Air circuit breaker

Abstract

The present invention relates to an air circuit breaker, in which a recess is formed on one side or each of both sides of each contact plate provided in an insulating cage so as to reduce a contact area between a movable contactor and the contact plate when the movable contactor and the contact plate are brought into contact with each other, thereby preventing a contact portion between the movable contactor and the contact plate from being melted due to heat generation.

Claims

1. An air circuit breaker comprising: an insulating cage provided with a plurality of contact plates; movable contactors each inserted between the contact plates; and fixed contactors brought into contact with or separated from the movable contactors in response to a movement of the movable contactors, wherein each of the contact plates is provided with a recess, wherein the recess is inclined toward an inside of the contact plates from rear sides of the contact plates to front sides of the contact plates, wherein in a connected state, the movable contactors are pushed toward the insulating cage to be inserted between the contact plates and thus brought into contact with the contact plates, and wherein a middle part of the movable contactors does not contact the contact plates by the recess.

2. The air circuit breaker of claim 1, wherein the recess is formed on each of both side surfaces of the contact plate.

3. The air circuit breaker of claim 2, wherein the recess has a rectangular or circular section.

4. The air circuit breaker of claim 1, wherein the recess is located at a position adjacent to a contact portion between the movable contactor and the fixed contactor in a state that the movable contactor and the fixed contactor are brought into contact with each other.

5. The air circuit breaker of claim 1, wherein the contact plate and the insulating cage are made of different materials from each other.

6. An air circuit breaker comprising: an insulating cage provided with a plurality of contact plates; movable contactors each inserted between the contact plates; and fixed contactors brought into contact with or separated from the movable contactors in response to a movement of the movable contactors, wherein each of both side surfaces of the contact plates is provided with a recess, wherein the recess has a rectangular or circular section, and wherein the recess is provided in plurality, and a depth of each of the recesses changes as the recess extends from a rear to front sides of the contact plate.

7. An air circuit breaker comprising: an insulating cage provided with a plurality of contact plates; movable contactors each inserted between the adjacent contact plates; and fixed contactors brought into contact with or separated from the movable contactors in response to a movement of the movable contactors, wherein each of the contact plates is provided with a recess, wherein the contact plate and the insulating cage are made of different materials from each other, and wherein the contact plate is made of a material having relatively higher thermal resistance than that of the insulating cage.

8. The air circuit breaker of claim 7, wherein the contact plate is made of a thermosetting or thermoplastic resin composite.

9. The air circuit breaker of claim 7, wherein the insulating cage is made of a thermosetting or thermoplastic resin composite.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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.

(2) In the drawings:

(3) FIG. 1 is a perspective view illustrating a breaking part of the related art air circuit breaker;

(4) FIG. 2 is an exploded perspective view illustrating the breaking part of the related art air circuit breaker;

(5) FIG. 3 is a cross-sectional view schematically illustrating a contact state between a movable contact and a fixed contact in the breaking part of the related art air circuit breaker;

(6) FIG. 4 is a front view illustrating a state in which a movable contactor is inserted between contact plates of the related art air circuit breaker;

(7) FIG. 5 is a front view illustrating a heat generating position between the movable contactor and the contact plate of the related art air circuit breaker;

(8) FIG. 6 is a perspective view illustrating a state in which the contact plates are provided in an insulating cage constituting the related art air circuit breaker;

(9) FIG. 7 is a schematic view illustrating relative positions of the movable contactor and the contact plate in a state before a movable contact and a fixed contact are brought into contact with each other in the related art air circuit breaker;

(10) FIG. 8 is a schematic view illustrating relative positions of the movable contactor and the contact plate in a state where the movable contact and the fixed contact are brought into contact with each other in the related art air circuit breaker;

(11) FIG. 9 is a perspective view illustrating an insulating cage provided in an air circuit breaker in accordance with one embodiment of the present invention;

(12) FIG. 10 is a schematic view illustrating relative positions of a movable contactor and a contact plate in a contact state between a movable contact and a fixed contact in the air circuit breaker in accordance with the one embodiment of the present invention;

(13) FIG. 11 is a perspective view illustrating contact plates provided in an insulating cage in accordance with another embodiment of the present invention;

(14) (a) of FIG. 12 is a perspective view illustrating a state before the contact plates and the insulating case provided in the air circuit breaker according to the one embodiment are coupled to each other;

