Single-Phase Induction Motors
The single-phase electric motor operates beneath the same principle as the polyphase electric motor, except that the rotating magnetic field effect generated by the stator does not exist until running rpm is reached. Since no beginning torque is offered, a design mechanism is included to begin the motor. These 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 shift of the applied magnetic field in relationship to the rotor, creating stating torque. Applications consist of followers and small appliances.
Split-Phase (induction start motor)
Has two units of stator windings. The “start” windings sit 90 degrees to the “run” windings and shift the magnetic field of the stator, inducing starting torque. Applications include small grinders, small followers, and blowers.
The most typical single-phase motor used in industrial applications. It really is a modified split-stage electric 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.
Uses identical main and auxiliary windings with a capacitor to supply starting torque. They will be the most reliable single-phase motor because no centrifugal beginning chain sprocket switch is required. Applications include fans and pumps in HVAC and refrigeration industries.