国开电大专科《电气传动与调速系统》网上形考任务试题及答案
国家开放大学电大《电气传动与调速系统》网络课判断题答案
最新国家开放大学电大《电气传动与调速系统》网络课判断题答案判断题题目1当传动系统做旋转运动时，作用在电动机轴上的电磁转矩T和负载转矩TL之差，即T-T>AT称为动态转矩，当△T>0,即dn/dt > 0时，系统处于加速运行状态。
（）选择一项：对错题目2如图所示的负载机械特性属于恒功率负载机械特性。
（）选择一项：对错题目3如图所示的电动机机械特性（曲线1）与负载机械特性（曲线2）相交的交点分别为C、D和E,则C点不是稳定运行点,D点是不稳定运行点，E点是稳定运行点。
（）o选择一项：对错题目4直流电机的主磁极是产生电动势的部件。
（）选择一项：对错题目5直流电动机工作时，其电枢绕组中的电流是交流电流。
（）选择一项：对错题目6直流电动机的转速大小与励磁电流大小、电枢回路电阻值和所加电源电压的极性有关。
选择一项：错题目7如图所示为他励直流电动机的机械特性曲线组，表示的是电枢回路串电阻的人为机械特性。
（）选择一项：对错题目8如图所示为他励直流电动机四象限运行的机械特性曲线，曲线1是正向电动运行状态，曲线2是能耗制动运行状态，曲线3是反向电动运行状态。
（）选择一项：对错题目9三相异步电动机的转子绕组分为笼型转子和绕线型转子两类。
（）选择一项：对错题目10一台4极三相异步电动机，定子电流频率为50Hz,电机正常运行时的转差率s为0.02,则该电机定子旋转磁场与转子之间的相对转速为30r/min。
（）选择一项：对错题目11三相异步电动机的人为机械特性如图所示，该图表示的是降低电源电压的人为机械特性。
（）选择一项：对错题目12三相异步电动机能耗制动时的机械特性不经过原点，但位于第二、四象限内。
（）选择一项：对错题目13三相异步电动机的调速方法有：变极调速、变频调速和弱磁调速。
选择一项：对错题目14隐极同步电动机的定子电压方程为。
（）选择一项：对错题目15凸极同步电动机的电磁转矩与功率角之间的关系（矩角特性）可表示为。
国家开放大学电大《高级英语阅读(1)》《电气传动与调速系统》网络课形考网考作业(合集)答案
国家开放大学电大《高级英语阅读(1)》《电气传动与调速系统》网络课形考网考作业(合集)答案国家开放大学电大《高级英语阅读(1)》《电气传动与调速系统》网络课形考网考作业(合集)答案《高级英语阅读(1)》网络课答案形考任务一（70分） Chapter 1 Exercise （分值7分）题目1 I. Vocabulary skills（3 points）Look at the columns below. Match each vocabulary word on the right with the correct definition on the left.(0.5 points each) 1.the bus or subway 2.proof of completion of courses of students 3.money for students from scholarships, grants, or loans 4.formal talks by professors or instructors on subjects of study5.courses by video, video conferencing, or computers to students in different places6.the points or grade a student gets on a test 答案： II. Reading Comprehension (4 points) Read the passages, then answer the questions that follow. (1 point each ) Experiencing Culture Shock A When Eliza James arrivedat the University of Xian, she was excited to live in a new country, to improve her Chinese, and to experience a culture so different from her own. But soon her excitement turned to frustration as she encountered one roadblock after another. “I felt like I couldn＇t accomplish anything. My dorm room had no heat, I couldn＇t get into the classes I wanted, and every time I asked someone for help they gave me the runaround. I felt like no one was listening tome.“ Eliza met with adm inistrators, sent letters of complaint, and even contacted the consulate in Beijing, but she got nowhere. What Eliza didn＇t realize wasthat her American approach to solving problems wasvery different from the Chinese one in which patience and negotiation skills are key. She soon learned howto solve problems within the cultural norms of Chinese society instead of forcing her own values onto those around her. “I finally feel like I fit in and that I know what I＇m doing. In fact, it＇s really fun being in a place that＇s so incredibly different from what I am accustomed to.“ B Yoshi Yamamoto is a junior at asmall college outside of Boston. Although he is an honors student now, Yoshi didn＇t always have such an easy time studying in America. “Teaching methods are very different here than they are in Japan. It took me a long time to get used to learning in seminars and discussing ideas with my classmates. At first it seemed like I wasn＇t actually learninganything.“ Yoshi＇s reaction was to totally withdraw: he didn＇t participate in class discussion; he spent lots of time alone in his room, and he even skipped class on occasion. “I thought I could teach myself. Now I recognize the value of the U.S. academic system, and I am able to adapt it to my own learningstyl e.“ C Both Eliza and Yoshi experienced what is called culture shock: psychological disorientation due to living in a new culture. For many international students, studying abroad can offer exposure to new cultures and an opportunity to study new fields and languages. However, it also offers the greater challenge of trying to function in a foreign culture. Studying and reading about a certain culture is poorpreparation for the reality of living in it. According to psychological studies, the four stages of culture shock are 1. euphoria, 2. hostility, 3. gradual adjustment, and 4. adaptation. Culture shock can be manifested in many ways: homesickness, boredom, stereotyping of or hostility towards the host culture, overeating or overdrinking, withdrawal, and inability to work effectively. D Different people experience different levels of culture shock and react in different ways. For example, Eliza got angry while Yoshi withdrew from society. The most important thing to remember is that culture shock is normal; it is not something to be ashamed of. Luckily, there are some things international students can do to make their adjustment to a new country go more smoothly. For instance, they can stay in touch with family and friends from home, join international student organizations, meet people from their own countries, and get involved in campus activities. Most importantly, they can adjust to life abroad by keeping a sense of humor and trying to remain positive.Recognizing Paragraph Topics（choose the paragraph letter）题目2 7. an explanation of culture shock 选择一项： A. A B. B C. C D. D 题目3 8. ways that students can adjust to living in a new country 选择一项： A. A B. B C. C D. D 题目4 9. the experience of an international student in the United States 选择一项： A. A B. B C. C D. D 题目5 10. the