Issue:
Why does my drive display dCb when stopping?

Product Line:
ATV31, ATV312, ATV32, or ATV320

Environment:
All

Cause:
Why does the drive show dCb on the display?

Resolution:
dCb indicates DC Injection Braking is active in the drive.
This is a mode of stopping the load where the drive will inject DC voltage/current into one phase of the motor and is used to produce stopping torque or kill any momentum left in the load.  It does not provide holding torque at 0 speed.

There are 3 methods DC Injection that can be set up in the drive.

1. Auto DC Injection under FUN menu, AdC submenu, AdC parameter set to YES (default).  This injects the DC current after the VFD brings the output frequency down to 0Hz.
2. The Type of Stop can be set to DC Injection under the FUN- menu; Stt- submenu; Stt parameter could be set to dCI.  This injects DC current to produce stopping torque rather than ramping down the output frequency.
3. A logic input can be configured to command a stop using DC Injection if that input gets turned on.  FUN- menu, Stt- submenu, dCI set to one of the logic inputs. When that input is on, the drive will be in DC Injection.

Consult the specific drive programming manual for details.

Released for:Schneider Electric Global