BLDC Motors

Brushless DC motors use electronic commutation for high efficiency and long life.

Intermediate

A BLDC motor has permanent magnets on the rotor and windings on the stator. An ESC or motor-driver switches the phases based on rotor position — from Hall sensors or sensorless back-EMF detection. Control methods: trapezoidal (six-step) commutation or field-oriented control (FOC) for smooth, quiet torque.

Speed constant $K_v$ (rpm per volt) and torque constant $K_t$ are related: $K_t \approx 9.55 / K_v$ (N·m/A, with $K_v$ in rpm/V).

Uses: drones, EVs, ceiling fans (energy-efficient BLDC fans), computer fans, hard drives and power tools.

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