单项选择题
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
单项选择题 To repair a small electrical motor that has been submerged in saltwater, you should （）.
单项选择题 A fuse that blows often should be replaced only with a fuse of （）.
单项选择题 A constant output voltage from an AC generator is maintained by the （）.
