What does NLP mean on an ATV340 drive, and how do I fix it?

On an ATV340 drive, NLP (No Line Power) indicates that the drive is detecting low or missing input voltage, resulting in insufficient DC bus voltage.

Why this happens:

• The drive is not receiving proper voltage at its input terminals
• The DC bus voltage is too low for normal operation

How to troubleshoot the NLP status:

1. Check input power supply

• Measure voltage at terminals L1, L2, and L3
• Confirm the supply voltage matches the drive rating and is stable

2. Verify voltage readings in the drive

• Access the MON (Monitoring) menu
• Check ULn (Mains Voltage) to see what the drive detects
• Compare it with your actual measured voltage

3. Measure DC bus voltage

• Check voltage across PA+ and PC- (if available)
• Validate using this formula:

DC Bus Voltage ÷ 1.414 ≈ AC Mains Voltage

Example:

For a 230 V drive:
DC bus ≈ 324 VDC
324 ÷ 1.414 ≈ 230 V

If the issue persists:

• Inspect wiring and connections for damage or looseness
• Check for blown fuses or supply interruptions
• Contact Schneider Electric support for further assistance

If this article does not answer your question, check out our FAQ database that has answers to more commonly asked questions:

Frequently Asked Questions - Schneider Electric (se.com)

If this FAQ did not solve your issue, you can call us at 1-888-778-2733 Option 2 and then 4 or e-mail us atdrive.products.support@se.comto create a case with our Technical Support Team.

If you are not located in North America, please contact your local Customer Care Center for assistance:

Support | Schneider Electric Global (se.com)