tory burch outlets Summary of the basic knowledge

[omem916678]

1. Electrical equipment should be grounded following the exposed conductive parts
(1) anti-shock ground insulation of electrical equipment to prevent damage or leakage current, make the normally uncharged charged exposed conductive parts which cause electric shock,alife high, the ground exposed conductive parts of equipment, called ground against electric shock . The ground can also limit the inrush current or low voltage lines and equipment due to high pressure line caused by fleeing into the high voltage; when generating electrical failure, is conducive to over-current protective devices to shut off the power. This ground is narrow sense of (2) mine ground to guide people to the land of lightning, the lightning current to prevent electrical shock or personal property damage. (3) anti-static grounding the static charge into the earth and prevent the accumulation of static electricity on the human body and equipment hazard. Particular, the current integrated circuits used in electronic equipment a lot, and produce integrated circuits susceptible to electrostatic breakdown, grounded to prevent damage to integrated circuits. (4) anti-electric erosion as a ground for buried metallic sacrificial anode or cathode, to prevent the cables, metal pipes are being subjected to electrical erosion.
layout of grounding its argument type can be divided into external and loop-type ground electrode ground electrode. If its shape, there are tube-shaped,tory burch outlets, with ring-shaped, and several basic forms. If its structure, there are natural and artificial grounding of grounding points. Used as the nature of the earth are: up and down the metal water pipe; a reliable connection with the earth, buildings and structures of the metal structure; laying on the ground while the number of not less than two and laying the cables underground metal foreskin all Metal pipes. However, flammable or combustible liquid and gas pipeline explosion excluded. Used as artificial grounding, and surge with steel, angle steel, flat steel and round steel and other steel products. If the soil with chemical corrosion, should be made of galvanized steel or copper above the access of several his pole. Grounding diagram as shown in Figure 25.
(c) of the mobile and automotive generator
external conductive parts where possible shock hazard should be grounded, usually below ground parts: (l) in or on buildings may be charged a large area of ​​the metal structure may come into contact with people, then should be grounded in order to improve their safety; (2) electrically operated crane rail and truss; (3) a lift frame with wire group; (4) to enhance the metal elevator rope or cable, such as have been connected with the conductive body lift pathway may be ungrounded; (5) outside the substation or transformer room more than 750V line voltage electrical equipment around the metal partitions, metal cover metal bar envelope, and the like; (6), mobile home or coach The exposed metal parts, including mobile homes in the metal structure, coaches metal frame should be grounded.
subject to all of the following can be installed in the vehicle under generator-powered systems on the vehicle frame as the grounding of the system. (1) the generator frame ground connection to the vehicle frame; (2) generators installed in the vehicle only to the equipment and (or) through the generators installed in the vehicle or the jack on the cord and plug connected equipment power supply; (3) exposed conductive parts of equipment and socket ground terminal connected to the generator rack.
when the generator is a separate system, connected to the generator should be neutral on the rack.
(1) in non-conducting locations, such as wood, asphalt and other undesirable conductive ground and wall insulation of electrical equipment, when the two met, (a) 4. (3) non-conductive areas of the request; ( 2) in a dry place, the following rated voltage of 50V, 120V DC rated voltage on electrical equipment or exposed conductive parts of electrical installations, but excluding explosion danger; (3) installed in the switchboard, control panels and electrical equipment The electrical measuring instruments, relays and other low-voltage electrical appliances such as the shell, and when damage occurs when the insulation, the supporting material will not cause dangerous voltage insulators and other metal base; (4) installed in a grounded metal structure on the electrical contact with good equipment, such as the casing base and so on, but other than explosion danger; (5) Rated voltage 220V and below the battery room of the stent; (6) and the grounded base of a reliable electrical contact to ask motors and electrical appliances exposed conductive parts, but except for explosion danger.
2. Functional ground

(d) electrical equipment
(a) of the DC system
2. Car Generator
1. Protective earth
necessary arc suppression coil can be grounded or resistance. But for mobile equipment used in 1 ~ 10kV AC system should be grounded.
meet the following conditions can be used as an exception,tory burch sample sale, not ground: (1) dedicated to the smelting, refining, heating or similar industrial electric-powered electrical systems; (2) speed transmission designed for industrial power supply rectifier separate transmission; (3) a separate power transmission system by the transformer, the transformer primary side rated voltage less than 1000V dedicated control system; its control power supply continuity of power supply, the control system is equipped with a ground detector and ensure that only full-time staff to monitor and repair.
1. Less than 50V AC line
2.50 ~ 1000V AC system
1. Portable generator
DC two-wire power distribution system should be grounded. However, do not ground the following: detection with ground and in the limited space, only to the supply of industrial equipment systems; line voltage is equal to or less than 50V,asics gt 2150 mens 灰太狼与红太狼经典语录 如许幸福的一对狼！, or higher than 300V, the insulation used on the system; communication system by a grounded power supply of DC rectifier system equipment; maximum current at 0.03A DC Fire and below the signal line.
(b) of the communication system
2. The following electrical equipment exposed conductive parts do not ground
three-wire DC power supply system should be directly grounded neutral.

