消防應急燈廣泛用于公共場所的走廊、消防通道內。現在各廠礦企業、大型超市、醫院學校等都安裝了這種應急燈。市場上眾多的消防應急燈具是由消防公安及安監部門監制的產品．品種繁多，但功能基本一致。當市電停電時，消防應急燈自動點亮，來電時自動熄滅。消防應急燈作為一種備用照明設備，在燈具內裝有停電時提供電源的蓄電池G(或稱電瓶)。由于應急燈長時間與市電并聯在一起工作，所以容易出現故障。

消防應急燈電路原理

應急(ji)燈當有市(shi)電(dian)時．通(tong)過(guo)變壓器(qi)B降壓、整流、濾波．此時6V的(de)直流繼電(dian)吸合，常(chang)開(kai)觸點閉(bi)合，使整流后(hou)的(de)直流電(dian)通(tong)過(guo)R1降壓向電(dian)瓶充電(dian)，LED作電(dian)源指示燈。當市(shi)電(dian)停電(dian)時，6V的(de)繼電(dian)器(qi)失電(dian)．常(chang)開(kai)點斷開(kai)，接通(tong)常(chang)閉(bi)點，應急(ji)燈泡ZD接到電(dian)瓶端．得(de)電(dian)發光起到應急(ji)照明作用。市(shi)電(dian)恢復時．回復到上述(shu)過(guo)程(cheng)。

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消防應急燈常見故障原因

(1)電瓶長期充電，電液干枯，過早損壞。(2)變壓器長期通電過熱燒壞。(3)最常見的是繼電器線圈長期通電燒壞或其接點燒蝕。這種燈較簡易價格(ge)低．然而故障(zhang)也(ye)出現得多。

消防應急燈常見故障及維修

由于(yu)電瓶長期(qi)充(chong)電。又(you)無充(chong)滿保護電路．故最容易壞(huai)，其次(ci)是變壓器，再就是驅動(dong)三極管Q2(或Q3)，如(ru)果燈泡長期(qi)被點亮。管于(yu)發熱(re)，也容易損壞(huai)。一般(ban)更換這(zhe)幾個(ge)元件便(bian)能正(zheng)常工(gong)作(zuo)。

當市電(dian)(dian)(dian)(dian)正常供電(dian)(dian)(dian)(dian)時。通過變壓器降壓、整(zheng)流(liu)、濾波，在(zai)C1上得到(dao)大約(yue)13V的(de)直流(liu)電(dian)(dian)(dian)(dian)壓。該(gai)電(dian)(dian)(dian)(dian)壓經R3、Q1、D6給(gei)電(dian)(dian)(dian)(dian)瓶(ping)充(chong)電(dian)(dian)(dian)(dian)。Q1的(de)基(ji)(ji)極接(jie)有穩壓二(er)極管(guan)DZ1，電(dian)(dian)(dian)(dian)阻(zu)R4既是(shi)Q1基(ji)(ji)極的(de)偏流(liu)電(dian)(dian)(dian)(dian)阻(zu)，又是(shi)穩壓管(guan)的(de)限流(liu)電(dian)(dian)(dian)(dian)阻(zu)，使Q1基(ji)(ji)極約(yue)為8.9V，這樣充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓受到(dao)限制，最高為7.6V．可(ke)保護電(dian)(dian)(dian)(dian)池。其充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)隨著(zhu)電(dian)(dian)(dian)(dian)瓶(ping)的(de)電(dian)(dian)(dian)(dian)壓而(er)變化，電(dian)(dian)(dian)(dian)壓越(yue)低(di)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)越(yue)大，反(fan)之越(yue)小。在(zai)充(chong)電(dian)(dian)(dian)(dian)狀態，Q2飽和導通，Q3由于D7、R10的(de)作用而(er)截(jie)止，Q4也(ye)截(jie)止，所以照(zhao)明(ming)燈ZD1、ZD2不亮。

