CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and claims the benefit of U.S.

Patent Application Serial No. 14/288,424, filed May 28, 2014, which is incorporated bv reference herein.

BACKGROUND

Field

The disclosed concept pertains generally to electrical switching apparatus. The disclosed concept also pertains to arc chute assemblies for electrical switching apparatus. The disclosed concept further relates to barrier .members for arc chute assemblies.

Background hiforaiation

Electrical switching apparatus, such as circuit breakers, provide protection for electrical systems from electrical fault conditions such as. for example, current overloads, short circuits, and abnormal level voltage conditions.

Circuit breakers, for example, typically include set of stationar electrical contacts and a set of mo vable elec trical contacts. The stationary and movable electrical contacts are in physical and electrical contact with one another when it is desired that the circuit breaker energize a power circuit. When it. is desired to interrupt the power circuit, the movable contacts and stationary contacts are separated. Upon initial separation of the movable contacts away from the stationary contacts, an electrical arc is formed in the space between the contacts. The arc provides a means for smoothly transitioning from a closed circuit to an open circuit, but produces a number of challenges to the circuit breaker designer. Anions them is the fact that the arc results in the undesirable flow of electrical current through the circuit breaker to the load. Additionally, the arc, which extends between the contacts, often results in vaporization or sublimation of the contact material itself. Therefore, it is desirable to extinguish any such arcs as soon as possible upon their propagation.

To facilitate this process, circuit breakers typically include arc chute assemblies which are structured to attract and break-up the arcs. Specifically, the movable contacts of the circuit breaker are mounted on arms thai are contained in a pivoting assembly which pivots the movable contacts past or through arc chutes as they move into and out of electri cal contact with the stationary contacts. Each arc chute includes a plurality of spaced apart arc plates mounted in a wrapper. As the movable contact is moved away from the stationary contact, the movable contact moves past the ends of the arc plates, with the arc being magnetically drawn toward and between the arc plates. The arc plates are electrically insulated from one another such that the arc is broken-up and extinguished by the arc plaies.

Additionally, along with the generation of the arc itself, ionized gases, which can cause excessive heat and additional arcing and, therefore, harm to electrical components, are formed as a byproduct of the arcing event. The ionized gases can undesirably cause the arc to bypass a number of intermediate arc plates as it moves through the arc chute. This reduces the number of arc voltage drops and the effectiveness of the arc chute. It also creates current and gas flow patterns that tend to collapse groups of arc plates together, further reducing the voltage divisions in the arc chute and its cooling effectiveness. Additionally, debris, such as, for example, molten metal particles, are created during the arcing event and can collect in the gaps between arc plates, causing an electrical short, and high current levels during current interruption generate high magnetic forces, which attract the arc plates together.

There is thus room for improvement in electrical switching apparatus, and in arc chute assemblies and barrier members therefor.

SUMMARY

These needs and others are met by embodiments of the disclosed concept wherein a barrier member is provided which amon other benefits, controls the flow of ionized gases in an arc chute assembly of an electrical switching apparatus.

In accordance with one aspect of the disclosed concept, a barrier member for an arc chute assembly of an electrical switching apparatus is provided. The arc chute assembly comprises a first sidewall, a second sidewall opposite and spaced apart from the first sidewall, and a plurality of arc plates disposed between the first sidewall and the second sidewall. The arc chute assembly is structured to be disposed in the electrical switching apparatus. The electrical switching apparatus comprises a housing and a pair of separable contacts enclosed by the housing. The contacts are structured to trip open. An arc and ionized gases are generated in response to the contacts tripping open. The barrier member comprises a body portion structured to be disposed between the first sidewail and the second sidewail, the body portion comprising a first support portion, a second support portion, and a cover portion connecting the first support portion to the second support portion; a first containment portion extending from the first support portion, the first containment portion being structured to be disposed proximate the first sidewail; and a second containment portion extending from the second support portion toward the first containment portion, the second containment portion being structured to be disposed proximate the second sidewail. The second containment portion is spaced from the first containment portion.

