Which one of the following will cause the most damage to the contact surfaces of a main generator output breaker?
A. An operator attempts to close the main generator output breaker with the generator and power grid frequencies matched but with voltages 180 degrees out of phase.
B. An operator attempts to close the main generator output breaker with the generator and power grid voltages in phase but with generator frequency 0.5 percent higher than power grid frequency.
C. The main generator output breaker automatically trips open on a loss of offsite power while the main generator is operating at its minimum rated load.
D. The main generator output breaker automatically trips open on a loss of offsite power while the main generator is operating at its maximum rated load.
Show Answer
Answer: A
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