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