Cable termination carried out before installation of couplings and seals. It consists of sequential stepwise removal over a certain length of protective covers, armor, sheath, screen and cable insulation. The dimensions of the cutting are determined according to the technical documentation, depending on the design of the cable and the coupling (terminal) mounted on it, the voltage of the cable and the cross-section of its cores.
When starting to cut the end of the cable, check that there is no moisture in the paper insulation and conductors. If necessary, remove existing wet insulation, excess length of ends, areas under sealing caps and cable end grips, as well as those passing through the cheeks of the drums. Defective areas of the cable are cut off with NS sector scissors (Fig. 18, a).
Cable cutting begins with determining the installation locations of the bands, which are calculated using the formula: A = B + O + P + I + G. At the end of the cable, measure the distance A (Fig. 19, a) and straighten this section. Next, wind up the resin tape (see Fig. 18, b) and apply a bandage (see Fig. 18, c) from two or three options of galvanized steel wire manually or using a special device (cutter). The ends of the wire are grabbed with pliers, twisted and bent along the cable.
A - cutting the end of the cable with NS scissors; 6 - winding made of resin tape; V- application of a wire bandage; G- cutting armor; d, f - Removing Armor, Yarn, Cushion and Cable Paper
Rice. 18. Technology for cutting cable ends, applying bandages and removing covers
The outer cable cover is unwound to the installed bandage and is not cut off, but is left to protect the armor stage from corrosion after installation of the coupling.
A second bandage is applied to the cable armor at a distance B (50-70 mm) from the first wire bandage. When installing cast iron connecting and branch couplings and end seals in steel funnels, the armor section is used to seal their necks, so size B is increased to 100-160 mm. Along the outer edge of the second bandage, an armor cutter or a hacksaw is used to cut the upper and lower armor strips (no more than half their thickness), then the armor is unwound (see Fig. 18, d, e), broken off and removed.
Next, remove the pillow (see Fig. 18, f). To do this, the cable paper and bitumen composition are heated with a propane torch or blowtorch. The cable sheath is cleaned with a cloth soaked in transformer oil heated to 35-40 o C.
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To remove the shell, circular cuts are made at a distance of 50-70 mm from the armor cut. In cast iron couplings and steel end funnels, the shell section is used only for connecting the grounding conductor, therefore the specified distance is reduced to 20-25 mm (see Fig. 19, a).
A - with belt paper insulation; b- with plastic insulation; 1 - outer cover; 2 - armor; 3 - shell; 4 - waist insulation; 5 - core insulation; 6 - cable cores; 7 - bandage; A, B, I, O, P, G and W - cutting dimensions
Rice. 19. Cutting the ends of a three-core cable.
When marking lead sheaths (Fig. 20, a), stake cuts to half the depth are made using a fitter's tool (Fig. 20, b) or special knife with a cutting depth limiter (Fig. 20, c). From the second annular cut at a distance of 10 mm from one another (Fig. 20, e, f), the strip of shell between the two cuts is grabbed with pliers and removed (Fig. 20, i). The remaining part of the shell is moved apart (Fig. 20, j) and broken off at the second annular cut. Between the first and second annular cuts the shell remains temporarily. It protects the insulation from damage when the cores are bent.
For cables with an aluminum sheath, cuts are made with a steel knife NKA-1M with a cutting disk (Fig. 20, d). From the second annular cut a screw cut is made (Fig. 20, g). The corrugated aluminum shell is removed after cutting it at a distance of 10-15 mm at the protrusion of the corrugations. Next, the cable cores are freed from the belt insulation and gradually bent according to the template. Then prepare a place for connecting the grounding (Fig. 20, a, b).
To connect cable cores to the contact terminals of electrical devices, they are terminated with lugs secured to the cores by crimping, welding or soldering. Termination of single-wire conductors can also be performed by forming a ferrule from the end of the conductor. The connection of cable cores in couplings is carried out in connecting and branch sleeves by crimping, welding or soldering.
The technology for connecting aluminum cores by crimping is shown in Fig. 22, a-z.
The ends of aluminum sector conductors are rounded before crimping: multi-wire - with universal pliers, single-wire and combined - with a special tool ISK or KS, as well as a tool included in the NISO set.
When crimping, the tip or sleeve is put on the core (the core must enter the tubular part of the tip until it stops, and in the sleeve the ends of the cores must rest against each other in the middle of it), installed in the mechanism for pressing, first retracting the punch.
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A- marking; b, c - circular cuts of lead sheaths; G - circular cuts of aluminum shells; d, v ~ longitudinal cuts of lead sheaths; and - cutting the aluminum shell along a helical line; h, m - cuts of plastic shells; and, to- removal of lead sheaths;
l - removal of aluminum shells; n - removal of corrugated aluminum shell
Rice. 20. Operations for removing cable sheaths:
The operations of connecting and branching by direct fusion of the processed ends of the cores with solder are shown in Fig. 23, a. Into the molds (sleeves) 2 cores 1 are inserted so that their joint is in the middle of the mold (for cores with ends cut at an angle of 55°, the gap between the ends is left about 2 mm). Detachable molds are fastened with bandages or locks, and the gaps between the core and the mold are sealed with asbestos cord 7. For more complete filling with solder, the molds are placed in a horizontal position, protective screens are put on the cores 5. When connecting cores with a cross-section of 120-240 mm 2, coolers are additionally installed.
A - wire bandages; b- soldering; 1, 3 - bandage at the ends
shell and outer cover; 2, 4 - bandage for soldering the grounding conductor
Fig. 21. Methods of attaching the grounding conductor to a metal sheath
The mold (sleeve) is heated with the flame of burner 3. At the same time, a stick of solder 4 is introduced into the flame, the melt of which is stirred with stirrer 8 until the mold is completely filled and slag is removed. After this, heating is stopped. Lightly tap the mold to compact the solder. During soldering, crucible 11 (Fig. 23, b) is poured with pre-molten solder from ladle 9 and placed at a certain distance to prevent additional heating of the core insulation. A tray 10 is placed between the crucible and the soldering point, along which the excess will flow (the tray should not touch the core insulation).
