01
AC contactor rated working voltage refers to the ( ) voltage that can ensure the normal operation of the electrical appliance under specified conditions.
A, minimum
B, maximum
C, average
【Answer】B
02
The two basic principles that should be followed in correct selection of electrical appliances are the safety principles and ( ) principles.
A, economic
B, performance
C, function
【Answer】A
03
Highlights are close to the motor overload characteristics, in order to give full play to the ( ) capabilities of the motor.
A, overload
B, control
C, throttling
【Answer】A
04
04
The protection characteristics of fuse are also called ().
A, ampere-second feature
B, arc extinguishing feature
C, time-based
【Answer】A
05
The function of the parallel power capacitor is ().
A, reduce power factor
B, improve power factor
C, maintain current
【Answer】B
06
In order to prevent step voltage from causing harm to people, the minimum distance between the entrances and exits of buildings and sidewalks should not be less than ( ) meters.
A, 3
B, 2.5
C, 4
【Answer】A
07
Anti-static grounding resistance requires no greater than ( )Ω.
A, 10
B, 40
C, 100
【Answer】The re-grounding of other grounding points on the C
08
PE line or PEN line except for working grounding is called ( ) grounding.
A, direct
B, indirect
C, repeat
【Answer】C
09
The use of safety rope should ( ).
A, use high hang low
B, call low hang
C, ensure safety
【Answer】A
10
"Close is prohibited, someone works" sign should be made as ().
A, white text
B, red text
C, green text
【Answer】B
11
When an electrical equipment has a grounding fault, the grounding current flows to the ground through the grounding body. If a person walks around the grounding short circuit point, the electric shock caused by the potential difference between his legs is called ( ) electric shock.
A, single-phase
B, step voltage
C, induction
【Answer】B
12
According to the line voltage level and user object, power lines can be divided into distribution lines and ( ) lines.
A, lighting
B, power
C, power
【Answer】C
13
13
Among the following materials, the best conductive performance is ().
A, aluminum
B, copper
C, iron
【Answer】B
14
The intermediate joint of the wire is used to be hinged, first twist ( ) circles in the middle.
A, 2
B, 1
C, 3
【Answer】C
15
National standard stipulates that all motor with ( ) KW or above are used in triangular connection.
A, 3
B, 4
C, 7.5
【Answer】B
16
Step-down Startup refers to reducing the voltage applied to the motor ( ) winding at startup, and after starting operation, then restore its voltage to the rated voltage to run normally.
A, rotor
B, stator
C, stator and rotor
【Answer】B
17
When the motor runs under the rated working state, the ( ) added to the stator circuit is called the rated voltage.
A, line voltage
B, phase voltage
C, rated voltage
【Answer】A
18
When using wire stripper , you should choose a blade with a diameter of the wire ( ).
A, slightly larger
B, same
C, larger
【Answer】A
19
On each single-phase circuit in the lighting system, the number of lamps and sockets should not exceed ( ) ones.
A, 20
B, 25
C, 30
【Answer】B
20
Conductor connectors are not tightly connected, which will cause joints ().
A, insulated
B, heating
C, non-conductive
【Answer】B
21
Light source belongs to ( ) light source.
A, gas discharge
B, heat radiation
C, bio discharge
【Answer】A
22
When a low-voltage electrical fire occurs, the first thing you should do is ( ).
A, quickly try to cut off the power supply
B, quickly leave the site to report to the leader
C, quickly use dry powder or carbon dioxide fire extinguisher fire extinguisher
【Answer】A
【Answer】A
23
If the special operator fails to undergo special safety operation training and obtains the corresponding qualifications as required and takes up work, the production and operation unit shall be ordered to operate ().
A, correct
B within a time limit, fine
C, suspend production and business rectification
【Answer】A
24
Special operators must be at least ( ) years old.
A, 19
B, 18
C, 20
【Answer】B
25
The total resistance of three resistors with equal resistance values is ( ) times that of the total resistance in parallel.
A, 6
B, 9
C, 3
【Answer】B
26
26
The size of electromagnetic force is ( ).
A, inversely proportional
B, proportional
C, unchanged
【Answer】B
27
monopole semiconductor device is ().
