The difference between brushless DC and brushed DC motors

The difference between brushless DC and brushed DC motors

There are different types of DC motors with different speeds, torques, and applications. Generally, DC motors can be divided into brushed and brushless DC motors. Both types are used in commercial and household applications. What is the difference between these motors? What are the advantages of these motors with each other? Let us have a detailed understanding of the DC motor together. 

Introduction to DC Motor

Electric motors have become an indispensable part of our lives. We can find electric motors in most equipment, whether it’s electric cars, robots, drones, or appliances. The electric motor is useful when the output needs to rotate. A DC motor is a motor whose input current is DC.

Dc motor can be divided into a brushless DC motor and a brushed DC motor according to the structural differences.

Although they work in the same way, they differ in structure, performance characteristics, and control.

DC Motor

Working principle of DC motor

DC motors work based on simple electromagnetic principles. “When placed vertically in a magnetic field, the current-carrying conductor will receive a force, the direction of which is perpendicular to the current-carrying conductor and the direction of the magnetic field.” Now, we will study the structural differences between brushed and brushless DC motors and how these differences play a vital role in their advantages.

Structural differences between brushless DC motor and brushed DC motors

The brushed DC motor is the simplest and earliest one. Brushed DC motors are composed of armature windings, stator commutators, permanent magnets or electromagnets, and brushes. The rotor is enclosed inside the stator. The stator of the DC brushed motor also contains permanent magnets or electromagnets. The brushes consist of carbon, and when the shaft rotates, they contact the commutator. When the armature coil is aligned with the north and South poles of the stator, the role of the commutator is to reverse the current direction. A commutator changes current polarity by supplying itself with a power source and rotating the current. This reverse current phenomenon is also known as mechanical reversing.

The working principle of brushless DC motors is the same as that of brushed DC motors, but their structure is different. In a brushless DC motor, the stator contains coil windings made of slotted laminated steel, and the rotor is equipped with permanent magnets. That means that the stator as the rotating part of the brushless DC motor is fixed in the brushless DC motor, while the permanent magnet is fixed in the brushless DC motor as the rotor. The brushless DC motor also has no mechanical commutator or carbon brush. 

The switching of a brushless DC motor is much more complicated than that of a brushed DC motor, so it is electronically using electronic components. These electronic components usually place the sensor along the magnetic poles. These sensors provide feedback to the control center, which helps estimate the rotor position. There are three algorithms for sensor-based commutation: sinusoidal commutation, trapezoidal commutation, and vector control or field control.

The above discussion explains the difference in principle and structure between brushless and brushed DC motors. Now, based on these differences, we will find some unique advantages that these motors offer.

brushless DC motor and brushed DC motors

Comparison of brushless and brushed DC motor characteristics

Brushed DC motors are cheap, reliable, and have a high torque inertia ratio. Brushed DC motors are suitable for working under harsh conditions. But the disadvantage of a brushed DC motor is that because the continuous contact brush will wear out over time, it needs to be cleaned or replaced regularly. Therefore, if the application requires a long service life and requires maintenance after some time, a brushed DC motor is not a wise choice.

Compared with the brushed DC motor that does not require any controller, the drive of the brushless DC motor is complicated because of the need for a controller. Due to the complexity of the design, the cost of brushed DC motors increases and makes them more expensive than brushless DC motors. The brushed DC motor can also be connected to the Arduino controller, but it is complicated to connect the brushless DC motor to the Arduino controller. In contrast, brushless DC motors use an electronic speed controller as the interface to the microcontroller.

Moreover, the maximum speed of a brushed DC motor is low, which limits its applicability. The heat dissipation of brushed DC motors is also poor. In contrast, brushless DC motors do not generate heat because there are no sliding parts in brushless DC motors, and the heat generated inside the rotor is dissipated by the larger motor housing of the brushless DC motors, and they have no friction and can be Provide better performance. Compared with brushed DC motors, brushless motors have better performance and higher efficiency. Besides, the maintenance cost of the brushless DC motor is low, and there are no worn brushes.

brushless DC motor and brushed DC motors

Summary 

Both brushless and brushed DC motors are used in the industry. If we do not take the efficiency and maintenance into consideration, brushed DC motors are the first choice. On the other hand, brushless DC motors have a higher initial cost but are much easier to maintain than brushed DC motors. Here, we recommend Kinmore Motor to you. We focus on the production of brushed DC motors and provide you with better power solutions.

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