KR950009746Y1 - Circuit breaker with arc chamber vent - Google Patents

Abstract

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Description

Circuit breaker with arc chamber vent

1 is a longitudinal cross-sectional view of a circuit breaker

FIG. 2 is a cross sectional view taken along the line II-II of FIG. 1

3 is a partial cross-sectional view of a conventional exhaust structure

4 is a partial cross-sectional view of the exhaust structure of the present invention.

5 and 6 are partial sectional elevational views of the exhaust structure embodying the present invention.

7 is a longitudinal cross-sectional view taken along the line VII-VII of FIG.

* Explanation of symbols for the main parts of the drawings

10: circuit breaker 12: base

14 cover 22 operating mechanism

86: tubular insulation member 92: terminal screw

The present invention relates to an electrical circuit breaker, and more particularly to a circuit breaker having a line terminal shield (shield). Conventionally, there has always been some problem in controlling the discharge of arc gas generated in circuit breakers during contact disconnection caused by overload.

This problem is relatively small but has a high current blocking rating and a metallic enclosure in which the wiring terminal is placed close to the arc gas vent of the breaker and the ionized arc gas flowing out of the arc gas vent is mounted inside the terminal of the circuit breaker and the circuit breaker. This is particularly acute in wiring circuit breakers that can cause voltage breakdown between the boxes. This kind of voltage discharge can develop into a ground fault, and if it becomes severe, it can cause an inter-phase fault outside the circuit breaker.

The main purpose of the present invention is to overcome the above problems, and the present invention provides an electrical connection in series between the insulated housing and the line terminal, the load terminal, and the line terminal and the load terminal, which are supported inside the leading edge housing. At least one pole unit having a pair of contacts, and an actuation mechanism for opening and closing the contacts, wherein the contacts are disposed in an area close to the line terminal in the housing, the housing being the line terminals. An end wall including a wall portion having an arc gas vent formed therethrough to separate the line terminal from an area close to and through the position proximate a portion of the line terminal, the line terminal having an arc flowing out of the vent. One of the line terminals to be shielded from contact with the gas Provided is a circuit breaker associated with a tubular member surrounding the portion.

