FUSE

Fuse:

Fuse is a wire of short length or thin strip of material having low melting point and is inserted in an electric circuit as a protective device to the flow of excessive current through the circuit.The time for blowing out of fuse depends upon the magnitude of excessive current

Larger the current,the more rapidly the fuse will blow.Fuse provides cheapest type of protection,need no maintenance,affords current limiting effect under shot circuit conditions and interrupts enormous short circuit currents without noise,flame,gas or smoke.

The drawbacks of fuse are that time is lost in rewiring or replacing of fuse in series cannot be obtained unless there is considerable difference in the relative sizes of the fuse concerned.

The function of a fuse wire is

1.To carry the normal working current safely without heating

2.To break the circuit when the current exceeds the limited current.

The material used for a fuse wire must be of low melting point,low ohmic loss,high conductivity and free from deterioration.An alloy of lead and tin is used for small current rating fuses and beyond 10A rating circuit copper wire fuses are used .The present trend is to use silver despite its higher cost owing to its inherent advantages

Back up protection Nh-fuse