Brazing sintered diamond Saw Blade features
1, the diamond edge can be 2/3 of the diamond height, so grinding
Cutting efficiency is high, and is conducive to scouring debris, surface abrasive particles are not easy to cause
Blockage and loss of grinding ability.
2, due to the high edge of diamond, chip tolerance space, diamond and base
The high binding strength between the bodies prevents the diamond from falling off.
3, brazing diamond saw blade is suitable for cutting ceramics, microcrystalline stone, people
Stone, marble, super sharp.
What are the advantages of brazing diamond saw blade
1, high cutting edge rate, cutting efficiency is very high;
2, diamond and matrix chemical combination, in the work is not easy to take off
Fall;
3. High sharpness, straight cutting edge, fast feeding speed and easy feeling;
4, large chip space, surface abrasive is not easy to lose grinding due to blockage
Ability.
If cracks appear on the grinding wheel in the process of use, stop using the grinding wheel immediately and replace the cutting piece with a new one to avoid breaking the cutting piece and injuring others.
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First, the plant distribution map
Second, the plant differentiated surface and equipment damage
1. The factory building is a metal frame structure. It is located in the foothills of the mountain (size: L*W*H60*85*11M). It has a hill height of about 12 meters on the northwest side and is mountainous on both sides. The soil soil is weathered soil plus laminated rock, and the soil resistivity is 3350 ohm•m.
2. There is a tower of about 30M high 220KV high voltage transmission towers on the northwest side of the plant and the southeast hill.
3. When there is no lightning strike near the rainy weather, there are often parts of the plant's electrical equipment, monitoring equipment, network equipment, communications equipment and other damage.
4. Occasionally, during the thunderstorm, we can see that there is a fire at the top of the high-voltage tower, and if there is a lightning strike, some equipment must be damaged.
5, thunderstorm weather When people pass near the northwest tower, the body has a weak feeling of being electrocuted.
6. To ensure the safety of personnel and property in the factory area, Party A urgently proposed to increase the lightning protection of the plant area.
Third, the problem analysis
1. Ground potential counterattack For such field analysis, the transmission line carries high voltage, large current, strong electric field and complex electromagnetic environment during operation. Both electric field interference caused by high voltage, and ground potential interference caused by potential difference when a large current flows through the grounding device.
When a lightning strike or a thunderstorm occurs in the distance, the lightning current flows into the ground to generate a large pressure drop, which raises the ground potential and reversely punctures the electrical equipment in the plant.
The grounding down conductors of the high-voltage power transmission towers on the northwestern side of the plant and the southeastern hills are all laid out along a straight line, and are close to the building. The transient high potential generated during thunderstorms is the main cause of equipment damage.
2. Surge surge voltage generated by lightning: refers to the fact that the output voltage has an RMS value higher than the rated value of 110% in a moment (milliseconds) and lasts for one or several cycles. It is the main culprit of the destruction of electronic equipment.
Transient over-voltage and transient over-voltage, refers to the peak voltage up to 20000V, but the duration of 10 ~ 6s-10 ~ 4s pulse voltage. The main reason for its occurrence and possible damage are similar to high-voltage spikes, which are mainly caused by lightning.
Its main hazards are: the use of advanced electronic devices such as control, monitoring, protection, communications, computer networks, etc., with large-scale integrated circuits as the core components, and other electronic devices composed of large-scale CMOS integrated components. The disadvantage of the weak current capability is that the transient overvoltage not only causes the electronic equipment to malfunction, or causes the electronic equipment to be disturbed, the data is lost, or is temporarily damaged; in severe cases, the breakdown of the components and the burning of the circuit board can be caused. The entire system is paralyzed.
3, equipotential processing equipotential bonding as the IEC standard for the most protection of electrical devices, China's relevant lightning protection also attaches importance to equipotential bonding, equipotential bonding due to all the conductive parts are electrically connected, in the event of electrical failure It can effectively prevent the occurrence of potential difference within the scope of the connection, and has a protective effect on personal safety and the safety of electrical equipment.
After on-site investigation, there was no equipotential bonding between the exposed conductive parts and the metal structures of the various electrical devices in the district.
Fourth, the solution
1. The ground potential counterattack is used to ground the two power towers near the powerhouse, and the original ground wire grid layout is changed to a ring grounding net. A grounding module with a water-absorbing and water-retaining function is used to make a grounding net due to the influence of the soil and soil environment, and two to three annular trenches are excavated for each tower.
Around the factory building, no less than two ring-shaped grounding nets were made to connect the ground nets extending to each building.
Connect the two power tower grounding nets to the ground in the factory area through the flat steel. To reduce the voltage drop when the lightning current flows through the earth.
2. The surge generated by thunder and lightning increases the power supply, control, network, monitoring and other lightning protection equipment matching each technical parameter of the equipment according to the relevant national calibration standards.
3. Equipotential bonding The main steel girders of the metal frame building are welded to the ring ground through the flat steel.
The exposed conductive parts of the metal in the factory building and the metal support are connected to the total equipotential bonding terminal through the PE wire.
Connect all metal doors, windows and cabinets in the building to the total equipotential bonding terminals.
V. Conclusion
After grounding rectification of power towers outside the plant area, increasing the grounding resistance in the plant area to reduce the grounding resistance, increasing the matched surge arresters among the equipments, and increasing the targeted treatment of equipotential measures in the plant area, etc., to the plant area Each system in the system has the functions of equalizing voltage and lightning protection, completely protecting the safety and normal work of personnel and equipment, and at the same time playing a more important role in protecting the lives and property of the country and people. After more than two years of testing, none of the systems experienced any failure.
references:
[1]GB50057-94 (2010 edition) "Lightning Protection Design Code for Buildings"
[2]JGJ/T16-92 "Civil Building Electrical Design Code"
[3]GB50169-92 "Electrical Installation Engineering Grounding Device Construction and Acceptance Specifications"
[4] GBJ233-90 "110-500kv overhead power line construction and acceptance specifications"
Frequent lightning strike causes and treatment methods
With the continuous increase of electricity demand in China, the development of electric power will also develop at a rapid rate. Electric power lines and towers will spread throughout urban and rural areas. The risk of lightning strikes on power equipment in factories and workshops near the poles and times will increase exponentially to better protect and treat electricity. The equipment is protected from lightning damage and protects the lives of the country and people and the property. In this system, the causes of ground potential counterattack, surge, equipotential processing, lightning strike and other damages will be described in detail according to one of the examples.