Single Phase Motors • Similar to a 3 phase induction motor with squirrel cage rotor and main stator windgs. Main wndgs Start wndgs Laminated stator slots Rotor Wndgs Centrifugal switch Run (main) and Start (Aux) Windings • The stator has two sets of windgs, Run (which is of thicker size to reduce I²R losses) and Start of thinner size is placed 90˚ apart. • Run has relative Large number of turns. • Aux has relative Small number of turns. Starting Torque in Single phase motor • To produce a starting torque a rotating magnetic field must be produced. • This is done by including the Aux winding. • When an AC source is applied the main windg produce a flux while the Aux wndg produces a flux Since the angles are out of phase a resultant rotating field is created • A centrifugal switch disconnects the Aux. wndg from the supply after it has run up to 75% of full speed. m Φ m Φ aΦ Split Phase Principle . Single Phase Motors • Similar to a 3 phase induction motor with squirrel cage rotor and main stator windgs. Main. relative Large number of turns. • Aux has relative Small number of turns. Starting Torque in Single phase motor • To produce a starting torque a rotating magnetic field must be produced. • This. are out of phase a resultant rotating field is created • A centrifugal switch disconnects the Aux. wndg from the supply after it has run up to 75% of full speed. m Φ m Φ aΦ Split Phase Principle