Question 188Electricity/Electronics - QMED70% to pass
You are attempting to parallel two AC generators, and the synchroscope pointer is revolving in the fast direction. What is the frequency of the oncoming generator relative to the bus frequency?
AI Explanation
The correct answer is D) higher than the bus frequency.
When synchronizing two AC generators, the synchroscope pointer revolving in the fast direction indicates that the frequency of the oncoming generator is higher than the bus frequency. This is because the higher frequency generator is running ahead of the bus frequency, causing the synchroscope pointer to rotate in the fast direction.
The other options are incorrect because A) the frequencies must match for the circuit breaker to be closed, C) the frequencies must match in both frequency and phase for the circuit breaker to be closed, and B) a lower frequency oncoming generator would cause the synchroscope pointer to rotate in the slower direction.
Related Questions
#186 Which of the following statements is true concerning the operation of two alternators in parallel? #187 You are paralleling two alternators. The synchronizing lamps grow dim and are totally darkened as the synchroscope pointer approaches the 0° position. What does this indicate? #189 To remove an alternator operating in parallel with another unit from the main electrical bus, what must be done FIRST? #190 A main switchboard synchronizing panel is fitted with two synchronizing lamps and a synchroscope. When paralleling, if the synchroscope pointer is at the noon position and one synchronizing light is bright while the other remains dark, what does this indicate? #191 If the excitation of an alternator operating in parallel is decreased below normal and the other above normal, what will be the result on the alternator with the excitation decreased below normal?