power cable

Damaged ABC cable sheath may not be a quality problem

by

In the severe cold in winter, many construction workers will find such a problem when laying and installing Aerial Bundled Cable: ABC cable products with good quality usually have some hardening of the wire body and peeling off of the insulation coating. In view of these phenomena, many construction workers think that the wire and cable products themselves have quality problems, but in fact, the insulation of the cable products is damaged or peeled off, which is not necessarily the product quality problem. Next, let’s take a look at the reasons and preventive measures for the damage and fall of the cable sheath.

  1. The cable sheath is damaged or peeled off, which may be caused by the cold weather in winter. The outer skin of wire and cable products is mostly ordinary plastic (PVC) or rubber. When they are in a sub-zero environment, they will become hard, especially in the north. In winter, the outdoor temperature is often below zero, and the surface temperature may be more Low, if the wire and cable product is placed outdoors or directly on the ground, the entire wire and cable product line will become hard and brittle, causing the outer skin to fall off and be damaged under a slight external force.
  2. Can (ABC) HD 626 S1 Standard sheath be used if it is damaged?
    Try not to use it. The reason is: the sheath of the cable plays a protective role. If the cable is used directly without the protection of the sheath, it will soon cause leakage. Therefore, try not to use the cable sheath if it is damaged or falling off. If you must use the cable, you need to Take some protective measures, such as: for outdoor cables, you need to use waterproof insulating tape first, and then use heat shrinkable tubing, just fine; if it is used for high-voltage lines, you need to deal with the damaged insulation skin, generally high-voltage Wrap a certain number of turns with tape to make it fully meet the 10KV high-voltage cable insulation requirements; for severely damaged cables with partial discharge phenomena, a section of the partially damaged high-voltage cable should be discarded, and it should be done in a partially damaged place. High pressure connector.
  3. Measures to prevent damage and fall off of the cable sheath in winter:
    (1) When the cable is shipped out of the factory, warm and protective measures are required, such as: use enclosed transportation tools to prevent the product from being directly exposed; padded the product with a layer of soft cushion, such as bedding or other soft foam. (2) Cable storage: When arriving at the destination or the construction site, the product supplier should send personnel to supervise to prevent rough operations when the product is unloaded; try to store the product indoors, and at the same time lay a place on the surface of the storage. Layer isolation layer, such as wood, bedding, foam, etc., to prevent the product from freezing and damp.(3) Cable laying: you should choose to work under the condition of warmer temperature in the middle and afternoon, or do some protection for the cable, especially when laying the cable through the pipe, make sure that the inside and outside of the pipe are smooth in advance, so as not to scratch the wires. .

Well, the above is the introduction about the “causes and preventive measures of cable sheath damage and shedding”, I hope everyone can understand.

Matters needing attention in the production of ACSR Cable

by

1. Greasy dirt on the wire surface
Overhead ACSR cables used for overhead transmission lines are often questioned by customers or even returned due to surface quality problems. This phenomenon is mainly caused in the drawing process. The main reasons are as follows:
(1) The size of the finished wire drawing die is too large, the compression is relatively small, and the working area of ​​the wire drawing die is short, which is not enough to remove the oil on the surface of the wire;
(2) The temperature of the lubricating grease is too low, the viscosity is large, and it is not easy to play, causing the drawing oil to adhere to the surface of the aluminum wire;
(3) The thread rubbing felt at the exit of the finished mold is too dirty;
(4) When stranding the wire, the stranding machine body or the traction wheel is too dirty;
(5) There is too much water under the traction wheel.
For the above reasons, in order to avoid the generation of oil stains on the wire surface, select a suitable wire drawing die and adjust the temperature of the lubricating grease during wire drawing; frequently replace the wire rubbing felt, and keep the stranding equipment and mold clean and free of oil when stranding the wire.