The technology for insulating connection points and terminating cable cores with paper rolls and rolls is shown in Fig. 24, a-e. After connecting the cores, the paper insulation is washed with an impregnating composition heated to 120-130°C. Then the upper color strips are removed from the core insulation: the insulation is cut in steps over a section 16 mm long for 6 kV cables and 24 mm for 10 kV cables. The width of each step is 8 mm; eight strips of paper insulation are cut off at each step.
Restoration of the insulation of the exposed sections of the cores is carried out with rollers 5 mm wide (winding is done to the outer surface of the connecting sleeve or factory insulation, depending on what has a smaller diameter). Further insulation is carried out with rollers 10 mm wide. During the winding process, the insulated cores are periodically scalded with MP impregnating composition heated to 120-130°C. Further insulation is carried out in cylindrical rolls up to 300 mm wide, depending on the brand of coupling.
A - cleaning the inner surface of the liner; 6~ lubrication of the inner surface of the liner; V - the ends of the cores with the insulation removed; G - stripping the ends of the cores; d - lubricating the cores with quartz-vaseline paste; e- putting the sleeve on the cores; and- crimping the core; z -~ measurement of residual thickness at the pressing site
Rice. 22. Technology for connecting aluminum cores by crimping.
A few decades ago they were used for regular telephony. The design of these cables has remained virtually unchanged, but the equipment that is “hung” on these cables has noticeably improved. Today, the speed of information transfer via xDSL technologies reaches hundreds of Mbit/s. Due to availability huge amount of various cables, it is impossible to do without markings in the name of the cables indicating the main parameters.
Consider, for example, 20x2x0.4 for the purpose of decryption example:
telephone (T) cable with polyethylene core insulation (P), with polyethylene sheath insulation (P), with a film screen (ep), with a hydrophobic filler (Z) and an armor covering (B).
Numerical designations are deciphered as follows:
20x2 - the cable has 20 pairs in its core;
0.4 - core diameter in mm.
In TSV cables, the second and third letters are deciphered as follows:
Letter C - station, B - vinyl shell.
For small-pair cables, the letter M is added to the marking - MTPPZ, MTPPepZ.
Cables KAPZ, KAPZop practically do not differ from MTPPZ and their decoding is as follows: subscriber cable (K) with polyethylene insulation (P) and hydrophobic filler (Z).
About systems for twisting cores in cables such as TPP
Today, twisted cables are no longer produced, but are still used.
Rice. 1 - arrangement of pairs in a coiled cable.
Rice. 2 - Layered cable design
Such a cable has a poor color of cores - 1 pair is red, 2 pairs are blue, the remaining pairs are the same color. Counting pairs in such a cable is difficult, which contributed to lower quality work and common mistakes at adhesions. Positive side This cable, perhaps, has a smaller cable thickness when compared with bundle twisting.
Bundle twist
Rice. 3 - bundle twist
The figure shows: under the number 1 - a pair of cores; 2 - four cores; 3 - elementary beam; insulation; 5 - screen; 6 - polyethylene shell; 7 - screen wire.
A cable with such twisting is a product in which pairs are twisted in bundles of 5 or 10 pieces. The bundles are formed by two threads that wrap around the bundle and also contain a special colored thread to distinguish the bundles from each other.
Rice. 4 - Color chart of pairs in the top ten cables TPV, TPP, TSV, TPPep, TPPepZ
Rice. 5 - Coloring of TPP cable pairs
Charging BKT box plinths with TPPepZ cable
The procedure for counting pairs and fours by color is prescribed in the relevant standards.
The cable cores, collected in bundles, are wrapped with PVC tape to protect the insulation from the negative influences of temperature. The next layer is the screen and tinned core. And then the shell. Initially, a TPV cable with a vinyl sheath was manufactured. When using the cable in the ground, it was noticed that it loses its properties due to the action of moisture. Later, a TPP cable with a polyethylene sheath was developed, which turned out to be less susceptible to moisture, but more fire hazardous. Therefore, depending on the conditions in which the cable is used, a modification with an appropriate sheath is selected.
You can receive the ordered goods from the Vionet company in the following cities:
In Anapa, Arkhangelsk, in Abakan, in Adler, in Aktau, in Almetyevsk, in Aktyubinsk, in Almaty, in Asnan, in Anadyr, in Angarsk, in Astrakhan, in Apatity, in Atyrau, in Arzamas;
In Blagoveshchensk, in Balakovo, in Biysk, in Belgorod, in Balkhash, in Borovichi, in Bryansk, in Bratsk, in Belogorsk, in Borisoglebsk, in Berezniki, in Barnaul, in Bugulma, in Budennovsk;
In Vologda, in Volgograd, in Vladimir, in Veliky Novgorod, in Volgodonsk, in Velikiye Luki, in Voronezh, in Vladivostok, in Volzhsk, in Volzhsky;
In Zheleznodorozhny; in Yekaterinburg, in Dzerzhinsk, in Dimitrovgrad, in Zabaikalsk, in Zelenodolsk, in Izhevsk, in Ivanovo, in Yoshkar-Ola, in Irkutsk;
In Kurgan, in Kazan, in Kaluga, in Krasnodar, in Kostroma, in Kemerovo, in Kamensk-Uralsky, in Karaganda, in Kirov, in Kokchetav, in Kolomna, in Kotlas, in Krasnoyarsk, in Kuznetsk, in Kursk, in Kustanai, in Kyzyl-Orda, in Kaliningrad, in Kamyshin, in Komsomolsk-on-Amur;
In Moscow, Magadan, Murmansk, Miass, Magnitogorsk, Lipetsk;
In Nizhny Tagil; in Nizhny Novgorod, in Nizhnekamsk, in Novy Urengoy, in Naberezhnye Chelny, in Noginsk, in Nalchik, in Neftekamsk, in Nevinnomyssk, in Novorossiysk, in Novocheboksarsk, in Novomoskovsk, in Novokuznetsk, in Noyabrsk, in Novosibirsk, in Nizhnevartovsk;
In Orsk, in Orel, in Obninsk, in Orenburg, in Omsk, in Oktyabrsky;
In Perm, in Podolsk, in Petrozavodsk, in Pskov, in Penza, in Petropavlovsk-Kamchatsky, in Petropavlovsk, in Pushkino, in Pavlodar, in Pyatigorsk;
In Ryazan, in Rybinsk, in Rostov-on-Don, in Rossosh;
In St. Petersburg, in Syktyvkar, in Sevastopol, in Severodvinsk, in Salavat, in Stary Oskol, in Saransk, in Saratov, in Samara, in Serpukhov, in Smolensk, in Semipalatinsk, in Sochi, in Solnechnogorsk, in Stavropol, in Sterlitamak , in Syzran, in Surgut;
In Tver, in Tula, in Tuapse, in Tyumen, in Tambov, in Taganrog, in Tolyatti, in Taraz, in Taldy-Kurgan, in Tomsk;
In Ulyanovsk, in Ufa, in Ussuriysk, in Ulan-Ude, in Ukhta, in Uralsk, in Ust-Kamenogorsk, in Khabarovsk, in Khanty-Mansiysk, in Chita, in Cherepovets, in Chelyabinsk, in Cheboksary, in Chimkent, in Engels , in Ekibastuz, in Yaroslavl, in Yakutsk, in Shakhty, in Yuzhno-Sakhalinsk.
