A fuses are an electrical safety device that operates to provide over current protection of an electrical circuit.Its essential component is a metal wire or strip that melts when too much current flows through it, thereby stopping or interrupting the current.
Electrical Fuse have been use as essential safety devices from the early days. Moreover, Today there are thousands of different fuse designs which have specific current and voltage ratings, breaking capacity and response times, depending on the application.
A fuse is an automatic means of removing power from a faulty system.
A fuse was design by Thomas Edison in 1900 as part of his electric distribution system.
A fuse consists of a metal strip or wire fuse element, of small cross-section compare to the circuit conductors. The resistance of the element generates heat due to the current flow.
The size and construction of the element is determine so that the heat produce for a normal current does not cause the element to attain a high temperature. These fuses element is made up of zinc, copper, silver, aluminum, or alloy to provide stable characteristics.
Therefore, The element must not be damaged by minor harmless surges of current. The fuse must not oxidize or change its behavior after possibly years of service.
The speed at which a fuse blows depends on how much current flows through it and the material of which the fuse is made.Fuses have different characteristics of operating time compared to current. fast-blow fuse may require twice its rated current to blow in 0.1 seconds.Fuse selection depends on the load’s characteristics.
Moreover, The fast blowing fuses are design for the most sensitive electrical equipment. Where a short exposure could be very damage to an overload circuit.
- Rated Voltage
The voltage rating of the fuse must be equal to or, greater than, what would become the open-circuit voltage.Rated voltage should be higher than the maximum voltage source it would have to disconnect.Connecting fuses in series does not increase the rated voltage of the combination, nor of any one fuse.
- Breaking Capacity
The breaking capacity is the maximum current that can safely be interrupted by the fuse.
- Rated Current
A maximum current that the fuse can continuously conduct without interrupting the circuit.