This motor consists of two windings namely the main winding and the auxiliary winding or the starting winding.
The main winding is highly inductive the whereas auxiliary winding is resistive.
Working Of Split Phase Induction Motor:
The current flowing through the main winding (I) lags behind V by 90° since the main winding is highly inductive.
The current flowing through the starting winding (Im) is almost in phase with the supply voltage V as this winding is resistive.
The fluxes produced by these currents will be placed at about 90° with respect to each other. And the resultant of these fluxes will be a rotating magnetic field.
Due to the rotating magnetic field, a non-zero starting torque, acting in one direction will be produced.
The centrifugal switch connected in series with the starting winding gets automatically open-circuited when the motor speed reaches about 70% to 80% of the synchronous speed.
After that, the motor rotates only on the main winding. Thus under the running condition, the auxiliary winding remains out of the circuit.
The direction of rotation of the split-phase motor can be reversed by reversing the terminals of either the main winding or the starter winding.
The direction of rotation changes due to the reversal in direction of the rotating magnetic field.
Applications of Split Phase Induction Motor :
The Starting torque of these motors is poor. Hence are preferred for the following applications:
1. Fans and blowers
2. Washing Machines
3. Centrifugal Pumps
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