Wires and cables are cut in the following order:
using reference books, determine the dimensions of the groove depending on the design of the conductor and the type of connecting or terminal device;
mark the cutting using cable strips or templates;
stepwise apply several turns of fixing bands made of galvanized steel or copper wire, twisted twine, cord or nylon thread, coarse threads, as well as cotton or plastic tape;
make circular transverse and linear longitudinal cuts of shells to be removed (armored, lead, aluminum, plastic shells and monolithic insulation);
remove or roll up the covers to be removed;
separate the ends of the strands of multicore conductors, i.e. give them a shape and location convenient for the next operation;
they process the bare end sections of the conductive conductors, i.e., they clean them to a metallic shine, tin them, coat them with fluxes, quartz vaseline paste or conductive glue, and fuse the stranded conductors into a monolith.
Note that the need for the above operations is determined by the design of the conductors. They are carried out in full for power cables with paper insulation, and for the simplest conductors, the cutting technology comes down to removing the polyvinyl chloride insulation and processing the core.
Wire cutting involves the sequential removal of the protective, sealing, insulating and other sheaths of current-carrying conductors for the purpose of connecting or terminating them. The dimensions of the grooves depend on the diameter of the core, the method of its connection to another core or termination, the type of contact clamp of the device or plug connector and the diameter of the contact bolt. In each specific case of cutting, these dimensions are determined from reference books or by calculation.
The price depends on the diameter of the step and is usually 3... 12 mm. Depending on the required strength, the bandages are made of galvanized steel or copper wire with a diameter of up to 1 mm, twisted twine with a diameter of 1 mm or raw thread. For strengthening, non-wire bandages are coated with perchlorovinyl composition No. 1 or BF glue.
The length of the cutting is determined by design considerations and location and is taken according to the core that, according to the wiring conditions, turns out to be the longest.
For example, a 5 mm long bandage of twine is applied to a cotton braided wire. At a distance of 1...2 mm from the bandage, the cotton braid is cut and removed. The second bandage is applied to a winding of rubberized fabric. The length of the second bandage, made with the same twine, is approximately half as long as the first. The rubberized winding is removed by unwinding it from the end of the wire and cutting it off near the second bandage.
Depending on the number of wire strands and the conditions of its cutting (for example, on the width of the routing of the ends of the wires for connections), the length of the rubber insulation remaining on the wires is determined (5... 10 mm with a small number of strands and simple routing, 50... 100 mm and more - with a large number of veins).
Rubber insulation is removed from the ends of the cores (for example, using KSI-2M pliers).
Depending on the adopted connection method (pressure testing, welding, etc.), the required length of the bare sections is determined and the excess ends of the cores are cut off.
Paper-insulated cables are cut in the following order. Having determined the cutting dimensions (Fig. 7.6) using a cable ruler or according to special tables and making a bandage with galvanized steel binding wire with a diameter of 1... 1.5 mm (2 - 3 turns), unwind the outer jute cover from the end of the cable to the bandage (Fig. 7.7, a). The covering material is not removed, but is wound onto an uncut section of the cable for subsequent use when installing couplings.
At a distance B (see Fig. 7.6) from the first bandage (or B from the end of the cable when indoor installation) a bandage made of steel wire is applied to the armor, while clasping the armor with both hands in mittens, slightly loosen the tension of the belts of its cushion
with an effort directed towards their winding. The armor is cut along the edge of the second bandage with an armor cutter, unwound manually (in mittens) and removed (Fig. 7.7, b, c).
The armor pad tape is also unwound and cut along the edge of the bandage. For reinforced cushions consisting of a layer of bituminous composition, plastic tapes, a polyvinyl chloride or polyethylene hose, crepe paper and another layer of bitumen composition on a hermetic shell, these layers are successively removed: wash off the outer bitumen layer; unwind and remove plastic tapes; cut longitudinally and remove the hose, cutting it along the edge of the bandage; lightly heat the burners with quick fire and remove the crepe paper; warm up and remove the bitumen layer from the shell with rags soaked in gasoline.
At distances (from the bandage on the armor) B and O + P + B (see Fig. 7.6), two annular cuts of the shell are made sequentially to half its thickness (Fig. 7.7, d) with a special cable knife. Then, two longitudinal parallel cuts are made on the lead sheath from the outer ring cut to the end of the cable at a distance of 10 mm. The strip formed by these cuts is carefully pulled out, starting from the annular cut of the shell, using pliers, unbent and removed manually (Fig. 7.7, e, f). The shell band is left between the two annular cuts. Its width at voltages up to 1 kV should be 20 mm, and at voltages 6... 10 kV - 25 mm.
