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  1. A

    Fuel Nozzle Carbonization (Borescope)

    Hello to all. Introduction: The unit is Dual-Fuel 7FA turbine, DLN2.6. Primary Fuel is Natural Gas.The liquid fuel system have 3-way valve and re-circulation system. The unit runs on liquid for testing each outage period. We mainly suffer from two issues related to 3-way valve. The first...
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    Moog Servo Valve Operation

    Dear CSA, first you have my highest regards for your time and your will to help others. Actually I wasn't meaning that when the spool is in middle position, oil will be dumped into tank. what I mean there will be small flow through the nozzle (the nozzle near the flapper in the servo...
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    Moog Servo Valve Operation

    CSA, Thank you for your time. The following picture might help. https://drive.google.com/file/d/0B9R-rponHkn5TktuUWxSeUFSc28/view?usp=sharing The Pressure Compensator is usually set @ 1800 PSI. The Hydraulic Pressure Regulator is set @ 1625 PSI In case of Hydraulic Pressure...
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    Moog Servo Valve Operation

    As expected from CSA. Thank you I have one thing I fail to understand regarding this valve. First, it seems that this valve is an open center meaning it allows oil to go back into tank when there is no current applied to the coils. As you see in the link down, the pressure of system while...
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    High Spread While Burning Liquid Fuel

    Oh my bad! I forgot that the cracking pressure of the 3-Way Valve is around 120 Psig. So the pressure at the selector could be (120 + 15) Psig. So I think checking the selectors at fire mode worth the trial. >About the Firing mode on Liquid Fuel, yes it can run on Fire >Mode with liquid. But...
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    High Spread While Burning Liquid Fuel

    Dear Jolek >Do you experience check valves stuck when not running on >liquid fuel for some time and how do you deal with it? > >Do you also experience MOOG valves become ungovernable for >the same reason? Although some plants with 7FA Turbine have the conventional liquid fuel system...
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    High Spread While Burning Liquid Fuel

    CSA, Thank you for giving a background about the swirl angle (my experience is only one year, and I am really happy to learns from experts like you), and yes as you said. The swirl angle is not really accurate. The GE engineer told me that when he suspects a particular Can, he adds one Can...
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    High Spread While Burning Liquid Fuel

    To update you on this case. It seems there is a GE internal tool to help you determine which Can. In the tool you put the MW and the cold thermocouple and guide you which Can should be inspected. As you change the MW value, the positions of the thermocouples change. Furthermore, the I&C team...
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    High Spread While Burning Liquid Fuel

    Greetings to all. I will try to provide as much details here, so we can learn from each other. The unit I speak about is 7 FA turbine, dual fuel with DLN2. The unit has 14 Cans and 27 thermocouples to monitor the exhaust temperature. The igniters are on Cans 2 and 3. The flame detectors...
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    Vacuum at Bearing Housing

    Hi Venkatesh, We had the same issue once. The machine experienced vibration @ turbine bearing 2. there was coke formation on both the oil deflector and the air seal ring. One of the reasons that contributes to this issue is insufficient vacuum at the lube oil tank. maybe you have a checked...
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    Turbine Bearing Vibration and Oil Leak

    Greetings. We had vibration on bearing 2. The mist eliminator filter was choked so there was no sufficient vacuum for a period of time before the vibration happened. The clean side of the Air inlet filters was dirty (but not that much), also bore scope showed that the turbine buckets are...
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    Generator Humming Sound

    Hello. To update you on the this topic. GE recommended (as a first step) to inspect the belly band + the key bars. I believe the key bars hold the lamination in place while the belly band support the key bars. We have pulled the coolers (HXs) from their place and entered the generator...
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    3-Way Purge Valve Coking in the Purge Air Port

    Thank you CSA I don't see why loose fitting would allow liquid to the purge line. liquid goes to the purge line through the 3-way valve (possibly through the seals). Actually OEM is assisting us. OEM emphasizes that at each outage all the 3-way valves have to undergo 4 tests in the...
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    3-Way Purge Valve Coking in the Purge Air Port

    Greetings, We had some 3-way purge valves passing liquid to the can while on gas operation. We have opened one of them and there was small coking in the purge air line port. So there are two problems liquid passing to can + liquid present in the purge port. I don't know why, but one of the GE...
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    Compressor Thrust

    Dear CSA, I understood the compressor section (action & reaction). But about what happens in the turbine section still not clear, can you explain in another way. Thank you
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    Liquid Fuel Filter Thermal Relief Valve

    The unit runs mainly on natural gas, and it is 7FA turbine.
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    Liquid Fuel Filter Thermal Relief Valve

    Greetings to all, We have a liquid fuel system with re circulation and 3-way purge valve. the liquid fuel filters (we have 2 for each unit) have thermal relief valve that dumps the liquid into the false start drain (FSD) tank. These valve are to be set 105 psig, once pressure reaches that...
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    3-Way Purge Valve Passing Liquid to Liquid Fuel Nozzle

    nldgseeker , Thank you for taking the time to think and provide an answer. I haven't heard about this method actually. It might work if the problem is in the three way valve spring. But I don't know maybe the reason is other than the spring, maybe it is the seal shown in the picture, could...
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    3 Way Valve Drain Port "Vent"

    muz_sindhu, thank you for your reply. it's a 3-way valve instead of the conventional check valve. I think CSA explanation is logical, please take some time to read it. Thank you again
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    3 Way Valve Drain Port "Vent"

    Dear CSA, thank you for your explanation. Sounds logical. Any oil that leaks from the flow stream into the valve body will be drained to the false start drain instead of leaking into the turbine compartment. Thank you again
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