experience of an international student in China 选择一项： A. A B.B C.C D.D Chapter 2 Exercise（分值7分）题目1 I. Vocabulary Skills（2 points） Sometimes examples can explain the meaning of a word or phrase. For example, sun, rain, and wind are examples of kinds of weather. Look at the columns below. Match each vocabulary word or phrase in the first column with the examples in the second column. (0.4 points each) 1.kinds of extreme weather 2.Earth’s natural materials and gases 3. diseases or health disorders 4. seasons of the year 5. natural areas or regions of the earth 答案： II. Reading Comprehension (5 points) Complete thefollowing statements by choosing the best from the answers A, B or C. (1 point each) Seasonal AffectiveDisorder: More than Just the Blues A Joshua dreads the winter months, not only because of the cold New England weather--the sleet, snow, wind, and rain--but because as the seasons change from summer to fall to winter, the days get shorter. As the days get shorter, he starts feeling depressed and irritable and spends more and more time at home, eating and sleeping. A graduate student in philosophy, Joshua finds that he gets little work done during the winter months and has trouble paying attention in class and concentrating on his research. “I soon realized that what I thought was just the ＇winter blues＇ was something more extreme than that.“ Josh visited a doctor who diagnosed him with SAD. B Seasonal Affective Disorder, or SAD, is a kind of depression that occurs seasonally. It is associated with the long hours of darkness and lack of sunlight during the winter months (people with SAD usually feel worse from December through February). Scientists don＇t completely understand the exact causes of SAD, but they believe it is related to a biochemical imbalance in the hypothalamus. Thehypothalamus is the basic part of the brain that controls the body＇s breathing, heartbeat, metabolism, and hormone release. The effects of SAD include moodiness, irritability, low energy, increasedappetite for carbohydrates (foods such as potatoes, rice, and bread), difficulty concentrating, and the tendency to oversleep. C Although doctors described SAD for the first time in 1984, humans have probably dealt with the disorder for thousands of years. It is not a coincidence that many cultures have important celebrations during the short days of the winter months. Christmas, Hanukkah, and Winter Solstice celebrations all occur in December. These celebrations involve lighting candles in order to bring light, warmth, and happiness to an otherwise depressing time of year. D So what can SAD sufferers do to feel better Naturally, they need more light. For people who have mild cases of SAD, exercising in the morning sun could be enough to help them. Phototherapy, or light therapy, is usually prescribed for people who have more serious cases of the disorder. In light therapy, patients sitin front of a light box, a strong artificial light,for up to four hours a day. Phototherapy is effectivein over 80% of SAD cases, and patients usually seeresults within three to four days. Although thesymptoms of SAD are similar to those of clinical depression, traditional antidepressants have notproven useful in treating SAD. While psychological counseling cannot treat the symptoms of SAD, it is recommended to help SAD sufferers learn to accept anddeal with their illness. 题目2 6. Joshua startsfeeling depressed and irritable in the winter because 选择一项： A. he gets little work done B. he suffersfrom Seasonal Affective Disorder C. he is a graduate student in philosophy 题目3 7. Seasonal Affective Disorder, or SAD, is a condition that researchersbelieve affects people during the winter months.Scientists believe it is caused by 选择一项： A. breathing, heartbeat, metabolism, and hormone releaseB. moodiness, irritability, loss of energy, increased appetite, difficulty concentrating, and sleepinessC.lack of sunlight and a biochemical imbalance in thebrain 题目4 8. Humans have probably struggled with SAD since 选择一项： A. ancient times B. December C. 1984 题目5 9. People who suffer from SAD can to feel better. 选择一项： A. do light therapy B. take antidepressant drugs C. eat carbohydrates 题目6 10. This passage talks about_____. 选择一项： A. what the SAD effects are B. Both A and B. C. how to help SAD suffers Chapter 3 Exercise（分值7分） I. Reading Comprehension (5 points) Read the passages, then answer the questions that follow. (1 point each ) Fast food can be good food Many people are too busy to prepare and eat three nutritious meals a day.so they turn to the convenience of fast-food restaurants. Many of the items at fast-food restaurants, snack bars, and food stands are fattening and not very nutritious.But fast food doesn’t have to be unhealthy.you can eat at fast-food restaurants and still eat well. PayAttention to Calories and Fat Content By paying attention to the number of calories and fat that a food item has ,you can make smarter choices.Calories are “units for measuring how much energy a food willproduce”.condsider two fa st-food meals. A quarter-pound hamburger with cheese, jumbo-size fries,and a16-ounce soda have a total of 1,535 calories and 76 grams of fat .a broiled (cooked under direct heat or over a flame )chicken sandwich ,a side salad with