电工电气:弱电与强电基础知识及布线要求

日期:2019年11月07日 / 人气: / 来源:未知

强电


强电这一概念是相对于弱电而言,一般并无电压电流的具体界限划分。


人们习惯分为强电(电力)和弱电(信息)两部分。两者既有联系又有区别,一般来说强电的处理对象是能源(电力),其特点是电压高、电流大、功率大、频率低,主要考虑的问题是减少损耗、提高效率,弱电的处理对象主要是信息,即信息的传送和控制,其特点是电压低、电流小、功率小、频率高,主要考虑的是信息传送的效果问题,如信息传送的保真度、速度、广度、可靠性。一般来说,弱电工程包括电视工程、通信工程、消防工程、保安工程、影像工程等等和为上述工程服务的综合布线工程。弱电是针对强电而言的。强电=(380/220)、高压不管。



在电力系统中,36v以下的电压称为安全电压,3kv以下的电压称为低压,3kv以上的电压称为高压,直接供电给用户的线路称为配电线路,如用户电压为380/220v,则称为低压配电线路,也就是家庭装修中所说的强电(因它是家庭使用最高的电压)。强电一般是指交流电电压在24V以上。如家庭中的电灯、插座等,电压在110V~220V。家用电气中的照明灯具、电热水器、取暖器、冰箱、电视机、空调、音响设备等用电器均为强电电气设备。


智能化系统为建筑设备监控系统、安全防范系统、通讯网络系统、信息网络系统、火灾自动报警及消防联动等系统,以集中监视、控制和管理为目的构成的综合系统;家庭内各种数据采集、控制、管理及通讯的控制或网络系统等线路,则称为智能化线路(也就是家庭装修中所说的弱电)。弱电一般是指直流电路或音频、视频线路、网络线路、电话线路,直流电压一般在24V以内。家用电气中的电话、电脑、电视机的信号输入(有线电视线路)、音响设备(输出端线路)等用电器均为弱电电气设备。


弱电


弱电一般是指直流电路或音频、视频线路、网络线路、电话线路,直流电压一般在32V以内。家用电器中的电话、电脑、电视机的信号输入(有线电视线路)、音响设备(输出端线路)等用电器均为弱电电气设备。



建筑中的弱电主要有两类:一类是国家规定的安全电压等级及控制弱电电压等低电压电能,有交流与直流之分,如24V直流控制电源,或应急照明灯备用电源。另一类是载有语音、图像、数据等信息的信息源,如电话、电视、计算机的信息。


狭义上的建筑弱电主要是指:安防(监控、周界报警、停车场)、消防(电气部分)、楼控以及网络综合布线和音频系统等。


强电和弱电从概念上讲,一般是容易区别的,主要区别是用途的不同。强电是用作一种动力能源,弱电是用于信息传递。它们大致有如下区别:


1


交流频率不同


强电的频率一般是50Hz(赫),称“工频”,意即工业用电的频率:弱电的频率往往是高频或特高频,以KHz(千赫)、MHz(兆赫)计。


2


传输方式不同


强电以输电线路传输,弱电的传输有有线与无线之分。无线电则以电磁波传输。


3


功率、电压及电流大小不同


强电一般电压在36V以上,弱电电压一般低于36V。


4


分类


建筑中的弱电主要有两类:一类是国家规定的安全电压等级及控制电压等低电压电能,有交流与直流之分,如24V直流控制电源,或应急照明灯备用电源。另一类是载有语音、图像、数据等信息的信息源,如电话、电视、计算机的信息。


功能及应用


电力应用按照电力输送功率的强弱可以分为强电与弱电两类。建筑及建筑群用电一般指交流220V50Hz及以上的强电。主要向人们提供电力能源,将电能转换为其他能源,例如空调用电,照明用电,动力用电等等。