0 ~ unwinding of the protective cover; b - cutting the armor; c - removal of armor; g - incision of the shell; d - strip removal; e - removal of the shell; g - screw cut of the aluminum shell
To remove the smooth aluminum sheath, the cutting roller of the knife is rotated 45° relative to its position when making annular cuts, the knife is secured on the cable and a screw cut is made from the second annular cut to the end of the cable (Fig. 7.7, g). Squeezing the sheath from the end of the cable, tear it along the line of the screw cut using pliers.
At a distance G from the end of the cores (see Fig. 7.6) or I from the cut of the waist insulation, apply a bandage of cable yarn or dry coarse thread (2 - 3 turns), remove temporary bands from the ends of the cores, unwind and break along the string at the edges of the bandages cable paper.
/-vm removal of the smooth aluminum sheath, the cutting roller of the knife is rotated 45° relative to its position when making annular cuts, the knife is secured on the cable and a screw cut is made from the second annular cut to the end of the cable (Fig. 7.7, g). Squeezing the sheath from the end of the cable, tear it along the line of the screw cut using pliers.
At a distance W, black semiconducting paper is unwound and torn along the edge of the bandage 8 of the belt insulation, and then the cable paper of the belt insulation.
Cable paper is the main insulation of high voltage cables. After winding the cable, it is impregnated with electrical insulating oil. When wound onto a cable core, paper strips are subjected to mechanical tension, and during cable laying they are subject to bending, so the cable paper must have sufficiently high mechanical strength during stretching and bending.
Cable papers are produced from sulphate cellulose, predominantly fat-ground, in order to ensure high mechanical properties, high density and low porosity. Impregnating liquid substances (oil or oil-rosin composition) are broken by paper during impregnation into thin films and channels, significantly increasing its electrical strength. The electrical strength of unimpregnated cable paper is 6...9 MV/m, and that of impregnated cable paper is 70...80 MV/m.
Cable papers produced for insulating cores of power cables for voltages of 35, 110 and 220 kV differ from each other in the number of layers, thickness, bulk density, air permeability and other characteristics.
The wiring and bending of the cores is carried out as follows. Before the operation, after checking whether the coupling or funnel blank is put on the cable (straightened and cleaned couplings or funnels should be put on one of the cables to be connected at the very beginning of cutting and placed in an area previously wrapped with a clean rag), thread bandages are applied to the ends of the core insulation .
A template is used to bend the cores. The radius of any bend must be at least ten diameters of the connected cores. To avoid contamination and moistening of the insulation, bending and routing of conductors should be performed using plastic or medical gloves. When wiring, all the cores at the root of the cut are tightly squeezed with one hand so as not to damage the insulation with the edge of the sheath.
At a distance G from the end of the cores (see Fig. 7.6) or I from the cut of the waist insulation, apply a bandage of cable yarn or dry coarse thread (2-3 turns), remove temporary bands from the ends of the cores, unwind and break along the string at the edges of the bandages cable paper.
Then the grounding conductor is installed. It must be copper, stranded. For cables with core cross-sections of 10, 16...24, 50...120, 150...240 mm 2, the recommended cross-sections of grounding conductors are 6, 10, 16 and 25 mm 2, respectively.
The length of the grounding wire is determined by the dimensions of the couplings and the type of supporting structures of the end couplings and terminations.
When using lead couplings, the grounding wire is attached to the conductive sheaths of the cable only with bands. The cable armor is cleaned and tinned (both armor tapes). The grounding wire is secured to the armor with a steel wire bandage and soldered to both armor strips and the bandage. If the cable has wire armor, then the bandage and armor are soldered in a circle. The free end of the grounding wire is placed along the uncut section of the cable.
Questions for self-control
I. 1. What is a cable?
2. What is a wire?
3. Cables with what insulation do you know?
II. 1. What determines the dimensions of wire cutting?
2. What is the basic requirement when cutting wires?
3. What tools are used when cutting?
III. 1. Explain the procedure for cutting the wire.
2. Explain the procedure for cutting the cable.
3. How is the grounding conductor installed?
7.3. Connection and termination of wires and cables
The connection and termination of copper and aluminum conductors of insulated wires is carried out in several ways: crimping, welding (thermite, electric, contact heating, gas), soldering, mechanical compression. Crimping is the most widely used as it is the cheapest and most reliable.
Connection and termination by soldering are currently rarely used, since soldering, although it ensures a reliable connection, is labor-intensive and requires significant consumption of non-ferrous metals. Welding aluminum conductors by contact heating is simple and produces reliable contact, but requires electricity. Thermite welding is promising, as it does not require the use of bulky equipment and is technologically simple. The choice of connection method, branching and termination depends on the material of the cores, their cross-section, design voltage and is determined by the availability of equipment and materials.
Crimping is used for connecting and terminating both copper and aluminum conductors of wires. However, crimping aluminum cores has some peculiarities, since the presence of an oxide film on them, as well as on the inner surface of the sleeves and the cylindrical part of the tips, requires thorough cleaning of the elements being connected and special means of protection against further oxidation both during the process of creating contact and during operation .
Protective agent The contact surfaces are quartz Vaseline paste, consisting of technical Vaseline and specially ground quartz sand. During crimping, solid quartz particles destroy the oxide film, helping to create reliable point contacts, and Vaseline prevents their oxidation.
When preparing for crimping, the aluminum core, cleared of insulation residues, is coated with quartz-vaseline paste, cleaned with a metal brush, the dirty lubricant is removed with a rag and a clean one is applied. The tubular part of the tips and sleeves used is also filled with paste.
The copper tips of the sleeve, as well as the cores of wires and cables, need only be cleaned to a metallic shine.
There are three methods of crimping: local indentation, continuous (multifaceted) crimping and combined crimping. During local indentation, the holes formed must be coaxial to the core being pressed and to each other.
