【单选题】三相异步电动机出现外壳带电的故障时,则造成故障的原因应该为( )
【单选题】根据GB/T18488.1-2015驱动电机控制器中能触及的可导电部分与外壳接地点处的阻值不应该大于()
【单选题】Students are handing ou t information booklets.
【单选题】某三相异步电动机运行于中心点接地的三相四线制交流电源上,为保证电动机的安全运行,该电动机的金属外壳应与()。
【多选题】鲁迅说:“本草家提起笔来,写:砒霜,大毒。字不过四字,但他却知道了这东西曾毒死过若干性命的了。”这说明()。
【简答题】Pair work Talk
about free-time
activities with your
partner. You can take turns asking your partner the following questions. 1. What do you usually do in your free time? 2. What’s your favorite free-t...
【单选题】What do you think of the two hotels in the town?
A.
One is better than the other.
B.
They are not the same in size.
C.
Both of them are not good.
D.
Neither of them is good.
【简答题】起动机主接柱 30 端与蓄电池负极之间的电压应该为 +B ,与起动机外壳之间的电压为 0V ,说明( )
【多选题】连接电动机械及电动工具的电气回路应该()。