Steam Turbine is Hunting

SEE THE MANUAL OF YOUR TURBINE,,,,,IF 1750RPM IS CRITICAL SPEED OF YOUR TURBINE THEN ITS OK. BECAUSE IN ALL TURBINES THERE IS A CRITICAL SPEED AND VIBRATION IS HIGH AT SUCH SPEED. ONCE YOUR TURBINE PASSED THROUGH CRITICAL SPEED ITS VIBRATION REDUCE TO NORMAL VALUE. SO WHAT YOU HAVE TO DO IS THAT 'NEVER STAY AT CRITICAL SPEED, JUST PASS THROUGH IT' IJAZ AHMAD

thanks Yesyen, your comment is highly appreciated

Dear Yesyen,

We used to decouple the Turbine and it was run to operating speed, as result the respond of turbine was perfect no hunting was occurred! that means only with load, hunting will occurred! What does that mean?

Now Governor will be flashed with light oil then will be fill with new oil..if you have any suggestion let me know please..

apprecite every body feedback..

Droop adjustment will reduce the hunting. You can adjust the droop on load, but taking enough care and precautions. One important precaution, I suggested, was to conduct 'over speed trip test' (in decoupled condition).

Even if it is a diesel engine or the steam turbine, the governor control module is doing the job of keeping the engine /turbine speed constant by varying the fuel/steem supply under variable load conditios. In this case the turbine RPM is hunting due to distrubbed setting on the gain control and stebility control pots which are required to be set till the hunting stops. The gain and stebility controls are the integral parts of Governor control modules.Also the body of governor control module to be earthed for its safe and efficient function.

CVS Murthy

Dear,

The above mentioned problem I have faced recently in one of our turbine.When sensitivity of governor is high and governor valve travel required is very low to meet out your load,governor try to respond quickly to control to your set speed and it will create hunting.To ,solve this problem try to increase governor droop setting step by step which will decrease sensitivity slightly but hunting will be reduced.This is my experience and it can be adjusted at site or test stand.Procedure given in TG governor maintenance catalogue.Any how you have to get permission from your higher official to do adjustment.This is my suggestion only.

We have seen turbines and gas and diesel engines hunt when there has been some binding of moving components in the governor mechanism. One case was a bad bearing on a tractor and another was galling of components on a steam turbine. If everything moves smoothly look elsewhere.

Dear Mr.Fahad,

Did you try to increase the SLUGGISHNESS OF THE GOVERNOR, slightly.

If not please try and you may succeed and come out of your problem.

Thanks,

DHAYANANDHAN.S,

CR4 MEMBER, INDIA.

Dear,

Have the issue got resolved, because i am also facing the same issue. Please confirm what was your action plan to rectify the hunting.

Thanks in advance...