Single-Phase Induction Motors

Single-Phase Induction Motors
The single-phase electric motor 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 obtainable, a design sprockets 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 1 main winding no start winding. This configuration causes a change of the used magnetic field in relationship to the rotor, creating stating torque. Applications consist of supporters and small appliances.

Split-Phase (induction start engine)
Has two models 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 fans, and blowers.

Capacitor-Start
The most common single-phase motor used in industrial applications. It is a modified split-phase electric motor with a capacitor in series with the beginning winding to provide a start boost. Software 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 will be the most reliable single-phase electric motor because no centrifugal starting switch is required. Applications include followers and pumps in HVAC and refrigeration industries.

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