for ensuring the short-time conduction capacity of switch contacts.

Background technique

Fig. 5 is a side sectional view of main parts of a conventional air circuit breaker as shown in Japanese Patent Laid-Open No. 6-089650, Fig. 6 is a perspective view of a main part of a switch contact part of a conventional air circuit breaker, and Fig. 7 is a This is an arrangement diagram of the magnetic components around the switch contacts of a conventional air circuit breaker.

In the figure, 1 is the shell of the air circuit breaker, and 2 is the well-known toggle-type opening and closing mechanism. Such an air circuit breaker requires a large operating force, so it is operated by the spring force of the operating spring 2d using the charging handle 2a or an unshown motor, the pawl wheel 2b, and the eccentric cam 2c.

The contact rod 4 is connected to the lower link 2e of the opening and closing mechanism 2 through the connecting pin 3, and the contact rod 4 is rotatably supported by the contact rod pin 5. 6 is a movable contact, a movable contact 6a is fixed on one end thereof, and a flexible conductor 7 formed of laminated thin plate conductors is connected to the other end. The end of the flexible conductor 7 is connected to the lower terminal 8 and is arranged in a substantially U-shape from the connection position of the lower terminal 8 to the flexible conductor 7 . The movable contact pin 6c is inserted into the support hole 6b provided near the center of the movable contact 6 and the support hole of the contact rod 4 to support the movable contact 6 swingably. Reference numeral 9 denotes an upper terminal, and a fixed contact 9a is provided at one end so as to be in contact with and separate from the movable contact 6a. 10 is a contact pressure spring, which urges the connecting portion of the movable contact 6 in the direction of opening the U-shape of the flexible conductor 7 . This urging force acts on the movable contact 6 in a clockwise direction in the drawing with the movable contact pin 6c as a fulcrum, and becomes the contact force of the movable contact 6a on the fixed contact 9a. 11 is an arc suppression device for eliminating the arc generated between the contacts when the current is cut off. 12 is a magnetic pole arranged between each pole phase. The magnetic pole 12 is arranged so as to cover the U-shaped side of the flexible conductor 7, and prevents the movable contact 6a from floating when an excessive current is passed, which will be described later, so that it becomes a magnetic circuit that strengthens the electromagnetic force.

The following describes the contact pressing action of the traditional air circuit breaker when the accident current occurs. When an excessive accident current flows through the air circuit breaker, usually, the movable contact 6a pushed to the fixed contact 9a by the contact pressure spring 10 tends to separate under the action of the electromagnetic reaction force. Since the excessive current passes through the flexible conductor 7, the electromagnetic force acts in the direction in which the U-shape of the flexible conductor 7 opens, and even if the excessive current passes through the contact, it will not float, so that the electric arc can be increased without arcing between the contacts. Large short-time power-on capacity.

However, the excessive accident current of such an air circuit breaker when the breaking load is short-circuited is 3-phase current, and 3 poles pass through at the same time. Therefore, the lines of magnetic force that are out of phase by 120 degrees pass through the magnetic plates 12 arranged in alternate phases at the same time. Therefore, when the cut-off current increases, the magnetic plate 12 in the same-phase region as the adjacent pole of the current is magnetically saturated, and the magnetic force lines in the anti-phase region cancel each other out, opening the U-shaped electromagnetic force of the flexible conductor 7 (the contact is pressed Pressure) does not increase in proportion to the increase of the current value, so that the separation electromagnetic reaction force between the fixed contact 9a and the movable contact 6a wins, and the contact is easy to float. Therefore, even if the thickness of the magnetic plate 12 is increased, the desired effect of preventing contact lifting cannot be obtained.

In addition, since the magnetic plate 12 is arranged only around the flexible conductor 7, the movable contactor 6 is affected by the magnetic field of the adjacent pole and is acted on by the force in the lateral direction caused by the electromagnetic force of the self-pole current. There is a problem that the lateral force moves the movable contact 6a laterally, causing an arc between the movable contact 6a and the fixed contact 9a, causing damage to the contact surface and failing to improve the short-time conduction capacity.

