相关试题
【单选题】
三相异步电动机通电后不转且有嗡嗡声，可能的原因是___
A. 三相电源缺一相
B. 三相电源缺两相
C. 三相电源相序接错
D. 电源频率不对
【单选题】
直流电动机换向极的作用是___
A. 削弱主磁场
B. 增强主磁场
C. 抵消电枢反应
D. 产生主磁场
【单选题】
直流电动机电枢导体内的电流是___
A. 直流
B. 脉动直流
C. 交流
D. 不定
【单选题】
电容如果串入单相异步电动机工作绕组中会发生的现象是___
A. 电动机反转
B. 电动机立刻烧掉
C. 电动机正常运行
D. 电动机转向不变，但转速增大
【单选题】
电风扇电机和冰箱压缩机是单相异步电动机，它们的运行方式分别是___
A. 单相电容运行电动机，单相电容启动电动机
B. 单相电容运行电动机，单相电阻启动电动机
C. 单相电阻启动电动机，单相电容运行电动机
D. 单相电容启动电动机，单相电阻启动电动机
【单选题】
工业生产企业中应用最广泛的电动机是___
A. 直流电动机
B. 三相笼型异步电动机
C. 三相绕线式异步电动机
D. 三相同步电动机
【单选题】
三相异步电动机在运行时出现一相电源断电，对电动机带来的影响主 要是___。
A. 电动机立即停转
B. 电动机转速降低、温度升高
C. 电动机出现振动及异声
D. 电动机反转
【单选题】
欲使接触器KM1动作后接触器KM2才能动作，需要___。
A. 在KM1的线圈回路中串入KM2的常开触点
B. 在KM1的线圈回路中串入KM2的常闭触点
C. 在KM2的线圈回路中串入KM1的常开触点
D. 在KM2的线圈回路中串入KM1的常闭触点
【判断题】
一台直流发电机若把电枢固定，而电刷与磁极同时旋转，则在电刷两端仍能得到直流电压
【判断题】
直流电动机串多级电阻起动，在起动过程中，每切除一级起动电阻时，电枢电流都会突变
【判断题】
一台变压器原边电压U1不变，副边接电阻性负载或接电感性负载，如负载电流相等，则两种情况下，副边电压也相等
【判断题】
变压器在原边外加额定电压不变的情况下，副边电流大，导致原边电流也大，因此变压器的主磁通也大
【判断题】
交流发电机正常发电以后可以断掉直流励磁电源
【判断题】
改变电流相序可以改变三相旋转磁通势的转向
【判断题】
不管异步电动机转子是旋转，还是静止，定、转子磁通势都是相对静止的
【判断题】
三相异步电动机的最大磁通势Tm 的大小与转子电阻rm 阻值无关
【判断题】
三相异步电动机的变极调速只能用在笼型转子电动机上
【填空题】
1、 他励直流电动机的机械特性是指在___的条件下 ___ 和 ___ 的关系。
【填空题】
2、直流电动机的起动方法有： ___ 和 ___ 。
【填空题】
3、变压器带负载运行时，若负载增大，其铁损耗将 ___ ，铜损耗 ___ {忽略漏磁阻抗压降的影响}。
【填空题】
4、当变压器负载{φ2>0˚}一定，电源电压下降，则空载电流I0___ ，铁损耗PFe ___ 。
【填空题】
5、三相异步电动机根据转子不同可分为 ___ 和 ___ 两类。根据磁滞回线 ___ 的大小，铁磁材料分为硬磁材料和软磁材料。
【填空题】
6、 电力拖动系统是由 ___ 拖动机械机构工作的系统。
【填空题】
7、直流电动机的励磁方式包括 ___ 、___、___和 ___ ，其中 ___ 直流电动机更适合于电动机控制的场合。
【填空题】
8、直流电机电枢磁场对空载主磁场的影响称为 ___ 。
【填空题】
9、励磁绕组断线的他励直流电动机，空载起动时，将出现 ___ 情况。
【填空题】
10、三相交流绕组通入对称的三相交流电流将产生 ___ 不变，空间旋转的磁动势。如果想要改变磁场的旋转方向，可以通过改变 ___ 来实现。
【填空题】
11、三相异步电动机参数测定实验中，空载实验的损耗包括定子铜损、 ___ 和 ___ 。实验过程中， ___是不变损耗。
【填空题】
12、在同步电机的励磁系统中，无刷励磁系统指的是 ___ 整流器励磁系统。
【填空题】
13、单相交流绕组通入单相交流电流将产生 ___ 不变，幅值变化的磁动势。如果想要获得恒定的磁场，可以在绕组中通入 ___ 来实现。
【填空题】
14、三相异步电动机Y132M-4，60Hz，转差率为0.04，则转速为 ___ ，转子侧频率为 ___ ，该电机处于 ___ 运行状态。
【填空题】
15、三相异步电动机参数测定实验中， ___ 为提前获得的参数，参数测定实验包括 ___ 实验和 ___ 实验。
【多选题】
党的思想路线的基本内容是___
A. 实事求是
B. 一切从实际出发，理论联系实际
C. 从群众来到群众中去
D. 在实践中检验真理和发展真理
【多选题】
在理论与实践的关系上，中国共产党在历史上曾经存在过两种错误倾向___
A. 教条主义
B. 冒险主义
C. 经验主义
D. 保守主义
【多选题】
毛泽东思想活的灵魂有三个基本方面___
A. 实事求是
B. 群众路线
C. 独立自主
D. 自力更生
E. 统一战线
【多选题】
以下哪些属于毛泽东思想的主要内容___
A. 新民主主义革命理论
B. 社会主义革命和社会主义建设理论
C. 旧民主主义革命理论
D. 革命军队建设和军事战略理论
【多选题】
毛泽东思想是___
A. 马克思列宁主义在中国的运用和发展
B. 被实践证明了的关于中国革命和建设的正确的理论原则和经验总结
C. 中国共产党集体智慧的结晶
