Question 183Electricity & Electronics - QMED

The correct answer is B) the synchroscope is defective or broken. When paralleling two alternators, the synchronizing lamps should go out as the synchroscope pointer approaches the 0° position, indicating that the voltages, frequencies, and phase angles of the two alternators are properly synchronized. If the synchronizing lamps remain lit as the synchroscope pointer approaches 0°, it indicates that the synchroscope is not functioning correctly and is not accurately displaying the phase relationship between the two alternators. The other answer choices are incorrect because: A) the alternator voltages being 180 degrees apart would cause the synchronizing lamps to remain lit, but this is not the expected behavior; C) the incoming alternator running too fast would cause the synchroscope pointer to move past the 0° position, not remain at 0°; and D) the alternator power factors being in phase would not explain the synchronizing lamps remaining lit.