Patent Application
20120211469
The present disclosure relates to subject matter contained in priority Korean UM. Application No. 20-2011-0001489, filed on Feb. 22, 2011, which is herein expressly incorporated by reference in its entirety.
1. Field of the Invention
This specification relates to a circuit breaker with an arc extinguishing mechanism, and particularly, to a circuit breaker with an arc extinguishing mechanism for extinguishing arc generated when a movable contactor is separated from a stationary contactor due to a fault current.
2. Background of the Invention
A circuit breaker is an electric device for protecting a circuit and a line by automatically breaking such circuit or line upon occurrences of an electric overload state or a short-circuit state. In general, current flowing over an electric circuit is generally divided into a rated current and a fault current which flows due to a breakdown like short-circuit, grounding, etc.
The fault current is drastically larger than the rated current, so it is difficult to be cut off. Accordingly, the circuit breaker is designed to block both the rated current and the fault current. A rated switch is able to merely block a current, which is as low as the rated current, so it is distinguished from the circuit breaker. An electric power system includes a power generator, a transformer, a power transmission line and the like. When desiring to suspend some of them, a current of the power generator or power transmission line desired to be suspended is blocked by a circuit breaker such that the power generator or power transmission line can be isolated from the electric power system. Also, when a breakdown such as short-circuit or grounding is caused in the system, an extremely large fault current flows over the system. If the system is left in that state, it may aggravate damage on the broken component or portion and the other may also be out of order due to large current. Thus, the circuit breaker is used for blocking the broken portion.
In general, the circuit breaker exhibits more excellent current limitation when it has superior arc extinguishing capability and takes a shorter time to break current.
As shown in
As shown in
An operation of the arc extinguishing mechanism of the related art circuit breaker is described as follows.
Referring to
However, in the arc extinguishing mechanism of the related art circuit breaker, after arc generated due to a rotary motion of the mover 142 flows to the arc chute 143 through the arc runner 141b, when the arc is elongated within the arc chute 143, an arc column is not induced up to the upper grid 144, it is impossible to obtain a significant increase in an arc voltage. Also, the insulating plates 143b for supporting the grids 143a are unable to generate significant extinguishing gas due to arc energy. Hence, it is impossible to expect an increase in the arc voltage in response to an increase in pressure. Also, referring to
Therefore, to address the drawbacks of the related art, an aspect of the detailed description is to provide an arc extinguishing mechanism for a circuit breaker capable of uniformly distributing arc, generated upon breaking a fault current, into grids so as to improve arc extinguishing efficiency.
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 circuit breaker including a plurality of grids disposed in a longitudinal direction, each having protruding portions at both ends thereof so as to define a space therebetween, a fixing portion to support the grids, insulating plates fixed to both sides of the grids, a stator located below the grids, the stator including an arc runner and a stationary contact disposed at an upper side of the arc runner, and a mover contactable with or separated from the stationary contact with moving up and down within the space, wherein an interval between the insulating plates within the space is shorter than a width of the mover.
In accordance with the aspect, the interval between the pair of insulating plates can be shorter than a width of the mover, namely, end portions of the insulating plates can protrude into the space, so as to allow the generated arc to be more smoothly introduced into the grids and simultaneously increase an amount of arc extinguishing gas generated by the insulating plates, thereby improving an arc extinguishing performance.
Here, the insulating plates may include first insulating plates disposed at both sides of the grids, and second insulating plates coupled to the first insulating plates and extending into the space. Each of the second insulating plates may include a coupling portion coupled to the first insulating plate, and an inclined portion extending from the coupling portion toward the grids with an inclination.
Also, the second insulating plates may be located between the protruding portions of the grids and the mover.
In addition, the interval between the insulating plates within the space can be shorter than a width of the arc runner, to allow more arc to be introduced into the grids.
In accordance with the aspects of the present disclosure with the configuration, arc generated during a breaking operation can be introduced more into grids and a contact area between the arc and the insulating plates can be increased, resulting in enhancement of arc extinguishing efficiency.
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 a circuit breaker in accordance with 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.
Referring to
The grid 20 may be made of a metal having ferromagnetism. Protruding portion 22 may be formed at both ends at the front of each grid 20 based on
A fixing portion 30 may be installed at the rear of the grids 20. The fixing portion 30 may serve to fix the grids 20 such that the grids 20 can remain in the fixed state with the predetermined intervals. In addition, the fixing portion 30 may be secured with a circuit breaker main body (not shown).
First insulating plates 40 may be fixed to both side surfaces of the girds 20. The first insulating plates 40 may prevent arc leakage to the outside in cooperation with the upper grid 26 and also serve to fix the grids 20. The first insulating plates 40 may be made of a material, which is able to generate arc extinguishing gas when contacting arc, so as to rapidly extinguish such arc.
The first insulating plates 40 may be formed longer than the grids 20 such that their front sides can protrude from the front sides of the grids 20. Second insulating plates 50 may be fixed onto the protruded portions. Each of the second insulating plates 50, as shown in
A mover 60 may be installed at the front of the second insulating plates 50. The mover 60 may have the same structure as the mover of the typical circuit breaker. The mover 60 may include a plurality of movable contactors 62 disposed in series.
A stator 70 may be disposed below the mover 60. The stator 70 may include a stationary contact 72 contacting the mover 60, and an arc runner 74 to induce arc generated during a breaking process. Here, referring to
a<b<c
Hereinafter, description will be given of operations of the circuit breaker according to the one exemplary embodiment.
In a normal state that the mover 60 and the stator 70 contact each other to allow a current flow, when the mover 60 is separated by an electromagnetic repulsive force, which is generated between the stationary contact 72 and the mover 60 upon generation of a fault current due to a particular cause, arc is generated between the two electrodes. Here, the arc is induced to the arc runner 74 after staying at the stationary contact 72 for a short term of time. The arc induced to the arc runner 74 then generates arc extinguishing gas from the first and second insulating plates 40 and 50, which define inner walls of the arc extinguishing space.
Here, the generated arc extinguishing gas compresses and elongates an arc column by pressure, which is instantaneously rapidly risen in the arc extinguishing space, so as to render an arc voltage high, thereby improving a current limitation performance (efficiency). The arc then rapidly moves into the grids 20 by an attractive force and pressure by a magnetism generated by the grids 20, so as to be segmented and cooled.
Here, the second insulating plates 50 protrude into the arc extinguishing space, so the arc can generate the arc extinguishing gas by contacting the insulating plates 50 more rapidly. In addition, the inclined portions 54 of the second insulating plates 50 can additionally shield the arc extinguishing space. Accordingly, upon the arc generation, pressure within the arc extinguishing space can be further increased, which can make the arc diffused more rapidly into the grids 20.
The inclined portions 54 of the second insulating plates 50 can also prevent the arc from being reversely exhausted toward the mover 60. Consequently, metal particles, which are melted by heat gas and arc heat within the arc extinguishing space can be prevented from being exhausted toward the mover 60. This may result in prevention of damages of the stationary contact 72 and the mover 60 and prevention of reignition due to the reverse exhaust of the arc, which is ended up with improvement of a current limitation effect.
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 |
|---|---|---|---|
| 20-2011-0001489 | Feb 2011 | KR | national |
