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单选题
The output voltage of a three-phase alternator is regulated by the （）.
A
AC voltage to the armature
B
AC voltage to the field
C
DC voltage to the armature
D
DC voltage to the field
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单选题A three-phase alternator operates at 450 volts with a power factor of 0~8.If the ammeter indicates 250 amperes, what should be the KW meter reading （）.A
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