• 電工電氣:弱電與強電基礎知識及布線要求

    日期:2019年11月07日 / 人氣: / 來源:未知

    強電


    強電這一概念是相對于弱電而言,一般并無電壓電流的具體界限劃分。


    人們習慣分為強電(電力)和弱電(信息)兩部分。兩者既有聯系又有區別,一般來說強電的處理對象是能源(電力),其特點是電壓高、電流大、功率大、頻率低,主要考慮的問題是減少損耗、提高效率,弱電的處理對象主要是信息,即信息的傳送和控制,其特點是電壓低、電流小、功率小、頻率高,主要考慮的是信息傳送的效果問題,如信息傳送的保真度、速度、廣度、可靠性。一般來說,弱電工程包括電視工程、通信工程、消防工程、保安工程、影像工程等等和為上述工程服務的綜合布線工程。弱電是針對強電而言的。強電=(380/220)、高壓不管。



    在電力系統中,36v以下的電壓稱為安全電壓,3kv以下的電壓稱為低壓,3kv以上的電壓稱為高壓,直接供電給用戶的線路稱為配電線路,如用戶電壓為380/220v,則稱為低壓配電線路,也就是家庭裝修中所說的強電(因它是家庭使用最高的電壓)。強電一般是指交流電電壓在24V以上。如家庭中的電燈、插座等,電壓在110V~220V。家用電氣中的照明燈具、電熱水器、取暖器、冰箱、電視機、空調、音響設備等用電器均為強電電氣設備。


    智能化系統為建筑設備監控系統、安全防范系統、通訊網絡系統、信息網絡系統、火災自動報警及消防聯動等系統,以集中監視、控制和管理為目的構成的綜合系統;家庭內各種數據采集、控制、管理及通訊的控制或網絡系統等線路,則稱為智能化線路(也就是家庭裝修中所說的弱電)。弱電一般是指直流電路或音頻、視頻線路、網絡線路、電話線路,直流電壓一般在24V以內。家用電氣中的電話、電腦、電視機的信號輸入(有線電視線路)、音響設備(輸出端線路)等用電器均為弱電電氣設備。


    弱電


    弱電一般是指直流電路或音頻、視頻線路、網絡線路、電話線路,直流電壓一般在32V以內。家用電器中的電話、電腦、電視機的信號輸入(有線電視線路)、音響設備(輸出端線路)等用電器均為弱電電氣設備。



    建筑中的弱電主要有兩類:一類是國家規定的安全電壓等級及控制弱電電壓等低電壓電能,有交流與直流之分,如24V直流控制電源,或應急照明燈備用電源。另一類是載有語音、圖像、數據等信息的信息源,如電話、電視、計算機的信息。


    狹義上的建筑弱電主要是指:安防(監控、周界報警、停車場)、消防(電氣部分)、樓控以及網絡綜合布線和音頻系統等。


    強電和弱電從概念上講,一般是容易區別的,主要區別是用途的不同。強電是用作一種動力能源,弱電是用于信息傳遞。它們大致有如下區別:


    1


    交流頻率不同


    強電的頻率一般是50Hz(赫),稱“工頻”,意即工業用電的頻率:弱電的頻率往往是高頻或特高頻,以KHz(千赫)、MHz(兆赫)計。


    2


    傳輸方式不同


    強電以輸電線路傳輸,弱電的傳輸有有線與無線之分。無線電則以電磁波傳輸。


    3


    功率、電壓及電流大小不同


    強電一般電壓在36V以上,弱電電壓一般低于36V。


    4


    分類


    建筑中的弱電主要有兩類:一類是國家規定的安全電壓等級及控制電壓等低電壓電能,有交流與直流之分,如24V直流控制電源,或應急照明燈備用電源。另一類是載有語音、圖像、數據等信息的信息源,如電話、電視、計算機的信息。


    功能及應用


    電力應用按照電力輸送功率的強弱可以分為強電與弱電兩類。建筑及建筑群用電一般指交流220V50Hz及以上的強電。主要向人們提供電力能源,將電能轉換為其他能源,例如空調用電,照明用電,動力用電等等。


