Single-Phase Induction Motors

Single-Phase Induction Motors
The single-phase engine operates beneath the same principle as the polyphase electric motor, except that the rotating magnetic field effect produced by the stator does not exist until running rpm is reached. Since no starting torque is obtainable, 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 one main winding and no begin winding. This configuration causes a change of the used magnetic field in relationship to the rotor, creating stating torque. Applications include followers and small appliances.

Split-Phase (induction start motor)
Has two models of stator windings. The “start” windings are positioned 90 degrees to the “run” windings and change the magnetic field of the stator, inducing beginning torque. Applications include small grinders, small followers, and blowers.

Capacitor-Start
The most typical single-phase motor used in chain sprocket industrial applications. It is a altered split-stage motor 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 are the most reliable single-phase motor because no centrifugal starting switch is required. Applications include fans and pumps in HVAC and refrigeration industries.