2022 low voltage electrician examination content and low voltage electrician simulation examination question bank

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

Pass the safety production simulation exam at one point ：2022 The content of the low-voltage electrician examination in is a theoretical examination topic for students who are preparing for the low-voltage electrician operation certificate , The monthly updated low-voltage electrician simulation examination question bank wishes you to successfully pass the low-voltage electrician examination .

1、【 Single topic selection 】 Transportation of liquefied gas , When the tanker of oil, etc. is running , Metal chain or conductive rubber shall be used at the bottom of the tank car to make it contact with the earth , Its purpose is to ( ).（  B  ）

A、 Neutralize the static charge generated during the running of the tank car

B、 The static charge generated during the running of the leaking tank car

C、 Equipotential between the tank car and the earth

2、【 Single topic selection 】 Wire connector 、 Poor contact of controller contact is an important cause of electrical fire . So-called “ poor contact ”, The essential reason is that ( ).（  C  ）

A、 Contact 、 The change of contact resistance leads to overvoltage

B、 The resistance at the contact point of the contact decreases

C、 Contact 、 The contact resistance increases, resulting in increased power consumption

3、【 Single topic selection 】 The unit of power of a capacitor is ( ).（  A  ）

A、 Lack

B、 watts

C、 volt-ampere

4、【 Single topic selection 】 The long-term allowable current of the conductor connecting the capacitor shall not be less than... Of the rated current of the capacitor ( )%.（  C  ）

A、110

B、120

C、130

5、【 Single topic selection 】 It's flammable 、 Explosive and dangerous places , The power supply line shall adopt ( ) Power supply mode .（  B  ）

A、 Single phase three wire system , Three phase four wire system

B、 Single phase three wire system , Three phase five wire system

C、 Single phase two wire system , Three phase five wire system

6、【 Single topic selection 】 Use a megger to measure the insulation resistance between stator winding and housing phase by phase , When turning the handle , The pointer points to zero , Describe the winding ( ).（  A  ）

A、 Collision shell

B、 A short circuit

C、 Open circuit

7、【 Single topic selection 】 When powered by a dedicated transformer , The motor capacity is less than... Of the transformer capacity ( ), Allow direct startup .（  C  ）

A、60%

B、40%

C、20%

8、【 Single topic selection 】PE Line or PEN The re grounding of other grounding points on the line other than working grounding is called ( ) Grounding .（  C  ）

A、 indirect

B、 direct

C、 repeat

9、【 Single topic selection 】 Hand held electric tools are divided into... According to the protection mode of electric shock ( ) class .（  B  ）

A、2

B、3

C、4

10、【 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

11、【 Single topic selection 】 The advantage of micro motion travel switch is ( ) Action mechanism .（  C  ）

A、 control

B、 Rotating shaft

C、 Energy storage

12、【 Single topic selection 】 The sound of the motor during normal operation , It's smooth 、 Brisk 、( ) And rhythmic .（  B  ）

A、 scream

B、 uniform

C、 friction

13、【 Single topic selection 】 The basic structure of the universal transfer switch has ( ).（  B  ）

A、 Reaction system

B、 Contact system

C、 Coil part

14、【 Single topic selection 】 Relay is a kind of relay according to ( ) To control the circuit “ Connect ” or “ To break off ” An automatic electric appliance .（  A  ）

A、 External input signal ( Electrical or non electrical signals )

B、 Electrical signals

C、 Non electrical signals

15、【 Single topic selection 】 When 10kV In case of electrical fire in the high voltage control system , If the power cannot be cut off , If it is necessary to put out the fire with electricity, the optional fire extinguisher is ( ).（  A  ）

A、 Dry powder fire extinguisher , The distance between the nozzle and the body and the charged body shall not be less than 0.4m

B、 Atomizing water gun , Wear insulating gloves , Wear insulating boots , The water gun head is grounded . The distance between the water gun head and the charged body 4.5m above

C、 Carbon dioxide fire extinguisher , The distance between the nozzle and the charged body shall not be less than 0.6m

16、【 Single topic selection 】 Where the capacitance is in 160KVA The above high-voltage power supply users , The monthly average power factor standard is ( ).（  C  ）

A、0.8

B、0.85

C、0.9

17、【 Single topic selection 】 When several lines are erected on the same pole , It must be ensured that the high-voltage line is on the low-voltage line ( ).（  C  ）

A、 left side

B、 right

C、 upper

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

A、 A short circuit

B、 Overvoltage

C、 Overheated

19、【 Single topic selection 】 When the three-phase symmetrical load is connected into a star , Total three-phase current ( ).（  A  ）

A、 Is equal to zero

B、 Equal to three times the current of one phase

C、 Equal to one of the phase currents .