low-fat dressing,and a glass of water at the same fast-food restaurant have only 422 calories and 7 grams of fat .but maybe you really want a hamburger andfries .well,you can have a small hamburger,a small serving of fries,and a glass of water.At a total of 490 calories and 20 grams of fat,that’s still a much smarter choice than the large burger ,fries,and 20 grams of fat ,that’s still a much smarter choice than the large burger,fries,and sada. There’s More That You Can Do There are a few additional things you can do to make sure you eat well in fast food restaurantS.First of all,say “no” when the cashier asks you if you want to “supersize” you meal (order an extra large portion of each item).Second, ask for no mayonnaise or sauce,or ask for it on the side (in a separate dish).Third,substitute(use something insteadof something else)healthy foods for fatty ones. For example,instead of ordering deep-fried tempura,order fresh vegetables.Instead of ordering a beef burrito with lots of cheese and sour cream,order a vegetable burrito w ith beans and rice.and don’t eat thechips!Another thing you can do is order a side salador a vegetable soup and eat it first.That way,you will eat some vegetables,and you won’t be able to eat as much of your burger and fries.Fnally,eat slowly and stop ea ting when you’re full. It sounds simple,but many people keep eating even after they become full.题目1 1.What is the main idea of this article________ 选择一项： A. It’s smart to eat foods with low calories and fat content. B. Fast food is always bad for you . C. You can eat well in fast-food restaurant D. Fast-food restaurants are the best the place to find healthy foods . 题目2 2.A small hamburger and small firies has __________ 选择一项： A. more calories and fat than a chicken sandwich and a salad. B. the same amount of calories and fat as a chicken sandwich and a salad. C. fewer calories andfat than a chicken sandwich and a salad. D. the same amount of calories and fat as a large portion of fries. 题目3 3.Some things you can do to eat well in fast-food restaurants are________ 选择一项： A. ask for eatra manyonnaise and sauce and say no to “surpersizing” . B. order a vegetable burrito instead of chips and eat sour cream . C. order smaller portions and eat all the food you order. D. order healthy foods instead of fatty ones and drink water.题目4 4.Manyonnaise and sauces probably_________ 选择一项： A. make you eat less because they make you feel full sooner. B. make you eat more because they make your food taste better. C. have a lot of fat and calories. D. don’t have a lot of fat and calories. 题目5 5. By eating a salad or soup before the rest of your meal,_______ 选择一项： A. you eat less of therest of your meal. B. you eat more slowly. C. you get full sooner. D. you eat the rest of your meal more quickly. II. Vocabulary skills（2 points） Read the paragraph below and fill in each blank with a wordfrom the box. (0.4 points each) 题目6 changesdamaging losing global available The growing similarities in diet and eating habits around the world are influencing people of various cultures in different ways. For example, Western foods are 6 damaging health in the industrialized island country of Japan. Instead of small meals of seafood, rice, and vegetables, the typical Japanese diet now includes large amounts of meat, dairy products, and desserts like tiramisu, a rich Italian dish full of chocolate, cheese, and sugar. According to Japanese health researchers, such 7 changes in eating habits are related to a great increase in health problems such as heart disease, strokes, cancer, and diabetes. On the other hand, the changing 8 global diet is having the opposite effect on the people in the CzechRepublic. The government of this European nation no longer supports meat and dairy products financially, so the cost of these foods is going up. In contrast, fresh fruits and vegetables are becoming more widely 9 available from private markets and stands. Cooks are even serving salads to schoolchildren, and familiesare eating healthier home-cooked meals. For these reasons, fewer Czech men are having heart attacks, the women are 10 losing a lot of weight, and most people are living healthier lives. Chapter 4 Exercise（分值7分 I. Vocabulary Skills（2 points）题目1 Match each vocabulary word on the left with the correctdefinition on the right. (0.4 points each) 1.make sense 2.pedestrians 3.vehicle 4.teenager 5.fine 答案：II. Reading Comprehension (5 points) Complete the following statements by choosing the best from the answers A, B, C, or D. (1 point each) These days,it’s getting easier and easie r to find your way around. Some people have GPS devices in their cars to make sure they don’t get lost. GPS stands for Global Positioning System. These devices use satellites in space to “see” where you are and give you directions to where you want to go. And if you don’t have a GPS device, you can simply go online to get step-by-step directions. Websites like and can produce a map and directions in just a few seconds. But how do they do it MapQuest®uses data (information) from a few different sources to produce directions and maps. Before MapQuest® went online, it sold regular paper maps in places like gas stations. The website uses the data from those paper maps, information