Briefly Describe What Is A BLDC Motor And How Does It Work?

BLDC motors are common in medical, aerospace, industrial automation, electric vehicles, and robotics applications worldwide. For a simple understanding, you may think that the BLDC motor does not contain brushes and uses DC. These motors have many specific advantages over other types of motors, but, beyond the basics, what exactly is a BLDC motor? How does it work and what does it do?

　　Working principle of BLDC motor

　　It often helps to explain how a DC brushed motor works since BLDC motors were used a long time before they became available. A DC brushed motor has permanent magnets on the outside of its structure and a rotating armature inside. The permanent magnets fixed on the outside are called stators. The armature that rotates and contains the electromagnet is called the rotor.

　　In a DC brushed motor, when current flows to the armature, the rotor rotates 180 degrees. To go further, the poles of the electromagnet must flip. As the rotor rotates, the brushes make contact with the stator, which flips the magnetic field and rotates the rotor 360 degrees.

　　The BLDC motor flips from the inside out, eliminating the need for brushes to flip the electromagnetic field. In a brushless DC motor, the permanent magnets are located on the rotor and the electromagnets are located on the stator. The computer then charges an electromagnet in the stator, causing the rotor to rotate 360 degrees.

　　What is the purpose of the BLDC motor?

　　Brushless DC motors are typically 85-90% efficient, while brushed motors are typically only 75-80%. The brushes eventually wear out, sometimes causing dangerous sparks that limit the lifespan of brush motors. Brushless DC motors are quiet, lightweight, and last longer. Because the computer controls the current, brushless DC motors allow for more precise motion control.

　　Due to all these advantages, brushless DC motors are often used in modern equipment requiring low noise and low heat, especially in continuous operation equipment. This could include medical surgical tools, aviation, industrial automation equipment, electric vehicles, robots, washing machines, air conditioners, and other consumer electronics.

　　BLDC motors have several distinct advantages over other types of motors, which is why they have found their way into numerous applications and may gradually become mainstream in the motor market.