智能建筑中的弱电主要有两类,一类是国家规定的安全电压等级及控制电压等低电压电能,有交流与直流之分,交流36V以下,直流24V以下,如24V直流控制电源,或应急照明灯备用电源。另一类是载有语音、图像、数据等信息的信息源,如电话、电视、计算机的信息。


人们习惯把弱电方面的技术称之为弱电技术。可见智能建筑弱电技术基本涵义仍然是原来意义上的弱电技术。只不过随着现代弱电高新技术的迅速发展,智能建筑中的弱电技术应用越来越广泛。 一般情况下,弱电系统工程指第二类应用。


主要包括:1、电视信号工程,如电视监控系统,有线电视。2、通信工程,如电话。3、智能消防工程。4、扩声与音响工程,如小区的中背景音乐广播,建筑物中的背景音乐。5、综合布线工程,主要用于计算机网络。随着计算机技术的飞速发展,软硬件功能的迅速强大,各种弱电系统工程和计算机技术的完美结合,使以往的各种分类不再像以前那么清晰。各类工程的相互融合,就是系统集成。


常见的弱电系统工作电压包括:24VAC、16.5VAC、12VDC,有的时候220VAC也算弱电系统,比如有的由摄像机的工作电压是220VAC,我们就不能把它们归入强电系统。弱电系统主要针对的是建筑物,包括大厦、小区、机场、码头、铁路、高速公路等。


常见的弱电系统包括:闭路电视监控系统、防盗报警系统、门禁系统、电子巡更系统、停车场管理系统、可视对讲系统、家庭智能化系统及安防系统、背景音乐系统、LED显示系统、等离子拼接屏系统、DLP大屏系统、三表抄送系统、楼宇自控系统、防雷与接地系统、寻呼对讲及专业对讲系统、弱电管道系统、UPS不间断电源系统、机房系统、综合布线系统、计算机局域网系统、物业管理系统、多功能会议室系统、有线电视系统、卫星电视系统、卫星通讯系统、消防系统、电话通讯系统、酒店管理系统、视频点播系统、人力资源管理系统等等。


强电与弱电为什么分开


区分强弱电是因为强弱电之间能不能共槽,否则会干扰弱电的信息传输,影响家中电视、电脑、电话的使用,甚至还可能造成火灾。


那么,在强弱电施工中,如何避免弱电被干扰,以及线路布置中具体有哪些注意事项呢,主要有以下5点:


1


强弱电要分开


在装修中,电路布线改造最忌讳的事情,是把所有线路收纳到一起。所以在改造电路施工时,国家标准是:强弱电要分开走线,禁止共管共盒,且强弱电之间线路的平行距不得小于30cm。但是考虑到实际情况(现代公寓没有做到30cm以上的条件),讲究一些的装修公司会至少留出15厘米,保证留出距离。这个距离也能保证不会出现强电干扰弱电的情况。



2


不同弱电线也要分开


不同的弱电线在一起也会造成信号干扰,为避免这种情况,像电话线、网线、电视线等弱电线在线路作业时一定要分开穿管,不可共用同一条管。


3


布线在前走线在后


无论是强电还是弱电,在布线施工时,应遵循先安装管路再穿线的规则,这样做是为了防止出现无法抽动的现象,方便以后进行维护换线。


4


同一管内线路不宜过多


在强弱电线路布设时,所需管数应当根据导线数量而变化,原则上一根管子不能超过四根导线,千万不能有导线把管内空间塞满的情况。像一般弯管的利用率在四成到五成之间,直线管可以稍高一些,在五成到六成之间为宜。


5


忌避免折断式直角弯


在施工走线中,遇到线路需转弯的情况,千万不能出现折断式的转直角,这样很可能会影响信号强度,且造成导线无法穿过的情况,因此,最好采用大弯,金属角来过弯连接导线。

High voltage




The concept of strong current is that compared with weak current, there is generally no specific limit of voltage and current.




