Why Single Phase Induction Motor Is Not A Self Starting Motor ?
A single phase induction motor is not self starting as a few actions are needed in order for the torque to be produced such that it starts moving. The principle is explained below in brief. There is a stator and a rotor in an induction motor. The rotor has a short circuited winding and is positioned inside the stator. The stator has a rotating magnetic field. For the motor to operate, this rotating field must generate and flux which in turn induces a flow of current in the rotor winding. This current in turn gives rise to a magnetic field in the rotor. This magnetic field spins at the frequency of the rotor current, which is at the same frequency as the stator field. The movement in the motor is a result of the torque generated by the interaction of these two magnetic fields. The stator field and rotor field have a difference in speed and this causes the current to flow. For the motor to rotate, a resultant torque field is needed that rotates only in one direction.
