【判断题】改变旋转磁场的转向即可改变电动机的转向,即:任意交换接入定子绕组三相电源中的两相,电动机就会反转。
【单选题】I insisted he______ back the wallet to the lady, but he insisted he______it.
【判断题】三相电动机的正反转控制中,改变电动机三相交流电源中任意两相的相序,即可改变电动机的旋转方向。
【单选题】If he ___ that he ____ to work there, everything would be OK now.
D.
had insisted, was sent
【单选题】His father insisted _____ him, but he insisted he _____ nothing to do with the matter. [ ]
A.
on punishing; should have
D.
he punish; should have
【单选题】He insisted that his bike ______ stolen and his wife insisted he ______ have to telephone the police. [ ]
【简答题】电动机反转的方法 只需改变电动机旋转磁场的旋转方向,即改变输入电动机三相电源的 ( ),也就数 改变电动机任意两根引线的连接相序。
【判断题】在雾视时,应该让被检者平视看远,以减少调节因素造成的误差。