1. When the combined switch is selected as the direct control motor, the rated current is required to be 2 or 3 times the rated current of the motor. Correct Answer: True.
2. The text symbol of the fuse is fu. (1.0 points) Correct Answer: True.
3. At present, the rated current of the contactor produced in China is generally greater than or equal to 630A. (1.0 points) Correct Answer: False.
4. Automatic frequency adjustment and compensation is a function of thermal relay. (1.0 points) Correct Answer: False.
5. The circuit breaker can be divided into frame type and plastic shell type. (1.0 points) Correct Answer: True.
6. The action value and release value of the intermediate relay can be adjusted. (1.0 points) Correct Answer: False.
7. The low-voltage circuit breaker is an important control and protection electrical appliance, and the circuit breaker is equipped with an arc extinguishing device, so it can safely close and open the load. (1.0 points) Correct Answer: True.
8. The text symbol of the time relay is km. (1.0 points) Correct Answer: False.
9. The combination switch can directly start the motor below 5kw. (1.0 points) Correct Answer: True.
10. Safety and reliability are the basic requirements for any switching electrical appliances. (1.0 points) Correct Answer: True.
11. After the power failure of the line connected to the shunt capacitor, the capacitor bank must be disconnected. (1.0 points) Correct Answer: True.
12. The method of discharging the capacitor is to connect the two ends with wires. (1.0 points) Correct Answer: False.
13. When checking the capacitor, just check whether the voltage meets the requirements. (1.0 points) Correct answer: False The insulation resistance of valve-type arresters operating below kv should be measured once a year. (1.0 points) Correct Answer: False.
15. Lightning can be divided into two types: direct lightning and induction lightning according to its propagation mode. (1.0 points) Correct Answer: False.
16. Thunder and lightning can be discharged through other charged bodies or directly on the human body, causing great damage to the human body until death. (1.0 points) Correct Answer: True.
17. The rated operating current of RCD refers to the maximum current that can make RCD operate. (1.0 points) Correct Answer: False.
18. The protection zero connection is suitable for the distribution system where the neutral point is directly grounded. (1.0 points) Correct Answer: True.
19. The neutral wire after RCD can be grounded. (1.0 points) Correct Answer: False.
20. The substation and distribution equipment should have a perfect screen protection device. (1.0 points) Correct Answer: True.
21. The grounding wire is an important tool to ensure the staff when the voltage unexpectedly occurs on the equipment and lines that have been cut off. According to the regulations, the grounding wire must be made of bare copper soft wire with a cross-sectional area of more than 25m. (1.0 points) Correct Answer: True.
22. The fence is a screen protection of the equipment installed to prevent the staff from inadvertently touching the part of the live equipment, which is divided into two types: temporary fence and permanent fence. (1.0 points) Correct Answer: True.
23. Use green in the safety color scale to indicate safety, pass, allow, and work. (1.0 points) Correct Answer: True.
The current at 40Hz is the most dangerous. (1.0 points) Correct Answer: False.
25. An electric shock accident is an accident caused by electrical energy acting on the human body in the form of an electric current. (1.0 points) Correct Answer: True.
26. Electric shock is divided into electric shock and electric injury. (1.0 points) Correct Answer: True.
27. In order to ensure the safety of the zero line, the zero line of the three-phase four-wire must be equipped with a fuse. (1.0 points) Correct Answer: False.
28. The yellow and green two-color wire can only be used for the protection wire. (1.0 points) Correct Answer: True.
29. In China, ultra-high voltage transmission lines are basically laid overhead. (1.0 points) Correct Answer: True.
30. For safety, high-voltage lines usually use insulated wires. (1.0 points) Correct Answer: False.
31. Compared with water and metal, water has better conductivity. (1.0 points) Correct Answer: False.
32. Attention must be paid to anti-corrosion measures when connecting wires. (1.0 points) Correct Answer: True.
33. Insulating material refers to a material that is absolutely non-conductive. (1.0 points) Correct Answer: False.
34. The slip rate of the asynchronous motor is the ratio of the speed of the rotating magnetic field to the speed of the motor to the speed of the rotating magnetic field. (1.0 points) Correct Answer: True.
35. A current is formed in the rotor conductor of a three-phase asynchronous motor, and the direction of the current can be determined by the right-hand rule. (1.0 points) Correct Answer: True.
36. After the motor is overhauled, after passing the inspection, the motor can be tested for no-load test and short circuit. (1.0 points) Correct Answer: True.
