单选题Self-excited a-cgenerator with "error operated" voltage control systems draw the full excitation power for the machine terminalsThis dispenses with the current transformers, reactors and capacitors necessary for accurate compounding, but renders the excitation system vulnerable to variations in its output voltageWhich of the following is correct about the generator mentioned according to the sentences above （）.AIt consumes no excitation powerBIt has current transformersCComponents are needed for accurate compoundingDIts excitation system is vulnerable to voltage variations
单选题
Self-excited a-cgenerator with "error operated" voltage control systems draw the full excitation power for the machine terminalsThis dispenses with the current transformers, reactors and capacitors necessary for accurate compounding, but renders the excitation system vulnerable to variations in its output voltageWhich of the following is correct about the generator mentioned according to the sentences above （）.
A
It consumes no excitation power
B
It has current transformers
C
Components are needed for accurate compounding
D
Its excitation system is vulnerable to voltage variations
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