High voltage current limiting fuse with improved low overcurrent interruption performance

A high voltage current limiting fuse, which comprises:

• an elongated casing of electrically insulative material having an interior cavity;
• a pair of electrically conductive end terminals closing each of the opposite ends of said casing;
• an electrically conductive partition terminal connected to the inside walls of the casing, said partition terminal being disposed at a distance along the length of the casing and extending across said casing, dividing said interior cavity of said casing into two electrically series-connected sections, a short circuit section and a low overcurrent section;
• the short circuit section comprising at least one elongated fusible element of electrically conductive material disposed within said casing and electrically connected between the first end terminal and the partition terminal, and a pulverulent arc-quenching filler of electrically insulative material within said casing generally surrounding said at least one fusible element in said short circuit section;
• and,
• the low overcurrent section comprising at least one elongated fusible element of electrically conductive material disposed within said casing and electrically connected between the second end terminal and the partition terminal, at least one elongated sleeve of electrically insulative material having an interior cavity spaced around a portion of said at least one fusible element, said at least one sleeve having a pair of gas-permeable, pulverulent-tight, seals closing each of the opposite ends of said sleeve, said seals being formed by at least one of melt crimping respective opposite ends of said sleeve together with said fusible element, heat shrinking each of the opposite ends of said sleeve over said fusible element, and taping the opposite ends of said sleeve to the fusible element, and a pulverulent arc-quenching filler of electrically insulative material within said casing generally surrounding said at least one fusible element and said at least one sleeve in the low overcurrent section.

A high voltage current limiting fuse, which comprises:

• an elongated casing of electrically insulative material having an interior cavity;
• a pair of electrically conductive end terminals closing each of the opposite ends of said casing;
• an electrically conductive partition terminal connected to the inside walls of the casing, said partition terminal being disposed at a distance along the length of the casing and extending across said casing, dividing said interior cavity of said casing into two electrically series-connected sections, a short circuit section and a low overcurrent section;
• the short circuit section comprising at least one elongated fusible element of electrically conductive material disposed within said casing and electrically connected between the first end terminal and the partition terminal, and a pulverulent arc-quenching filler of electrically insulative material within said casing generally surrounding said at least one fusible element in said short circuit section;
• and,
• the low overcurrent section comprising an elongated block of insulative material having a plurality of channels extending through the length thereof and disposed within said casing between the second end terminal and the partition terminal, and at least one elongated fusible element of electrically conductive material threaded within said channels of said block and electrically connected between the second end terminal and the partition terminal.