Skip to content
English
Contact us
  • There are no suggestions because the search field is empty.

Fan Troubleshooting (3 PH Motor)

The steps and information provided above are intended as general guidelines only. They are not a substitute for professional advice or service. We do not accept any responsibility or liability for any issues, damages, injuries, or losses that may result from following these steps. All electrical work should be performed by a qualified and licensed professional in accordance with local codes and safety regulations.

Power Supply & Wiring Check (Perform with power off!)

  1. Terminal Connections
    1. VFD output terminals
    2. Branch junction boxes
    3. Fan power terminals

      Check the terminals to ensure a proper connection. Ensure no loose connections or signs of burning and/or oxidation

  2. Cable Inspection
    1. Check cables for any visible damage
      1. Crushed, cut, etc.
    2. Continuity/Insulation test

 

Voltage Measurement at Fan Terminals (VFD running – WARNING: High Voltage)

  1. Measurement Points
    1. L1 – L2 ≈ 380V or close to VFD output
    2. L2 – L3 ≈ 380V or close to VFD output
    3. L1 – L3 ≈ 380V or close to VFD output

    Voltage Balance: All three phases within ±10% of each other 

 

Functional Swap Test (Recommended)

  1. Disconnect signal from a working fan, connect to faulty fan (keep power wiring unchanged)
    1. Fan starts working → Power side likely OK, issue in signal cable or VFD output
    2. Fan still not working → Problem likely with fan or its power input

 

Motor Winding Resistance Check (Power OFF)

  1. Use a multimeter to measure resistance between the following wire pairs (in ohms):
    1. Brown – Red: Similar, low resistance
    2. Red – Orange: Similar, low resistance
    3. Brown – Orange: Similar, low resistance

Normal: All three readings are close and low (typically a few ohms)

One phase open (infinite): Likely a burned-out winding

One phase significantly higher resistance: Possibly single-phase damage