问题
问答题 简答题
新安装或检修后的电动机启动时，速断或过流保护动作，可能是什么原因？
答案
参考答案：
可能的原因如下：
⑴被带动的机械有故障。
⑵电动机或电缆短路。
⑶绕线式转子电动机启动时滑环短路或变阻器不在启动位置。
⑷保护装置整定的动作电流太小，过流保护的动作时限不够。
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新安装或检修后的电动机启动时，速断或过流保护动作，可能是什么原因？
参考答案：
可能的原因如下：
⑴被带动的机械有故障。
⑵电动机或电缆短路。
⑶绕线式转子电动机启动时滑环短路或变阻器不在启动位置。
⑷保护装置整定的动作电流太小，过流保护的动作时限不够。
| 阅读理解。 |
| Parents are the closest people to you in the world. They love you just because you are their child. And they would do anything for you. Like many middle school students, Zhuang Shuxia has a problem. She and her parents don't get well. She said," I really want to be my Daddy's little girl. But it seems that he just doesn't understand me. He talks at me and doesn't listen to me." Do you and your parents also have the problem like this? May 15 is the International Day of Families. People around the world give thanks for good things about their families and work on family problems. Why don't you all take a walk and have a talk on that day? A report last year showed that among 2000 Beijing families, about 1500 students had the same problem as Zhuang. The children, 12 to 15 years old, didn't like talking with their parents much. They weren't happy at home. Of course, lots of children feel that way. But you and your parents will be much happier if you can be friends. Here are some ways to have a good talk with them: Find a good time to talk, for example, when you're eating dinner, going out for a walk or watching TV. Tell them something you're interested in, or ask them about their lives when they were young. They love to talk about that! Listen to them carefully, and look them in the eye. Be honest. Your parents will trust you more. And a trusting family is a happy family. |
| 1. When you have problems with your parents, you should _______. |
[ ] |
| A. have a good talk with them B. stay at home C. do what you are interested in D. don't go back home |
| 2. In the text the writer gives ______ ways to talk with parents. |
[ ] |
| A. two B. three C. four or more D. five |
| 3. Many students don't feel happy at home because . |
[ ] |
| A. they don't like talking B. their patents don't understand them C. they like watching TV D. they don't like English |
| 4. Does Zhuang Shuxia's father understand her? |
[ ] |
| A. Yes, he does. B. No, he doesn't. C. I don't know. D. Perhaps he does. |
| 5. Which of the following is true according to the text? |
[ ] |
| A. On May 15 people talk and work on family problems. B. Some children have problems while their parents don't. C. Most students, 12 to 15 years old, like talking with their parents. D. Most of children can't understand their parents but parents can understand them. |