2022 low voltage electrician retraining question bank and online simulation examination

Source of question bank ： Safety production simulation test, a little public official account.

2022 Low voltage electrician question bank is a necessary exercise before the examination of low voltage electrician exercise questions ！2022 The low voltage electrician recurrent training question bank and online simulation examination are compiled according to the new version of the teaching material outline of low voltage electrician . Pass the low-voltage electrician test and improve the pass rate .

1、【 Single topic selection 】 The power supply for general lighting is preferred ( )V.（  A  ）

A、220

B、380

C、36

2、【 Single topic selection 】 There are many main electrical appliances , Among them is ( ).（  B  ）

A、 Contactor

B、 Travel switch

C、 Thermal relay

3、【 Single topic selection 】 Fire extinguishing with spray water gun , But for the sake of safety , Fire extinguishing personnel shall wear insulating gloves , Wearing insulating boots also requires water gun head ( ).（  A  ）

A、 Grounding

B、 It must be made of plastic

C、 It can't be made of metal

4、【 Single topic selection 】 The power of the capacitor belongs to ( ).（  B  ）

A、 Active power

B、 Reactive power

C、 Apparent power

5、【 Single topic selection 】 In case of electrical fire in the workshop , The power supply should be cut off first , The way to cut off the power supply is ( ).（  B  ）

A、 Open the knife switch

B、 Open the circuit breaker or magnetic switch

C、 Report to the person in charge and request to disconnect the main power supply

6、【 Single topic selection 】 Before measuring the capacitor, you must ( ).（  C  ）

A、 Wipe clean

B、 Fully charged

C、 Fully discharge

7、【 Single topic selection 】 From the actual accident, we can see ,70% The above accidents are related to ( ) of .（  C  ）

A、 Technical level

B、 Human emotion

C、 Human error

8、【 Single topic selection 】 When measuring resistance with a multimeter , The black probe is connected to the power supply in the meter ( ).（  C  ）

A、 Two poles

B、 Negative pole

C、 Positive pole

9、【 Single topic selection 】 There are many electrostatic protection measures , The following common and effective methods to eliminate static electricity of equipment shell are ( ).（  A  ）

A、 Grounding

B、 Connect to zero

C、 concatenated

10、【 Single topic selection 】 When selecting voltmeter , Its internal resistance ( ) The resistance of the measured load is good .（  B  ）

A、 Far less than

B、 Far greater than

C、 be equal to

11、【 Single topic selection 】 According to its action mode, low-voltage electrical appliances can be divided into automatic switching electrical appliances and ( ) Electrical appliances .（  A  ）

A、 Non automatic switching

B、 Non electric

C、 Non mechanical

12、【 Single topic selection 】 Low voltage lines and equipment newly installed and overhauled , The insulation resistance shall not be less than ( )MΩ.（  B  ）

A、1

B、0.5

C、1.5

13、【 Single topic selection 】 The grounding resistance of anti-static shall not be greater than ( )Ω.（  C  ）

A、10

B、40

C、100

14、【 Single topic selection 】 Belonging to power distribution appliances are ( ).（  B  ）

A、 Contactor

B、 Fuse

C、 resistor

15、【 Single topic selection 】 When the current relay is used, its suction coil is directly or through the current transformer ( ) In the controlled circuit .（  B  ）

A、 parallel connection

B、 Series connection

C、 Series or parallel

16、【 Single topic selection 】 The insulation resistance of lines or equipment is measured by ( ) measurement .（  B  ）

A、 The resistance gear of the multimeter

B、 Megger

C、 Grounding megger

17、【 Single topic selection 】 Alarm type leakage protector should be installed without automatically cutting off the power supply ( ).（  C  ）

A、 Guest house socket circuit

B、 Electrical equipment for production

C、 Fire elevator

18、【 Single topic selection 】 The AC voltage indicated by the standard of general electrical appliances or instruments 、 The value of the current is ( ).（  B  ）

A、 Maximum

B、 Valid values

C、 Average

19、【 Single topic selection 】 The grounding resistance measuring instrument is mainly composed of a hand generator 、( )、 Potentiometer , And galvanometer .（  A  ）

A、 Current transformer

B、 Voltage transformer

C、 transformer

20、【 Single topic selection 】 The mechanical life of AC contactor refers to the number of operations without load , Generally up to ( ).（  B  ）

