What is the shaded pole starting method?

The shaded pole starting method is a simple and straightforward technique used to start single-phase induction motors. This method is primarily applied to small motors, such as those found in household appliances (like fans and small pumps) and in various small-scale industrial applications. Here’s a breakdown of how it works and its significant attributes:

1. Design and Principle: In this design, a part of each pole is wrapped by a short-circuited, single-turn copper coil called a “shading coil”. The poles of the motor have a portion, typically about one-third, covered by this copper coil. The presence of these shading coils creates a magnetic flux that is out of phase with the flux in the unshaded portion of the pole. The difference in flux creates a rotating magnetic field necessary for the rotor to start turning.

2. Function: When alternating current (AC) flows through the stator winding, it induces a magnetic field. Due to the shading coil on a portion of the pole, the magnetic flux in the shaded part lags behind the flux in the unshaded part. This lag creates a rotating magnetic field which exerts a torque on the rotor, causing it to start rotating.

3. Characteristics and Limitations: The shaded pole motor is known for its simplicity, reliability, and low cost. It does not require any additional starting mechanisms, making it an economical choice for small appliances. However, the efficiency of shaded pole motors is relatively low, and they