English Chinese Línea directa
Wire and Cable Quiz
Publicado:2013-04-24
A single core cable sheath end of the ground in the way Why must install a parallel cable laid along the return wire?
A: The grounded at one end of the metal sheath cable lines, in order to ensure that the induced sheath voltage does not exceed agreed standards, must be installed along a line parallel to the laying of the cable conductor, and the conductor is grounded at both ends, this conductor called back flow lines. When single-phase ground fault, ground fault current can flow back through the return line system central point because the ground current return wire through the magnetic flux generated offset by a sector cable wire grounding current generated by the magnetic flux, thus
Jacket lower short-circuit fault induced voltage.



2, the cable works can be divided into several projects?
Answer:
(1) haul: including engineering construction material from the warehouse to the point of loading and unloading, transport and return empty.
(2) Local projects include: road excavation, tunnel, trench works.
(3) laying works include: laying in the middle head production, lift the cover, pipe, school tide, drawing head production.
(4) both ends of the projects include: support, bridge frame and its underlying production installation, the terminal head production, oil pressure and signaling devices, were kind of electrical function testing.
(5) Cyprus ended engineering: the first production of oil-filled cable plugs only for the fuel tank, automatic drainage and signaling devices installation.
(6) Ground engineering: insulating joints, transposition boxes, protection, grounding tank installation.



3, the acceptance of cable lines which checks should be carried out?
Answer: (a) shall comply with the cable specification designation, arrangement should be clean, no damage, signs complete, accurate, clear;
(2) fixing the cable bending radius, the relevant interval, and single-core power cable metal sheath of the cable should meet the requirements;
(3) cable terminal, intermediate head does not leak oil, securely installed, oil pressure and oil-filled cable meter setting value should meet the requirements;
(4) well grounded;
(5) Cable terminal phase color accurate, brackets and other metal parts paint intact;
(6) trenches and tunnels, the bridge should be no debris, cover complete.



4, the cable line positive sequence impedance measurement process What are the requirements?
A: The conductor AC resistance and inductance of the cable three phase volume and the same is called positive sequence impedance.
Cable line positive sequence impedance can generally be measured directly on the cable tray, measuring generally use a lower voltage, and therefore, need to step-down transformer step down buck a star wiring, capacity is generally 10kVA or more, wide range of voltage regulation, measuring when AC power should be more chaos, in order to ensure measurement when the current reaches delineated requirements, the actual voltage meter readings must be really a voltage cables, preferably close to the test current carrying capacity of the cable long promised
, the meter readings each value, after closing the current three tables simultaneously read the values.



5, according to the "electrical production safety designation" electrical work on the premise that the staff must have a what?
A: Required with the following conditions:
(1) identification of health by doctors, without prejudice to the work of the disease;
(2) have the necessary electrical knowledge, to grasp the nature of their duties and related procedures, technical expertise and safety control technology, and pass the examination;
(3) skillful grasp of electric shock first aid.




6, the cable during transport loading and unloading process should pay attention to what?
Answer: (a) in the transport loading and unloading process, should not be damaged cables and cable tray, cable tray is strictly prohibited pushed directly from the car, the cable should be laid flat like transportation, flat storage.
(2) transport or move cable reels, you must ensure that cable tray firmly cable around tight, oil-filled cables between the tubing to the pressure tank should be fixed, not injury, the pressure tank should be firm, pressure indicator should meet the requirements.



7, the cable fire What measures?
Answer: (a) use of flame-retardant cable;
(2) use of fire in cable trays;
(3) use of fire-resistant coating;
(4) cable tunnel, laminated, etc. set fire wall outlet, fire dampers;
(5) row hit cable should avoid oil pipeline, explosion doors, or should have to wear a tube or take partial insulation fire protection measures.
8, select the section of power cables where several aspects should be considered?
A: The following aspects should be considered:
(A) long-promised through cable operating current;
(2) Once the heat is not shorted chaos;
(3) the voltage drop on the line can not exceed the agreed scope of work.
9, power cables and drain lines have more hit what strengths?
Answer: (a) reliable operation, such as installed in the underground shelter, subject to external damage is small, less chance of failure, security of supply and will not cause harm to the person;
(2) maintenance workload, without frequent inspection;
(3) no erection tower;
(4) help to improve power factor.

Dingzun credo:Para hacer los productos como la vida;
Filosofía Dingzun:Tratar a las personas con sinceridad, calidad Lixin;
Búsqueda Dingzun:La satisfacción del cliente es siempre lo primero;
Dingzun objetivo:Ayudarle a convertirse en la industria de la suprema.
Copyright: Shanghai Dingzun Electric&Cable Co., Ltd.  Tel :021-69177761  Fax 021-69177762  Local sale Mail: sales@sh-dingzun.com
Export office add.: Room 1708-1709, Building 2, Lane 31, Jia Tong Rd, Nan Xiang Town, Shanghai, China
Factory & local sale: No. 136, Chang Xiang Road, Nan Xiang Town Shanghai, China
沪ICP备12044781号-2
我要啦免费统计