A、10 Less than 10000 times

B、600 to 1000 Ten thousand times

C、10000 More than ten thousand times

21、【 Single topic selection 】 When the human body contacts two-phase conductors in live equipment or lines at the same time , An electric current flows from one phase through the human body into another , This phenomenon of electric shock is called ( ) Get an electric shock .（  B  ）

A、 single-phase

B、 two-phase

C、 Inductive electricity

22、【 Single topic selection 】 according to 《 Allowable deviation of power quality supply voltage 》 Regulations ,10kV The allowable deviation of three-phase power supply voltage of and below is... Of the rated voltage ( ).（  B  ）

A、±5%

B、±7%

C、±10%

23、【 Single topic selection 】 Voltage of a certain phase 220V In the three-phase four wire system , Working grounding resistance RN=2.8Ω, The electrical equipment in the system adopts grounding protection , The grounding resistance is RA=3.6Ω, If there is leakage of electrical equipment , Before troubleshooting, the voltage of leakage equipment to ground is ( )V.（  B  ）

A、34.375

B、123.75

C、96.25

24、【 Single topic selection 】 Capacitors belong to ( ) equipment .（  C  ）

A、 dangerous

B、 motion

C、 static

25、【 Single topic selection 】 The power incoming line of screw fuse shall be connected to ( ).（  B  ）

A、 Top

B、 lower end

C、 front end

26、【 Single topic selection 】 According to the line voltage level and user object , Power lines can be divided into distribution lines and ( ) line .（  C  ）

A、 power

B、 lighting

C、 Power transmission

27、【 Single topic selection 】 Components with inverse time ampere second characteristics have short-circuit protection and ( ) The ability to protect .（  C  ）

A、 temperature

B、 mechanical

C、 overload

28、【 Single topic selection 】

The electrical diagram of the circuit breaker is .

（  A  ）

A、

B、

C、

29、【 Single topic selection 】 The composition of the travel switch includes ( ).（  C  ）

A、 Coil part

B、 The protection part

C、 Reaction system

30、【 Single topic selection 】 Low voltage fuse , It is widely used in low-voltage power supply and distribution system and control system , It is mainly used for ( ) Protect , Sometimes it can also be used for overload protection .（  B  ）

A、 Quick break

B、 A short circuit

C、 Over current

31、【 Single topic selection 】 Low voltage electrical appliances can be classified as low-voltage distribution appliances and ( ) Electrical appliances .（  A  ）

A、 Low voltage control

B、 Voltage control

C、 Low voltage electric

32、【 Single topic selection 】 The conductor joints shall be in close contact and ( ) etc. .（  B  ）

A、 Keep pulling

B、 Firm and reliable

C、 No heat

33、【 Single topic selection 】 The grounding wire shall be multi strand soft bare copper wire , Its cross-sectional area shall not be less than （）m㎡.（  C  ）

A、6

B、10

C、25

34、【 Single topic selection 】 In semiconductor circuits , The quick fuse is mainly used as the （） Protect .（  A  ）

A、 A short circuit

B、 Overvoltage

C、 Overheated

35、【 Single topic selection 】 The normal working state of the zener diode is ( ).（  C  ）

A、 On state

B、 As of

C、 Reverse breakdown state

36、【 Single topic selection 】 Transformer and high voltage switchgear , The main measures to prevent damage caused by lightning intrusion are ( ).（  A  ）

A、 Install lightning arrester

B、 Installation of lightning conductor

C、 Install lightning protection network

37、【 Single topic selection 】Ⅱ This kind of hand-held electric tool is equipped with ( ) Insulated equipment .（  C  ）

A、 basic

B、 protective

C、 double

38、【 Single topic selection 】 Low voltage circuit breakers are also called ( ).（  C  ）

A、 Knife switch

B、 Main switch

C、 Automatic air switch

39、【 Single topic selection 】 In thunderstorm weather , Doors, windows, etc. should be closed , The purpose is to prevent ( ) Break into the house , Cause fire 、 Explosion or casualties .（  A  ）

A、 Spherical thunder

B、 Induction mine

C、 Direct ray

40、【 Single topic selection 】 In power control system , The most widely used is ( ) Type AC contactor .（  B  ）

