《电缆知识》PPT课件.ppt

Camesa 凯美莎 A WRCA Company 一个附属于美国钢丝绳公司的电缆公司 ACEROS CAMESA Manufactuting plant in Mexico City 制造厂位于墨西哥城 CAMESA, INC Sales and Distribution, Rosenberg, Texas 销售和发货地点位于得克萨斯，庐圣堡,Electromechanical Cable School 电缆电气和结构培训课程,History of EM Cables电缆的研发历史,1920s - First cables were large conductors tied together with friction tape. 19世纪20年代 -第一根缆绳是用绝缘胶布将一粗的导线捆在一起制成。 1940s First armored cable introduced with rubber insulation, 6- Conductor armored cable also introduced. 19世纪40年代 第一根铠装有橡胶绝缘材料的电缆投入市场，6芯铠装电缆也被投放到市场 1950s Fillers were used to reduce crosstalk, Improved compounds increased temperature rating to 350F. And the 7th Conductor was added. 19世纪50年代 填入线被用来减少串扰，改进了化合物的成分增加了温度等级到350度华氏并且增加了第七根缆芯。 1960s Development of smaller cables (5/16”, 7/32”) Teflon and Polypropylene was being used increasing the temperature rating to 450F. By the late 60s (3/16” and .202) cables were introduced for higher pressures. 19世纪60年代-开发了更细的电缆(5/16”，7/32”)使用了提高温度的聚四氟乙烯和聚丙烯温度达到华氏450度，在60年代后期(3/16”和0.202)的能耐更高压力的电缆被投放市场。,1970s Introduction of Tefzel for durability, and PFA Teflon for temperatures up to 550F, First alloy armor cable introduced for sour well work. 19世纪70年代- 太福隆的引入使得更为经久耐用并且PFA聚四氟乙烯的引入使得温度提高到华氏550度，第一根耐酸的油井合金铠装电缆面世。 1980s - Coax, water blocking, super seal being used. 19世纪80年代-花同轴电缆，水阻，超级密封技术被应用于电缆。 1990s Different corrosion resistant alloys being used to work at higher temperatures and chloride concentrations. 19世纪90年代-使用了不同的抗腐蚀合金材料以工作于更高的温度和氯化物的含量。 2000s Longer and stronger cables with Crush resistant cores and fiber optic cables. 20世纪初 -更长的和更坚硬的电缆与耐挤压的缆芯和光纤投入市场。,History of EM Cables电缆的研发历史,Topics for Discussion讨论话题,Properties of a Helix电缆的螺旋特性 Cable Design Factors电缆设计因素 Manufacturing Basics制造基础知识 Installation安装 Seasoning调整处理 Operations作业 Other Topics其它话题,Properties of a Helix 螺旋特性,With Tension 在张力作用下 The Helix will lengthen 电缆螺旋会伸长 Radial forces will compress the core 径向力会挤压缆芯 The cable will rotate 电缆会自我旋转,Properties of a Helix螺旋特性,With 2 Armors两层铠装结构 Rotation is in opposite directions内外铠旋转方向总是相反 Some of the torque is offsetting 造成某些扭矩被抵销,NORMALIZED CABLE 均衡电缆,A cable is in a normalized condition when the inner and outer armor layers are balanced and both of the armor layers are bearing an equal share of the load. 当内外铠装层扭矩平衡并且能够均衡承受负载时，我们就认为电缆是处于平衡状态。处于平衡状态的电缆称之为“均衡电缆”。,UN-NORMALIZED CABLE 不均衡的电缆,A cable is in an un-normalized condition when the inner and outer armor layers are not balanced and the inner armor is bearing a greater share of the load due to the loose condition of the outer armor. 当内外铠装层扭矩不均衡并且由于外铠松散，内铠承受较大负载时，我们就认为电缆是处于不均衡状态。,Un-normalized 不均衡,Causes of Un-Normalized Cable 导致电缆不均衡的原因,1. Failure to allow proper rotation of cable. 未能使电缆适当旋转. 2. Unequal tensions in and out of well. 上提与下放张力不一致. 3. Excessive speed in and out of well. 上提与下放速度过快 4. Improper use of pressure control equipment. 