【单选题】
一般额定电压为380V的三相异步电动机，用___V的兆欧表测量绝缘电阻应大于0.5MΩ才可以使用。
A. 250
B. 500
C. 1000
D. 2500
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相关试题
【单选题】
电烙印是由于电流的___而造成的。
A. 电流的热效应
B. 电流的化学效应
C. 机械效应
D. 金属微粒渗入皮肤
【单选题】
笼形异步电动机转子铁芯一般都采用斜槽结构，其原因是___。
A. 简化制造工艺
B. 增加转子导体的有效长度
C. 增加转矩
D. 改善电动机的启动及运行性能
【单选题】
用户由专用的变压器供电时，如电动机容量小于变压器容量的___时，允许直接启动。
A. 0.1
B. 0.2
C. 0.3
D. 0.4
【单选题】
电路一般都是由电源、负载、中间环节___基本部分组成的。
【单选题】
中间继电器的触点数量比较多，可以将___信号转变为多路信号。
【单选题】
绝缘电阻通常用兆欧（摇表）表测定，摇表测量实际上是给被测物加上___。
A. 低压
B. 直流电压
C. 交流电压
D. 脉动电压
【单选题】
QJ23型单臂电桥的比率臂共有___固定的比例。
【单选题】
建筑物应根据其重要性，使用性质，发生雷电的可能性及后果，防雷标准要求分为___类。
【单选题】
螺旋式熔断器接线时要注意，电源进线接在瓷底座的___接线端上。
A. 金属螺纹壳
B. 顶芯
C. 任一接线端子
D. 无安全要求
【单选题】
绕线转子异步电动机与笼型异步电动机的主要区别是绕线转子异步电动机的转子采用___。
A. 三相笼形
B. 三相转子
C. 三相对称绕组
D. 三相非对称
【单选题】
荧光灯开始工作后，镇流器起着___和限制电流的作用。
【单选题】
当电路发生___或严重过载时，熔断器中的熔体将自动熔断。
【单选题】
工程中由于___而导致RCD动作的案例较为常见。
A. 中性线接地
B. PEN线重复接地
C. PE接地
D. 相线接地
【单选题】
III类电动工具外壳均为___。
A. 全金属
B. 全塑料
C. 铝合金
D. 铝塑材料
【单选题】
为了保证在杆上作业时人体平稳，不应使踏板___。
【单选题】
电动机型号Y2-132S-4上4的含义___。
A. 机座类别
B. 中心高度
C. 磁极对数
D. 绝缘等级
【单选题】
目前国产电机使用的绝缘材料等级为B、F、___、C4。
【单选题】
一般来说电击比电伤的伤害程度要___。
A. 轻
B. 严重得多
C. 较轻一些
D. 好一些
【单选题】
三相异步电动机旋转磁场的旋转方向决定于通入定子绕组中的三相交流电源___。
【单选题】
载流导体受到作用力的方向可由___判断。
A. 左手定则
B. 右手定则
C. 右手螺旋定则
D. 电磁感应
【单选题】
摆脱概率为99.5%，成年男性和成年女性的摆脱电流约为9mA和___mA。
【单选题】
磁电式仪表的灵敏度和精确度较高，刻度盘分度均匀。可直接___。
A. 测量直流电
B. 测量交流电
C. 测量交、直流
D. 测量频率
【单选题】
在电气设备上工作，应填写工作票或按命令执行，其方式有___种。
【单选题】
二氧化碳灭火器可用于___V以下的带电灭火。
A. 220
B. 380
C. 500
D. 600
【单选题】
作废的操作票，应注明“作废”字样，已操作完毕的操作票注明“已执行”，保存___个月。
【单选题】
电度表应垂直安装，安装时表箱底部对地面的垂直距离一般为___。
A. 1.5
B. 1.8
C. 2
D. 2.2
【单选题】
在三相四线制配电系统中，中性线（N）的允许载流量不应___线路中最大不平衡负荷电流。
A. 大于
B. 等于
C. 小于
D. 大于等于
【单选题】
室内灯具灯头使用的导线最小截面积，铜线不得小于0.5mm2，铝线不得小于___mm2。
A. 0.75
B. 1
C. 1.5
D. 2.5
【单选题】
万能转换开关系统由许多接触单元组成，最多可达___层。
【单选题】
电位是衡量电荷在电路中某点所具有能量的物理量，电位是___。
A. 相对量
B. 绝对量
C. 可参考
D. 不确定
【判断题】
对已停电的线路或设备，不论其经常接入的电压表或其他信号是否指示无电，可作为无电压的根据。
【判断题】
剩余电流动作保护器能在0.1S内切断电源。
【判断题】
工频电压220V作用下的人体电阻只有50V时的一半。
【判断题】
由于屏护装置不直接与带电体接触或对其没有严格规定，可以随便处置。
【判断题】
对防雷接地装置应和其他接地装置一样，应分别定期检查和测定。
【判断题】
导线架设时，低压线路面向负荷从左侧起L1、N、L2、L3。
【判断题】
周围有大面积接地导体或金属物件应采用12V的安全特低电压。
【判断题】
无论用登高板或脚扣都要用安全带配合使用。
【判断题】
兆欧表在进行测量前要先切断电源，严禁带电测量设备的绝缘。
推荐试题
【单选题】
Almost a quarter of the British population lives in England.
