What is the Need to Use Brushless DC Motors?

Motor is the most important part of any electro-mechanical motion control system, marking the performance of the machine. In 1960, the Brushless DC Motors were introduced to add a spark to the machine performances like never before, and since then they started to replace and override traditional brushed motors (around since the 1800s), because of the benefits they offer through their usage.

In comparison to the brushed motors brushless DC motors have the benefits of being more efficient, suffering less mechanical wear, producing a lower level of EMI, lasting longer with greater reliability.

Performance wise, superior speed versus torque, high dynamic response, and a greater range of speeds became the reason they succeeded in marking better machine performances and became preferred choices of users in a number of industries, including aerospace, medical instrumentation, automation, and many others.

Understanding the difference between brushed and brushless DC motors is important and of great help for any motion control expert. Most commonly used Brushed motors have now been replaced by their brushless counterparts. As a user you only need to choose the right DC motor for best performance.

Difference between Brushed and Brushless DC Motors: The physics of a brushed DC motor is a configuration of wound wire coils, the armature, acting as a two-pole electromagnet. The commutator, a mechanical rotary switch, reverses current’s directionality twice per cycle.

As a result of which the current flows through the armature, thus pulling and pushing the electromagnet’s poles against the permanent magnets along the outside of the motor. The polarity of the armature’s electromagnet is then reversed by the commutator, as its poles cross the permanent magnets’ poles.

A brushless motor, by contrast, utilizes a permanent magnet as its external rotor. Along with that, three phases of driving coils and a specialized sensor tracking rotor position are also used by it. After tracking the rotor position, sensor sends out reference signals to the controller. In turn, the coils are activated in a structured way – one phase after the other, by the controller.

Advantages of Brushed and Brushless DC Motors:

Brushed

  • Overall low construction costs;
  • Rebuilding option available to extend life;
  • Controller is simple and inexpensive;
  • No need of controller for fixed speed;
  • Best suitable for extreme operating environments.

Brushless

  • No brushes so less overall maintenance;
  • Effective Operation at all speeds with rated load;
  • Efficiency and output power are high to size ratio;
  • Reduced size feature with far superior thermal characteristics;
  • Higher speed range and lower electric noise generation.

Brushed and brushless DC motors are both used in variety of applications. Frequent use of Brushed DC motors can be seen in household appliances and in automobiles.

Their ability to alter the torque to speed ratio exclusive to brushed motors, aids them in maintaining a strong industrial niche. But still brushed motors are unable to beat brushed motors.

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