Patent Application
20140131317
1. Field
The disclosed and claimed concept relates generally to circuit interrupters and, more particularly, to an arc runner assembly for use in a circuit interrupter, as well as to a circuit interrupter.
2. Related Art
Circuit interrupters are known for use in numerous applications. Circuit interrupters are employed, for example, to open a portion of a protected circuit in certain predefined circumstances, such as might include predefined overcurrent and under-voltage circumstances, as well as other circumstances.
As is generally understood in the relevant art, a circuit interrupter typically includes a set of separable contacts that are electrically interposed between line and load conductors, and the separable contacts can be separated from one another in order to open the portion of the protected circuit to which the line and load conductors are connected. Since an electrical arc is typically formed between the contacts during their initial separation, and since such an electrical arc can be destructive to the circuit interrupter and to the protected circuit, such electrical arcs are desirably extinguished as soon as possible, and circuit interrupters typically employ some type of apparatus or system to extinguish such arcs. One type of arc extinction system includes an arc chute that includes a plurality of arc plates that are divergently oriented and which are configured to break up and extinguish an arc. An arc runner typically is employed adjacent a stationary contact of the set of separable contacts to direct the arc toward the arc chute. Any of a wide variety of devices can be employed to help move the arc in the direction of the arc chute, and these can include devices that generate magnetic fields which push the arc toward the arc chute, devices that generate gases in the presence of an arc that push the arc toward the arc chute, and the like.
While such arc extinction systems have been generally effective for their intended purposes, they have not been without limitation. For example, many of the known arc extinction systems have been developed for use in AC applications wherein an arc often lasts for at most only one-half of a cycle. Such arc extinction systems are typically not directly applicable to DC applications since a DC arc can exist for longer period of time. Moreover, whereas the voltage in AC varies between positive and negative according to a known cycle, DC is typically either positive or negative and, depending upon the application, a protected DC circuit may at different times experience either positive voltage or negative voltage. A circuit interrupter that is intended to protect a DC circuit therefore desirably has the capability to interrupt both positive DC and negative DC at given current level in. Furthermore, certain applications such as photovoltaic applications have required successively greater and greater current interruption capabilities. It thus would be desirable to provide solutions that address such shortcomings in the art.
An improved arc runner assembly for use in a circuit interrupter provides a pair of arc runners that are situated at opposite sides of a stationary contact of the circuit interrupter. If used in a DC application, the arc runner assembly is configured to communicate a positive DC arc along one of the arc runners in a first direction away from the stationary contact and is further configured to communicate a negative DC arc along the other arc runner in another direction away from the stationary contact. The arc runner assembly additionally includes a support that is electrically engaged with a conductor of the circuit interrupter on a surface opposite that on which the stationary contact is disposed. The improved arc runner assembly advantageously facilitates extinction of electrical arc and extinguishes both positive and negative DC arcs in a DC application.
Accordingly, an aspect of the disclosed and claimed concept is to provide an improved arc runner assembly for use in a circuit interrupter to extinguish electrical arcs.
Another aspect of the disclosed and claimed concept is to provide an improved arc runner assembly which, if used in a DC application, extinguishes both positive and negative DC arcs.
Another aspect of the disclosed and claimed concept is to provide an improved circuit interrupter that employs such an arc runner assembly.
These and other aspects of the disclosed and claimed concept are provided by an improved arc runner assembly that is structured for use in a circuit interrupter having a first conductor, a second conductor, and a set of separable contacts electrically interposed between the first conductor and the second conductor. The set of separable contacts include a stationary contact situated on one of the first conductor and the second conductor. The arc runner assembly can be generally stated as including a first arc runner and a second arc runner, with the first and second arc runners are spaced apart from one another. The first arc runner is structured to be situated adjacent a first side of the stationary contact and to communicate an electrical arc away from the stationary contact in a first direction. The second arc runner is structured to be situated adjacent a second side of the stationary contact opposite the first side and to communicate an electrical arc away from the stationary contact in a second direction different than the first direction
A further understanding of the disclosed and claimed concept can be gained from the following Description when read in conjunction with the accompanying drawings in which:
An improved arc runner assembly 2 is depicted generally in
The circuit interrupter 4 can be said to include a first conductor 6, a second conductor 8, and a set of separable contacts 10 that are electrically interposed between the first and second conductors 6 and 8. One of the first conductor 6 and the second conductor 8 will typically be considered a line conductor, and the other of the first and second conductors 6 and 8 will typically be considered a load conductor, although the specific designation is not important herein. The set of separable contacts 10 in the depicted exemplary embodiment include a stationary contact 12 that is depicted as being situated on the first conductor 6. The set of separable contacts 10 further include a movable contact 14 that is situated on a movable contact arm 18 and that is electrically engageable with an engagement surface 16 of the stationary contact 12.