The present invention is made to solve the above problems. The object of the present invention is to provide an air circuit breaker that can suppress the influence of magnetic force lines of adjacent poles even if the accident current increases, and can suppress the floating of the fixed contact 9a and the movable contact 6a, and contact The horizontal offset, the contact surface is not easy to arc, and a large short-time current carrying capacity can be obtained.

Contents of the invention

The air circuit breaker of the present invention includes: in order to make the movable contact with the movable contact among the open and close contacts open and close in the open and close direction, bend and shape into a substantially U-shaped flexible conductor; A support shaft that converts the electromagnetic force acting in the opening direction of the U-shaped portion of the flexible conductor into a lever-action support shaft that presses the movable contact; there are many magnetic plates that strengthen the electromagnetic force between the U-shaped side poles of the flexible conductor. arranged side by side, the gap becomes the magnetic gap.

Also, the magnetic plates between the poles are extended from the U-shaped side of the flexible conductor to the side of the switch contact.

In the interphase partitions that insulate and isolate the open and close contacts of the multi-poles, insertion grooves are pierced with gaps corresponding to the magnetic gaps, and magnetic plates are inserted and installed in the insertion grooves.

In addition, the magnetic plate is divided into a U-shaped side portion of the flexible conductor and a shield plate portion including the opening and closing contact portion of the movable contact, and each insertion groove is independently provided in the phase partition wall.

Each magnetic plate and each shield plate are composed of a laminated body of magnetic thin plates.

As described above, in the air circuit breaker of the present invention, the magnetic force lines generated by the current of the own pole and the magnetic force lines generated by the adjacent pole current are separated by the magnetic gap 13a. The current can also reduce the magnetic saturation at the magnetic plate 13 and the cancellation of the magnetic force lines. Therefore, the electromagnetic force (contact pressing force) for opening the U-shape of the flexible conductor 7 can be easily increased in proportion to the magnitude of the current, and the contact lifting caused by the electromagnetic reaction between the contacts can be suppressed. The magnetic plate 14 provided between the poles of the contact opening and closing part of the movable contact 6a and the fixed contact 9a can shield the magnetic force lines around the current of the adjacent poles, and prevent the movable contact 6 from being caused by the electromagnetic force of the self-pole current. offset.

Therefore, the contact point will not float and shift laterally when an excessive current is energized, and the short-time energization capacity can be increased.

Brief description of the drawings

Fig. 1 is a longitudinal sectional view of main parts of an air circuit breaker according to a first embodiment of the present invention.

Fig. 2 is an explanatory diagram for attaching the magnetic plate of the first embodiment to the housing.

Fig. 3 is an arrangement diagram of magnetic plates provided around switch contact portions according to the second embodiment.

Fig. 4 is an arrangement diagram of a magnetic plate and a shielding material according to a third embodiment.

Fig. 5 is a side sectional view of main parts of a conventional air circuit breaker.

Fig. 6 is a perspective view of main parts of an opening and closing contact portion of a conventional air circuit breaker.

Fig. 7 is an arrangement diagram of magnetic members provided around a switch contact portion of a conventional air circuit breaker.

BEST MODE FOR CARRYING OUT THE INVENTION

1st embodiment

Fig. 1 is a longitudinal sectional view of main parts of an air circuit breaker according to a first embodiment of the present invention, and Fig. 2 is a diagram illustrating attachment of a magnetic plate according to the first embodiment to a case.

1 to 11 in the figure are the same as those of the above-mentioned conventional device, and the description thereof is omitted here. 13 is a magnetic plate, which is arranged on the U-shaped side of the flexible conductor 7 .

The magnetic plate 13 is constituted by a plurality of magnetic plates disposed between the poles of the multi-pole switching portion, and a magnetic gap 13a is formed between the plates.