(15) (b) of FIG. 12 is a perspective view illustrating a state where the contact plates and the insulating cage provided in the air circuit breaker according to the one embodiment are coupled to each other;

(16) (a) of FIG. 13 is a perspective view illustrating a state before the contact plates and the insulating cage provided in the air circuit breaker according to the another embodiment are coupled to each other;

(17) (b) of FIG. 13 is a perspective view illustrating a state where the contact plates and the insulating cage provided in the air circuit breaker according to the another embodiment are coupled to each other; and

(18) FIG. 14 is a flowchart illustrating a process of fabricating a breaking part of an air circuit breaker in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(19) Description will now be given in detail of an air circuit breaker according to exemplary embodiments disclosed herein, with reference to the accompanying drawings.

(20) FIG. 9 is a perspective view illustrating an insulating cage provided in an air circuit breaker in accordance with one embodiment of the present invention, FIG. 10 is a schematic view illustrating relative positions of a movable contactor and a contact plate in a contact state between a movable contact and a fixed contact in the air circuit breaker in accordance with the one embodiment of the present invention, and FIG. 11 is a perspective view illustrating contact plates provided in an insulating cage in accordance with another embodiment of the present invention.

(21) Also, (a) of FIG. 12 is a perspective view illustrating a state before the contact plates and the insulating case provided in the air circuit breaker according to the one embodiment are coupled to each other, (b) of FIG. 12 is a perspective view illustrating a state where the contact plates and the insulating cage provided in the air circuit breaker according to the one embodiment are coupled to each other, (a) of FIG. 13 is a perspective view illustrating a state before the contact plates and the insulating cage provided in the air circuit breaker according to the another embodiment are coupled to each other, (b) of FIG. 13 is a perspective view illustrating a state where the contact plates and the insulating cage provided in the air circuit breaker according to the another embodiment are coupled to each other, and FIG. 14 is a flowchart illustrating a process of fabricating a breaking part of an air circuit breaker in accordance with one embodiment of the present invention.

(22) As illustrated in FIGS. 9 and 10, the air circuit breaker according to the present invention, similar to the related art air circuit breaker, includes a breaking part (not illustrated) configured to allow a current to flow into or be cut off from the air circuit breaker. The breaking part includes fixed contactors fixed to one side of the breaking part, and movable contactors 200 brought into contact with or separated from the fixed contactors according to an operation of a switching mechanism (not illustrated). Each of the fixed contactors is connected to an input side terminal (not illustrated) through which a current is introduced, and provided with a fixed contact (not illustrated) at one end thereof to be brought into contact with or separated from a movable contact 210.

(23) The breaking part is further provided with an insulating cage 100 having a plurality of contact plates 110, a load side terminal (not illustrated) disposed on one side of the insulating cage 100, and braided wires (not illustrated) disposed within the insulating cage 10, connected to the load side terminal, and arranged in series toward another side of the insulating cage 100.

(24) In addition, the breaking part is provided with contact springs (not illustrated) disposed within the insulating cage 100 and elastically supporting the movable contactors 200.

(25) In this instance, as the air circuit breaker is turned on or tripped (or turned off), the movable contactor is brought into contact with or separated from the fixed contactor, in response to an operation of the switching mechanism. When the air circuit breaker is turned on, the movable contact 210 of the movable contactor 200 is brought into contact with the fixed contact of the fixed contactor. Accordingly, the movable contactor 200 is pushed toward the insulating cage 100 to be inserted between the contact plates and thus brought into contact with the contact plates 110.

(26) Meanwhile, each of the contact plates 110 is provided with a recess 111 to reduce a contact area with the movable contactor 200.

(27) The recess 111 is formed on one side surface of the contact plate 110. When the movable contactor 200 is inserted between the adjacent contact plates 110 to be brought into contact with the contact plates 110, a contact area between the movable contactor 200 and the contactor plate 110 is reduced due to the recess 111. This may result in preventing the contact portion between the movable contactor 200 and the contact plate 110 from being melted due to heat generated at the contact portion.

(28) That is, the air circuit breaker should be maintained in the ON state for a predetermined time even if a fault current is introduced, and accordingly, heat is generated at the contact portions so as to melt the contact portions between the movable contactors 200 and the contact plates 110.

(29) However, according to the present invention, the recess 111 is formed on the one side surface of the contact plate 110 to reduce the contact area at the contact position between the movable contactor 200 and the contact plate 110, thereby preventing the contact portion from being melted due to the generated heat.

