Brushed vs Brushless DC Motors: What's the Difference?

Every DC motor converts electrical energy into mechanical motion, but brushed and brushless motors take distinctly different approaches to this task. Understanding these differences helps you choose the right motor for your application.


How Each Type Works

Brushed DC motors use a simple but effective design. The core rotating component (rotor) contains electromagnets powered through a mechanical commutator - a segmented copper cylinder. Carbon brushes press against this commutator to deliver power, automatically switching current direction as the motor spins. This switching action keeps the motor rotating by continuously changing magnetic fields.

Brushless motors flip this arrangement around. The permanent magnets mount on the rotor while the electromagnets stay fixed in the outer shell (stator). Instead of mechanical brushes switching the current, an external controller has to provide AC power at a specific frequency and phase to the coils to keep the motor rotating.

Related Post: How To Control A Linear Actuator With Arduino

Performance and Characteristics

The differences between brushed and brushless motors lead to distinct performance characteristics that make each type better suited for certain applications.

Power Delivery

Brushed motors deliver power through physical contact between brushes and the commutator. This creates some friction and means the brushes eventually wear out, but offers simple, reliable control - just apply DC voltage. The direct power delivery makes them excellent for low-cost applications requiring consistent force or torque.

Brushless motors deliver power through electromagnetic fields without physical contact. While this eliminates brush friction, it requires more complex electronic control systems, adding cost and complexity to the system.

Speed and Control

Brushed motors provide excellent torque characteristics and simple speed control. Their straightforward design makes them ideal for applications where reliable, consistent performance matters more than ultimate efficiency.

Brushless motors operate without mechanical switching, which can allow for higher top speeds in some applications. However, their electronic control requirements make them more complex to implement and potentially more costly to repair.

Durability and Maintenance

Brushed motors have internal components (brushes) that wear out. In large brushed motors, the brushes are often replaceable, and are considered maintenance items. With small-scale brushed motors, it is often not practical to replace the brushes. That said, in properly designed systems, brushes can last hundreds to thousands of hours, and replacement is typically straightforward and inexpensive.

Brushless motors have fewer wearing parts but rely on more complex electronics. While they don't need brush replacement, repairs often require specialized knowledge and components. By not relying on sacrificial brushes, brushless motors can thus be expected to last much longer.

Related Post: What is Duty Cycle?

Practical Applications

Both motor types find extensive use across various industries and applications.

Common Brushed Motor Applications

  • Linear actuators and motion control systems
  • Power tools and equipment
  • Automotive systems
  • Industrial machinery
  • Robotics and automation
  • Medical equipment
  • Prosthetics
  • Consumer appliances

Common Brushless Motor Applications

  • High-speed cooling fans
  • Computer hardware
  • Drones and RC equipment
  • Specialized industrial equipment

Understanding Trade-offs

Both motor types have legitimate advantages. Brushed motors offer simple, reliable operation, straightforward control systems, lower initial cost, excellent torque characteristics, and a proven track record in many applications.

Brushless motors shine in their long service life and while they can offer some performance advantages, the added complexity and cost often make brushed motors the more practical choice for many applications. The key is matching the motor type to your specific needs rather than assuming newer technology is always better.

When selecting a motor type, consider your actual requirements rather than focusing on theoretical advantages. Factors like control simplicity, cost constraints, and performance needs should guide your decision.

Brushed vs Brushless Motors FAQ

What are the main differences between brushed and brushless motors?

The key difference lies in their design and power delivery. Brushed motors use mechanical commutators and carbon brushes for power delivery, with electromagnets on the rotor. Brushless motors have permanent magnets on the rotor and electromagnets in the outer shell, using electronic controllers instead of physical brushes. This fundamental difference affects their performance, maintenance requirements, and control systems.

Which type of motor lasts longer?

Brushless motors typically have a longer service life because they don't have wearing components like brushes and commutators. While brushless motors rely on more complex electronics, their lack of mechanical wear points generally results in extended operational life compared to brushed motors.

Are brushless motors always better than brushed motors?

No, brushless motors aren't always better. While they offer longer service life and potentially higher speeds, brushed motors often provide advantages like simpler control systems, lower initial cost, and excellent torque characteristics. The best choice depends on your specific application requirements, budget constraints, and control needs.

Can I replace brushes in a brushed motor?

In large brushed motors, brushes are often replaceable and considered maintenance items. However, in small-scale brushed motors, brush replacement may not be practical. When properly designed, brushes can last hundreds to thousands of hours, and in systems where replacement is possible, it's typically a straightforward and inexpensive process.

Which motor type is easier to control?

Brushed motors are generally easier to control. They operate with simple DC voltage application and don't require complex control systems. Brushless motors, while offering certain performance advantages, need more sophisticated electronic controllers to manage power delivery and motor timing, making them more complex to implement and control.

Making the Right Choice for Your Application

Whether you choose a brushed or brushless motor depends entirely on your specific application requirements. Both technologies have their place in modern engineering, and understanding their differences is key to making the right choice.

If you need guidance in selecting the right motor for your application, our team is here to help. We can assist you in evaluating your needs and finding the perfect solution for your project.