D. 发展中国特色社会主义必须坚持和贯彻的重大战略思想
【多选题】
毛泽东思想形成和发展的特点有___
A. 是马克思列宁主义与中国实际相结合的产物
B. 是毛泽东等人主观创造出来的
C. 是在同错误的理论和实践的斗争中形成和发展起来的
D. 形成和发展的过程就是马克思主义中国化的过程
E. 是照搬马克思列宁主义全部理论成果
【多选题】
毛泽东把"实事求是"确立为中国共产党的思想路线，这条思想路线是在___
A. 毛泽东领导中国革命的实践中形成和发展起来的
B. 在反对把马克思主义教条化的斗争中形成和发展起来的
C. 在反对把苏联经验绝对化的过程中形成和发展起来的
D. 在反对把共产党国际的指示神圣化的斗争中形成和发展起来的
E. 在纠正"文化大革命"的错误运动中形成和发展起来的
推荐试题
【单选题】
Tom is a book lover. ______ likes reading very much.
A. He B. She C. You D. It
【单选题】
—May I listen to the music here, Mr. White?
—Sorry, you’d better it like that．
A. not to do B. not do to
C. dont do D. not do
【单选题】
3.—Did you have a good time at Lauras birthday party?
— Yes, indeed. Its several years ________ I enjoyed myself so much.
A. when B. before C. since D. that
【单选题】
4. —___________ is the Summer Palace from here?
About three kilometers away. You can take the No. 35 bus.
A. How long B. How far C. How often D. How much
【单选题】
5. I was looking for a birthday gift for my mother, but I couldnt find ______ suitable.
A. anything B. something C. nothing D. everything
【单选题】
6. A friend of my ____ and I are going to visit_______ next week．
A. father; Browns B. father's; Browns
C. father; the Browns D. father's; the Browns
【单选题】
7. She ______ very hard since she came to our school.
A. studies B. has studied C. is studying D. studied
【单选题】
8. — Who will send you to the new school, your mom or your dad?
— _______. Ill go there by myself.
A. Both B. Either C. Neither D. None
【单选题】
9.—Well do what we can ____English well this term．
—It’s high time for you to work hard．
A. study B．to study C. be studied D. be studying
【单选题】
10. —I’m going to Flower Bookstore. Could you tell me ______?
— Sorry, I don’t know. I’m new here.
A. where it is B. where was it C. where is it D. where it was
【单选题】
11. How do you like the dishes, Eric?
— Fantastic! Nothing tastes ________.
A. nice B. better C. terrible D. worse
【单选题】
12. ______ Lin Feng has to work late, she always wears a smile on her face.
A. Because B. If C. Until D. Though
【单选题】
13.You can save money _______ you buy cheaper things.
A. before B. unless C. if D. until
【单选题】
14. We will have a _________ holiday after the exam．
A. two-month B. two month’s C. two month D. two-months
【单选题】
15. —We will build an underground in Xuzhou before 2015．
— Wow, _______! Will it pass our place?
