The installation of grounding devices must be coordinated with the construction of building projects. Hidden parts must be completed in conjunction with the relevant units before covering. Installation of exposed ground wires must meet the following requirements:
1. This should be convenient to review. ?
2. The installation location must not interfere with ?.
When using protective earthing, the earthing resistance of the earthing device should not be greater than 4Ω. Artificial grounding bodies can be horizontally laid round steel, flat steel, vertically laid steel tube angle steel, round steel. The number of artificial grounding bodies should not be less than two. When laid vertically, the depth in the ground should not be less than. 2.5m. Two artificial grounding bodies doiwind be placed vertically. The vertical distance between earthing bodies must not be less than 5 m. Where there is no design requirement for the depth of burial of the upper surface of the earthing body, the depth shall not be less than 0.6 m. ?Minimum size of protective wire and grounding body: Generally, the grounding device of artificial grounding body should be made of hot-dip galvanized steel, all made of shaped steel. The diameter of the steel pipe is 40-50mm, wall thickness. is at least 3.5mm, the thickness of the angle steel is at least 4mm and the diameter of the round steel is at least 10mm, the section of flat steel is at least 100 square millimeters and the thickness is at least 4 millimeters; When the shielding wire uses insulated wires, the copper core is not less than 2.5 square millimeters. When the protective wire is the samee quality than the phase wire, the section of the phase wire is less than or equal to 16 square millimeters. The section of the protection wire is not less than the section of the protection wire. phase wire. ?Connect the protective wire to the grounding device: use reliable crimping and soldering methods. When welding is used, the lap welding length of the flat steel should not be less than 2 times the width of the flat steel, and at least three edges should be welded firmly; the lap welding length of round steel should not be less than 6 times; the diameter of the round steel and at least two edges must be welded firmly. When using screw crimping, anti-loosening measures should be taken. Aluminum core wires should not be used as protective wires, and it is strictly prohibited to lay bare aluminum wires directly underground. The lines ofprotection should be inspected frequently and any damage, disconnection, play, dropping, corrosion, etc. must be quickly eliminated. ?When burying the crushed body, the surrounding soil should be sprinkled with a certain amount of salt and then poured with water to ensure good conductivity. In addition, the ground strength should be measured once a year during the warranty period to avoid failure due to excessive ground strength.
What are the consequences of grounding the generator phase wire?
Question 1: What are the approximate resistances of the human body and the earth? The human body has 20,000 to 200,000, but it will be broken down by high-voltage electricity, and it is very small at the moment. Earth serves as the negative pole for all power supplies, regardless of resistance.
Question 2: What is the resistance of the earth? To protect equipment and safetypeople, electrical equipment shells often use protective grounding or protective grounding of the working neutral line in three - four phase wire circuits. It is also necessary for the three-phase unbalanced current to enter the ground smoothly and flow back to the generator end through the earth's unbalanced current to form a loop protective grounding body. must be greater than 1.5 meters. We can say that the resistance of the earth at this depth is 0 ohm (because the earth is below this depth due to the high humidity electrolyte must dissolve with water to form a good conductor, so the the earth resistance is approximately 0). In the phase-zero circuit, the neutral line current enters the earth and is also returned to the generator end. Since people cannot live without electricity, the earth's powerful currents circulateulent below 1.5 meters. These feedback currents are ultimately transmitted to electricity.
Question 3: What is the resistance of the earth? I'm not sure!
Earth is a conductor and the resistance is different when the circuit is connected from two different points.
Question 4: Is the conductive capacity of the earth great? What is the resistance between two points on the earth? First of all, the earth is not a good conductor on the surface? , it seems that the earth's surface is composed of high-strength objects. Yes, but that doesn't stop the earth from becoming a supercapacitor. Usually we use earth or infinity as a potential zero point. charge that you inject into the earth (earth)
Question 5: Earth is a conductor, does it have resistance, and what is the resistance (1): Draw it? following figure according to the point drawing method: (2): D'after the θ-U image, we see that 20℃, 40℃, The voltmeter readings corresponding to the four temperature values of 60℃ and 80℃ are: 20℃-1.83; 40℃-1.08; 60℃-0.62; 80℃-0.42. From the data on the graph, it can be seen that the reading range of the voltmeter is in the “0-3” range. the range "0-3" is therefore selected. (3): According to the circuit diagram: U 0 = U + U R 0, the current through the circuit is I = U R 0R 0, then the thermistor is: R t = UI, combining the above solutions, we obtain: R t = UR 0U 0?U From the image, the voltmeter voltage U=1.83 at 20°C can be read. By replacing the formula above, we obtain: R t=0.36 kΩ; As shown in (2) range "0-3" (3) 0.36 KΩ, R t=UR 0U 0?U
This probably requires a detailed explanation. Go to Hard City and take a look. can.
Can the neutral wire of an 80 kilowatt generator be grounded?
Question 1: If a phase wire is grounded, the voltage de ungrounded phase will increase in low voltage areas. Insulation, insulation is easy to break, resulting in the load of the equipment shell. Since the low voltage three-phase uses protection to connect to zero, the shells of all equipment will be connected to the zero and neutral line of the. the transformer must have voltage and: earth current = 220 / (grounding resistance of the phase line + earthing resistance of the neutral point of the transformer), thus reducing the earthing current by the neutral line. Question 2: The principle of the generator is that the induction coil (conductor) cuts the magnetic field lines and converts the work into induced electromotive force. When the coil forms a closed loop, an induced current is generated and the induced current flows. electrical equipment to carry out the work. If the phase line and neutral line are grounded,that is, among three-phase lines, the potential of the grounded phase line is equal to that of the neutral line. If the generator power remains unchanged, the generator voltage. The other two phase lines will increase and the voltage of the grounded phase line will increase. The work done by intersecting the magnetic field line with the phase line passes through the neutral line and grounding point of the phase line and is directed to earth.
The neutral wire on the 80 kilowatt generator is not the ground wire. The standard 80 kilowatt generator has dedicated ground wires and lightning protection wires. The neutral wire of the 80 kilowatt generator is used in conjunction. with the live wire, which is for output power wiring, as long as you follow the generator instructions and connect the live wire and neutral wire of the appliance through the generator circuit breaker, it can bebe used normally.