As another aspect of the disclosed concept, an arc chute assembly for an electrical switching apparatus is provided. The electrical switching apparatus includes a housing and a pair of separable contacts enclosed by the housing. The separable contacts are structured to trip open. An arc and ionized gases are generated in response to the separable contacts tripping open. The arc chute assembly comprises a plurality of retaining components comprising a first sidewail and a second sidewail opposite and spaced apart from the first sidewail; a plurality of arc plates disposed between the first sidewail and the second sidewail; and a barrier member comprising: a body portion disposed between the first sidewail and the second sidewail, the bod portion comprising a first support portion, & second support portion, and a cover portion connecting the first support portion to the second support. portion; a first containment portion extending from the first support portion, the first containment portion being disposed proximate the first sidewail; and a second containment portion extending from the second support portion toward the first containment portion, the second containment portion being disposed proximate the second sidewail. The second containment portion is spaced from the first

containment portion.

As another aspect of the disclosed concept, an electrical switching apparatus comprises a housing; separable contacts enclosed by the housing; an

-3- operating mechanism structured to open and close the separable contacts and to trip open the separable contacts in response to an electrical fault; and at least one arc chute assembly disposed at or about the separable contacts in order to attract and dissipate an arc and ionized gases whic are generated by the separable contacts trippmg open in response to the electrical fault, the at least one arc chute assembly comprising: a pl uralit of retaining components comprising a first sidewaii and a second sidewaii opposite and spaced apart from the first sidewaii; a plurality of arc plates disposed between the first sidewaii and the second sidewaii; and a barrier member comprising', a body portion disposed between the first sidewaii and the second sidewaii, the body portion comprising a first support portion, a second support portion, and a cover portion connecting the first support portion to the second support portion; a first containment portion extending from the first support portion, the first containment portion being disposed proximate the first sidewaii; and a second containment portion extending from the second support portion toward the first containment portion, the second containment portion being disposed proximate the second sidewaii. The second containment portion is spaced from the first containment portion.

BRIEF DESCRIPTION OP THE DRAWINGS

A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:

Figure 1 A is an isometric view of an electrical switching apparatus, and arc chute assembly and barrier member therefor, in accordance with an embodiment of the disclosed concept, shown in the closed position with a portion of the housing cutaway to show hidden structures;

Figure 1 B is an enlarged isometric view of a portion of the electrical switching, and arc chute assembly and barrier member therefor of Figure 1A;

Figure 2 A is an isometric view of the electrical switching apparatus, and arc ch ute assembly and barrier member therefor of Fiaure 1 A, modified to sho w the electrical switching apparatus in the open position;

Figure 2B is an enlarged isometric view of a portion of the electrical switching apparatus, and arc chute assembly and barrier member therefor of Figure 2 A;

-4- Figure 3 A is an isometric view of the arc chute assembly of Figure 2B;

Figure 3 B is an exploded isometric view of the arc chute assembl y of

Figure 3 A;

Figures 4 A and 48 are isometric views of the barrier member for the arc chute assembly of Figure 3B; and

Figure 5 is an isometric view of a pair of barrier members fo the arc chute assembly of Figure 3B. each shown prior to being completely formed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, directional phrases used herein such as, for example, "top", "bottom", "front", "back , "behind", "side", "tight", "left", "upper", "lower", and derivatives thereof shall relate to the disclosed concept, as it is oriented in the drawings. It is to be understood thai the specific elements illustrated in the drawings and described in the following specification are simply exemplary embodiments of the disclosed concept. Therefore, specific orientations and other physical characteristics related to the embodiments disclosed herei n are not to be considered limiting with respect to the scope of the disclosed concept.

As employed herein, the term "number" shall mean one or a integer greater than one {i.e.., a plurality).

As employed herein, the statement that two or more parts are

"connected" or "coupled" together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.