People's habits are divided into strong electricity (electricity) and weak electricity (information). , there are both connection and difference in general heavy current processing object is energy (electricity), its characteristic is high voltage, large current, large power, low frequency, the main concern is to reduce loss, improve efficiency, the processing of weak current object mainly is information, the information transmission and control, its characteristic is low voltage, small current, power, high frequency and the main consideration is the effect of information transmission problems, such as fidelity of information transmission, speed, breadth, and reliability. Generally speaking, the weak current project includes the television project, the communication project, the fire protection project, the security project, the image project and so on and serves for the above project the synthesis wiring project. Weak electricity is for strong electricity. Strong electric =(380/220), high voltage regardless.






In power system, 36 v called safe voltage, under voltage 3 kv voltages below, 3 kv voltage as high pressure, the line is called distribution circuit of the power supply to the user directly, such as user voltage of 380/220 v, is known as the low voltage power distribution line, is the family is decorated in the high voltage (because it is the highest voltage in the family use). Strong current generally means alternating current voltage in 24V above. Such as the electric light in the family, socket, voltage in 110V~220V. Domestic electric lighting lamps, electric water heater, heater, refrigerator, television, air conditioning, audio equipment and other electrical appliances are strong electric equipment.




The intelligent system consists of building equipment monitoring system, safety prevention system, communication network system, information network system, automatic fire alarm and fire linkage system, etc. It is an integrated system with the purpose of centralized monitoring, control and management. All sorts of data collect inside the home, control, management and communication control or the line such as network system, call intelligent line (namely the weak current that the family decorates in saying). Weak current is to point to direct current circuit commonly or audio, video line, network line, telephone line, dc voltage is in 24V commonly less than. The signal input of telephone, computer and TV set in household electrical appliances (cable TV line), audio equipment (output line) and other electrical appliances are weak current electrical equipment.




Weak current




Weak current is to point to direct current circuit commonly or audio, video line, network line, telephone line, direct current voltage is in commonly 32V less than. The signal input of telephone, computer and TV in household appliances (cable TV line), audio equipment (output line) and other electrical appliances are weak current electrical equipment.






There are mainly two types of weak current in buildings: one is the safety voltage level stipulated by the state and the control of weak voltage and other low-voltage electric energy, which can be divided into ac and dc, such as 24V dc control power supply, or emergency lighting backup power supply. Another is the information source that contains information such as voice, image, data, etc., such as telephone, television, computer information.




The building weak current on narrow sense basically is to point to: security prevent (monitor, perimeter alarm, parking lot), fire protection (electrical part), floor control and network are integrated wiring and audio system.




Strong electricity and weak electricity from the concept, generally easy to distinguish, the main difference is the use of different. Strong electricity is used as a power source, weak electricity is used for information transmission. They differ roughly as follows:




1




Different ac frequency




The frequency of strong electricity is generally 50Hz(Hertz), called "power frequency", which means the frequency of industrial electricity: the frequency of weak electricity is often high frequency or ultra-high frequency, in KHz(KHz), MHz(MHz) meter.




2




Different transmission mode




Strong power is transmitted by transmission line, weak power transmission can be divided into wired and wireless. Radio transmits in electromagnetic waves.




3




Power, voltage and current are different




Strong voltage is generally more than 36V, weak voltage is generally less than 36V.




4




classification




There are mainly two types of weak electricity in buildings: one is the state specified safety voltage level and control voltage and other low voltage electric energy, there are ac and dc points, such as 24V dc control power supply, or emergency lighting backup power supply. Another is the information source that contains information such as voice, image, data, etc., such as telephone, television, computer information.




Functions and applications




Electric power application can be divided into strong and weak electric power according to the strength of electric power transmission. Building and building complex electricity generally refers to ac 220V50Hz and above strong electricity. It mainly provides people with electric energy, which can be converted into other energy, such as air conditioning electricity, lighting electricity, power electricity and so on.




