JP2010015724A - Arc extinguishing device of circuit breaker unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arc extinguishing device of a circuit breaker unit in which scattering of metal particles into a space from a tip part of a fixed contactor to a movable contactor is restricted with a simple change and a short circuit breaking capacity is increased. <P>SOLUTION: A tongue piece 12c protruding a prescribed amount toward the base direction of the movable contactor which is wider than the width of the movable contactor is installed at the bottom part of an opening P of a separation plate 12b, and the right and left of a space in which a fixed contact and a movable contact make a contact and separation movement is covered by a side plate 12a made of an insulating member. The tongue piece 12c is continuously formed from the separation plate 12b, and the separation plate 12b and the side plate 12a are connected through a bottom frame 12d of the arc extinguishing device, and furthermore, the four members of the side plate 12a, the separation plate 12b, the tongue piece 12c, and the bottom frame 12d are formed by bending one sheet of insulating plate. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an arc extinguishing device for a circuit breaker.

  In the circuit breaker, when an internal contact is opened due to an overcurrent or the like, an arc is generated between the contacts during the opening operation. Since this arc deteriorates surrounding breaking mechanism components and causes a reduction in dielectric strength, the circuit breaker incorporates an arc extinguishing device so as to cover the contact portion, and the surrounding members are exposed to the arc. In addition, the dielectric breakdown voltage is prevented from lowering. For example, what is disclosed in Patent Document 1 covers the left and right sides of the contact / separation space where the contact makes contact / separation operation with side plates, and arranges a barrier (separation plate) between the contact / separation space and the opening / closing mechanism. By doing so, the generated arc is restricted from entering the opening / closing mechanism.

  FIG. 5 is a cross-sectional explanatory view showing a specific configuration of a circuit breaker equipped with such an arc extinguishing device, wherein 21 is an operation handle, 22 is a power supply side terminal, 23 is a load side terminal, and 24 is a fixed contact. A fixed contact provided with 24a, 25 a movable contact provided with a movable contact 25a, 26 an arc extinguishing device, and 27 an open / close mechanism. The arc extinguishing device 26 includes side plates 30 on the left and right sides of the contact / dissipation space where the fixed contact 24 a and the movable contact 25 a are arranged, and the separator plate 31 so as to sandwich the movable contact 25 on the left and right of the movable contact 25. It is configured to regulate the scattering of arc.

JP-A-8-185785

In recent years, there is a demand to increase the short-circuit breaking capacity of a circuit breaker due to changes in the installation environment of power receiving equipment. For example, in the past, it was sufficient to maintain a good withstand voltage with respect to the breaking operation when a current of 2.5 kA was energized. A circuit breaker that maintains the breakdown voltage is desired.
However, with the conventional structure as it is, it is difficult to increase the short-circuit breaking capacity, in particular, the short-circuit breaking capacity between the same poles, and it may be necessary to change the design of a plurality of members. A configuration that can easily cope with an increase was desired.

In FIG. 5, a dotted line B <b> 2 shows how the metal particles are scattered with the generation of the arc. When the movable contact 25a deviates, the current contact may be formed due to a decrease in insulation resistance between the stationary contact 24 and the movable contact 25 due to metal particles scattered by the generation of an arc. This is a path indicated by an arrow C from the distal end of 24 to the base of the movable contact 25 via the circuit breaker housing. As can be seen from the dotted line B2, metal particles are scattered along the path of the arrow C.
This is because the separator 31 is provided also on the movable contact 25 side to restrict the scattering of the metal particles, but the metal particles are scattered toward the base of the movable contact through the operation space of the movable contact 25. Therefore, it was difficult to regulate metal particles that scatter out of the contact / dissociation space through this space.

  Therefore, in view of such problems, the present invention limits the scattering of metal particles to the space from the fixed contact tip to the movable contact with a simple change, and eliminates the circuit breaker that can increase the short-circuit breaking capacity. An object is to provide an arc device.

In order to solve the above-mentioned problem, in the invention of claim 1, a fixed contact provided with a fixed contact and a movable contact provided with a movable contact are arranged to face each other, and the movable contact contacts / The movable contact is swingable in a predetermined direction so as to perform a detachment operation, and an arc generated between the fixed contact and the movable contact is formed around the intermediate portion of the movable contact in the direction of the movable contact base. An arc extinguishing device for a circuit breaker in which a separator for restricting entry into the circuit breaker is disposed, wherein the separator has an opening that allows the movable contact to swing, It is formed by notching from an end portion in the divergence direction, and includes a tongue piece that is wider than the movable contact width and protrudes by a predetermined amount toward the base of the movable contact at the bottom of the opening. To do.
According to this configuration, the separators restrict the metal particles from being scattered in the direction of the base of the movable contact upon receiving an arc generated when the electric circuit is cut off. Moreover, the range from the front of the fixed contact in the direction of the back surface of the tongue to the movable contact base is shielded by the tongue, and can be isolated from the scattering of the metal particles. Therefore, it is possible to prevent the insulation resistance from being deteriorated due to the interruption operation, and to increase the short-circuit interruption capacity. And it can respond only by the simple change which provides a tongue piece in a separator, and since it does not require the design change etc. of a circuit breaker housing | casing, it does not increase a cost.

