The correct answer is: D. Universal motor
A universal motor is a type of electric motor that can be powered by both AC and DC electricity. It is commonly used in small appliances such as vacuum cleaners, hair dryers, and tape recorders.
A universal motor has a stator and a rotor. The stator is the stationary part of the motor, and the rotor is the rotating part. The stator has two windings, a main winding and a starting winding. The main winding is connected to the power source, and the starting winding is connected to the power source through a capacitor.
When the power is turned on, the current flows through the main winding and creates a magnetic field. The magnetic field interacts with the rotor, which is made of iron, and causes it to rotate. The starting winding is used to help the motor start rotating. Once the motor is up to speed, the starting winding is disconnected.
Universal motors are efficient and have a high starting torque. They are also relatively small and lightweight, which makes them ideal for use in small appliances.
Hysteresis motors are used in applications where a constant speed is required, such as in clocks and watches. They are also used in some types of electric motors, such as stepper motors.
Reluctance motors are used in applications where a high starting torque is required, such as in electric vehicles. They are also used in some types of electric motors, such as brushless DC motors.
Capacitor-run motors are used in applications where a high starting torque is required, such as in air conditioners and refrigerators. They are also used in some types of electric motors, such as universal motors.