We have an issue in sinomics g120(0.37kW) drive. We switched off the panel Mains supply  for 10 minutes to modify some other circuit in the control panel after switching on  one of the drive  went error mode (error showing in power rack). all other drives normalized after the power up except the faulty drive.

   what is the cause to failure of the drive? why power fluctuation causes the drive failure?

we had lost 2 more drives before while our mains power fluctuated  those are also sinomics(higher capacity)

I think you may want to add a few more details like error codes, what were you doing, voltage levels, etc.

What we have here now is "My drive broke.  Why?"

Sorry i did not note down all  the error codes.which i remember is F01601(system startup error)

We switched off the panel  to add a frequency drive to one of the DOL starter inside the cabinet, after our connection is done we switched on the mains power, all other drives normalized by themself but the faulty drive was not got reset.