RC Hobby Mysteries: What is Brushless Motor?

Have you ever wondered what the mysteries of brushless motors are? How does it work? Why it becomes more and more popular though it was much more expensive than brushed motor? Well come with us on a voyage of discovery.

First, we need to learn about what’s brushed motor and brushless motor.

What’s brushed motor?
Brushed motor is also known as a brushed DC electric motor. It is an internally commutated electric motor designed to be run from a direct current power source. Brushed DC motors have been in commercial use since 1886. So it has a very long history. They can be varied in speed by changing the operating voltage or the strength of the magnetic field.

In a brushed motor, an electromagnet is mounted on a spinning arm, called an armature or rotor. The armature sits between two magnets set in a horseshoe configuration, collectively called the stator. When power is fed to the electromagnet, the arm moves, aligning the north and south poles of the electromagnet with the opposing poles of the stator.

What’s brushless motor?
So you may have a basic knowledge of brushed motor. Then we have a glance of brushless motor. Just as the name implies, there is no brush.

brushless DC motor

The brushless motor turns this design inside out. Magnets are placed on the armature and are surrounded by one or more electromagnets. The current switch is controlled by computer, turning electromagnets off and on by switching the current; the computer can also factor in the motor’s current speed to optimize efficiency, all without the need for brushes.

How it works?
A DC Brushless Motor uses a permanent magnet external rotor, three phases of driving coils, one or more Hall Effect devices to sense the position of the rotor, and the associated drive electronics. The coils are activated, one phase after the other, by the drive electronics as cued by the signals from the Hall effect sensors, they act as three-phase synchronous motors containing their own variable frequency drive electronics.

Brushless DC motors have been used in many applications, particularly devices such as computer hard drives, CD/DVD players and radio control models. Brushless motors are a popular motor choice for model aircraft including helicopters. Also, the brushless motor is also popular among remote control (RC) racing enthusiasts. As it boasts better performance and suffers less wear than brushed motors of similar size; they can provide a great amount of power to RC racers.

See also How to Build a Brushless DC Motor?

If you have any confuse of brushless motor, feel free to contact us.

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