Which is better, brushed or brushless DC motor?

Regarding the choice between brushed and brushless motors, there is no absolute "better" or "worse"; it depends on the application. The two types differ significantly in structure and operation.

1. Maintenance and Lifespan

Brushed DC Motor: Due to the constant "intimate contact" and friction between the brushes and commutator, the brushes wear down over time. Therefore, it requires regular inspection and replacement of parts, resulting in a relatively shorter lifespan.
Brushless DC Motor: As the name suggests, it eliminates the easily worn brushes, using electronic control instead. Because there is no physical friction, as long as the bearings are in good condition, it can run almost indefinitely with minimal maintenance.

2. Efficiency and Heat Generation

Brushed DC Motor: Friction generates heat and wastes energy. You can think of it as some of the energy being wasted on "internal friction" during operation, resulting in lower efficiency and a tendency to overheat.
Brushless DC Motor: It is highly efficient, converting more electrical energy into rotational power rather than heat. A machine using a brushless motor will typically run longer on the same battery.

3. Control and Cost

Brushed DC Motor: Its "brain" is very simple; it rotates when directly connected to a power source, and the speed can be controlled by changing the voltage. Because of its simplicity, it is inexpensive.
Brushless DC Motor: It cannot be directly connected to power; it requires a dedicated "controller." This controller is more sophisticated, but it also increases the cost of the entire system and makes the circuitry more complex.

4. Noise and Sparks

Brushed DC Motor: There is a sound of the brushes rubbing during rotation. Due to mechanical contact, subtle electrical sparks may be generated during commutation, which is a potential hazard in some precision or flammable environments.
Brushless DC Motor: It runs very quietly, with almost no noise, and does not generate sparks, giving a very "stable" feeling.