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Mark Vie Controls
T40 and T10 controller in Markvie

While am analysing the trend data of a PGT 25+ Gas turbine I found that there is T40 and T10 controller? Can you explain about that controller?

Few seconds before the Trip activation the speed signal on T10 controller decreases rapidly around 3000rpm within 43sec. How it can happen please give an explanation?

The PGT 25+ is an aircraft derivative engine, and as such, the control schemes are based on those used for aircraft derivative engines, using the signals associated with various sensors.

I think you need to find the operations manuals provided with the engine and have a look through the system descriptions section to understand what the various control signals and sensors are called and how they work to control and protect the engine.

I, personally, have no experience with PGT 25+ units, and very little experience with LM units (their "bigger" brethren). I seem to recall that when a sensor name/designation begins with a 'T' it stands for temperature in a particular area. My understanding of PGT 25+ engines is that they are multi-shaft units (an HP (High Pressure) shaft, and LP (Low Pressure shaft)). And, it's very likely that the exhaust temperatures of both the HP shaft (sometimes called the GG, or (Hot) Gas Generator section) and the LP shaft (the "power" or "free" turbine) are both monitored with thermocouples. (In the LM units, I believe the HP exhaust sensors are T54.?.?.? or something like that.)

Anyway, the other place to "look" is using ToolboxST to find and follow the sensor signals through the application code (or maybe they use SFCs instead of FBDs for the PGT units???). But, still, you should be able to use Finder in ToolboxST (no password required) to find and follow signals through the "logic" or "code."

I was hoping someone with experience with the PGT units would respond, but I don't think there's a lot of them (people with PGT unit experience--that read control.com, unfortunately).

Hope this helps at least a little. I may be entirely wrong about 'T' being temperature-related, but I think this should get you started in the right direction. Use the manuals provided with the unit to research systems and signal naming--I don't think that has changed very much over time, so they should be somewhat helpful.

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The PGT25+ is the GE Aviation LM2500 aero derivative engine packaged back in the day by Nuovo Pignone.

PGT is sort of their brand name for their package.

The LM2500 is a two shaft machine with the LP turbine being a free power turbine.

Nuovo Pignone was primarily a driven process compressor company that used these engines and others as their prime mover. Nuovo Pignone was acquired by GE in the early 90s and were primarily known as GE O&G (Oil and Gas) and expanded in this market to other services. Several years ago when GE merged with Baker Hughes the O&G division was included in this GE business group and are know as BHGE as of now.

The Woodward controls versions of these packages did not have anything I recognize as T40 or T10. The LM2500 GE temperature indicator numbers are T0, T2, T3, T4.8 (T48), T5.4 (T54), or T8.The engine basically from inlet to exhaust was divided into numerical "stations" from 1 to 8 ... etc.
T0 is pre filter inlet temperature.
T2 is turbine bell mouth inlet
T3 is compressor discharge temperature
T4.8 is HP turbine outlet temperature
T5.4 is PT (power turbine) inlet temperature.

You have mentioned the speed signal on the T10 controller so I am thinking it may not be a temperature control.
It may also be possible if you are a compressor drive (i.e. not a power gen) that maybe these controller names
have something to do with the anti surge.
The systems I have experience with had external driven compressor controllers and I have little experience on the compressor control side of things.

It maybe helpful to also understand what the first out trip was indicated as.

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T40 is used to control AUX system which means controller speed 40ms roughly. T10 is used to control core system (engine) which means controller speed 10ms roughly.

3000rpm dropping within 43sec, because of the trip. The fuel gas shutoff valve will shutdown immediately, so the speed dropping 3000rpm with 43sec is normal. Further more, depends on the trip type (EDS, ESN, NS, SD), The speed mapping is different.

have a nice day
YD

But speed starts to decrease before L4T signal activation. That's why I had doubt about that?

First, your description is not efficient enough. We can not understand exactly what had happen at your site.

Second, the speed drop 3000rpm is the GG speed. So after that GG speed should be around 7000rpm (full speed is 10100rpm). So depends on the configuration of your site, I guess that your GG goes idle speed (nominal idle speed is 6000-7000rpm, depends).

Why speed drop before L4T active; I guess that "step to idle" is triggered first.

The more information you post, the more detail I can give.
regards
YD

hello Mr. YD,

I have two controllers T40 and T10. Both controllers storing the value of gg speed. But before initiate the L4T signal. the speed value in T10 controller decreases rapidly around 3000 rpm within the 43 sec before L4T activation. but value on T40 controller not decreased, it decreases after the L4T activation only.

so my question is >>T10&T40 processing GG speed, but how the speed value on T10 decreases rapidly but the T40 remains same. how it can happen?<<