Hi guys I have a big problem with one ship to shore crane! I will try to describe it and hope for some help because I run out of ideas

We have 16 motors on gantry travel and 2 FC masterdrive cbp working in master/slave with possibility to operate with only one. Every FC has 8 motors connected diagonally. For a month ago motors connected to FC number2 (which in normal mode works like slave) started braking (motor frame cracking). We first thoght it was a problem with gear and checked it, drained oil to inspect but nothing suspecious , then installed new reaction bars to limit gears moving during sturt up but  nothing helped. We checked brakes but without sucsess, then we changeg encoders and meassured pulses but the problem still there.

This problem happens during low speed like 10% and when you speed up it starts going smoothly up to 100% speed but if you then slowdown and without waiting the speed to fall to 0 % want to speed up againg motors on FC2 starts jumping like crazy. 

I opened inspection wholes to see motor shaft and noticed that on the motors which are connected to FC1 rotetion during startup goes very smoothly but on motors connected to FC2 rotation is not smooth and reminds during startup phase  step motor behaviar which cause gear to jump.

Guys maybe you have ideas what it can be. Maybe there is a possibility to operate both drives in encoder less mode just to test.

Please help!!!!

Can I put  P130 to "without encoder" on both FC just for test?