Fuses are often characterized as "fast-blow" or "slow-blow," according to the time they take to respond to an overcurrent condition. Fast-blow fuses (sometimes marked 'F') open quickly when the rated current is reached. Ultrafast fuses (marked 'FF') are used to protect semiconductor devices that can tolerate only very short-lived overcurrents. Slow-blow fuses (often marked 'T') can tolerate a transient overcurrent condition, but will open if the overcurrent condition is sustained.
Fuses are often sold in standardised packages to make them easily interchangeable. Cartridge fuses are cylindrical and are made in standard lengths such as 20mm, 1" and 1.25". Low-power fuses have a glass body so that the fuse wire can be inspected. High-power fuses have a stronger ceramic body filled with sand.
Blade fuses, with a plastic body and two prongs that fit into sockets, are used in automobiles.
Old electrical consumer units (also called fuse boxes) were fitted with fuse wire that could be replaced from a supply of spare wire that was wound on a piece of cardboard. Modern consumer units contain magnetic circuit breakers instead of fuses.
Source: from Federal Standard 1037C
Search Encyclopedia
|
Featured Article
|