Understanding Brushless DC Motors and Advantages

Understanding Brushless DC Motors and Advantages

What are Brushless DC Motors

Brushless DC motors (BLDC) are popular in various applications due to their excellent controllability and high efficiency. Unlike brushed motors, which rely on physical contact between brushes and a commutator to conduct electricity, BLDC motors use electronic commutation. Current passes through the three-phase windings in the stator, creating a magnetic field that interacts with the permanent magnets in the rotor, causing it to rotate.

Advantages of BLDC Motors

Compared to other motor types, brushless DC motors offer distinct advantages:

1. Efficiency

BLDC motors can continuously maintain maximum torque throughout their rotation. This contrasts with brushed motors, which only achieve peak torque at certain points in the rotation. Even small brushless motors can deliver significant power due to this efficiency.

2. Controllability

Feedback systems allow precise control of the torque and rotation speed in BLDC motors, reducing energy consumption, heat generation, and extending battery life in battery-powered motors.

3. Durability and Reduced Noise Pollution

Without brushes, BLDC motors produce minimal electric noise and wear much less over time compared to brushed motors. Brushed motors generate sparks as brushes contact the commutator, wearing both components down. The absence of this frictional contact in BLDC motors enhances their longevity.

4. Precision Control

BLDC motors are ideal for applications requiring precise control, such as multirotor drones, where each rotor's speed must be adjusted accurately.

Brushed vs. Brushless Motor: Comparing Aspects

1. Cost

Due to more complex circuitry, BLDC motors are generally more expensive than brushed motors. However, decreasing electronics costs, especially in high-volume applications like automotive motors, have reduced this price difference.

2. Efficiency

The friction created by brushes contacting the commutator in brushed motors generates heat and limits speed. BLDC motors, lacking this friction, operate cooler and more efficiently, converting more electricity into power.

3. Torque

The electronics in brushless motors can sense when the motor starts slowing down under load, providing additional power when needed. This is why brushless motors are often preferred for applications requiring high torque.

4. Lifetime

Brushed motors require regular replacement of brushes and suffer gradual wear of the commutator. BLDC motors, with no moving electrical contacts, avoid this issue and generally have a longer operational life.

5. Speed and Acceleration

Brushed motors often have a laminated iron core, increasing rotational inertia and limiting acceleration. In contrast, BLDC motors use strong magnets and have lower inertia, enabling quicker acceleration and deceleration.


Brushless DC motors offer significant advantages over their brushed counterparts in the field of electric propulsion. Their efficient, durable, and precise design makes them ideal for applications like electric bikes and drones, providing optimal control and performance.