20、【 Single topic selection 】 Protective grounding of low-voltage power supply lines and lightning protection grounding network of buildings , When sharing is needed , The grounding grid resistance requirements ( ).（  A  ）

A、≤1Ω

B、≤2.5Ω

C、≤10Ω

21、【 Single topic selection 】 Pictured , Insert a... At the fuse “220V40W” The light bulb L0, When only closed S1 when L0 and L1 All dark red ; From this we can determine （）.

（  A  ）

A、L1 The branch wiring is correct

B、L1 The lamp cap is short circuited

C、L1 There is leakage in the branch

22、【 Single topic selection 】 In a closed loop , The current intensity is directly proportional to the electromotive force of the power supply , It is inversely proportional to the sum of internal resistance and external resistance in the circuit , This must be called ( ).（  A  ）

A、 Full circuit Ohm's law

B、 Full circuit current law

C、 Partial circuit Ohm's law

23、【 Single topic selection 】

The graphical symbol of the diode is .

（  A  ）

A、

B、

C、

24、【 Single topic selection 】 When selecting the sensitivity of leakage protection device , Avoid due to normal ( ) Cause unnecessary action and affect the normal power supply .（  A  ）

A、 Leakage current

B、 Leakage voltage

C、 Leakage power

25、【 Single topic selection 】 chart

yes () Contact .2（  B  ）

A、 Delay closing and dynamic closing

B、 Delay opening and closing

C、 Delay breaking action

26、【 Single topic selection 】 The electrical life of AC contactor is about... Of the mechanical life （） times .（  C  ）

A、10

B、1

C、1/20

27、【 Single topic selection 】 The multimeter consists of a meter head 、( ) And transfer switch .（  A  ）

A、 Measuring circuits

B、 coil

C、 The pointer

28、【 Single topic selection 】 The lighting voltage we use is 220V, This value is the of AC ( ).（  A  ）

A、 Valid values

B、 Maximum

C、 Constant value

29、【 Single topic selection 】 Electrical fire is caused by the existence of dangerous temperature , The dangerous temperature is mainly caused by ( ).（  C  ）

A、 Light equipment load

B、 Voltage fluctuation

C、 The current is too high

30、【 Single topic selection 】 Especially humid places should adopt ( )V Safe extra low voltage .（  C  ）

A、42

B、24

C、12

31、【 Single topic selection 】 When the combined switch is used for reversible control of motor ,( ) Allow reverse connection .（  C  ）

A、 It is not necessary to stop after the motor stops completely

B、 It can be started after the motor stops

C、 Only after the motor stops completely

32、【 Single topic selection 】 An electric energy meter measures ( ) Instruments used .（  C  ）

A、 electric current

B、 voltage

C、 electric energy

33、【 Single topic selection 】 The work ticket used for the written basis of electrical operation shall be in duplicate ( ) Share .（  A  ）

A、2

B、3

C、4

34、【 Single topic selection 】 In the use of multi-stage fuse protection , The rated melt current of the later stage is higher than that of the previous stage , The purpose is to prevent the fuse from being blown beyond the grade ( ).（  C  ）

A、 Troubleshooting is difficult

B、 Reduce the scope of power failure

C、 Expand the scope of power failure

35、【 Single topic selection 】 The speed of a four pole motor is 1440r/min, Then the slip rate of this motor is ( )%.（  B  ）

A、2

B、4

C、6

36、【 Single topic selection 】 Check the insulation of each winding of the motor , The requirement is ： Each motor 1kV Working voltage , Insulation resistance ( ).（  B  ）

