熔斷管中石英砂填料的作用低壓石板閘配用的熔斷管，膠木內部多以石英砂做填充物，目的是電弧在石英砂中燃燒，熔件蒸發形成熾熱空氣滲入填料中迅速凝結，增加滅弧效果。填料在熔管中極為重要，更換熔件時必須注意：

    1.填料要如數裝進熔管，不(bu)能撒棄(qi)少裝或不(bu)裝；

    2.在野外更(geng)換熔件時，填料(liao)中不可混合泥(ni)土和(he)雜草；

    3.兩側的螺旋帽蓋必(bi)須擰緊、不可使填料(liao)泄漏。

    低壓熔斷器的種(zhong)類和技術特性：

    有(you)填料熔(rong)斷器有(you)填料熔(rong)斷器常用的有(you)RL1系列螺旋式(shi)(shi)熔(rong)斷器、RTO系列封(feng)閉(bi)管式(shi)(shi)熔(rong)斷器，RSO、RS3系列封(feng)閉(bi)管式(shi)(shi)快速(su)熔(rong)斷器等。

    1、RL1系列(lie)螺(luo)旋式熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)器(qi)該型(xing)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)器(qi)俗稱“螺(luo)旋保險器(qi)”，適用(yong)(yong)于(yu)交(jiao)流380V、直(zhi)流440V及以下，額(e)定電流200A以下的(de)(de)電路，RL1系列(lie)螺(luo)旋式熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)器(qi)由瓷(ci)(ci)制底座、帶螺(luo)紋螺(luo)帽、熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)管和瓷(ci)(ci)套制成(cheng)。熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)管內有(you)(you)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)絲，并裝(zhuang)滿石英砂。熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)管上(shang)蓋中有(you)(you)一熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)指示器(qi)，當熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)器(qi)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)體熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)時(shi)，指示器(qi)跳出，顯示熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)器(qi)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)，可從瓷(ci)(ci)帽頂(ding)部的(de)(de)玻璃(li)圓孔中看到(dao)(dao)。熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)管內的(de)(de)石英砂用(yong)(yong)于(yu)熄(xi)滅電弧。當熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)體熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)產生電弧時(shi)，電弧在石英砂的(de)(de)砂粒中通(tong)過(guo)，受到(dao)(dao)強烈(lie)冷卻而熄(xi)滅。因(yin)此這種熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)器(qi)具有(you)(you)較(jiao)高的(de)(de)分(fen)斷(duan)(duan)(duan)(duan)(duan)能力，極限分(fen)斷(duan)(duan)(duan)(duan)(duan)能力可達50kA。由于(yu)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)體具有(you)(you)較(jiao)大的(de)(de)熱(re)慣性，過(guo)負荷熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)斷(duan)(duan)(duan)(duan)(duan)時(shi)間較(jiao)長(chang)，因(yin)此也常(chang)用(yong)(yong)作電動機的(de)(de)保護裝(zhuang)置。

    2、RLS系(xi)列螺(luo)旋(xuan)式快速熔(rong)斷器此(ci)類熔(rong)斷器在過(guo)載倍數達到3-6倍額定電流(liu)時，熔(rong)斷時間不大于0.3-0.02s，可用作保護半導體(ti)整流(liu)元件(jian)和晶(jing)閘(zha)管的設備(bei)之用。其結(jie)構與RL1相(xiang)似，快速特(te)性通過(guo)熔(rong)體(ti)采取變截面和冶金效(xiao)應(ying)獲得。所謂變截面是(shi)將片(pian)狀熔(rong)體(ti)上沖以(yi)小(xiao)圓孔(kong)，或沖出條(tiao)形網狀，使熔(rong)體(ti)截面局部變小(xiao)，當通過(guo)過(guo)載電流(liu)時易于熔(rong)斷。

    3、RTO系列有填料封閉管式熔(rong)斷(duan)器(qi)此系列熔(rong)斷(duan)器(qi)適用(yong)于交流(liu)380V、直流(liu)440V及以下(xia)要求(qiu)分(fen)斷(duan)能力較高(gao)的(de)場合，并有一定限流(liu)特性。在供電線路、變壓器(qi)的(de)出線保護中得(de)到廣泛(fan)采用(yong)。

    RTO熔斷器的(de)結構由熔斷管、動作指示器等(deng)組成。熔斷管內裝有(you)(you)熔體(ti)和石英(ying)砂(sha)。石英(ying)砂(sha)的(de)作用是(shi)，當熔體(ti)熔斷產生電(dian)(dian)弧時，石英(ying)砂(sha)能(neng)吸收(shou)電(dian)(dian)弧能(neng)量(liang)，冷卻電(dian)(dian)弧，使電(dian)(dian)弧快速熄滅，從而提高了分(fen)斷電(dian)(dian)路的(de)能(neng)力(li)。熔體(ti)由紫銅片沖成柵狀，中間部(bu)分(fen)用錫橋連接，具有(you)(you)良(liang)好的(de)安(an)秒(miao)特性。