Views: 0 Author: Site Editor Publish Time: 2022-04-11 Origin: Site
The electric motor converts the supplied electrical energy into mechanical energy. Various types of motors are generally used. Among them, brushless DC motors (BLDC) have high efficiency and excellent controllability, and have been widely used in many applications. Compared with other types of motors, BLDC motors have power saving advantages.
This passage is going to talk about the followings of brushless motor:
(1) Why does the brushless motor rotate?
(2) Advantages of brushless motors
(3) Ideal application of brushless motor
As the name suggests, brushless DC motors do not use brushes. For brushed motors, the brushes transfer the current through the commutator to the coil on the rotor. So, how does a brushless motor transfer current to the rotor coil? Not so-because the coil is not on the rotor. In contrast, the rotor is a permanent magnet. The coil does not rotate, but is fixed on the stator. Since the coil does not move, there is no need for brushes and commutators.
For a brushed motor, rotation is achieved by controlling the magnetic field generated by the coil on the rotor, while the magnetic field generated by the fixed magnet remains fixed. To change the speed, change the voltage of the coil. For Brushless motors, permanent magnets are rotating. Rotation is achieved by changing the direction of the magnetic field generated by the surrounding fixed coil. To control the rotation, you can adjust the magnitude and direction of the current flowing into these coils.
A Brushless motor with three coils on the stator will have six wires (two per coil) extending from these coils. In most embodiments, three of these wires will be connected internally, with the remaining three wires extending from the motor body (as opposed to the two wires extending from the brushed motor described earlier). Compared with only connecting the positive and negative terminals of the power unit, the wiring in the Brushless motor housing is much more complicated. Below, we draw conclusions by studying the advantages of Brushless motors.
One big advantage is efficiency, because these motors can be continuously controlled with maximum rotational force (torque). In contrast, brushed motors only reach maximum torque at certain points of rotation. In order for the brushed motor to provide the same torque as the brushless model, a larger magnet is required. This is why even small Brushless motors can provide considerable power.
The second advantage (related to the first advantage) is controllability. The feedback mechanism can be used to control the Brushless motor to accurately transmit the required torque and speed. Precise control can reduce energy consumption and heat generation, and can extend battery life when the motor is powered by a battery.
Due to the lack of brushes, Brushless motors also have high durability and low electrical noise generation. For a brushed motor, the brushes and commutator are worn out due to the contact of continuous movement, and sparks are also generated during contact. In particular, electrical noise is the result of strong sparks easily generated when the brush passes through the commutator gap. This is why Brushless motors are generally considered more desirable in applications where avoiding electrical noise is important.
We have seen that Brushless motorshave high efficiency and controllability, and long service life. So, what are they for? Because of their efficiency and long life, they are widely used in continuously operating equipment. For a long time, they have been used in washing machines, air conditioners and other consumer electronics products. Recently, they have appeared in fans, and their high efficiency greatly reduces power consumption.
They are also used to drive vacuum machines. In one case, a change in the control program caused a significant jump in speed, which is an example of the highest controllability these motors provide.
brushless motors are also used in rotating hard disk drives. Their durability allows the drive to operate reliably for a long time, and its power efficiency helps reduce energy consumption in increasingly important areas.
