A.只有定子磁勢,而無轉(zhuǎn)子磁勢 B.只有轉(zhuǎn)子磁勢,而無定子磁勢 C.既有定子磁勢,也有轉(zhuǎn)子磁勢 D.既無定子磁勢,也無轉(zhuǎn)子磁勢
A.80% B.90% C.95% D.100%
A.圓柱齒輪 B.圓錐齒輪 C.蝸輪與蝸桿