问题 问答题 简答题

机组升速过程中的注意事项?

答案

参考答案:

①机组升速过程中,在任何转速下,当汽轮发电机组任何一个轴承振动达到0.254mm时,立即脱扣汽机,按紧急停机处理。

②机组升速过程中,当振动达到报警值时.进行如下处理:

③立即进行转速保持,若在共振区域内,则将转速降至共振区域以下再进行保持。

④保持15分钟后,如果振动减少或稳定,则升速200r/min,若升速至共振区域内,再升至共振区域以上10r/min进行保持,如在此转速下不产生报警则允许继续升速。

⑤如果保持15分钟后,振动增加,则降速200r/min,若降至共振转速范围内,应再降至共振转速以下进行保持,若转速必须降至600r/min以下时,注意监视转子偏心度,当偏心度>0.076mm时停机,进行盘车,直至偏心度<0.076mm方可再次启动。

⑥机组升速过程中,应严密监视高压蒸汽室内外壁金属温差,其值应保持在“汽机蒸汽室内外壁金属温度”曲线允许范围内。

⑦在机组转速<600r/min,应对汽机偏心度进行监视,当机组转速>600r/min时,应对汽机振动进行监视,当机组升速至共振区域内时,应严密监视各轴承振动情况。

⑧禁止在共振区域内保持转速。

⑨当机组在冲过临界转速区域时,升速率会自动变为300r/min,之后又自动恢复原设定值。

选择题
单项选择题

This was one of my experiences (1) . When I was in my 30s, I was working for a large international company which had its head office in London. I was working in the (2) department.

The company had a training centre which was just outside London. Different courses were held there throughout (3) and I (4) go on one training course a year. These usually started (5) a Sunday evening and lasted six days.

Once I was (6) a week’s training course with about forty (7) sales people. I was in the bar on the Friday evening and suddenly a woman who was (8) behind the bar asked mea curious question. "I hope you don’t (9) my asking," she said, "but I’ve been (10) about it all week. Have you got a sister (11) Mary" The woman’s name was June. And she used to do various jobs at the training centre. She worked in the office, she organized all the food and drink for the centre and she worked in the bar at lunchtime and in the evening.

My answer (12) June’s question was "Yes", and June said, "I thought (13) . I met her last September when she was organizing a course here. " At that time, my sister was working for (14) company but in a different part of the country. That was (15) she came to be at the training centre.

(16) surprised me was how June guessed we were brother and sister. Three things made it even more (17) . First, she had met my sister six months before she met me. Second, they have about sixty new people every week at the training centre. So about one thousand five hundred people had (18) the centre in those six months. And (19) , my sister is married, so she doesn’t have the same family name as me.

We’re not (20) , but I guess we must look quite like each other.

17().

A.surprising

B.surprised

C.strange

D.puzzled