When the transformer and the work of the diesel generator neutral grounding, electrical protective earth grounding system work and share weak grounding device, the grounding resistance should be less than 1 euro. Use common grounding, the weak systems should their equipment room, and building insulation grounding stud, with more than 25 mm2 copper cable or wire welded steel pipe made through a separate drop, the foundations of buildings connected with the ground plate. Weak system of general requirements for grounding resistance of less than 4 ohms, should be an independent ground system view often ? Boxu Chile to catch car owner thereupon low ash wood ho chant argon ∮? 0 meters.
3. Sideswipe against mine measures should meet the following requirements:
Height over 30 meters of reinforced concrete structures, steel structures, should take the following anti-swipe mine and equipotential bonding of the protective measures:
(1) steel frame and reinforced concrete should be connected to each other;
(2) should be used within the steel column or reinforced concrete columns reinforced as a lightning protection device deflectors;
(3) should be 30 meters and over the railings on the external walls, doors, windows and other large metal objects and lightning protection device is connected;
(4) vertical laying of metal pipes and metal top and low-end devices to be connected with the mine;
(5) columns and ring beam without the buildings, walls should be laid at intervals of around three out of galvanized round steel ¢ 12 to do the grading rings, a combination of columns and ring beam, the use of steel for the ring beam grading ring. All the building every three vertical metal pipe connected with a grading ring. Grading ring should be connected with the lightning protection device deflectors.
4. Lightning induction of measures, should meet the following requirements:
(1) The protection of metal objects within the building ground, is the main measure lightning induction. Therefore, the building housing the equipment, pipelines, and other major metal frame should be close to receiving the grounding or electrical equipment, lightning protection grounding device
(2) parallel to the laying of pipes, cables metal jacket structure and a long metal object, the spacing is less than 100mm should be used jumper wire, cross-junction spacing should not exceed 30m; crossing clearance less than 100mm, the should be across the intersection.
5. Lightning invasion wave of measures, should meet the following requirements:
(1) line of low voltage lines should be buried with the cable directly into the home end of the cable jacket or the protection of metal pipe on the device receiving the lightning protection and grounding; if connected to overhead lines should be changed into the household 50m cable, cable for connection at arrester should be installed, and with the cable metal sheath, steel and iron insulator feet, fittings, etc. together, the impulse grounding resistance should not exceed 10 ohms. If overhead wires are used, the arrester should be installed into office.
(2) overhead and underground metal pipes, should be in and out of buildings and lightning protection grounding device connected at.
Fixed on the building of holiday lights, aviation obstruction lights and other electrical equipment of the line, should be based on the importance of building the mine to take corresponding measures invasive radio waves:
a. no metal or electrical equipment protection network should cover the protection of air terminals within;
b. The line leads from the distribution box should wear steel. Ends of the pipe is connected with metal distribution box; the other side of the metal casing and electrical equipment, protective cover is connected, and lightning protection devices connected to your nearest roof. Pipe should be located off the middle of the jumper.
Third, and experience
This internship, I learned that the size of the plant level, the production process and the production of some conventional products, the study design in the future I believe there will be more help.
In addition, I feel that through this internship for me after the choice of electrical equipment, lighting, power, systems, lightning protection and grounding aspects of the design will be very helpful thank the school and the teacher gave us this Gui internship opportunities.
范文二
It is my honor to stand here today. first of all, i want to thank our dean mrs. li to give me this chance to deliver a speech to you. thanks.
This is a speech about practice report, in the first place i want to share with you about my work experience.
In the first summer vacation in the college, i changed 3 part-time jobs. the first one was waiter; the second one was teaching assistant in talking time language village (ttlv); the third one was interpreter in a highway service station. maybe you will ask me how can you get 3 part-time jobs and why do you want to change it? actually this is a good question. here are 3 reasons: first i want to speak english，second i want to practice english, third i want to use english. this was also the main reason i quitted the first one job waiter. then i searched ttlv online and i attended the interview and passed the teaching test. everything seems went smoothly, i started to work there in a few days later. i was a teaching assistant there, i was in charge of 8 students in my class and i assisted the foreign teacher to interpret for the students during the class. i work there for 20 days then i left because of olympic games in china. so i lost, that seems god always take good care of me, one of my supervisor in ttlv recommended a good job to me after i lost a few days, that was my third job in that vacation. i was an interpreter and i was in charge of communication with foreign friends there. i worked there for 30 days, i got 1500rmb which was my first time to earn so much money by myself in my lifetime.
