Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2010-0053065, filed on Jun. 4, 2010, the contents of which is incorporated by reference herein in its entirety.
1. Field of the Invention
This specification relates to a mold cased circuit breaker capable of fast extinguishing arc, which is generated when a movable contactor is separated from a stationary contactor due to a fault current, by segmenting and cooling the generated arc and discharging arc pressure to the outside.
2. Background of the Invention
Generally, a mold cased circuit breaker is an electric protection apparatus, which is installed in an electric circuit to protect the circuit by preventing or minimizing damages on load equipment and lines due to fault currents (e.g., overload, short-circuit, etc.).
The circuit breaker typically includes a movable contactor, a stationary contactor, an arc-extinguishing device and the like. Upon occurrence of a fault current, the movable contactor is separated from the stationary contactor to trip a circuit and the circuit is protected accordingly. Here, when the movable contactor is separated from the stationary contactor, dielectric insulation in air is caused due to a current, thereby generating hot plasma arc state. Furthermore, gas is generated and accordingly arc pressure is generated. The thusly generated arc is segmented and cooled to be discharged outside, and a device performing such function is an arc-extinguishing device or an arc chamber.
The arc-extinguishing device generally has a structure that a plurality of grids are arranged in parallel. The grids absorb arc generated during tripping, thereby extinguishing the arc. Besides, various debris generated due to adjacent components being melted are adhered onto the grids, thus to reduce pressure within the circuit breaker, decrease erroneous operations of the circuit breaker, and increase an interruption capability.
However, such debris may be adhered on the movable contactor 50 or the stationary contactor 60 without entirely being adhered on the grids. Furthermore, the debris may be spread into the main body of the circuit breaker to thereby affect other components of the circuit breaker including the switching mechanism 40. The affection by the debris may cause an erroneous operation of the switching mechanism 40 of the circuit or interrupt the circuit, thereby lowering characteristics of the circuit.
Therefore, to improve the performance of the mold cased circuit breaker, a technique for effectively adhering such debris within the arc-extinguishing unit should be considered.
Therefore, an aspect of the detailed description is to provide an arc-extinguishing unit for a mold cased circuit breaker capable of preventing debris generated due to arc from being spread in the mold cased circuit breaker and adhering the debris on grids as much as possible.
Another aspect of the detailed description is to provide a mold cased circuit breaker capable of smoothly exhausting arc by increasing a space of the arc-extinguishing unit in a manner of allowing an interval between a grid and a movable contactor to be as wide as possible within an arc-inducible range, whereby erroneous operations of the mold cased circuit breaker can be reduced and an interruption capability of the mold cased circuit breaker can be improved.
To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, there is provided a mold cased circuit breaker having a casing, a switching unit disposed in the casing to open or close an electric circuit, and movable and stationary contactor units present within the casing, the circuit breaker including an arc-extinguishing unit, wherein the arc-extinguishing unit includes a pair of side plates facing each other with being spaced from each other, at least one first grid arranged between the side plates and spaced apart from one another with preset intervals, and a second grid coupled to upper ends of the side plates, spaced apart from the first grid, and having a bent portion with a preset angle.
Here, the casing may include an accommodating part configured to accommodate the arc-extinguishing unit therein, and a barrier defining a part of an outer wall of the accommodating part and protruding toward the arc-extinguishing unit, and one side surface of the second grid may be contactable with the barrier.
The barrier may include a contact part protruding with being stepped to have an inclination, and the contact part and the second grid may contact each other.
The second grid may include a horizontal part and a blocking part extending from the horizontal part by being bent from the horizontal part, and the horizontal part may contact the contact part. In addition, the horizontal part and the blocking part may form at least an acute angle.
Also, the second grid may be bent in an opposite direction to the movable contactor unit to form at least an acute angle.
Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments and together with the description serve to explain the principles of the invention.
In the drawings:
Description will now be given in detail of the exemplary embodiments, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and description thereof will not be repeated.
As shown in
The casing, as shown in
Referring to
Still referring to
The limit part 111 may protrude into the casing. The limit part 111 may allow the space for accommodating the arc-extinguishing unit to be further blocked from a space for accommodating the switching mechanism 400, thereby eventually minimizing or preventing spreading of debris.