2. The wire surface is scratched
Since there are sharp metal objects in the wire drawing equipment and  ACSR Cable drawing die or the wire stranding equipment and the wire stranding die, it is easy to cause surface scratches when the wire is drawn or the wires are stranded. This kind of defect firstly affects the surface quality of the wire, and secondly, corona occurs due to the unevenness of the conductor when the wire is running. Therefore, once the surface scratches are found, the cause should be investigated immediately from the equipment or mold.
3. Wire scratches
Continuous scratches on wires are the most common cause of corona, and corona is one of the most important causes of power loss in power systems. In order to avoid the occurrence of wire scratches, the following aspects should be controlled in production: firstly, consider the conductor itself. First, ensure that the aluminum rod is not damp. The aluminum rod is damp, causing aluminum chips to stay in the working area of ​​the drawing die hole, and the lubricating oil cannot be used. All enter the work area, resulting in the drawn aluminum wire is not round and not smooth. Second, ensure that the drawing oil is clean and free of moisture. In the process of drawing, the drawing oil is in a high temperature state when it enters the work area from the lubricating area. If it contains a certain amount of moisture, the lubricating oil will be diluted and the lubricating effect will be greatly reduced, resulting in wire scratches and aluminum wire breakage.


Secondly, from the perspective of production, the following issues should be paid attention to:
In the drawing process:
(1) Check whether the mold of the wire drawing machine is placed accurately;
(2) Check whether the drawing drum has a groove after friction, and whether there is a crimping phenomenon;
(3) Check whether the surface finish of the lubrication area of ​​the drawing die meets the requirements, and whether there is blockage by aluminum chips.
In the stranding process:
(1) Check the sensitivity of the top of the spool;
(2) Check whether the tension of the spool is uniform;
(3) Check whether the single wire is slightly crimped or the wire is uneven;
(4) Check whether the single wire is in the groove of the guide wheel during twisting.
4. Loose wires and serpentine bends
(1) Adjust the pay-off tension of the wire reel when twisting the wire. The tension depends on the accumulation of experience in normal work. Generally, experienced operators should be able to adjust the tension to the appropriate requirements;
(2) When selecting the parallel mode first, the diameter of the parallel mode is required to be 0.3-0.5mm smaller than the outer diameter of the stranded wire;
(3) Adjust the back-twisting device to make the single wire “S” before twisting, so as to eliminate the internal stress generated by the single wire during the twisting process;
(4) Minimize the number of stops during the stranding process. It is best to produce the same stranded wire at the same fixed speed to prevent uneven speeds or parking/driving.
(5) Check in advance to use the steel core for stranding to ensure that there is no looseness; when the wire is stranded, the steel core should maintain a sufficient constant pay-off tension.

Precautions for household wire installation

by

In home decoration, circuit engineering is the most important, and home circuit belongs to concealed engineering, which is related to people’s quality of life and living standard in the future. Therefore, we must pay attention to circuit problems in decoration to avoid potential safety hazards. Next, Guoyou AAC Cable will share the relevant knowledge of family wire laying to protect the safety of family electricity.

1、 Flame retardant wires shall be selected
In modern families, there are too many household appliances and heavy wire load, which is easy to cause fire accidents. In these aspects, flame retardant wires can meet the power demand of families. At the same time, in case of fire hazard, flame retardant wires can effectively control the spread speed of fire, avoid greater losses caused by the fire of combustibles around wires, and strive for more time for people to evacuate from the fire site to minimize the loss of fire injury.

2、 Use wires of different colors
Color classification shall be done well when laying family lines, and it is more convenient for later maintenance. According to national regulations, red, yellow and green represent live wire, light blue is used for zero wire, and yellow and green are used for ground wire. In future maintenance, electricians can distinguish live wire and zero wire through the color of wires, which is convenient for construction and is also very important for household electricity.
3、 Wire laying and pipe sleeve
According to the ACSR Cables laying regulations, the wire must be protected by insulating sleeve during the laying process, and the joint shall not be exposed. Some irresponsible construction teams will directly bury the wires in the wall without casing protection. This treatment leads to the exposed wire joints, which are easy to be damaged by external forces, so as to reduce the service life of the wires and bury potential safety hazards for people’s life.

