What type of Motor is Used in a Fan?

fan is a historical machine (still in use) which is used to create a flow within a fluid. These machines namely fans consist of a rotating arrangement comprised of vanes or blades. These vanes or blades act on the fluid or the gas. This rotating system or assembly of blades and the hub is collectively known as a rotor. These also go by the name of an impeller or a runner. Usually, the whole system is contained within some housing or casing.

The fan usually we use are the ones which run on electricity and thus have a mechanism which converts the electrical energy to mechanical work of rotation. Such a device which converts the electrical energy to rotational motion is called a motor. The electric fan use a motor and these are motors which came in various specifications as per the requirement of the fan being designed by the company. As of now there are two types of motors that are used in fans. These are:

  • The BLDC motors or The Brushless DC motors
  • Induction motors

The BLDC motors are very efficient motors and the technology has been in use since quite a notable time but these were not used in fans that are taken in use regularly instead these were used in designing fans of electronic devices or in industries where precision and energy efficiency was must. However, today, cooling fans available online use BLDC motors, making them much more efficient.

The Induction motors have primarily been used in the fans that are used in daily life. These induction motors are less energy efficient as compared to the BLDC motors and are thus being phased out from use. In a fan that uses induction motor for rotational motion the current enters from the wires connected and the capacitor provides the starting torque to the fan. The current enters the coil and thus it magnetises the coil wound around a metal base. There are coils in the stator as well as the rotor. When current enters the stator coil as mentioned above it magnetises it and this in turn induces a current in the rotor coil and this induced current magnetises the rotor coil which interacts with the magnetic field of the stator coil and by Lenz’s law due to formation of poles undergoes repulsion and attraction which causes the rotational motion.

The BLDC motors which have not been in use until recently convert the AC in DC using SMPS and this direct current is used to run the motor. It uses three components to deliver its performance and efficiency. They are:

  • Electronics
  • Rotor
  • Stator

The method of commutation is different in this motor as there are no brushes in this motor thus it uses the driving algorithm of the electronic chip for commutation. Since there are no brushes thus there is no mechanical wear and tear over the period of time and also the permanent magnets reduce the mass power consumption making the motor more efficient. The presence of electronics adds a few other features like the time mode, the sleep mode etc. Overall the fans of BLDC motor save 800-1000 INR/ year for the customer and since these do not have the heating problem thus the life of their core or the coil is much more as compared to the ones using induction motors.