As shown in FIG. 2, the magnetic plate 13 is inserted and positioned in an insertion groove 1b provided in an interphase partition wall 1a of a base made of an insulating resin material forming the housing 1 of the air circuit breaker. The central part of the phase partition wall 1a made of insulating resin material of the base molding material is used as the magnetic gap 13a, and the insertion groove 1b is arranged in parallel to ensure the magnetic gap 13a by inserting a plurality of magnetic plates 13 in parallel.

In the air circuit breaker of this structure, the magnetic force lines generated by the current of the self-pole and the magnetic force lines of the adjacent pole current are separated by the magnetic gap 13a, even if the current with a phase difference between the poles is caused by a plurality of magnetic plates, it can be reduced. Magnetic saturation, magnetic force line offset. Therefore, the electromagnetic force (contact pressing force) for opening the U-shape of the flexible conductor 7 is easily increased in proportion to the magnitude of the current, and the contact lifting caused by the electromagnetic reaction between the contacts can be suppressed.

Therefore, the contacts will not float when the excessive current is energized, which can increase the short-term energization capacity.

Second Embodiment

Fig. 3 is an arrangement diagram of magnetic plates provided around switch contact portions according to the second embodiment. In the figure, 1, 6 to 9 are the same as those of the above-mentioned first embodiment. 14 is 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 switch contact. The plurality of magnetic plates 14 are inserted into insertion grooves (in no order) arranged in parallel with the magnetic gaps 13a provided in the phase partition walls 1a, and installed.

In this way, by extending the magnetic plate 14 to the side of the opening and closing contact that includes the movable contact 6, the magnetic plate 14 can shield the surrounding magnetic force lines caused by the current of the adjacent pole, and can prevent the movable contact 6 from being caused by the self-polarity. Lateral deflection is produced by the electromagnetic force generated by the electric current and the magnetic field lines around the adjacent poles.

Therefore, not only the contact lifting caused by the increase of the U-shaped electromagnetic force (contact pressing force) for opening the flexible conductor 7 described in the first embodiment can be suppressed, but also the lateral deviation of the movable contact 6 can be suppressed. Increase the short-time power-on capacity.

3rd embodiment

Fig. 4 is an arrangement diagram of a magnetic plate and a shielding material according to a third embodiment. 1, 6 to 9, and 13 in the figure are the same as those of the above-mentioned first embodiment. 15 is a shielding plate, which is different from the magnetic plate 13 and is arranged alternately between the poles of the movable contactor 6 and the side part of the contact opening and closing part of the movable contact 6a and the fixed contact 9a. The reinforcement part 1c is formed between the magnetic plate 13 and the shielding plate 15.

In the above-mentioned second embodiment, a very long insertion groove is provided in the phase partition wall 1a from the U-shaped side of the flexible conductor 7 to the side of the contact opening and closing part, and the magnetic plate 14 is inserted thereinto. Therefore, the strong electromagnetic force received by the magnetic plate 14 may cause cracks in the side walls of the insertion groove. As a countermeasure, a method of thickening the thickness of the interphase partition wall 1a can be adopted, but this will cause the volume of the air circuit breaker to increase and is not suitable. For this reason, a split structure is used, that is, the magnetic plate 13 has a function of securing a magnetic circuit, and the shield plate 14 has a function of shielding adjacent poles. In this way, when the energization is cut off, there is no short-term decline in the conduction capacity. With the thickness of the conventional interphase partition wall 1a, the insertion grooves of the magnetic plate 13 and the shielding plate 15 can be independent, and the reinforcing part 1c is provided. This structure can prevent Cracks are generated in the phase partition wall 1a. Furthermore, the case 1 and the interphase partition walls 1a are integrally formed by an insulating resin mold. When the casing 1 is taken out from the mold, the reinforcing portion 1c can be an effective abutting position of the push pin.