The contact part 112 and the second grid may contact each other to block the space for accommodating the movable contactor unit 500 and the switching mechanism 400 from the upper portion of the accommodating unit 800. Accordingly, debris, which are generated upon extinguishing arc, can be adhered within the accommodating unit 800 as much as possible. Also, the second grid and the contact part 112 may contact each other at a position the most approached to the barrier 110, thereby increasing the inner space of the accommodating unit 800. Consequently, an interval between the grid and the movable contactor unit 500 may be defined as long as possible within an arc-inducible range and the space for the arc-extinguishing unit may be increased. Therefore, arc extinguishing can be carried out smoothly, thereby reducing mal-operations of the mold cased circuit breaker and improving interruption capability.
The switching mechanism 400 may include a handle, a spring, a latch and the like, and serve to mechanically operate the movable contactor unit 500. This structure is frequently used in the typical mold cased circuit breaker and thus will not be described in detail.
The movable contactor unit 500 may be operated by the switching mechanism 400, and include a movable contactor at its end. The movable contactor may be coupled to the movable contactor unit 500 by an adhesive agent or by a typical coupling member to thusly move integrally with the movable contactor unit 500. In general, the movable contactor has one end electrically connected to an output terminal side of a circuit and the other end contacting a stationary contactor, which is electrically connected to an input terminal side of the circuit, thereby allowing an electric short of the circuit.
The stationary contactor unit 600, as aforementioned, may include the stationary contactor electrically connected to the input terminal side, and, as shown in
Referring to
The pair of side plates 720 may have a structure of supporting the arc-extinguishing unit 700, and allow the arc-extinguishing unit 700 to be stably accommodated in the accommodating part 800 of the casing. As shown in
Referring to
Referring to
Referring back to
With the structure having the first grids 730 and the second grid 710, the plurality of grids can absorb arc generated during the trip operation so as to extinguish such arc. In addition, various types of debris generated due to melting of the adjacent components to the arc-extinguishing unit 700 can be adhered on the grids as much as possible, thereby reducing pressure within the mold cased circuit breaker, which results in reduction of erroneous operations of the mold cased circuit breaker and improvement of an interruption capability thereof.
Hereinafter, description will be given of operations of the mold cased circuit breaker having the configuration according to one exemplary embodiment with reference to the accompanying drawings.
In a normal state of the mold cased circuit breaker, the arc-extinguishing unit 700 is in a state shown in
When a fault current (e.g., overload, short-circuit, etc.) flows on the circuit, the movable contactor rotates in a counterclockwise direction in the drawing by the operation of the switching mechanism 400 so as to be in the state of
The arc, which is continuously generated in response to the rotation of the movable contactor, is gradually extinguished by the first grids 730 and the second grid 710. Also, debris generated during the arc extinguishing are adhered on the first grids 730 and the second grid 710. Especially, the second grid 710 is positioned more adjacent to the movable contactor unit 500 than the first grids 730. Accordingly, the second grid 710 induces more arc so as to more easily extinguish the arc. Also, a distance between the first grids 730 and the movable contactor unit 500 becomes sufficient to form an extra space more in the arc-extinguishing unit 700.
In addition, since the second grid 710 is located more adjacent to the movable contactor unit 500 than the first grids 730 and bent with forming an acute angle, the debris generated within the arc-extinguishing unit 700 may eventually be blocked by the second grid 710, thereby efficiently preventing the debris from being spread into the mold cased circuit breaker, which will be noticed more obviously with reference to
This specification can provided the following effects by virtue of the configuration of the mold cased circuit breaker.
The second grid, which is bent away from the movable contactor unit to form a preset angle, may be provided and one side surface of the second grid may be contactable with the barrier, thereby minimizing debris generated due to arc from being spread into the mold cased circuit breaker and allowing such debris to be adhered onto the grids as much as possible.
Also, the second grid, which is bent away from the movable contactor unit to form a preset angle, may be provided, thereby ensuring the farthest distance between the second grid and the movable contactor unit within an arc-inducible range, resulting in an increase in a space of the arc-extinguishing unit.
Consequently, arc can be smoothly extinguished, which results in reduction of erroneous operations of the mold cased circuit breaker and improvement of an interruption capability thereof.
The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments.
As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.
Number | Date | Country | Kind |
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10-2010-0053065 | Jun 2010 | KR | national |