What would cause a flashing C on the screen on an ATV21 / ATV212 drive?


14 July 2022

ATV21 / ATV212 drive has a flashing C on the screen

Product Line:
Altivar 21, Altivar 212.

All models, All Serial numbers.

Motor current in excess of the value set in F601.  Note:  If F701 is set to 1, then F601 setting is in Amperes.  If parameter F701 is set to 0 then F601 setting is in percentage of the drive rated output current as listed on the drive nameplate.  Factory default for F701 is 1, to indicate Amperes.

Ensure that F701 [Unit value selection (either % or Amps / Volts)] is set to desired setting, and:

F601 is set properly for the motor being used:
F601 is typically set to a level at 1.2 x motor nameplate FLA for variable torque loads, such as centrifugal pumps and fans.  If the VFD is applied to a constant torque load, set F601 = 1.5 x FLA

If these settings are correct, and current limit is still being reached, adjust the acceleration time (ACC) to a higher value. 

If Current limit is still being reached, investigate the incoming voltage to the drive:
Measure this with the motor stopped, then measure it again when a run command is given.  
If the incoming voltage is dropping significantly when the run command is given, then the motor will naturally pull more current.
Investigate the power quality coming in to the drive and correct as needed.
If the incoming voltage is not dropping significantly,  investigate the mechanical properties of the installation.
Check for bad bearings or blockage or input dampers / valves that are not fully open. 
If the drive is programmed to match the motor name plate information correctly, the motor is sized properly for the load, and there are no problems with the incoming power quality, then this is an indication that your motor has to work harder than it should for this application.  Check for any mechanical reasons that would cause your motor to worker harder than expected.