Copper core fire-resistant control cable NHKVV-4 * 2.5

Description :

　　A communication cable is a communication line consisting of multiple insulated wires or conductors that form a core and have a sealed sheath on the outside. Some also have an outer protective layer outside the sheath. There are various laying methods such as overhead, direct burial, pipeline, and underwater. Divided by structure into symmetrical, coaxial, and composite cables; Divided by function into field and permanent cables (underground and submarine cables). Communication cables have a wide transmission frequency band, large communication capacity, and are less susceptible to external interference, but are not easy to maintain. Capable of transmitting telephone, telegram, data, and images, etc.

　　Selection of Mining Cables:

　　In the mine power supply system, high-voltage power supply lines generally use armored cables, which have a much lower failure rate compared to low-voltage power supply. The power supply in mining areas is a weak link in the power supply system, and the working environment is poor. Therefore, how to choose the type and cross-section of cables is related to the safety of power supply operation. The following introduces the selection of cables and the method of selecting cable cross-sections.

　　Development status of mining cables:

　　1. In recent years, there has been a lack of emphasis on adjusting the product structure in the wire and cable industry due to low-level repetitive construction. The contradictions in product structure are still prominent, and high-level products cannot meet the needs. For example, in terms of categories, China's bare wire production accounts for nearly 1/5, while developed countries only account for 1/10. In bare power lines, overhead lines and ordinary steel cored aluminum stranded wires account for the vast majority;

　　2. There are over 700 loss making enterprises in the industry with low economic benefits, accounting for more than a quarter of the total losses. The industry's sales revenue profit and tax rate was 11.7% in 1991 and decreased to 5% in 1995. Due to the continuous decline in profitability, an increase in loss making enterprises, and a general shortage of funds within the industry, the average asset liability ratio is as high as 70%;

　　3. The scale growth is too rapid, and the overall capacity of the wire and cable industry is more than twice the demand. The predicted demand for various product categories in 2000 is less than the production capacity.

　　Requirements for fixed laying of high-voltage cables for mining cables:

　　1. PVC insulated thick steel wire armored PVC sheathed power cables and cross-linked polyethylene insulated thick steel wire armored PVC sheathed power cables should be used in vertical shafts or tunnels with an inclination angle of 45 ° or more;

　　2. In horizontal tunnels or shafts with an inclination angle of less than 45 °, PVC insulated steel strips or fine steel wire armored PVC sheathed power cables, cross-linked ethylene steel strips or fine steel wire armored PVC sheathed power cables should be used;

　　3. Aluminum core cables can be used in the air intake inclined shaft, underground parking lot and its vicinity, and between the substation and the mining area substation; Copper core cables must be used in other locations;

　　4. Fixed low-voltage cables should use Mw armored or unarmored cables or mobile rubber sheathed flexible cables of corresponding voltage levels;

　　5. Non fixed high and low voltage cables must use rubber sheathed flexible cables that comply with the Mr818 standard. Mobile and handheld electrical equipment should use rubber sheathed cables;

　　6. Cables used for lighting, communication, signaling, and control should be armored communication cables, rubber sheathed cables, or M-type, factory type plastic cables;

　　7. Aluminum cores should not be used for low-voltage cables, and aluminum cores are strictly prohibited for low-voltage cables in mining areas.

　　Mining cable control core:

　　1. Increase the flexibility of coal mining machine cables used in coal mines;

　　2. Increase the relative slippage of the control wire core;

　　3. Increase the strength of cable conductors for coal mining machines used in coal mines;

　　4. Changing the conductor from the original bundle twisting structure to regular twisting can increase its bending performance, and then weaving steel wires outside the conductor to increase its strength;

　　5. The control wire core can be woven with a mixture of tinned copper wire and steel wire, which is also a good method.

　　Tianjin Cable Factory Branch adheres to the business philosophy of "customer first, service-oriented" and serves our customers with the business philosophy of "sincere cooperation, trustworthy management".

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• Copper core fire-resistant control cable