A、 Pneumatic

B、 electromagnetism

C、 Hydraulically

41、【 Single topic selection 】 For low voltage distribution networks , The distribution capacity is 100KW Following time , The grounding resistance of equipment protective grounding shall not exceed ( )Ω.（  A  ）

A、10

B、6

C、4

42、【 Single topic selection 】 When checking the socket , The electric pen is not bright at both holes of the socket , The first judgment is ( ).（  B  ）

A、 A short circuit

B、 The phase line is broken

C、 The zero line is broken

43、【 Single topic selection 】 During low voltage live working ,( ).（  A  ）

A、 Wear insulating gloves , And someone to watch

B、 Wear insulating gloves , Don't be supervised

C、 There is no need to wear insulating gloves when someone is watching

44、【 Single topic selection 】 On each single-phase circuit in the lighting system , The number of lamps and sockets should not exceed ( ) individual .（  B  ）

A、20

B、25

C、30

45、【 Single topic selection 】 The inside of the inductive fluorescent lamp ballast is ( ).（  B  ）

A、 electronic circuit

B、 coil

C、 Oscillating circuit

46、【 Single topic selection 】 When installing electrical circuits , The connection process between wires or between wires and electrical bolts that is most likely to cause fire is ( ).（  A  ）

A、 Copper wire and aluminum wire are twisted

B、 Aluminum wire is twisted with aluminum wire

C、 Copper aluminum transition joint crimping

47、【 Single topic selection 】 The current of ventricular fibrillation is about ( )mA.（  C  ）

A、16

B、30

C、50

48、【 Single topic selection 】 Low voltage electrician operation refers to ( )V Install the following electrical equipment 、 debugging 、 Jobs that run operations, etc .（  C  ）

A、250

B、500

C、1000

49、【 Judgment questions 】 The slip rate of an asynchronous motor is the ratio of the difference between the speed of the rotating magnetic field and the speed of the motor to the speed of the rotating magnetic field .（  √  ）

50、【 Judgment questions 】 Megger before use , There is no need to check whether the megger is in good condition , It can directly measure the insulation of the tested equipment .（  ×  ）

51、【 Judgment questions 】 In general , The single-phase electric shock of grounded power grid is less dangerous than that of ungrounded power grid .（  ×  ）

52、【 Judgment questions 】 The economic principles that should be followed in selecting electrical appliances are their own economic value and use value , No loss due to unreliable operation .（  √  ）

53、【 Judgment questions 】 When the leakage circuit breaker has leakage in the protected circuit or someone gets an electric shock , The zero sequence current transformer generates induced current , After releasing, the release acts , To cut off the circuit .（  √  ）

54、【 Judgment questions 】 Shunt capacitor can reduce voltage loss .（  √  ）

55、【 Judgment questions 】 Automatic adjustment and compensation of frequency is a function of thermal relay .（  ×  ）

56、【 Judgment questions 】 After the leakage switch trips , It is allowed to check the line by means of shunt power failure and power transmission .（  √  ）

57、【 Judgment questions 】 When installing the iron clad switch, the shell must be reliably grounded .（  √  ）

58、【 Judgment questions 】 When the capacitor explodes , Check immediately .（  ×  ）

59、【 Judgment questions 】 When measuring current, the ammeter shall be connected in series with the circuit under test .（  √  ）

60、【 Judgment questions 】 Power frequency current is more likely to cause skin burns than high-frequency current .（  ×  ）

61、【 Judgment questions 】 The button depends on the occasion of use , The optional types are open 、 Waterproof 、 Corrosion resistant 、 Protective, etc .（  √  ）

62、【 Judgment questions 】 The rotor and stator of three-phase motor can work only when they are energized at the same time .（  ×  ）

63、【 Judgment questions 】 The frequency on the nameplate of the AC motor is the frequency of the AC power supply used by the motor .（  √  ）

64、【 Judgment questions 】 In a DC circuit , The positive pole is usually marked in brown .（  √  ）

65、【 Judgment questions 】 To ensure the safety of zero line , The zero line of three-phase four wire must be equipped with fuse .（  ×  ）

66、【 Judgment questions 】 The character symbol of time relay is KT.（  √  ）

67、【 Judgment questions 】 According to the specification , When copper core wire is used for pipe insulated conductor , The cross-sectional area shall not be less than 1mm².（  √  ）