There are mainly two types of weak electricity in intelligent buildings, one is the safety voltage level and control voltage and other low voltage electric energy stipulated by the state, which can be divided into ac and dc, ac under 36V, dc under 24V, such as 24V dc control power supply, or emergency lighting backup power supply. Another is the information source that contains information such as voice, image, data, etc., such as telephone, television, computer information.




People are used to calling weak current technology weak current technology. It can be seen that the basic meaning of weak current technology of intelligent building is still weak current technology in the original sense. However, with the rapid development of modern weak current technology, the application of weak current technology in intelligent buildings is more and more extensive. Generally, weak current system engineering refers to the second class of applications.




Main include: 1, television signal engineering, such as television monitoring system, cable television. 2. Communication engineering, such as telephone. 3. Intelligent fire protection engineering. 4. Sound reinforcement and sound engineering, such as music broadcasting in the middle background of the community and music broadcasting in the background of the building. 5, integrated wiring project, mainly used for computer network. With the rapid development of computer technology, the software and hardware functions of the rapid and powerful, a variety of weak current system engineering and computer technology perfect combination, so that the previous classification is no longer as clear as before. The mutual integration of various projects is system integration.




Common weak current system working voltage includes: 24VAC, 16.5vac, 12VDC, sometimes 220VAC is also weak current system, for example, some by the camera working voltage is 220VAC, we can not put them into the strong current system. Weak current system is mainly aimed at buildings, including buildings, communities, airports, docks, railways, highways and so on.




Common weak current systems include: Closed-circuit television monitoring system, anti-theft alarm system, entrance guard system, electronic patrol system, parking management system, visual intercom, home intelligent system and security system, background music system, LED display system, plasma splicing screen area, DLP systems, systems, building automation systems, lightning protection and grounding system, paging intercom and professional intercom, weak current pipeline system, UPS uninterruptible power supply system, computer system, integrated wiring system, computer local area network (LAN) system, property management system, multi-functional conference room system, cable television system, satellite television system, satellite communication system, fire fighting System, telephone communication system, hotel management system, video vod system, human resource management system and so on.




Why are strong and weak currents separated




Distinguish between strong and weak electricity is because between strong and weak electricity can total slot, otherwise will interfere with the weak electricity information transmission, affect the use of TV, computer, telephone in the home, even may cause a fire.




Then, in the construction of strong and weak electricity, how to avoid the interference of weak electricity, and the specific points for attention in the line layout, mainly include the following five points:




1




Strong and weak electricity should be separated




In decorating, circuit wiring changes the most taboo thing, it is to receive all lines together. So in the construction of the transformation circuit, the national standard is: strong and weak electricity to separate wire, prohibit condominium total box, and the parallel distance between the strong and weak electricity line must not be less than 30cm. But consider actual situation (contemporary apartment did not accomplish the condition of 30cm above), exquisite a few decorate a company to be able to put apart 15 centimeters at least, assure put apart distance. This distance also ensures that strong current will not interfere with weak current.






2




Separate the weak wires




Different weak wire also can cause signal interference together, in order to avoid this kind of circumstance, the weak wire such as telephone line, network line, TV line must be worn separately when line operation, cannot share same tube.




3




Wiring in front and wiring in back




No matter be strong current or weak current, when wiring construction, should follow the rule that installs conduit to traverse again first, do so is to prevent to appear the phenomenon that cannot twitch, undertake maintenance to change a line conveniently later.




4




The same pipe line should not be too much




In the strong and weak electric circuit layout, the number of required tubes should be based on the number of conductors and change, in principle, a tube can not exceed four wires, must not have a wire to fill up the space inside the tube. The utilization rate that resembles general bend tube is between 40 and 50, linear tube can a few taller, it is advisable to be between 50 and 60.




5




Avoid breaking right Angle bend




In construction go through a line, encounter the circumstance that line needs turn, must not appear broken type turn right Angle, such likelihood can affect signal intensity, and cause the case that the wire cannot pass through, accordingly, had better use big bend, metal horn will pass the case that joins a wire.


作者:佚名


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