问题
问答题 简答题
三相异步电动机的旋转磁场是怎样产生的？
答案
参考答案：三相异步电动机的旋转磁场是在三相对称定子绕组中接入三相交流电，由于每相交流电各产生一脉动磁场，三者的合成就形成一旋转磁场。
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三相异步电动机的旋转磁场是怎样产生的？
参考答案：三相异步电动机的旋转磁场是在三相对称定子绕组中接入三相交流电，由于每相交流电各产生一脉动磁场，三者的合成就形成一旋转磁场。
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| I live in a big city. It’s noisy and dirty and I always feel very 1 . At the weekends I like to leave the city and get some 2 air and have a good rest. A few weeks ago I decided to go see my 3 . I was really looking forward to it. My parents live a long way away. I went to see them with James, a friend of _4 . And we drove there on Friday night. In the middle of the trip it began to rain. The roads became very wet and it was difficult to 5 . We 6 home just after midnight, feeling very tired. The next morning it was still raining. James took his car to a garage(汽车修理站)which was very good. In the afternoon the 7 got better. We wanted to go for a drive. My parents_8 us their car. But their car wasn’t very goo  d. It didn’t 9 on the way. How 10 we were! We had to ring up the garage. “Oh”, they said, “your car won’t 11 until tomorrow. ”So it wasn’t 12 for us to go for a drive. We had to stay at my parents’ home all day. On Sunday my mother 13 a heavy box on her foot and we had to hire(雇佣)a taxi 14 her to hospital. When James and I drove back home on Sunday afternoon, we got stuck(堵车)in a car accident. Oh, my God! Next time if 1 want a rest, I’11 stay 15 . | |||
| ( )1. A. energetic ( )2. A. cold ( )3. A. classmates ( )4. A. I ( )5. A. ride ( )6. A. arrived at ( )7. A. sky ( )8. A. 1ent ( )9. A. move ( )10. A. 1uckily ( )11. A. be repaired ( )12. A. easy ( )13. A. put ( )14. A. to bring ( )15. A. in the country | B. surprised B. cool B. friend B. me B. drive B. arrived in B. earth B. borrowed B. begin B. 1ucky B. be repair B. possible B. threw B. to take B. in the city | C. happy C. dry C. parents C. mine C. walk C. arrived C. weather C. 1end C. start C. unlucky C. repaired C. necessary C. drop C. bring C. in the mountain | D. tired D. fresh D. neighbours D. my D. drove D. got to D. work D. borrow D. work D. unluckily D. been repaired D. right D. dropped D. take D. in the village |