Unqualified ABC Cables laying will not only affect our use, but also directly affect our life safety. Choosing a high-quality wire product can reduce the risk from the source. Guoyou high-end wire has excellent performance in high temperature resistance, moisture resistance, durability, energy saving and environmental protection, which is different from ordinary household wires, With professional environmental protection and flame retardancy, consumers are more safe and assured to use. The above is the relevant knowledge of family wire laying. I hope it will be helpful to you

How to prevent cable from fire due to conductor overload

by

During the operation of wires and AAC Cables, they will heat due to the existence of resistance. The resistance of the conductor is generally very small, and its heating power can be expressed by the formula q = I ^ 2R. Q = I ^ 2R shows that for a section of conductor in actual use (r has been basically constant), the greater the current passing through the conductor, the greater the heating power; If the electric flow is constant, the heating power of the conductor is also constant. The heat released during operation will be absorbed by the conductor itself, resulting in the increase of conductor temperature. Although the conductor keeps absorbing the heat released by current work during operation, its temperature will not rise indefinitely. Because the conductor is absorbing heat and constantly releasing heat to the outside world, the facts show that the temperature rises gradually after the conductor is powered on, and finally the temperature is constant at a certain point. At this constant point, the heat absorption and release power of the conductor are the same, and the conductor is in thermal equilibrium. The ability of conductor to withstand high temperature operation is limited, and operation beyond a certain maximum temperature will be dangerous. This maximum temperature naturally corresponds to a maximum current. If the conductor exceeds this maximum current, it is overload. The overload of the conductor directly leads to the temperature rise of the conductor itself and its nearby articles. Temperature rise is the most direct cause of this kind of fire.


Overload destroys the insulation layer between double stranded conductors, causing short circuit, burning equipment and fire. The double strand conductors are separated by the insulating layer between them. Overload softens and destroys the insulating layer, resulting in direct contact between the two strands of conductors, causing short circuit and burning the equipment. At the same time, the high temperature generated by large current at the moment of short circuit causes the line to catch fire and fuse, and the generated molten beads fall to combustibles to cause fire. Overload temperature rise can also directly ignite nearby combustibles. The heat transfer of overload conductor increases the temperature of nearby combustibles. For combustibles with low ignition point nearby, it is possible to ignite them and cause a fire. This danger is particularly prominent in warehouses for storing inflammables and buildings with easy and combustible decoration.
Overload also puts the connection in the line under overheated conditions, which accelerates its oxidation process. Oxidation causes a thin layer of oxide film that is not easy to conduct electricity at the connection point. The oxide film increases the resistance between the contact points, resulting in ignition and other phenomena, resulting in fire.
So, how to prevent fire caused by overload of wires and ACAR Cables?
1. In the process of line design, the capacity of the site shall be accurately verified, the possibility of new capacity in the future shall be fully considered, and the appropriate type of conductor shall be selected. For large capacity, thicker conductor shall be selected. Line design and reasonable type selection are the key steps to prevent overload. If the design and selection are improper, it will leave congenital hidden dangers that are difficult to rectify. Some small projects and places are not carefully designed and selected. It is very dangerous to choose and lay lines at will. The bearing capacity of the original line shall be fully considered for new electrical appliances and electrical equipment. If the original line does not meet the requirements, it should be redesigned and reconstructed.


2. The line shall be laid by qualified electricians in accordance with relevant specifications. The laying conditions of the line directly affect the heat dissipation of the conductor. Generally speaking, the line laying shall not pass through inflammable and combustible materials and stacking, which will lead to poor heat dissipation of the conductor, heat accumulation, the possibility of igniting the surrounding combustible materials, and increase the risk of fire under overload; The lines laid in the decoration ceiling of public entertainment places shall be protected by steel pipes to separate the ceiling from the line. Even if there are molten beads under overload, short circuit and other conditions, they will not fall, so as to avoid fire.
3. Strengthen power management, avoid random wiring and grounding, and use mobile sockets carefully. Random ACSR Cables, random grounding and the use of mobile sockets are actually adding electrical equipment to a certain section of the line, increasing the amount of current, which may cause overload. The jack of mobile socket is obviously more than the fixed socket on the wall. If too many electrical equipment are used on the mobile socket, the original line must be difficult to bear. For high-power equipment and electrical appliances, separate lines should be set, and mobile sockets should not be used as wiring sources.