from digital mapping companies, and government dat abases. At the moment, MapQuest® uses more than 30 computers to read all this data and provides users with millions of maps every day. In order to find the best route (way or path) from one place to another, MapQuest® first has to look at all possible rout es. Then MapQuest® looks at each part of each possible route. It considers the types of roads on the different routes. Are they dirt roads, paved roads, freeways, or city streets It looks at how many turns there are in each route and what kinds of turns they are. Are they right turns or left turns It also considers the speed limit on each road and how many intersections there are. An intersection is “a place where two or more roads cross each other”. MapQuest® can also tell you how long your trip will take you. It does this by doing some math. MapQuest® bases itsestimated driving times on the length and speed limit of each part of the route and the amount of time it probably takes to get through each intersection. For example, it allows more time for a left turn at an intersection than it does for a right turn. Someday, maybe we will have cars that can just drive us wherever we want to go, but for now, mapping websites make it a little harder to get lost. 题目2 6.What is the main idea of this article 选择一项： A. Why mapping websites don’t work well. B. Why mapping websites are better than paper maps. C. How mapping websites work. D. How the first mapping website started. 题目3 7.According to the article,MapQuest®______ 选择一项： A. started as maker of government databases. B. started as an Internet company. C. uses millions of computers to read data. D. starting by selling paper maps. 题目4 8.When you search for directions, the first thing MapQuest® does is_______ 选择一项： A. consider how many turns you want to take. B. print out a map and directions. C. estimate driving time. D. look at all possible paths.题目5 9.When it’s deciding on the best route, MapQuest® probably chooses ________ 选择一项： A. the route with the most turns. B. dirt roads instead of paved roads. C. freeways instead of dirt roads. D.city streets instead of freeways. 题目6 10. To estimate your driving time, MapQuest® considers_________ 选择一项： A. the distance between turns on your route. B. the speed limit for half of the route.C. the fastest and slowest speed limits on your route.D. the speed limits and types of turns on your route. Chapter 5 Exercise（分值7分） I. Reading Comprehension (5 points) Read the five main-idea questions that follow about the information in the reading. Three details correctly answer each question. Cross out the untrue, unrelated detail. (1 point each ) 题目1 1. What are the definitions of the two main types of families 选择一项： A. Human beings lived in loosely-related groups. Each group had a common ancestor long time ago. B. The nuclear family consists of two parents and their biological or adopted children. C. The extended family may includegrandparents, parents, children and relatives living together on the same street or in the same area. D. The nuclear family is the same as the extended family. 题目2 2. What are the reasons for the changes in the structure of the family 选择一项： A. The divorce rate went down and the birthrate began to rise in the early 1900s in the United States. B. Couples did not want many children then. C. In the early 1900s in the United States, the divorce rated went down and the birthrate went down. D. At that time, couples were staying married for few years. 题目3 3. What happened to families in industrialized countries in the 1930s and 1940s 选择一项： A. Before and during World War II, families faced few financial problems and women didn’t have to work away from home. B. Men were at war, so women had to work outside the home. C. Before and during World War II, families had problems. D. Families had serious financial problems during World War II. 题目4 4. What changes will happen to family structure during the next decades 选择一项： A. Divorces would be fewer, mothers would stay at homeafter the war. B. Children began living at home longer.C. After the war, family structure changed back.D.After the war, there were more divorces and fewerstay-home-mothers. 题目5 5. What will families belike in the future 选择一项： A. Many people want the traditional two-parent family back. B. Two-parentfamily will probably come back and all other family forms will end. C. Unmarried parents with adopted or foster children, and one-person households. D. There may be more single-parent families. II. VocabularySkills（2 points） Read the paragraph below and fillin each blank with a word from the box. ( 0.4 points each) 题目6 living extended category typical believe The Family of the Future Many people todaywould like the traditional two-parent family back—that is to say, they want a man and a woman to marryfor life; they also think the man should sport thefamily and the woman should stay home with thechildren. However, few families now fall into this 6 category In fact, if more women decide to havechildren on their own, the single-parent household maybecome more 7 typical than the traditional family in many countries. Also, unmarried couples may decided to have more children—or they might take in foster children or adopt. And because