Patent Application
20140202990
The present invention relates to arc runners used with circuit breakers.
Circuit breakers are one of a variety of overcurrent protection devices used for circuit protection and isolation. The circuit breaker provides electrical protection whenever an electric abnormality occurs. In a circuit breaker, current enters the system from a power line and passes through a line conductor to a stationary contact fixed on the line conductor, then to a movable contact. The movable contact can be fixedly attached to an arm and the arm can be mounted to a rotor. As long as the stationary and movable contacts are in physical contact, current passes from the stationary contact to the movable contact and out of the circuit breaker to down line electrical devices.
In the event of an overcurrent condition (e.g., a short circuit), extremely high electromagnetic forces can be generated. The electromagnetic forces repel the movable contact away from the stationary contact. Because the movable contact is fixedly attached to a rotating arm, the arm pivots and physically separates the stationary and movable contacts thus tripping the circuit. Upon separation of the contacts and blowing open the circuit, an arcing condition occurs. The breaker's trip unit will trip the breaker which will cause the contacts to separate. Also, arcing occurs during normal “ON/OFF” operations on the breaker. It is desirable to suppress resultant arcs.
A typical method of suppressing the arc is to direct it into an arc chute, which is generally a series of metal plates that dissipate the energy of the arc. This arc chute is situated proximate to the stationary contact point of the circuit. An arc runner is used to direct the arc to the arc chute. The arc runner covers the exposed area of the line conductor. Since the arc runner provides a pathway for the arc to follow to the arc chute, it is subject to intensely high temperatures.
During higher fault interruptions, particularly those associated with DC currents, the arc can be resistant to movement into the arc chute because the magnetic field created by the permanent magnets in the arc chute may not be sufficiently strong against the gas dynamic force to push and stretch the arc into lower arc plates. The lack of engagement between the arc and the lower arc plates may cause longer arcing time and damage to the arc chute and breaker.
Embodiments of the present invention are directed to arc runners that can reduce arcing time and/or inhibit damage to the arc chute and/or breaker.
Some embodiments are directed to bi-directional direct current (DC) circuit breakers.
Some embodiments are directed to circuit breakers that include: (a) an arc chamber; (b) an arc chute comprising a plurality of arc plates in the arc chamber; (c) a line conductor in the arc chamber, the line conductor having a lower body portion and an upwardly extending arm with a free end, the arm residing above the lower body portion; (d) a stationary contact held by the arm of the line conductor, the stationary contact residing adjacent to the arc plates; and (e) a non-ferromagnetic arc runner held by the line conductor in the arc chamber. The arc runner is at least one of (i) attached to the lower body portion of the line conductor and resides forward of the stationary contact with a portion residing under a bottom arc plate or (ii) attached to the arm of the line conductor and resides at least partially on a substantially common plane as the stationary contact with at least one downwardly extending sidewall that extends down toward the lower body portion of the line conductor a distance forward of the stationary contact with a portion residing under a bottom arc plate, whereby the arc runner defines an arc path that leads to the underside of one or more of the lower arc plates.
The arc runner can have forward facing spaced apart segments defining a gap space therebetween.
The arc runner can have a pair of spaced apart fingers that are planar and substantially horizontally oriented.
The arc runner can have a pair of spaced apart substantially vertically extending sidewalls.
The circuit breaker can include a non-conductive line conductor cover residing over an upper surface of the lower portion of the line conductor.
The arc runner can be attached to the lower body portion and can have curved shape with upper and lower substantially parallel segments. The upper segment can have a free end that faces the arc plates and resides a distance under the arm of the line conductor. The lower segment can reside adjacent the lower body portion of the line conductor and spaced apart below the line conductor arm.
The arc runner can be attached to the lower body portion and can have a body with legs that rise up to a location above or proximate the arm of the line conductor proximate the stationary conductor, then travel down to a forward planar segment that resides under the bottom arc plate.
The circuit breaker can include a line conductor cover with a lower wall that merges into an upper arm that tapers upward to a free end that terminates before the stationary conductor. The line conductor cover can include a laterally extending slot sized and configured to slidably receive the arm of the line conductor so that the line conductor arm resides under the line conductor cover arm and the lower portion of the line conductor cover resides above the line conductor lower body portion.
The arc runner can be an auxiliary arc runner and the circuit breaker can also include a stationary arc runner that resides in front of the stationary conductor on the arm of the line conductor.
The arc runner can be attached to the line conductor arm and can have two spaced apart downwardly extending walls, one residing on each side of the arm and extending a distance forward of the stationary contact.
The circuit breaker can include a reverse loop cover residing on the arm of the line conductor spaced apart from the stationary contact and away from the free end of the line conductor.
The arc runner can be an auxiliary arc runner that is attached to the line conductor arm and the circuit breaker can include a stationary arc runner that resides in front of the stationary conductor on the arm of the line conductor and a line conductor cover residing on the lower body portion of the line conductor. The auxiliary arc runner can have two spaced apart downwardly extending walls with lower ends residing above the line conductor lower body with a gap space therebetween, one wall residing on each side of the line conductor arm with outwardly extending narrow fingers on the forward ends thereof.
