一、屏蔽線是什么
屏蔽(bi)線(xian)是(shi)使(shi)用網(wang)狀編織導(dao)線(xian)把信(xin)號(hao)線(xian)包(bao)裹(guo)起(qi)來的傳(chuan)輸線(xian)。導(dao)線(xian)外部(bu)有導(dao)體包(bao)裹(guo)的導(dao)線(xian)叫屏蔽(bi)線(xian),包(bao)裹(guo)的導(dao)體叫屏蔽(bi)層(ceng),一般為(wei)編織銅網(wang)或(鋁),屏蔽(bi)層(ceng)需要接(jie)地(di),外來的干(gan)擾(rao)信(xin)號(hao)可被(bei)該層(ceng)導(dao)入(ru)大(da)地(di),避免干(gan)擾(rao)信(xin)號(hao)進入(ru)內層(ceng)導(dao)體干(gan)攏同時降低傳(chuan)輸信(xin)號(hao)的損耗。
屏(ping)蔽電(dian)纜(lan)的(de)(de)(de)屏(ping)蔽層主(zhu)要由銅(tong)、鋁等非磁性材料制成,并(bing)且(qie)厚(hou)度(du)(du)很(hen)薄,遠(yuan)小(xiao)于使用頻(pin)率(lv)上金屬材料的(de)(de)(de)集膚深(shen)度(du)(du)(所謂趨(qu)膚效應(ying)是(shi)指電(dian)流(liu)在導(dao)體(ti)截(jie)面的(de)(de)(de)分(fen)(fen)布隨(sui)頻(pin)率(lv)的(de)(de)(de)升高(gao)而趨(qu)于導(dao)體(ti)表面分(fen)(fen)布,頻(pin)率(lv)越(yue)(yue)(yue)高(gao),趨(qu)膚深(shen)度(du)(du)越(yue)(yue)(yue)小(xiao),即頻(pin)率(lv)越(yue)(yue)(yue)高(gao),電(dian)磁波的(de)(de)(de)穿透能力越(yue)(yue)(yue)弱),屏(ping)蔽層的(de)(de)(de)效果(guo)主(zhu)要不是(shi)由于金屬體(ti)本(ben)身對電(dian)場、磁場的(de)(de)(de)反射、吸收而產生(sheng)的(de)(de)(de),而是(shi)由于屏(ping)蔽層的(de)(de)(de)接地產生(sheng)的(de)(de)(de),接地的(de)(de)(de)形式不同將直接影響(xiang)屏(ping)蔽效果(guo)。
二、屏蔽線分類
主要包括裸線、電磁線及電機電器用絕緣電線、電力電纜、通信電纜與光纜。電線電纜是指用于電力、通信及相關傳輸用途的材料。“電線”和“電纜”并沒有嚴格的界限。通常將芯數少、產品直徑小、結構簡單的產品稱為電線,沒有絕緣的稱為裸電線,其他的稱為電纜;導體截面積較大的(大于6平(ping)方毫米)稱為大電線,較小的(小于或等(deng)于6平方(fang)毫米(mi))稱為小電(dian)(dian)(dian)(dian)線(xian)(xian),絕緣電(dian)(dian)(dian)(dian)線(xian)(xian)又稱為布電(dian)(dian)(dian)(dian)線(xian)(xian)。電(dian)(dian)(dian)(dian)線(xian)(xian)電(dian)(dian)(dian)(dian)纜(lan)主要包括裸(luo)線(xian)(xian)、電(dian)(dian)(dian)(dian)磁線(xian)(xian)及電(dian)(dian)(dian)(dian)機電(dian)(dian)(dian)(dian)器(qi)用絕緣電(dian)(dian)(dian)(dian)線(xian)(xian)、電(dian)(dian)(dian)(dian)力電(dian)(dian)(dian)(dian)纜(lan)、通信電(dian)(dian)(dian)(dian)纜(lan)與光(guang)纜(lan)。電(dian)(dian)(dian)(dian)纜(lan)有電(dian)(dian)(dian)(dian)力電(dian)(dian)(dian)(dian)纜(lan)、控制電(dian)(dian)(dian)(dian)纜(lan)、補償電(dian)(dian)(dian)(dian)纜(lan)、屏蔽電(dian)(dian)(dian)(dian)纜(lan)、高溫(wen)電(dian)(dian)(dian)(dian)纜(lan)、計算機電(dian)(dian)(dian)(dian)纜(lan)、信號(hao)電(dian)(dian)(dian)(dian)纜(lan)、同軸電(dian)(dian)(dian)(dian)纜(lan)、耐火(huo)電(dian)(dian)(dian)(dian)纜(lan)、船(chuan)用電(dian)(dian)(dian)(dian)纜(lan)等等。它們(men)都是由多股(gu)導(dao)線(xian)(xian)組成,用來連接電(dian)(dian)(dian)(dian)路、電(dian)(dian)(dian)(dian)器(qi)等。
普(pu)通(tong):絕緣層+屏蔽層+導(dao)線。高(gao)級:絕緣層+屏蔽層+信號(hao)導線(xian)+屏蔽層接地導線(xian)。
三、屏蔽線型號
AVSSBS是(shi)日系的單芯、AVSSBS2*是雙芯、N901 906。02是德(de)系的(de)三芯(xin)。
四、屏蔽線的作用
屏蔽層(ceng)一般需要接地。屏蔽線的作用是(shi)將(jiang)電磁場(chang)噪(zao)聲(sheng)源與敏感設備隔離,切斷噪(zao)聲(sheng)源的傳(chuan)播(bo)路(lu)徑。
屏蔽(bi)分(fen)為主動(dong)(dong)屏蔽(bi)和(he)被動(dong)(dong)屏蔽(bi),主動(dong)(dong)屏蔽(bi)目的(de)是(shi)(shi)(shi)為了(le)(le)防止(zhi)噪(zao)聲(sheng)源向外輻(fu)射,是(shi)(shi)(shi)對(dui)噪(zao)聲(sheng)源的(de)屏蔽(bi);被動(dong)(dong)屏蔽(bi)目的(de)是(shi)(shi)(shi)為了(le)(le)防止(zhi)敏感(gan)設備遭到(dao)噪(zao)聲(sheng)源的(de)干(gan)擾,是(shi)(shi)(shi)對(dui)敏感(gan)設備的(de)屏蔽(bi)。
屏(ping)蔽(bi)(bi)線的(de)屏(ping)蔽(bi)(bi)層不允許(xu)多點接(jie)地(di),因(yin)為不同的(de)接(jie)地(di)點總是不一樣的(de),各點存在電位差。如多點接(jie)地(di),在屏(ping)蔽(bi)(bi)層形成電流(liu),感應到導線上形成電流(liu),感應到信號線上形成干擾(rao)(rao),不但起不到屏(ping)蔽(bi)(bi)作用(yong),反而引進干擾(rao)(rao),尤其在變頻器(qi)用(yong)的(de)多的(de)場合里,干擾(rao)(rao)中含有各種高(gao)次諧波分量,造成影響更(geng)大,應特別注(zhu)意。