Final answer:
The shaded pole motor operates on electromagnetism principles, using shaded poles to create a rotating magnetic field that drives the motor. It converts electrical energy to mechanical work, has a low starting torque, and is commonly used in low-power applications.
Step-by-step explanation:
The principle and operation of a shaded pole motor involves the basic concept of electromagnetism. In simple terms, when current passes through loops of wire in a magnetic field, a torque is generated on the loops, which results in the rotation of a shaft and thus transforms electrical energy into mechanical work. A shaded pole motor is a type of single-phase induction motor which is widely used for its simplicity and low cost. They typically have a low starting torque and are used in applications where high torque is not required, such as in small fans or clocks.
Operation of a Shaded Pole Motor
Shaded pole motors have a unique construction where part of each pole is wrapped by a short-circuited, single turn of copper wire, called the shading coil. When AC power is applied to the winding, the magnetic field in the shaded part of the pole lags behind the field in the unshaded part due to the induced currents in the shading coil. This creates a rotating magnetic field which is necessary for the rotor to turn. As the rotor begins to rotate, it encounters less opposition from the shaded coils, resulting in the continuous rotation of the rotor.
The phenomenon that occurs in electric motors, namely the creation of a back emf, also applies to shaded pole motors. Lenz's law indicates that the self-generated emf opposes changes in current, thus opposing the input emf. When the motor is under load and slows down, the back emf reduces, allowing more current to flow, and thereby increasing the motor's torque to meet the demand.
The commutator and brushes usually found in other types of motors are absent in shaded pole motors, which makes them more durable and less noisy. However, their efficiency is lower compared to other motors, which limits their use to applications requiring less power.