As employed herein, die statement that two or more parts or components "engage" one another shall mean that the parts touch and/or exert a force against one another either directly or through one or more intermediate parts or components.

Figure .1 A shows an electrical switching apparatus (e.g., without limitation, mining circuit breaker 2) in a closed position. The circuit breaker 2 includes a housing 4, an operating mechanism 6 (shown in simplified form), a stationary contact. 8, a contact arm , and a movable contact 10 connected to the contact arm 9, The housing 4 encloses the operating mechanism 6, the contacts 8,10,

-5- and the contact arm 9. in operation, the operating mechanism 6 trips the contact arm 9 in response to an electrical fault condition, thus mo ving the movable contact 10 from the closed position, in which it engages the stationary contact 8, to an open position (Figure 2 A and Figure 2Bh in which the movable contact 10 is spaced from the stationary contact 8. As the movable contact 10 moves from the closed position to the open position, an arc flash event occurs due to the separation between the movable contact 10 and the stationary contact 8. Additionally, ionized gases are formed as a byproduct of the arcing event. I order to attract and dissipate the arc and ionized gases generated by the tripping of the contacts 8,10, and control the arc flash flow direction of the ionized gases, the circuit breaker 2 includes an arc chute assembly 1 0 near the contac ts 8,10.

The example circuit breaker 2 shown and described herein is a multiple pole circuit breaker 2, It will be appreciated that the circuit breaker 2 may employ any number of arc chute assemblies for each of the poles of the circuit breaker 2. Additionally, although the disclosed concept is being described in association with the multiple pole circuit breaker 2. it will be appreciated that a single pole circuit breaker (not shown) may employ an arc chute assembly (not shown) in accordance with the disclosed concept in similar manner as described herein, to control the arc flash flow- direction of ionized gases given off daring an arcing event.

Referring to Figure 3 A and Figure 38, the arc chute assembly 100 includes a plurality of retaining components (e.g. , without limitation, opposing and spaced apart side-walls 102, 104, and base 106 extending between the sidewalls 102,104). The arc chute assembly 1 0 further includes a plurality of arc plates (two arc plates 108, 1 12 are indicated) and a barrier member Ϊ 0, each being located between the sidewalls 102,104. The barrier member 150 is preferably press fit between the sidewalls 102, 104, advantageously allowing for a secure connection with the sidewalls 1 2,1 4, without requiring an additional separate fastening mechanism, means or method.

It is. however., also within the scope of the disclosed concept for the barrier member 150 to engage the sidewalls J 02, j 04 in a manner other than being press fit. For example, and without limitation, the barrier member 150 may be slot connected with the first sidewall 102 and/or slot connected with the second side-wall

-6- 104 (see, e.g., slot 103 schematically shown in simplified form extending along the top of the first sidewaii 1.02 in Figure 3B). It is within the scope of the disclosed concept for the barrier member 150 to have a protrusion (not shown) that extends into the slot 103. thereby allowing for a relatively strong connection. In operation, as ionized gases given off from the tripping of the contacts 8,10 engage the barrier member 150, such a strong connec tion between the barrier member 50 and tire sidewalis 102,104, be it by a press fit connection, by a slot connection or any other suitable secure engagement, advantageously enables the barrier member .150 to remain secure within the arc chute assembly 100.

The barrier member 150 includes a body portio 152 and pair of containment portions (e.g., without limitation, elongated flaps 154,156). The body portion .152 includes a pair of support portions 158,160 and a cover portion 162 connecting the first support portion 1 8 to the second support portion 160. live first elongated flap 154 extends from the first support portion 158 and is located near the first sidewaii 102. The second elongated flap 156 extends from the second support portion 160 and is located near the second sidewaii 104. Furthermore, the second elongated flap 156 extends toward the first elongated flap Ϊ 54 and is spaced from the first elongated flap 154. In operation, as ionized gases given off during an arc flash event flow throughout the arc chute assembly 100, the elongated flaps 154, 156 create a self-sealinu effect, hi other words, and with reference to Fioure 2B, after the ionized gases reach the sidewalis 102,104, the elongated flaps 154,156 block the ionized gases, thus preventing them f om re-striking the contact arm 9, This minimizes contact degradation and prevents dielectric breakdown, advantageously allowing for higher interruption capability of the circuit breaker 2.

