Single-Phase Induction Motors
The single-phase electric motor operates under the same principle as the polyphase electric 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 available, 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 change of the applied magnetic field in relationship to the rotor, creating stating torque. Applications consist of fans and small appliances.
Split-Phase (induction start motor)
Has two pieces of stator windings. The “start” windings are positioned 90 degrees to the “run” windings and change the magnetic field of the stator, inducing chain sprocket beginning torque. Applications include little grinders, small enthusiasts, and blowers.
Capacitor-Start
The most common single-phase motor used in industrial applications. It is a altered split-phase motor with a capacitor in series with the beginning winding to supply a start boost. Program include small conveyors, large 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 electric motor because no centrifugal starting switch is necessary. Applications include supporters and pumps in HVAC and refrigeration industries.