37. For the inspection of the lubrication of the motor bearing, the motor shaft can be turned on to see if it rotates flexibly and whether there is any abnormal sound. (1.0 points) Correct Answer: False.
38. The electrical control system diagram includes an electrical schematic diagram and an electrical installation diagram. (1.0 points) Correct Answer: True.
39. All components in the electrical schematic diagram are drawn according to the state when there is no energized state or no external force (10 points) Correct Answer: True.
40. Energy consumption brakingThis method converts the kinetic energy of the rotor into electrical energy and consumes it on the resistance of the rotor circuit. (1.0 points) Correct Answer: True.
41. The specifications of the multi-purpose screw screw are expressed by its full length (handle plus rotary rod). (1.0 points) Correct Answer: True.
42. Wire stripper is a special tool used to exploit the surface insulation layer of the head of a small wire. (1.0 points) Correct Answer: True.
43. Mobile electrical equipment can be used with reference to the relevant requirements of hand-held power tools. (1.0 points) Correct Answer: True.
44. When the lamp does not reach the minimum height, the voltage below 24V should be used. (1.0 points) Correct Answer: False.
45. The installation height of the socket in children's activity places such as kindergartens and primary schools should not be less than 18m。(1.0 points) Correct Answer: True.
46. The electroscope must be confirmed to be good before use. (1.0 points) Correct Answer: True.
47. Incandescent lamps should be used for lighting in places with frequent switches. (1.0 points) Correct Answer: True.
48. The voltage of the high-pressure mercury lamp is relatively high, so it is called a high-pressure mercury lamp. (1.0 points) Correct Answer: False.
49. When checking with an electric pen, the electric pen glows brightly, indicating that there must be electricity in the line. (1.0 points) Correct Answer: False.
50. The low-voltage electroscope can detect the voltage below 500V. (1.0 points) Correct Answer: False.
51. When an electrical fire occurs, if the power supply cannot be cut off, the fire can only be extinguished with electricity, and dry powder or carbon dioxide fire extinguishers should be selected, and water-based fire extinguishers should be reduced as much as possible. (1.0 points) Correct Answer: False.
52. When using electrical equipment, due to the selection of wire cross-section, when the current is large, it will also cause fire due to excessive heating. (1.0 points) Correct Answer: True.
53. In places with high fire hazards, portable and mobile electrical equipment should be used as little or as little as possible. (1.0 points) Correct Answer: True.
54. Electricians and special operations personnel shall have a high school education or equivalent to high school or above. (1.0 points) Correct Answer: False.
55. A person with Meniere's disease is not allowed to engage in electrical work. (1.0 points) Correct Answer: True.
56. Electricians should do a good job of monitoring the operation of electricity users in special places. (1.0 points) Correct Answer: True.
57. Apparent power is reactive power plus active power. (1.0 points) Correct Answer: False.
58. The current-carrying conductor must be affected by the magnetic field force in the magnetic field. (1.0 points) Correct Answer: False.
59. An object with conductivity between a conductor and an insulator is called a semiconductor. (1.0 points) Correct Answer: True.
60. The frequency of sinusoidal alternating current in China is 50Hz. (1.0 points) Correct Answer: True.
2 pp. 43.
61. Kirchhoff's first law is the nodal current law, which is used to prove the relationship between the currents on the circuit. (1.0 points) Correct Answer: True.
62. In a series circuit, the currents are equal everywhere. (1.0 points) Correct Answer: True.
63. In the three-phase AC circuit, when the load is a triangle connection, the phase voltage is equal to the line voltage of the three-phase power supply. (1.0 points) Correct Answer: True.
64. When measuring the idling current of the motor with a clamp meter, it can be directly measured with a small current gear. (1.0 points) Correct Answer: False.
65. To measure the insulation resistance to the ground and the insulation resistance between phases of the motor, a megohmmeter is often used, and a multimeter is not suitable to be used. (1.0 points) correct answer;Wrong.
66. After the multimeter is used, the transfer switch can be placed in any position. (1.0 points) Correct Answer: False.
67. There is no need to cut off the power supply of the equipment under test before using the megohmmeter. (1.0 points) Correct Answer: False.
68. The values measured by AC ammeter and voltmeter are all effective values. (1.0 points) Correct Answer: True.
69. The magnitude of the current is measured with an ammeter, and it is connected in parallel in the circuit when measuring. (1.0 points) Correct Answer: False.
70. The clamp ammeter can be made to measure both AC current and DC current. (1.0 points) Correct Answer: True.