Referring to Figure 3B, the arc plate 108 includes an edge 109 that engages the sidewaii 102, and an edge 1 0 extending t herefrom toward the base 106 in a direction 1 10 ^* . The arc plate 1 12 similarly includes an edge (not shown) that engages the sidewaii 104 and an edge 1 14 extending therefrom toward the base 106 in a direction 1 1 '. The directions 1 10', 14' are each preferably at an angle with respect to the corresponding sidewaii 102,104 of betwee 30 degrees and 60 degrees, and more preferably between 40 degrees and 50 degrees. Additionally, the first elongated flap 154 of the barrier member 150 extends f om the first support portion 158 i a

.7. direction 154' substantially parallel to the direction 1 10'. likewise, the second elongated flap 156 extends from the second support portion 160 in a direction 156' subsiaiitiaily parallel to the direction 1 14 ^! , As seen in Figure 3 A, the edge 1 10 of the arc plate 108 is substantia! ly located between the first elongated flap 154 and the first sidewall 102. Similarly, the edge 114 of the arc plate 12 is substantially located betwee die second elongated flap 156 and the second sidewall 104.

In operation, this configuration of the arc plates 108,1 12 and the elongated flaps 1 4,156 further creates the self-sealing effect. More specifically, ionized gases given off by the tripping of the contacts 8, 10 (Figure 1 A through Figure 28) located near the edge 1 10 of the arc plate 1 OS will advantageously be contained betwee the first elongated flap 154 and the fi st sidewall 102, thereb avoiding re- striking to the contact arm 9. For example, the first elongated flap 154 may engage the edge 1 10 of the arc plate 108, thereby completely sealing a potential pathway for ionized gases, which would otherwise re-strike the contact arm 9. Similarly, ionized gases located near t e arc plate 1 12 will advantageously be contained between the second elongated flap 156 and the second sidewall 104, thereby avoiding re-striking the contact arm 9.

As seen in Figure 3A, the first sidewall 102 is located in a plane 102' and the second sidewall 104 is located in a plane 104 ^! . Additionally, the cover portion 162 is located in a plane 162' and the support portions 158.1 0 are located in a plane 159 (e.g., the first support portion 158 is coplanar with the second support portion 160), The planes 159,162' are each normal to the planes 102 ^, ,i04 ^t of the side-walls 102,104. Such a configuration advantageousl allows for a relatively secure connection betwee the barrier member 150 and the sidewalk 102, 104.

Additionally, the cover portion 1 2 includes number of elongated portions 166,168 J 70. The first elongated portion 166 extends from the first support portion 158 and the second elongated portion 168 extends from the second support portion 160. The third elongated portion 170 connects the first elongated portio 166 to the second elongated portion 168 and is normal to each of the first elongated portion 166 and the second elongated portion 168. Furthermore, the third elongated portion 170 is elongated in a direction norma! to the planes 1 2' J 04'. By having generally parallel opposing sides (e.g., the first support portion 158 and the first

-8- elongated portion 166 are generally parallel with respect to the second support portion 160 and the second elongated portion 168), and by ^' having the elongated flaps 154 J 56, the support portions 158, 1 0, and the cover portion 1 2 be planar, manufacturing of the barrier member 150 is advantageously simplified. For example and without limitation, a flat unitary piece of metal (not shown) can be die cut and simply bent into the desired shape, as shown for example and without limitation, in Figures 4A - 5.

