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Hisam, there is no need to slam a valve shut if the machine or process the valve interrupts is a consequence of a shut down, but none of its monitored parameters is the root cause. When I provided ESDs (then called Emergency ShutDown systems) two trip-valves were often provided... one used...

James... thanks for making my point, which was that engineers often overlook a very common problem! The problem I alluded to was that the insulation rating of all wiring must equal or exceed the maximum circuit voltage within the cable. By now, some of you have already applied the Italian...

Bill... I never said power and communicatons circuits were disallowed in the same cable! Certainly, your EMI abatement suggestion, as well as short-circuit consequences are covered by the "GEP" umbrella. I just pointed out that there are legal restrictions to consider... espscially in the...

Bill... the corrective action you recommend may be void if the installation violates NEC requirements. A common problem often overlooked by engineers! The referenced thread in my previous post will tell you why? Regards, Phil

Roy... although you have had success, it doesn't mean every installation will be successful: See thread "1026211569" covering interference between 24Vdc circuits and data-communication circuits. Regards, Phil Corso (cepsicon [at] aol.com)

Many, many words, but no mention of the role steam and drum-size plays on level control success! I remember the gOLDen days when the "Integral" portion of PID control, was simply the addition of a capacitor or two. Search the Control List Archives for the paper I once offered illustrating...

What symptom or measurement has you thinking the CT is open-circuited? Regards, Phil Corso (cepsicon [at] aol.com)

Hasadam... 1) Is vibration period sympathetic with rpm. 2) Does vibration amplitude change with Gen Load? 3) Is vibration present when TG on turning gear, or when TG-set is slowing down? Regards, Phil Corso (cepsicon [at] aol.com)

Responding to Nimesh's 05-Aug-09 (0221) query: Underfrequency, mostly for Load-Shedding applications, has been considered an electrical system protection parameter. About 20-25 years ago, especially with the proliferation of larger ST and GT prime-movers, emphasisis on underfrequency...

Hussain, no, the plan I have in mind does not require reconnecting the generator to provide 3.5kV. Furthermore, the generator's full capacity will be available to you! However, if you are aware of my policy regarding anonymity, then send me your full name, your company affiliation, and your...

Hussain... the specs you have provided indicate maximum capacity at 6-kV is 15-MW, if the generator's rated pf is unity! If not unity, then the rated capacity, ignoring other yet to be revealed restrictions, could be as low as 6 MW. Are you sure the rated pf is unity? Regardless...

Hussain... the answer depends on a number of conditions... a major one being, "How much Power must be delivered at 3.3 kV?" Regards, Phil Corso (cepsicon [at] aol.com)

Responding to KKK's 28-Jul-09 (21:30) query... Search Control List Archives for: http://Control.com/thread/1026240308 "CTs in Series" Regards, Phil Corso (Cepsicon [at] aol.com

For Rob, re your request for photos... I received message that my reply to you was "undeliverable!" Do you have a 2nd email address? Phil

Excellent question... In most cases bi-directional current-flow, such as a tie-breaker in a secondary-selective configuration, is acceptable. But, this condition must be clearly specified to the manufacturer to include an assessment of what happens wnen the breaker is called upon to interrupt...

A second advantage is that its size is about 10% of that of a typical 3-phase transformer having the same kVA capacity. Phil Corso

Cephas... the simple answer is that it's an alternative to NGR and NGT methods! However, it has a decided advantage over the other methods. That is, internal losses, resulting from earth-current flow, are equally distributed amongst six wibdings! Regards, Phil

Responding to Astixjr's 20-Jul-09 (00:55) post... Following are a few questions, that may be helpful in "pointing" you in a direction to the solution: 1) What is kVA capacity of your plant's utility tranformer. 2) What are the "true" ph-to-ph voltages at: a) source bus; b) input terminal...

Shaft, if I understand you correctly you want to know how the SQRT[3] is derived? For simplicity I will define phase-to-neutral voltages as "phase" voltages, and phase-to-phase voltages as "line" voltages. Reverting to basics, the instantaneous phase voltage of a single-phase system is...

Responding to Viwapainc's 19-Jul-09 (15:38) query... before jumping the gun please provide some detail: 1) Prime mover? 2) Gen Parameters? 3) Load characteristics? 4) New or old problem? 5) Iso-operation, or in parallel w/other source? 6) If in sync with another source, is...