please i can not see picture can you uploaded to other website to see ?

 

Dear Sir,
I am not able to open the URL mentioned in your following mail communication (http://s29.photobucket.com/albums/c267/BigTom209/?action=view¤t =2-18-201011-30-23PM.flv).

It asks for login password. Please inform the procedure to open the link. This video seems to be informative on the Frame VIB gas turbines ratchet system.

Regards,
Sukhdev Singh

 

Here is another case study which might be helpful to some readers in trouble shooting ratcheting issue.

We have GE Mark V Frame 6 gas turbine usually run with gaseous fuel at base load for >99.5% time.Recently we conducted MI after which we wanted to put rotor on ratchet cycle but it did not worked.Ratchet mechanism have a self sequencer. Hydraulic torque converter is connected with starting menas Diesel Engine. Before MI ratchet system was working perfectly OK as observed during cool down cycle after machine was stopped. Problem observed was that after giving cool down ON command from mark V, DC Ratchet motor 33 HR was starting & ratchet side jaw shaft also started rotating but jaw clutch was not getting engaged (not moving in forward direction for engagement). Initially we doubted 20CS but our control guys said it is OK since power supply was OK at solenoid coils. We checked operation in all position of VM2 valve but result was same. We opened supply side tube of cylinder and oil was seen but qty was very less without pressure and gave us doubt that oil flow is not reaching to cylinders. We have Pressure gauge in 33 HR discharge which was showing pressure 55 kg/cm2 and 35 kg/cm2. As a doubt again 20 CS solenoid was checked and it was found that one power supply cable is grounded, replacing which problem was resolved. Now ratchet system is working alright.

Conclusion: If jaw clutch is not engaged or not moving in forward direction for engagement, check 20CS for proper function as oil may not be reaching to cylinders at all.

Other Possible reasons brainstormed: Chocking of cylinder supply and return tubes as we have replaced 25% lube oil in tank during MI, choking of filters in 33 HR supply line, malfunction of VM2 valve, Malfunction of cylinders.

Possible Actions to be taken: Ensure lube oil is clean. Start centrifuge after fresh oil charging. Check oil filters.

 

Here is another case study which might be helpful to some readers in trouble shooting ratcheting issue.

We have GE Mark V Frame 6 gas turbine usually run with gaseous fuel at base load for >99.5% time.Recently we conducted MI after which we wanted to put rotor on ratchet cycle but it did not worked.Ratchet mechanism have a self sequencer. Hydraulic torque converter is connected with starting menas Diesel Engine. Before MI ratchet system was working perfectly OK as observed during cool down cycle after machine was stopped. Problem observed was that after giving cool down ON command from mark V, DC Ratchet motor 33 HR was starting & ratchet side jaw shaft also started rotating but jaw clutch was not getting engaged (not moving in forward direction for engagement). Initially we doubted 20CS but our control guys said it is OK since power supply was OK at solenoid coils. We checked operation in all position of VM2 valve but result was same. We opened supply side tube of cylinder and oil was seen but qty was very less without pressure and gave us doubt that oil flow is not reaching to cylinders. We have Pressure gauge in 33 HR discharge which was showing pressure 55 kg/cm2 and 35 kg/cm2. As a doubt again 20 CS solenoid was checked and it was found that one power supply cable is grounded, replacing which problem was resolved. Now ratchet system is working alright.

Conclusion: If jaw clutch is not engaged or not moving in forward direction for engagement, check 20CS for proper function as oil may not be reaching to cylinders at all.

Other Possible reasons brainstormed: Chocking of cylinder supply and return tubes as we have replaced 25% lube oil in tank during MI, choking of filters in 33 HR supply line, malfunction of VM2 valve, Malfunction of cylinders.

Possible Actions to be taken: Ensure lube oil is clean. Start centrifuge after fresh oil charging. Check oil filters.

Can you reread your post ?

Looks like you mentioned, 33HR as "DC RATCHET PUMP MOTOR" instead of 88HR.

Just FYI

 

Just about any time one finds a grounded solenoid coil wire there WILL BE a 125 VDC Battery Ground alarm to that effect. Was there such an alarm active, and did the alarm clear once the ground was resolved? Or is the alarm still present (meaning there are other grounds on that leg of the battery)?

Enquiring minds want (and deserve) to know!!!