A. A. northeastern
B. B. southeastern
C. C. northwestern
D. D. southwestern
【单选题】
English belongs to the group of Indo-European family of languages.
A. A. Celtic
B. B. Indo-Iranian
C. C. Germanic
D. D. Roman
【单选题】
The introduction of Christianity to Britain added the first element of words to English.
A. A. Danish and Finnish
B. B. Dutch and German
C. C. French and Italian
D. D. Latin and Greek
【单选题】
The evolution of Middle English was reinforced by the influence.
A. A. Norman
B. B. Dutch
C. C. German
D. D. Danish
【单选题】
In Britain, the parliamentary general election is held every years.
A. A. three
B. B. four
C. C. five
D. D. six
【单选题】
has a distinct legal system based on Roman law.
A. A. Wales
B. B. England
C. C. Scotland
D. D. Northern Ireland
【单选题】
Generally speaking, the British Parliament operates on a system.
A. A. single-party
B. B. two-party
C. C. three-party
D. D. multi-party
【单选题】
The policies of the Conservative Party areThe policies of the Conservative Party are characterized by pragmatism and .
A. A. government intervention
B. B. nationalization of enterprises
C. C. social reform
D. D. a belief in individualism
【单选题】
The Labor Party affected the British society greatly in that it .
A. A. set up the National Health Service
B. B. improved public transportation
C. C. abolished the old tax system
D. D. enhanced the economic development
【单选题】
The British economy achieved global dominance by the .
A. A. 1860s
B. B. 1870s
C. C. 1880s
D. D.1890s
【单选题】
In , the British Parliament passed two important acts to establish a welfare state.
A. A. 1945
B. B. 1946
C. C. 1947
D. D. 1948
【单选题】
The in the early 1970s worsened an already stagnant economy in Britain.
A. A. oil crisis
B. B. high inflation rates
C. C. large imports
D. D. unemployment problem
【单选题】
Of the following practices, does not belong to Thatcher’s social welfare reform.
A. A. reducing child benefits
B. B. shortening the unemployment benefits period
C. C. reducing the unemployment
D. D. lowering old age pensions
【单选题】
The Blair government has been successful in all the following aspects except .
A. A. limiting government spending
B. B. keeping inflation under control
C. C. reducing unemployment
D. D. reducing inequality
【单选题】
Britain has devoted of its land area to agriculture.
A. A. 54%
B. B. 64%
C. C. 74%
D. D.84%
【单选题】
Britain’s important fishing areas include all the following except .
A. A. the North Sea
B. B. the English Channelnnel
C. C. The sea area around Ireland
D. D. The sea area between Britain and Ireland
【单选题】
Coal mining industry in Britain provides of the energy consumed in the country.
A. A. 1/3
B. B. 1/4
C. C. 1/5
D. D. 2/3
【单选题】
The car industry in Britain in mostly .
