Steps for troubleshooting humming noise in ATV320:

1. Check the noise reduction parameter 'nrd'. Try setting it to Yes and check.
2. Check the parameter Switch Freq Type 'SFt'. Try setting it to HF2 and check.

If these settings does not resolve then check the below points in the installation site:

1. Ensure all components are grounded appropriately.
2. Using a shielded power cable to connect the variable frequency drive to the motor and correctly connecting the shield to drive and motor ground locations.
3. Using motor Choke. If the cables are longer than 50 meter between drive and motor. Check the switching frequency and motor cable length.
4. Using twisted control wiring leads to provide a balanced capacitive coupling.
5. Running power and control wiring separately.

Released for:Schneider Electric India