The shielding plate 15 in the above description is composed of a plurality of shielding plates having magnetic gaps 13a, but it may also be configured to ensure the strength of the interphase partition wall 1a by having a reinforcing portion 1c, and the magnetic plate 13 has a plurality of magnetic plates 13. There is one shield plate 15 .

Fourth Embodiment

Next, a plurality of magnetic plates 13, 14 and shielding plate 15 are arranged with magnetic gaps 13a interposed therebetween. At this time, although there is no influence of the magnetic force lines of the adjacent poles, the eddy current caused by the magnetic force lines around the poles is larger than that of a magnetic plate and shield plate composed of only one magnetic plate and shield plate without a magnetic gap, and is within the normal rated current range. The heating of the magnetic plates 13 and 14 and the shielding plate 15 caused by the eddy current loss of the eddy current becomes the cause of energy loss and temperature rise of the air circuit breaker.

As a countermeasure, the magnetic plates 13 and 14 and the shielding plate 15 are formed by laminating thin magnetic plates whose surfaces are subjected to weak insulation treatment, thereby reducing eddy current loss and suppressing heat generation.

As mentioned above, the air circuit breaker of the present invention uses the magnetic gap 13a to connect the magnetic force lines generated by the current from one pole and the magnetic current lines generated by the current from adjacent poles so that the contact points do not float and the poles are enlarged by using offset magnetic plates. It can also reduce the offset of the magnetic saturation magnetic field lines at the magnetic plate 13. Therefore, the electromagnetic force (contact pressing force) for opening the U-shape of the flexible conductor 7 can be easily increased in proportion to the magnitude of the current, and the contact lifting caused by the electromagnetic reaction between the contacts can be suppressed. The magnetic plate 14 provided between the poles of the contact opening and closing part of the movable contact 6a and the fixed contact 9a can shield the magnetic force lines around the current of the adjacent poles, and prevent the movable contact 6 from being caused by the electromagnetic force of the self-pole current. offset.

Claims (7)

1. An air circuit breaker, said air circuit breaker comprising: a multi-pole opening and closing contact composed of a fixed contact and a movable contact, in order to make the movable contact with the movable contact open and close in the direction of opening and closing , and the flexible conductor bent into a substantially U-shape has a leverage that converts the electromagnetic force generated by the energized current and causes the U-shaped portion of the flexible conductor to act in the opening direction into the pressing force of the movable contact. The supporting shaft is arranged between the U-shaped side poles of the flexible conductor, and the magnetic plate for strengthening the above-mentioned electromagnetic force is characterized in that a plurality of the magnetic plates are arranged in parallel so that the gap becomes a magnetic gap. 2. The air circuit breaker according to claim 1, wherein the magnetic plate is extended between poles of multi-pole switching contacts. 3. The air circuit breaker according to claim 1, characterized in that, the air circuit breaker has interphase partitions that insulate and isolate the multi-pole opening and closing contacts, and the multi-pole opening and closing contacts are arranged to form the air circuit breaker On the shell made of insulating resin, an insertion groove is formed in the phase partition wall to form a magnetic gap, and a magnetic plate is inserted and set in the insertion groove. 4. The air circuit breaker according to claim 2, characterized in that, the air circuit breaker has interphase partitions that insulate and isolate the multi-pole switching contacts, and the multi-pole switching contacts are arranged to form the air circuit breaker On the shell made of insulating resin, an insertion groove is formed in the phase partition wall to form a magnetic gap, and a magnetic plate is inserted and set in the insertion groove. 5. The air circuit breaker according to any one of claims 3-4, characterized in that the magnetic plate is divided into a magnetic plate arranged on the U-shaped side part of the flexible conductor and a shielding plate of the opening and closing contact part, The opening and closing contact part includes a movable contact, and each insertion groove is independently provided in the interphase partition wall. 6. The air circuit breaker according to any one of claims 1-4, wherein the magnetic plate is composed of a laminated body of magnetic thin plates. 7. The air circuit breaker according to claim 5, wherein the magnetic plate and the shield plate are formed of a laminate of magnetic thin plates.

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