VFD Maintenance – Inspection Procedure
Ensure reliable VFD operation through electrical measurement, cooling system cleaning, and firmware verification.
Electrical Measurement Procedure
- Wear proper PPE before accessing VFD terminals
- Measure and record input voltage and current across all phases
- Calculate voltage/current imbalance (should be within safe limits)
- Measure DC bus voltage if accessible
- Record power factor and THD (if meter available)
Cooling System Inspection
- Shut down VFD and isolate power
- Clean air filters and fan blades
- Clear dust from heat sinks using compressed air
- Verify all cooling fans spin freely
- Ensure ventilation openings are unobstructed
Parameter Verification
- Access VFD parameter menu
- Compare settings with documented values
- Check motor nameplate data, ramp times, and min/max frequencies
- Ensure energy-saving functions are enabled
- Backup all parameters to external memory or tool
Operational Testing
- Start VFD and observe for stable operation
- Monitor acceleration/deceleration behavior
- Run through full speed range (if applicable)
- Listen for noise or signs of vibration
- Verify control signals and BAS integration responses