【单选题】【消耗次数:1】
旋转磁场由三相电流通过三相对称绕组产生。
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错误
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相关题目
【单选题】 对称()绕组外加对称三相交流电压,定子绕组内有对称三相交流电流,它们联合产生旋转磁场。
①  转子
②  定子
【判断题】 三相对称绕组极对数及有效匝数一定,当接三相对称电源后产生的基波旋转磁势幅值?大小由三相电流的大小决定
①  正确
②  错误
【判断题】 三相对称绕组极对数及有效匝数一定,当接三相对称电源后其转向由三相电流的频率决定。
①  正确
②  错误
【单选题】 三相感应电机通以三相对称电流,若一相绕组断线(绕组无中线),将产生()。
①  圆形旋转磁场;
②  脉振磁场;
③  椭圆形旋转磁场。
【判断题】 三相异步电机中转子绕组产生旋转磁场。
①  正确
②  错误
【单选题】 三相异步电动机的旋转方向与通入三相绕组的三相电流( )有关。
①  大小
②  方向
③  相序
④  频率
【判断题】 三相对称电流电加在三相异步电动机的定子端,将会产生旋转圆形磁场。
①  正确
②  错误
【单选题】 三相对称交流绕组通入三相对称交流电流产生的合成基波磁动势为( )。
①  圆形旋转磁动势
②  椭圆型旋转磁动势
③  脉振磁动势
【单选题】 三相异步电机中产生旋转磁场的是( )。
①  转子绕组
②  定子绕组
③  铁芯
④  气隙
【单选题】 三相对称电路是指( )。
①  三相电源对称的电路
②  三相负载对称的电路
③  三相电源和三相负载均对称的电路
随机题目
【单选题】 Which type does the following production practice belong to? The students repeat what the teacher says. This activity can practice individual sounds, individual words, groups of words, and sentences.
①  Listen and repeat
②  Fill in the blanks
③  Make up sentences
④  Using meaningful context
【单选题】 What does the falling intonation on the question “where do you live ?” indicate?
①  I am telling you something you do not know
②  I have not finished yet
③  I am asking a genuine question
④  I know you have told me before.
【单选题】 What is reflected as important in the following example? A. Would you please turn down the radio a little bit? B. Sorry. ↘ (no, I do not want to.) Or B. Sorry? ↗ (what did you say?)
①  Stress
②  Intonation
③  Sounds
④  Pitch Part
【单选题】 What does the falling intonation on the statement “he is moved to Glasgow.” indicate?
①  I am telling you something you do not know
②  I have not finished yet
③  I am asking a genuine question
④  I know you have told me before.
【单选题】 Which of the following is true about pronunciation teaching?
①  Learners whose native language has similar sounds are less likely to have problems with pronunciation
②  Learners who have more exposure to English need less focus on pronunciation
③  Beginning Chinese learners of English need a certain degree of focus on pronunciation
④  All of the above.
【单选题】 Which of the following do not belong to minimal pair?
①  Will well
②  Till tell
③  Fill fell
④  Well well.
【单选题】 What are the ways of practicing stress?
①  Use gestures
②  Use the voice
③  Use the blackboard
④  All of the above.
【单选题】 Which of the following belong to pronunciation perception practice?
①  using minimal pairs, odd one out
②  Which order, completion
③  Same or different
④  All of the above.
【单选题】 Which of the following is the time when students work as a whole class?
①  When all the students are under the control of the teacher
②  When students work in pairs on an exercise or a task
③  When students work in small groups
④  When students are expected to work on their own at their own speed.
【单选题】 What role does a teacher play in the following activity? While doing a writing task either individually or in groups, the students need to use a particular word they don’t know. So they ask the teacher.
①  Controller
②  Assessor
③  participant
④  Resource-provider.