When it comes to electric motors, two of the most widely used types are brushless DC motors (BLDC) and brushed DC motors. Both belong to the family of direct current motors, yet they are designed with different architectures and principles of operation. Understanding the difference between these two motor types is essential, whether you are a hobbyist building a drone, an engineer working on industrial automation, or simply someone curious about the technology behind electric vehicles and household appliances.
In this article, we will explore the key differences between BLDC motors and brushed DC motors in terms of design, working principle, performance, efficiency, applications, and much more. By the end, you’ll have a clear picture of which motor type suits different scenarios.
Working Principle
Brushed DC Motor
The brushed DC motor is one of the oldest motor technologies, dating back to the 19th century. Its operation is relatively simple: brushes made of carbon or graphite physically contact a commutator, delivering current to the motor windings. The commutator periodically reverses the current direction, creating continuous torque and rotation.
Brushed motors are still widely used because of their simplicity and low cost. They can be found in toys, household appliances, and low-cost industrial devices. However, their mechanical design comes with limitations, such as brush wear, noise, and reduced efficiency.
Brushless DC Motor (BLDC)
The BLDC motor is a more modern invention, designed to overcome the drawbacks of brushed motors. Instead of brushes and a mechanical commutator, BLDC electric motors use electronic controllers and permanent magnets to achieve commutation. No physical contact is required for commutation, eliminating friction and sparking. In this setup, the rotor usually contains permanent magnets, and the stator has the windings. Sensors or sensorless control algorithms are used to determine rotor position and switch the current electronically.
BLDC motors are now the backbone of many advanced technologies, such as drones, electric vehicles, robotics, and medical devices, thanks to their high efficiency, long lifespan, and superior performance.
Design Structure
The fundamental difference lies in how each motor delivers current to generate motion. This distinction drastically affects their efficiency, lifespan, and maintenance requirements.
Brushed DC Motor
- Rotor: Wound armature connected to the commutator.
- Stator: Permanent magnets or field windings.
- Brushes: Carbon or graphite blocks that physically contact the commutator.
- Commutation: Mechanical.
- Rotor: Permanent magnets.
- Stator: Wound coils.
- No brushes: Instead, sensors and electronic controllers manage switching.
- Commutation: Electronic.
Key Differences
| Feature | Brushed DC Motor | Brushless DC Motor |
| Commutation | Mechanical (brushes + commutator) | Electronic (controller) |
| Efficiency | 75~80% | 85~90%+ |
| Maintenance | High (brush replacement) | Low (no brushes) |
| Noise | Higher (sparks, friction) | Low (quiet, smooth) |
| Lifespan | Shorter | Longer |
| Control Complexity | Simple (voltage control) | Advanced (ESC needed) |
| Size/Power Density | Larger, less efficient | Compact, high power density |
| Applications | Toys, appliances, automotive | EVs, drones, robotics, industry |
Conclusion
While both brushed and brushless DC motors operate on similar electromagnetic principles, their differences in design and operation create significant performance gaps. Brushed DC motors are simple, inexpensive, and easy to control, making them suitable for low-cost, intermittent-use devices. BLDC motors, on the other hand, deliver superior efficiency, reliability, power density, and quiet operation, making them the preferred choice for modern high-performance applications.
The choice between a BLDC motor and a brushed DC motor depends on application requirements. If initial cost and simplicity matter most, brushed motors still hold value. But for long-term performance, energy efficiency, and durability, BLDC motors clearly dominate the future of motion technology.
