After a sudden shut down of our GE frame 5 gas turbine, the unit refuse to ratchet. and after 48hrs of this event, the starting jaw clutch will not turn the turbine shaft. investigations have been carried out on the torque converter to see if there is any damage to the pistons but no damage was noticed. please i would appreciate help on this matter as i am new in the field.

 

We don't know what kind of control system you have, nor enough information about the ratchet.

Does the unit have a ratchet self-sequencer?

Does the jaw clutch close?

Have you tried installing a temporary gauge in the forward stroke piping to see if pressure is being established?

What is the position of VM-2?

If the unit has a self-sequencer, what is the state of logic signal L33HRF? (It should be a logic "1" at the end of the forward stroke, and remain a logic "1" during the retraction stroke, and then change back to a logic "0" as it start to go into a forward stroke again.)

What process alarms are being annunciated when the unit is trying to ratchet?

Is the DC ratchet pump motor running?

When was the last time the filters in the ratchet system were replaced?