压力控制设备选择不当,10,000英尺,5,000 500 lbs,5000英尺 500磅,1000 lbs磅,Ideal Well理想的井况,Straight Hole 直井 No Sources of Friction 无摩擦源 Equal Wireline Tension In and Out of Hole 下放和上提时电缆张力均衡,上提,在非常完美的井况下的张力剖面,下井,深度英尺,下井相对于上提,在理想井况下的张力图,Real Well实际的井况,15,000,12,000,3000 lbs,8000 lbs,Pressure Control Equipment压力控制设备 Wellbore Fluid井眼流体 Deviation倾斜 Centralizers or Measurement Arms扶正器或测量推靠臂 Different Tensions In and Out Hole下放与上提时的张力不一致,实际井的张力剖面图,下井,上提,深度英尺,下井相对于上提,在实际井况下的张力图,High Strand 高较劲,Effects of Un-Normalized Cable 不均衡电缆造成的后果,1. Twisted and coiled cables at rig-up.安装时电缆打扭 2. Looseness of outer armor.外铠松散. 3. Bird caging.鸟笼现象. 4. Mud lumps under armor铠皮内积存有泥浆块 5. In extreme cases inner armor comes out of outer armor.严重时，内铠从外铠窜出 6. Inner armor or cable breaks at lower then rated breaking strength.内铠或电缆在标定抗拉值以下断裂 7. Excessive compression of core. 缆芯挤压严重.,Loose Armor外铠松散,Inner-break内铠断裂,Loosen 铠装松弛,Prevention of Un-Normalized Cable 预防电缆的不均衡,1. Equalize tension in and out of hole. Use 80/120 rule.下放与上提时保持张力一致 使用 80/120 原则 2. Run in and out of hole slowly enough that cable has time to rotate.下放与上提要足够慢，以便电缆有时间进行自行旋转 3. Whenever possible use a swivel between cable and tools.总是要在电缆和下井仪之间使用防转接头 4. Avoid packing off on moving cable.电缆运动时，封隔器离开电缆 5. Use proper size flow tubes.流管选择一定要合适. 6. Check cable for looseness and tighten when necessary. 经常检查电缆是否松散，必要时及时打紧再用,80/120 Rule 80/120规则,The tension going in should never be less then 80% of line weight plus tool weight. The tension coming out should never be more then 120% of line weight plus tool weight. 下放张力不应该是少于电缆悬重加上仪器重量的80%；上提张力不应该大于电缆悬重加上仪器重量的120%。,Usage and Design使用和设计,Cable Type Designation 电缆型号标识,示例,导线数量,铠装,内铠/外铠数量,名义上的直径，英寸/100,铜绞线型号,R、S-6根铜丝围绕一根中心铜丝,P-12根绕6根绕一根中心铜丝,T-18根绕12根绕6根绕一根中心铜丝,电绝缘材料型号,P-聚丙烯,T-氯化乙烯丙烯聚合物,Z-乙烯和四氟乙烯聚合物,A-泰氟龙,F-泰氟龙,Usage Design Requirements设计要求,Strength 强度 - High Strength 高强度 Electrical Power / Communication 电功率 / 通讯 - Low Resistance 低阻抗 Temperature Rating 温度范围 - 300/400/500/ F. Special designs 特殊设计 - Non-Corrosive Alloys 非-耐腐蚀合金 - S75 - S77 - MP35,Cable Design Improvements 电缆设计改进,Plastics 塑料 Super Seal超密封 High Temperature Tapes 高温绝缘带 Monofilament单丝 Water Blocking防水,Monofilament 单丝,Water Blocking防水,Pure Water and Pure Methane Gas can penetrate plastics纯净的水和纯净的甲烷气可能击穿塑料,Installation安装,Inspect Drum condition 检查滚筒状况 Entry hole and “dog knot” 滚筒的电缆入口和“尾结” Tension profile 张力剖面,Double Break Installation Method - Cable Breaks双跳缆安装法 跳缆,Winch Drum Surface 绞车滚筒表面,Upper Layer较高层,Lower Layer较低层,Spacer隔离物,Installation盘装,7J46 Spooling Profile 盘缆张力剖面,Tension张力 (lbs磅),Distance From Sliprings (kft)到滑环的距离（千英尺） Example for a 7J46 Cable， 7J46电缆的举例,Bed Layer底层,2nd Layer第二层,3rd Layer第3层,Min. Tension = 33% Breaking Strength 最低张力 = 拉断强度的33%,张力,Tension张力 (lbs磅),Distance From Sliprings (kft)到滑环的距离（千英尺） Example for a 1N32 Cable， 1N32电缆举例,Bed Layer底层,2nd Layer第2层,3rd Layer第3层,Min. Tension = 33% Breaking Strength 最低张力 = 拉断强度的33%,Normal Spooling Profile 正常的盘缆张力剖面,张力,Seasoning 整理处理,Seasoning整理,“Spin-out” 初次使用时，要在井中“破劲” Use a Test Well，Equal Tension in and out of hole. Use the 80/120 rule. 