问题 问答题 简答题

试述KL0400[2]一1T1型空调控制柜中过压、欠压保护电气控制原理。

答案

参考答案:

(1)过压、欠压继电器FOV、FLV接在18号线与1R之间接人KT3的常开触点,这个电路起到过电压、欠压和失压保护作用。

(2)过压保护控制:若电源电压超过额定电压值的115%(253v)时,过压继电器FOV动作,断开控制回路电源,系统停止工作,使电器元件及设备不会因电压过高而损坏。

(3)欠压保护控制:若电源电压低于额定电压值的85%(187v)时,欠压继电器FLV动作,断开控制回路电源,系统停止工作,起到欠压保护作用。

(4)为避免误动作,设置了继电器KT3,延时0.5s用以鉴别是瞬时欠压(过压),还是故障欠压(过压),保证空调机组在187~253v电压之问正常工作。

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阅读理解

There was once a man called Mr. Flowers, and flowers were his only joy in life. He spent all his free time in one of his four glass-houses and grew flowers of every color, with long and difficult names, for competitions. He tried to grow a rose of a new color to win the silver cup for the Rose of the Year.

Mr. Flowers’ glass-houses were very near to a middle school. Boys of around thirteen of age were often tempted (引诱) to throw a stone or two at one of Mr. Flowers’ glass-houses. So Mr. Flowers did his best to be in or near his glass-houses at the beginning and end of the school day.

But it was not always possible to be on watch at those times. Mr. Flowers had tried in many ways to protect his glass, but nothing that he had done had been useful. He had been to school to report to the headmaster; but this had not done any good. He had tried to drive away the boys that threw stones into his garden; but the boys could run faster than he could, and they laughed at him from far away. He had even picked up all the stones that he could find around his garden, so that the boys would have nothing to throw; but they soon found others.

At last Mr. Flowers had a good idea. He put up a large notice made of good, strong wood, some meters away from the glass-houses. On it he had written the words: DO NOT THROW STONES AT THIS NOTICE. After this, Mr. Flowers had no further trouble; the boys were much more tempted to throw stones at the notice than at the glass-houses.

小题1:It was Mr. Flowers’ hope to ________.

A.build glass-houses in his free time 

B.grow the Rose of the Year in a silver cup

C.win a silver cup for growing a rose of a new color

D.grow a rose with the longest name.小题2:Boys were often tempted to ________.

A.throw stones at Mr. Flowers’ glass-house 

B.throw stones at Mr. Flowers from their school

C.be in or near by Mr. Flowers’ glass-houses 

D.play with Mr. Flowers near his glass-houses小题3:Mr. Flowers stayed in or near by his glass-houses _______.

A.at times when school-boys were walking near them

B.all the school day when there were no boys about

C.where he could not be seen by the boys passing

D.in his free time at the beginning and end of the school day小题4:Mr. Flowers had tried to ______ to protect his glass.

A.be on watch in his free time

B.ask the headmaster for help

C.pick up all the stones around his garden

D.do all the above小题5:Mr. Flowers’ good idea was to ______.

A.write some words on the glass

B.put up a large notice to cover his glass-houses

C.give the boys something else to throw stones at

D.send for policemen