why motor starting current is High ?

Answer Posted / y.v.vsurya teja

as in the initial conditions the motor is at rest,the speed
of the motor is zero.

using KVL equation,
V=Eb+IaRa,Eb=back EMF
Ia=armature current
Ra=armature resistance
(very small),V=input supply(around 220V dc)
Initially speed=0
implies Eb=0
Ia=(V/Ra) which is very high value,since V is high
and Ra is very small.
Hence starting resistance or 3 point starter
are used.

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