2. Three-wire DC system
3. Neutral connection
(b) the classification of ground in the form
3. l ~ 10kV AC system
generally not grounded, but one who has any of the following should be grounded; (1) by the transformer, the transformer of the power system voltage to ground exceeds 150V; (2) by the transformer, the transformer power supply system is not grounded; (3) to take isolation transformer should not be grounded, but the core must be grounded; (4) installation of overhead lines outside the building.
(1) work on a power system operation in order to ensure, to prevent system oscillation. To ensure the reliability of relay protection in power system grounding in appropriate places, exchange is generally neutral, generally mid-point of DC, in the electronic equipment system, called electronic equipment outside the system than AC and DC grounding for the Power ground. (2) In order to ensure a stable logic ground reference potential, the electronic equipment in the appropriate metal as a Often the logic of the system ground and other analog signals referred to as the DC to the ground. (3) shield grounding into the earth to electrical interference, external electromagnetic interference suppression effect on the electronic equipment can also reduce the interference generated by electronic equipment, other electronic devices. (4) signal ground in order to ensure a stable reference potential signal and set up the ground, such as detection of ground leakage current, impedance measurement bridge and the corona discharge and other electrical parameters measurement loss measurement ground.
rules
1, fabrication and installation of grounding to the calculated by 2.5m, if the design of the cap, the cap amount calculated by the workpiece.
2,四十句短语淘尽做人精华, grounding bus laying, according to the design length Grounding busbar, lightning protection installation according to extend the line in meters, the length of the construction design according to the provisions of the horizontal and vertical length of 3.9% plus an additional amount of length (including turning, up and down, avoid obstacles around,discount the north face 不开心时来看看, take the joint share of length) calculated , time-consuming and should be the other main material calculated to increase the loss rate requirements.
3, grounding jumper to framework need to be grounded, each Vice-frame press
4, lightning rod manufacture, installation, in order to Length, height, according to the number of design requirements. Manufacture lightning rod should be independent of the implementation of the
5, a small long needle semiconductor lightning eliminator installations to Complete sets of equipment factory plant itself is available.
6, use of reinforcement for the building ground deflectors installed to When pro rata adjustment.
7, disconnect clamp fabrication and installation of the sets of calculations.
8, high-rise buildings the roof of the mine grounding device should perform the
9, the laying of the grading rings to When pro rata adjustment. Length of the pressure according to the design needs to be grounded are the length of ring beam center line to extend in meters.
10, steel, aluminum windows, ground to calculation.
11, columns and ring beam reinforcement connection to If the ring beam welding steel reinforcement and more than two, the proportional adjustment, the pillars need to be connected and ring beam reinforcement bars
12, Zuji's laid to
13,orla kiely handbags, grounding debugging as follows:
(1) Determination of Grounding Resistance. General power plant or substation with a body of the mother network, according to a system computation; from the factory into the home network and home network is not connected to an independent grounding grid, the other by a system of calculation, although at the end of the grounding grid will be linked However, their grounding grid should be calculated, not as a network of ground grid should be test specific circumstances.
(2) Determination of lightning rod grounding resistance. Each rod has a separate ground grid (including the independent lightning rod, lightning rod chimneys, etc.), according to a set of calculations.
(3) independent of the grounding device calculated by group. Modulator such as a pillar on the pressure to have an independent grounding device, ie a set of calculations.



