The stator of a A.C single phase capacitor start motor has two windings – running winding & starting winding. A capacitor and a centrifugal switch are connected in series with the starting winding. A squirrel cage rotor is fitted in this motor. Capacitor creates 90° phase difference between the two windings.
Single phase current is supplied and the development of rotating magnetic field makes the rotor to rotate. When the rotor attains 70% of the total speed, the centrifugal switch disconnects the starting winding. This motor has high starting torque. The direction of rotation can be changed by just changing the connection of terminals of any one of the windings. The motors find extensive use in wet grinders, small grinding machines, drilling machines, compressor motors used for air -conditioners and refrigerators.