Mining cable

Produced by Anhui Tiankang GroupMining cableIt is the abbreviation for coal mine cables. Mining cables are all flame-retardant cables and should be issued a mining product safety mark certificate by the National Mining Product Safety Mark Center. U-shaped (M-type) rubber sheathed cable for coal mines

This product is produced in accordance with GB/T12972-2008 "Rubber sheathed flexible cables for mining" and MT818-2009 "Flame retardant cables for coal mines". It can also be produced according to the recommended standards of the International Electrotechnical Commission IEC, British standards, German standards, and American standards according to user needs.

Scope of Application

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Mining rubber sheathed flexible cables are suitable for mobile laying cables used in mining power equipment with rated voltage U0/U 8.7/10KV and below.

Usage characteristics

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The rated voltage U0/U of the power frequency is 380/660V, 660/1140V, 1.9/3.3kv, 3.6/6kv, 6/10KV, 8.7/10KV, and 300/500V.

The maximum allowable working temperature for cable conductors is 65 ℃ and 90 ℃

The cable allows a low working environment temperature of -35 ℃

● Cable bending radius: not greater than 6 times the outer diameter of the cable.

Mining cables include MC cables, MCP cables, MZ cables, MZP cables, MYQ cables, MY cables, MCPTJ cables, MYPTJ cables, MVV cables, MKVV cables, MYJV cables, MKYJV cables, MHYV cables, UGF cables, high-voltage mining cables, 10kV rubber sheathed cables, 6kV mining cables, mining mobile cables, mining flame-retardant cables, MCPT cables, and mining rubber sheathed cables.

choice

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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.

　　Mining cableSelection of cable model

The selection of cable models is closely related to the reliability, safety, and economic feasibility of power supply. Article 467 of the Coal Mine Safety Regulations stipulates the following selection requirements for cables:

The level difference of the actual cable laying location should be compatible with the allowable cable laying level difference specified.

2. The cable should have a conductor of sufficient cross-section for protective grounding.

3. It is strictly prohibited to use aluminum wrapped cables.

4. Flame retardant cables that have passed inspection and obtained the safety mark for coal mining products must be selected.

5. The cross-section of the main cable core should meet the requirements of the power supply line load.

6. Requirements for fixed installation of high-voltage 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 central 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 dedicated rubber sheathed cables.

(6) Cables used for lighting, communication, signaling, and control should be armored communication cables, rubber sheathed cables, or M, factory, 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.

Selection of cable cross-section

The selection of cable cross-section includes the selection of high-voltage cable cross-section and low-voltage cable cross-section, with the selection of low-voltage cable cross-section being the main focus.

1. Selection of the main core wire of the cable

The low-voltage power supply lines in general mining areas are relatively long, and the current flowing through the cables during operation will cause voltage drop and heat generation. To ensure the normal operation of cables and motors, the following four principles should be followed when selecting cable cross-sections:

(1) When the cable is running normally, its actual temperature rise should not exceed the maximum temperature rise allowed by the insulation.

(2) Select based on the allowable voltage loss during cable operation.

(3) The selection of cable cross-section should meet the requirements of mechanical strength.

Mining cables refer to wire and cable products used for surface and underground equipment in coal mining industry. This includes cables for coal mining machines, transport machines, communication, lighting, and signal equipment, as well as drill cables, cap light wires, and power cables for underground mobile substations.

Search for safety signs

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The National Mining Product Safety Mark Center (Mining Product Safety Mark Office) is authorized by the State Administration of Work Safety to undertake the management of mining product safety marks, including accepting safety mark applications, organizing and implementing technical reviews, on-site evaluations, product sampling inspections, issuing safety marks, and supervising and managing enterprise certification. The National Mining Product Safety Mark Center adheres to the work policy of "fairness, openness, scientific efficiency, rigorous confidentiality, integrity and enthusiasm", strictly implements national laws and regulations and relevant provisions on safety production, operates in a procedural manner, and manages in a standardized manner. There are currently offices (Policy Research Office), Comprehensive Department (International Department, Information Department), Technical Department, Review Department, Inspection Department, Supervision Department, Finance Department and other departments.

development status

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After several years of rapid development, China's mining cables have formed a considerable scale, but due to production capacity exceeding demand, there is a situation of oversupply. The production capacity has greatly exceeded this year's predicted demand value, while wire and cable enterprises are facing the urgent need to improve the technological content of their products.

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, the number of loss making enterprises has increased, and funds in the industry are generally tight, with an average asset liability ratio of up to 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.

price calculation

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The price formula for mining cable series is as follows: weight of copper X copper price calculation: wire diameter ÷ 2=1.25X1.25X3.14=square number X number of wires X0.89X current copper price+10% processing fee. The cost price calculation of mining cables is square X1.83=weight of copper X current copper price+armor price (weight X0.4 yuan/jin)=cost price+10% processing fee. Cable price=manufacturing material cost+fixed cost+tax+business fee+profit. Manufacturing material cost=material cost * (1+material consumption) (material cost is the theoretically calculated value). Fixed costs vary depending on the situation of each company, generally including production wages, management wages, utilities, repair costs, depreciation costs, rent costs, and transportation costs

increase lifespan

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During use, the local bending radius of the coal mining machine cable is much smaller than the standard bending radius of the cable. The cable is frequently subjected to the combined effects of excessive bending, stretching, and other two or more stresses for a long time. In addition, the cross-sectional area of the control core conductor is much smaller than that of the main core conductor, resulting in the breakage of the 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.