    智能建筑中的弱電主要有兩類,一類是國家規定的安全電壓等級及控制電壓等低電壓電能,有交流與直流之分,交流36V以下,直流24V以下,如24V直流控制電源,或應急照明燈備用電源。另一類是載有語音、圖像、數據等信息的信息源,如電話、電視、計算機的信息。


    人們習慣把弱電方面的技術稱之為弱電技術??梢娭悄芙ㄖ蹼娂夹g基本涵義仍然是原來意義上的弱電技術。只不過隨著現代弱電高新技術的迅速發展,智能建筑中的弱電技術應用越來越廣泛。 一般情況下,弱電系統工程指第二類應用。


    主要包括:1、電視信號工程,如電視監控系統,有線電視。2、通信工程,如電話。3、智能消防工程。4、擴聲與音響工程,如小區的中背景音樂廣播,建筑物中的背景音樂。5、綜合布線工程,主要用于計算機網絡。隨著計算機技術的飛速發展,軟硬件功能的迅速強大,各種弱電系統工程和計算機技術的完美結合,使以往的各種分類不再像以前那么清晰。各類工程的相互融合,就是系統集成。


    常見的弱電系統工作電壓包括:24VAC、16.5VAC、12VDC,有的時候220VAC也算弱電系統,比如有的由攝像機的工作電壓是220VAC,我們就不能把它們歸入強電系統。弱電系統主要針對的是建筑物,包括大廈、小區、機場、碼頭、鐵路、高速公路等。


    常見的弱電系統包括:閉路電視監控系統、防盜報警系統、門禁系統、電子巡更系統、停車場管理系統、可視對講系統、家庭智能化系統及安防系統、背景音樂系統、LED顯示系統、等離子拼接屏系統、DLP大屏系統、三表抄送系統、樓宇自控系統、防雷與接地系統、尋呼對講及專業對講系統、弱電管道系統、UPS不間斷電源系統、機房系統、綜合布線系統、計算機局域網系統、物業管理系統、多功能會議室系統、有線電視系統、衛星電視系統、衛星通訊系統、消防系統、電話通訊系統、酒店管理系統、視頻點播系統、人力資源管理系統等等。


    強電與弱電為什么分開


    區分強弱電是因為強弱電之間能不能共槽,否則會干擾弱電的信息傳輸,影響家中電視、電腦、電話的使用,甚至還可能造成火災。


    那么,在強弱電施工中,如何避免弱電被干擾,以及線路布置中具體有哪些注意事項呢,主要有以下5點:


    1


    強弱電要分開


    在裝修中,電路布線改造最忌諱的事情,是把所有線路收納到一起。所以在改造電路施工時,國家標準是:強弱電要分開走線,禁止共管共盒,且強弱電之間線路的平行距不得小于30cm。但是考慮到實際情況(現代公寓沒有做到30cm以上的條件),講究一些的裝修公司會至少留出15厘米,保證留出距離。這個距離也能保證不會出現強電干擾弱電的情況。



    2


    不同弱電線也要分開


    不同的弱電線在一起也會造成信號干擾,為避免這種情況,像電話線、網線、電視線等弱電線在線路作業時一定要分開穿管,不可共用同一條管。


    3


    布線在前走線在后


    無論是強電還是弱電,在布線施工時,應遵循先安裝管路再穿線的規則,這樣做是為了防止出現無法抽動的現象,方便以后進行維護換線。


    4


    同一管內線路不宜過多


    在強弱電線路布設時,所需管數應當根據導線數量而變化,原則上一根管子不能超過四根導線,千萬不能有導線把管內空間塞滿的情況。像一般彎管的利用率在四成到五成之間,直線管可以稍高一些,在五成到六成之間為宜。


    5


    忌避免折斷式直角彎


    在施工走線中,遇到線路需轉彎的情況,千萬不能出現折斷式的轉直角,這樣很可能會影響信號強度,且造成導線無法穿過的情況,因此,最好采用大彎,金屬角來過彎連接導線。

    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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