Calculation of lightning protection and grounding devices

(a) the role of ground classification
generally divided into protective earth and functional grounding of two;
1 electrical drawings, including the classification of power distribution engineering drawings, power engineering construction drawings, lighting construction plans, construction plans Lightning Protection, weak construction plans, construction drawings for overhead lines.
2 electrical drawings which consists of drawings directory; design specifications; system diagram; plan; large drawing; schematic diagram; equipment and materials lists.
3 text Marks electrical lines a-b (c × d) e-f. a line number or line that uses symbols, b, said wire models, c indicated that the number of wires root, d, said conductor cross-section, e symbols and wiring methods that lead to wear tube diameter, f said the laying of part of symbols.
4 lamps installed Tagging a-b (c × d × L) / e-f. said a number of lamps, b said lamp type or number, c indicated that the number of light fixtures, d, said light power, L said that type of light source, e said lamp mounting height, f said the lighting installation.
5 power system components include power generation plants, substations boost, high voltage overhead transmission and distribution system of transmission lines, substation step-down, urban high-voltage transmission and distribution system of power distribution lines, high voltage distribution panel by electricity, the user step-down transformer.
6 integral part of electrical engineering with low voltage power distribution cabinets, distribution lines, switch boxes, control switches, load.
7 commonly used in electrical installation works, including galvanized steel pipe, galvanized wire and pipe, wire and plastic pipe, metal hose.
8 electrical installation works including single plastic commonly used in PVC wire and copper wire (BV), double plastic PVC copper wire (BVV), flame retardant plastic PVC copper single core wire (ZR-BV), flame retardant plastic PVC copper wire pairs (ZR-BVV), fire a single plastic PVC copper wire (NH-BV), fire-resistant plastic PVC copper wire pairs (NH -BVV).
9 wire cross section of 1.0mm2, 1.5mm2, 2.5mm2, 4mm2, 6mm2, 10mm2, 16mm2, 25mm2, 35mm2, 50mm2, 70mm2, 95mm2, 120mm2, 150mm2, 185mm2, 240mm2, 300mm2 , 400mm2.
10 electrical installation cables commonly used include ordinary cable (VV), armored cable (VV22), control cable (KVV), flame retardant cable (ZR-VV), flame retardant armor Cable (ZR-VV22), flame retardant control cable (ZR-KVV), fire-resistant cables (NH-VV), fire-resistant control cable (NH-KVV).
11 electrical installation, including cable specifications commonly used in single, dual, three-core, four other core, the national standard four-core (3 +1), non-standard four-core (3 +1), five other core , the national standard five-pin (4 +1), non-standard five-pin (4 +1), the national standard five-pin (3 +2), non-standard five-pin (3 +2).
12 lamps include: incandescent, fluorescent lamps, ceiling lamps, chandeliers, combined lantern, lamp, emergency lights, lights and so on.
13 interior electrical wiring project, including Ming distribution line: line code wiring, slot board wiring, conduit wiring, wiring trough, sheathed cable wiring, cable distribution Gang line. With dark lines: Line tube wiring. Cable lines: direct burial, pipe laying, bridge laying.
14 control electrical switch with knife, steel switch, combination switch, air switch. Protective devices: fuses, leakage protection.
15 building weak systems engineering including antenna cable television systems, telephone communication system, radio sound system, automatic fire alarm and automatic fire extinguishing system, closed circuit television monitoring systems, security systems, integrated cabling system .
16 civil form of low voltage distribution system grounding TN system, TT system, IT system.
17 and TN systems are the most common one, is little direct power system grounded by the electrical equipment exposed conductive part of the protection line and the ground point through the connection. In accordance with the neutral line and protection line combinations can be divided into TN-S system, TN-C system, TN-C-S system.
18 According to China Ray Building, the third of three mine buildings.
19 building lightning protection measures include the installation of lightning rod, lightning protection zone, lightning network, lightning protection cage nets, lightning deflectors, lightning protection and grounding devices.
(1) motors,original mbt shoes, transformers, electrical appliances, hand-held electrical appliances and mobile base and the metal shell; (2) the generator neutral cabinet shell, the generator outlet cabinet shell; (3) electrical equipment transmission; (4) transformer secondary winding; (5) distribution, control, protection of the screen (cabinet, box) and the console such as the metal frame and base metal enclosed switchgear housing; (6 ) Indoor and outside the power distribution unit of the metal frame and reinforced concrete frame and metal cover near the bar with live parts and metal doors; (7) AC and DC power cable terminal box, terminal box, and expander of the metal shell and metal cables protection layer, the threading of the pipe can be touched, the laying of cables of the metal trunking, cable tray; (8) Metal exposed conductive parts of lighting; (9) in non-residential asphalt ground, not ground, arc suppression coil resistance grounding system, grounding and lightning protection cable and overhead power lines without the metal tower and reinforced concrete tower, with lightning overhead line tower lines; (10) installed in the power line towers on the switchgear, capacitors and other electrical equipment exposed conductive parts and support; (11) metal armored sheath of control cable, non-armored or nonmetallic sheathed cable 1 ~ 2 idle cores; (12), metal enclosed bus; (13) Box substation of the metal box.
under the following conditions do not require the mobile generator frame ground, the rack can be used as generator power system grounding, the generator only to the condition that the equipment installed in the generator and (or) generation jack on the machine cord and plug connected equipment supply, and the exposed conductive parts of equipment and the ground terminal on the socket connected to the generator rack.

laying of earthing electrical equipment than not laid ground after the course, the unit has to be much safer. However, the arrangement of the grounding device if it is a single ground electrode or ground electrode of introduced type, then the potential distribution is uneven, the body still can not help but be subject to the risk of electric shock. In addition, the single ground electrode or ground electrode of introduced type of reliability is relatively poor. We know from Figure 25, external lead-type grounding the grounding line is connected with the indoor only rely on two lines. If damage occurs to these two lines, the entire ground and grounding lines to cut off. Of course, the injury occurred while the two lines is relatively small. In order to eliminate a single ground electrode or ground electrode outside the cited shortcomings of style, we can lay loop-type ground electrode, as shown in Figure 26 (a). Circle-style grounding potential distribution is very uniform. Human touch voltage Ut and step voltage Uk is relatively small. But the ground is still very uneven distribution of the external potential, the step voltage is still very high, as shown in Figure 26 (b). To avoid this disadvantage can be outside the laying of loop-type ground electrode ground electrode not connected to some flat relationship. This potential distribution outside the grounding to Figure 26 (c) shows the flat down. Therefore, in all cases, priority should be given by loop-type grounding. Only in the use of loop-type grounding more difficult or cost only when lead type with external grounding.

3. External conductive parts
1. Two-wire DC system