venkat reddy said:
what is meant by inrush current
when the transformer is connected to the line at the instant when the supply voltage in the line is zero the transformer demands a flux which is twice that of rated maximum flux.this is called as doubling effect .in order to satisfy this large magnitude of magnetising current is required.the value of the large magnesing current will be in the order of hundred times of the rated current of the promary.this current is called as the inrush current.this current will last for very short duration only i.e about 20msec so no harm what soever to the transformer due to the inrush current.