为保证电缆和电动机的正常工作，在选择电缆截面时，应遵守以下四条原则：（1）电缆正常运行时，其实际温升应不超过绝缘所允许的最高温升。（2）按电缆线路工作时的允许电压损失进行选择。（3）电缆截面的选择要满足机械强度的要求。
●电缆敷设时环境温度应不低于0℃。●电缆弯曲半径：三芯电缆不小于电缆外径15倍；单芯电缆不小于电缆外径20倍。电缆额定电压的选择●电缆的额定电压应适合于电缆系统的运行状况，用Uo/U（Um）KV表示。Uo--电缆设计用的导体对地或金属屏蔽之间的额定工频电压；U--电缆设计用的导体间的额定工频电压；Um--设备可承受的“最高系统电压”的最大值。
In manufacuring HYA communication cable, mine cable, mine communication cable, communication cable, mine cable, mine, mine control cable, cable for mine monitoring, mine monitoring cable, mine remote sensing cable, control cable, computer cable, flame retardant cable, fire-resistant cable,? Local communications cables, railway cables, communications equipment such as the power cord, communication cable in the city the main products are: manufacuring HYA, HYAT, HYAC, HYA22, HYA23, HYAT23, HYA53, HYAT53, ZRC - manufacuring HYA, ZRC - HYAT, WDZ - manufacuring HYA, ZRC - HYA23 series, such as product model complete specifications, has passed the holding center communication equipment network access license, constant standard logo certification, selling telecom company, has become many communication equipment supporting products, agreement is well received by customers and trust!
In flame retardant series products, has been successfully used in the oxygen isolation technology, not only 0.6/1 kv polyvinyl chloride insulated and crosslinked polyethylene insulation flame retardant power cable can achieve GB/T12666.5 "into A bunch of power cable test" in class A, and rated voltage up to and including 6/10 kv 6/10 kv crosslinked poly (flame retardant power cable can reach A high class A demand and A large margin. On the basis of high flame retardant and high flame retardant cross-linked insulation, a low-smoke halogen-free high-flame retardant oxygen insulation layer power cable was added, and its low-smoke halogen-free performance was in line with GB/T17651.1.2 and GB/ t1765650.1.2. In this way, the overall level of the company's cross-linked power cable is lower than the domestic status.
MHY32(PUYV39、PUYV39-1) 矿用聚乙烯绝缘阻燃聚氯乙烯护套单层钢丝铠装井筒信号电缆 用于斜井或竖井中作主信号电缆MHYVRP(PUYVRP) 矿用聚乙烯绝缘阻燃聚氯乙烯护套铜丝编织屏蔽信号软电缆用于井下平巷或斜巷作信号电缆MHYVP(PUYVP) 矿用聚乙烯绝缘阻。
PLC系统中使用的模拟量有两种，一种是模拟电压，一种是模拟电流，模拟电压最常见，用的也最多。模拟电压一般是0~10V，并联相等，长距离传输时容易受干扰，一般用在OEM设备中。模拟电流一般是4~20mA，串联相等，抗干扰能力强，dcs系统中一般都使用模拟电流。首先，我们先要用传感器测量我们所需要的参数，通过变送器将此参数变换成0~10V或者4~20mA，现在很多传感器都是自带变送器的，直接就输出模拟量，建议大家在项目中选用此种类型的传感器图二某压力传感器手册如图二所示，是某压力开关的选型手册，红色圆圈部分是它的量程0~250公斤，再看黄色荧光笔部分，此型号的传感器是模拟电流输出，也就是此款传感器将0~250公斤的压力线性转换成了4~20mA的电流，当我们检测到12mA的电流时，就表示压力是125公斤，依此类推。
如采用75－9同轴电缆时，摄像机和监视器间的距离在500m以内可不加电缆补偿器。HYA通信电缆，HYA22HYA23铠装通信电缆用途：实心绝缘填充型电缆适用于本地电信网的城市与乡镇电信线路，也适用于接入公用网的专用网线路。