The tubular member, which extends to fit the line terminal on the inner surface of the housing and onto a portion of the line terminal, substantially diverts the exhaust arc gas around the line terminal portion, thereby opposing the surface portion of the housing end wall and its opposite surface. The divorced arc gas that is exhausted flows around the line terminal portion without contacting the line terminal portion and is not flowed back into the enclosure containing the circuit breaker without contacting the line terminal portion. The tubular member is in direct communication with a through hole formed in the housing wall, the distal end of which is inclined or tapered toward the downstream of the arc gas outlet passage, so that the tubular member is The exhaust arc gas passing through the inclined end forms a low pressure region, thereby And allowed to mix with the cold air is absorbed ionized arc gas, and cooling the ionized arc gas accordingly good to thereby decrease the conductivity. The tubular member is preferably formed integrally with the cover of the insulating housing.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention. The circuit breaker 10 shown in FIG. 1 comprises a molded electrically insulated housing, which is in contact with the base 12 along the base 12 and along a line 16 such as a screw (not shown). The circuit breaker shown is comprised of a three pole circuit breaker having three pole units, each pole unit having a line terminal 18, a load terminal 20, one Is connected to the line terminal 18 via a conductor 19 and the other one when the contacts are separated by a load and a pair of contacts 30, 32 arranged on the movable contact arm 28. , Arc extinguishing device or arc chute 72 for extinguishing electric arc 70 generated between 32 and tripping device for tripping the opening of the circuit breaker in response to a predetermined overcurrent generated in the associated pole unit. Includes 24 poles of each uni The contact arm 28 at is connected to the load terminal 20 via a flexible conductor 36, a bimetal element 38 (which forms part of the tripping device 24 of the associated pole unit) and the conductor 40. And pivotally supported at one point 42 of the weeder arm attachment portion 44 of the insulated crossbar 26, the crossbar 26 being capable of rotational movement about the longitudinal axis of the crossbar. Is optionally supported). The circuit breaker 10 is common to all pole units and is disposed between the two support plates 45 (only one of which is shown in FIG. 1) fixed to the base 12 and disposed in the central pole unit. And an actuation mechanism 22 supported by 45. The actuation mechanism 22 is a release member or cradle member 56 pivotally supported by the support plate 45 by pins 58, and a point; Pivotally connected to the cradle member 56 at 62 and pivotally by nipin means 60 to form a toggle linkage pivotally connected to a crossbar portion 44 coupled to a central pole unit at point 42. It includes a pair of toggle links 52 and 54 connected together. The actuation mechanism 22 further comprises an actuating lever 46 of approximately inverted U shape, the actuating lever being pivotally supported at an approximately U-shaped notch 48 formed in each support plate 45. It has two legs with a bent and a bright portion to which the insulating manual operation handle 50 extending through the opening of the cover 14 is fixed. The overcenter moving spring 64 is formed with the curved portion of the actuating lever 46. A tension force is connected between the needle pins 60 of the toggling packages 52 and 54 so as to act. The cradle member 56 straightens the toggling packages 52 and 54 so that the contact arm 28 moves from the contact opening position to the contact closure position (the position shown by the one-point makeover 28a in FIG. 1). Although shown in FIG. 1 in an unaffected position, the cradle member can be releasably latched in a "reset" condition that closes the contacts 30, 32 through manipulation of the handle 50. The latch surface 68 on the 56 is coupled to the latch 66 coupled in a known manner. When an overload or abnormal current occurs in one of the pole units, the associated trip device 24 responds and actuates through the trip bar 47 common to all pole units, causing the latch lever 66 to cradle. To release (56). Accordingly, the toggling packages 52 and 54 are folded by the operation of the overcenter spring 64 so that the contact opening movement of the crossbar 26 is executed. Such operations are well known in the prior art (eg, US Pat. Nos. 4,503,408 and 4,220,935). From FIG. 1 each contact arm 28 is supported by the crossbar 44 in such a way that it is electrodynamically driven to the contact open position independent of the crossbar at a current limiting rate when an abnormal current or short circuit current greater than a predetermined level occurs. It is understood that such an operation is described in EPC Patent Publication No. 0,145,990.

As mentioned above, and as is known in the art, when the contacts 30, 32 are automatically opened manually or under load, the electric arc 70 formed between the contacts is an arc chute. Aspirated by 72, further elongated, crushed, and extinguished. These arcs are formed by the generation of arc byproducts in the form of ionized gas, which increase the strength of these arc byproducts which must be properly vented to prevent structural damage or breakage of the circuit breaker. As a result, the arc chute 72 has a through hole 76 formed in the end wall 74 thereof, and the constant end wall 74 opens the inside of the housing from an end cavity containing the line terminal 18. The housing end wall is disposed adjacent to the housing end wall of the circuit breaker to be separated, and the housing end wall is provided in each pole unit together with a vent 78 formed in the end wall which is a part of the housing cover. Referring to FIG. 3 showing a conventional structure for evacuating the arc gas, it can be seen that the arc gas is exhausted in the direction of the arrow 82 through the cavity 94 formed in the conventional circuit breaker housing cover 15. . Within the cavity 94 a line terminal screw 92 of the associated pole unit is extended, which terminal screw can be easily inserted by a screw driver (not shown) or the like which can be inserted through an opening formed in the front wall of the cover 15. Can be assembled. In this conventional construction, the terminal screw 92 is exposed to the exhaust ionization gas and a portion of the ionization gas flows into a metallic receptacle (not shown) that surrounds the circuit breaker through the screw insertion opening of the cover 15. Goes. As a result, voltage discharge may occur between the line terminal including the terminal screw 92 and the metal portion of the line terminal and / or receptacle of adjacent pole units. This problem can be mitigated by providing a means for shielding and separating each terminal screw from direct contact with the exhaust ionization gas. In particular, referring to FIGS. 1, 2 and 4, it can be seen that the cover 14 has a tubular insulating member 86 for each pole unit. The tubular insulation member 86 is arranged in the outflow passage of the arc gas discharged from the cover toward the associated terminal screw 92 and at least from each vent 78 formed in the end wall 80 of the cover 14. It extends in such a way that it is inserted into the image. As best seen in FIG. 2, each tubular insulating member 86 forms a pair of outlet passages 84 with the adjacent surface portion of the cover end wall 90. The outlet passage 84 begins in the vent 78 and extends to both sides of the tubular member 86 to an outlet 88 formed in the cover end wall and communicating with the atmosphere. Thus, the arc gases passing through each of the vent holes 78 are discharged in the direction of the arrow 82 through the outlet passage 84 and the discharge port 88 without contacting the terminal screw 92, and the terminal screw is a tubular insulating member. Covered by 86 and protected. Furthermore, each tubular member 86 shown in this preferred embodiment is ionized to the metallic receptacle housing circuit breaker in use because it is molded integrally with the cover 14 and extends along the axial direction of the screw insertion opening 87, for example. This allows the screwdriver to access the terminal screw 92 without providing a passage for the gas to enter.