4. Speed up the renewal and transformation of old lines and eliminate potential fire hazards. Due to the long service life of old enterprises, old residential areas and other units, many lines have aged and exceeded the service life. Even if the current carrying capacity of some lines is small, it is difficult for aging lines to bear such current carrying capacity, and it also has the risk of overload. Especially in the old residential areas, the lines have long been aging, but with the improvement of people’s living standards and the increase of household appliances, their power consumption is still increasing year by year, which is really worse. For old lines, timely supervision and coordination shall be carried out to promote their rectification as soon as possible, so as to eliminate potential fire hazards and ensure safety.

Harm and Countermeasures of wire joint heating

by

The phenomenon of wire joint heating is generally manifested in that there is peculiar smell around the wire joint, which can be smelled. This is because the heat of wire joint makes the outer insulation layer smell; Secondly, the ACSR Cables joint is smoking, red, the outer insulation layer is black, fire, or even broken. What are its hazards, causes and countermeasures?

1. Harm
Hot wire connection will not only cause a lot of power loss, but also seriously affect the normal operation of electrical equipment. At least, the working current in the line will increase and the service life of electrical equipment will be shortened. At worst, it will suddenly interrupt the ongoing production, scientific research, medical surgery and other activities, and lead to fire and electric shock accidents, resulting in incalculable losses.

2. Cause
(1) The connector is not tightened during equipment installation and repair. When the current passes through, it may generate heat, even redness, smoke, fire and disconnection. ABC Cables, switches and electrical appliances are connected through wire posts. Due to careless construction, no washer is added on the terminal post and the Gong cap is not tightened, which will also increase the contact resistance. For example, in a hotel, because of this reason, the conductor heated and melted, and the molten beads fell on the cardboard box below, causing a fire.
(2) The connector will also loosen after long-term operation. Some joints are of good quality during installation, but they will become loose due to thermal expansion and cold contraction or long-term vibration. For example, for copper aluminum joints in long-term operation, if there is no silver plating or tin hanging on the contact surface, the contact surface produces serious electrochemical corrosion and generates oxide film, which increases the resistance at the joint and is very easy to become a hot spot.

(3) For contacts with small current, the current increases suddenly due to the sudden change of the system, resulting in contact heating;
(4) In case of short circuit fault of the system, the over-current makes the contact with insufficient capacity or defective contact ignite instantly, etc.
Therefore, the contact heating is mainly caused by the increase of contact resistance.
3. Countermeasures
If the connector is well connected, the heating of the connector is prevented, and the heating problem of the AAAC Cable connector will not appear, so it does not need to be handled. Therefore, the wire joint shall be firm, tight and beautiful without overlap, bending, crack and concave convex; The mechanical strength of the joint shall not be less than 80% of the mechanical strength of the conductor; The insulation strength of the joint shall not be lower than that of the conductor. During installation and maintenance, the joints of wires shall be reduced as much as possible. Conductors with too many joints shall not be used. For joints of movable lines and outdoor lines, special attention shall be paid to the provision that only one joint is allowed between two adjacent wire stems.

