下圖所示形體的H面投影是()
A.選項(xiàng)AB.選項(xiàng)BC.選項(xiàng)CD.選項(xiàng)D
A.4B.5C.6D.7
A.輔助觸頭壓力不足B.定轉(zhuǎn)子間積塵太多或有鐵末C.接觸不良D.彈簧壓力過緊