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mirak, As long as the exhaust temperature spreads are within reason, the unit can be loaded to Base Load. As for the source of liquid fuel "above" and "below" the purge air check valve, there will be liquid fuel on the downstream side of the check valve when the unit is burning liquid...

wikipedia.org has an excellent description of axial compressors; the 'Design' section's final paragraph talks about how bleed valves protect axial compressor during off-speed operation. Accelerating from zero speed to rated speed is considered off-speed operation. Compressor bleed valves...

mirak, It's rare that all ten combustor liquid fuel pressures are equal. The accepted difference is +/-10% of the average, and that's generous. Any pressure more or less than 10% of the average is considered suspect when troubleshooting high exhaust temperature spreads or combustion trouble...

Manoj, We don't know what kind of control system is used on the H-25 GT at your site. Many H-25 GTs use GE Mark* turbine control systems, and for the most part Hitachi seems to adhere to many of the proven GE control system practices and philosophies--but not always. Generally, HMIs (for...

MAHENDRA, Have you tried right-clicking on the block and then selecting 'Block Help'? Since this is a block and not a macro, there will be a Help screen that will pop up, with a description of the block, it's inputs and outputs, and its function. It can even be printed (or copied to a MS-Word...

Yes, it would be most helpful to understand the controller and the application/usage. Is the frequency input to the controller not configurable so that you could define 380 Hz as 100%? In other words, can you change the input scaling to percent and define 380 Hz as being equal to 100%? Or...

It sure sounds like there is a serious dust problem, and that can present unique challenges. I'm sure people at the site have been working on solutions for as long as the units have been in service (as well as living with the problem). Is GT1 closest to the coke yard? Does it get more coke...

The alarm is saying the turbine control system has detected that the compressor is approaching or has reached the limit of normal operation, and is limiting the fuel to prevent damage to the compressor. This can occur when the inlet air temperature is very cold; the air is more dense and the...

VKGUPTA, It seems you are assuming the output of the transmitters is 4-20 mA, and if they were then the signal should be connected to the 20mA terminal. But, many of the four-wire transmitters used by packagers of GE-design heavy duty gas turbines had 0-5 VDC outputs, and if the 96FG-2A, -2B...

MAHENDRA, No; the OEM's control philosophy and general programming practice does NOT allow operators to open the IGVs above the calculated reference. There is usually an IGV display on the HMI, and there is sometimes (not always) a couple of buttons/targets which will allow an operator to...

MAHENDRA, Each of the function blocks in Mark VI Toolbox has a type/name at the top of the box. Can you provide the function block name and describe the inputs to and outputs from the block? Generally, for most GE-design heavy duty gas turbine, bearing drain temperatures are only monitored...

Is the speed hunting occurring when walkie-talkies are keyed in the Accessory Compartment?

I would say yes--if the OEM/packager has a restriction on operating the evaporative coolers below 70 DGA then it's likely because of a risk of damage to the axial compressor--either the IGVs or the first stages of the compressor. Again, because of the increased mass flow at reduced IGV angles...

The VFD application is much better.

VKGUPTA, The problem is most likely either of these two possibilities: 1) The wrong wire was used to connect the three P2 pressure transmitters to the Mark VIe. It should be twisted, shielded pair wire with a drain wire. I have seen many sites that tried to use single conductor wires, or...

abdi, I've worked on a LOT of dual fuel machines and I can never remember every having to perform maintenance on VA19-1--ever. I did hear of one VA19-1 actuator diaphragm that ruptured, but that was because of a failure of the pressure regulator, and I would consider that a repair not...

Kind of an important detail, that bit about being an island power system.... Is the unit operated in Droop speed control or Isochronous speed control? If the unit is operated in Droop speed control where does the speed/load reference signal come from? Does it come from some kind of PMS (Power...

Rom, While it's very difficult to predict with great certainty how any instrument or device will fail (including the wiring to/from the device), the predominant failure mode for IGVs is to fail in the open or low condition. That's why the Speedtronic does a high-select of the two LVDT...

Sadiya, Yes; the manual jog feature relies on the turbine control system. So, if the turbine control system is not working, then the manual jog feature isn't going to work, either. This topic--an inability to maintain cooldown (be it hydraulic ratchet, or turning gear, or slowroll)--has...

VKGUPTA, You have a GE-design Frame <b>5</b> heavy duty gas turbine with a Mark VIe control system. Is the unit a generator drive? Is it connected to a large grid, or does it supply a small load independently of a large grid? Because, when a generator is connected to--synchronized...