Which of the listed instruments can be best used to locate a grounded field coil in a synchronous motor onboard ship?
Official USCG Answer & Rule Citation
Correct Answer: Option A — Megohmmeter
A megohmmeter (megger) applies high DC test voltage to measure insulation resistance relative to the motor frame, making it the definitive instrument for locating grounded field coils. IEEE 45 and 46 CFR Subchapter J mandate periodic insulation resistance testing for marine rotating machinery.
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