USCG Exam PracticeHand/power tools, measuring instruments, and maintenance
When trending megger readings on a shipboard motor over time, a watchstander should be aware that insulation-resistance values are strongly affected by which two factors?
- A. Supply voltage and motor speed
- ✓ Temperature and moistureCorrect
- C. Load current and power factor
- D. Phase sequence and frequency
Why B is correct
NEETS Mod. 3 §1-3 states that insulation-resistance readings are strongly affected by temperature and moisture; meggering is therefore done on warm, dry equipment where possible, and values are corrected and trended over time rather than judged against a single pass/fail number.
Cited:NEETS Mod. 3 §1-3