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