By Carl Mathie
Updated Mar 24, 2022

How a Brushed DC Motor Works

In a brushed motor, the rotor contains a series of windings—usually arranged as three evenly spaced coils—connected to a commutator. Fixed magnets positioned on the stator provide the opposing magnetic fields that drive rotation. Current is supplied to the windings through conductive brushes that maintain continuous electrical contact as the rotor turns. When the motor is energized, the interaction between the magnetic field generated by the current‑carrying windings and the stator magnets produces a torque that turns the rotor. As the rotor turns, the brushes switch contact from one winding to the next, reversing the current direction and sustaining rotation.

How a Brushless DC Motor Works

A brushless motor reverses the roles of the rotor and stator. The rotor holds permanent magnets, while the stator contains the windings. An external controller energizes the stator windings in a sequence that keeps the magnetic field in opposition to the rotor magnets, producing continuous torque. Because there are no brushes, the system eliminates mechanical contact and relies on electronic commutation, which requires a small controller or microprocessor to synchronize the current pulses.

Benefits of Brushless Motors

Brushless motors offer several advantages:

• Higher efficiency: Without brush friction, electrical energy is converted more directly into mechanical work.
• Lower maintenance: No brushes to replace reduces downtime and wear.
• Reduced heat: Less friction means cooler operation, allowing higher speeds and improved magnetic field stability.
• Longer lifespan: Fewer moving parts translate into fewer failure points.

Benefits of Brushed Motors

Brushed motors still have their place:

• Lower cost: Simpler design and fewer components keep manufacturing and replacement expenses down.
• Ease of control: Direct current can be regulated with simple voltage or PWM techniques without complex electronics.
• Robustness: Proven technology that performs well in rugged, low‑speed applications.

Choosing between brushed and brushless depends on the application’s performance requirements, cost constraints, and maintenance expectations.