Answer / subhas momdal

At the time of switching of a transformer total flux =
transient flux +steady state flux And it is equal to
double the normal flux. As flux is increase two times the
normal, therefore x-mer core will be run dip into
saturation.hence therefore magnetising current taken from
the supply will be too large nearly 50 times of original.
It is known as inrush current of x-mer.

Answer / abhinav garg

nrush current or input surge current refers to the maximum,
instantaneous input current drawn by an electrical device
when first turned on. For example, incandescent light bulbs
have high inrush currents until their filaments warm up and
their resistance increases. Alternating current electric
motors and transformers may draw several times their normal
full-load current when first energized, for a few cycles of
the input waveform. Power converters also feature high
inrush currents relative to their steady state currents.
This is typically the charging current of the input
capacitance. The selection of overcurrent protection devices
such as fuses and circuit breakers is made more complicated
when high inrush currents must be tolerated. The overcurrent
protection must react quickly to overload or short circuit
but must not interrupt the circuit when the (usually
harmless) inrush current flows.

Answer / arijit

if transformer goes to saturation during initial power
cycle, then how its come to normal unsaturated condition?

Answer / ravi_myla

ans 3 is most appro..

Answer / shailendra

inrush current is the intially maximum current drawn in the
transformer.

Answer / chetan & panks

When we charge the Trafo, flux will get generated there,
but when we make get it isolated some flux will remain
there.

Again while we charge the trafo,remaining flux will oppose
the present flux hence high current will get generated,
which is very dangerous for trafo. The current produced as
in above condition is called Inrush Current, which is
flowing for very minor time (i.e. for 4-5 secs)

Answer / prashant

Inrush current is when we charge the x'mer for the 1st time,
the current taken by the x'mer for magnetizing the core and
to produce flux is called inrush current.

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