A. what an excited news B. how excited the news is
C. what exciting news D. how exciting
【单选题】
16. — Emily, here’s a dictionary．I hope it will help you in some way．
— Thank you．It’s ________ what I need．
A. almost B. still C. only D. just
【单选题】
17. —Oh．I’m hungry．Mum, can I have the hamburger on the plate?
—No．It tastes ．
A. terribly B. terrible C. good D. well
【单选题】
18. —We can invite our teachers to the farewell party next Saturday.
—Yes, ______? I’ll call them at once.
A. what for B. what C. why not D. why
【单选题】
19.You can ________ ask the old man to move away to any other place because he has lived ________ here for at least sixty years．
A. hardly; alone B. hard; alone
C. hardly; lonely D. hardly; lonely
【单选题】
20.—I’m going back to see my grandparents this weekend．
—________．
A. It’s very nice of you B. You’d better hurry
C. Say goodbye to them D. Give my best wishes to them
【单选题】
21.—Why not take ____ umbrella with the sign “Made in China”? It is useful.
—What _______ good advice it is!
A. an; a B. a; a C. an; \ D. \; a
【单选题】
22. —Do you know the boy________ is sitting next to Peter?
— Yes. He is Peter’s friend. They are celebrating his ________ birthday.
A. who; ninth B. that; ninth C. /; ninth D. which; ninth
【单选题】
23. It was dark, ______ I couldnt see what was happening.
A. or B. though C. but D. so
【单选题】
24.—You can use MSN to talk with Vivien on the Internet.
—I know. But can you tell me ________?
A. what I can use it B. when I can use it
C. why can I use it D. how can I use it
【单选题】
25. _______ are you going to the School Uniform Exhibition, Amy ?
To learn about different styles of school uniform.
A. What B. Where C. Which D. Why
【单选题】
( ) 26. Where does the writer of "The little Prince" come from?
A．England． B．France． C．America． D．China．
【单选题】
( ) 27. What does the prince do after the fox tells him a secret?
A．He cares more about a flower and a sheep．
B．He meets many more strange adults on other planets．
C．He realizes his love for the rose and he goes back to his planet．
D．He discovers interesting things such as a snake, other roses and a fox
【单选题】
( ) 28. What does "The little Prince" mainly talk about? It' s about _________．
A．the adult world B．the planet B -612
C．a rose and a fox D．the adventure of a young prince
【单选题】
( ) 29. What is the writer's main purpose（目的）in writing this passage？
A．To tell the readers his life story．
B．To tell people what kind of person his father was．
C．To tell the readers what present he got from his father．
D． To let people know how poor he was．
【单选题】
( ) 30. Why did the father not ask his son not to do this and do that？
A．Because he felt quite confident of his son．
B．Because he was born from a poor family．
C．Because he was a man of few words．
D．Because he didn't want to be much too strict with his son．
【单选题】
( ) 31. What would someone learn from this passage？
A．How to live by oneself． B．How to stand on one's own feet．
C．What a good father should do． D．What the self-important is like．
【单选题】
( ) 32. What may be the proper Chinese for the underlined part in the passage？
A．闲暇时光 B．学费 C．精神空虚 D．经济不足
【单选题】
( ) 33. Why did Natalie Smith pay for the six cars behind her?
A. She had seven tickets.
B. She hoped to please others.
C. She knew the car drivers well.
D. She wanted to show kindness.
【单选题】
( ) 34. Judy Foreman copied down the phrase because she ___ .
A. thought it was beautifully written
B. wanted to know what it really meant
C. decided to write it on a warehouse wall
D. wanted her husband to put it up in the classroom
【单选题】
( ) 35. Who came up with the phrase according to the passage?
A. Judy Foreman. B. Natalie Smith. C. Anne Herbert D. Alice Johnson.
【单选题】
( ) 36. What can we infer from the last paragraph?
A. People should practice random kindness to those in need.
B. People who receive kindness are likely to offer it to others.
C. People should practice random kindness to strangers they meet.
D. People who receive kindness are likely to pay it back to the giver.
【单选题】
( ) 37.The greatest river for navigation is ___________.
A. the Nile B. the Amazon C. the Mekong D. the Mississippi
【单选题】
( ) 38. From a dam, people can use the water for ___________.
A. keeping the rivers clean B. only making electricity
C. irrigation and making electricity D. washing clothes
【单选题】
( ) 39. The water in the river is polluted because of _____________.
A. people's drinking water too much B. people's swimming in the river too much
C. chemicals and other materials D. people's building a dam across a river
【单选题】
( ) 40. The best title of the passage is ___________.
A. Rivers in Cities B. The importance of Rivers
C. Transportation D. Natural Resources
