Star-Delta starter Introduction: According to electromagnetic induction principle, once a supply is connected to a three phase induction motor a rotating magnetic field will be set up in the stator, this will link and cut the rotor bars which in turn will induce rotor currents and create a rotor field which will interact with the stator field and starts rotating. Of course this means that the three phase induction motor is entirely capable of self-starting. Need of starter: The need for a starter therefore is not, but in case of three phase induction motor starter is to provide smooth starting, to reduce Heavy starting currents, provide overload and no-voltage protection.