What is the economic optimization of cable section?

by

The International Electrotechnical Commission Standard IEC 287-3-2 / 1995 puts forward the viewpoint of economic optimization of cable size, that is, conductor section: the selection of cable conductor section should consider not only the initial cost of cable line, but also the power loss cost of AAAC Cable during its economic life, which should comply with the principle of minimizing the sum of the two costs. Expressed mathematically, i.e
CT=CI+CJ


Where CT is the total cost; Ci is the initial investment cost; CJ is the present value of Joule loss during the economic life of N years, that is, it is converted into present value according to the discount rate (I). The economic optimization of cable conductor section is called “economic conductor section”, which can be obtained by calculation.
The section determined according to the maximum allowable temperature and current carrying capacity of cable insulation is actually the minimum allowable conductor section. At this time, only the initial investment is calculated without considering the conductor loss cost during the economic life of the cable. If the conductor section is increased, the line loss cost is reduced and the initial investment is increased. However, the initial investment increased by increasing the conductor section can be compensated from the reduced ACSR Cable loss during long-term operation, so as to reduce the total cost of power supply and improve the economic benefits of the power sector.
Using economic conductor section, the cable operating temperature is much lower than the maximum allowable temperature of cable insulation, which can prolong the service life of cable line and improve the safety of cable power supply.
IEC 287-3-2 / 1995 points out that the temperature difference between the operating temperature of the cable and the average ambient temperature shall be taken as 1 / 3 of the temperature difference between the maximum allowable temperature of the cable and the average ambient temperature, i.e


For example, the maximum allowable temperature of XLPE cable is 90 ℃, and if the average ambient temperature is 24 ℃, its operating temperature should be
℃
The cable section meeting this operating temperature is in line with the principle of economic optimization. According to the calculation, the section of the economic conductor shall be enlarged by 2 grades than the section standard determined by the maximum allowable temperature. For example, if the section determined according to the maximum allowable temperature is 120, the economic conductor section should be 185.

Causes of appearance defects of five kinds of rubber sheathed cables

by

In the production process of rubber sheathed AAC Cable, there are often appearance defects, such as unsmooth surface; Clinker particles (early vulcanized rubber particles) or impurities on the surface; Scratch and scratch on the surface of wires and cables; Surface collapse; There are hemp patterns on the surface.

The following are five common causes of appearance defects of rubber sheathed ACSR Cables:
1. The die sleeve bearing line is too long or too short, the die opening is not smooth and the hole diameter is too large; Low head, die or body temperature; Low plasticity of rubber may lead to unsmooth surface of rubber sheathed cable.
2. The supplied rubber is not clean and contains impurities; The scorch time of rubber is too short; The temperature of rubber extrusion body, head or die is too high; The rubber flow in the head is not smooth, and there is a dead corner of rubber retention; Unsmooth screw and viscose may lead to clinker particles (early vulcanized rubber particles) or impurities on the surface of rubber sheathed cable.
3. The die sleeve is not smooth and has no chamfer; Impurities or clinker particles block the die mouth; Abrasion of dragging pipe in vulcanization pipe; The small aperture of the sealing rubber gasket at the outlet of the vulcanization pipe may cause scratches and scratches on the surface of the rubber sheathed cable.
4. The hole diameter of die sleeve is too large; The gap between the outer strands and monofilaments of the conductive core is too large, and the outer diameter of the cable core is uneven; The rubber has small plasticity and poor viscosity; Impurities in rubber; Small mold distance and pressure may cause the surface collapse of rubber sheathed cable.
5. The hole diameter of die sleeve is too small; Insufficient rubber extrusion and insufficient filling of wire core gap; Conductive core or cable core jumper; Short distance between molds may lead to twist on the surface of rubber sheathed cable.

