GE 5001 torque converter not turning turbina shaft

We have a problem with a GE heavy duty frame 5 turbine, MKV control system.
During crank stage at 2200 rpm in starting diesel motor, turbine shaft remains stopped, We had place one manometer for read pressure in charge pump discharge, the pressure is 4,8 barg.

We replaced torque converter-hydraulic clutch assembly, but we got the same results.

Any suggest?

Thanks in advance

Does the diesel lose speed when it's trying to rotate the turbine shaft?

Does the torque converter housing get warm or hot when trying to START the unit?

It would be most helpful to see the Starting Means P&ID from the unit.

There is often a solenoid-operated valve to control flow through the torque converter; sometimes it's necessary to energize the solenoid to fill the torque converter and be able to transmit torque, and other times it's necessary to energize the solenoid to reduce the output of the torque converter--without being able to see the P&ID it's difficult to say which your unit has. BUT, there is almost always a solenoid and it's important that it be working correctly.

Second, it's almost impossible for a starting means (diesel engine in your case) to start a turbine-generator shaft spinning from zero speed without an assist from the hydraulic ratchet mechanism. That's right--when the signal is given to start the turbine, at some point the hydraulic ratchet mechanism is started. It is the "bump" from the action of the hydraulic ratchet that actually provides the force necessary to overcome the inertia of the turbine-generator shaft to start it rotating. SOOO, the hydraulic ratchet has to be working during a START in order to assist the starting means in breaking the turbine-generator shaft away from zero speed. Once the shaft is detected to be rotating, the hydraulic ratchet is immediately shut down.

So, you need to look at two things: the operation of any solenoid associated with the torque converter (usually device number 20TU-1, or something similar), and the operation of the hydraulic ratchet mechanism.

There is usually a manual hand valve which quite often gets bumped into a position that does not allow the hydraulic ratchet jaw clutch to be closed, and so the jaw clutch halves never engage each other. The starting means side of the jaw clutch rotates if the manual valve is not in the proper position--but if it's not engaged with the turbine side of the jaw clutch the turbine shaft is never going to move. Again, this manual valve is shown on the Starting Means P&ID. (I am presuming the unit has a jaw clutch--it might have a SSS clutch--but without the P&ID we can't know. If the unit has a SSS clutch, those things rarely, if ever fail; they are very robust.) To know if the jaw clutch halves are engaged, check the state of the logic signal L33CSE; it should be a logic "1" when the jaw clutch halves are engaged. You can also use the Hydraulic Ratchet Jog Pushbutton on the side of the Accessory Gear Box to test the hydraulic ratchet operation to see if it's working correctly (the jaw clutch halves are engaging and the shaft rotates approximately 45 degrees and then pauses then starts rotating again--as long as the pushbutton is depressed).

The P&IDs for GE-design heavy duty gas turbines are EXTREMLY important and necessary when troubleshooting problems. Get familiar with the P&IDs--they have lots of important and useful information and can prove critical when trying to troubleshoot problems.

Please write back to let us know how you resolve the problem! If you need further assistance, please scan the Starting Means P&ID and attach it to this thread.
I forgot to ask (because I usually regret asking...!): What Process Alarms are present or annunciated during the START attempt?

Please list all alarms in chronological order--even the ones you don't think are relevant.
Thanks, for your further responde

There isn't solenoid valve (20TU-1) installed. Charge pump discharges direct to torque converter assembly, however we suspect failure of the hydraulic ratchet mechanism, in fact jaws are engagged, 88HR-1 Is starting but the shaft not turns.

To be continúes...

We did correct some issues related hydraulic ratchet mechanism like lost of calibración in the travel of jaws hydraulic cylinder and oil leakages, in adition the filters involved were cleaned.

We had make cranking w/o problems.

Thanks a lot for your support

Best regards

Thanks VERY MUCH for the feedback!!!

We are VERY HAPPY to hear you were successful. Sometimes the adjustment of 33CS needs to be made, and leaks may make it more difficult to reach the end of stroke/engagement.

The important take-away here is: The torque converter and starting means by themselves are not capable of breaking the turbine-generator shafts away from zero speed without the assist from the hydraulic ratchet. I have seen it happen on units with "old" turbine-generator shaft bearings (worn) and new/refurbished starting means (diesel in your case) and new/refurbished torque converter, but if the turbine-generator shaft bearings are in specification or recently replaced it's difficult to get the shaft to move without that "bump" from the hydraulic ratchet.