Question 268Electricity & Electronics - Assistant Engineer

70% to pass

Emergency generators are required to automatically start upon a loss of normal supply voltage, according to 46 CFR, Subchapter J (Electrical Engineering). In conducting a test of the emergency generator automatic transfer of load function, if the normal system supply voltage is 480 VAC, to what value would the normal source output voltage have to rise to trigger the automatic transfer of emergency loads back to the normal power source?

AIt would have to rise to 408 VAC.
BIt would have to rise to 456 VAC.
CIt would have to rise to a value from between 408 VAC to 456 VAC.
DIt would have to rise to a value from between 440 VAC to 460 VAC.
AI Explanation

The correct answer is C) It would have to rise to a value from between 408 VAC to 456 VAC. The explanation is as follows: According to 46 CFR, Subchapter J (Electrical Engineering), the emergency generator is required to automatically start and transfer the emergency loads when the normal power source voltage drops below a set value, typically between 408 VAC to 456 VAC for a 480 VAC system. This range allows for some voltage fluctuation while ensuring the emergency generator is activated to maintain critical systems. The other options are incorrect because they either fall outside the acceptable voltage range (A and D) or do not provide the necessary details (B).

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