people are staying single and 8 living longer (often as widows), there may be more one-person households in the future. On the other hand, some people 9 believe similar events happen again and again in history. If this is true, people may go back to the traditional 10 extended or nuclear family of the past. Others think the only certainty in history is changing: in other words, the structure of the future family could begin to change faster and faster—and in more and more ways. Chapter 6 Exercise（分值7分） I. Vocabulary skills（2 points） Complete the following statements by choosing the best from the answers A, B, C, or D. （0.4 points each）题目1 1. Some examples of the architecture of old Europe are the magnificent cathedrals and castles. The design and building styles of modern architecture are excellent too. What does the noun architecture mean in these sentences 选择一项： A. the place withsignificant civilization everywhere B. people that study the culture of old Europe and other societies C. the art and science of designing the study ofclassical literature D. the form and plan of buildings and other structures 题目2 2. Perhaps the real beginning of civilization—with its scientific and technological discoveries and inventions—was in the Middle East and Africa. Over five thousand years ago, those ancient civilizations had astronomy, mathematics, medicine, government, and so on. Which word is a synonym of the word civilization 选择一项： A. technology B. cathedral C. culture D. astronomy 题目3 3. The cultural legacy of ancient Chinese and Indian peoples included walled cities, the first governments, tools for work, and weapons for protection. odern peoples built on this legacy.What is a possible explanation of the word legacy 选择一项： A. ideasand achievements passed from earlier generations to modern society B. a gift of money that somebody gives to another person C. international business conducted in cities and government structures D. the state orcondition of being legal; not against the law 题目 4 4. “For me, the idea of ancient culture creates a contradiction in definitions,” said Karen, going against Mei’s views. “On ly modern things can be part of culture.Of course, people that like classical art and music will contradict me.” What might the noun contradiction mean 选择一项： A. the opposition oftwo opinions B. wearing a Hawaiian shirt in an ancient culture C. the short forms of two words together D.to put words together 题目5 5. Because of the worldwide media—movies, TV, CDs, the Internet, newspapers, magazines—everybody knows the same information, plays the same music, and enjoys the same jokes.How might you define the phrase the media 选择一项： A. the combination of visual, sound, andprinted ways to send ideas around the world B. communication styles include motions, gestures and facial expressions C. the tradition of being in the middle—not on the extremes of possible views D.events that appear in the daily news and that everyone knows about II.Reading Comprehension (5 points) Decidewhether the following statements are true or false. Write “T” for True and “F” for False. （1 point each）题目6 Many visitors to different countries don’t realize how important it is to understand a country’s culture. Sometimes people learn this lesson by making a big cross-cultural blunder, or embarrassing mistake. In business situations, these blunders can cost a lot of money or end business relationships. 6.It is important to understand other people’s cultures before you do business with them. 选择一项： A. F B. T 题目7 For example, one company wanted to sell toothpaste in Southeast Asia. In their advertisements, they claimed that their toothpaste whitens teeth. They didn’t understand that many of the local people chewed betel nuts to make their teeth black, and that these people thought black teeth were attractive. 7. The toothpaste company probably kept using the same advertisement in Southeast Asia. 选择一项： A. F B. T 题目8 In another case, a car company tried to sell a car called “Matador” in a Spanish-speaking country. The company thought that itwas a strong name because it means “bullfighter”. In Spanish, matador is indeed a noun meaning “bullfighter”. But it is also an adjective meaning “killing”. Imagine driving around in a car called “Killing”! 8. The car company that tried to sell a car to a Spanish-speaking country probably didn’tsell many Matador cars in that country. 选择一项： A.F B. T 题目9 A European businessman had an important meeting with a company in Taiwan. He wanted to bring gifts for the people he was meeting with. He thought that something with his company’s logo on it would be a nice gift. So he bought some very nice pocket knives and had his company’s logo printed on them. Hedidn’t know that giving a knife as a gift symbolizes cutting off a friendship! 9. The European businessman probably researches new cultures before he visits them now. 选择一项： A. T B. F 题目10 It’s very easy to make blunders like these people did. But it’s also very easy not to. Before you visit a new country, research that country’s customs and etiquette (social rules for polite behavior). You can find a lot ofinformation online. Just go to a search engine and type in key words like “cross-cultural etiquette” or “cultural information Taiwan”. By spending a few minutes doing research, you can save yourself from a lot of embarrassment and make sure you don’t accidentally offend anyone. 