ELEC 211 Lecture Notes - Lecture 12: Shaded-Pole Motor, Rotating Magnetic Field, Ampere
Document Summary
A shaded pole induction motor develops the required rotating magnetic field in a different manner from the two coil motors discussed in previous lectures. A shaded pole is a magnetic pole that is physically divided and has its smaller segment surrounded with a short-circuited shading coil. When a single-phase supply is applied to the stator an alternating flux is produced. The changing flux induces emf in the shaded coil. As the shaded portion is short circuited, the current is produced in opposition to main flux. Flux in the shaded pole lags the flux in the unshaded pole, phase difference between these two fluxes produces resultant rotating flux through the rotor, causing the rotor to rotate. The direction of rotation is from unshaded to shaded pole. Simple and robust as no centrifugal switch is required. Low efficiency: copper losses are high due to copper band.
