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How do I troubleshoot an ATV71 with a NLP fault?

Published date: 05 August 2019

Issue:
ATV71 with a NLP: The input voltages are correct at LI. L2 and L3 and the DC bus measured correct.

Product Line:
ATV61/71

Environment:
NLP on ATV61/71 drives

Cause:
Wiring error

Resolution:
It's possible that the drive is wired incorrectly.  Line voltage should be wired to L1, L2 and L3 and outputs wired to T1, T2 and T3. The drive has protection to prevention damage to the drive if wired incorrectly, but will display NLP.Another possibility: The drive is showing nLP (no line power), but a meter check between the PA+ and PC- terminals show good DC bus voltage. The Mains Voltage in the monitoring menu shows  "no measure". In most cases this indicates a problem with either the power board, the control board, or the cable connection between them. The DC bus voltage is measured on the power board.  It is then reported through the ribbon cable to the control board. Suggestions:1. Remove the control board2. Inspect the control board, power board and the ribbon cable for signs of heat/damage3. Make sure all connections to the power board are tight.4. Reinstall the control board5. Power up and check to see if the problem is resolved.6. Check the application, motor control and product version in the Identification menu. Motor control and Product version is read from the power board  If the problem remains, try swapping control boards with a known good drive. (make sure the control boards are compatible with the drive first) If the problem stays with the drive, then it is likely a power board problem. 
 

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