When connecting and terminating wire cores by crimping, it is necessary to ensure:
keeping contact surfaces clean; required contact pressure; bringing the compression to the required dimensions; the depth of crimping specified according to the instructions; correct selection of dies, punches, tips or connecting sleeves;
correct location holes formed in places of indentation.
The required contact pressure is ensured by the correct selection of the tool for crimping (punch and matrix) in accordance with the cross-section and grade of the core, and checking it by measuring the depth of indentation after crimping and comparing the obtained value with the value given in the instructions.
Tips or connecting sleeves are also selected according to the cross-section and type of core. Correct placement of holes formed in places of indentation and distances
between them is determined using special tables. Connections and critical branches of single-wire aluminum wires with cores with a cross-section from 2.5 to 10 mm 2 are made in GAO series sleeves, with the maximum total cross-section of the cores of the connected wires being 32.5 mm 2 . Crimping of cylinders we carry out It is done with one indentation when filling them with veins on one side and with two indentations - when filling them on both sides. To connect and terminate wires with a cross-section of more than 10 mm2, sleeves of the TA series and tips of the TA and TAM series are used.
Crimping of aluminum conductors is carried out by two pressings of the tubular part of the tip and four pressings of the sleeve (two pressings of each conductor inserted into the sleeve). Copper conductors are crimped with one indentation in the tip and two indentations in the connecting sleeve. It is prohibited to use tips that do not correspond to the cross-section and design of the cores. The length of the aluminum sleeve and the cylindrical part of the aluminum tip is usually longer than the length of the copper sleeve and tip. With a two-pronged instrument, two indentations are performed in one step, and four in two.
Crimping is carried out using hand pliers, as well as mechanical, pyrotechnic and hydraulic presses using replaceable dies and punches.
Crimping of aluminum cores in GAO series sleeves is performed in a certain sequence:
clean the ends of the cores and the inner surface of the sleeve to a metallic shine and lubricate it with quartz vaseline paste; put a sleeve on the ends of the cores;
if the total cross-section of the cores is less than the nominal one, additional cores are inserted into the sleeve;
crimping is carried out by pressing a single-tooth punch into the sleeve until the locking device of the press jaws is activated or until the base of the punch comes into contact with the matrix (in the absence of a locking device);
insulate the pressed contact connections with polyethylene caps.
Aluminum cable cores are terminated in tubular lugs. To avoid leakage of the cable impregnating composition, the gap in the tip blade is sealed by double-sided counter-pressure with the formation of semicircular grooves in the flat part of the tip.
Single-wire sector aluminum conductors are rounded before insertion into the tip special tool, after which they clean the end of the core, lubricate it with quartz-vaseline paste and make a connection or termination in the usual manner.
The connection of stranded aluminum conductors by crimping is permitted only for cables with a cross-section of no more than 95 mm 2, designed for a voltage not exceeding 1000 V. The connection of stranded aluminum conductors of cables with any cross-section, designed for a voltage of 3... 10 kV and above, as well as with sections more than 95 mm 2 for voltages up to 1000 V should be done by welding or soldering.
For crimping aluminum and copper-aluminum cable lugs of the TA and TAM series, as well as aluminum connecting sleeves of the GA series on aluminum conductors of wires and cables with sections from 16 to 240 mm 2, a universal step device is produced (Fig. 7.8) in two-prong and single-prong versions, and for cores with sections of 120...240 mm, 2 devices UNI-1A and UNI-2A, respectively, in single-tooth and two-tooth versions. With a single-tooth device, crimping of one contact is carried out in two steps using presses RMP-7 and RGP-7, and with a two-tooth device - in one step using presses RGP-7, RMP-7 and PGEP-2.
The reliability of the contact connection is ensured by strict adherence to the crimping sequence: selection of the required standard size of the tip or sleeve in accordance with the cross-section and design of the core being crimped (according to the markings on the tool matrix); stripping the core and the inside of the tip or sleeve and lubricating them with quartz vaseline paste; rounding of sector cores; putting a tip on the end of the core or inserting the ends of the connected wires into the sleeve; performing crimping using a punch and a matrix (the end of the process is determined by touching the side of the punch with the shoulders of the matrix).
The residual thickness at the point of indentation after crimping (indentation depth) is measured with a special tool or a caliper with a nozzle (Fig. 7.9), and the quality of the connection is also checked.
The termination of copper stranded wires with core sections of 1 ... 2.5 mm 2 is carried out by crimping in ring lugs, and the connection is made by crimping with a comb punch and a matrix from a set of manual press pliers. Connection places
Before crimping, wrap with thin copper or brass foil tape.
Termination of copper stranded wires of large cross-sections is carried out in tubular lugs using the method of local indentation. Copper conductors are connected in tubular copper connecting sleeves in the same way as aluminum ones, but without the use of quartz vaseline paste and with less (twice) the number of indentations.
Widely applied new way terminations and connections of cores, insulated wires and cables - multifaceted crimping Manual hydraulic press PGR-20 with a set of tools that simultaneously performs hexagonal compression and local indentation. This crimping method ensures reliable electrical contact of aluminum conductors of wires and cables with cross-sections from 16 to 240 mm 2.
Due to the widespread use of wires and cables with single-wire sector aluminum conductors of large cross-sections, a new termination method is being introduced, which is simple and economical - pressing. Using a special powder action press, cores with sections from 16 to 95 mm 2 are terminated, changing punches and dies accordingly. Press of indirect action, i.e. a punch, moving under the action of powder gases, strikes a vein located in the matrix, and gives its end the shape of a finished tip in one shot. Volumetric pressing of the tip from the sector monolithic cable core is carried out using a PPO-95m pyrotechnic press.
When terminating a single-wire conductor by pressing out the tip, it is necessary to seal the cut point of the conductor insulation, which is done in the same way as when using conventional ferrules.
Currently, domestic factories produce cables of the ASB and ASBG brands new design- with aluminum combined sector conductors with sections of 120, 150 and 185 mm 2. The combined core is a continuous sector with one layer of wire along its perimeter.
The connection and termination of such cables is made by crimping using two local indentations without preliminary rounding of the ends of the cores and with their preliminary rounding with a special tool. The latter is advisable for a large number of connections and terminations concentrated in one place.
