Single-Phase Induction Motors

Single-Phase Induction Motors
The single-phase engine operates beneath the same principle as the polyphase engine, except that the rotating magnetic field effect produced by the stator will not exist until running rpm is reached. Since no beginning torque is available, a design system is included to begin the motor. They are the various designations:

Torque-Speed Curves of Different Single-Phase Induction Motors

Shaded-pole: Have only one main winding and no begin winding. This configuration causes a change of the applied magnetic field in relationship to the rotor, creating stating torque. Applications include followers and small appliances.

Split-Phase (induction start chain sprocket 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 starting 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 engine with a capacitor in series with the start 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 necessary. Applications include supporters and pumps in HVAC and refrigeration industries.