Brushless DC Fan Working:

Brushless DC Fan-Energy Efficient and Noiseless:

Fans are an integral part of every individual’s life. A Brushless DC Fan so-called BLDC fan come up with a new technology called Brushless DC technology (BLDC) that has been introduced in the fans nowadays.

Traditional ceiling fans run on AC induction motors. But, fans with BLDC technology use Brushless DC motors that cut power consumption by 65% and increase the lifespan of the fans.

Let us discuss in detail the following details about the BLDC Fans.

• What is a BLDC Motor?
• Construction of a BLDC Fan
• Working for BLDC Fan
• Advantages of BLDC Fans

What is a Brushless DC Motor?

BLDC stands for BRUSHLESS DIRECT CURRENT MOTORS. In previous days DC motors have a commutator along with brushes. With the passage of time and new technology, it has become possible to eliminate the brushes from DC motors.

A Brushless Direct Current Motor (BLDC) is an electric motor that is powered by DC electric source. The motor converts electrical energy into rotational (mechanical) energy.

BLDC motor uses an integrated inverter power supply to provide an electrical signal to drive the motor.

How do BLDC motors differ from conventional DC motors?

• Commutation System:

BLDC motors have an electronically controlled commutation system (instead of the mechanical commutation system using brushes.)

• Magnetic System:

Traditional fan motors consist of electromagnets.  BLDC motors contain permanent magnets rather than electromagnets used in induction motors.

 In a BLDC motor, the permanent magnets are put on the rotor that moves around the stator. The permanent magnet contains less heat loss and energy compared to electromagnets.

Construction of a Brushless DC Fan:

Parts of BLDC Motor:

Stator – The stationary object contains Copper windings, which produce magnetic flux when an electric current is passed through it.

Rotor – The rotating object contains permanent magnets.

Shaft – The rod connecting a motor to the application

BLDC Drive– The drive contains control electronics to run the motor in a controlled manner.

Working of a Brushless DC Fan:

The basic construction of brushless-dc consists of a fan blade attached to a permanent magnet rotor that surrounds the electromagnetic coils of the stator and associated control electronics.

The heart of the BLDC fan is the BLDC Drive. The working of the BLDC drive is as follows.

BLDC drive consists of the following equipment.

1. SMPS
2. Micro Controller
3. Inverter

1. SMPS: Switched-Mode Power Supply (SMPS)

The main purpose of an SMPS is to provide regulated, stable power to the BLDC drive. Switched Mode Power Supply circuit which is designed for obtaining the regulated DC output voltage from an unregulated AC voltage. Here SMPS is used to convert ac supply into dc supply.

2. Micro Controller

A microcontroller is used for receiving the input data from Remote control and giving output data accordingly to an inverter.

3. Inverter

An inverter is a power electronic device or circuitry that changes direct current (DC) to alternating current (AC). After receiving a signal from the microcontroller inverter provides a supply to run the motor.

Fan blades are attached to a permanent magnet rotor of the motor to provide wind.

Working of Brushless DC Drive:

BLDC fan working principle is when we turn on the fan the SMPS convert AC supply to DC supply then after Microcontroller receives the input signal from the remote control and accordingly input signal microcontroller sends the signal to the inverter, then after inverter drives the BLDC Motor.

 A closed-loop Microcontroller receives power from the BLDC via an inverter as shown in the below figure.

When the stator coils get a supply from the source, it becomes an electromagnet and starts producing the uniform field in the air gap. Though the source of supply is DC, using inverter switching makes to generate an AC voltage waveform with a trapezoidal shape.

Due to the force of interaction between the Electromagnet stator and Permanent magnet rotor, the rotor continues to rotate. With the switching of windings as High and Low signals, corresponding winding energized as North and South poles. When two same polarities (Ex S & S, N & N) take place on the rotor and stator, magnetic force pushes the rotor to rotational movement.

So for continuous rotation in the rotor, polarity in the stator changes continuously, so every time the same polarity takes place on the rotor and stator, which helps to continuous rotation in the rotor. The permanent magnet rotor with North and South poles aligns with stator poles which causes the motor to rotate.

Advantages of Brushless DC Fans:

A brushless direct-current (BLDC) motor is an advanced electric motor with an electronic commutator system. Prominent advantages of BLDC motor fans over induction motor fans are

• BLDC motor fans do not run via regulators because of their distinct electrical design. They operate on the remote control. Accurate Speed control, with the help of the remote control, can set the speed, timer, and even sleep. This feature makes it convenient to use.

• BLDC motor fans consume low power, making them inverter-friendly and cost-saving machines. 

• BLDC fans use less power than an induction motor fan. BLDC fans consume around 35 Watts, unlike an ordinary fan that consumes about 80 Watts. That proves them the energy-efficient fans.

• Although the cost of BLDC fans is high compared to ordinary fans a BLDC fan is a money saver for the customers as it saves up to Rupees 1000-1500 per year.
• BLDC motor has a longer life span as they do not get heated because of the magnetic fields around the fan, not in the center of the fan. A standard fan gets overheated.

• BLDC fans are silent as compared to a standard fan due to the absence of brushes on the rotor, and the commutation is performed electronically.