Furthermore, although the disclosed concept has been described in association with the cover portion 162 including the elongated portions 166, 168,170, it is within the scope of the disclosed concept for the cover portion 162 to incl ude other configurations (e.g., without limitation, a generally continuous square shaped cover portion (not shown}). Additionally, although the disclosed concept has been, described in association with the planar elongated flaps 154, 156, it is within the scope of the disclosed concept, t employ alternative Ha s (not shown). For example and without limitation, it is within the scope of the disclosed concept to emplo flaps (not shown) in an arc chute assembly (not shown) that are concave towards the sidewalls 102,104. Moreover, it is within the scope of the disclosed concept to employ elongated flaps (not shown) in an arc chute assembly (not shown) with roughened or corrugated surfaces.

Referring to Figure 4A, there is an angle 155 between the first support portion 158 and the first elongated flap 154. Likewise, there is an angle 157 between the second support portion 160 and the second elongated fl p 156. The angles 155,1.57 are preferably between 120 degrees and IS degrees, and more preferably being between 130 degrees and 140 degrees. The sel f-sealing effect of the ionized gases is optimized by orienting the elongated flaps 154,156 as such with respect to the support portions 158,160.

Furthermore, the first elongated portion 166 includes an end surface 1 2 that extends from the first support portion 158 at an angle 172'. Likewise, the second elongated portion: 168 includes an end surface 174 that extends from the second support portion 160 at an angle 174'. The angles 172', 174', like the angles 155,157, are preferably between 120 degrees and 150 degrees, and more preferably being between 130 degrees and 140 degrees, in this manner, the elongated flaps

.9. 154,156 are advantageously able to extend inwardly toward the base 106 (Figure 3 A. and Figure 3B) all the way to ihe end surfaces 172,174 of the cove portion 162, This further improves the self-sealing effect, as the ionized gases will be prevented from traveling from the sidewalls 102, 104 to the contact arm 9 by way of an opening proximate the end surfaces 172, 174.

As seen in Figure 4A, the cover portion 162 is at an angle 164 with respect to plane 159 of the support portions 158,160. The angle 1 4 is preferably between 75 degrees and 105 degrees. As a result, the cover portion 162 substantially extends over and covers the arc plates 108, 112 (Figure 3A and Figure 3B), advantageously aiding in preventing ionized gases given off from tripping of the contacts 8,10 (Figures 1A through 2B) from exiting the top of the arc chute assembly 100 and into the circuit breaker 2.

Fkure 5 shows an isometric view of a barrier member 250, shown prior to being fully formed. As seen, the barrier member 250 includes a pair of support portions 258,260 and a cover portion 262. During manufacturing, the cover portion 262 is bent toward the support portions 258,260 to be brought into final shape (see, e.g., barrier member ISO of Figures 3B, 4 A and 4B). Figure 5 also shows another barrier raernber 250 ^* that has not been fully formed. In this state, the barrier members 250,250' are able to be nested with one another. Thus, shipping is advantageously simplified and costs saved as the barrier members 250,250' are able to be more efficiently stacked with one another.

Referring again to Figure I B, the first elongated flap 154 is elongated in a direction 154" and the second elongated flap 156 is elongated in a directio 1 6". As the movable contact 10 moves f om the closed position (Figure Ϊ B) to the open position (Figure 2B), the movable contact 10 moves toward the cover portion 162 in a direction 12 ( Figure 2B) parallel to the directions 154".156". As the movable contact 1 moves from the open position to the closed position, the movable contact 10 moves away from the cover portion 1.62. Additionally, each of the contacts 8,10 is located between the elongated flaps 154,156. Accordingly, it will be appreciated that the disclosed concept advantageously results in a more controlled flow of ionized gases given off by the tripping of the contacts 8, 10 throughout the arc chute assembly 100. Whil e specific embodiments of the di sclosed concept have been described in detail, it will be appreciated b those skilled in the art that various modifjcations and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosed concept which is to be gi ven the full breadth of the c laitns appended and any and all equivalents thereof.

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