Single-Phase Induction Motors
The single-phase motor operates under the same principle as the polyphase electric motor, except that the rotating magnetic field effect produced by the stator will not exist until running rpm is reached. Since no starting torque is available, a design mechanism is included to start the motor. These are the various designations:
Torque-Speed Curves of Different Single-Phase Induction Motors
Shaded-pole: Have only 
1 main winding and no start winding. This configuration causes a change of the applied magnetic field in relationship to the rotor, creating stating torque. Applications include fans and small appliances.
Split-Phase (induction start motor)
Has two sets of stator windings. The “start” windings sit 90 degrees to the “run” windings and shift the magnetic field of the stator, inducing beginning torque. Applications include little grinders, small followers, and blowers.
Capacitor-Start
The most Single Phase Induction Motor common single-phase motor used in industrial applications. It is a modified split-phase engine with a capacitor in series with the start winding to provide a start boost. App include small conveyors, large blowers, pumps, and direct-drives.
Permanent-Split-Capacitor (PSC)
Uses identical primary and auxiliary windings with a capacitor to supply starting torque. They will be the most reliable single-phase engine because no centrifugal beginning switch is required. Applications include supporters and pumps in HVAC and refrigeration industries.
