The correct answer is: A. universal motor

A universal motor is a type of electric motor that can run on either AC or DC power. It is a small, lightweight motor that is often used in appliances such as vacuum cleaners, drills, and power tools.

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 field winding. The main winding is connected to the power source, and the field winding is connected to a commutator.

The commutator is a device that switches the current between the two windings of the rotor. This switching action creates a rotating magnetic field in the rotor. The rotating magnetic field interacts with the stator’s magnetic field, and this interaction produces a torque that causes the rotor to rotate.

The speed of a universal motor can be controlled by changing the voltage applied to the motor. The higher the voltage, the faster the motor will rotate.

Universal motors are efficient and reliable motors that are well-suited for a variety of applications.

Here is a brief explanation of each option:

• A. universal motor
  A universal motor is a type of electric motor that can run on either AC or DC power. It is a small, lightweight motor that is often used in appliances such as vacuum cleaners, drills, and power tools.

• B. single phase induction motor
  A single phase induction motor is an electric motor that uses a single phase of alternating current to produce a rotating magnetic field. Single phase induction motors are the most common type of electric motor, and they are used in a wide variety of applications, including fans, pumps, and compressors.

• C. two phase induction motor
  A two phase induction motor is an electric motor that uses two phases of alternating current to produce a rotating magnetic field. Two phase induction motors are more efficient than single phase induction motors, and they are used in a variety of applications, including industrial motors, elevators, and cranes.

• D. three phase induction motor
  A three phase induction motor is an electric motor that uses three phases of alternating current to produce a rotating magnetic field. Three phase induction motors are the most efficient type of electric motor, and they are used in a variety of applications, including large industrial motors, power generation, and traction motors.