10. What you can disagree with people to save yourself from making cross-cultural blunders. 选择一项： A. T B. F Chapter 7 Exercise（分值7分） I. Reading Comprehension (5 points) Decide whether the following statements are true or false. Write “T” for True and “F” for False on the Answer Sheet. (1 point each) 题目1 For instance, a doctor doesn’t always have time to thoroughly explain an illness. In these cases, the Internet can be a valuable resource—a place to read all about the causes, symptoms, and remedies for an illness. 1. One benefit of using the Internet as a medical resource is it has a lot of information about illnesses and diseases. 选择一项： A. F B. T 题目2 For example, some websites claim that sniffing (smelling) a newspaper can cure nausea (the feeling ofbeing sick to your stomach and wanting to vomit). 2. One possible remedy for nausea is drinking a lot of tea. 选择一项： A. T B. F 题目3 Other websites suggest that a person with a cold should keep a piece of raw garlic in his or her mouth all day and bite down on it every few minutes to release the juice. People with smelly feet are told to soak their feet in tea for half an hour. 3. The websites remedies might be unpleasant or odd, but they probably will cause harm. And who knows They might actually be unhelpful. 选择一项： A. F B. T 题目4 An herbal remedy for helping your memory may also be a blood thinner. So if your doctor prescribed (put you on) a blood thinnerand you start taking this herb without asking your doctor about it, a simple cut could be deadly; you might not be able to stop bleeding. 4. A person whois taking a prescribed drug should probably talk tothe doctor before taking an herbal remedy. 选择一项：A. F B. T 题目5 The bottom line is this: be careful when using the Internet as a health resource. Use itto find information that you can discuss with yourdoctor. But don’t spend a lot of money on “miracle cures”. 5. The best way to use the Internet as a medical resource is to read about your illness and discuss what you find out with your doctor. 选择一项： A. T B. F II. Vocabulary skills（2 points） Read the paragraph below and fill in each blank with a word from the box. ( 0.4 points each) 题目6 disease substance classification prevent figure In a small-town farm market, hundreds of elderly people drink a glass of sour dark cherry juice every day. These happy senior citizens, some of them over the age of 90, claim that the natural fruit juice cures—or at least decreases—the pain of their arthritis, a 6 disease of the joints of the aging body. It’s a folk remedy, not a proven medical therapy. Nevertheless, science is beginning to 7 figure out why sour cherry juice might work to improve the health of patients with arthritis. The secret is in the 8 substance that gives the cherries their dark red color. It belongs to a 9 classification of natural nutrients that color blueberries, strawberries, plums, and other fruits—。
最新国家开放大学电大《电气传动与调速系统》网络课选择题答案
最新国家开放大学电大《电气传动与调速系统》网络课选择题答案最新国家开放大学电大《电气传动与调速系统》网络课选择题答案选择题题目1电气传动系统做旋转运动时，其运动方程为（）。
选择一项：题目2如图所示的旋转运动系统（箭头方向表示转矩的实际方向），系统的运动状态是（）。
选择一项：A.匀速B.加速C.静止D.减速题目3如图所示的负载机械特性属于（）。
选择一项：A.恒功率负载机械特性B.位能性恒转矩负载机械特性C.反抗性恒转矩负载机械特性D.直线型负载机械特性题目4如图所示的电动机机械特性（曲线1）与负载机械特性（曲线2）相交的交点分别为A和B，以下说法正确的是（）。
选择一项：A.A点是稳定运行点，B点是稳定运行点B.A点是稳定运行点，B点不是稳定运行点C.A点不是稳定运行点，B点不是稳定运行点D.A点不是稳定运行点，B点是稳定运行点题目5直流电动机的换向器与电刷配合，可将电枢绕组内的（）变换为电刷上的直流电势。
选择一项：A.交流电势B.直流电势C.恒定电压D.不变电势题目6如图所示为他励直流电动机的机械特性曲线组，表示的是（）的人为机械特性。
选择一项：A.减弱磁通B.降低电源电压C.电枢回路串电阻D.增大磁通题目7如图所示为他励直流电动机的工作特性曲线，下述表达正确的是（）。
选择一项：A.曲线1是转速特性，曲线2是效率特性，曲线3是转矩特性B.曲线1是转矩特性，曲线2是效率特性，曲线3是转速特性C.曲线1是效率特性，曲线2是转速特性，曲线3是转矩特性D.曲线1是转速特性，曲线2是转矩特性，曲线3是效率特性题目8如图所示他励直流电动机机械特性与负载机械特性曲线的交点a,b,c,d，下述表达正确的是（）。
选择一项：A.从a点到b点是属于调速运行，从c点到d点属于调速运行B.从a点到c点是属于调速运行，从c点到d点属于调速运行C.从a点到c点是属于调速运行，从b点到d点属于调速运行D.从a点到b点是属于调速运行，从b点到d点属于调速运行题目9三相异步电动机正常运行时，转子转速为n，定子旋转磁场的转速为ns，则该电动机的转差率s为（）。
电气传动与调速系统形成性考核作业2
电气传动与调速系统形成性考核作业2（含答案）一、选择题（每小题5分，共40分）题目1三相异步电动机正常运行时，转子转速为n，定子旋转磁场的转速为ns，则该电动机的转差率s为（）。
选择一项：A.B.C.D.反馈正确答案是：题目2一台6极三相异步电动机，定子电流频率为60Hz，电机正常运行时，定子旋转磁场的转速为（）。
选择一项：A. 1000r/minB. 1200r/minC. 600r/minD. 500r/min反馈正确答案是：1200r/min题目3一台8极三相异步电动机，定子电流频率为50Hz，电机正常运行时的转差率s为0.04，则该电机正常运行时转子电流的频率为（）。
选择一项：A. 1.5 HzB. 50 HzC. 48 HzD. 2 Hz反馈正确答案是：2 Hz题目4三相异步电动机的T型等效电路如图所示，m1表示电机的相数，则定子绕组的铜耗可表示为（）。
选择一项：A.B.C.D.反馈正确答案是：题目5三相异步电动机的固有机械特性如图所示，则A点是（）。
选择一项：A. 起动点B. 最大转矩点C. 额定运行点D. 同步转速点反馈正确答案是：同步转速点题目6三相异步电动机的人为机械特性如图所示，该图表示的是（）的人为机械特性。
选择一项：A. 转子回路串电阻B. 降低电源电压C. 改变频率（基频以下）D. 改变频率（基频以上）反馈正确答案是：降低电源电压题目7一台同步电动机的矩角特性如图所示，可知，该同步电动机为（）。
选择一项：A. 凸极同步电动机B. 隐极同步电动机C. 笼型同步电动机D. 绕线式同步电动机反馈正确答案是：隐极同步电动机题目8为了调节同步电动机从电网吸取的无功功率以及同步电动机的功率因数，需要调节同步电动机的（）就可以实现。
选择一项：A. 负载的功率因数B. 电枢电压C. 励磁电流D. 电枢电流反馈正确答案是：励磁电流二、判断题（每小题5分，共40分）题目9三相异步电动机的转子绕组分为笼型转子和绕线型转子两类。
国家开放大学 电气传动与调速系统章节测试参考答案
《电气传动与调速系统》章节测试参考答案第一章电气传动的动力学基础1-1 电气传动系统的运动方程、多轴系统和机械特性一、单选题1.电气传动系统中，除了电源和生产机械外，还有（）A. 发动机、传动机构和控制设备B. 电动机、传动机构和控制设备C. 电动机、传动机构和显示设备D. 电动机、传动机构和显示设备2.动态转矩时，系统处于（）A. 加速运动的过渡状态B. 恒转速稳定状态C. 静止状态D. 减速运动的过渡状态3.电动机为发电状态时，传送到电机的功率（）工作机构轴上的功率A. 小于B. 等于C. 均有可能D. 大于4.在电动机转子、工作机构和传动机构中，飞轮矩所占比重最大的是（）A. 均有可能B. 传动机构C. 工作机构D. 电动机转子5.对于反抗性恒转矩负载，n为正方向时TL为正值，n为负方向时TL也为负值，所以反抗性恒转矩负载特性曲线应在（）内A. 第二和第四象限B. 第二和第三象限C. 第一和第二象限D. 第一和第三象限6.图示机械特性曲线中，（C）是恒功率负载特性。
