Embodiments of the present invention generally relate to draw-out current limiting fuses. More particularly, but not exclusively, embodiments of the present invention relate to current-limiting fuses that are capable of being withdrawn from an electronic apparatus under dielectric fluid.
Liquid-filled distribution transformers, including, for example, ANSI market distribution transformers, often use current-limiting fuses that are positioned under a dielectric fluid, such as, for example, oil. Traditionally, such fuses can be difficult to replace in the field. Moreover, due to at least hardwired connections inside the transformer tank, replacement of at least some current-limiting fuses typically requires that the transformer be disconnected and moved to a repair shop. Additionally, such replacement can also involve draining at least some of the dielectric fluid from the transformer.
Alternatively, certain applications that require in-field replacement of current-limiting fuses can utilize canister fuses. Such canister fuses typically have a fuse body that is mounted in a dry well. While dry well canister applications can allow for a blown fuse to be draw out, and replaced, without draining dielectric fluid from the transformer, such canister applications can be limited in their application. For example, with respect to high voltage applications, the presence of the canister fuses in air can render such fuses susceptible to arcing. Additionally, both the fuse and the dry well can be sensitive to contamination.
An aspect of the present application is a draw-out fuse that can include a sheath comprising an insulative material, and a fuse element that is encased within the sheath. The fuse element can include a sacrificial element that melts in response to overcurrent and opens at least a portion of a circuit that extends across the draw-out fuse. The draw-out fuse can also include a plurality of contact blades that are in electrical communication with the fuse element, and which extend outwardly from at least the sheath.
Another aspect of the present application is an apparatus that can include a fuse comprising a fuse element that is encased within a sheath. The sheath can comprise an electrically insulative material. Further, the fuse element can include a sacrificial element that melts in response to overcurrent and opens at least a portion of a circuit that extends across the fuse. The fuse can further include a plurality of contact blades that are in electrical communication with the fuse element, and which extend outwardly from at least the sheath. The apparatus can further include a plurality of contact clips, each of the plurality of contact clips having a pathway that accommodates at least selective linear displacement of a contact blade of the plurality of contact blades along the pathway. The contact clip can be in electrical communication with the fuse element via, at least in part, engagement of the contact blade with a portion of a wall of the contact clip defines at least a portion of the pathway.
Additionally, an aspect of the present application is an apparatus that includes an electronic apparatus having an enclosure, the enclosure having an interior region configured to receive a dielectric fluid. The apparatus can also include a tank flange that can be mounted to the enclosure and positioned about an opening in the enclosure. The tank flange can have an aperture and a plurality of guide openings. The apparatus can further include a cap that is configured for selective positioning about the tank flange and the opening of the enclosure. Additionally, the apparatus can include a fuse that can be coupled to the cap, the fuse comprising a fuse element encased within a sheath, the sheath comprising an electrically insulative material. The fuse element can include a sacrificial element that melts in response to overcurrent and opens at least a portion of a circuit that extends across the fuse. Additionally, the fuse can further comprise a plurality of contact blades that are in electrical communication with the fuse element, and which extend outwardly from at least the sheath. The apparatus can further include a plurality of contact clips that can be positioned within the interior region of the enclosure, each of the plurality of contact clips having a pathway that accommodates at least selective linear displacement of a contact blade of the plurality of contact blades along the pathway. The contact clip can be in electrical communication with the fuse element via, at least in part, engagement of the contact blade with a portion of a wall of the contact clip that defines at least a portion of the pathway. Further, each of the plurality of guide openings can be in linear alignment with an opening of the pathway of at least one of the plurality of contact clips.
These and other aspects of the present application will be better understood in view of the drawings and following detailed description.
The description herein makes reference to the accompanying figures wherein like reference numerals refer to like parts throughout the several views.
The foregoing summary, as well as the following detailed description of certain embodiments of the present application, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the application, there is shown in the drawings, certain embodiments. It should be understood, however, that the present application is not limited to the arrangements and instrumentalities shown in the attached drawings. Further, like numbers in the respective figures indicate like or comparable parts.
Certain terminology is used in the foregoing description for convenience and is not intended to be limiting. Words such as “upper,” “lower,” “top,” “bottom,” “first,” and “second” designate directions in the drawings to which reference is made. This terminology includes the words specifically noted above, derivatives thereof, and words of similar import. Additionally, the words “a” and “one” are defined as including one or more of the referenced item unless specifically noted. The phrase “at least one of” followed by a list of two or more items, such as “A, B or C,” means any individual one of A, B or C, as well as any combination thereof.