當(dang)220v交流電(dian)(dian)(dian)因故停(ting)電(dian)(dian)(dian)時(shi)，變壓(ya)(ya)器(qi)B1次級無(wu)(wu)輸出電(dian)(dian)(dian)．電(dian)(dian)(dian)路(lu)中直(zhi)流13V電(dian)(dian)(dian)壓(ya)(ya)消失(shi)，D7正(zheng)極(ji)無(wu)(wu)電(dian)(dian)(dian)壓(ya)(ya)，由(you)于(yu)Q2在(zai)停(ting)電(dian)(dian)(dian)前處于(yu)飽(bao)和導(dao)通狀態(tai)，所以(yi)(yi)Q3立(li)即導(dao)通，Q4基(ji)極(ji)電(dian)(dian)(dian)位(wei)(wei)升高，Q4也隨之導(dao)通，照明燈(deng)DZ1、DZ2被點(dian)亮(liang)(liang)。Q4導(dao)通后其集電(dian)(dian)(dian)極(ji)為低電(dian)(dian)(dian)位(wei)(wei)，由(you)于(yu)R1跨接在(zai)Q4集電(dian)(dian)(dian)極(ji)與Q3基(ji)極(ji)之間(jian)，Q3基(ji)極(ji)電(dian)(dian)(dian)位(wei)(wei)下降，維持Q3的(de)導(dao)通狀態(tai)，照明燈(deng)一(yi)直(zhi)被點(dian)亮(liang)(liang)。紅(hong)色(se)LED作為充(chong)電(dian)(dian)(dian)指示(shi)(shi)燈(deng)，綠色(se)LED作為主電(dian)(dian)(dian)源指示(shi)(shi)燈(deng)。紅(hong)燈(deng)亮(liang)(liang)表(biao)示(shi)(shi)電(dian)(dian)(dian)瓶(ping)正(zheng)在(zai)充(chong)電(dian)(dian)(dian)，綠燈(deng)亮(liang)(liang)表(biao)示(shi)(shi)有交流220V電(dian)(dian)(dian)壓(ya)(ya)。0N／OFF為照明燈(deng)的(de)開關按鈕，220V交流電(dian)(dian)(dian)源停(ting)電(dian)(dian)(dian)時(shi)．可以(yi)(yi)通過此按鈕打開或關閉照明燈(deng)。

當應急燈出故障時．可(ke)先觀察兩指(zhi)(zhi)示(shi)燈(deng)的(de)工(gong)作狀態。交流220V供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)正(zheng)常(chang)時．綠(lv)色(se)指(zhi)(zhi)示(shi)燈(deng)應(ying)亮(liang)(liang)(liang)，電(dian)(dian)(dian)(dian)(dian)(dian)瓶(ping)(ping)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)紅色(se)指(zhi)(zhi)示(shi)燈(deng)也應(ying)亮(liang)(liang)(liang)。如(ru)果綠(lv)燈(deng)不(bu)亮(liang)(liang)(liang)，則應(ying)檢查變壓(ya)器次(ci)級是(shi)否(fou)(fou)有(you)(you)9V交流電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，電(dian)(dian)(dian)(dian)(dian)(dian)容C1兩端應(ying)有(you)(you)13V左右的(de)直(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)。如(ru)果兩處都沒有(you)(you)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。一般是(shi)變壓(ya)器B1損壞(huai)。電(dian)(dian)(dian)(dian)(dian)(dian)源(綠(lv)色(se))指(zhi)(zhi)示(shi)燈(deng)亮(liang)(liang)(liang)，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(紅色(se))指(zhi)(zhi)示(shi)燈(deng)不(bu)亮(liang)(liang)(liang)，可(ke)測(ce)Q1發射極(ji)有(you)(you)無7V左右電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，如(ru)無電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，則應(ying)檢查Q1之前的(de)相應(ying)元件。檢修中，可(ke)斷開電(dian)(dian)(dian)(dian)(dian)(dian)瓶(ping)(ping)正(zheng)極(ji)，測(ce)量應(ying)急(ji)燈(deng)的(de)開路(lu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)與(yu)通路(lu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，正(zheng)常(chang)時應(ying)為7V左右，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流約為450mA。如(ru)果電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)過(guo)高，則應(ying)查Q1是(shi)否(fou)(fou)擊穿短(duan)路(lu)，DZ1、R14是(shi)否(fou)(fou)開路(lu)，過(guo)高的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，將造成電(dian)(dian)(dian)(dian)(dian)(dian)瓶(ping)(ping)過(guo)充(chong)(chong)(chong)損壞(huai)。

交流220V停電(dian)時．照(zhao)明燈ZD1、ZD2不(bu)亮．首先查燈泡是(shi)否(fou)損壞．再檢查三極管Q2、Q3、Q4及相(xiang)關(guan)元件是(shi)否(fou)損壞；電(dian)瓶老化等(deng)。