Welding is the formation of a permanent connection of parts by their melting or joint deformation.
When connecting and terminating aluminum conductors by welding of any kind, it is necessary to perform certain General requirements: protect individual wires from burning; protect insulation from overheating and fire damage; prevent aluminum from spreading;
protect joints and ends from corrosion, and aluminum from oxidation.
Welding is carried out only from the ends of the cores in a vertical or slightly inclined position. To remove heat, special coolers are used with a set of replaceable copper or bronze bushings installed on the exposed areas of the cores. To avoid spreading of aluminum, welding is performed in special forms, and the exits of the core from the mold are sealed with corded asbestos. When gas and thermite welding, disk steel screens are used to protect the insulation from the direct action of the flame. The side surfaces of individual wires must be free of traces of melting, burns and shells, i.e. in the monolithic part of the connection their cross-section should not decrease.
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To remove the aluminum oxide film from the surface of the welded conductors, fluxes of the VAMI and AF-4a brands are used. The completed connections and ends are cleaned of flux and slag residues, washed with gasoline, coated with moisture-resistant varnish and insulated with tape or a plastic cap.
Electric welding of single-wire aluminum conductors with a cross-section of up to 10 mm 2 is performed using pliers with a carbon electrode without flux and with flux. In the first case, the fusion of the ends of the cores into a monolithic rod is carried out in a holder heated by carbon electrodes; in the second case, the melting of the ends of the cores (preliminarily cleaned, rounded and coated with flux) is carried out directly with a carbon electrode without a holder until a ball of molten metal forms at their ends. In both cases, the source of electricity for welding is a soldering transformer with a power of 0.5 kVA with a secondary voltage of 6, 9, 12 V.
Electric welding of twisted single-core wires, both aluminum and copper with aluminum (with a total cross-section of up to 10 mm2), is performed without the use of flux using a stationary semi-automatic welding machine VKZ-1, which stops welding at the moment the wires melt to a given length. The productivity of this device is 2 - 3 welding per minute.
Electric welding stranded wires and cables, contact heating is carried out using a carbon electrode and a welding transformer with a secondary voltage of 6... 12 V.
There are three types of welding transformers.
In transformers with normal magnetic dispersion (Fig. 7.10, a) primary and secondary<в 2 и реактивная со р обмотки размещены на основной части 1 магнитопровода. Подвижная же часть 2 магнитопровода, меняя регулируемый зазор 8, изменяет индуктивное сопротивление реактивной обмотки, включенной последовательно с нагрузкой. Чем больше зазор, тем меньше индуктивное сопротивление обмотки и больше сварочный ток / 2 . Подвижная часть магнитопровода перемещается с помощью электропривода с дистанционным управлением. Такие трансформаторы выпускаются на нормальные сварочные токи от 500 до 2000 А.
In transformers with moving coils (Fig. 7.10, b), one of the windings, usually the secondary one, is mixed with 2. As the primary and secondary windings come closer together, the magnetic coupling between them increases, the load current increases, and vice versa. Such transformers are designed for welding currents from 150 to 600 A.
In the transformer, the diagram of which is shown in Fig. 7.10, c, a rotary magnetic shunt 3, located between the secondary Yu2 and the primary windings, short-circuits part of the magnetic flux created by the primary winding, i.e. The smaller the gap between the shunt and the main part 1 of the magnetic circuit, the less flux passes through the secondary winding and the less welding current /2.
The connection of stranded aluminum conductors is carried out in two steps: first, the ends of the connected conductors are fused into a monolithic rod, and then they are welded in an open form. When terminating, the end of the core is inserted into the tip sleeve and fused with the upper protruding part of the sleeve into a common monolithic rod. Electric welding by contact heating is mainly used for connections and branches of small-section aluminum wires, especially on bench preparation lines for lighting electrical wiring. When terminating aluminum conductors of wires and cables, the contact heating method is not used, since it is low-productivity and requires the use of cast aluminum tips.
For welding stranded conductors, the following is required: coolers with replaceable bushings for conductors of different sections and wires for connection; open molds (steel or carbon for butt welding of cores or detachable for fusing cores into a monolith); filler rods (made of aluminum or copper with a diameter of 3... 8 mm); asbestos cord (or sheet asbestos 2...3 mm thick) for sealing molds; fluxes (to coat the surface of the cores being welded in order to remove metal oxide formed during the welding process).
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In addition to electric welding with a carbon electrode, there is welding in a shielding gas environment. For example, the termination of aluminum conductors with a cross-section from 16 to 240 mm 2 is carried out in tips of the LLIAC series, which are welded to the conductor using a semi-automatic PRM type or manual argon-arc welding with a non-consumable (tungsten) electrode, without the use of fluxes. In this case, argon of the first grade A is used as a protective gas against atmospheric oxygen, and filler wire made of aluminum alloy grade SvPK5 is used to replenish the weld pool with metal.
A reliable way to connect aluminum wire and cable cores is gas welding, in which the connection and termination of aluminum wire cores is carried out in a flame of flammable gases: acetylene, gasoline-oxygen mixture or propane-butane. The propane-butane mixture differs from other gases in its ability to liquefy at low pressures, as well as high calorific value. The low internal pressure of the liquefied propane-butane mixture allows it to be stored and transported in small, thin-walled cylinders.
The connection of cores of aluminum wires and cables with sections from 16 to 240 mm 2 can also be performed by propane-oxygen welding in steel forms using a multi-flame burner, where the combustible gas is propane and the oxidizer is oxygen. In this case, flux of the VAMI brand and filler welding wire of the SvAK5 or SvA5S brands with a diameter of 2 and 4 mm are used, depending on the cross-section of the cores.
Intensive heat dissipation into the surrounding space during gas welding (especially with multi-flame propane-oxygen welding) necessitates enclosing the welding zone with asbestos screens installed close to the ends of the molds. Coolers are fixed to the exposed areas of the cores behind the screens, while the insulation of the welded core behind the cooler is protected with sheet asbestos at a distance of at least 100 mm. PVC tubes are put on the remaining cores and shielded with a sheet of asbestos cardboard.
