Electric cable

FIELD: electrical engineering; electric cables for signaling, control, and data transfer and processing systems.

SUBSTANCE: cable has at least one pair of insulated and stranded current-carrying conductors and cable sheath. Insulating material is either halogen-containing polymer (polyvinyl chloride), or halogen-free polyolefin base material (polyethylene), or its copolymer. Insulation thickness is chosen from equation strand pitch is found from equation h = 25(2Δ + d), where d is conductor diameter; εr is relative dielectric constant of insulating material. With diameter of cable current-carrying conductors being enlarged, capacitance of cable pair was reduced (other characteristics being retained at desired level.

EFFECT: enhanced capacitance of working load on cable pair.

1 cl, 4 dwg, 1 tbl

 

The invention relates to one of the branches of the electrical industry - cable engineering, and more particularly to electric cables for alarm systems, management, transmission and processing of data (communication). These cables are used in networks where for the organization of lines (loops) of different length cables with different diameters conductive wires. Such networks, in particular, refers fire network.

Known produced by domestic industry electric cables for alarm systems containing at least one pair of twisted among themselves lived, isolated electrically insulating polymeric halogen-containing material is polyvinyl chloride, and a shell.

Produced the following cables in accordance with THE 3581-02-472731-99 “Cables, paired cables for fire alarm systems”.

As follows from the above THAT the cables under these specifications, technical parameters and operational characteristics similar to the cables according to German standard DIN VDE 0815”.

From the specified German standard (commissioning with 01.09.85) known electrical cables containing at least one pair of twisted between the conductive wires, insulated electrically insulating polymeric material is PVC or halogen-free (halogen nesteriak) material and the shell.

The standard stipulates the use of conductive wires with a diameter of 0.6 mm and 0.8 mm, the insulating layer with a nominal thickness of 0.2 mm and 0.4 mm, respectively, the pitch insulated conductors installed standard 50 mm

Nominal value of the electrical capacitance of the pair insulated with polyvinyl chloride should not exceed 100 nF/km, and for a couple with insulation of halogen-free material is not more than 120 nF/km These cables are the closest (essential features) analogue for the invention.

Important electrical parameters of the cables, from the point of view of their use in these networks are the electrical resistance of the conductors and the working capacity of the pair. The electrical resistance of the conductors depends on its diameter (cross-section). When increasing the length of the working circuit is required to reduce the electrical resistance of the conductive wires, which is achieved by increasing the diameter (cross-section). However, increasing the diameter of the conductive wires will increase the electrical capacitance of the pair in the cable above the allowed value. In a known design of cable not provided for actions aimed at stabilizing the electric capacitance twisted pair lived during the transition from one diameter to another. And diabolisation of the listed capacity is limited, including, the specified standard. And this is explained as follows.

Consider the cables are used in the form of a loop, which connects the sensors (e.g. smoke detectors) and actuators (e.g., fire extinguishers). Each sensor and the device, which may be of the order of 100-130, contribute to the common electrical circuit capacity. It is believed that the effective load circuit is achieved when the self-capacitance of the cable does not exceed 100 to 120 nF/km

The invention is directed to solution of the problem - the creation of an electrical cable electrical characteristics at any diameter of the conductive wires, satisfying the consumer. During implementation of the invention was obtained technical result, regardless of the diameter of the conductive wires insulated with PVC or halogen-free material, capacity pair cable does not exceed the acceptable value (100-120 nF/km); however, other electrical characteristics remained at the level of operational reliability. All this, ultimately, leads to the possibility to increase the capacitive load on a couple of cable.

It is known that the electrical capacity of any section of insulation from the electrodes, including cable (in which veins are the capacitor plates, and insulating material, its dielectric) depends both theamericas sizes of its elements, and the electrically insulating material forming the dielectric.

In this case, the insulating material is selected as in the prototype, based on the operating conditions of the cable and must have certain electrical and physical characteristics. In this regard, to regulate the capacity of the pairs of the cable when changing the diameter of the conductive wires by selecting the insulating material is not possible.

