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Jigs, The problem started when the IGV actuator was replaced during the outage. It's not clear if the electro-hydraulic servo-valve was also replaced at the same time, and if the proper servo-valve was used for the replacement, and if the polarity of the current applied to each coil was...

A "short" or even a ground of a 4-20 mA input will not be reported by the Mark V as a 125 VDC Battery Ground--or as a change in supply split voltage. That's because the (nominal) 24 VDC supply produced by the Mark V power supplies is isolated from the 125 VDC battery through transformers and...

The isothermal limit setting doesn't change if the backup (secondary) exhaust temperature reference becomes active. The differential shifts the (negatively) sloped portion of the curve to the right (if the Control Constants are calculated correctly). This would extend the isothermal limit to the...

Excellent basic explanation of MBC by Hans E. Eder. studmad, I presume you are or represent an owner or operators of gas turbines. The implementation of MBC for gas turbines is one OEM's way to differentiate its offering from other OEMs. First there was TMR, now there is MBC. And we all know...

sardar9, Yes; when operating in IGV Exhaust Temperature Control mode the IGVs are modulated based on the CPD-biased exhaust temperature reference. Your question about a failure of the CPD transmitter is a little unclear. Do you mean a complete loss of CPD feedback, or a higher-than-actual...

Mark Licari, I only want to address the real load portion of this discussion in this reply--the watts, not the VArs. In an electrical system the real power (watts; KW; MW) being produced/transmitted is a function of the voltage multiplied by the amperes multiplied by the square root of 3...

Ron, There are 100s of Voter Mismatch Diagnostic Alarms possible on any Mark V turbine control system. They can be related to logic signals or analog signals that are not directly related to inputs or outputs. They can be related to logic or analog signals directly related to inputs or...

Shams, Without MUCH MORE information we can't be too much help, and we a would really need to see the circuit drawing for the breaker close coil to be most helpful. It would also be very helpful to know specifically which relay is experiencing the burnt contact. We don't know anything...

Wajid Hussain, The liquid fuel supply piping must be clear of all air; this includes all the fuel filter canisters as well as all piping. Also, many liquid fuel forwarding systems have pressure regulators (some don't) and these pressure regulators generally require some adjustments to get...

anonymous112, Hmmm.... The number of analog outputs (servo outputs and 4-20 mA outputs) varies with each version of Mark Speedtronic, and the type of output also varies with the version of Mark Speedtronic. Your best source of information for the Mark V is the Mark V Application Manual...

Robert, Actually, the 505 manual by Woodward is not a bad manual at all. And most of the problems I've run into on 505 installations call into one of two categories: incorrect contact sense (NO, NC) specified by the application/design engineer, and problems determining control valve PID...

mectarek, The biggest criteria for selecting one starting means over any other should be reliability. If you choose a turbo-starter, will the medium passing through the turbo-starter ALWAYS be available for starting? The general reason diesel engines are used is that they don't require AC...

GE, Hmmmm..... Sometimes a Control Constant which may have been added in the field does not appear in alphanumeric order in the list of Control Constants in Data List 1D. You may have to scroll through all the screens of the Control Constant Display to find the ones you're looking for...

Later versions of the Mark IV Speedtronic asked the user to enter his/her initials (a one, two or three alpha-character set) to try to keep track of "who" made changes. Personally, I never used my initials (the first three characters of my first, middle, and last name); I just entered ZZZ to be...

Hi, You didn't tell us what was done during the recent service to the black start generator. Most prime movers these days (the device (engine) that drives the generator) have electronic governors that look at a frequency feedback from some kind of speed pick-up on the prime mover shaft and...

ABDI, When a GE-design Frame 9E heavy duty gas turbine (with or without DLN-I combustors) at 120 RPM on cooldown sequence after a trip from load, the IGV reference is 34 DGA (DeGrees Angle). To verify this, look at the IGV Display on the HMI and note that the reference value (the "setpoint")...

Wajid Hussain, In an effort to improve the zero speed detection capability of Speedtronic turbine controls (especially the Mark VI and Mark VIe versions) GE has modified the algorithm used in the speed detection input circuits of both the turbine shaft speed pick-ups and the liquid fuel flow...

jj, Usually when this happens during manual synchronization it's because the voltage matching isn't done correctly resulting in excessive reactive current (usually leading) at some point in the system. To understand why a particular breaker is opening you need to look at the breaker trip...

Abdi, Duct burners are rarely intended to be used at any load other than Base Load. That's why there are interlocks to prevent using duct burners at loads less than Base Load. One of the defining conditions of Base Load is that the IGVs are at their maximum operating angle ("full open")...

Priuyanka, This specification is for a solenoid-operated valve--a device that controls the flow (on/off) of air through a valve that is opened/closed by the de-energization or energization of an electromagnetic solenoid coil. The spec seems to be describing a normally open...