AC PG Motor Working Principle

Motor Side Runs on AC supply (usually 220–240V) Uses main winding + auxiliary winding A capacitor creates phase difference for starting 🔹 PG Sensor Side A small magnetic or Hall sensor mounted on the shaft When motor rotates, it generates square-wave pulses These pulses go to the PCB (usually 5V or 12V signal) 🔹 PCB Logic PCB supplies AC to motor Reads PG pulses If pulses stop → PCB shows error / cuts power 3️⃣ AC PG Motor Wire Identification (Typical) Wire Type Function 2 Thick wires AC supply to motor 1–2 Thin wires Capacitor 3 Thin wires PG sensor (Vcc, GND, Signal) ⚠️ Colors vary by brand. 4️⃣ AC PG Motor Testing (Step-by-Step) ✅ A. Resistance Test (Motor Windings) Multimeter → Ohms mode Measure between motor wires Normal readings: 20Ω – 300Ω (depends on motor) ❌ OL or 0Ω → winding faulty ✅ B. Insulation Test (Important) Measure motor wire → motor body Reading should be OL / very high Low resistance → motor leakage (dangerous) ✅ C. Capacitor Test Check capacitor value (µF) Replace if: Bulged Low capacitance Motor hums but doesn’t rotate ✅ D. Direct AC Supply Test ⚠️ Be careful – 230V AC Connect capacitor properly Give AC supply Motor should: Start smoothly No abnormal noise No overheating ❌ If motor doesn’t start → capacitor or winding issue ✅ E. PG Sensor Testing (Very Important) Multimeter → DC Voltage mode Identify PG wires (usually 3 wires) Check Vcc: Should be +5V or +12V DC from PCB Rotate motor shaft by hand Signal wire should: Fluctuate between 0V – 5V (or 12V) Or show pulsing voltage ❌ No change → PG sensor faulty 5️⃣ Common AC PG Motor Faults Problem Cause Motor runs then stops PG signal missing PCB error code PG feedback not detected Motor hums only Weak capacitor No rotation Open winding Slow speed Capacitor or bearing issue 6️⃣ Relation to NTC / PTC (Image 1) PTC: Helps motor start (older designs) NTC: Limits inrush current or temperature sensing Modern AC PG motors mainly rely on capacitor + PG feedback 7️⃣ Simple Conclusion ✔ AC supply → motor runs ✔ Capacitor → starting torque ✔ PG sensor → speed feedback ✔ PCB → controls & protects system If you want, I can also: Draw AC PG motor wiring diagram Explain AC error codes related to PG Show how to test without PCB