Glossary · Motion control and drives
Brushless DC motor (BLDC)
Also known as: BLDC motor, Electronically commutated motor (EC motor)
German: Bürstenloser Gleichstrommotor (BLDC)
In electric drives, a brushless DC motor (BLDC) is a permanent-magnet motor in which the commutation of the stator windings is done electronically by a drive, using rotor position feedback or sensorless estimation, instead of by brushes and a mechanical commutator.
- Motion control
In one sentence
A brushless DC motor is a permanent-magnet motor whose windings are switched electronically by a drive instead of by brushes.
Example
Small conveyor rollers and cooling fans in control cabinets often use BLDC motors with integrated electronics and Hall sensors.
How it applies
- Engineering: BLDC motors offer high efficiency and no brush wear. They need a drive that knows the rotor position, typically from Hall sensors, or estimates it sensorlessly from the back-EMF.
- Operation: Because there are no brushes, there is no brush dust and no brush replacement; bearings and electronics remain wear or aging parts.
- Maintenance: Replacing a motor may require re-entering motor data or re-aligning the Hall sensor or encoder offset in the drive.
- Documentation: State which drive or controller the motor is approved with and whether the electronics are integrated. Remove brush-change tasks from maintenance schedules copied from older DC motor documentation.
BLDC vs. PMSM
Both have permanent magnets on the rotor. BLDC usually refers to motors with trapezoidal back-EMF and block (six-step) commutation; a Permanent-magnet synchronous motor (PMSM) has sinusoidal back-EMF and is driven with sinusoidal currents, often with Field-oriented control (FOC). In practice manufacturers use the terms loosely, so check the datasheet.