/U：450/750V；3、最小弯曲半径：非铠装电缆不小于电缆外径的6倍；铠装电缆不小于电缆外径的12倍。在交联聚乙烯绝缘高阻燃的基础上又开发了低烟无卤高阻燃隔氧层电力电缆，其低烟无卤性能符合国家标准GB/T17651.1.2和GB/T17650.1.2。
XF5-273型旋卡式通信电缆交接箱|卡接式交接箱30对电话交接箱、50对电话交接箱、100对电话交接箱、150对电话交接箱、200对电话交接箱、300对电话交接箱、400对电话交接箱、500对电话交接箱 50对100对200对300对400对600对1200对2400对通信电缆交接箱HPVV5＊。
RVVZZRVVR铜芯聚乙烯绝缘软线。RS232/RS-485通讯电缆适用于EIARS-232/422通讯网络，是楼宇自控、工业控制网络、电力自动化等通讯网络的常用电缆型号。RS-485通讯电缆RS-485通讯电缆在一般场合采用双绞线就可以，但在要求比较高的环境下可以采用带屏蔽层的双绞电缆。
于是再次发起拒绝生产与使用含溴阻燃剂的行动。天津市电缆总厂第一分厂专业生产机场灯光线，机场灯光用电缆JDYJY-5KV1X6机场灯光用电缆DJ-JDKR-500V-1X2.51X4.机场灯的发展与飞机和航空事业的发展密切相关。
9.电线重量:1.5平方约重2.2公斤,2.5约重3.3公斤,4平方约重4.8公斤,6平方约重6.8公斤,快递以实际重量为准,只供参考.电线火线为红色，零线可选颜色有：红、黄、蓝、绿、棕、白、黑、双色几种。
可见，反馈系数具有电导（电阻的倒数）的量纲，称为互导反馈系数。,串联电压负反馈由3是同相比例运算电路。从反馈类型来看，反馈电路自输出端引出接到反相输人端，面后经电阻RL接“地”。设为正，则也为正.此时反相输入端的电位低于输出端的电位，但高于“地”电位，和的实际方向与电路中的参考方向相反。经RF和R1分压后.反馈电压=—R1它是的一部分。由输人端电路可得出，差值电压，即削弱了净输入电压(差值电压)，故为负反馈。
电缆端头必须使用防止水及其它腐蚀性材料的侵蚀，以防因水树引起绝缘层老化而导致击穿。电缆的装卸必须使用吊车或叉车，禁止平运，平放，大型电缆安装时须使用放缆车，以免电缆受外力损伤或因人工拖动而擦伤。电缆如因故不能及时敷设时，应将其放在干燥地方贮存，防止日光爆晒，电缆端头进水等。
Railway signal cable diameter, outside diameter product features: this product is suitable for rated voltage up to and ac 500 v or 1000 v dc transmission railway signals, audio signals or automatic device control circuit, including comprehensive sheathed, aluminum sheath railway signal cable has certain shielding performance, suitable for electrified sections or other areas that have high voltage interference installation. Use the cable features using the environment temperature of 40 ℃ ~ + 60 ℃. Cable conductor long-term working temperature shall not exceed + 70 ℃. Cable laying temperature: PVC sheathed cable should not below 0 ℃; Polyethylene outer sheath cable should be not less than 20 ℃. Allowable bending radius of cables: non-armoured cables shall not be less than 10 times of the outer diameter of cables; The armored cable shall not be less than 15 times the outer diameter of the cable. The ideal shielding coefficient of integrated sheathed railway signal cable is less than 0.8. The ideal shielding coefficient of aluminum sheath railway signal cable is less than 0.3
Propane burner plane with the flame of 750 ℃ and contact sample, sample in the compulsory blowing (5 m3 / min air emissions, wind speed 0.9 m/s), must be in vertical flame combustion is not up to 20 minutes, cable within 2.5 meters flame spread out on his own. IEC60332 is divided into A, B, C and D to evaluate the flame retardant performance.
MHJYV煤矿用加强型线芯聚乙烯绝缘聚氯乙烯护套通信电缆用于机械损伤较高的平巷和斜巷。HYA：铜芯实心聚烯烃绝缘挡潮层聚乙烯护套市内通信电缆。HYAT：铜芯实心聚烯烃绝缘填充式挡潮层聚乙烯护套市内通信电缆。