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 450 VAC, to what value would the emergency generator output voltage have to rise to trigger the automatic transfer of emergency loads to the emergency generator?

Question

Accepted Answer

Option A: The voltage would have to rise to a value between from 382.5 VAC to 427.5 VAC.. Per 46 CFR Subchapter J, emergency generator automatic transfer occurs when terminal voltage reaches 85% to 95% of nominal (382.5 to 427.5 VAC on a 450 VAC system) after starting.