Rubber sheathed cable is a kind of soft and movable cable with multi strand fine copper wire as conductor and wrapped with rubber insulation and rubber sheath. Generally speaking, it includes general rubber sheathed flexible cable, electric welding machine cable, submersible motor cable, radio device cable and photographic light source cable.
Rubber sheathed cables are widely used in various electrical equipment, such as mobile power lines for daily appliances, electric machinery, electrical devices and appliances. At the same time, it can be used under indoor or outdoor environmental conditions. According to the external mechanical force on the cable, the product structure is divided into light, medium and heavy. There is also appropriate connection on the section.
General light rubber sheathed cables are used in daily electrical appliances and small electric equipment, which are required to be soft, lightweight and good bending performance;
Medium sized rubber sheathed cables are widely used in agricultural electrification except for industrial use;
Heavy duty cables are used in such occasions as port machinery, searchlights, large hydraulic drainage and irrigation stations in domestic industry, etc. This kind of products have good universality, complete series specifications, good and stable performance.
Waterproof rubber sheathed cable and submersible pump cable: mainly used for supporting submersible motor, with models of JHS and JHSB.
Cables for radio devices: now we mainly produce two kinds of rubber sheathed ABC Cables (one shielded and one unshielded), which can basically meet the requirements. The models are wyhd and wyhdp.
Photographic cable products: with the development of new light sources, they have small structure and good performance, meet the needs of indoor and field work, and gradually replace some old products with heavy weight and poor heat resistance.
Operation method:
1. Set the temperature and time according to the vulcanization system of the compound
2. Wipe and wash the repair place with rubber and ink diluent, especially the joint shall be fully treated.
3. Cut the repair rubber properly according to the size of the gap, and pay attention not to be too much or too little,
4. Plug the cut rubber in the gap, and pay attention that the rubber shall not be higher than the circumference of the wire.
5. Wrap it with high temperature resistant PP tape. And put it into the tubular die cavity slightly smaller than the wire diameter, lock the upper and lower dies, and make the supplemented position have a certain pressure. Note that the die cavity diameter is slightly smaller than the wire diameter by 0.1 ~ 0.2mm.
6. When the vulcanization time is up, take out the product. If a small amount of rubber overflows, repair it with a sharp blade and wipe it with diluent.

Causes and treatment of unqualified strand products

by

1. Scope of application
This specification is applicable to the stranding of copper aluminum strand, steel cored aluminum strand and power ABC Cable conductor core.
2. Equipment parameters
2.1 equipment name: jlk-500 / 12 + 18 + 24 frame stranding machine
2.2 equipment capacity (technical parameters)
a. Single wire diameter: 1.5 ~ 5mm (copper) 1.8 ~ 5mm (aluminum)
b. Maximum stranded outer diameter: 45 mm
c. Maximum traction speed: 69m / min
d. Maximum speed of frame: 12 discs R / min 173m
18 discs R / min 152 M
24 discs R / min 133 M
e. Equipment stranding pitch: 12 reels mm 56 ~ 962
18 disc mm 64 ～ 1095
24 disc mm 73 ~ 1245
f. Traction wheel diameter: φ 200 mm
g. Specification of pay off panel in frame: PND 500 mm
h. Specification of central pay off panel: pn800 ~ pn1600 mm
1. Specification of take-up reel: pn1250 ~ pn2500 mm
j. Main motor power kw: 75 (DC)


3. Preparation before production:
3.1 check whether all electromechanical equipment and transmission devices are normal, check the lubrication system, and apply pressure to the equipment according to the “oil standard”
Lubricating oil.
3.2 put the production tools and measuring tools (vernier caliper with accuracy of 0.02 mm and micrometer with accuracy of 0.01 mm) in a place convenient for use
A safe place and check whether the measuring tools are accurate.
3.3 according to the production plan, check whether the diameter of the single line is consistent with the process, and whether the single line is bruised, scratched, oxidized, etc,
Unqualified single line shall not be used.
3.4 prepare pressing wheel, die and other molds according to process requirements.
3.5 the take-up reel shall be selected according to the outer diameter, manufacturing length and process requirements of the strand, and the quality of the take-up reel shall be checked. The deformation is serious
Burrs on the edge of the side plate shall not be used.
3.6 the successor must understand the variety, specification and quality of twisted products and make clear the responsibility.
4. Key points of operation
4.1 before start-up, carefully check the correctness of operating parts, the reliability of interlocking mechanism and reel jacking, and the locking mechanism can make
The reel must be tightened and locked reliably, and the fence protection of the whole machine shall be set in place to ensure safety.
4.2 no matter under any circumstances, observe the changes of current, AAC Cables, temperature and other parameters at all parts at any time
In addition, any large fluctuation is dangerous and should be stopped immediately for inspection. Start up after troubleshooting.