As the insulating material is selected, as in the prototype, Galatasaray polymer - PVC or halogen-free material (in the prototype it is given at a functional level). Despite the fact that the chlorine content in PVC - 56,8% it is considered that from a physiological point of view it is completely harmless. The harmful effects of the products of decomposition: chlorine compounds, HCl, CO, etc. In the combustion of polyvinylchloride large amount of heat, forms a thick layer of smoke. Polyvinyl chloride and now finds wide application in both domestic and foreign cable technique and work on improving its performance, however, the question of its replacement halogen-free polymeric materials is extremely important. This is because these materials relative to the positive low smoke, they do not emit corrosive volatile products in the combustion conditions.

In a typical case, the halogen-free polymeric insulating material is a polymer base (usually a homopolymer or copolymer alienologo series elastomer or their composition), filled with fine-dispersed hydrate of aluminum or magnesium and contains some of the functional additive. High content of hydrates of metals (50-60%) reduces the amount of combustible gases generated by thermal decomposition of the material.

It is therefore not only PVC and halogen-free material, a polymer which is either polyethylene or its copolymer, or propylene, was used in the design of cables in accordance with the invention.

The properties of the cable, which are of particular interest when it is used, primarily, include dielectric strength, breakdown voltage and capacity of the pairs. Geometrical parameters of the cable elements in varying degrees, affect all of these characteristics. Therefore, to solve the problem of obtaining a technical result one decrease (or increase) the geometric parameter of one or another element of the cable is not possible. Therefore, when designing ka is the appropriate fields needed to identify the relationship between the geometric parameters of the cable elements (diameter conductive wires, insulation thickness, pitch lived in pairs), which would bring the capacity of the steam, do not exceed the permissible values, while retaining the other characteristics on the level of operational reliability.

The specified relationship was identified following set of essential features that ensure the achievement of the technical result and expressing the essence of the invention.

The electrical cable includes at least one pair of twisted between the conductive wires insulated with PVC or halogen-free material based on polymers, and membranes. When this polymer is, or polyethylene, or a copolymer, or propylene, thickness of insulation is determined from the condition,

and the pitch of isolated conductive wires is selected based on the ratio of h=25(2Δ+d)

where d is the diameter of the conductive wires,

εrthe relative permittivity of the insulating material, while εrfor PVC - 3,4÷3,6, εrfor halogen-free polymer materials on the basis of propylene or a copolymer of ethylene with propylene is in the range of 3.7÷3,9, same size εrprovides for halogen-free polymer-based material is an ethylene vinyl acetate. Of given the data seen what values εrfor all these materials differ slightly (within 3,4÷3,9).

Copolymers of ethylene have the same insulating properties as polyethylene, get them to modify the properties of the latter. Therefore, theoretically it is possible to conclude that any copolymer of ethylene, halogen-free, can be used as halogen-free insulating material.

In the essential features to characterize the sign of the insulated conductive wires used alternative concepts - PVC or halogen-free polymer material. This is explained in the following. The General concept that encompasses these insulating materials cannot be used, because it includes other materials that cannot be used in this case. And he and the other material can get (in conjunction with the identified relationship between the geometrical parameters of the cable) the same above technical result.

With regard to alternative concepts for the description halogen-free polymer base material, the situation is somewhat different. The General concept is the polyolefin, but in the design of the considered cable used were those that helped to get above those of the technical result.

The material for the sheath of the cable may be different. This polyvinyl chloride and other polymers, and halogen-free polymeric materials, and in some cases metals. All are determined by the operating conditions of the cable. However, the material for the shell does not affect the achievement of technical result.

The invention is illustrated in the drawing, in which figure 1 and 2 shows the transverse and longitudinal cross-section Troparevo cable.

The cable includes a conductive core 1, the insulation of the conductors 2 and the protective sheath 3. Under the protective sheath can be placed a screen in the form of laminated aluminum foil or braid of copper wires. In this drawing, the screen is not shown, since its presence or absence does not change the essence of the claimed invention. In figure 1 are given the designation insulation thickness Δ and the diameter of the conductors d. Figure 2 shows the pitch of the pair h.

As already mentioned, to solve the problem of obtaining a technical result is not possible in one decrease (or increase) the geometric parameter of one or another element of the cable, as each of these parameters in varying degrees, affects all of its major operational characteristics. For example, the capacity of the pairs of the cable can be reduced by increasing the thickness of insulation &x00394; but it will also result in the reduction of the electrical insulation strength - the strength of the electric field, which in any point of the insulation breakdown occurs. At the same time, the breakdown voltage isolation increases with its thickness.

