Shaded Pole Motor

A shaded pole motor is a type of single-phase induction motor that does not use a centrifugal switch. It is commonly used in low-power applications such as fans, blowers, and small pumps.

Construction:
1. Stator: The stator of a shaded pole motor consists of a laminated core with evenly spaced slots. These slots are used to hold the copper windings.
2. Rotor: The rotor is a cylindrical structure made of laminated iron. It is placed inside the stator and is not physically connected to any external power source.
3. Shading Coils: The stator slots are partially covered with copper or aluminum bars, known as shading coils. These coils create a magnetic field imbalance, which is responsible for starting the motor.

Working Principle:
1. When the motor is connected to the power supply, an alternating current flows through the stator windings, creating a rotating magnetic field.
2. The rotating magnetic field induces eddy currents in the shading coils, which in turn creates a magnetic field.
3. The magnetic field produced by the shading coils lags behind the rotating magnetic field of the stator. This time lag creates a rotating magnetic field, resulting in the rotation of the rotor.
4. As the rotor rotates, it carries the load and continues to rotate in the same direction until the power supply is disconnected.

Advantages of Shaded Pole Motor:
1. Simple Construction: Shaded pole motors have a simple and robust construction, making them cost-effective and reliable.
2. Low Cost: These motors are relatively inexpensive compared to other types of single-phase motors.
3. Low Starting Torque: Shaded pole motors have low starting torque, making them suitable for light load applications.
4. Compact Size: Shaded pole motors are compact and lightweight, making them suitable for applications with space constraints.

Conclusion:
In conclusion, the shaded pole motor does not use a centrifugal switch. It relies on the time lag created by the shading coils to start and rotate the motor. This type of motor is commonly used in low-power applications where cost-effectiveness and simplicity are important factors.