Correct option is B
· A shaded pole induction motor is a type of single-phase induction motor with an unsymmetrical magnetic field. This motor has a special construction feature where a small portion of each pole is surrounded by a short-circuited copper ring, known as the shading coil. This shading coil creates a delayed magnetic field in the shaded part of the pole compared to the main part of the pole.
· When alternating current flows through the stator winding, the magnetic field induces a current in the shading coil. Due to the inductive nature of the shading coil, this induced current lags behind the main magnetic field. This phase difference between the main pole and the shaded pole creates a rotating magnetic field, which determines the direction of rotation of the motor.
· The rotation is always from the part of the pole that is not shaded (main pole) to the part that is shaded (shaded pole). This is because the magnetic field in the shaded part is delayed, creating a sequential magnetic effect that causes the rotor to turn in that direction.
· Shaded pole motors are typically used in low-power applications such as fans, small appliances, and toys.
· Their efficiency is relatively low due to inherent design limitations, such as higher losses and lower power factors.
Advantage of shaded pole motor:
· Simple and cost-effective design.
· Self-starting without the need for additional starting mechanisms.
· Suitable for small appliances and devices.
· Low maintenance and high reliability.
