单项选择题

Current changing in direction and rising and falling in value is （）.

A.AC
B.DC
C.generator
D.fresh water generator

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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 （）.

A.wash it with fresh water and apply an external source of heat
B.renew the windings
C.send it ashore to an approved service facility
D.rinse all electrical parts with a carbon tetrachloride cleaning solvent and then blow dry the motor with compressed air

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A fuse that blows often should be replaced only with a fuse of （）.

A.the recommended current and voltage rating
B.higher current and voltage rating
C.higher current and lower voltage rating
D.lower current and higher voltage rating