A.40%~50% B.50%~60% C.40%~70% D.70%~100%
A.電壓負反饋 B.電流負反饋 C.電流正反饋 D.速度負反饋
A.磁極對數(shù) B.電源頻率 C.電刷位置 D.電源電壓