Question 422Electricity & Electronics - Assistant Engineer

70% to pass

You are in the planning stages of replacing a battery charger, where an exact duplicate of the charger to be replaced is not available. Obviously the charger must be suitable for the battery to be charged. According to 46 CFR, Subchapter J (Electrical Engineering), which of the following is a true statement concerning battery chargers?

ABattery chargers incorporating grounded autotransformers must NOT be used, and if the charging voltage is less than 20% of the battery line voltage, automatic protection against reversal current must be provided.
BBattery chargers incorporating grounded autotransformers must NOT be used, and if the charging voltage exceeds 20% of the battery line voltage, automatic protection against reversal current must be provided.
CBattery chargers incorporating grounded autotransformers must be used, and if the charging voltage is less than 20% of the battery line voltage, automatic protection against reversal current must be provided.
DBattery chargers incorporating grounded autotransformers must be used, and if the charging voltage exceeds 20% of the battery line voltage, automatic protection against reversal current must be provided.
AI Explanation

The correct answer is B. According to 46 CFR Subchapter J, battery chargers incorporating grounded autotransformers must NOT be used, and if the charging voltage exceeds 20% of the battery line voltage, automatic protection against reversal current must be provided. This is because grounded autotransformers can create a potential safety hazard, and the 20% voltage threshold is to ensure the battery is not overcharged, which could damage the battery. The other options are incorrect because they either allow the use of grounded autotransformers (C and D) or have the voltage threshold reversed (A).

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