According to a second aspect of the present invention, in the first aspect of the invention, the left and right sides of the contact / displacement space in which the fixed contact and the movable contact are in contact / displacement are covered with side plates made of an insulating member, and the separator Is arranged between the left and right side plates adjacent to the side plate.
According to this configuration, the horizontal scattering of the metal particles scattered by the electric circuit interruption operation is interrupted, and a decrease in insulation resistance between adjacent different polarities can be prevented. In addition, it is possible to eliminate the generation of a gap between the side plate and the separator plate, and it is possible to improve the closing property of the contact / separation space.

According to a third aspect of the present invention, in the invention of the second aspect, the tongue piece is formed continuously from the separator plate, and the separator plate and the side plate form a bottom frame of the arc extinguishing device. The four members of the separator plate, the side plate, the tongue piece, and the bottom frame are formed by bending a single insulating plate.
According to this configuration, since the tongue piece is continuously formed on the separator plate, it is only necessary to bend, and the side plate, the separator plate, and the tongue piece can be formed by punching one insulating plate. Therefore, it can be easily created and is easy to handle because it is connected.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the protruding length of the tongue piece is 3 to 7 mm.
According to this configuration, the scattering direction of the metal particles can be well controlled, and the swinging of the movable contact is not hindered.

According to the present invention, the tongue piece shields the range from the front of the fixed contact in the direction of the back surface of the tongue piece to the movable contact base, and can be isolated from the scattering of the metal particles. Therefore, it is possible to prevent deterioration of the insulation resistance and increase the short-circuit breaking capacity. And it can respond only by the simple change which provides a tongue piece in a separator, and since it does not require the design change etc. of a circuit breaker housing | casing, it does not increase a cost.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional explanatory view of a circuit breaker incorporating an arc extinguishing device according to the present invention, and FIG. 2 is an enlarged view of a portion A of FIG. 1 and 2, 1 is an operation handle for opening and closing an electric circuit, 2 is a power supply side terminal, 3 is a load side terminal, 4 is a fixed contact having a fixed contact 4a, and 5 is in contact with the fixed contact 4a. A movable contactor having a movable contact 5a that performs a separation operation, 6 an arc extinguishing device that extinguishes an arc generated between the contacts, 7 an open / close operation of the movable contact 5 in response to an operation of the operation handle 1, An open / close mechanism unit 8 that causes the movable contact 5 to be separated in response to occurrence of an overcurrent or a short circuit current, and 8 is a plunger for detecting a short circuit current or the like. The operation handle 1 is disposed on the upper surface of the circuit breaker housing 10, the power supply side terminal 2 is disposed rearward, and the load side terminal 3 is disposed forward.

  The arc extinguishing device 6 is formed of a metal frame 11 and an insulating frame 12 covering the frame 11, FIG. 3 (a) is a perspective view of the frame 11, and FIG. 3 (b) is an insulating frame. A perspective view of the body 12 is shown. The insulating frame 12 is formed by punching an insulating paper made of vulcanized fiber, and each surface is bent so as to be overlapped with the frame 11 so as to cover the contact / divergence space where the fixed contact and the movable contact are arranged. Is done.

  The insulating frame 12 will be described in detail. 12a is a side plate disposed so as to be opposed to the left and right of the contact / divergence space, and 12b is disposed at an intermediate portion of the movable contact 5 serving as a back portion of the movable contact 5a. A separator 12c is a tongue piece that protrudes in the base direction of the movable contact 5 from the separator 12b. Reference numeral 12d denotes a bottom frame that forms the bottom of the insulating frame 12, that is, the bottom of the arc extinguishing device, and is formed in a substantially U-shape to connect the side plate 12a and the separator 12b.

  The side plate 12a is formed in a quadrangular shape and has a size that covers the left and right sides of the contact / divergence space. The separating plate 12b is disposed adjacent to the end of the side plate 12a on the side of the movable contact 5, and the movable contact 5 is inserted through the center, and the opening P that allows the swing is cut out from above. The whole is formed in a substantially U shape.

On the other hand, the tongue piece 12c is continuously formed on the separating plate 12b which is the bottom of the opening P, and the width W has a width substantially equal to the width of the opening P (for example, 9 mm) and is substantially perpendicular to the separating plate 12b. It is formed by bending, and the protruding length T is about 5 mm. The side plate 12a and the front plate 12b are integrally formed with a bottom frame 12d formed in a U-shape. That is, the side plate 12a, the separator plate 12b, the tongue piece 12c, and the bottom frame 12d are integrally formed by punching out one insulating plate, and each member is formed by bending.
The protrusion length T of the tongue piece 12c is preferably 3 to 7 mm because a metal particle shielding function described later is lowered when the tongue piece 12c is short and the swinging operation of the movable contact 5 is hindered when it is long.

