单项选择题
A.larger and heavier than B.as much as C.smaller and lighter than D.more dangerous than
The star formation is most commonly used and requires（）...
单项选择题The star formation is most commonly used and requires（） on the alternator.
A.one slip-ring B.two sliprings C.three sliprings D.four sliprings
The field coils（） and the armature is（）This is in fact ...
单项选择题The field coils（） and the armature is（）This is in fact the arrangement adopted for large, heavy duty alternators.
A.stationary；rotate B.stationary；stationary C.rotate；stationary D.rotate；rotate
The power factor is a measure of the phase difference b...
单项选择题The power factor is a measure of the phase difference between voltage and current and is expressed as the（） of the phase angle.
A.sine B.cosine C.tangent D.cotangent
