Hello and thanks for your few informations helps

It is hard to explaining all things but we try make a true diagnostic for these frustrating results

A technical problem appears for powered a 3 AC motors (no having the same torque) and to make turning together and they are controlled by synchronization from changing theirs parameters .. a 2 motors can’t turn together when starting by the drive!,.. this case it use Sinamics S120 Unit control Cu320  .. it means when start running one motor from these two motor the second cannot controlled by the drive .. we are not sure if they are regulated by using only starter software?! because the all AC motors had be Autotuned as looking well by using the Starter and if no have other problems should be regulated  ..?!?!? (this case it use software Starterdrive v.4.1 .. and the version of Simatic Manager 5.6 selected by the Sinamic s120 version 2.6 ?! )