Each tubular member 86 of FIGS. 5, 6 and 7 is inclined cross section 98 (see FIG. 5) downstream of the gas outlet passage, ie away from the associated vent 78. And an inclined end (ie, a free end) to provide a tubular insulation member 86 having an < RTI ID = 0.0 > Therefore, the tubular insulation member 86 continues to shield the terminal screw 92 so that it does not come into contact with the ionized arc gas flowing out of the vent 78 and at the same time causes the exhaust arc gas to pass through the inclined end of the tubular member at a low pressure. A region is created to suck cold air from the ridge through the tubular member 86 and mix with the ionizing arc gas, as indicated by the arrows in FIGS. 5 and 7, thereby cooling the ionizing arc gas and reducing its conductivity. .

Claims (6)

At least one pole unit having an insulated housing and a pair of contacts 30, 37 disposed in the line terminal 18, the load terminal 20 and the arc chamber 72 and connected in series between the line terminal and the load terminal. And an actuating mechanism 22 for opening and closing the contact, wherein the housing separates the line jar from the arc chamber and is in close proximity to the portion 92 of the line terminal. In a circuit breaker having an end wall comprising a wall portion 80 formed by The line terminal 18 is coupled to a tubular member 86 surrounding the portion 92 of the line terminal to be shielded from contact with the arc gas flowing out of the vent 78, the tubular member being connected to the housing. Extends into the outflow passage of the arc gas flowing out from the vent 78 in communication with the opening 87 formed in the end wall of the wall, and when the arc gas flows in the outflow passage, ambient air is sucked through the opening 87 and the arc A circuit breaker having an end portion (98, 102) inclined towards the downstream of the outlet passage to mix with the gas. The method of claim 1, And the tubular member (86) extends from the inner surface of the housing toward the line terminal (18, 92) and to be fitted over a portion (92) of the line terminal. The method according to claim 1 or 2, A portion 92 of the line terminal 18 is a terminal screw 92 and the opening 87 and the tubular member 86 are configured such that the terminal screw is inserted through the opening 87 and the tubular member. Circuit breaker, characterized in that it is axially aligned with respect to the terminal screw so that it can be assembled by a mechanism. The method according to claim 1 or 2, The tubular member (86) formed integrally with the insulating housing. The method according to claim 1 or 2, The insulating housing comprises a cover (14) having an inner surface on which the tubular member (86) extends, wherein the tubular member (86) is integrally formed with the cover (14). 3. The tubular member (86) according to any one of the preceding claims, wherein the tubular member (86) forms two gas outlet passageways (84) together with adjacent surface portions of the end wall (90), wherein the outlet passages are the vents (78). And the tubular member is rotated on both sides thereof and extends to an outlet (88) formed in the end wall and communicating with the outside.