The circuit breaker can include a line conductor cover residing on the lower body portion of the line conductor. The arc runner can have two spaced apart downwardly extending walls with lower edges residing proximate the line conductor cover, one residing on each side of the line conductor arm with outwardly extending downwardly and outwardly extending substantially planar fingers on the forward ends.
The arc runner can have a forward end portion with fingers having a gap space therebetween that reside a one on each side of the stationary contact.
The gap space has a width that is greater than a width of the stationary contact and/or adjacent arc plate.
The circuit breaker can include a line conductor cover residing on the lower body portion of the line conductor. The arc runner, line conductor and line conductor cover each can include at least one aligned aperture that receives an attachment member that attaches the arc runner to the line conductor.
Yet other embodiments are directed to an arc chamber assembly. The assembly includes: an arc chamber having a molded body; an arc chute including a plurality of arc plates in the arc chamber; a movable arm holding a movable contact in the arc chamber; and a line conductor assembly with a line conductor having a lower body portion and an upwardly extending arm with a free end, the arm residing above the lower body portion. The line conductor assembly includes a stationary contact that cooperates with the movable contact and a non-ferromagnetic arc runner attached to the line conductor residing in the arc chamber. The arc runner is at least one of (a) attached to the lower body portion of the line conductor and resides forward of the stationary contact with a portion residing under a bottom arc plate or (b) attached to the arm of the line conductor and resides on a substantially common plane as the stationary contact with at least one downwardly extending sidewall that extends down toward the lower body portion of the line conductor a distance forward of the stationary contact with a portion residing under a bottom arc plate. The arc runner defines an arc path that leads to the underside of one or more of the lower arc plates. The arc chamber assembly also includes a non-conductive line conductor cover residing over the line conductor lower body portion.
Still other embodiments are directed to arc runner assemblies. The assemblies include: an elongate line conductor having a lower body portion and an upwardly extending arm, the line conductor holding a stationary electrical contact on a forward end portion of the arm for a direct current (DC) circuit breaker; a non-ferromagnetic arc runner attached to the elongate line conductor, wherein the arc runner has forward extending segments that define a gap space therebetween, the segments sized and configured to reside on opposing lateral sides of the line conductor arm and/or stationary contact; and a non-conductive line conductor cover residing over the line conductor lower body portion.
The spaced apart segments can be fingers that extend down from the line conductor arm or that extend up from the lower body portion of the line conductor and face the arc plates.
The spaced apart segments can be upper portions of legs that rise up from the lower body portion of the line conductor then travel down toward a front planar end of the arc runner.
The arc runner can be a first arc runner and the assembly can include a second arc runner that is held by the arm of the line conductor.
Still other embodiments are directed to methods of directing arcs in an arc chute of a circuit breaker. The methods include: (a) providing a circuit breaker with an arc chamber comprising an arc chute with arc plates and a line conductor with a stationary conductor and least one arc runner; and (b) directing an electrical arc to travel along an arc path that extends to an underside of a bottom arc plate of the arc chute using the arc runner.
Further features, advantages and details of the present invention will be appreciated by those of ordinary skill in the art from a reading of the figures and the detailed description of the preferred embodiments that follow, such description being merely illustrative of the present invention.
It is noted that aspects of the invention described with respect to one embodiment, may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination. Applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner. These and other objects and/or aspects of the present invention are explained in detail in the specification set forth below.
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. Like numbers refer to like elements and different embodiments of like elements can be designated using a different number of superscript indicator apostrophes (e.g., 40, 40′, 40″, 40″′).
In the drawings, the relative sizes of regions or features may be exaggerated for clarity. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90° or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. The term “about” refers to numbers in a range of +/−20% of the noted value.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes,” “comprises,” “including” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
The term “auxiliary arc runner” refers to an arc runner that is used with another arc runner and is configured to encourage an electrical arc to travel from a position above the bottom arc plate to a location underneath a lower positioned arc plate, typically underneath a bottom arc plate to make the lower or bottom arc plate more involved in arc interruption relative to conventional arc runner configurations.
The term “non-ferromagnetic” means that the noted component is substantially free of ferromagnetic materials so as to be suitable for use in the arc chamber (non-disruptive to the magnetic circuit) as will be known to those of skill in the art.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Turning now to the figures,
Referring to
The term “lower arc plate” refers to an arc plate 25 residing below the movable (rotating) arm 35 that holds a movable contact 35c, when deployed to reside proximate the stationary contact 30, and/or that resides below or in a common plane as the stationary contact 30.