A, diode
B, bipolar diode
C, field effect tube
【Answer】C
28
( ) The instrument consists of a fixed permanent magnet, a rotatable coil , and a shaft, a hairspring, a pointer, a mechanical zeroing mechanism, etc.
A, electromagnetic
B, magnetoelectric
C, induction
【Answer】B
29
When measuring the insulation resistance of the motor coil to the ground when is measured, the "L" and "E" of and the two terminals of should ( ).
A and "E" are connected to the terminals for the motor outgoing, "L" is connected to the motor housing
B, "L" is connected to the terminals for the motor outgoing, "E" is connected to the housing
C of the motor, and there is no regulation.
[Answer] B
30
multimeter is essentially a ( ) instrument with rectifier .
A, electromagnetic
B, magnetoelectric
C, electric
【Answer】B
31
Non-automatic switching appliances rely on ( ) direct operation to perform work.
A, external force (such as manual control)
B, electric
C, induction
【Answer】A
32
low voltage fuse, widely used in low-voltage power supply and distribution systems and control systems, is mainly used for ( ) protection, and sometimes can also be used for overload protection.
A, short-circuit
B, quick-break
C, overcurrent
【Answer】A
33
Current relay is used when it attracts the coil directly or through the current transformer ( ) in the controlled circuit.
A, parallel
B, series
C, series or parallel
【Answer】B
34
In the protection of multi-stage fuses, the rated current of the subsequent stage is greater than that of the previous stage, and the purpose is to prevent the fuse from fuse from fuses overstep and ().
A, reduce the power outage range
B, difficulty in checking
C, expand the power outage range
【Answer】C
35
capacitor should ( ) after the pointer swings when checking with a multimeter.
A, keep it still
B, gradually swing back and forth
C, swing back and forth
【Answer】B
36
Lightning rod is a commonly used lightning rod. When installing, the lightning rod should be equipped with an independent grounding device . If it is in a non-high resistivity area, its grounding resistance should not exceed ( )Ω.
A, 4
B, 2
C, 10
【Answer】C
37
In order to avoid direct lightning strikes in high-voltage substations and distribution stations causing large-scale power outages, generally ( ) can be used to prevent lightning.
A, flash rod
B, valve arrester
C, flash network
【Answer】A
38
For low-voltage distribution network, when the distribution capacity is below 100KW, the grounding resistance of the equipment protection grounding should not exceed ( )Ω.
A, 6
B, 10
C, 4
【Answer】B
39
( ) can be used to operate high-voltage drop fuse , single pole isolating switch and install temporary grounding wires.
A, insulating gloves
B, insulating shoes
C, insulating rod
【Answer】C
40
Before climbing the pole, foot buckle should be ( ).
A, human load impact test
B, human static load test
C, human load tensile test
【Answer】A
41
Usually, under the action of 220V industrial frequency voltage, the resistance of the human body is ( )Ω.
A, 500-1000
B, 800-1600
C, 1000-2000
【Answer】The colors of the C
42
protection wire (grounded or neutral wire) should be used according to the standard ( ).
A, red
B, blue
C, yellow and green two-color
【Answer】C
43
43
Low voltage circuit breaker is also called ().
A, switch
B, main switch
C, automatic air switch
【Answer】C
44
Thermal relay tuning current is ( )% of the motor rated current.
A, 120
B, 100
C, 130
【Answer】B
45
star-triangle step-down start-up is to connect the three-phase windings of the stator to ( ) when starting.
A, triangle
B, star
C, sequential triangle
【Answer】B
46
Apply ( ) to clean the dirt and dust inside the motor.
A, dip gasoline, kerosene, etc. on the cloth, wipe
B, wipe
C, blow with compressed air or wipe
with dry cloth [Answer] C
47
Check the insulation of each winding of the motor. If the insulation resistance is measured to be zero, and when there is no obvious burning, it can be dried. At this time ( ) is powered on and run.
A, allow
B, do not allow
C, after drying,
【Answer】B
【Answer】B
48
Accident lighting generally uses ().
A, fluorescent lamp
B, incandescent lamp
C, high-pressure mercury lamp
【Answer】B
49
screw head threads should be connected to ( ).
A, phase line
B, neutral line
C, ground line
【Answer】B
50
In the circuit, the switch should be controlled ( ).
A, neutral
B, phase
C, ground
【Answer】B
electrical question bank to get
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