Hi my friends:

We have six Gas Turbines MS5002D. One of them had the problem of LP Shaft rotor locked during start up (last week). The operation group tried for 3 times start up and in the third start the problem resolved and they could load the turbine. after 4 days the stopped the machine. Today the tried to start it again but again ( LP Shaft rotor locked ). Would you please tell me what is the reason?

 

You really haven't given us much to go on. There is nothing in the standard GE 2-shaft turbine control that can "lock" the LP rotor, so I would tend to say you have a mechanical problem, most likely in the load equipment, whatever that is.

Where there any alarms while the unit was last running? E.g., vibration alarms, bearing temperature alarms.

We really need more information to be able to analyze this, but I doubt that it is a control problem. It is pretty hard to "lock" the LP rotor. GE does it during factory test where no load equipment is available, but that involves bolting the flange on the LP shaft to a fixed plate - not something that's going to happen on its own during a shutdown!