相关试题
【判断题】
事故照明不允许和其它照明共用同一线路。
【判断题】
接了漏电开关之后，设备外壳就不需要再接地或接零了。
【判断题】
低压验电器可以验出500V以下的电压。
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锡焊晶体管等弱电元件应用100W的电烙铁。
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为改善电动机的启动及运行性能，笼形异步电动机转子铁芯一般采用直槽结构。
【判断题】
用星-三角降压启动时，启动转矩为直接采用三角形联结时启动转矩的1/3。
【判断题】
转子串频敏变阻器启动的转矩大，适合重载启动。
【判断题】
同一电器元件的各部件分散地画在原理图中，必须按顺序标注文字符号。
【判断题】
对电机轴承润滑的检查，可通电转动电动机转轴，看是否转动灵活，听有无异声。
【判断题】
使用改变磁极对数来调速的电机一般都是绕线型转子电动机。
【判断题】
电机在检修后，经各项检查合格后，就可对电机进行空载试验和短路试验。
【判断题】
根据用电性质，电力线路可分为动力线路和配电线路。
【判断题】
导线连接后接头与绝缘层的距离越小越好。
【判断题】
导线接头的抗拉强度必须与原导线的抗拉强度相同。
【判断题】
在电压低于额定值的一定比例后能自动断电的称为欠压保护。
【判断题】
在我国，超高压送电线路基本上是架空敷设。
【判断题】
一般情况下，接地电网的单相触电比不接地的电网的危险性小。
【判断题】
通电时间增加，人体电阻因出汗而增加，导致通过人体的电流减小。
【判断题】
触电者神志不清，有心跳，但呼吸停止，应立即进行口对口人工呼吸。
【判断题】
绝缘棒在闭合或拉开高压隔离开关和跌落式熔断器，装拆携带式接地线，以及进行辅助测量和试验使用。
【判断题】
常用绝缘安全防护用具有绝缘手套、绝缘靴、绝缘隔板、绝缘垫、绝缘站台等。
【判断题】
使用脚扣进行登杆作业时，上、下杆的每一步必须使脚扣环完全套入并可靠地扣住电杆，才能移动身体，否则会造成事故。
【判断题】
在高压操作中，无遮拦作业人体或其所携带工具与带电体之间的距离应不少于0.7m。
【判断题】
保护接零适用于中性点直接接地的配电系统中。
【判断题】
单相220V电源供电的电气设备，应选用三极式漏电保护装置。
【判断题】
机关、学校、企业、住宅等建筑物内的插座回路不需要安装漏电保护装置。
【判断题】
雷击产生的高电压和耀眼的光芒可对电气装置和建筑物及其他设施造成毁坏，电力设施或电力线路遭破坏可能导致大规模停电。
【判断题】
雷电按其传播方式可分为直击雷和感应雷两种。
【判断题】
雷电时，应禁止在屋外高空检修、试验和屋内验电等作业。
【判断题】
当电容器测量时万用表指针摆动后停止不动，说明电容器短路。
【判断题】
电容器放电的方法就是将其两端用导线连接。
【判断题】
按钮根据使用场合，可选的种类有开启式、防水式、防腐式、保护式等。
【判断题】
组合开关在选作直接控制电机时，要求其额定电流可取电动机额定电流的2~3倍。
【判断题】
热继电器的保护特性在保护电机时，应尽可能与电动机过载特性贴近。
【判断题】
自动切换电器是依靠本身参数的变化或外来讯号而自动进行工作的。
推荐试题
【单选题】
Nobody noticed the thief slip into the house because the lights happened to _____.___
