Fuses

Fuses:

Fuses Definition : Fuses Definition States that : A fuses is a short piece of metal, inserted in the circuit, which melts when excessive current flows through it and thus breaks the circuit. The fuse element is generally made of materials having low melting point, high conductivity and least deterioration due to oxidation e.g., silver copper etc. It is inserted in series with theĀ circuit to be protected. Under normal operating conditions, the fuse element is at a temperature below its melting point. Therefore, it carries the normal current without overheating. However, when a short-circuit or overload occurs, the current through the fuse increases beyond its rated value. This raises the temperature and fuse element melts (or blows out), disconnecting the circuit protected by it. In this way, a fuse protects the machines and equipment from damage due to excessive currents. The time required to blow out the fuse depends upon the magnitude of excessive …


Types of Fuses : Fuse is the simplest current interrupting device for protection against excessive currents. Since the invention of first fuse by Edison, several improvements have been made and now-a-days, a variety of Types of Fuses are available. Some fuses also incorporate means for extinguishing the arc that appears when the fuse element melts. In general, Types of Fuses may be classified into : Low voltages fuses High voltage fuses It is a usual practice to provide isolating switches in series with fuses where it is necessary to permit fuses to be replaced or rewired with safety. If such means of isolation are not available, the Types of Fuses must be so shielded as to protect the user against accidental contact with the live metal when the fuse carrier is being inserted or removed. Low Voltage Fuses: Low voltage fuses can be subdivided into two classes viz., Semi-enclosed rewireable fuse High rupturing capacity (H.R.C.) cartridge fuse. 1. …