A、 Less than 0.5MΩ

B、 Greater than or equal to 1MΩ

C、 be equal to 0.5MΩ

37、【 Single topic selection 】 Check the insulation of each winding of the motor , If the measured insulation resistance is zero , When no obvious burning is found , Then it can be dried , At this time ( ) Power on and run .（  B  ）

A、 allow

B、 Don't allow

C、 After drying, you can

38、【 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

39、【 Single topic selection 】 The luminous voltage of high voltage electroscope shall not be higher than the rated voltage ( )%.（  A  ）

A、25

B、50

C、75

40、【 Judgment questions 】 After the power failure , The motor stops , When the grid calls again , The operation mode in which the motor can start by itself is called voltage loss protection .（  ×  ）

41、【 Judgment questions 】 Use red in the safety color code to indicate that it is forbidden to 、 Stop or fire fighting .（  √  ）

42、【 Judgment questions 】 The residual operating current is less than or equal to 0.3A Of RCD It belongs to high sensitivity RCD.（  ×  ）

43、【 Judgment questions 】 The positive direction of electromotive force is defined as from low potential to high potential , Therefore, the positive pole of the voltmeter should be connected to the negative pole of the power supply 、 The negative pole of the voltmeter is connected to the positive pole of the power supply .（  ×  ）

44、【 Judgment questions 】 The current carrying conductor must be affected by the magnetic field force in the magnetic field .（  ×  ）

45、【 Judgment questions 】 To prevent electrical sparks , Electric arc, etc. ignite explosives , Explosion proof electrical equipment with explosion-proof electrical grade and temperature group suitable for the environment shall be selected .（  √  ）

46、【 Judgment questions 】 Safety and reliability are the basic requirements for any switching appliance .（  √  ）

47、【 Judgment questions 】 The action value and release value of the intermediate relay can be adjusted .（  ×  ）

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

49、【 Judgment questions 】 After the power failure of the line connected to the shunt capacitor , The capacitor bank must be disconnected .（  √  ）

50、【 Judgment questions 】 Emergency lighting is not allowed to share the same line with other lighting .（  √  ）

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

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

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

54、【 Judgment questions 】 Electricity inspection is one of the technical measures to ensure the safety of electrical operation .（  √  ）

55、【 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.（  √  ）

56、【 Judgment questions 】 When working with bamboo ladders , The ladder is placed on the ground to 50° It's better to be left and right .（  ×  ）

57、【 Judgment questions 】 Protective neutral connection is applicable to the distribution system with neutral point directly grounded .（  √  ）

58、【 Judgment questions 】TN-C-S The system is a system in which the protection zero line and working zero line of the trunk line are completely shared .（  ×  ）

59、【 Judgment questions 】 Thunderstorm weather , Don't repair electrical wiring at home even indoors 、 switch 、 Socket, etc . If you have to repair it, turn off the main power switch at home .（  ×  ）

60、【 Judgment questions 】 If the capacitor is running , Check that the temperature is too high , Ventilation should be strengthened .（  ×  ）

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

62、【 Judgment questions 】 Outdoor capacitors are generally installed on bench .（  √  ）

63、【 Judgment questions 】 In the safety work regulations of the power industry , Safety technical measures include work ticket system 、 Work permit system 、 Work guardianship system 、 Work interruption transfer and termination system .（  ×  ）

64、【 Judgment questions 】 In the magnetic circuit , When the magnetoresistance is constant , The magnetomotive force is proportional to the inverse magnetic flux .（  ×  ）

65、【 Judgment questions 】《 Safe production method 》 said “ The Department responsible for the supervision and management of work safety ” It refers to the work safety supervision and administration departments at all levels .（  ×  ）

66、【 Judgment questions 】 In case of live fire extinguishing , If the spray gun is used, the nozzle of the water gun should be grounded. , And wear insulating boots and insulating gloves , Only then can the fire extinguishing operation be carried out .（  √  ）

67、【 Judgment questions 】 When checking the capacitor , Just check whether the voltage meets the requirements .（  ×  ）