(30) In this instance, the recess 111 may be formed on the one side surface of the contact plate 110 or on each of both side surfaces of the contact plate 110.

(31) As illustrated in FIG. 11, when the recess 111 is formed on each of both side surfaces of the contact plate 111, a thickness of the contact plate 110 may be reduced. Therefore, the number of recesses 111 may be adjusted according to a size of the insulating cage 100 or a thickness of the recess 111.

(32) Also, the recess 111 may be formed at a position adjacent to a contact portion between the movable contact 210 of the movable contactor 200 and the fixed contact of the fixed contactor 210 in the contacted state between the movable contactor 200 and the fixed contactor. Since the largest amount of heat is generated at the contact portion between the movable contact 210 and the fixed contact, the recess 111 may be located at a position adjacent to the contact portion, to reduce the contact area of the position which is most affected by the heat generated at the contact portion. Accordingly, the affection due to the heat can be minimized and thus the melting of the contact portion can be prevented more effectively.

(33) In addition, the recess 111 may be inclined inward the contact plate 110 from rear to front sides of the contact plate 110.

(34) That is, since the largest amount of heat is generated at the contact portion between the movable contactor 200 and the fixed contactor, the recess 111 is inclined the most deeply inward the contact plate 110 at the most adjacent position to the contact portion between the movable contactor 200 and the fixed contactor, so as to minimize the affection of the generated heat. Also, an inwardly-inclined degree of the recess 111 is reduced gradually as getting away from the contact portion, thereby preventing the contact portion from being melted due to the heat as much as possible.

(35) Meanwhile, the recess 111 may be configured to have a rectangular or circular section.

(36) That is, the recess 111 may be formed in a shape of a plate (rectangular section) or a cylindrical shape (circular section), and provided in plurality on both side surfaces of the contact plate 110.

(37) In this instance, the recess 111 may be configured such that a depth of the recess 111 changes as extending from rear to front sides of the contact plate 110. Accordingly, the recess 111 is formed the deepest at the contact portion between the movable contactor 200 and the fixed contactor with the greatest amount of heat generated, thereby minimizing the affection of the generated heat. Also, the depth of each recess 111 may be gradually reduced as getting away from the contact portion, thereby preventing the contact portion from being melted due to the heat as much as possible.

(38) In addition, the contact plate 110 and the insulating cage 100 may be made of different materials from each other.

(39) In this instance, the contact plate 110 may be made of a material with relatively higher heat-resistance than the insulating cage 100, to be prevented from being easily melted due to external heat.

(40) That is, the insulating cage 100 may be made of thermoplastic resin such as vinyl chloride resin, acrylic acid resin or poly acetyl resin or the like. The contact plate 110 may be made of thermosetting resin such as phenolic resin, poly ester resin or the like which has higher heat-resistance than the thermoplastic resin.

(41) The thermosetting resin is resin which does not change in shape even though heat is applied again after being molded by applying heat, and exhibits high thermal resistance, solvent resistance, chemical resistance, mechanical property, electric insulating property and the like.

(42) Therefore, the contact plate 110 may be molded by using the thermosetting resin having such properties, thereby being prevented from being melted due to heat.

(43) When molding the contact plate 110, a separate filler may be inserted to reinforce rigidity or other properties of the contact plate 110.

(44) Meanwhile, the insulating cage 100 may be molded by using the thermoplastic resin.

(45) Since the thermosetting resin does not return to a resin state even if heat is applied again after being molded, the contact plate 110 having a simple shape is molded by using the thermosetting resin to be prevented from being melted due to heat. On the other hand, the insulating cage 120 is molded by using the thermoplastic resin facilitated to be molded, such that a complicated shape of the insulating cage 120 can be well implemented without an error.

(46) If the insulating cage 100 is molded using the thermosetting resin, it cannot return to the resin state even though being wrongly molded. Defective products may be created accordingly, thereby drastically increasing fabricating costs.

(47) Furthermore, only the contact plate 110 which is located at a position where heat is mainly generated may be molded by using the thermosetting resin and the insulating cage 100 which is the other portion except for the contact plate 110 may be molded by using the thermoplastic resin through insert-molding. This may result in minimizing the use of the thermosetting resin which is impossible to be recycled and thus preventing in advance an occurrence of an environment-related problem, such as an environmental pollution, due to the thermosetting resin.

