What would cause a pump to oscillate (or surge) up and down when ramping up to speed on the ATS48 soft starter?

Issue:
A pump is oscillating (or surging) up and down when ramping up to speed on the ATS48 soft starter?

Product line:
Altistart ATS48

Environment:
All models, all serial numbers

Cause:
Excessive motor slip

Resolution:
In the drC menu, reduce LSC.  Generally, LSC = 30 will suffice.
LSC = Stator Loss Compensation
Oscillations are most common when controlling a motor with excessive slip.

Another option is to turn off the torque control.  In the drC menu, set CLP = OFF.

Refer to the ATS48 Programming manual S1A37491

Released for:Schneider Electric USA