This topic is low-voltage electrical work test database and simulation test answer (revised edition in 2020). All the contents are summed up as the test center of low-voltage electrical work test and the main knowledge points that students must master.
1. True or false The absorption ratio of large-capacity equipment is the ratio of insulation resistance (60s) during measurement to insulation resistance (15s) during measurement. (? √? )
2. After the leakage switch trips, it is allowed to check the line by sending power after shunt power failure. (? √? )
3. The specification of multi-purpose screwdriver is expressed by its full length (handle plus rotating rod). (? √? )
4. Judging whether it is true or not When measuring the no-load current of the motor with a clamp meter, you can directly measure it with a small current file. (? ×? )
5. Judging whether it is true or false For the motor with rotor winding, an external resistor is connected in series in the rotor circuit to start, and the resistance value gradually decreases with the increase of motor speed, and finally it is removed, which is called rotor series resistance start. (? √? )
6. True or false: The frequency on the nameplate of the AC motor is the frequency of the AC power used by the motor. (? √? )
7. The judgment has the right to ensure the safety of the zero line, and the zero line of three-phase four-wire must be equipped with a fuse. (? ×? )
8. When a single conductor with a small cross-sectional area is connected flat, splicing method can be adopted. (? √? )
9, true and false distribution equipment should have perfect shielding protection device. (? √? )
10, and the operation certificate for special operations shall be reviewed once every 1 year by the assessment and certification department. (? ×? )
4 1, the value of AC voltage and current indicated by general appliances or instruments is (). (? b？ )
A. Maximum value
B, effective value
C, average value
42, multiple-choice questions in the distribution system of civil buildings, generally use () circuit breaker. (? c？ )
I. Frame types
B, electric type
C, leakage protection
43, multiple-choice questions According to the line voltage level and user objects, power lines can be divided into distribution lines and () lines. (? c？ )
I. Power
B, lighting
C, power transmission
44, multiple-choice questions have higher requirements for color difference, and () should be adopted. (? b？ )
First, colored lights
B, incandescent lamp
C, violet light
45, multiple-choice questions The resistance in the human body is about () ω. (? c？ )
200 pounds
300 pounds
500 pounds
46. The rated working voltage of multi-choice AC contactors refers to the voltage that can ensure the normal operation of electrical appliances under specified conditions. (? b？ )
A, the lowest
B, the highest
C, average
47, multiple-choice questions when using multilevel fuse protection, the rated current of the fuse at the next higher level is greater than the previous level, the purpose is to prevent the fuse from blowing and (). (? c？ )
First, troubleshooting difficulties
B, narrow the scope of power outage
C, expand the scope of power outages
48, multiple-choice questions in the general lighting circuit without electricity is based on (). (? b？ )
A, measure with a shaking table
B, check the electricity with an electric pen
C, use ammeter to measure
49, multiple ac 10kV bus voltage refers to the ac three-phase three-wire system (). (? Answer? )
I. Line voltage
B phase voltage
C, line voltage
50, the insulation strength of multi-choice wire joint should be the original wire insulation strength (). (? b？ )
First, greater than
B is equal to
C, less than
The above is the question bank type of low-voltage electrician operation examination.