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Saravana, Your statement/question is baffling. If you want to know why some machines can only be started at zero RPM and others can only be started from some higher RPM, then you need to analyze the types of starting means (if any, because you are lumping steam turbines and gas turbines...

mwadym, Your understanding is correct for a load rejection event.

Dang Khoa, You can try rotating the shaft with a frequency counter connected to the "tachometer" leads. A digital VOM with a frequency sensor should work just fine. If it will read frequency, particularly at low RPM, then it's likely many if not most frequency counters/displays will also...

Ch Amir Islam, If the turbine at your site has a turning gear coupled to the shaft via a SSS clutch <b>AND</b> the turbine exhausts into a Waste Heat Recovery Boiler (or HRSG, Heat Recovery Steam Generator) and the turbine speed is erratic shortly after the turbine is shut down but then...

Saravana, I neglected to ask what kind of GE-design gas turbines you are referring to--and what kind of Siemens gas turbines you are referring to. But, I may be able to answer your question about why some (NOT ALL) GE-design heavy duty gas turbines are not permitted to start above zero...

Ch Amir Islam, You seem to be describing the "slow-roll" turning gear mechanism in use on many GE-design Frame 9E heavy duty gas turbines, that uses Aux. L.O. Pump discharge pressure through the starting means torque converter as the energy to keep the turbine-generator shaft spinning when on...

Saravana There are lots of cooldown mechanisms in use on GE-design heavy duty gas turbines. There are turning gears (AC electric motors with gear mechanisms to keep the shaft turning slowly at several RPM while the axial compressor rotor is cooling); there are slow-roll mechanisms that use...

msalem, Something is amiss, because as you suspected the IBH control valve should NOT be opened during Base Load operation when the IGVs are at the maximum operating angle (which you indicate is 84 DGA for your machine). IBH is used to allow low-load operation while maintaining low...

Pramod, The most common problem with atomizing air pre-coolers is the incorrect adjustment of the temperature regulating valve. The temperature regulating valve is to be set to maintain approximately 135 deg C (275 deg F) upstream of the Main Atomizing Air Compressor inlet (suction). This...

syed_hassan08, Your post is unclear. Also, without time/date stamps of the alarms in the list below it's very difficult to say what initiated the problem. <b>IF</b> the alarm at the bottom of the list is the first alarm in the string of alarms, then it would seem the TCEA in Loc. 1 of the...

Mohsen, What kind of compressor are you talking about? What is the context of the conversation or documentation in which you came across this term? We don't have enough information to be able to say anything other than one doesn't want to use a turbine that is underpowered or doesn't...

sd123, Thanks for the information. I, too, have measured low resistance ("continuity") between fuse clips on TCPS cards when the fuse was not installed. Without having any elementary (as GE calls schematic drawings) for the cards I have to say there must be parallel paths which cause this...

M, Synchronous generator terminal (stator) voltage is a function of the speed of the generator rotor (field) and the strength of the magnetic field (rotor). Since, when the synchronous generator is operating at rated frequency, the speed will be constant the only way to change terminal...

The ALL parameter includes FORMAT (which effectively erases the EEPROM) and TOTD (Totalizer Data). If the Totalizer Data <b>ISN'T</b> uploaded before it is downloaded then old, or even blank Totalizer Data will be downloaded with ALL. I've been ruminating on this, and while it seems like the...

Ramakrishna, You are most welcome, sir. When operating as an island (separated from the utility) <b>EVERY</b> synchronous generator is running at the same frequency because they are <b>synchronized</b> together. That's the definition of synchronism--all generators are operating at the same...

Ramakrishna, Without some kind of PMS (Power Management System) or over-riding frequency control scheme when operating in island mode it's best to have one unit in isochronous control, which means all others would need to be in droop control. While this <b>DOES NOT</b> relieve the operators...

Ron, When you say "...DC feed..." are you referring to the two-conductor cable that feeds the DTBA, and is jumpered down to the DTBB? They come from the <PD> core; I think it's from the J12C (for <QD2>) connector/fuses in the <PD> core. I think there are LEDs on the fuses (at least one of...

Dhinesh, Every manufacturer accomplishes gas turbine emissions reduction in a slightly different manner. I am personally only familiar with GE-design heavy duty gas turbines, and so can only address them here. But, I believe, there are some similarities that you can use to further your...

Jorge, Probably the best depiction of any Mark V printed circuit card (terminal board or I/O card or otherwise) you are going to find will be in Appendix D of the Mark V Application Manual, GEH-6195. To the best of my knowledge, GE has not released the "back-sheets" (printed circuit card...

Seobong, <b>When did this problem start?</b> If this problem has just recently started, <b>What has recently changed with regard to the way the turbine is being operated?</b> (Perhaps a new Control Room operations manager has instructed the operators to do something differently than was...