68、【 Judgment questions 】 The power transformation and distribution equipment shall be equipped with perfect screen protection device .（  √  ）

69、【 Judgment questions 】 The positioning structure of universal transfer switch generally adopts the radial structure of roller clamping shaft .（  ×  ）

70、【 Judgment questions 】 Low voltage circuit breaker is an important control and protection appliance , Circuit breakers are equipped with arc extinguishing devices , Therefore, the load can be safely closed 、 Opening .（  √  ）

71、【 Judgment questions 】 Speed relay is mainly used for reverse braking of motor , Therefore, it is also called reverse braking relay .（  √  ）

72、【 Judgment questions 】 Measure the ground insulation resistance and phase to phase insulation resistance of the motor , Megger is often used , Instead of using a multimeter .（  √  ）

73、【 Judgment questions 】 After the multimeter is used , The change-over switch can be placed in any position .（  ×  ）

74、【 Judgment questions 】 The downlead of lightning protection device shall meet sufficient mechanical strength 、 Requirements for corrosion resistance and thermal stability , If steel strand is used , Its section shall not be less than 35mm².（  ×  ）

75、【 Judgment questions 】 Insulation aging is just a chemical change .（  ×  ）

76、【 Judgment questions 】220V The maximum value of AC voltage is 380V.（  ×  ）

77、【 Judgment questions 】 In explosion hazardous areas , Three phase four wire system shall be adopted , Single phase three wire power supply .（  ×  ）

78、【 Judgment questions 】 For safety and reliability , All switches shall control phase line and zero line at the same time .（  ×  ）

79、【 Judgment questions 】 When connecting wires, anti-corrosion measures must be taken .（  √  ）

80、【 Judgment questions 】 Characteristics of fuse , The higher the voltage through the melt , The shorter the fusing time .（  ×  ）

81、【 Judgment questions 】 The voltage is measured with a voltmeter , When measuring, it is connected in series in the circuit .（  ×  ）

82、【 Judgment questions 】 Special operation personnel must be at least 20 One year old , And no more than the national legal retirement age .（  ×  ）

83、【 Judgment questions 】 In high pressure operation , The distance between the human body or the tools it carries and the electrified body shall not be less than 0.7m.（  √  ）

84、【 Judgment questions 】 The capacitor room shall be well ventilated .（  √  ）

85、【 Judgment questions 】 The automatic air switch has overload 、 Short circuit and undervoltage protection .（  √  ）

86、【 Judgment questions 】 The greater the internal resistance of the voltmeter, the better .（  √  ）

87、【 Judgment questions 】 The current on each branch of a parallel circuit is not necessarily equal .（  √  ）

88、【 Judgment questions 】 The voltage at which the insulator is broken down is called the breakdown voltage .（  √  ）

89、【 Judgment questions 】 The rated voltage is 380V The fuse can be used in 220V In the line of .（  √  ）

90、【 Judgment questions 】 When checking with an electric pen , The light of the electric pen indicates that there must be electricity in the line .（  ×  ）

91、【 Judgment questions 】 It is forbidden to install bedside switch in civil residence .（  √  ）

92、【 Judgment questions 】 This method of changing rotor resistance speed regulation is only applicable to wound asynchronous motor .（  √  ）

93、【 Judgment questions 】 After the wire is connected, the smaller the distance between the joint and the insulating layer, the better .（  √  ）

94、【 Judgment questions 】 The person who gets an electric shock is unconscious , There's a heartbeat , But breathing stops , Mouth to mouth artificial respiration should be performed immediately .（  √  ）

95、【 Judgment questions 】 Power on time increases , The body's electrical resistance increases due to sweating , Resulting in a decrease in the current through the human body .（  ×  ）

96、【 Judgment questions 】 The larger the capacity of the compensation capacitor, the better .（  ×  ）

97、【 Judgment questions 】 The character symbol of time relay is KM.（  ×  ）

98、【 Judgment questions 】 Objects with electrical conductivity between conductors and insulators are called semiconductors .（  √  ）

99、【 Judgment questions 】 Hand held electric tools can be classified in two ways , That is, it is classified according to working voltage and moisture-proof degree .（  ×  ）

100、【 Judgment questions 】 Equipment with motor , Before the motor is powered on, check the auxiliary equipment and mounting base of the motor , Grounding, etc , Power on after normal operation .（  √  ）

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