工厂供电（The factory power supply）.docVIP

工厂供电（The factory power supply） Plant power supply test bank 1. Single item selection (2 points per question, 10 points) : 1. In the distribution design, the maximum average load of __ b. 30min _____ is usually adopted as the basis of selecting electrical appliances or conductors according to heating conditions. 30 min 20 min a. b. c. 60 min d. 90 min Peak current refers to the maximum load current for A single or multiple electric equipment. A. 1 s B. 5 s c. 15 s d. 30 s 3. The active power of the welder refers to the active power of the rated power conversion to the temporary load rate of ___ d. 100%. A. 15% b. 25% c. 50% d. 100% 4. When the number of electrical equipment is small and the capacity of each device is very different, the _____ of the binomial coefficient method is appropriate. A. the binomial coefficient method b. standard method c. need coefficient D. Ohm method 5. The light source is enclosed by a transparent cover in the structural features of the lighting of the factory, and the air inside and outside cannot be connected to. A. open type b. close type c. airtight type d. explosion-proof type 2. Fill in the blanks (1 point each time, 20 points) : 1. The basic requirements for power supply in factories are (safety, reliability, quality and economy) 2. The heavy load in the first class load shall be equipped with (emergency power supply) except for (two) independent power supply, and other load access shall be strictly prohibited. The basic measure of power quality is (voltage) and (frequency). The industrial frequency used in China is (50) HZ. 4. Various high and low voltage switches belong to (a) secondary equipment. The falling type fuse belongs to the (non-confined) fuse. 6. All the lightning protection devices must be connected with the (grounding device). 7. The basic requirements of the relay protection device are: (selective), (quick-acting), (agility), and reliability. 8. (vacuum) circuit breaker is suitable for frequent operation and high s