For example, according to certain embodiments, the electronic apparatus 104 is a transformer, such as, for example, a power transformer, a shunt reactor, or substation distribution transformer. Additionally, according to the application, the transformer can be single-phase or poly-phase, e.g. three-phase. Further, for example, according to certain embodiments, the transformer can provide converted electrical power at an output of the transformer to a power grid or load. According to certain embodiments, the power transformer is a step-up or step-down transformer, and the corresponding voltages and currents are increased or decreased, depending upon the application, via operation of the transformer. Additionally, the transformer can have a conservator for retaining dielectric fluid 114 provided to the interior region 108 and radiators for cooling the transformer during operation. Further, according to certain embodiments, the transformer can also be provided with high-voltage bushings and low-voltage bushings.
According to certain embodiments, the enclosure 102 includes a canister 116 that is configured to accommodate seating of at least a portion of the draw-out fuse 100 inside the enclosure 102 of the electronic apparatus 104. However, according to other embodiments, the draw-out fuse 100 may be placed within the interior region 108 of the enclosure 102 without use of a canister 116. According to the illustrated embodiment, the canister 116 is a tubular body that can have a variety of different shapes and sizes. The wall 106 of the enclosure 102 can be coupled to the canister 116 such that the canister 116 extends into the interior region 108 of the enclosure 102. Further, while
According to the embodiment illustrated in
According to the illustrated embodiment, the canister 116 can further include, and/or be generally coupled to, the selectively removable cover or cap 118, such as, for example removable so as to provide access to the cavity 120 of the canister 116 and/or the interior region 108 of the enclosure 102. Further, according to certain embodiments, the cap 118 can be directly or indirectly coupled to the first end 130 of the canister 116 such that the cap 118 can selectively cover at least the opening 138 and/or cavity 120 of the canister 116. Further, in addition to, or in lieu of, being selectively directly or indirectly coupled to the canister 116, the cap 118 can be coupled to the enclosure 102 and/or a tank flange 128 that can be mounted to the enclosure 102 and/or positioned between the enclosure 102 and the cap 118. Additionally, according to certain embodiments, the cap 118 can be coupled to a handle 142, such as, for example, attached to a handle 142 that extends from an upper surface 144 of the cap 118, which can enhance the ease at which the cap 118 can displaced, including displaced generally linearly and/or rotationally.
Further, as discussed below, the canister 116 can be configured such that dielectric fluid 114 housed within the cavity 120 will generally remain within the canister 116, and thus be separated from other dielectric fluid within the interior region 108 of the enclosure 102 that is not within the canister 116. Moreover, the canister 116 can be configured such that dielectric fluid does not flow between the cavity 120 of the canister 116 and the other portions of the interior region 108 of the enclosure 102 that are outside of the canister 116. Thus, according to certain embodiments, additional dielectric fluids can be added to the cavity 120 of the canister 116. Further, the level of dielectric fluid within the cavity 120 of the canister 116 may or may not be at the same as the level of dielectric fluid that is within other portions of the interior region 108 of the enclosure 102.
As shown in at least
The draw-out fuse 100 can include a fuse element 158 that is encased within an electrically insulative sheath 160, and can include one or more contact blades 150a, 150b. According to the illustrated embodiment, the draw-out fuse 100 is a current-limiting fuse and has a sacrificial element, such as, for example, the fuse element 158, that melts in response to overcurrent and opens the corresponding circuit. As shown in at least
The sheath 160 can be constructed from an electrically insulative material, and can be configured to encase the fuse element 158 within an inner area 162 of the sheath 160. Thus, according to certain embodiments, the sheath 160 can have an upper wall 164a, and lower wall 164b, as well as a sidewall 164c that extends therebetween, the upper, lower, and sidewalls 164a-c generally defining the inner area 162 of the sheath 160. The sheath 160 can also be coupled to, or other provide passage through the sheath 160 for, the contact blades 150a, 150b, as discussed below, as well as accommodate passage of electrical connections between the contact blades 150a, 150b and the fuse element 158, among other related connections therebetween. For example, according to the embodiments, the sheath 160 can be configured to accommodate fuse leads 156 that are in electrical contact with the fuse element 158 to extend to locations along, or through, the sheath 160 at which the fuse leads 156 can be electrically coupled to the contact blades 150a, 150b.
