During start up of Fr.6 turbine (Mark VI control system), at cool-down on, ratcheting worked for two cycles, then the timer continued to run without stop. On checking at Mark VI side, found that the L33HRF signal did not actuate to reset the cycle. Hence the solenoid L20CS1X and the ratchet motor was continuously energized and got heated up. Ratcheting mechanism was then isolated at MCC side.
Limit switch actuation was checked from field and found to be ok.
Ratchet line 40micron filter was cleaned and this improved the performance. Still the ratcheting time is well above the original 30 seconds. Now it varies from 1 minute to 2.5 minutes. L33HRF limit switch actuation time has got delayed.

Could the problem be due to
1) Filter chocking
2) Ratchet motor pressure not developing
3) Self sequencing system trouble

Also will continuous powering up of L20CS1X damage the solenoid. Does the limit switch need to be changed.

 

Anish,

We had the similar problem in the past.

please check the below

1. VM2 three way valve for passing.
2. Passing in the small cylinder for clutch engage / disengage.

the above both we observed in two different machines.

let's know your feedback.

Take care
G.Rajesh

 

Dear Rajesh,

VM2! did you mean 4 way manual valve - there is no leak.
Also no leak in ratchet cylinder.
Regards,
Anish

 

Normally extended ratchet cycle times are caused by not making the forward stroke and therefore never cycling 33HR so the system never gets reset and keeps trying to run to get 33HR to cycle (Forward & reverse stroke completed).

Usually this is an operating pressure problem (Low). I would replace FH-2 if you can, this has been a common problem. Check if there is a filter on the pump Inlet side, some machines have, if it gets clogged it has the same effect as FH-2 getting clogged. The fact that you cleaned FH-2 and got a better response pretty well points to low pressure.

Make sure VR-5 is set correctly and not relieving (I think 90 Bar)this can cause low pressure but you should be able to hear it relieving, it is pretty noisy if it is passing.

Good Luck and please report back.

 

Fortunate/Unfortunate, i got the opportunity for which i was waiting since posting this query.

Ratchet pump inlet and outlet filters were changed with new one. Tested ratchet cycle. Now the ratchet cycle is well within 15 seconds. And the timing is steady.

The problem was with the micron filters.

Thanks & Regards
Anish

 

Good to know your problem has solved.

Take care
G.Rajesh

 

> Fortunate/Unfortunate, i got the opportunity for which i was waiting since posting this query.

Thanks for posting an update. It helps others when posters explain how their problem was resolved.

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