The circuit interrupter 4 further includes an arc extinction apparatus 20 that includes a set of arc plates (collectively indicated at the numeral 22), a first magnet 24, a second magnet 26, and a brace 28. The first and second magnets 24 and 26 are rare earth permanent magnets having their south poles facing toward one another and are held in place by the steel brace 28. The first and second magnets 24 and 26 could alternatively have their north poles facing toward one another without departing from the present concept. It is also expressly noted that the first and second magnets 24 and 26 could be of any form, i.e., whether or not permanent magnets, whether or not formed of rare earth materials or other materials, etc., without departing from the present concept. The arc extinction apparatus 20 further includes an intermediate element 30 that extends midway through the set of arc plates 22 and that includes a steel guide element 32 (
As is depicted generally in
It is noted, however, that in other embodiments of the arc runner assembly 2, the mounting hole 44 can accommodate other types of fasteners without departing from the present concept.
The first arc runner 36 can be said to include a first arc runner element 48 situated on a first leg 50. The first leg 50 supports the first arc runner element 48 in a position spaced from the base 42. The second arc runner 38 likewise can be said to include a second arc runner element 52 situated on a second leg 54, with the second leg 54 supporting the second arc runner element 52 in a position spaced from the base 42. The support 40 can be said to include a support element 56 situated on a strut 58, with the strut 58 supporting the support element 56 at a position spaced from the base 42. The first and second arc runners 36 and 38 can be said to be situated on opposite sides of the support 40, and the support 40 can alternatively be said to be situated generally between the first and second arc runners 36 and 38.
The first arc runner element 48 includes a generally planar first arc runner surface 60, and the second arc runner element 52 likewise has a generally planar second arc runner surface 60. The first and second arc runner surfaces 60 and 62 are generally coplanar with one another and with the engagement surface 16 of the stationary contact 12. The support element 56 has a generally planar support surface 64 that is oriented parallel with and offset from the first and second arc runner surfaces 60 and 62, as can be understood from
As has been suggested elsewhere herein, arc runner assembly 2 is formed by cutting and bending a piece of stainless steel or other appropriate conductive material.
The first arc runner 36 can be said to include a proximate bend 66 that is proximate the base 42 and to further include a distal bend 68 that is distal from the base 42. The second arc runner 38 likewise includes proximate bend 70 and further includes a distal bend 72. Support 40 includes proximate bend 74, a distal bend 76, and an intermediate bend 78 situated between the proximate and distal bends 74 and 76. As can be understood from
As can be understood from the foregoing, therefore, the first arc runner surface 60 is situated coplanar with the engagement surface 16 of the stationary contact 12 and is situated at a first side thereof Likewise, the second arc runner surface 62 is oriented coplanar with the engagement surface 16 and is situated at a second, opposite side of the stationary contact 12. Since the arc runner assembly 2 is electrically connected with the first conductor 6, any arc that is formed between the stationary and movable contacts 12 and 14 could potentially be communicated along either the first arc runner element 48 or the second arc runner element 52 at the first and second arc runner surfaces 60 and 62, respectively, depending upon various factors.
In the depicted exemplary embodiment, as is indicated generally in
As is further depicted in
According to the well understood Right Hand Rule, the magnetic fields indicated by the field lines 80A and 80B will direct a DC arc along either a first movement direction 82 or a second movement direction 84 depending upon the polarity of the DC arc being interrupted. More particularly, DC current going into the plane of the page of
It is reiterated that the arc runner assembly 2 and circuit interrupter 4 can be employed in an AC application without departing from the present concept and will achieve similarly beneficial results. However, the first and second arc runner elements 48 and 52 that are situated at opposite sides of the stationary contact 12 very advantageously communicate DC arcs of either polarity along their surfaces toward the arc plates 22 for interruption of such arcs, which is highly advantageous.
While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications 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 invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.