Considering the invention relates to a cable, wherein the pair formed a twisted between an insulated electric conductors. The less the pitch - h, the higher the immunity of the cable (which is especially important for cable connection), but most of its capacity.

From all this it follows that to solve the problem only by finding the relationship between the geometric parameters of all those elements of a cable that affect its performance.

This confirms all the data obtained during the construction of the cable and are outlined below.

Examples Troparevo cable is made from PVC and halogen-free material are shown in table 1. From this table it can be seen that with the increase in the diameter of the conductors. The insulation thickness and the pitch grow, and it can be assumed that the capacitance of the pair should be reduced, but it increases the diameter increases, but remains within acceptable limits. This is explained as follows: when designing cable, regulatory documents the AMI fixed values of the diameters lived, and the increase in diameter causes a significant increase in capacitance of the cable.

The proposed correlation can reduce this growth, while maintaining its value within the required standards. Figure 3 shows the dependence of the linear capacitance of the cable from changes in diameter lived: 1 - cable with insulation of halogen-free material based on polypropylene (εr=3,9); 2 - cable with insulation of halogen-free material based on polyethylene (εr=3,7); 3 - for cables insulated with PVC.

The relationship of two parameters - the insulation thickness Δ and the step of twisting insulated conductors h is illustrated graphically in figure 4, which presents the change in heat input capacity Troparevo cable conductors with a diameter of 0.8 mm, Curve 1 represents the graph of the linear capacitance of the cable from the insulation thickness at a constant pitch pairs 35 mm Curve 2 represents the graph of the linear capacitance of the cable from the pitch of the pair at a constant insulation thickness of 0.45 mm, These two curves have an intersection point, which indicates the existence of minimum values of the linear capacitance of the cable when the ratio of the minimum insulation thickness of 0.45 mm and a minimum pitch of a pair of 35 mm Such dependencies can be constructed for other values of the diameters of the veins, which clearly illustrates the relationship here is announced the winner of the parameters.

Table 1
The diameter comprobadas. veins d, mmInsulation thickness Δin accordance with the invention, mmThe pitch of the pair h, in accordance with the invention, mmLinear capacitance of the pair in accordance with the invention,the nF/km
 PVCBMPVCBMPVCBM
0,60,39-0,400,41-0,42353674-7678-82
0,80,45-0,460,47-0,48434480-8485-88
0,970,49-0,500,51-0,52495085-8891-94
1,13about 0.53-0.54up 0,56 0,57555788-9193-97
1,380,59-0,61of 0.62 to 0.63646694-98100-104
1,760,66-0,680,70-0,717780103-106108-113
PVC - polyvinyle the ID.

BM - halogen-free material.

Electrical cable containing at least one pair of twisted between the conductive wires insulated with PVC or halogen-free material based on polymers, wherein the polymer base is either polyethylene or its copolymer, or propylene, thickness of insulation is determined from the condition

the pitch of isolated conductive wires is selected based on the ratio of h=25(2Δ+d), where d is the diameter of the conductive wires; εrthe relative permittivity of the insulating material.



 

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FIELD: electrical engineering; electric cables for signaling, control, and data transfer and processing systems.

SUBSTANCE: cable has at least one pair of insulated and stranded current-carrying conductors and cable sheath. Insulating material is either halogen-containing polymer (polyvinyl chloride), or halogen-free polyolefin base material (polyethylene), or its copolymer. Insulation thickness is chosen from equation strand pitch is found from equation h = 25(2Δ + d), where d is conductor diameter; εr is relative dielectric constant of insulating material. With diameter of cable current-carrying conductors being enlarged, capacitance of cable pair was reduced (other characteristics being retained at desired level.

EFFECT: enhanced capacitance of working load on cable pair.

1 cl, 4 dwg, 1 tbl

FIELD: cable or rope manufacturing industry, possible use for producing flexible current-conductive wires of ropes.

