How brushed and brushless DC motors work, their pros and cons, and how their maintenance needs compare.
Direct current (DC) motors convert electrical energy into mechanical energy and use a mechanism that periodically reverses current flow. Their speed can be controlled over a wide range by varying voltage or current.
- Brushed motor: works with a commutator, stationary magnets and rotating electromagnets. It is cheap to make, reliable and easy to control, but graphite brushes and the commutator need regular service and life is short under heavy use.
- Brushless motor: the rotor carries permanent magnets; a controller converts DC to AC and tracks rotor position with Hall sensors. It is long-lived, maintenance-free and efficient, but costlier to build and needs a more complex controller.
Brushed motors date back to the 19th century, while brushless DC motors only became practical with semiconductors in the 1960s.