Precision fusing arrangement
AssigneeAT&T Bell Laboratories
InventorAlfred O. Schwarz
Life of this patent
Estimating the term…
Abstract
A fused station protector is disclosed wherein the fuse links have precisely controlled fusing characteristics. A shrink away foam element (28) encloses a portion of the fuse link (26) to provide a potential hot spot for slight current excesses. The remainder of the fuse link is in contact with arc quenching material (27) for extinguishing potential power arcs. Thus, the protector provides a precise fusing characteristic for slight current excesses and arc quenching capability for severe current excesses.
Claims8
A circuit protector comprising an insulative base having an elongated cavity,
- a line terminal held within the base and protruding into one end portion of the cavity,
- a station terminal held within the base and protruding into the other end portion of the cavity,
- a fuse link connected between the line and station terminals within the cavity, and
- a pellet of insulating foam enclosing a portion of the fuse link, the pellet of insulating foam being a material that shrinks away from the fuse link when the fuse link generates heat upon conducting a fault current for producing a cavity around the fuse link to provide a localized potential hot spot with precise fusing properties.
A circuit protector for telecommunication circuits generally of the type for providing over voltage protection by including voltage overload protector means including an arrester device for diverting a high voltage potential from the circuit being protected to ground, the circuit protector further including
- fusing means having a serial fusing link connected in the circuit and a foam pellet enclosing a predetermined portion of the fusing link to shield against surface oxidation, the foam material being of a type that shrinks away from the fuse link when hot to provide a potential hot spot in a cavity operable at a precise slight current overload point.
A fusing device of the type including a serial fusing link responsive to a current overload condition by melting to produce an open circuit, the fusing device comprising means for precisely controlling the response of the fusing device to a current overload condition, said means including a foam element located on the serial fusing link for enclosing a predetermined portion of same, the foam element being an insulative material that shrinks away from the link for making a cavity producing an unsupported section of the serial fusing link to provide a potential hot spot responsive to a slight current overload condition to precisely define the fusing point of the device.
Dependencies are inferred from the claim text.