According to the illustrated embodiment, a portion of the draw-out fuse 100, such as, for example, a portion of the draw-out fuse 100 at or around a first end 168 of the draw-out fuse 100, can be coupled to the cap 118. Such a coupling and/or attachment to the cap 118 can facilitate the draw-out fuse 100 being able to be withdrawn from the cavity 120 upon displacement of the cap 118 away from at least the canister 116 and/or away from the interior region 108 of the enclosure 102. For example, according to certain embodiments, the cap 118 can be coupled to a locking mechanism 172 that can securely engage a portion of the draw-out fuse 100 in a manner that can secure the draw-out fuse 100 to the cap 118. More specifically, for example, according to certain embodiments, a portion of the locking mechanism 172 may exert a clamping force against the draw-out fuse 100, including the fuse element 158, and/or the cap 118, in a manner that can secure the draw-out fuse 100 to the cap 118. Alternatively, the locking mechanism 172 may engage one or both of the draw-out fuse 100 and/or the cap 118 via an interference fit, press fit, adhesive, and/or mechanical fastener(s), such, such as, for example, bolt, screw, or, pin, as well as any combinations thereof, in a manner that can secure the draw-out fuse 100 to the cap 118.
As shown in at least
According to certain embodiments, and as shown in at least
The tank flange 128 can be mounted along an outer side 176 of the wall 106 of the enclosure 102, and can configured for interfacing with the canister 116 and/or the cap 118. Moreover, according to certain embodiments, the tank flange 128 can be configured for a locking engagement with the cap 118 that can at least assist in retaining a position of the draw-out fuse 100 within the interior region 108 of the enclosure 102. Further, a seal, such as, for example, an O-ring 178, can be positioned between the interface between the tank flange 128 and the outer surface 176 of the wall 106 of the enclosure 102 so as to hermetically seal the contents of the enclosure 102, such as, for example, the interior region 108 of the enclosure 102 and/or cavity 120 of the canister 116, including, but not limited to, the dielectric fluid 114 contained therein. Additionally, or alternatively, an interface between the cap 118 and the tank flange 128, including, for example, an interface between a portion of the bottom side 124 of the cap 118 and an upper surface 180 of the tank flange 128 can utilize a seal, such as, for example, an O-ring 178, to also assist in hermetically sealing the contents of the enclosure 102.
Referencing
The tank flange 128 can also include an aperture 186 that is sized to accommodate displacement of at least a portion of the draw-out fuse 100 into, and out of, the interior region 108 of the enclosure 102, and/or the cavity 120 of the canister 116. The aperture 186 can include one or more guide openings 188 that extend outwardly from adjacent portions of the aperture 186, and which are sized and positioned to align a corresponding contact blade 150a, 150b of the draw-out fuse 100 in position to be received by a corresponding contact clip 146. For example, according to the illustrated embodiment, the aperture 186 includes a pair of guide openings 188 in the form of outwardly extending slots, each slot having a depth and width (as indicated by “D” and “W” in
While
The contact blades 150a-b, 150a-b of the draw-out fuse 100, 100′ as well as the associated contact clips 146, 148, can be configured for secure engagement in a variety of different manners. For example, as shown in at least
When the draw-out fuse 100 is to be replaced, the user may determine if there is an absence of positive pressure on the unit, including, for example, in the canister 116 or interior region 108 of the enclosure 102 before attempting to withdraw the draw-out fuse 100. The user can then grasp the handle 142 and linearly displaced the handle 142 and/or cap 118 so as to withdraw the draw-out fuse 100 from the interior region 108 of the enclosure 102 and/or the cavity 120 of the canister 116. The draw-out fuse 100 can then be detached from the locking mechanism 172 so as to be detached from the cap 118, or vice versa, and a new or replacement draw-out fuse 100 can then be secured to the cap 118 via the locking mechanism 172. Alternatively, the new or replacement draw-out fuse 100 can be accompanied by a new or replacement locking mechanism 172 and/or cap 118. The contact blades 150a, 150b of the new or replacement draw-out fuse 100 can then be aligned with the guide openings 188 of the tank flange 128 such that the draw-out fuse 100 can linearly displaced through the tank flange 128 in an orientation that is aligned with the opening 190 of the pathway 192, and continue to be linearly displaced into subsequent receipt in the pathway of the associated contact clip 146 until the contact blades 150a, 150b are seated within the corresponding contact clip 146, as previously discussed. Further, as previously discussed, with the contact blade(s) 152a, 152 be seated in the contact clip 146, the new or replacement draw-out fuse 100 can be retained in position via at least the engagement of the contact blades 152a, 152b with the contact clips 146.
