# Why motor take heavy current at starting?

Why motor take heavy current at starting?

When 3 phase supply is given to the stator of an induction motor, magnetic field rotating in space at synchronous speed is produced. This magnetic field is cut by the rotor conductors, which are short circuited. This gives to induced current in them. Since rotor of an induction motor behaves as a short circuited secondary of a transformer whose primary is stator winding, heavy rotor current will require corresponding heavy stator balancing currents. Thus motor draws heavy current at starting

## Related questions

What are the methods to reduce the magnitude of rotor current (rotor induced current) at starting?
Last Answer : By increasing the resistance in the rotor circuit by reducing the magnitude of rotating magnetic field i.e. by reducing the applied voltage to the stator windings ...

Why squirrel cage induction motors are not used for loads requiring high starting torque?
Last Answer : Squirrel cage motors are started only by reduced voltage starting methods which lead to the development of low starting torque at starting. This is the reason why squirrel cage induction motors are not used for loads requiring high starting torque. ...

Why is the starting current high in a DC motor?
Last Answer : In DC motors, Voltage equation is V=Eb-IaRa (V = Terminal voltage, Eb = Back emf in Motor, Ia = Armature current, Ra = Armature resistance).At starting, Eb is zero. Therefore, V=IaRa, Ia = V/Ra ,where Ra is very less like 0.01ohm.i.e, Ia will become enormously increased. ...

What are the effects of increasing rotor resistance in the rotor circuit of a 3-phase induction motor as starting?
Last Answer : Due to addition of resistance in rotor circuit by the stator not only reduces the staring current, in addition to that the starting torque developed than those given by DOL starting....