A fuse is a device which is used for the protection of electrical wires, cables and other electrical equipments against overloading and short circuit. Fuse consists of a fuse element which is a thin wire mounted on an insulated base. When disproportionate current flows through this wire, it gets heated and destroyed. This breaks the circuit. Generally fuse is connected in series with the device. Materials used for making fuse wires are tin, lead, silver, zinc, aluminium and copper. An alloy of lead and tin in the ratio 37% and 63% respectively is used for the small current applications. Since silver is not subjected to oxidation, it is preferred for above 15A applications. There are two types of fuses. They are rewirable fuse and totally enclosed or cartridge fuse. In a rewirable fuse, blown out wire element can be replaced by a new wire. This is the cheapest one and has two units namely base unit and fuse carrier. Both these units are fixed on the porcelain chassis. This type of fuse element is either open or semi-enclosed. Totally enclosed or cartridge fuse is enclosed in a totally enclosed insulated container. There are two types in this category. They bare D-type cartridge fuse and link-type cartridge fuse. D-type cartridge fuse is enclosed in a tubular insulating container. Link type cartridge fuse which is also known as high-rupturing capacity (HRC) cartridge fuse consists of a ceramic body made of steatite, fuse element of silver, clean silica quartz, asbestos washers, porcelain plugs, brass end caps and copper tags.
No comments:
Post a Comment