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What does NST mean on the Schneider Electric Drives?

What does NST mean on the Schneider Electric Drives?

Product Line:
All Altivar drives


NST is not a fault but rather a status indicating the drive is in a freewheel stop condition.

Causes and fixes :
  1. The VFD is in 2 wire control (TCC = 2C). If the drive was powered up with an active run command, cycle the run command or set TCT to LEL. IO menu, 2 wire type = level
  2. The VFD has an input assigned to Freewheel stop, NST?   The input needs to be active.
  3. The VFD is in 3 wire control (TCC =3C). LI1 must be active before the NST will clear.
  4. The VFD is being controlled by serial communication.  The drive will display NST until the correct value has been written to the command word.
  5. A loss of a 4-20mA signal is programmed to freewheel stop.  When the input lost, staus goes to NST. Verify the 4-20 mA signal.
  6. The VFD run command is not via a keypad.  The STOP button on the integral or remote keypad functions as an E-STOP.  If the keypad STOP button is pressed, the drive will go to NST. Power cycle the drive to clear the NST..
  7.  For the ATV61/71 VFD only:   If the drive is running and the voltage applied to the PWR input terminal drops below +19Vdc the drive will stop and display NST.  You will need to make sure you close the +24 VDC to PWR input and cycle off and on the run command again.
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