Brushless Motor Inner Rotor And Outer Rotor Difference
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Brushless Motor Inner Rotor And Outer Rotor Difference

Views: 0     Author: SDM     Publish Time: 2024-07-19      Origin: Site

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Brushless motor is a common type of motor that is widely used in various fields, such as industrial automation, robotics, drones, etc. Brushless motor is mainly composed of stator, rotor, controller and other parts. In brushless motors, the rotor is divided into two types: internal rotor and external rotor. Below we will introduce the difference between the inner rotor and the outer rotor of the brushless motor in detail.


Structural difference

The main difference between the inner and outer rotors is their position in the motor. The inner rotor is located inside the motor, while the outer rotor is located outside the motor. Specifically, the inner rotor usually consists of a permanent magnet, an iron core, and a rotor shaft, while the outer rotor consists of a coil, an iron core, and a rotor shaft.



1.1 Inner rotor structure


The structure of the inner rotor is relatively simple, mainly composed of permanent magnet, iron core and rotor shaft. Permanent magnets are usually made of rare earth permanent magnet materials, which have high magnetic energy product and coercivity. The iron core is usually made of silicon steel sheet laminated to improve the magnetic flux density of the motor. The rotor shaft is used to support the rotor and transmit torque.


1.2 External substructure


The structure of the outer rotor is relatively complex, mainly composed of coil, iron core and rotor shaft. The coil is usually made of copper wire and is used to generate a magnetic field. The iron core is also made of silicon steel sheet laminated to improve the magnetic flux density of the motor. The rotor shaft is used to support the rotor and transmit torque.


Working principle difference

The working principles of the inner and outer rotors are also different. The working principle of the inner rotor is to use the magnetic field generated by the permanent magnet to interact with the magnetic field generated by the stator, resulting in torque. The working principle of the outer rotor is to use the magnetic field generated by the coil to interact with the magnetic field generated by the stator, resulting in torque.


2.1 Working principle of the inner rotor


The permanent magnet of the inner rotor is subjected to force in the magnetic field generated by the stator, which causes the rotor to rotate. When the rotor rotates to a certain position, the controller switches the direction of the current in the stator coil, thereby changing the direction of the magnetic field, so that the rotor continues to rotate. This working principle makes the inner rotor have high efficiency and stability.


2.2 Working principle of the external rotor


The coil of the outer rotor is subjected to force in the magnetic field generated by the stator, causing the rotor to rotate. Similar to the inner rotor, when the rotor rotates to a certain position, the controller switches the direction of the current in the stator coil, which changes the direction of the magnetic field, so that the rotor continues to rotate. The working principle of the external rotor makes it have high torque and large load capacity.


Performance difference

There are also some differences in performance between the inner rotor and the outer rotor.


3.1 Efficiency


Due to the use of permanent magnets, the inner rotor has a higher magnetic energy product and coercive force, so under the same conditions, the efficiency of the inner rotor is usually higher than that of the outer rotor.


3.2 Torque


Due to the magnetic field generated by the coil, the external rotor has a large load capacity and a high torque. In applications where large torques are required, external rotors are advantageous.


3.3 Volume and weight


Because of its simple structure, the inner rotor usually has a smaller volume and weight. The outer rotor usually has a large volume and weight due to its complex structure.


Application scenario difference

The application scenarios of the inner and outer rotors are also different.


4.1 Application Scenarios of internal rotors


Due to its high efficiency and stability, the inner rotor is usually used in scenes that require high efficiency and stability, such as drones and robots.


4.2 Application Scenarios of external rotors


Due to its large load capacity and high torque, the external rotor is usually used in scenes with high requirements for torque and load capacity, such as industrial automation, cranes, etc.


Analysis of advantages and disadvantages

5.1 Advantages and disadvantages of the inner rotor


Advantages:


High efficiency: Due to the use of permanent magnets, the inner rotor has a higher magnetic energy product and coercive force, and thus has a higher efficiency.

High stability: The working principle of the inner rotor makes it have high stability.

Small size and weight: Due to the simple structure, the inner rotor has a small size and weight.

Cons:


Relatively small torque: The torque of the inner rotor is relatively small compared to the outer rotor.

5.2 Advantages and disadvantages of the external rotor


Advantages:


High torque: The external rotor uses a coil to generate a magnetic field, which has a large load capacity and high torque.

Suitable for high load scenarios: Due to its high torque and load capacity, the external rotor is suitable for high load scenarios.

Cons:


Relatively low efficiency: The efficiency of the outer rotor is relatively low compared to the inner rotor.

Large volume and weight: Due to the complex structure, the outer rotor has a large volume and weight.

In SUMMARY:


There are some differences between the inner rotor of brushless motor and the outer rotor in structure, working principle, performance and application scenario. The inner rotor has high efficiency and stability, which is suitable for the scene that requires high efficiency and stability. The external rotor has a large load capacity and high torque, which is suitable for the scene that requires high torque and load capacity.


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