S&c Electric Company

Hiram S Jackson

Henry W Scherer

Bruce A Biller

Roy T Swanson

David W Zabel

Leonard V Chabala

Roy R Swanson

A current-limiting device is provided having a low profile configuration (generally flat polyhedron) that defines a cavity of predetermined dimensions and an elongated circuitous path through the cavity. The device also includes provisions for supporting a current-limiting fusible element along the path. The cavity is filled with a pulverulent arc-quenching filler material. In one specific arrangement, the path of the fusible element is defined by one or more U-shaped sections substantially spanning the length or width of the cavity. The fusible element is arranged in a predetermined geometry to include a length of the fusible element that is longer than the overall straight-line path via a configuration of steps or bends along its length.

Method of assembling a fuse housing

A low-exhaust composite drop-out assembly is provided that is utilizable in a standard cutout mounting in electrical power distribution systems. The composite drop-out assembly includes current-limiting and low-current clearing sections and is easily removable from mounting for servicing. The sections are efficiently arranged in a side by side configuration.. The low-current clearing section includes a fuse-robe assembly having a replaceable fuse cartridge. Accordingly, the low-current clearing section is simply and economically renewable for reuse whether or not the current-limiting section has operated. Further, the current-limiting section need not be replaced if only the low-current clearing section operated in response to overcurrent in a low range. Additionally, the sections are separable so that the low-current clearing section can be reused after simple refusing even when the current-limiting section has operated.

Current-limiting fuse and housing arrangement having a seal between an

Current-limiting fuse and housing arrangement

Electrical current limiter for power distribution systems

A low-exhaust composite drop-out assembly is provided that is utilizable in a standard cutout mounting in electrical power distribution systems. The composite drop-out assembly includes current-limiting and low-current clearing sections and is easily removable from the mounting for servicing. The sections are efficiently arranged in a side by side configuration. The low-current clearing section includes a fuse-tube assembly having a replaceable fuse cartridge. Accordingly, the low-current clearing section is simply and economically renewable for reuse whether or not the current-limiting section has operated. Further, the current-limiting section need not be replaced if only the low-current clearing section operated in response to overcurrent in a low range. Additionally, the sections are separable so that the low-current clearing section can be reused after simple refusing even when the current-limiting section has operated.

Fuse assembly with low exhaust and replaceable cartridge

Electrical fuse limiter for power distribution systems

An improved current-limiting section is provided for an interrupting device. A main-current-path section of the interrupting device carries substantially all of the normal, load current while only a negligible portion of the current flows through a higher-impedance current-limiting section. Upon operation of the interrupting device, the contacts of a switch in the main-current section are rapidly separated to create one or more gaps. Upon the creation of the one or more gaps, the current is transferred into the current-limiting section. The current-limiting section includes a plurality of fusible elements. The fusible elements are thin, elongated, conductive ribbons. One or more of the fusible elements has a first predetermined pattern of reduced cross-sectional areas that is different than a second predetermined pattern of reduced cross-sectional areas provided in the one or more remaining fusible elements such that for low overcurrent conditions, the one or more fusible elements having the second predetermined pattern melt and have gaps created therein at an earlier time than the one or more fusible elements having the first predetermined patterns. At high overcurrent conditions, the melting characteristics of the fusible elements having the first predetermined pattern and the melting characteristics of the fusible elements having the second predetermined pattern are substantially equal.

Interrupting device with improved current-limiting arrangement

An improved switch for a high-voltage device in which ignition of a power cartridge moves an insulative piston located in a conductive member, into a passageway in an insulative liner, said piston moving a contact through the passageway and away from the conductive member to break an electrical interconnection between the conductive member and the movable contact, the switch including an insulative housing,

Pressure-operated switch for a high-voltage interrupting module

An improved switch for a high-voltage device in which ignition of a power cartridge moves an insulative piston located in a conductive member, into a passageway formed in an insulative liner, said piston moving a contact through the passageway and away from the conductive member to break an electrical interconnection between the conductive member and the movable contact and to form a gap therebetween, thereby opening the switch; the bore and the passageway being aligned,

An improved fuse tube for a high voltage fuse contact used to interrupt low and high fault currents. The fuse tube has an arc-extinguishing bore into which a fuse link is insertable. The fuse link includes an arc-extinguishing sheath surrounding a pair of separable terminals and a fusible element normally between the terminals. An arc established and elongated between the separating terminals after the fusible element melts and decomposes the bore, the sheath, or both to rapidly evolve large amounts of arc-extinguishing gases which are exhausted from an open end of the bore. A conductive chamber in the bore is electrically connected with one of the terminals and surrounds a portion of the sheath and the terminals. A mild taper is formed in the bore so that its larger end is at the open bore end. The chamber permits the fuse link to be positioned deep within the bore so that low fuse current interruption is not compromised. During high fault current interruption, the arc transfers from one of the terminals to the chamber, thus limiting the extent at which the arc can be elongated. This function of the chamber in combination with the mild taper results in efficient high fault current interruption.

High-voltage fuse cutout

A lead weight or other mass is crimped to the contact button assembly of the arcing rod of a high-voltage alternating-current power fuse thereby increasing the mass of the arcing rod without increasing the diameter of the rod. The increased mass of the arcing rod decreases the velocity with which the arcing rod moves upon fusing of the fusible member thereby decreasing the rate of elongation of the arc drawn between the end of the arcing rod and the stationary ferrule at the other end of the fuse. Under high current conditions, the shorter arc length drawn in the fuse reduces the pressure of the arc-extinguishing gas generated by the arc, thereby reducing the risk that an economically constructed fuse will burst in those situations when the arc is not interrupted at the first current zero. This result is accomplished without adversely affecting operation of the fuse and interruption of the arc at low current levels.

Growing community of inventors

Morton Grove, IL, United States of America

Hiram S Jackson