A. be put up
B. give in
C. be turned on
D. go out
【单选题】
----- John， may I ask you a favour？ ----- _________
A. I’m sorry， but why？
B. Sure，what is it？
C. Yes，you could.
D. I’d love to，and I’m busy.
【单选题】
The two thieves fled the town separately， _______ a bag.___
A. each carrying
B. whose that watch is
C. whose watch is that
D. whose watch is
【单选题】
Her heart _____ faster when she entered the exam hall.___
A. jumped
B. sank
C. beat
D. hit
【单选题】
The taxi driver was put in_____prison because his car had knocked down a child.His wife went to_____ prison to see him twice a month.___
A. /； /
B. the； the
C. /； the
D. the； /
【单选题】
----- Where’s John， do you know？ ----- Oh， _____to hospital.___
A. he’s taken
B. he’ll be taken
C. he’s been taken
D. he’ll take
【单选题】
It was the wealth of the_____pioneer landowner John Harvard that made Harvard University possible.___
A. precious
B. curious
C. anxious
D. prosperous
【单选题】
----- "Where is your college located, John?" ----- "It is ________."___
A. on the Fifth Avenue
B. on Fifth Avenue
C. in Fifth Avenue
D. at Fifth Avenue
【单选题】
__________ is she in London than she rings up her old friend Mary.___
A. Scarcely
B. Rarely
C. No sooner
D. Hardly
【单选题】
A fireman discovered the __________ of the fire.___
A. truth
B. reason
C. cause
D. fact
【单选题】
he weather __________ us from climbing the mountain.___
A. discharged
B. disguised
C. disturbed
D. discouraged
【单选题】
I didn't expect to receive a postcard from you！It's really _____my wildest imagination.___
A. behind
B. beyond
C. except
D. through
【单选题】
John Smith is _____ honest young man.___
【单选题】
She __________ in wearing that old – fashioned hat.___
A. insists
B. persists
C. assists
D. consists
【单选题】
Some of the meat came from Canada. How about________？___
A. another
B. the other
C. others
D. the rest
【单选题】
I have brought you ___ flowers for your birthday. ___
A. few
B. a few
C. little
D. a little
【单选题】
I have also experienced many adventures, but nothing that I have seen ___what you have described. ___
A. compares
B. relates
C. resembles
D. assembles
【单选题】
That young man has made so much noise that he ___ not have been allowed attend the concert. ___
A. could
B. must
C. would
D. should
【单选题】
“What is Mary doing at home?” “She is playing ____.”___
A. a piano
B. her piano
C. piano
D. the piano
【单选题】
I’m busy now ,ask him to see me ____ time.___
A. the other
B. some other
C. other
D. another
【单选题】
The child took a spoonful and tasted it carefully __________ it was hot.___
A. in case
B. provided
C. if
D. unless
【单选题】
The French pianist who had been praised very highly __________ to be a great disappointment. ___
A. turned off
B. turned up
C. turned out
D. turned down
【单选题】
“Shall I turn on the television?” – “No, I’d rather not __________ television tonight.”___
A. have watched
B. to watch
C. watch
D. for watching
【单选题】
They said that they had made up their minds to ____the task in spite of the extremely difficult conditions.___
A. carry on
B. carry off
C. carry away
D. carry forward
【单选题】
The two girls are getting on very well and share with each other. ___
A. little
B. much
C. some
D. none
【单选题】
The teacher said that the classroom was empty __________ a few chairs.___
A. but for
B. except for
C. apart from
D. besides
【单选题】
______you choose， make sure that it is a good one. ___
A. What
B. Wherever
C. Whichever
D. Which
【单选题】
Vingo was released from prison_____the successful efforts of his friends to prove his innocence. ___
A. according to
B. as a result of
C. for reasons of
D. with the help of
【单选题】
Entering the room， I found my father __ at the desk and ___ something .___
A. seat... write
B. seated ... wrote
C. seated ... writing
D. seating ... writing
【单选题】
Cake __________ of flour, sugar, egg and some other ingredients. ___
A. contained
B. consists
C. includes
D. composed
【单选题】
Mr. Peter wanted Steve to take half the money, but Steve did not __________ it. ___
A. obtain
B. achieve
C. accept
D. receive
【单选题】
I'd like to take my picture ________stands a high tower. ___
A. where
B. which
C. that
D. there
【单选题】
__________ the English examination I would have gone to the concert last Saturday. ___
A. But for
B. As for
C. In spite of
D. Because of
【单选题】
Cars moved very slowly in the 1920s, but they ______move more quickly than in 1910.___
A. were to can
B. did
C. will
D. can
【单选题】
The little girl needs __________ after her shock. ___
A. being comforted
B. be comforted
C. comforting
D. comforted
【单选题】
The __________ horse ran away from the fire.___
A. having frightened
B. frightening
C. frightened
D. frighten
【单选题】
He is __________ of an actor. ___
A. anybody
B. anything
C. somebody
D. something
【单选题】
You can take ______ seat you like. ___
A. no matter what
B. no matter which
C. what
D. whichever
【单选题】
He changed his name， _____ that nobody would find out what he had done before. ___
A. having thought
B. to think
C. thinks
D. thinking
【单选题】
----- _______is your English teacher？ ----- The one in red. ___
A. who
B. which
C. what
D. where
