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R. Barrett... My comment was based on the sketch Randy1588 provided that showed just one 89nd switch used to connect the generator's neutral to ground. I would appreciate a sketch illustrating the 89ss to connect the LCI in your situation. Regards, Phil ([email protected])

Tmr, if a master trip occurred (not just a breaker trip) then: 1) Can you produce a chart showing the temperature vs time for each journal or thrust bearing during run-down and subsequent run-up periods? 2) Repeat for lube-oil temperature? 3) Repeat for lube-oil temperature 4) Total...

Sumeet, of course the current increases... it's zero without a fault. Is the meaning of your question, "Why not substitute a CT for the PT?" Regards, Phil Corso

tmr, what was the electrical disturbance that caused the initial trip? Regards, Phil Corso ([email protected])

Responding to Hemanth's 14-May-09 (08:34)query... Contact me off-list! Regards, Phil corso ([email protected])

Abhijit, further to my 11-May-09 (11:48), response to your query, please provide the following measurements to and from each drive: 4) Line-to-Line Voltages. 5) Line-to-earth Voltages. 6) Line Amperes. Please make sure you use a "true" rms reading meter! Regards...

Abhijit Saha, to start, please provide the following: 1) Supply voltage to your drives. 2) Size of supply transformer. 3) Is neutral of supply xfmr earthed? Regards, Phil Corso ([email protected])

Randy, thanks for the sketch. Recapping: 1) A wye-connected 18kV Generator is connected to a 500kV grid through a Yd step-up transformer ('Y' represents the HV winding and 'd' the MV winding.) 2) An ANSI Device #89 Line-Switch is located between the generator's neutral and ground...

What does your local gas/diesel supply station use? Regards, Phil Corso

Thanks CSA. Randy, one picture is worth a thousand words! Send a simple Single-Line-Diagram, even a pencil sketch, to me! Regards, Phil Corso ([email protected])

Bala, If it passes the Eye, Ear, Nose test, then the winding failed internally. Maybe resulting from the Ratio-Test. If you haven't already teken it apart, then send it back to the manufacture for analysis! Regards, Phil Corso

Hussain, 1) Within the last month, there has been a proliferation of articles questioning the use of the Insulation Resistance and (IR)Polarization Index (PI) for determining insulation integrity, on rotating equipment having Class F or H insulation. 2) In my view the single IR measurement...

Hussain, 1) Your 5,000 V meter is adequate. The point is to use the Tester to determine Dielectric-Absorption-Rate. Knowing just Insulation Resistance magnitude is not enough to reveal how "good" the insulation is! 2) Sorry, the thread number id # 1001509379 Phil Corso

Hussain, The readings are not "normal" which is obvious from the wide variation. Exacerbating the problem is that the so-called "spot-test" you carried out, without prior tests as a guide, can't really tell you how "good" the insulation is! The positive fact: the measurements are well...

Responding to Bala's 19-Apr-09 (13:13) query. 1) Only one metering CT failed? Or one of three CTs failed? 2) What was CT current rating? 3) What was current ratio? 4) What was secondary burden (VA)? 5) How was test performed? Was primary current applied gradually? Or some max...

Responding to JarJar's 18-Apr-09 (14:44) query: Yes, but far more meaningful advice could be offered if you provided additional info: 1) Genset' parameters. 2) Engen parameters; 3) Load characteristics. 4) Actual readings, such as V, I, Hz or Rpm, kW, kVAr, kVAr, RPM, and if...

Based upon the data you provided, the short answer is no! However, if you can access either transformer's internal connections, then the answer is yes. Additional details required? Regards, Phil Corso ([email protected])

Hussain, thank you for your reply. Regrding the variation in values: 1) How old is the generator? 2) What is the insulation material? 3) What is the environment in which it is operating? 4) Why was the test done? 5) Did you pre-heat the windings by applying low voltage to their...

Hussain, please provide addditonal detail. The six measurements numbers inicate, somehow, that you were able to isolate the three windings, that is, with respect to earth and to each other. Regards, Phil Corso([email protected])

1) From the observations made, the most probable cause of tripping is flame-loss detection by just one detector! 2) Can you provide some detail regarding the flame-loss logic? That is, does flame-loss by one detector on any level, initiate trippng? 3) Are the detectors paired, that is...