Answer / anthony

The inrush current is that value of current used to
overcome the inertia presented by the magnetic dipoles to
the impinging flux . The dipole resists the change in the
turning moment produced by the mag. field ( when machine is
started from rest state).
The jerk current is that value of current that is
drawn in excess of the already supplied current while the
machine is still in operation.
The jerk current is not required to oppose the moment
offered by the magnetic dipole , whereas the inrush current
is used to induce magnetism in a metal and hence overcomes
the dipole moment .
This is the striking diff. between the inrush current
and the jerk current

Answer / s s nanal

In case of AC Motor Inrush current is current drawn by
motor while at start.This inrush current is very high (
almost 5 -6 times full load current.) The reason is,at
start the back emf offerred is zero.This back emf is
developed as the rotor gains speed.Hence at start Current
drawn by motor is equal to Voltage divided by impedance of
stator winding( winding impedance is very low,hence
starting current is high.) Once the rotor gains speed
current drawn by motor is equal to Voltage- Back emf/
impedance.As back emf is developed now the motor draws less
current.

Jurk Load is current drawn by motor already running.But due
to jurk load motor draws high current in order to maintain
speed ( near synchronous speed)

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