(48) When the insulating cage 100 is molded by using PA66 as the thermoplastic resin, the insulating cage 100 reacts with arc heat generated during a breaking operation of the air circuit breaker so as to discharge gas, which improves an arc-extinguishing performance, from the insulating cage 100, resulting in enhancing arc-extinguishing efficiency of the air circuit breaker.

(49) As such, by molding the contact plate 110 using the thermosetting resin, the melting due to heat can be prevented and the occurrence of the environmental problem can be prevented. Also, by molding the insulating cage 100 using the different thermoplastic resin, particularly, PA66, the arc-extinguishing efficiency can be improved. Consequently, by using the different materials upon molding the breaking part, the breaking part can simultaneously have the unique efficiencies belonging to the different materials

(50) In addition, the contact plate 110 and the insulating cage 100 may be made of a thermosetting resin composite and a thermoplastic resin composite, respectively.

(51) That is, the contact plate 110 and the insulating cage 100 may be made of thermosetting resin composite and thermoplastic resin composite containing glass fibers or carbon fibers. In this instance, the contact plate 110 can be prevented from being melted due to heat, become lighter and have improved durability.

(52) Also, the insulating cage 100 can be easily molded and have improved durability.

(53) Hereinafter, a method of fabricating the breaking part of the air circuit breaker in accordance with the one embodiment of the present invention will be described in detail, with reference to FIGS. 12 to 14.

(54) First, the contact plate 110 is molded by injecting thermosetting resin into a molding frame having a predetermined shape (S101).

(55) In this instance, the contact plate 110 may be provided with a plurality of contact plates, or be provided with a plurality of contact plates and a contact plate connection member 113 connecting the contact plates to the insulating cage 100.

(56) When the contact plate 110 is formed integrally with the contact plate connection member 113, the contact plate 110 and the contact plate connection member 113 are molded using the thermosetting resin. Afterwards, the insulating cage 100 is molded using the thermoplastic resin by inserting the molded contact plate 110 and contact plate connection member 113.

(57) When the breaking part is molded by constituting the contact plate 110 and the contact plate connection member 113, the total number of components to be used for finally producing the insulating cage 120 is two. Accordingly, an inserting operation of the contact plate 110 and the contact plate connection member 113 is facilitated and the entire structure is simplified.

(58) Also, after molding each contact plate 110 by inserting the thermosetting resin into the molding frame, an insulating cage 100 with the plurality of contact plates 110 therein is molded using the molded contact plates 110 by inserting the molded contact plates 110.

(59) When the breaking part is molded only by constituting the plurality of contact plates 110 without the contact plate connection member 113, a number of an operation increases but production efficiency of the contact plates 110 is remarkably improved.

(60) According to the present invention having such configuration and operations, the recess 111 may be formed on one side or each of both sides of each contact plate 110 provided in the insulating cage 100 so as to reduce the contact area between the movable contactor 200 and the contact plate 110 when the movable contactor 200 and the contact plate 110 are brought into contact with each other. Accordingly, the contact portion between the movable contactor 200 and the contact plate 110 can be prevented from being melded due to heat generated at the contact portion while a current flows along the contact portion in a state that a fault current has been introduced.

(61) Also, the recess 111 may be located adjacent to the contact portion between the movable contact 210 of the movable contactor 200 and the fixed contact of the fixed contactor, so as to be located at a portion where the greatest amount of heat is generated upon an introduction of a fault current, thereby minimizing an affection of the heat generated at the contact portion to the contact portion between the movable contactor 200 and the contact plate 110.

(62) The recess 111 may be inclined inward the contact plate 110 from rear to front sides of the contact plate 110 so as to increase the inward depth as getting close to the position where the movable contact 210 of the movable contactor 200 and the fixed contact of the fixed contactor are brought into contact with each other, thereby minimizing the affection due to the generated heat.

(63) The contact plate 110 may be made of the thermosetting resin so as to be prevented from being melted due to the heat generated around the contact portion upon the introduction of the fault current.

(64) Since the contact plate 110 can be prevented from being melted, it is possible to prevent a failure of a rotation of the movable contactor 200 due to the movable contactor 200 being fused on the contact plate 110, caused by the melted contact plate 110.

(65) Also, upon the fabrication of the breaking part, the contact plate 110 made of the thermosetting resin may first be molded and the insulating cage 100 made of the thermoplastic resin may finally be molded, thereby facilitating the insertion operation of the contact plate 110.

(66) 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.