4.3 according to the production plan and process requirements, the winding and branching shall be arranged according to the specified structure. When hanging the coil, pay attention to the balance and correct swing of the coil
The setting out direction of the reel shall be the same as that of the reel in a frame. The top clamp shall be screwed first and then locked and fixed with interlocking device,
Prevent accidents. Adjust the tension to achieve basic consistency.
4.4 the single line shall not be scratched or scratched when passing through the single line through the threading hole. The single line must be evenly separated through the threading hole or distribution board
Cross each other.
4.5 when installing the die, it must be aligned with the center, and check whether the die quality is good. The surface of the inner hole of the die or the pressing wheel and the conductor
The surface contact part shall be smooth, otherwise it shall not be put into use.
4.6 adjust the pitch and rotation direction of each section according to the process requirements.
4.7 lead wire: tightly wound outside the steel wire rope with a single wire to form a whole. Then start pulling and guiding from the die base of disc 12
Then 12 coils and 24 coils, gradually add stranded wires outside the core wire, and wind at least 4 turns on the traction wheel according to the branching slot.
Stop the machine when the conductor head is led to the reel. Replace the reel, remove the conductor head, and wrap the head tightly with tape and wire,
Prevent looseness. Insert the head into the threading hole on the disc core / side plate, extend the head for at least 1m, and use homogeneous wire to thread the coil
Wrap the brace for several turns and fix it firmly.
4.8 after the stranding machine is adjusted, the process inspection must be carried out comprehensively again, including the structure, direction, pitch
Start up after the outer diameter and number of strands fully meet the process requirements.
4.9 during the production of sector conductors, the sector height shall be adjusted at a slow speed and the pressure roller height shall be adjusted at the same time. Static pressure adjustment is not allowed
Roll to prevent breakage caused by uneven deformation of single line.
4.10 start up after process adjustment. After the strand reaches the traction wheel, actually measure the process parameters, such as pitch, outer diameter
The sector is high, and each process parameter shall be subject to the actual measurement, and each process parameter shall be filled in the self inspection form.
4.11 during the normal operation of the machine, the operator shall not leave the post without authorization, and it is found that the equipment is abnormal and the product quality is affected
In case of any problem, stop the vehicle for inspection in time.
4.12 when stopping, turn off the power supply and stop slowly. Emergency stop is allowed under special circumstances.
4.13 if the single line is allowed to have joints, the joints shall meet the requirements of the process card.
5. Precautions and treatment methods
5.1 always observe whether the electromechanical equipment and various instruments are in normal state.
5.2 regularly check whether the outer diameter (or fan height) pitch of the product is consistent with the process requirements, and fill in the self inspection form with the inspection results; If not, stop the vehicle for inspection and start the vehicle after handling.
5.3 pay attention to the surface quality and structural dimension of the line during the replacement of specifications, joints, adjustment plates and normal start-up.
5.4 the sector height of the compacted wire core must be controlled within the range specified in the process documents. If the requirements are not met, the pressure shall be adjusted in time
Wheel.
5.5 the take-up reel shall meet the requirements of users and products.
5.6 the wiring arrangement shall be tight and tidy, and no pressing, disorder, scratch and other phenomena are allowed. The finished product line shall be full if the user has special requirements
Meet user requirements. The distance between the outermost layer and the edge of tooling side plate shall not be less than 50mm
5.7 the length of the downlead shall meet the user’s requirements or the conductor wiring length requirements. After each reel is completed, the process shall be filled in
The product circulation card shall indicate the workshop, machine, model, specification, length, number of sections, shift, production date and product manufacturing information
Kuang et al.


6. After shift work:
6.1 cut off the main power supply after the work is completed.
6.2 report the equipment operation, product quality, problems, product specification and length of the shift to the successor in detail
The handover is clear.
6.3 keep the production process records of the shift, sort out the waste, clean the equipment, sort out the tools and measuring tools, clean the working place and clean the equipment
Do not use the mold temporarily and hand it over to the mold warehouse for storage.