 

Hi everyone

I really thank you for sharing that with us ( I'm reading that 10 years later), I see that the problem is mechanical with the free wheel because the clutch was moving backward in the retraction stroke and it should not be.
But I noticed that the cycle (as described in the first post) was starting with the retraction stroke then the forward because the jaw clutch was turning backward to unlock the jaw first then it turns forwad to move the shaft and then it turns backward again for a seconde to unlock the jaw wich is the opposite of a normal cycle (forward ->backward -> forward for 2 secondes)
I think that the cycle is inversed and maybe the cause is the inversion of the 33HR (NO/NC) or the input configuration on the control system.
What do you think about that ?

 

I was going to reply right away but was waiting to make sure my solution was the correct one. I spoke again in great detail with the guys from Young & Franklin about that sequencer and figured it's got to be functioning like it should based on all the videos I took and looking at the 33HR tag switching etc... it is functioning. We know the 33HR and 33CS switches are good and setup properly, the control system was working... it's got to be inside that hydraulic ratchet. So I went digging in the library and found the binders for the station and the service manual for the Twin Disc torque converter (with ratchet installed on the side)

Basically how it works either the diesel or the hydraulics has the ability to turn the jaws, the hydraulic is designed I guess mostly for cooldown period as well as startup to break the static friction for when the diesel starts, our system has been changed so we ratchet all the time every 3 minutes except for startup where we set it to continuously ratchet until the diesel takes over and spins the rotor up to speed.

Anyway now I had the part number for the company and started calling all the service departments listed on the Twin Disc site, eventually after many confused phone calls I found a old service guy with 40+ years exp and who's worked on these before. I mentioned our symptoms and sure enough he said it sounds like the inner cam is worn out and now allowing it to freewheel which is why in the videos you can see the jaws move backwards which they should never do.

So, a brief run down of how that works if you look at the hydraulic schematic there is the F and R lines that goto the right piston as well as the Fs and Rs. The sequencer through the reversing valve which is controlled by the shuttle valve can put pressue either way, and at startup idealy it pressurizes the Forward line driving the piston down, at the end of the travel I'm not sure exactly which but the piston moves out of the way and signals either the FS or RS line indicating the stroke is finished, this switches the shuttle valve in the sequencer, which switches the reversing valve, and therefore changes the stroke to push the piston in the opposite direction.

This piston in the center is geared and as it moves up and down there is a center circular one way cam that acts on the torqe converter, this cam as it rotates there is an inner cage that holds 22 or so rollers, as the piston rotates it rotates this cage which moves the rollers up the jawls and wedges them into place locking the cam and turning the torque converter. Once the forward stroke is finished and the reverse starts the cage is spring loaded so the pressure moves off the rollers and they roll back and basically freewheel for the reverse stroke so the shaft doesn't turn.

Clear as mud?

Anyway I spoke with a guy who had a Frame5 unit and problems with his gear and he sent a bunch of really good pictures showing the guts of the system and how it all works, hopefully again these pictures will work

http://s29.photobucket.com/albums/c267/BigTom209/Frame5/

Once we tore into ours we found the problem, one of the bars on the inner cage broke free and likely got wedged behind the roller and snapped it in half. The unit was full of metal and in pretty rough shape, I also noticed 5 other bars on the cage were cracked so likely not much longer we would've had even more issues

http://s29.photobucket.com/albums/c267/BigTom209/DamagedCam/

So, luckily a service tech within 8 hours away had a rebuilt cam squirreled away in the back room and we were able to get it in and installed within a few days. Likely we'll have to take a major overhaul of that torque converter cause judging by the horizontal play in the bearings likely that torque converter needs a complete overhaul as well... another big job.

So that's where it stands, I could go into more details but I think I covered it good enough

Hi BigTom209. I have a similar problem where the baring gear is not working correctly and apears to be rotating in the wrong direction. I suspect the cage or parts within it has collapsed or is worn or damaged. Before we open it up it would be good to have a look at the photos you posted above. I cannot access them. do you know of a way that I might be able to? I see the thread was in 2010 so I'm keeping my fingers crossed.

 

Hi Bigtom209,

We are experiencing the same issue as you described in this thread.
Can you please share the pics and video to troubleshoot the ratchet issue we are facing.

Thanks