BLDC Fan Motor Replacement — Inverter Outdoor Precision Diagnosis

BLDC = 3-phase direct drive, controlled by inverter board

Check: **Symptoms**: ① Fan stopped → HP trip + outdoor heating. ② Spins low then stops (Hall sensor fail). ③ Vibration/noise (bearing, blade crack). ④ Asymmetric rotation (phase break, electronic ESC damaged). **Check**: ① Multimeter winding (U-V/V-W/U-W each 10-30Ω, within 5%). ② Hall sensor (3 wires, 5V, 0.5-4.5V swing). ③ Inverter board output (PWM waveform via scope). Parts: LG EAU, Samsung DB31 series.

What to do: **Procedure**: ① OFF + 10 min wait (inverter capacitor discharge). ② Remove fan blade (M6 nut). ③ Remove 4 motor mount bolts. ④ Install new + torque 5 N·m. ⑤ Connect inverter board → motor cable (3-phase + 5-wire Hall), match color. **Caution**: don't replace motor only (must match inverter board code). Can't sub with 220V 1-phase. Price: residential 7-13py ≈ ₩80-150k, industrial ₩300k+.