Split phase inductions motor: resistance star induction run
Two winding are connected in parallel to supply to make 1 phase induction motor self-starting. One is main winding and other is staring winding. both these winding are 900 phase shift.
Thus split phase principle makes 1 phase induction motor self-starting. The main winding is highly inductive whereas auxiliary winding is resistive. It can be used in an electric fan, mixer, refrigerator, dryer machine, drilling machine, parching and pressing machines.
A principle of operation
the current flowing in the main winding(I1) lags voltage(V) by 900 as main winding is highly inductive. The current flowing through starting winding (I2) is almost in phase with voltage (V) as this winding is resistive. The fluxes produced by these current is having 900 phase shift. So resultant of flux will be rotating magnetic field which produces starting torque in one direction.
The centrifugal switch connected in series with starter winding gets automatically open circuited when motor speed reaches to 70 to 80% of synchronous speed.
The under running condition auxiliary winding is out circuit. The direction of rotation can be reversed by reserving by reversing the terminals of either main winding or starter winding.