# Inrush currents

 What is inrush current and how to calculate it? asked 12/25/2012 baburaman2

 Inrush current is the phenomenon observed only while switching on electro-magnetic equipments like motors & transformers. It is the current required to magnetise the core of such equipment. The magnitude & duration of such magnetising inrush current would depend upon many factors such as type & size of the equipment, the residual magnetism present in the core of the equipment during energisation, the point on the voltage wave at the instant of switching, etc.In fact, this is an exhaustive subject of discussion. There are a few good papers in the net on the subject. Do a google search. answered 4/10/2013 EE65 19 It is the instantaneous input current drawn by an electrical device when first turned on. For an example electric motors draw as much as 5 times it's running current at the start up.   Dependent on the device we use and it's load answered 3/1/2013 charith jeewan 2 Inrush current is the current with is seen when an electrical device is switched on. Typically it is a result of the inductance or charging of capacitors in an electrical system. The magnitude of any inrush current is dependent on the equipment you are talking about and the system parameters. answered 1/8/2013 Steven McFadyen 246

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