As will be discussed further below, the figures illustrate four exemplary configurations of a line conductor assembly 45 although other configurations may also be used. The respective assemblies 45 include at least one arc runner 40, 40′, 40″, 40″′ respectively. The arc runner 40, 40′, 40″, 40″′ can define a current pathway to allow an arc to engage one or more of the lower arc plates 251 thereby reducing arcing time. At least a portion of a respective arc runner 40, 40′, 40″, 40″′ can reside proximate one or more of the lowest three (3), lowest two (2) and/or a bottom arc plate 25b of the circuit breaker in the orientation shown in
The at least one arc runner 40, 40′, 40″, 40″′ can be positioned to have a portion that resides proximate and under the bottom arc plate 25b as shown, for example, in
In the embodiment shown with respect to
The arc runner 40, 40′, 40″, 40″′ can be held by, typically attached to, the line conductor 32. The arc runner 40, 40′, 40″, 40″′ can be located to have at least a portion that resides in front of the stationary contact 30 and can have portions that can be located at (substantially) the same plane or below the stationary contact 30. The arc runner 40, 40′, 40″, 40″′ can have a forward end 40e that resides closely spaced apart and below a bottom arc plate 25b.
The electrical path 40p of the arc runner 40, 40′, 40″, 40″′ can lead to an underside 25u of the bottom arc plate 25b as shown, for example, in
The arc runner 40, 40′, 40″, 40″′ can be formed as a monolithic single or unitary body of a non-ferromagnetic material such as stainless steel, copper, and the like. In other embodiments, the runner 40, 40′, 40″, 40″′ can be a multiple component device of one or different non-ferromagnetic materials.
In some particular embodiments, the circuit breaker 10 can be a bi-directional direct current (DC) molded case circuit breaker (MCCB). See, e.g., U.S. Pat. Nos. 5,131,504 and 8,222,983, the contents of which are hereby incorporated by reference as if recited in full herein. The DC MCCBs can be suitable for many uses such as data center, photovoltaic, and electric vehicles applications. The circuit breakers 10 can be rated for voltages between about 1 V to about 5000 volts (V) DC and/or may have current ratings from about 15 to about 2,500 Amperes (A). However, it is contemplated that the circuit breakers 10 and components thereof can be used for any voltage, current ranges and are not limited to any particular application as the circuit breakers can be used for a broad range of different uses.
In some embodiments, the circuit breakers 10 can be suitable as AC circuit breakers or both AC and DC circuit breakers.
As is known to those of skill in the art, Eaton Corp. has introduced a line of molded case circuit breakers (MCCBs) designed for commercial and utility scale photovoltaic (PV) systems. Used in solar combiner and inverter applications, Eaton PVGard™ circuit breakers are rated up to 600 amp at 1000 Vdc and can meet or exceed industry standards such as UL 489B, which requires rigorous testing to verify circuit protection that meets the specific requirements of PV systems. However, it is contemplated that the circuit breakers 10 can be used for various applications with corresponding voltage capacity/rating.
The arc runner 40, 40′, 40″, 40″′ can be configured to allow a respective arc to move away from the forward surface 40s and onto one, both and/or either lateral side of the stationary contact 30 depending on the DC current direction, typically on one side of the contact 30 (right or left). The arc runner 40, 40′, 40″, 40″′ can have a forward surface 40e that resides proximate to and below the bottom arc plate 25b so to guide the arc into the arc chute 12.
As noted above, in the third and fourth embodiments shown in
The arc runner 40, 40′, 40″, 40″′ can have an upper portion with spaced apart fingers 140 that face (and reside) adjacent the stack 25. As shown in
As shown in
In some embodiments, as shown in
As also shown, the line conductor support 170 and arc runner 40″′ can include a respective leg 240l, 170l, that rises above the line conductor 32 and each can include a free forward end 40e, 170e. The free end of the line conductor support 170e can abut and reside beneath the free end of the arc runner 40e.
Referring to
As noted above, the arc runner 40, 40′, 40″, 40″ is typically made of non-ferromagnetic conductive (e.g., metal) material. The arc runner 40, 40′, 40″, 40″′ can be attached to the line conductor 32 via any suitable attachment means, including, one or combinations of, screws, pins, welding, brazing, adhesives, snap-fit features, bayonet features, frictional engagement and/or matable features and the like.
As shown in
In some embodiments, a respective arc runner may optionally be attached to both the line conductor lower body portion 32b and the arm 130.
The reverse loop cover 80 (where used) and line conductor cover 70 are non-conductive. The covers can comprise “fish paper”, CFM and/or glass filled polyester or other suitable non-conductive and/or electrical insulation material. In some embodiments, the attachment member 50 and the line conductor 32 are non-ferromagnetic conductive members. The line conductor 32 can comprise copper, a suitable grade stainless steel or any suitable non-ferromagnetic material. The contact 30 is conductive, typically a silver alloy. The mating parts for the above, e.g., the moving contact 35c and moving arm 35 can comprise the same materials, e.g., silver alloy (for the contact 35c) and copper, respectively. It is also contemplated that the line conductor cover 70, and reverse loop cover (where used), can be formed using a non-conductive insulator material which can be applied as a sheet of material, an adhesive, film, ceramic or polymer material.
The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the invention.
