Shaded Pole Motors: Basics

A Shaded Pole motor is an AC single phase induction motor.

The auxiliary winding, which is composed of a copper ring, is called a shading coil.

The current in this coil delays the phase of magnetic flux in that part of the pole in order to provide a rotating magnetic field.

The direction of rotation is from the unshaded side to the shaded ring.

Basic principles of Shaded Pole Motor

This shading-coil (ring) arrangement displaces the axis of the shaded poles from the axis of the main poles

When power is applied to the stator, the flux in the main part of the pole induces a voltage in the shading coil, which acts as a transformer secondary winding.

Since the current in the secondary winding of a transformer is out of phase with the current in the primary winding.

The current in the shading coil is out of phase with the current in the main field winding.

Thus, the flux of the shading pole is out of phase with the flux of the main pole.

Rotating field of a Shaded Pole Motor

Rotating field of a Shaded Pole Motor