A. B.C. D.二、判断题7.由电气传动系统作旋转运动时的运动方程可知，T与TL都是有方向的变量，电磁转矩T的正方向与n相同，负载转矩TL的正方向与n相反。
（√）8.将多轴系统折算为一个等效的单轴系统后，折算前后系统传递的功率及系统所存储的动能不变。
（√）9.电动机带动工作机构旋转时，传动损耗由工作机构负担。
（×）10.下放重物时，重物在重力作用下拉着整个系统反向运动，电动机的电磁转矩是制动转矩，传动机构的损耗由电动机承担。
（×）11.起重机的重物升降运动中，重物不论是做提升还是下放运动，重物的重力所产生的负载转矩的方向总是不变的。
（√）12.泵类负载的生产机械中，介质对机器叶片的阻力与转速成正比关系。
（×）1-2 电气传动系统稳定运行条件一、单选题1.电气传动系统稳定运行的必要条件是，电动机的机械特性曲线与负载的机械特性曲线（）A. 要经过原点B. 一定要有交点C. 要在第一象限D. 一定不能有交点2.恒转矩负载稳定运行的充分条件为（）。
[国家开放大学电大《C语言程序设计》《电气传动与调速系统》络课形考考作业(合集)答案]
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[GJ开放大学电大《C语言程序设计》《电气传动与调速系统》络课形考考作业(合集)答案] GJ开放大学电大《C语言程序设计》《电气传动与调速系统》XX络课形考XX考作业(合集)答案《C语言程序设计》XX络课答案形考任务1 一、选择题〔共40分，每题2分〕题目1 在每个C语言程序中都必需包含有这样一个函数，该函数的函数名为〔〕。
选择一项：. min 恭喜你，答对啦！！B. MIN C. nme D. function 题目2 C 语言源程序文件的缺省扩展名为〔〕。
选择一项：. cpp B. exe C. obj D. c 题目3 由C语言目标文件连接而成的可执行文件的缺省扩展名为〔〕。
选择一项：. cpp B. exe C. obj D. c 题目4 程序运行中需要从键盘上输入多于一个数据时，各数据之间应使用的分隔符为〔〕。
选择一项：. 空格或逗号B. 逗号或回车C. 逗号或分号D. 空格或回车题目5 每个C语言程序文件的编译错误被分为〔〕。
选择一项：. 1类B. 2类 C. 3类D. 4类题目6 不符合C语言规定的复合语句是〔〕。
选择一项：. {} B. {;} C. {x=0;} D. {y=10} 题目7 C语言程序中的基本功能模块为〔〕。
选择一项：. 表达式B. 标识符C. 语句D. 函数题目8 在一个函数定义中，函数头包括的3个部分依次为函数类型、函数名和〔〕。
选择一项：. 表达式B. 语句C. 参数表 D. 函数体题目9 在一个程序文件中，若要使用在C语言程序中，多行注释语句使用的开始标记符为〔〕。
选择一项：. // B. /* C. */ D. ** 题目11 在printf()函数调用的格式字符串中，若使用格式符为“%c〞，则对应输出的数据类型为〔〕。
选择一项：. chr B. int C. flot D. double 题目12 在printf()函数调用的格式字符串中，若使用格式符为“%5d〞，则规定对应输出的数据占用的字符位置个数为〔〕。
国家开放大学《电气传动与调速系统》第1次形成性考核作业试题
国家开放大学《电气传动与调速系统》第1次形成性考核作业试题题目1：电气传动系统做旋转运动时，其运动方程为（）。
题目2：如图所示的旋转运动系统（箭头方向表示转矩的实际方向），系统的运动状态是（）。
: 匀速; 加速; 静止; 减速题目3：如图所示的负载机械特性属于（）。
: 直线型负载机械特性; 反抗性恒转矩负载机械特性; 位能性恒转矩负载机械特性; 恒功率负载机械特性题目4：如图所示的电动机机械特性（曲线1）与负载机械特性（曲线2）相交的交点分别为A和B，以下说法正确的是（）。
: A点不是稳定运行点，B点不是稳定运行点; A点是稳定运行点，B点不是稳定运行点; A点是稳定运行点，B点是稳定运行点; A点不是稳定运行点，B点是稳定运行点题目5：直流电动机的换向器与电刷配合，可将电枢绕组内的（）变换为电刷上的直流电势。
: 直流电势; 交流电势; 不变电势; 恒定电压题目6：如图所示为他励直流电动机的机械特性曲线组，表示的是（）的人为机械特性。
: 降低电源电压; 电枢回路串电阻; 减弱磁通; 增大磁通题目7：如图所示为他励直流电动机的工作特性曲线，下述表达正确的是（）。
: 曲线1是效率特性，曲线2是转速特性，曲线3是转矩特性; 曲线1是转速特性，曲线2是转矩特性，曲线3是效率特性; 曲线1是转矩特性，曲线2是效率特性，曲线3是转速特性; 曲线1是转速特性，曲线2是效率特性，曲线3是转矩特性题目8：如图所示他励直流电动机机械特性与负载机械特性曲线的交点a,b,c,d，下述表达正确的是（）。
: 从a点到c点是属于调速运行，从b点到d点属于调速运行; 从a点到b点是属于调速运行，从b点到d点属于调速运行; 从a点到b点是属于调速运行，从c点到d点属于调速运行; 从a点到c点是属于调速运行，从c点到d点属于调速运行题目9：当传动系统做旋转运动时，作用在电动机轴上的电磁转矩_T_和负载转矩_TL_之差，即_T_-_TL_=△_T_称为动态转矩，当△_T_>0，即d_n_/dt > 0时，系统处于加速运行状态。
国家开放大学电大《文论专题》《电气传动与调速系统》网络课形考网考作业(合集)答案
国家开放大学电大《文论专题》《电气传动与调速系统》网络课形考网考作业(合集)答案《文论专题》网络课答案形考任务1题目1著名的改良派人士梁启超提出文艺的四种社会作用即：薰、浸、刺、提。
所谓“刺”，指的是文艺作品培养接受者审美接受能力的作用。
选择一项：对错题目2孔子所说的“兴”的含义，就是通过艺术形象的譬喻，引发人的联想，并进而使人领会到某种类似的，深微曲隐的思想感情，从而在精神上受到感染和熏陶。
选择一项：对错题目3孔子的思想，可以说是以“仁”为内容，以“礼”为形式，以“中庸”为准则，所以也被称为“仁学”。
选择一项：对错题目4“兴观群怨”的发展过程中存在着这样一种共同规律，就是在孔子那里主要是针对“用诗”，即发挥文艺社会作用而提出的“兴观群怨”，在后世都逐渐与“作诗”结合起来，使“兴观群怨”不仅成为对文艺社会作用的一种自觉认识，而且成为对文艺创作的一种明确要求。
选择一项：对错题目5孔子的思想主要保存在《论语》中。
选择一项：对错题目6庄子的“言不尽意”说对后世的影响深远而巨大，北宋欧阳修的就是例证。
选择一项：A. 思表纤旨，文外曲致，言所不追B. 言有尽而意无穷C. “状难写之景，如在目前；含不尽之意，见于言外"D. 文已尽而意有余题目7通过艺术形象的譬喻，引发人的联想，并进而使人领会到某种类似的，深微曲隐的思想感情，从而在精神上受到感染和熏陶，这是。
选择一项：A. 兴B. 怨C. 群D. 观题目8明末清初的王夫之特别重视文艺的审美情感特征，他将“兴观群怨”称之为“”选择一项：A. 四情B. 四义C. 四教D. 四学题目9孔子的文艺观是他的“”思想在文艺方面的鲜明体现。
选择一项：A. 礼学B. 义学C. 诗学D. 仁学题目10“兴观群怨”说是孔子“”文艺观的代表。
选择一项：A. 诗教B. 礼教C. 德教D. 仁教题目11怎样理解庄子的得意忘言?答：《庄子·外物》：“蹄者所以在兔，得兔而忘蹄。
国家开放大学电大《C语言程序设计》《电气传动与调速系统》网络课形考网考作业(合集)答案
国家开放大学电大《C语言程序设计》《电气传动与调速系统》网络课形考网考作业(合集)答案国家开放大学电大《C语言程序设计》《电气传动与调速系统》网络课形考网考作业(合集)答案《C语言程序设计》网络课答案形考任务1 一、选择题（共40分，每小题2分）题目1 在每个C语言程序中都必须包含有这样一个函数，该函数的函数名为（）。
选择一项： A. main 恭喜你，答对啦！！ B. MAIN C. name D. function 题目2 C语言源程序文件的缺省扩展名为（）。
选择一项： A. cpp B. exe C. obj D. c 题目3 由C 语言目标文件连接而成的可执行文件的缺省扩展名为（）。
选择一项： A. cpp B. exe C. obj D. c 题目4 程序运行中需要从键盘上输入多于一个数据时，各数据之间应使用的分隔符为（）。
选择一项： A. 空格或逗号 B. 逗号或回车 C. 逗号或分号 D. 空格或回车题目5 每个C语言程序文件的编译错误被分为（）。
选择一项： A. 1类 B. 2类 C. 3类 D. 4类题目6 不符合C语言规定的复合语句是（）。
选择一项： A. {} B. {;} C. {x=0;} D. {y=10} 题目7 C语言程序中的基本功能模块为（）。
选择一项： A. 表达式 B. 标识符 C. 语句 D. 函数题目8 在一个函数定义中，函数头包括的3个部分依次为函数类型、函数名和（）。
选择一项： A. 表达式 B. 语句 C. 参数表 D. 函数体题目9 在一个程序文件中，若要使用#include命令包含一个用户定义的头文件，则此头文件所使用的起止定界符为一对（）。
选择一项： A. 尖括号 B. 双引号 C. 单引号 D. 花括号题目10 在C语言程序中，多行注释语句使用的开始标记符为（）。
选择一项： A. // B. /* C. */ D. ** 题目11 在printf()函数调用的格式字符串中，若使用格式符为“%c”，则对应输出的数据类型为（）。
最新国家开放大学电大《电气传动与调速系统》网络课选择题答案
《最新国家开放大学电大《电气传动与调速系统》网络课选择题答案》摘要：起动题目三相异步电动机人机械特性如图所示该图表示是（）人机械特性，磁场控制电阻控制题目9 台伺电动机机械特性曲线如图所示可知该电动机应该是（），输出侧滤波电容续流二极管储能电感题目7 保证（）异步电动机变频调速程电磁矩维持不变新国开放学电《电气传动与调速系统》络课选择题答案选择题题目电气传动系统做旋运动其运动方程（）选择项题目如图所示旋运动系统（箭头方向表示矩实际方向）系统运动状态是（）选择项匀速 B 加速静止减速题目3 如图所示机械特性属（）选择项恒功率机械特性 B 位能性恒矩机械特性反抗性恒矩机械特性直线型机械特性题目如图所示电动机机械特性（曲线）与机械特性（曲线）相交交分别和B以下说法正确是（）选择项是稳定运行B是稳定运行 B 是稳定运行B不是稳定运行不是稳定运行B不是稳定运行不是稳定运行B是稳定运行题目5 直流电动机换向器与电刷配合可将电枢绕组（）变换电刷上直流电势选择项交流电势 B 直流电势恒定电压不变电势题目6 如图所示他励直流电动机机械特性曲线组表示是（）人机械特性选择项减弱磁通 B 降低电电压电枢回路串电阻增磁通题目7 如图所示他励直流电动机工作特性曲线下述表达正确是（）选择项曲线是速特性曲线是效率特性曲线3是矩特性 B 曲线是矩特性曲线是效率特性曲线3是速特性曲线是效率特性曲线是速特性曲线3是矩特性曲线是速特性曲线是矩特性曲线3是效率特性题目8 如图所示他励直流电动机机械特性与机械特性曲线交,b,,下述表达正确是（）选择项从到b是属调速运行从到属调速运行 B 从到是属调速运行从到属调速运行从到是属调速运行从b到属调速运行从到b是属调速运行从b到属调速运行题目9 三相异步电动机正常运行子速定子旋磁场速则该电动机差率（）选择项题目0 台6极三相异步电动机定子电流频率60z电机正常运行定子旋磁场速（）选择项 000r B 00r 600r 500r 题目台8极三相异步电动机定子电流频率50z电机正常运行差率00则该电机正常运行子电流频率（）选择项 8 z B 50 z 5 z z 题目三相异步电动机型等效电路如图所示表示电机相数则定子绕组铜耗可表示（）选择项题目3 三相异步电动机固有机械特性如图所示则是（）选择项步速 B 额定运行矩起动题目三相异步电动机人机械特性如图所示该图表示是（）人机械特性选择项改变频率（基频以下） B 降低电电压子回路串电阻改变频率（基频以上）题目5 台步电动机矩角特性如图所示可知该步电动机（）选择项凸极步电动机 B 隐极步电动机笼型步电动机绕线式步电动机题目6 了调节步电动机从电吸取无功功率以及步电动机功率因数要调节步电动机（）就可以实现选择项功率因数 B 电枢电流励磁电流电枢电压题目7 微型步电动机根据子结构型式和所用材不主要分永磁式微型步电动机、反应式微型步电动机和（）选择项隐极微型步电动机 B 磁滞式微型步电动机鼠笼式微型步电动机绕线式微型步电动机题目8 直流伺电动机控制方式有电枢控制和（）选择项电流控制 B 电压控制磁场控制电阻控制题目9 台伺电动机机械特性曲线如图所示可知该电动机应该是（）选择项笼型伺电动机 B 直流伺电动机永磁伺电动机交流伺电动机题目0 台伺电动机机械特性曲线如图所示可知该电动机应该是（）选择项直流伺电动机 B 永磁伺电动机笼型伺电动机交流伺电动机题目步进电动机也称（）是种将输人脉冲信换成输出轴角位移（或直线位移）执行元件选择项永磁电动机 B 交流电动机直流电动机脉冲电动机题目电动机某部位温θ与电动机周围介质温θ0差称电动机该部位（）用τ表示即τ θθ0选择项温升限值 B 温升温升温升题目3 我国国标准《旋电机定额和性能》（GB755008）规定周围冷却空气高温（）选择项题目电动机（）选择首先必须校验电动机运行温升特别当传动系统是变化或者是冲击性还必须根据温升校核再核验电动机能力或起动能力等选择项额定功率 B 额定电压起动电流倍数额定速题目5 晶闸管触发导通通以下哪种方式可以让其关断？