Brushless DC motors are common in various applications across the world. At the most basic level, there are brushed and brushless motors and there are DC and AC motors. Brushless DC motors, as you may imagine, do not contain brushes and use a DC current. These motors provide many specific advantages over other types of electrical motors, but, going beyond the basics, how do brushless DC electric motors work?
What is a brushless DC motor?
Brushless DC electric motors (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous motors that are powered by a DC electric source via an integrated inverter/switching power supply. Efficiency is a primary selling feature for BLDC motors. Because the rotor is the sole bearer of the magnets, it requires no power, i.e., no connections, no commutator, and no brushes. In place of these, the motor employs control circuitry. To detect where the rotor is at certain times, BLDC motors employ, along with controllers, rotary encoders or a Hall sensor.
ZHAOWEI designs, develops and manufactures a series of small brushless DC motors varying from 3V to 24v brushless DC motor.
How do brushless DC electric motors work?
The brushless DC motor is composed of the motor body and the brushless DC motor driver. The stator of the brushless DC motor is the coil winding armature and the rotor is the permanent magnet. If electrified with a fixed DC, the motor can produce the constant magnetic field and can’t rotate. When the rotor position is being detected in real time, the stator can generate a rotating magnetic field with a uniform change in direction according to the position of the rotor which makes it possible to offer the corresponding current. In this way, the motor can rotate following the magnetic field. Actually, with a BLDC motor, it is the permanent magnet that rotates. To control the rotation, you adjust the magnitude and direction of the current into these coils.
Also, if the brushless DC-motor is integrated with a brushless DC motor controller, it will combine the advantages of brushless DC motors and their electronic control. Controller settings can be configured in combination with motion manager via programming adapters.
Brushless DC electric motors have several kinds of advantages owing to the working principle.
2.1 One big advantage is efficiency, as these motors can control continuously at maximum rotational force (torque). Brushed motors, in contrast, reach maximum torque at certain points in the rotation. Brushless DC electric motors typically have an efficiency of 85-90%, while brushed motors are usually 75-80% efficient. Brushless DC motors with planetary gearheads can provide higher torque.
2.2 The second big advantage—related to the first—is controllability. BLDC motors can be controlled, using feedback mechanisms, to deliver precisely the desired torque and rotation speed. Precision control, in turn, reduces energy consumption and heat generation, thus lengthening the service life.
2.3 Brushless DC motors are quiet, lighter and have much longer lifespans, thanks to the lack of brushes. With brushed motors, the brushes and commutator wear down as a result of continuous moving contact, and also produce sparks where contact is made. Electrical noise, in particular, is the result of the strong sparks that tend to occur in the areas where the brushes pass over the gaps in the commutator. When comparing Brushless VS Brushed Motor, you may know this is why BLDC motors are often considered preferable in applications where it is important to avoid electrical noise.
What are they good for?
We’ve seen that BLDC motors offer high efficiency and a strong ability to control and that they have a long operating life. Actually, in many applications, brushless DC electric motors alone are not enough. Planetary gearheads also play an important role.
Brushless DC gear motors are often used in modern devices where high torque, low noise and long service life are required. Brushless DC motor assembled with gear motor, which is widely used in massage machines, fitness equipment, robotic equipment, speakers, vacuum cleaners, etc. Here are some of the solutions provided by ZHAOWEI that have been gaining more and more popularity: