Question 70Electricity & Electronics - Assistant Engineer

The correct answer is A) when the generators are in synchronism. When paralleling AC generators using synchronizing lamps, the lamps will go dark when the generators are in synchronism, meaning their voltage, frequency, and phase are matched. This is because when the generators are perfectly synchronized, there is no potential difference between them, and the synchronizing lamps will no longer have a voltage to light them up. The other options are incorrect because B) and D) describe situations where the generators are not in synchronism, and C) is incorrect since the lamps going dark indicates the generators are in synchronism, not out of synchronism.