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24 Nov, 22

What is a Brushless DC Motor, and How Does it Work?


Brushless DC motors have evolved as a more efficient alternative over the brushed counterpart. They enjoy the widespread application in electric vehicles, high-end appliances, hobby aircraft, including multirotor. However, do you know what is a brushless DC motor, and how does it work, and what are the advantages of brushless DC motors? Millennium Semiconductors India Pvt. Ltd., the leading electronic components distributor, answers these questions.

What is a Brushless DC Motor?

On the one hand, where a brushed DC motor comprises a configuration of wound wire calls and the armature that serves as a two-pole electromagnet, on the other hand, a Brushless DC (BLDC) motor uses a permanent magnet as its external rotor. Additionally, it uses three phases of driving coils and a specialized sensor that tracks the rotor position. Let us now proceed to look at the working of a BLDC motor.

How does a Brushless DC Motor Work?

To understand how a BLDC works, we must first look at how a brushed DC motor works. The comparison will help us better comprehend the mechanism of a BLDC.

A brushed DC motor has external permanent stationary magnets (known as stators), and a spinning armature in the interior, comprising an electromagnet termed rotor. The rotor spins 180-degrees when the armature is supplied with electric energy. To proceed, the electromagnet poles should flip. As the rotor spins, the brushes connect with the stator, flip the magnetic field, and enable the rotor to spin completely.

Brushless motors also alternate the polarity of the windings on the interior of the motor. The coil generation results in a magnetic field that exerts a push or pulls force on the permanent magnets arranged on the casing’s exterior. So, in a BLDC motor, it is the external case that rotates and not the motor shaft. The central shaft remains stationary. It enables the supply of power directly to the windings, thus eliminating the need for brushes.

What is the Use of a Brushless DC Motor?

BLDC motors are extensively used across modern devices that demand low heat and noise levels, particularly in devices involving continuous operations. It may include air conditioners, washing machines, vacuum machines, and a range of other consumer electronic products. Additionally, BLDC motors may form the primary source of power for service robots that demand a strong force control to ensure the highest safety levels.

What are the Advantages of a Brushless DC Motor?

As mentioned earlier, BLDC motors have emerged as an efficient alternative over the brushed DC motors. Nevertheless, what are the benefits of a BLDC? Let us see it now.

– High-Efficiency Level: Brushless motors deliver an output equivalent to brushed DC motors but in a comparatively lesser amount of power. Typically, they provide an efficiency of 85-90%.

– Low Wear: In a BLDC motor, the ball bearings form the only physical interface between the rotating exterior of the motor case and the stationary windings on the interior. Such an arrangement refers to a slower wearing out. Besides, BLDC motors are lighter, quieter, and more durable. 

– High Speed: Brushless motors offer lesser friction and a higher operational speed than the brushed motor.

– Higher Precision Motion Control: In BLDC motors, the electrical current is computer-controlled, and hence, you can achieve a higher degree of precision motion control.

Millennium Semiconductors India Pvt. Ltd. is one of the premium semiconductors distributors and electronic components distributors in India. The company is the distributor of a range of high-quality sensors and BLDC motors. 

To know more about Millennium Semiconductors India Private Limited, connect on / 8308838961