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Unformatted text preview: gear is generally of metal-clad type. In this type of
construction, all live parts are completely enclosed in an earthed metal casing. The primary object of
this practice is the definite localisation and restriction of any fault to its place of origin. Short-Circuit
Whenever a fault occurs on a network such that a large current flows in one or more phases, a shortcircuit is said to have occurred.
When a short circuit occurs, a heavy current called short circuit current flows through the circuit.
This can be beautifully illustrated by referring to Fig. 16.6 where a single phase generator of voltage
V and internal impedance Z i is supplying to a load Z . Under normal conditions, the current in the
circuit is limited by *load impedance Z . However, if the load terminals get shorted due to any reason,
the circuit impedance is reduced to a very low value ; being Z i in
this case. As Z i is very small, therefore, a large current flows
through the circuit. This is called sho...
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- Spring '12