Referencing
Additionally, as shown in
According to the embodiments depicted in
Upon one or both of the contact blades 152a, 152b reaching the bottom wall 208 of the first leg 198, or otherwise bottoming out within the pathway 192′ of a contact clip 148, the draw-out fuse 100′ can be rotated in a first rotational direction about the central axis 166 of the draw-out fuse 100′. Such rotation of the draw-out fuse 100′ can be facilitated by use of the handle 142, which, as previously discussed, can be indirectly coupled to the draw-out fuse 100′ via, for example, the cap 118 and associated locking mechanism 172. Such rotation can facilitate the rotational displacement of the contact blades 152a, 152b along the second leg 200 of the pathway 192′ until the contact blades 152a, 152b reach an end wall 210 of the second leg 200. According to the illustrated embodiment, upon reaching the end wall 210 of the second leg 200, the user can release the handle 142, and the biasing element 204 can then push the draw-out fuse 100′ in the second direction such that the contact blades 152a, 152b are displaced into upwardly directed recess 202 of the second leg 200, thereby securing the contact blades 152a, 152b with the contact clip 148. Such continued biasing force of the biasing element 204 and/or the configuration of the recess 202 of the second leg 200 can at least assist in retaining the contact blades 152a, 152b in engagement with the contact clip 148. Further, the contact blades 152a, 152b can be positioned within the recess 202 such that the contact blades 152a, 152b abut against one or more adjacent walls 206a, 206b, 210 of the contact clip 148 that define at least a portion of the pathway 192′, thereby placing the contact blades 152a, 152b in electrical contact with the contact clip 148. Moreover, as previously mentioned, such engagement of the contact blades 152a, 152b with the contact clip 148 can at least assist in retaining the draw-out fuse 100′ inside the canister 116 and/or at a selected location or position within the interior region 108 of the enclosure 102.
When the draw-out fuse 100′ that is secured to contact clip 148 via a bayonet connection is to be replaced, the user may at least initially determine whether there is an absence of positive pressure on the unit, including, for example, in the canister 116 or interior region 108 of the enclosure 102, before attempting to withdraw the draw-out fuse 100. The user can then grasp the handle 142 and linearly displaced the handle 142 and/or cap 118 with sufficient force to overcome the biasing force of the biasing element 204, and thereby displace at least the fuse element in the first direction such that the contact blades 152a, 152b are removed from the recess 202 of the second leg 200 of the pathway 192′. The user may then, via use of the handle 142, rotate the draw-out fuse 100′ in a second rotational direction about the central axis 166 of the draw-out fuse 100′, the second rotational direction being opposite of the first rotational direction. Such rotation can rotatably displace the contact blades 152a, 152b along the second leg 200 until the contact blades 152a, 152b reach the first leg 198 of the pathway 192′. The user may then, again via use of the handle 142, linearly displace the draw-out fuse 100′ in the second direction, and/or utilize the biasing force of the biasing element 204, such that the contact blades 152a, 152b pass through at least the first leg 198 of the pathway 192′ of the corresponding contact clip 148, as well as through the guide opening 188 of the tank flange 128, thereby withdrawing the draw-out fuse 100′ from the electronic apparatus 104. The draw-out fuse 100′ can then be replaced, and a new or replacement draw-out fuse 100′ can then be connected to the contact clips 148 in a manner similar to that previously discussed above with respect to the draw-out fuse 100 shown in at least
Referencing
The draw-out fuse 100, 100′ discussed above can be replaced while the electronic apparatus 104 is already down due to a blown fuse element 158. Alternatively, the electronic apparatus 104 can be taken offline, and the draw-out fuse 100, 100′ can be relatively quickly replaced. The status as to whether the draw-out fuse 100, 100′ has operated, or is blown, can be monitored in a variety of different manners, including, for example, by a resistance meter across the e draw-out fuse 100, 100′ or other related components.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.
The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/612,399, which was filed on Dec. 30, 2017, and is incorporated herein by reference in its entirety.
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Number | Date | Country | |
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20190371559 A1 | Dec 2019 | US |
Number | Date | Country | |
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62612399 | Dec 2017 | US |