The possibility of gradually withdrawing the torch upon completion of welding makes it possible to fill the shrinkage cavities in the joint that occur during crystallization of the metal with the filler material melted to them. At the same time total time welding should be as minimal as possible to avoid overheating of the cores and damage to the conductor insulation.
Gas welding, like electric welding, is carried out in two steps: first, the ends of the stranded cores are fused into a monolithic rod, and then the monolithic cores are welded together. When terminating the cores, they are melted with a tip top part its sleeves (rim) together with the end of the aluminum core.
For gas welding, sets of tools and accessories are produced, for example, for propane-air welding - the NSP-1 set, consisting of two cylinders, a gas-air torch and a rubber hose with a tap. Propane-butane torches are successfully used when making connections between the lead cable sheath and the body of lead couplings and welding the grounding of cable sheaths. Twists of aluminum wires with sections up to 10 mm 2 in boxes are welded using a propane-butane torch with a highly directed flame.
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causing irritation and inflammation of the mucous membrane of the nasopharynx and eyes, as well as headache, therefore, those working with this gas must strictly follow safety rules: work with a propane-butane burner only with the ventilation turned on, and in cable tunnels and wells - in the presence of an observer.
Liquefied propane-butane, if it gets on the body, can cause frostbite, so it must be quickly washed off with water.
Soldering and compression connection. The technological process of forming a permanent connection of metal parts by heating and filling the gap between them with molten solder, which after crystallization (solidification) forms a strong mechanical junction (seam), is called soldering. During the soldering process, mutual dissolution and diffusion of the solder and the base metal occur, which ensures a certain mechanical strength of the joint after solidification. Unlike welding, when soldering, the base metal of the parts being joined does not melt, since the melting temperature of the solder is always lower than the melting temperature of the metals being joined. The parts to be soldered are heated with a soldering iron, a gas burner, in ovens, and high-frequency currents.
To make contact connections, welding and crimping are mainly used. Soldering is used as the main method only when making branches of copper conductors with sections of 16... 185 mm 2. In other cases, soldering is used only when welding or crimping is impossible.
Soldering has a simple technology, but it is very labor-intensive. Subject to all technological requirements solder ensures high adhesion of the materials of the connected cores, which is facilitated by the use of fluxes, which, in combination with oxides, form slags and prevent oxidation, and also increase the fluidity of solders.
Soldering is performed with a propane-butane torch or gasoline blowtorch using the following solders: for aluminum conductors - tin grade A (tin - 40%, zinc - 58.5%, copper - 1.5%) with a melting point of 400...425 °C, zinc-aluminum grade TsA-15 (zinc - 85%, aluminum - 15%) with a melting point of 550...600 ° C and zinc-tin grade TsO-12 (tin - 12%, zinc - 88%) with a melting point of 500...550 "C, and for copper - tin-lead grade POSSu-35-0.5 (tin - 34...36%, antimony - 0.2...0.5%, the rest is lead) with a melting point of 245 °C or grade POSSu -40-0.5.
Soldering paste (10 weight parts of rosin, 3 weight parts of zinc chloride and 1 weight part of water or ethyl alcohol), rosin, solder fat and stearin. When terminating aluminum conductors, flux of the VAMI brand is used (potassium chloride - 50...55%, sodium chloride - 30...35% and cryolite grade K-1 - 20...10%), and for connecting aluminum cable conductors in couplings - AF-4A grade flux (potassium chloride - 50%, sodium chloride - 28%, lithium chloride - 14%, sodium fluoride - 8%). The melting point of both fluxes is about 600 °C.
Solders, which are pure metals or alloys and are used as binders in soldering, must have a melting point significantly lower than the metal parts they connect. Solders are divided into low-melting and refractory. Low-melting (soft) solders have a melting point below 500 °C, and refractory (hard) solders above 500 °C.
In solder brands, the letter P, located in the first place, denotes solder, the letters behind it indicate the name of the element (O - tin, Su - antimony, C - pig
6.1.1. General provisions for cutting and preparing cables for installation. This section does not discuss in detail technological processes preparation of cables for splicing and restoration of the sheath, but only the main stages for cables with polyethylene sheaths are given. Detailed description individual operations of preparing the cable for installation are given in paragraphs. 11.27-11.35 “Guidelines for the construction of linear structures local networks connections." Moscow 1996 6.1.1.1. Clean the cable sheaths from the channels exiting from dirt. 6.1.1.2. After making sure that the shells and cores are in good condition (items 11.18 – 11.21 of the “Manuals...”), temporarily secure the cables to be mounted on the well consoles with wire bands. 6.1.1.3. Select a coupling in accordance with the type, capacity and diameter of the cable being installed, guided by technical specifications for couplings, as well as tables given in the instructions for the relevant types of work and clause 11.28 of the “Manual...”. 6.1.1.4. Determine the location of the coupling and, based on its dimensions, at the ends of the mounted cables, mark the places where the sheaths are cut. The distance between the shell cuts (working area) should be selected based on the tables given in the instructions for the relevant types of work. In this case, the minimum length of the ends should be 1.5 times greater working area(Clause 11.29. “Guidelines...”).
6.1.1.5. Strip the cable sheath with a knife on both sides of the stripping point mark at a distance of 60-80 mm (section 11.30. “Manuals...”).
6.1.1.6. Using a knife, use a knife to make a circular cut and one or more longitudinal ones at a distance of 10-15 mm according to the marks on the cable sheath. Bend the sheath in the area from the circular cut to the end of the cable and remove it (Section 11.31. “Manuals...”).
6.1.1.7. If the cable core has a hydrophobic filling, clean it in accordance with section 6.2. of this instruction.
6.1.1.8. Slide the coupling parts onto the ends of the cables.
6.1.1.9. Wrap the internal protective coverings (waist insulation and screen tapes) into rolls and temporarily secure them together with the longitudinal screen wire on the cable sheath near the cut (section 11.32 of the “Manual...”).