使用测试井下放与上提张力要尽量一致，使用80/120 法则. Flow Tubes and Packoff 流管和密封 New GIPS vs Alloy lines 新的注脂管对合金电缆,Well Configuration/ Preferably a test well Minimal Deviation Lighter Fluids Minimal Pressure 5000 井的结构/ 也许是一口测试井 最小偏离 较轻的井眼流体 最小压力 5000英尺,Proper Break In or Seasoning 破劲或整理,Tool Configuration to allow “Spin Out” Heavier Tools Swivels Nothing that will restrict rotation or tension Junk Basket / Centralizers, Decentralizers, Calipers, etc. 仪器结构，以也许自转 较重的仪器 防转接头 没有仪器将限制转动或拉紧 打捞蓝/扶正器、偏心器、井陉仪等等 .,Proper Break In or Seasoning 破劲或整理,Line Wiper Pressure刮缆压力 As minimal as possible, preferably “0” PSI尽可能最小，“0” PSI更好 Bigger flow tubes and used Line Wiper Rubbers较大的导流管和使用橡胶刮缆器 Speed Equal tension “In and Out”速度 下放、上提张力相等 Stop every 500 to allow for tool and cable rotation.每500英尺停一下并以使仪器和电缆自转 Stop every 2000 and pull up 100 to normalize cable.每2000英尺停一下并且上提100英尺以调制缆绳 Reduce speed to maintain Tension and allow rotation.降低速度维持张力和允许自转 Use 80/120 Rule采用80/120法则 New GIPS vs Alloy lines新的GIPS电缆相对于合金电缆,Proper Break In or Seasoning 破劲或整理,Line Speed While Seasoning 调制时的电缆速度,If the listed line speed exceeds the 80/120 rule, then follow the 80/120 rule.如果列出的电缆速度超出了80/120规则，则遵循80/120规则。,Line Speed for Seasoned Cables 调制过的电缆的电缆速度,67/133 Rule: Tension going into a well at any given depth should not be less then 67% of line weight 67/133规则：在任何给定深度时，下井的张力不得小于电缆重量的67%。 Tension coming out of the hole at any given depth should not exceed 133% of line weight plus tool weight including friction. 在任何给定深度下，上提张力 不应该超出电缆重量加仪器重量和阻力的133%。 Alloy cables never season and should always be run according to the 80/120 Rule. 合金电缆从不调制并且应该总是根据80/120法则运行。,Cable Crush电缆挤压,Uniform Plastic 均匀的塑料,Non-uniform Plastic 不均匀的塑料,Crushed Cable 挤压的电缆,Crushed Cable挤压的电缆,Cable Crush Area电缆挤压的部位,1. Crossover points. 交叉点 2. End of a layer, next to flange. 电缆靠近滚筒两侧法兰盘附近. 3. Crushing can also occur several layers below the maximum operating depth. 挤压可发生在最大测井深度时以下的几层中 4. Conductor damage due to cable crushing is not always immediately apparent. 由于挤压造成的缆芯损坏并不是立刻能够表现出来的,Preventing Cable Crush 防止电缆挤压,1. Install cables using recommended spooling profile. 严格按照推荐的盘装剖面安装电缆 2. Avoid slack in cable.避免电缆松弛 3. When stuck pull with steady tension, avoid jerking cable. 遇卡时，拉力要平稳、均匀，不可突然猛拉 4. When installation tension profile is changed due to job conditions, the cable should be respooled to reestablish the proper tension profile. 当由于工作条件（井眼状况）致使盘装张力剖面发生变化时，必须按照盘装张力剖面重新盘装,Preventing Cable Crush 防止电缆挤,Cable Drum- the distance between the flanges should not spread more than a cable diameter after installing the full cable length. 电缆滚筒- 在完全安装整根电缆后，电缆离开耳轮缘之间的距离不能大于电缆直径的。 The double break spooling pattern must be used . A single break installation puts substantially more crushing pressure on the core at the crossover points. 必须使用双跳缆安装法，单跳缆法在交叉点的缆芯上施加了极大的更多的挤压力。,Installation Tensions 安装张力,Preventing Cable Crush 预防电缆挤压,To maintain reasonable tension on the cable while going in the hole the speed must be regulated so that the cable tension does not drop below 2/3 of the static tension at that depth. 