What happens in the shaded pole starting method according to the displacement?

The shaded pole starting method is primarily utilized in single-phase induction motors, particularly in small, low-power applications such as fans, blowers, desk fans, and toys. This method relies on creating a rotating magnetic field with the help of a shaded pole to initiate motor rotation. Here’s a step-by-step explanation of what happens according to the displacement in the shaded pole starting method:

1. Construction of the Shaded Pole Motor: In the shaded pole induction motor, one side of each pole is wrapped with a short-circuited, copper coil called a “shading coil.” This shaded portion of the pole creates a delayed magnetic field in relation to the unshaded part.

2. Magnetic Field Displacement: When alternating current (AC) is supplied to the stator winding, a magnetic field is produced. This field is divided into two parts due to the presence of the shading coil. The flux in the shaded part of the pole lags behind the flux in the unshaded part because the induced current in the shading coil opposes the change in flux according to Lenz’s law.

3. Creation of a Rotating Magnetic Field: The difference in flux strengths between the shaded and unshaded parts of the pole causes a rotating magnetic field. This field is relatively weak but sufficient to start the rotor turning. The displacement in the magnetic field across the pole, from the unshaded to the shaded part, provides the necessary phase difference that creates a rotating magnetic field