Shielded vs unshielded cable, how to choose the answer here!

by

Shielded cable vs unshielded cable

Shielded cable? Or unshielded cable—— This is a problem. The choice of shielded or unshielded cables mainly depends on the specific application requirements. Today, Xiaobian sorted out the factors that should be considered when using shielded cables on AAC Cable treasure.
01
PART
Shielded cable
Shielded cable is a transmission line that uses metal mesh braid to wrap the signal line. The braid is generally red copper or tinned copper; Shielded cables are mainly used to prevent interference signals from entering the inner conductor and are suitable for transformers and similar equipment.
The shielded cable complies with the national standard: gb12972.6-91. The long-term allowable working temperature of the conductor is 90 ℃. It is suitable for the connecting wires of control and monitoring circuits and protection lines with rated voltage of 450 / 750V and below. It is mainly used in places where electromagnetic wave interference is prevented and shielding is required.
In order to minimize the impact of electromagnetic and radio frequency interference, each component in the shielding system must be seamless and correctly installed and maintained. In addition, shielded cables and systems also need good grounding. Incorrect grounding can cause radiation and interference problems in the system.

Single layer shielding

double-layer screen
Shielded stray wire
Single layer shielding
double-layer screen
Shielded cable assembly
02
PART
Unshielded cable
When wiring near EMI / RFI interference sources is not involved, unshielded ACSR Cables shall be selected in most cases. Unshielded cable has the advantages of light weight, high flexibility, wide use, reliability and low price. It is widely used in IT applications and office networks.

Unshielded dispersion
picture
Unshielded cable assembly
However, it should be noted that when enterprise networks or SMB networks want to achieve high data rates such as 10Gbps or 40Gbps on copper wires, the use of shielded cables can significantly reduce or even eliminate external crosstalk (AXT) harmful to network performance. This problem is mainly aimed at high-speed networks using category 6 cables, and does not involve low-speed 10 / 100 / 1000 networks using category 5 and category 6 cables.
It can be seen that the type of cable selected depends on the physical location of the network and the technology adopted (such as 10Base-T). The best practice is to thoroughly evaluate the installation location and network technical requirements, and then select the appropriate cable according to the specific specification requirements.

What are the effects of temperature on cable selection?

by

Whether our colleagues in electrical design or factory electrical maintenance can not open the topic of cable selection, we often see that the AAC Cable selection size of the same equipment under the same power will be different in the work, some may be less than one or two levels, and some friends may be confused by which right? Why do you choose different? Today we will learn how to choose the cable and how to consider it from? What is the effect of temperature on the selection of cables?


1、 Cable selection
(1) Select cable according to temperature rise
We all know that when the conductor passes through the load current, the temperature of the conductor will rise, the conductor has insulation layer, and the conductor temperature shall not exceed the maximum temperature allowed for a long time by the conductor insulation, and the conductor will be damaged after exceeding.
(2) According to mechanical strength
When laying, the conductor has a minimum section allowed according to the laying mode and the distance between the support point and the distance.
(3) Select according to economic conditions
That is, choose the most economical way.
(4) Select by line voltage drop
We all know that when the current passes through the conductor, the voltage drop will be generated in the line due to the existence of line impedance. If the voltage drop is too large, the voltage at the end of the line, that is, the load end is too low, which will cause the equipment to fail to work or affect the equipment life. Therefore, it is required that the voltage drop cannot be too large, so the cable section should be selected reasonably.

(5) Cable selection shall meet the requirements of load protection
When the circuit is in fault, the protective device should act according to the specified time, whether it can operate reliably or not has a great relationship with the cable section. Therefore, we should consider the requirements of reliable action when choosing the ACSR Cable.
(6) Select cable according to the requirements of thermal stability
In case of failure of cable or electrical equipment, the cable shall meet the requirements of thermal stability, and the size of cable section shall be considered in order to meet this requirement. The maximum cross section is the final result by combining the above conditions.