6.1.1.10.Restore screen continuity in accordance with section 4 of this manual.
6.1.1.11. Wrap the ends of cables with polyethylene and polyvinyl chloride sheaths with 4-5 turns of PVC tape.
6.1.1.12. Disassemble the cores of the cables being installed into bundles and half-strands: in bundle-twisted cables, tie each bundle with waxed thread at the cut of the sheath and tie it to the cable sheath in the reverse order of their installation; in twisted cables, disassemble the core into half-strands. Why should each curl, starting from the top, be disassembled into two bundles: near and far. Select approximately 60% of pairs or fours for the near beam, and 40% for the far beam. The selected groups are also tied to the cable in the reverse order of their installation.
6.1.1.13. Operations to restore the belt insulation and sheaths of mounted cables should be performed after installing the cores in accordance with paragraphs 11.62-11.65 of the “Manual...” and the corresponding instructions for these types of work.
6.1.2. Cleaning cable cores from hydrophobic filler. This section discusses the process of cleaning cable cores from hydrophobic filler using a remover such as Scotchcast™ 4413.
6.1.2.1. The kit for removing hydrophobic filler (wash) includes:
Plastic sleeve for rinsing the cable core;
Cleaning remover of hydrophobic filler;
Plastic bags to protect the sleeve from punctures by cable cores;
Protective gloves to protect your hands when washing.
In Fig. 6.1.2.1. All listed components are shown.
6.1.2.2. Select the standard size of the kit. In table 6.1.2.1. Provides all the necessary information to select the right kit.
Data on the number of cable ends to be flushed are given in Table 6.1.2.2.
In addition to those specified in clause 6.1.2.1. components required to remove hydrophobic filler:
Scotch™ 88T vinyl tape;
Wiping rags.
6.1.2.3. Cut the threads or ribbons separating the elementary
bunches. To prevent them from breaking, twist the bundles at the ends and fluff out the strands if possible. Use a dry cloth to partially remove the hydrophobic filler from the cable core.
6.1.2.4. Dress protective gloves. Open the bag with liquid to remove the hydrophobic filler 4413. To prevent punctures by the ends of the wires of the plastic sleeve, place a small plastic bag on the end of the cable core (Fig. 6.1.2.2).
6.1.2.5. Cut off the upper part of the sleeve with the wash and insert the end of the cable into it (Fig. 6.1.2.3). The sleeve should extend 100 mm onto the cable sheath.
6.1.2.6. By squeezing the sleeve, if possible, release the air from it. Wrap the end of the sleeve tightly on the cable sheath with several layers of 88T vinyl insulating tape. (Fig. 6.1.2.4).
6.1.2.7. Using rinsing movements, wash off the hydrophobic filler from the cable core (Fig. 6.1.2.5). The duration of washing for cables with a capacity of up to 200 pairs is 5-7 minutes, for cables with a capacity of over 200 pairs - 10-12 minutes.
6.1.2.8. After the specified time has elapsed, place the end of the cable and the sleeve in a vertical position for 1-2 minutes and allow the wash to drain into bottom part sleeves (Fig. 6.1.2.6).
6.1.2.9. Unwind 88T vinyl insulating tape from the end of the sleeve, remove the sleeve and plastic bag from the end of the cable. Place the cable core in a vertical position and wipe with a dry cloth.
The multi-core telephone cable of the Chamber of Commerce and Industry has remained the main one for laying city telephone networks for several decades.
The wide range of this cable allows it to be used in all sections of the telephone communication line and laid in open ground, collectors, on supports, inside and outside buildings.
The ten-pair TPP is used to connect network subscribers to the main telephone line. To connect the cable to the plinth in the telephone distribution box, a certain order of color numbering of pairs in the cable is used.
Specialists of the LLC " Cable Center» it is recommended to use only certified cable for installation famous manufacturers. Otherwise, you may encounter non-standard colors of core insulation and mismatched color numbering of pairs.
What you need to know about the structure of the TPPep cable
Currently, the telephone network uses shielded TPPep cable as the main city cable.
Single-wire copper insulated cable cores are twisted in pairs with a small layer pitch. Continuous polyethylene insulation of pair conductors differs in color and corresponds to the standard color counting of pairs.
Pairs are twisted into elementary bundles consisting of 5 or 10 pairs. The elementary bundle is fastened with a synthetic thread. In addition, it has a colored thread that distinguishes the bundles from each other. The TPP 10x2x0.5 core consists of one ten-pair elementary beam.
Belt insulation made from PET tapes is applied over the core, which preserves geometric shape and serves to isolate the cores from mechanical and thermal effects. A 0.1 mm thick film screen made of aluminum foil applied to a polymer tape is placed on top of the waist insulation. An uninsulated contact copper wire is laid under the metal layer of the screen.
Top layer of cable -protective shell made of high pressure polyethylene.
On the website of the dealer company "Cable-Center" you can purchase a certified TPPep 10x2x0.5 cable at a factory price.
Color count (wiring) of TPP cable 10 pairs
The order of wiring a ten-pair telephone cable on a plinth is determined by the standard, in which each pair of conductors is assigned a number corresponding to the color combination of the pair’s cores.
Distribution boxes that are installed in the building allow you to connect a multi-pair trunk communication cable TPPep with a single-pair subscriber cable TPP. With its help, the PBX is connected to the telephone socket in the apartment.
Before cutting the cable, remove the sheath, belt insulation and screen from it with a special tool at a distance of 1.5 m from the edge and fasten it with electrical tape. Then they pull out one pair at a time and insert it into the plinth.
Color counting of the Chamber of Commerce and Industry in accordance with the standard, taking into account that the counting on the plinths is started from “0”:
- First five pairs- white-blue, white-orange, white-green, white-brown, white-gray.
- Second five pairs- red-blue, red-orange, red-green, red-brown, red-gray.
There is no need to remove the insulation from the conductors, since the contacts of the plinths contain knives that cut it and provide an electrical connection.