在缆绳上维持合理的张力，当下井时必须调控时速度，以便电缆张力不不至于下降到在那个深度时静态张力的2/3以下。 The cable speed coming out of the hole must be controlled so that the tension at any depth is not greater than 1-1/3 the static tension at that depth.上提电缆的速度一定要控制，以便在任何深度的张力不大于在那个深度的静态张力的1-1/3。,Preventing Cable Crush 预防电缆挤压,The cable should not be allowed to over run the bottom of the hole. If this happens the cable must be returned to the shop for re-spooling to establish the proper tension profile. 不应该允许过多的电缆下放到井底，如果发生，电缆必须返回到车间重新盘绕以建立适当的拉力剖面。 Using sheave wheels that are too small or improperly grooved can ruin a cable with one trip in the hole. 使用太小或不适当的滑轮樔的滑轮一次下井就能破坏电缆。,Preventing Cable Crush 预防电缆挤压,New cables must be treated carefully the first few trips in the hole. A new cable from the manufacture has been spooled on the shipping reel at very low tension. This new cable during the first trips in a hole will need to spin hundreds of revolutions to achieve torque balance. For this reason during these first trips the cable must be spooled very slowly in and out of the hole to allow the cable to normalize in torque. If done slowly, a new cable will become normalized in 4 to 5 trips. 新电缆最初的几次下井必须小心对待，一盘新电缆从工厂出来时以非常低的张力盘在运输滚筒上，这盘新电缆在第一次下井期间将需要转动数百圈以达到扭矩平衡，出于这个原因，在这些第一次下井期间电缆必须非常慢地下放、上提进出井眼以允许电缆扭矩正常化，如果慢慢地做，一盘新的电缆在4次到5次下井后将变得正常化。,Preventing Cable Crush 如何防止电缆挤压,1. Install cables using recommended spooling profile. 严格按照推荐的盘装剖面安装电缆 2. Avoid slack in cable.避免电缆松弛 3. When stuck pull with steady tension, avoid jerking cable. 遇卡时，拉力要平稳、均匀，不可突然猛拉 4. When installation tension profile is changed due to job conditions, the cable should be respooled to reestablish the proper tension profile. 当由于工作条件（井眼状况）致使盘装张力剖面发生变化时，必须按照盘装张力剖面重新盘装 5. Cable crushing is not a manufacturing defect and is not covered by our warranty 电缆挤压不是制造的缺陷并且它不属于我们索赔的范围,Crossed Armor Wire,铠装钢丝跳丝交叉,Crossed Armor Wire 铠装钢丝跳丝交叉,As a wireline cable tries to equalize the torque while descending into a well, crossed armors will move up the cable. The armor will move and may even pass through the flow tubes. Since this is a high armor (once moved), it will be scraped and will probably strand if not discovered. Another danger arises from armor wires being unevenly tensioned while building a rope socket. A small amount of slack in one or more armors may be “milked” back towards the winch where it could cause difficulty. 当下入井眼时，因为测井电缆设法调平扭矩，交叉铠装钢丝将向上移动缆绳，铠装钢丝将移动并且也许甚而穿过导流管，因为这是高出来的铠装钢丝(一旦被移动)，如果没有发现，它将被刮和可能交织在一起，另一危险是拉力参差不齐地的铠装钢丝出现钢丝绳套，在一根或更多铠装钢丝出现的小量的松驰也许被“挤奶似的”向后挤向滚筒，它可能造成麻烦，,In some cases, an armor wire has been “crossed“ on the flow tubes low-pressure side while the rope socket was built on the high-pressure side. With the low tension on the cable at this point, this “crossed“ wire can be chased for a considerable distance back up the cable before it causes a broken strandperhaps on a subsequent job. Crossed wires especially prevalent on alloy cables but can and do happen with GIPS cables 在某些情况下，当绳套形成于高压一侧时，一根铠装钢丝被交叉于导流管的低压一侧，在这一点电缆具有低的张力，这根“交叉的”钢丝可能被追逐到电缆的一个往后的可观的距离，在它导致断股之前 也许是在下一个随后的工作之前。