Single-Phase Induction Motors

Single Phase Induction Motor single-phase Induction Motors
The single-phase electric motor operates beneath the same principle as the polyphase 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 offered, a design mechanism 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 start winding. This configuration causes a shift of the applied magnetic field in relationship to the rotor, creating stating torque. Applications consist of fans and small appliances.

Split-Phase (induction start electric motor)
Has two pieces of stator windings. The “start” windings sit 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 found in industrial applications. It is a modified split-stage electric motor with a capacitor in series with the start winding to supply a start boost. Application 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 necessary. Applications include followers and pumps in HVAC and refrigeration industries.