  FIG. 4 is an explanatory diagram in which a state where metal particles are scattered by an arc generated during the breaking operation in the circuit breaker of FIG. 1 is added by a dotted line B1. As shown in FIG. 4, the metal particles are scattered outside the arc extinguishing device 6 in the front-rear direction and the upper direction that are not blocked by the frame body 11 and the insulating frame body 12, and in the direction of the movable contactor 5 on the front side. In contrast, it is scattered in the direction of the base of the movable contact 5. However, the tongue 12c shields the bottom of the casing that is in front of the stationary contact 4 and is isolated from the scattering of the metal particles. As a result, it becomes difficult to form a current path as shown by the arrow C in FIG.

  Table 1 shows specific short circuit interruption test results, comparing the conventional configuration shown in FIG. 5 without the tongue piece with the configuration shown in FIG. 1 provided with the tongue side 12c. The test was performed with a circuit breaker with three terminals L1, N, and L2, and the input angle was set at three current phases: 0 °, 60 °, and 120 °. The resistance between the side terminal and the load side terminal) and the insulation resistance value (unit: MΩ) between the different polarity terminals. The energization current was 5.0 kA, the voltage between L1 and N and the voltage between L2 and N were 100V, and the voltage between L1 and L2 was 200V.

  From Table 1, when the tongue piece 12c is not provided, the insulation resistance of the same polarity is greatly reduced in the L1 phase and the L2 phase, but the configuration provided with the tongue piece 12c has a minimum of 20 MΩ and maintains good insulation characteristics. I understand that

Thus, the separator restricts the scattering of metal particles toward the base of the movable contact upon receiving an arc generated when the electric circuit is cut off. Moreover, the range from the front of the fixed contact in the direction of the back surface of the tongue to the movable contact base is shielded by the tongue, and can be isolated from the scattering of the metal particles. Therefore, it is possible to prevent deterioration of the insulation resistance due to the interruption operation, and to increase the short-circuit interruption capacity. And it can respond only by the simple change which provides a tongue piece in a separator, and since it does not require the design change etc. of a circuit breaker housing | casing, it does not increase a cost.
In addition, the side plate blocks the horizontal scattering of the metal particles scattered by the electric circuit blocking operation, and can prevent a decrease in insulation resistance between adjacent different polarities. Furthermore, by arranging the separating plate adjacent to the side plate, it is possible to eliminate the generation of a gap between them, and to improve the closing property of the contact / dissociation space.
In addition, since the tongue piece is continuously formed on the separator plate, it only needs to be bent, and the side plate, the separator plate, and the tongue piece can be formed by punching one insulating plate. Therefore, it can be easily created and is easy to handle because it is connected.

  In addition, although the said embodiment demonstrated the structure which has arrange | positioned the fixed contact 4 and the movable contact 5 toward the front-back direction used as the terminal direction of a circuit breaker, it is not limited to this direction, for example, The present invention can also be applied to a configuration in which the vertical direction orthogonal to the terminal direction is arranged. The separator 12b may be arranged in the middle of the movable contact 5 and the tongue piece 12c may be protruded toward the base of the movable contact.

It is a section explanatory view of a circuit breaker which shows an example of an arc extinguishing device of a circuit breaker concerning the present invention. It is the A section enlarged view of FIG. It is a perspective view of the arc-extinguishing apparatus of FIG. 1, (a) has shown the metal frame, (b) has shown the insulation frame. In the circuit breaker of FIG. 1, it is explanatory drawing which added the mode that a metal particle scattered by the generated arc. It is sectional explanatory drawing of the conventional circuit breaker.

Explanation of symbols

  6. Arc-extinguishing device, 12 ... Insulating frame, 12a ... Side plate, 12b ... Separating plate, 12c ... Tongue piece, 12d ... Bottom frame, P ... Opening.

Claims (4)

A fixed contact having a fixed contact and a movable contact having a movable contact are arranged opposite to each other, and the movable contact can be swung in a predetermined direction so that the movable contact is in contact with or separated from the fixed contact. A separator for restricting an arc generated between the fixed contact and the movable contact from entering the movable contact base is disposed around an intermediate portion of the movable contact. An arc extinguishing device for a circuit breaker,
The separator has an opening that allows the movable contact to swing, and is formed by cutting out from the end of the movable contact in the direction of separation.
An arc extinguishing device for a circuit breaker comprising a tongue piece at a bottom portion of the opening that is wider than a movable contact width and protrudes by a predetermined amount toward the base of the movable contact. The left and right sides of the contact / separation space in which the fixed contact and the movable contact contact / separate are covered with side plates made of an insulating member, and the separator is disposed adjacent to the side plates and disposed between the left and right side plates. An arc extinguishing device for a circuit breaker according to claim 1. The tongue piece is formed continuously from the separator plate, and the separator plate and the side plate are connected via a bottom frame that forms the bottom surface of the arc extinguishing device,
The arc breaker for a circuit breaker according to claim 2, wherein the four members of the separator plate, the side plate, the tongue piece, and the bottom frame are formed by bending a single insulating plate. The arc extinguishing device according to any one of claims 1 to 3, wherein a protruding length of the tongue piece is 3 to 7 mm.

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