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Dave, Here's how I would explain your scenario, from a slightly different perspective. When a synchronous generator's output (watts) is constant and its terminal voltage is exactly equal to the grid voltage, the VAr meter and the VAr flow is zero, and the power factor meter reads 1.0 (unity)...

Hello, Dave, (Wow--that was a deja vu moment! Like something out of '2001: A Space Odyssey.') I agree with most of your understanding except: > Leading VArs and Lagging VArs of the same magnitude will “cancel” each other out. Lagging VArs <b>"feed"</b> a lagging load--<b>from a...

Ahmad, One other very common cause of instability and hunting is liquid fuel supply pressure. Many times, there is a pressure regulator used to set and maintain the liquid fuel supply pressure to the Liquid Fuel Stop Valve on the turbine accessory base. This pressure should be approximately...

Ahmad, I don't think you're going to find much experience here with Ovation control systems on GE-design heavy gas turbines. There are only a handful worldwide, though Emerson would like to greatly increase that number. We don't know what version of Frame 7 you have: 7B, 7E, 7EA, or one of...

Searching, Yes. Heat causes expansion, and expansion of a bearing housing can cause alignment changes, which can lead to vibration. In the future when posting to control.com, please provide as much information as you can about the turbine and auxiliary equipment involved as you can. While...

Suman, The only question we can possibly answer based on the information provided is the one about how much electricity can be generated from a steam turbine in combined cycle operation. The generally accepted guideline is that a steam turbine can be used to generate approximately 0.5 MW...

sriram sandeep, It would be done exactly as you describe. Unload the machine (manually or automatically) to some load just about zero MW, then manually open the generator breaker. There is usually a switch on the Generator Protection Panel or switchgear panel for the Generator Breaker to do...

sriram sandeep, Some sites synchronize the gas turbine generator across a breaker that is on the high-voltage side of the main step-up transformer; in fact, many F-class turbines do this. So, it would seem that whomever designed the plant where you work must have had a specific...

Eskay, Funny you should post this question today, as I have spent several hours by telephone and email helping a site with this very same problem today. GE, in their usual (undocumented) manner, wrote some versions of Toolbox to warn the user of a Minor Difference when a new Watch Window...

gsh, Almost every instrument (with the exception of RTDs and thermocouples) has a "zero" setting, or needs to put in a linear range to operate correctly. That's what the -10 VDC does--puts the proximity probe and associated proximitor in it's linear range of output. (Some people believe the...

Ashutosh, You also have a P&ID of the lube oil system, which you can use to understand how the drain and vent are attached to the lube oil filter "canister"/vessel. It would also be advisable to review the L.O. & Accessory compartment drawings to be sure you are operating the correct valves...

gsh, There are vibrations sensors, and there are vibrations sensors. Specifically, there are velocity sensors (also referred to as seismic pick-ups). There are accelerometers. There are proximity probes. This is a technical forum. <b>What kind of "vibration sensor" are you referring to...

Koukos, There is a saying in the Western world: "Curiosity killed the cat." In other words, a curious cat that is not cautious can experience loss of life. The loading (and unloading) rates of a Speedtronic are adjustable--within limits. By design, the "manual" loading (and unloading)...

Controman makes an excellent point! Be sure to check the lift or "jacking" oil pump flow, if your machine uses it. And the best way to do this is with the B-N proximity probes if they're installed. This kind of information--about your machine and its configuration is very important to...

I probably need to add to the explanation that in an AC machine (motor or generator) the magnetic poles created when current is flowing in the stator appear to "rotate", and they rotate at a speed that is proportional to frequency and the design of the machine (which includes the number of poles...

<b>When did this problem start?</b> is always the first question that should be asked whenever something like occurs on a machine that has been running fine. After a maintenance outage? Were the generator bearings/seal oil rings removed and/or replaced during the outage? Was the generator oil...

GenSet_Expert, The whole purpose of matching speed and phase angle is to make sure that when the generator breaker is closed that the rotor magnetic poles are properly aligned with stator magnetic poles so that when the breaker is closed rotor North is near stator South and rotor South is...

Torque converters do wear out and do require refurbishment. If the site uses the cranking motor for forced cooldown and/or off-line water washing this, too, can accelerate the wear in the torque converter. Also, it's common for the Torque Adjustor Drive mechanism limit switches to require...

Magnetism.

Yes; "spares" have been known to be bad "out of the box" also (unfortunately). Thanks for the feedback! "Feedback is the most important contribution!"(c) here at control.com!