A. A. foreign-owned
B. B. state-owned
C. C. joint-venture
D. D. privately-owned
【单选题】
Of the following sectors in Britain, has experienced spectacular growth since the end of Word War II.
A. A. agriculture
B. B. energy industry
C. C. service industry
D. D. manufacturing industry
【单选题】
Samuel Johnson’s dictionary was influential in establishing a standard form of .
A. A. grammar
B. B. handwriting
C. C. spelling
D. D. pronunciation
【单选题】
At present, nearly of the world’s population communicate in English.
A. A. half
B. B. a quarter
C. C. one third
D. D. one fifth
【单选题】
The attack on Rome ended the Roman occupation in Britain in 410.
A. A. Norman
B. B. Danish
C. C. Celtic
D. D. Germanic
【单选题】
By the late 7th century, became the dominant religion in England.
A. A. Celtic Christianity
B. B. Anglo-Saxon Christianity
C. C. Germanic Christianity
D. D. Roman Christianity
【单选题】
Westminster Abbey was built at the time of .
A. A. St. Augustine
B. B. Edward the Confessor
C. C. William the Conqueror
D. D. Alfred the Great
【单选题】
The marked the establishment of feudalism in England.
A. A. Viking invasion
B. B. signing of the Magna Carta
C. C. Norman Conquest
D. D. Adoption of common law
【单选题】
The end of the Wars of the Roses led to the rule of .
A. A. the House of Valois
B. B. the House of York
C. C. the House of Tudor
D. D. the House of Lancaster
【单选题】
The direct cause for the Religious Reformation was King Henry VIII’s effort to .
A. A. divorce his wife
B. B. break with Rome
C. C. support the Protestants
D. D. declare his supreme power over the church
【单选题】
The English Civil War broke out in 1642 between .
A. A. Protestants and Puritans
B. B. Royalists and Parliamentarians
C. C. nobles and peasants
D. D. aristocrats and Christians
【单选题】
was passed after the Glorious Revolution.
A. A. Bill of Rights
B. B. Act of Supremacy
C. C. Provisions of Oxford
D. D. Magna Carta
【单选题】
The Industrial Revolution was aThe Industrial Revolution was accomplished in Britain by the middle of the century.
A. A. 17th
B. B. 18th
C. C. 19th
D. D. 20th
【单选题】
Britain faced strong challenges in its global imperial dominance by the beginning of the century.
A. A. 17th
B. B. 18th
C. C. 19th
D. D. 20th
【单选题】
As a revising chamber, the House of Lords is expected to the House of Commons.
A. A. rival
B. B. complement
C. C. criticize
D. D. inspect
【单选题】
The British government is characterized by a division of powers between three of the following branches with the exception of the .
A. A. judiciary
B. B. legislature
C. C. monarchy
D. D. executive
【单选题】
The importance of the British monarchy can be seen in its effect on .
A. A. passing the bills
B. B. advising the government
C. C. political parties
D. D. public attitude
【单选题】
British Cabinet works on the principle of .
A. A. collective responsibility
B. B. individual responsibility
C. C. defending the collectivism
D. D. defending the individuals
【单选题】
The main duty of the British Privy Council is to .
A. A. make decisions
B. B. give advice
C. C. pass bills
D. D. supervise the Cabinet
【单选题】
is the first African-American winner of the Nobel Prize for Literature.
A. A.Ralph Ellison
B. B. Tony Morrison
C. C. Richard Wright
D. D. James Baldwin
【单选题】
Of the following writers, is Not a Nobel Prize winner.
A. A. Alice Walker
B. B. Ernest Hemingway
C. C. William Faulkner
D. D. Eugene O’Neil
【单选题】
Of the following books, is NOT written by Ernest Hemingway.
A. A. The Sun Also Rises
B. B. The Sound and the Fury
C. C. A Farewell to Arms
D. D. For Whom the Bell Tolls
【单选题】
F. Scott Fitzgerald’s finest novel is , and its theme is about
A. A. The Great Gatsby, the American Dream
B. B. Tender is the Night, love
C. C. Tales of the Jazz Age, the loss of oneself
D. D. The Beautiful and the Damned, the evil of human nature
