Brushless DC motors are widely used in industrial applications around the world. From the basic classification of motors, there are mainly brushed motors and brushless motors, as well as DC motors and AC motors. As you can imagine, brushless DC motors do not contain brushes and use direct current for driving, which has many unique advantages compared to other types of motors.
However, in addition to these basic concepts, we may still have many questions, such as: What exactly is a brushless DC motor? How does it work? In what fields does it play a role? Next, we will explore these issues in depth.
How a Brushless DC Motor Works
It is often helpful to first explain how a brushed DC motor works, since brushed DC motors have been in use for some time before brushless DC motors came along. The brushless DC motor has a permanent magnet on the outside and a rotating armature on the inside. The stationary permanent magnet on the outside is called the stator. The armature that rotates and contains the electromagnets is called the rotor.
In a brushed DC motor, when current is fed into the armature, the rotor rotates 180 degrees. To keep it spinning, the poles of the electromagnets must flip. This is done by brushes in contact with the commutator, which switch the direction of the current as the rotor rotates, continually flipping the magnetic field and allowing the rotor to complete a 360-degree rotation.
Brushless DC motors, by contrast, are constructed and operate differently. Essentially, they do not require brushes to switch the magnetic field. In a brushless DC motor, permanent magnets are mounted on the rotor, while the electromagnets are located on the stator. An electronic controller (usually controlled by a computer or sensor) energizes the stator windings in a specific sequence, creating a rotating magnetic field that drives the rotor to rotate continuously for 360 degrees.
What is the purpose of the Brushless DC motor?
Brushless DC motors are typically 85% to 90% efficient, while brushed DC motors are less efficient, typically 75% to 80%. Brushed motors have a limited lifespan and can be a safety hazard in certain environments, as the brushes gradually wear out during operation and can generate sparks. Brushless DC motors are quieter, lighter, and have a longer lifespan. Because the current is precisely regulated by an electronic controller, brushless DC motors enable more precise motion control, resulting in more efficient operation and more consistent performance.
Because of these advantages, brushless DC motors are often used in modern devices that require low noise and low heat, especially those that run continuously. These devices may include washing machines, air conditioners, and other consumer electronics. They may even become the main power source for service robots, which need to carefully control force for safety reasons.
Brushless DC motors have several distinct advantages over other types of electric motors, which is why they find their way into so many household items and are likely to be a major factor in the growth of service robots both inside and outside the industrial sector.