交叉的钢丝在合金电缆中特别普遍，但在GIPS电缆中也能发生。,Crossed Armor Wire 铠装钢丝跳丝交叉,Crossed Wire跳丝交叉钢丝,Cable Operating procedures 电缆操作步骤,Correct Practice 正确的练习,It is well known that correct practices and experience can not only improve cable life, but also improve reliability. 人们都知道正确实践和经验可能不仅改进电缆寿命，而且改进可靠性。,Rig Up钻台安装,Ensure logging unit is correctly spotted.保证测井设备是正确地就位 Truck must be far enough from bottom sheave测井车到地滑轮有足够的距离 Drum flanges must line up with bottom sheave滚筒两侧法兰与地滑轮对准 Top sheave 天滑轮 Must line up with bottom sheave必须与地滑轮对准 Take care cable does not rub on derrick当心电缆不能与起吊转臂摩擦,Sheave Wheels滑轮,Sheave Wheel diameter 滑轮直径 3/16” Cable 12” Min. Dia. 7/32” cable 12” Min. Dia. 5/16” Cable 18” Min. Dia. 7/16” Cable 24” Min. Dia. 15/32” Cable 20” Min. Dia. Slammer加强电缆 (0.474”) 26” Min. Dia. 最小直径 Sheave dia. (calculation) 滑轮直径（计算） Min. diameter = approx 40 times cable dia 最小直径= 约40倍电缆直径 Min. diameter = approx 400 times largest armour wire dia. 最小直径=大约400倍于最大的铠装钢丝直径,Sheave Wheels滑轮,Groove too narrow Pinches cable 槽太窄小，夹电缆,Correct groove Cable well supported合适的槽宽，电缆被恰当地支撑,Groove too wide Cable squashed 槽太宽，电缆被挤压,Use correct sheave wheels 使用正确的滑轮,Sheave Groove滑轮槽,Sheave Groove滑轮槽,一新的滑轮的凹槽直径应该大于电缆直径5%。 滑轮凹槽直径不小于电缆直径10%，或者电缆则不应该用于这个滑轮。 滑轮凹槽与电缆接触点夹角为135到150度。滑轮不应该使用于2种不同直径的电缆。,Tension Operating Limits 张力操作极限,Rules of Thumb and Guidelines - apply to a normalized armor condition 适用于均衡化铠装情况的经验法则和操作指南,Rigging Equipment 井口安装设备 Tensions - In hole/Out hole张力 入井/出井 When using a seasoned cable, the 50/150 rule can apply 当使用一根调制过的电缆时，可应用 50/150规则 When the tension going in is 1/3 or less of the tension coming out, there is a lost of contact between the armor layers下井时的张力是上提的张力的1/3或少于，这样就减少了铠装层之间的摩擦 Temperature with Tension -Shock loading温度与张力-震动负载,Operations操作,Operations作业,Trouble shooting Electrically故障检索-电器的 Low Voltage / High Amps.= Short 低电压/高电流，= 短路 High Voltage / No Amps. = Open 高电压/无电流，= 断路 A partial short will be more difficult to locate 部分的短路将很难确定其位置 Splices 接电缆 Rig-up Line 钻台安装线 Trouble shooting Mechanically故障检索-机械的 Know what conditions the cable has undergone了解电缆经受了什么情况 The root cause of an electrical failure 电器故障的根本原因,Inspection and Maintenance,检查和维修,Inspection After Every Job 每次作业后检查,Visual inspection of rope sockets Electrical insulation/continuity testing Visual inspection for serious kinks along the rig-up length. Inspect cable for loose outer armor. Inspect splices for cracked shims and loose armor. Inspect cable for any abnormalities ( kinks, shiny spots, heavy pitting, crossed wires). Whenever reheading check for brittleness,用肉眼检查有无绳套,电绝缘/通断测试,沿井口安装的长度用肉眼检查有无严重纽结。,检查电缆外铠有无松动。,检查对接处薄膜合金片有无破裂和外壳有无松动。,检查电缆所有的反常现象(纽结，磨光的斑点、重度的锈斑，交叉的钢丝)。,每一次重做电缆头时检查脆性。,Inspection After Every Job 每次作业后检查,If abnormally high tensions were encountered while pulling out of the hole the cable should be pulled down and re installed with the proper tension profile. 