Draw-out current limiting fuse

Patent metadata

Field	Value
Publication number	US-11133145-B2
Application number	US-201816237218-A
Country	US
Kind code	B2
Filing date	Dec 31, 2018
Priority date	Dec 30, 2017
Publication date	Sep 28, 2021
Grant date	Sep 28, 2021

Abstract

A current-limiting fuse for an electronic apparatus, such as, for example, a transformer. The fuse can be withdrawable under a liquid insulating medium, such as oil, and is capable of being replaceable in the field. The fuse can include a fuse element that is encased within an electrically insulative sheath. Additionally, a plurality of contact blades can extend from a lower portion of the fuse and be securely engaged with contact clips that are in electrical communication with one or more components of the electronic apparatus. The contact blades can be positioned within a dielectric insulating medium while a reminder of the fuse between the contact blades and the enclosure can be positioned within an air gap. Further, the contact blades can accommodate seating of the fuse within the enclosure and/or an associated canister.

First claim

The invention claimed is:

1. A draw-out fuse comprising:
a sheath comprising an insulative material;
a fuse element encased within the sheath, the fuse element including a sacrificial element that is configured to melt in response to overcurrent and open at least a portion of a circuit that extends across the draw-out fuse; and
a plurality of contact blades in electrical communication with the fuse element and extending outwardly from at least the sheath,
wherein the plurality of contact blades comprise a first contact blade electrically coupled to a first contact of the fuse element and a second contact blade directly electrically coupled to a second contact of the fuse element, the first and second contact blades extending outwardly from diametrically opposite sides of the sheath, and
wherein the first and second contact blades extend along a common plane that is parallel to a radius of the sheath and that is perpendicular to a central axis of the draw-out fuse.

2. The draw-out fuse of claim 1 , wherein the first contact blade is directly electrically coupled to the first contact of the fuse element by a first fuse lead, and the second contact blade is directly electrically coupled to the second contact of the fuse element by a second fuse lead.

3. The draw-out fuse of claim 1 , wherein the draw-out fuse extends between a first end and a second end of the draw-out fuse along the central axis of the draw out fuse, and wherein the plurality of contact blades extend radially outwardly around the second end of the draw-out fuse.

4. The draw-out fuse of claim 3 , further including a cap and a locking mechanism, the locking mechanism configured to securely couple the first end of the draw-out fuse to the cap.

5. The draw-out fuse of claim 4 , wherein the cap is coupled to a handle.

6. The draw out fuse of claim 1 , wherein the plurality of contact blades have a pin configuration.

7. An apparatus comprising:
a fuse comprising a fuse element encased within a sheath, the sheath comprising:
an electrically insulative material, the fuse element including a sacrificial element that is configured to melt in response to overcurrent and open at least a portion of a circuit that extends across the fuse, and wherein the fuse further comprises a plurality of contact blades in electrical communication with the fuse element and extending outwardly from at least the sheath; and
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 being 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.

8. The apparatus of claim 7 , further including a tank flange having an aperture and a plurality of guide openings, the tank flange configured to mount to an enclosure, each of the plurality of guide openings being size to accommodate passage of at least one of the plurality of the contact blades through the tank flange as other portions of the fuse are linearly displaced through the aperture.

9. The apparatus of claim 8 , wherein each of the plurality of guide openings are positioned about the tank flange to align with an opening of the pathway of at least one of the plurality of contact clips.

10. The apparatus of claim 7 , wherein the pathway of each contact clip of the plurality of contact clips extends linearly from an open end of the pathway to a bottom wall of the pathway, and wherein each contact blade of the plurality of contact blades is configured to be seated upon the bottom wall such that the contact blade is in electrical communication with the contact clip.

11. The apparatus of claim 10 , wherein the plurality of contact blades are configured to retain a position of the fuse relative to at least one of the contact clips when the contact blade is seated upon the bottom wall.

12. The apparatus of claim 7 , wherein the pathway of each contact clip of the plurality of contact clips is configured for a bayonet connection with a contact blade of the plurality of contact blades.

13. The apparatus of claim 12 , wherein the pathway includes a first leg and a second leg, the second leg extending in a direction that is different than, and away from, the first leg.

14. The apparatus of claim 7 , wherein the plurality of contact clips are secured to a canister, and wherein the fuse is positioned within a cavity of the canister.

15. The apparatus of claim 14 , wherein the fuse extends between a first end and a second end, the plurality of contact blades being positioned around the second end of the fuse, and further including a dielectric fluid contained within the canister, the dielectric fluid having a fluid level within the cavity that covers the plurality of contact blades positioned within the cavity but which provides an air gap between at least a portion of a distance between the plurality of contact blades and the first end of the fuse.

16. The apparatus of claim 7 , further comprising:
an electronic apparatus having an enclosure, the enclosure having an interior region configured to receive a dielectric fluid;
a tank flange mounted to the enclosure and positioned about an opening in the enclosure, the tank flange having an aperture and a plurality of guide openings; and
a cap configured for selective positioning about the tank flange and the opening of the enclosure;
wherein the fuse is coupled to the cap,
wherein the plurality of contact clips are positioned within the interior region of the enclosure, and
wherein each of the plurality of guide openings is in linear alignment with an opening of the pathway of at least one of the plurality of contact clips.

17. The apparatus of claim 16 , further including a canister, at least a portion of the canister positioned within the interior region, at least a portion of the fuse being positioned within a cavity of the canister, and further including a dielectric fluid contained within the canister, the dielectric fluid having a fluid level within the cavity that covers the plurality of contact blades positioned within the cavity but also provides an air gap around another portion of the fuse.

18. The apparatus of claim 16 , wherein the electrical apparatus is a transformer, and wherein the pathway of each contact clip of the plurality of contact clips is configured for a bayonet connection with a contact blade of the plurality of contact blades.

19. The apparatus of claim 16 , wherein the electrical apparatus is a transformer, and wherein the pathway of each contact clip of the plurality of contact clips is configured for a bayonet connection with a contact blade of the plurality of contact blades.

20. The apparatus of claim 7 , wherein the pathway of each contact clip of the plurality of contact clips is configured for a bayonet connection with a contact blade of the plurality of contact blades.

21. The apparatus of claim 20 , wherein the pathway includes a first leg and a second leg, the second leg extending in a direction that is different than, and away from, the first leg.

22. An electronic apparatus comprising:
an enclosure, the enclosure having an interior region configured to receive a dielectric fluid; and
a plurality of contact clips positioned within the interior region of the enclosure, each of the plurality of contact clips ha

Assignees

• Abb Power Grids Switzerland Ag

Inventors

• Menon Suresh

Classifications

• H01H85/042 Primary

  General constructions or structure of high voltage fuses, i.e. above 1000 V · CPC title

• H01H85/485

  the fuse being provided with bayonet-type locking means · CPC title

• H01H85/48

  Protective devices wherein the fuse is carried or held directly by the base · CPC title

• H01H2085/0291

  Structural association with a current transformer · CPC title

• H01H85/143

  Electrical contacts; Fastening fusible members to such contacts · CPC title