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电压互感器在运行中为什么要严防二次侧短路?

答案

参考答案:

电压互感器是一个内阻极小的电压源,正常运行时负载阻抗很大,相当于开路状态,二次侧仅有很小的负载电流,当二次侧短路时,负载阻抗为零,将产生很大的短路电流,会将电压互感器烧坏。因此,电压互感器二次侧短路是电气试验人员的又一大忌。

阅读理解

When someone says, “Well,I guess I’ll have to face the music”, it doesn’t mean that he is planning to go to hear a singer or attend a concert. It is something far less unhappy than you are called in by your leader to explain why you did this and that or why you did not do this or that.

  At some time or another, every one of us has to “face the music”, especially as children. We can all remember father’s angry words “I want to talk to you”. And only because we did not listen to him. What a bad thing it was!

  In the middle or at the end of every term, we students have to “face the music”. The result of the exam will decide whether we will face the music or not. If...that means parents cold faces and contempt (轻视) of the teachers and classmates.

 “To face the music” is well known to every American, young or old. It is at least 100 years old. It really means that you have to do something, no matter how terrible the whole thing might be, because you know you have no choice.

小题1:“To face the music” means “to__________”.

A.do something that we don’t like to

B.go to the theatre

C.go to the music show

D.do something that we want to小题2:In the third paragraph, “If…”really means “If__________”.

A.we don’t do a good job

B.we get an “A” in the exam

C.the exam is easy

D.the exam is difficult小题3:Which of the following is NOT true according to the passage?

A.“To face the music” is well known in the United States.

B.“To face the music” has a history of more than 100 years.

C.The young Americans know what “to face the music” means.

D.Only the old in the United States know the meaning of “to face the music”.

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