当电缆被从井眼内上提时如果遭遇到反常地高张力，应该放下电缆并且采用以适当的张力剖面重新盘装。,Inspection for Brittleness 检查脆性,1. Take 8 armors from each layer (outer and inner). 从每层取8根铠装钢丝数(外层和内层)。 2. Wrap each armor wire around its own diameter for 5 complete wraps. 在它自己的直径周围绕5圈。 3. Unwrap the wire until it is straight. Good armor wire will not break when subjected to this test. If none of the armor wires breaks, the test is completed. Otherwise proceed to the next step. 松开钢丝，直到它变得平直，当遭受这个测试时，好的钢丝不会断裂，如果钢丝没有断裂，测试完成，否则进行下一个步骤。,4. If any wires from either layer breaks during the wrapping, the armor has lost too much ductility to be reliable. Cut off a portion of cable (500 ft to 1000 ft) and return to Step 1. 在撾圈期间，如果任一层任何一根钢丝断裂，钢丝肯定已经失去了许多延展性，切除部分电缆(500英尺到1000英尺)，并且回到第1步。,Inspection for Brittleness 检查脆性,Inspection for Brittleness 检查脆性,5. Wires breaking during the unwrapping would indicate some ductility has been lost. If 2 or more of the wires from either layer break during the unwrapping, scrap a portion of cable (500 ft to 1000 ft) and try again. If only 1 of the wires break, the cable probably has sufficient ductility for use, but is approaching the end of its service life and should be checked frequently. 在松开期间钢丝断裂表明一些延展性已经丢失，如果在松开期间从任何一层有2根或更多钢丝断裂，切除部分电缆(500英尺到1000英尺)并且再试一次，如果仅1根钢丝断裂，电缆或许还有充足的延展性可以使用，但已接近它的使用期限的结尾，并且应该频繁地检查。,6. You must use good judgment. If most of the wires in both layers break while unwrapping (instead of a few), you are close to a catastrophic failure; your safety factor is gone. At this point, cutting 500 ft or 1,000 ft and checking again is better than chancing a broken cable.您必须使用好的判断，当松开时，如果两层中有大多数(而不是一些)钢丝断裂，您将接近于一次灾难性的故障; 您的安全因素已经失去，这时，切掉500英尺或1,000英尺并且再检查比换掉这一残破的电缆要好。,Inspection for Brittleness 检查脆性,Inspection for Remaining Cable Life 检查电缆的残余寿命,Cables are lost or retired due to either mechanical damage, or to the normal wear and tear of field use. Mechanical damage includes: Bird-cages and kinks due to mishandling or loose armor. Crossed armor wires Drum Crush Insulation Damage 无论是由于机械损伤，或者由于野外使用的正常磨损，电缆无法恢复或退出使用。机械损伤包括： 由于处理不当或松动的铠装钢丝形成“鸟笼”和纽结。 交叉的铠装钢丝。 滚筒挤压。 盘装损坏。,Most cables are retired due to normal wear. Checks for normal wear should be done on a regular basis 多数电缆退出服务归结于正常磨损。 检查正常磨损应该经常定期完成。 Cut off 50 ft from the tool end of the cable and remove the armors from about two ft of cable. Separate the inner and outer armor wires into two piles. 从电缆接仪器的一端切除50英尺并且从电缆上剥开大约2英尺的铠装钢丝，分离内铠钢丝和外铠钢丝成二组。 Using a solvent, clean any dirt, mud, rust, or corrosion from the wires. 使用溶解剂，清洗钢丝上所有土、泥、铁锈或者铁锈。.,Inspection for Remaining Cable Life 检查电缆的残余寿命,Measure the diameter of the outer armor wire at the widest point then , measure at the narrowest point, do this for 8 wires. A 25 % or more loss of diameter is unacceptable. If there is more than 25 % reduction, cut off a portion of the cable and check further up. 然后在最粗的点测量外铠钢丝的直径，在最细的点测量，这样做8根钢丝，直径磨损25%或更多是不能接受的，如果有超过25%的减少，切除部分电缆并且进一步检查。 Perform a Brittleness test,