Question 157Gas Turbine - Assistant Engineer

70% to pass

During an auto-start sequence on the marine gas turbine control console shown in the illustration, what would be the correct order of events required to occur after the start sequence begins? Illustration GT-0016

Diagram for USCG Gas Turbine Assistant: During an auto-start sequence on the marine gas turbine control console shown...
ANGG reaches idle RPM, Power turbine reaches ignition RPM, gas temperature greater than 400 degrees F.
BNGG reaches ignition RPM, gas temperature greater than 400 degrees F, NGG reaches idle RPM
CPower turbine reaches ignition RPM, gas temperature greater than 400 degrees F, Power turbine reaches idle RPM
DPower turbine reaches ignition RPM, gas temperature greater than 400 degrees F, NGG reaches idle RPM
AI Explanation

The correct answer is B) NGG reaches ignition RPM, gas temperature greater than 400 degrees F, NGG reaches idle RPM. During the auto-start sequence of a marine gas turbine, the first critical event is the NGG (gas generator) reaching its ignition RPM. This allows the fuel to be ignited and the turbine to begin generating power. Next, the gas temperature must rise above 400 degrees F to indicate successful ignition. Finally, the NGG must reach its idle RPM, indicating the turbine is operating at a stable, self-sustaining level. The other options are incorrect because they do not follow the proper sequence of events required for a successful gas turbine start-up.

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Official Resources
46 CFR Machinery & Electrical 46 CFR Engineering USCG National Maritime Center
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