Trouble in Hydraulic Ratchetting mechanism of Frame V GTG


Thread Starter

Uday Rajhansa

In one of our 17.225 MW Alsthom Make Gas Turbine Generator (GTG), we are facing a slight problem with regard to the Hydraulic Ratchet Mechanism. The Jaw clutch is coming out/disengaging the clutch at the end of each Cycle. This is causing the limit switch 33 CSE1 to drop and thus restarting the cycle all over again.

We have checked the settings of all the check valves and relief valve and it is as prescribed. The self sequencer is also replaced but the problem persists. Pls advise.

Uday Rajhansa
please i have some question in this topic. we face problem in GTG same unit hydraulic ratchet failure. and we have another problem hydraulic ratchet overload

Please check both jaw clutch cylinders, replace them,may be they are worn out and internally leaking out oil to the drain port also check the hydraulic pressure connection to the cylinders which comes out from the clutch manual engage disengage valve. Check the condition of the jaws, align them properly, are their edges not worn out.Check properly all the tubing is properly connected as per the PID drawings.

Please check the inline filter to the Hydraulic Motor, also check the inline filter to the ratchet mechanism -FH-5, if they r found ok then check the cause of the turbine rotor not moving freely, check the solenoid 20CS for proper functioning

Uday Rajhansa,

If u still haven't find a solution to your problem with ratchet system, pls check the play / free movement of the driving clutch flange. It is most likely that the key / key slot or the teething inside the coupling sleeve is damaged, which causing the coupling flange to be able to move reverse one or two degrees at the end of each cycle, resulting disengagement of the clutch.