68、【 Judgment questions 】 Use a multimeter to measure the resistance , Ohmic zero adjustment shall be carried out every time the ohmic gear is changed .（  √  ）

69、【 Judgment questions 】 The electronic ballast of the fluorescent lamp can make the fluorescent lamp obtain high-frequency alternating current .（  √  ）

70、【 Judgment questions 】 When the fluorescent lamp is on , The ballast has the function of reducing voltage and limiting current .（  √  ）

71、【 Judgment questions 】 The electroscope must be confirmed to be in good condition before use .（  √  ）

72、【 Judgment questions 】 Incandescent lamp belongs to thermal radiation light source .（  √  ）

73、【 Judgment questions 】 Making and breaking capacity of AC contactor , It is related to the structure of contactor and arc extinguishing mode .（  √  ）

74、【 Judgment questions 】 When the bulb is turned on , There is current on the zero line , The human body can no longer touch the zero line .（  ×  ）

75、【 Judgment questions 】 In addition to the independent lightning rod , On the premise that the grounding resistance meets the requirements , The lightning protection grounding device can be shared with other grounding devices .（  √  ）

76、【 Judgment questions 】 The delay time of electric time relay is not affected by the fluctuation of power supply voltage and the change of ambient temperature .（  √  ）

77、【 Judgment questions 】 The electrical symbol of electrolytic capacitor is shown in the figure .

（  √  ）

78、【 Judgment questions 】 When the motor is running, it makes a dull sound, which is the sound of the motor in normal operation .（  ×  ）

79、【 Judgment questions 】 The electrical symbol of the composite button is

（  √  ）

80、【 Judgment questions 】 In order to ensure that the voltage of the working personnel and the grounding wire of the equipment has been accidentally connected in case of power failure . by rule , The ground wire must be of cross-sectional area 25m㎡ The above bare copper flexible wire is made of .（）（  √  ）

81、【 Judgment questions 】 After the power failure , The motor stops , When the grid calls again , The operation mode in which the motor can start by itself is called voltage loss protection .（）（  ×  ）

82、【 Judgment questions 】 General purpose relay can replace coils of different properties , So it can be made into various relays .（  √  ）

83、【 Judgment questions 】 The rubber case switch is not suitable for direct control 5.5kW Above AC motors .（  √  ）

84、【 Judgment questions 】 The high voltage and dazzling light generated by lightning can cause damage to electrical installations and buildings and other facilities , Damage to power facilities or power lines may lead to large-scale blackouts .（）（  ×  ）

85、【 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.（）（  √  ）

86、【 Judgment questions 】 In case of fire on high-voltage line , Insulation tools with corresponding insulation grade shall be used , Quickly open the disconnector and cut off the power supply , Choose carbon dioxide or dry powder fire extinguisher to put out the fire .（  ×  ）

87、【 Judgment questions 】 When using electrical equipment , Because the conductor section is too small , When the current is large, it will also cause fire due to excessive heating .（  √  ）

88、【 Judgment questions 】 The smaller the internal resistance of the ammeter, the better .（  √  ）

89、【 Judgment questions 】 The withstand voltage grade of low-voltage insulating materials is generally 500V.（  √  ）

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

91、【 Judgment questions 】 The risk of two-phase electric shock is smaller than that of single-phase electric shock .（  ×  ）

92、【 Judgment questions 】 Incandescent lamps shall be used for lighting in places with frequent switches .（  √  ）

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

94、【 Judgment questions 】 Electrician pliers 、 Electrician knife 、 Screwdriver is a basic tool commonly used by electricians .（  √  ）

95、【 Judgment questions 】 Fuses are in all circuits , Can play an overload protection .（  ×  ）

96、【 Judgment questions 】 According to the statistics of some provinces and cities , Electric shock accidents in rural areas are less than those in urban areas .（  ×  ）

97、【 Judgment questions 】 The rated current of the melt shall not be greater than the rated current of the fuse .（  √  ）

98、【 Judgment questions 】 In power supply and distribution system and equipment automatic system , Knife switches are usually used for power isolation .（  √  ）

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

100、【 Judgment questions 】 Electrician operation is divided into high-voltage electrician and low-voltage electrician .（  ×  ）

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