I had a sneaking suspicion about the Dahlander drive. Furthermore, if it was used wit an SEW ASD befoe, I was wondering if the speed-change did not initialize a new set of parameters in the drive first. The two sets of windings WOULD make that necessary. I am not aware if you can do that with the AB drive. So either you go back to the original SEW drive with the exact parameters they had or buy another drive and have two AB drives, one for the low speed winding and one for the high speed winding. Isolating contactors and all that jazz...a POA.
The flying restart with a single is not working since your motor parameters are different for the two windings. At initialization, when the motor performs the characterization of the circuit only one set of windings are characterized and when you switch to the high speed winding, you will have what you're experiencing where the ASD is trying to control based on the original set, so it is 'adjusting' when you switch to high speed and even with that it is questionable if it can control it correctly from that point to the end of the speed curve.
You can try to use a single winding, I would choose the high speed, and reconfigure your controls around it. The question here will be if you can develop sufficient torque on the high speed winding for the low speed start. Instead of Hi/Lo speed pushbuttons just a 'dimmer' style potentiometer to go from zero to max speed. If you choose the two speed then eliminate all contactors and have the two speed controls directly wire into the ASD inputs and have the two speeds associated in the programing with the two inputs. Since this is a crane application and safeties are involved I wonder if the SEW had a 'safety stop' input.