（）选择项门极不加电流 B 阳极与阴极加正压门极加电流阳极与阴极加反压题目6 升压变换器开关管导通能量由以下哪种元件提供？（）选择项输入电 B 输出侧滤波电容续流二极管储能电感题目7 保证（）异步电动机变频调速程电磁矩维持不变选择项恒定端电压频率 B 恒定电动势恒定电动势频率恒定端电压题目8 电压型通用变频器直流侧采用（）对整流电压进行滤波选择项二极管 B 晶闸管电感电容题目9 变频调速系统出现与机械系统固有频率发生谐振要设置（）选择项频率跳变 B 下限频率起动频率上限频率题目30 异步电动机变频调速减速设置短会导致（）选择项直流侧欠电压 B 输入侧欠电压直流侧电压输入侧电压题目3 恒压变频供水系统变频器不要设置（）选择项动频率 B 减速高频率升速题目3 台变频器驱动多台步电动机进行变频调速应采用（）选择项交直交无换向器电动机调速系统 B 反电势换流型无换向器电动机调速系统他控式变频调速系统交交无换向器电动机调速系统。
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国开电大专科《电气传动与调速系统》网上形考任务试题及答案国开电大专科《电气传动与调速系统》网上形考任务试题及答案说明.资料于2021年11月27日。
第1次形成性考核作业试题及答案题目1：电气传动系统做旋转运动时，其运动方程为( )。
[答案] 题目2：如下列图的旋转运动系统(箭头方向表示转矩的实际方向)，系统的运动状态是( )。
[答案]减速题目3：如下列图的负载机械特性属于( )。
[答案]对抗性恒转矩负载机械特性题目4：如下列图的电动机机械特性(曲线1)与负载机械特性(曲线2)相交的交点分别为A和B，以下说法正确的选项是( )。
[答案]A点是稳定运行点，B点是稳定运行点题目5：直流电动机的换向器与电刷配合，可将电枢绕组内的( )变换为电刷上的直流电势。
[答案]交流电势题目6：如下列图为他励直流电动机的机械特性曲线组，表示的是( )的人为机械特性。
[答案]电枢回路串电阻题目7：如下列图为他励直流电动机的工作特性曲线，下述表达正确的选项是( )。
[答案]曲线1是转速特性，曲线2是效率特性，曲线3是转矩特性题目8：如下列图他励直流电动机机械特性与负载机械特性曲线的交点a,b,c,d，下述表达正确的选项是( )。
[答案]从a点到c点是属于调速运行，从b点到d点属于调速运行题目9：当传动系统做旋转运动时，作用在电动机轴上的电磁转矩T和负载转矩TL之差，即T-TL=△T称为动态转矩，当△T>0，即dn/dt > 0时，系统处于加速运行状态。
[答案]对题目10：如下列图的负载机械特性属于恒功率负载机械特性。
[答案]错题目11：如下列图的电动机机械特性(曲线1)与负载机械特性(曲线2)相交的交点分别为C、D和E，那么C点不是稳定运行点，D点是不稳定运行点, E点是稳定运行点。
[答案]错题目12：直流电机的主磁极是产生电动势的部件。
[答案]错题目13：直流电动机工作时，其电枢绕组中的电流是交流电流。
[答案]对题目14：直流电动机的转速大小与励磁电流大小、电枢回路电阻值和所加电源电压的极性有关。
[答案]错题目15：如下列图为他励直流电动机的机械特性曲线组，表示的是电枢回路串电阻的人为机械特性。
[答案]错题目16：如下列图为他励直流电动机四象限运行的机械特性曲线，曲线1是正向电动运行状态，曲线2是能耗制动运行状态，曲线3是反向电动运行状态。
[答案]对题目17：切削时折算到电动机轴上的负载转矩为( )。
[答案]41.2Nm 题目18：取，估算系统的总飞轮矩为( )。
[答案]130Nm2 题目19：电动机的理想空载转速为( )。
[答案]1694r/min 题目20：电动机的额定电磁转矩为( )。
[答案]206.8Nm 第2次形成性考核作业试题及答案题目1：三相异步电动机正常运行时，转子转速为n，定子旋转磁场的转速为ns，那么该电动机的转差率s为( )。
[答案] 题目2：一台6极三相异步电动机，定子电流频率为60Hz，电机正常运行时，定子旋转磁场的转速为( )。
[答案]1200r/min 题目3：一台8极三相异步电动机，定子电流频率为50Hz，电机正常运行时的转差率s为0.04，那么该电机正常运行时转子电流的频率为( )。
[答案]2 Hz 题目4：三相异步电动机的T型等效电路如下列图，m1表示电机的相数，那么定子绕组的铜耗可表示为( )。
[答案] 题目5：三相异步电动机的固有机械特性如下列图，那么A 点是( )。
[答案]同步转速点题目6：三相异步电动机的人为机械特性如下列图，该图表示的是( )的人为机械特性。
[答案]降低电源电压题目7：一台同步电动机的矩角特性如下列图，可知，该同步电动机为( )。
[答案]隐极同步电动机题目8：为了调节同步电动机从电网吸取的无功功率以及同步电动机的功率因数，需要调节同步电动机的( )就可以实现。
[答案]励磁电流题目9：三相异步电动机的转子绕组分为笼型转子和绕线型转子两类。
[答案]对题目10：一台4极三相异步电动机，定子电流频率为50Hz，电机正常运行时的转差率s为0.02，那么该电机定子旋转磁场与转子之间的相对转速为30r/min。
[答案]对题目11：三相异步电动机的人为机械特性如下列图，该图表示的是降低电源电压的人为机械特性。
[答案]错题目12：三相异步电动机能耗制动时的机械特性不经过原点，但位于第二、四象限内。
[答案]错题目13：三相异步电动机的调速方法有：变极调速、变频调速和弱磁调速。
[答案]错题目14：隐极同步电动机的定子电压方程为。
[答案]错题目15：凸极同步电动机的电磁转矩与功率角之间的关系(矩角特性)可表示为。
[答案]对题目16：当同步电动机的励磁电流大于正常励磁值时，同步电动机处于过励运行状态。
[答案]对题目17：电动机的同步转速和额定转差率分别为( )。
[答案]1000r/min，0.035 题目18：电动机定子绕组的额定相电压与转子电流的频率分别为( )。
[答案]220V，1.75Hz 题目19：电动机的额定转差率和定子绕组的额定相电压分别为( )。
[答案]0.035，220V 题目20：电动机的额定电磁转矩和起动转矩分别为( )。
[答案]35Nm，31.2Nm 第3次形成性考核作业试题及答案题目1：微型同步电动机根据转子结构型式和所用材料不同主要分为永磁式微型同步电动机、反响式微型同步电动机和( )。
[答案]磁滞式微型同步电动机题目2：直流伺服电动机的控制方式有：电枢控制和( )。
[答案]磁场控制题目3：一台伺服电动机的机械特性曲线如下列图，可知，该电动机应该是( )。
[答案]直流伺服电动机题目4：一台伺服电动机的机械特性曲线如下列图，可知，该电动机应该是( )。
[答案]交流伺服电动机题目5：步进电动机也称( )，是一种将输人脉冲信号转换成输出轴的角位移(或直线位移)的执行元件。
[答案]脉冲电动机题目6：电动机某部位的温度θ与电动机周围介质的温度θ0之差，称为电动机该部位的( )，用τ表示，即τ =θ-θ0。
[答案]温升题目7：我国国家标准《旋转电机定额和性能》(GB755-xx)中规定周围冷却空气的最高温度为( )。
[答案] 题目8：电动机( )的选择，首先必须校验电动机运行时的温升，特别当传动系统中的负载是变化的，或者是冲击性负载时，还必须根据温升校核后再核验电动机的过载能力或起动能力等。
[答案]额定功率题目9：反响式微型同步电动机转子在不同的方向具有不同的磁阻，X轴方向磁阻最小，交轴方向磁阻最大。
[答案]错题目10：根据自动控制系统的要求，伺服电动机必须具备可控性好、稳定性高和响应快速等根本性能。
[答案]对题目11：交流伺服电动机的控制方式有：幅值控制、相位控制和电流控制。
[答案]错题目12：在电机内部，当发热量等于散热量时，电机温升不再升高，逐步到达其稳定温升τw。
[答案]对题目13：电机在发热过程中的温升曲线与在冷却过程中的冷却曲线均是按指数规律变化的，变化的快慢与发热时间常数T 有关，同一物体的冷却时间常数与发热时间常数T的关系是相同的。
[答案]对题目14：电机中常用的绝缘材料按其耐热能力可分为A、E、B、F、H、C、N和R八个等级，相应绝缘等级最高温度分别为105、120、130、155、180、200、220、240(℃)。
[答案]对题目15：我国国家标准《旋转电机定额和性能》(GB755-xx)中，将电动机的工作方式分为连续工作制、断续周期工作制和长时工作制。
[答案]错题目16：在电动机的断续周期工作制中，我国国家标准《旋转电机定额和性能》(GB755-xx)规定的负载持续率有15%、25%、40% 和60%四种，相应还规定每个工作和停机的周期不大于10min。
[答案]对题目17：电机作三相单三拍运行时，电机的齿距角与步距角分别为( )。
[答案]30o，10o 题目18：电机作三相双六拍运行时，电机的齿距角与步距角分别为( )。
[答案]30o，5o 题目19：当电机的步距角为1.2°时，转子的齿数Z为( )。
[答案]50 题目20：电机转子每分钟的转速为( )。
[答案]160r/min 第4次形成性考核作业试题及答案题目1：晶闸管在触发导通之后，通过以下哪种方式可以让其关断？( ) [答案]阳极与阴极间加反压题目2：升压DC/DC变换器在开关管导通时，负载能量由以下哪种元件提供？( ) [答案]输出侧滤波电容题目3：保证( )时，异步电动机在变频调速过程中最大电磁转矩维持不变。
[答案]恒定的电动势/频率题目4：电压源型通用变频器在直流侧采用( )对整流后的电压进行滤波。
[答案]电容题目5：变频调速系统出现与机械系统的固有频率发生谐振时，需要设置( )。
[答案]频率跳变题目6：异步电动机变频调速时，减速时间设置过短会导致( )。
[答案]直流侧过电压题目7：恒压变频供水系统中，变频器不需要设置( )。
[答案]点动频率题目8：一台变频器驱动多台同步电动机进行变频调速时，应采用( )。
[答案]他控式变频调速系统题目9：单相桥式全控整流电路在触发角不为零时，带反电势负载的直流侧电压比带电阻负载的直流侧电压低。
[答案]错题目10：IGBT器件的开通速度比晶闸管器件的开通速度快。
[答案]对题目11：降压型DC/DC变换器的输出电压与占空比成正比。
[答案]对题目12：异步电动机变频调速时，低速时通常需要在恒端电压/频率的根底上适当减小定子电压来补偿定子电阻压降的影响。
[答案]错题目13：规那么采样法实现SPWM时，采用载波正峰值采样的方法更准确。
[答案]错题目14：旋转变压器只能测量速度大小，无法输出转轴的绝对位置信息。
[答案]错题目15：无换向器电动机调速系统在高速运行时通常采用电流断续法进行换流。
[答案]错题目16：交-交无换向器电动机调速系统在低速运行时通常采用电源换流的方法进行换流。
[答案]对题目17：在起动过程中，如果速度调节器处于饱和限幅状态，此时系统表现为( )调节特性。
[答案]恒电流题目18：起动过程结束后，电动机的转速与设定转速的关系为( )。
[答案]电动机的转速等于设定转速题目19：无换向器电动机的速度调节主要通过控制( )实现。
[答案]整流侧触发角α 题目20：无换向器电动机高速运行在第三象限电动状态时，对应的整流侧触发角和换流超前角分别是( )。
[答案]α<90°, γ0=180°。