SUBSTANCE: proposed method for laying multi-wire current-conductive wire is performed in accordance to system m x (n x d), where m -number of strands in lay of cable or rope; n - number of wires in each strand; d - diameter of elementary wire. For realization of aforementioned laying system in m giving devices of spinning machines of hoop or cigar type coils are mounted with clusters of n wires on each coil, while output of wire from giving devices to frames or rotor of machines is performed in direction, opposite to movement of cable template. Cluster with n wires during movement from giving coil onto rotating frame is laid with step h=v/w, where v - linear speed of pulling device, m/min, w - turns of frame, 1/min. during displacement from the frame into caliber, strand is also laid for step h in the same direction. Therefore, at output direction of lay is produced which matches direction of lay of strand and step of lay of wires in strand is averagely twice less than step of lay of strands in the lay.

EFFECT: possible laying of multi-wire cable products, providing for simultaneous laying of strands and laying of cable or rope using said strands.

5 cl

FIELD: electrical engineering including cable engineering; midget control cables for wire communication lines of small-size missiles and their manufacturing process.

SUBSTANCE: proposed midget control cable has two electrically insulated enameled copper conductors (current-carrying conductors), one strengthening complex thread of cross lea securing winding of three polyamide threads forming thread assembly, as well as four strengthening complex threads placed on top of cross securing winding in parallel with copper conductors, two-layer lea winding of two polyamide threads wound in opposite directions, and one complex thread. Proposed method for manufacturing midget control cable includes manufacture of thread assembly followed by finishing midget control cable for which purpose four strengthening complex threads are arranged in parallel with thread assembly and two-layer winding is placed overall.

EFFECT: improved electrical and mechanical characteristics, ability of using cable immersed in water including sea water.

2 cl, 3 dwg

FIELD: electrical engineering including cable engineering; midget control cables for wire communication lines of small-size missiles and their manufacturing process.

SUBSTANCE: proposed midget control cable has two electrically insulated enameled copper conductors (current-carrying conductors), one strengthening complex thread of cross securing lea winding of three polyamide threads forming thread assembly, as well as seven strengthening complex threads placed on top of cross securing winding in parallel with copper conductors, and secondary securing winding of one complex strengthening thread; thread assembly is impregnated with water-repelling liquid. Proposed method for manufacturing midget control cable includes manufacture of thread assembly followed by finishing midget control cable for which purpose seven strengthening complex threads are arranged in parallel with thread assembly whereupon finished midget control wire is wound on take-in reel.

EFFECT: improved electrical and mechanical characteristics, ability of using cable immersed in water including sea water.

2 cl, 2 dwg

FIELD: electricity.

SUBSTANCE: in the known method including cable wires ends fixing to receiving device, their subsequent drawing with concurrent wires twisting around core, the new consists in cable wires ends fixing to receiving device using terminal in which wires are pressed together with cable core, and wires twisting around core is executed by disk rotation at angular velocity that is found from empiric formula. To implement declared method for twisting wires of water-cooled cable device is offered which in contrast to known device for manufacturing additionally contains table and press for squeezing cable terminals. It is reasonable to insert short tubes in peripheral holes of disks. Suggested device allows to fabricate cables of definite length with embedding wires into terminals, at that effective wire twisting is performed taking in consideration various cable psrsmeters. Tubes installed in disks prevent wire damage during drawing.

EFFECT: widening of technical facilities arsenal, method and device for manufacturing cables of definite length with regard to required parameters and quality improvement.

3 cl, 2 dwg, 1 tbl

FIELD: electric engineering.

SUBSTANCE: composite core is arranged in the form of one or multiple-strand structure, which represents a lengthy rod or twisted lengthy rods of high-strength hear resistant of continuously reinforced composite material. Composite material consists of high-strength reinforcing fiber of one composition with filling extent of 30-85 wt % and thermosetting heat resistant polymer binder with content of 15-70 wt %. Core for protection against damages at the stage of winding of current-conducting layer and under conditions of operation against effect of active factors of environment comprises external metal or heat resistant varnish-cloth shell. In process of core manufacturing, shaping of core profile is carried out by means of cord pulling through heated draw plate or by means of core profile shaping directly in protective external metal shell.

EFFECT: core makes it possible to improve throughput capacity, to provide for minimum sagging of overhead wire of power transmission line and to reduce loads at power transmission line supports.

18 cl, 5 dwg, 2 ex

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