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(dang)有市(shi)電(dian)(dian)(dian)(dian)(dian)時(shi)．通過(guo)變壓器(qi)B降(jiang)(jiang)壓、整流、濾波(bo)．此時(shi)6V的直流繼(ji)電(dian)(dian)(dian)(dian)(dian)吸(xi)合(he)，常(chang)(chang)開觸點閉合(he)，使整流后的直流電(dian)(dian)(dian)(dian)(dian)通過(guo)R1降(jiang)(jiang)壓向電(dian)(dian)(dian)(dian)(dian)瓶充電(dian)(dian)(dian)(dian)(dian)，LED作電(dian)(dian)(dian)(dian)(dian)源指示燈。當(dang)市(shi)電(dian)(dian)(dian)(dian)(dian)停電(dian)(dian)(dian)(dian)(dian)時(shi)，6V的繼(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)失(shi)電(dian)(dian)(dian)(dian)(dian)．常(chang)(chang)開點斷開，接(jie)通常(chang)(chang)閉點，應急(ji)燈泡ZD接(jie)到電(dian)(dian)(dian)(dian)(dian)瓶端．得電(dian)(dian)(dian)(dian)(dian)發光(guang)起到應急(ji)照明作用。市(shi)電(dian)(dian)(dian)(dian)(dian)恢(hui)復時(shi)．回復到上述過(guo)程。

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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。這種燈較簡易價格低．然而(er)故障也出(chu)現得(de)多。

消防應急燈常見故障及維修

由于(yu)電(dian)瓶(ping)長期充電(dian)。又無充滿保護電(dian)路(lu)．故最(zui)容(rong)易壞，其次是變壓器，再就是驅(qu)動(dong)三(san)極管Q2(或Q3)，如果燈泡(pao)長期被點亮。管于(yu)發(fa)熱(re)，也容(rong)易損壞。一(yi)般更換這幾個元件便能正常(chang)工作。

當(dang)市電(dian)(dian)(dian)(dian)(dian)(dian)正常供電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)。通過變壓器降壓、整流(liu)、濾波，在C1上得到大約(yue)13V的(de)直流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)壓。該電(dian)(dian)(dian)(dian)(dian)(dian)壓經(jing)R3、Q1、D6給(gei)電(dian)(dian)(dian)(dian)(dian)(dian)瓶充電(dian)(dian)(dian)(dian)(dian)(dian)。Q1的(de)基極接(jie)有(you)穩壓二(er)極管(guan)DZ1，電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)R4既是Q1基極的(de)偏流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)，又是穩壓管(guan)的(de)限(xian)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)，使Q1基極約(yue)為8.9V，這樣(yang)充電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓受到限(xian)制，最高為7.6V．可保護電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)。其充電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)隨著(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)瓶的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓而變化，電(dian)(dian)(dian)(dian)(dian)(dian)壓越(yue)低(di)充電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)越(yue)大，反(fan)之越(yue)小。在充電(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)，Q2飽(bao)和導通，Q3由于D7、R10的(de)作用而截(jie)(jie)止，Q4也截(jie)(jie)止，所以照明(ming)燈ZD1、ZD2不亮。

當220v交流電(dian)(dian)因(yin)故(gu)停(ting)(ting)電(dian)(dian)時(shi)，變壓(ya)(ya)器B1次級(ji)無輸出(chu)電(dian)(dian)．電(dian)(dian)路(lu)中直流13V電(dian)(dian)壓(ya)(ya)消失，D7正極(ji)(ji)無電(dian)(dian)壓(ya)(ya)，由(you)于Q2在(zai)停(ting)(ting)電(dian)(dian)前處于飽和導通(tong)(tong)(tong)狀態，所以(yi)Q3立即導通(tong)(tong)(tong)，Q4基極(ji)(ji)電(dian)(dian)位(wei)升高(gao)，Q4也隨之(zhi)導通(tong)(tong)(tong)，照(zhao)(zhao)明(ming)(ming)燈(deng)DZ1、DZ2被(bei)點亮(liang)。Q4導通(tong)(tong)(tong)后其集電(dian)(dian)極(ji)(ji)為低(di)電(dian)(dian)位(wei)，由(you)于R1跨(kua)接在(zai)Q4集電(dian)(dian)極(ji)(ji)與Q3基極(ji)(ji)之(zhi)間，Q3基極(ji)(ji)電(dian)(dian)位(wei)下(xia)降，維持Q3的導通(tong)(tong)(tong)狀態，照(zhao)(zhao)明(ming)(ming)燈(deng)一(yi)直被(bei)點亮(liang)。紅色(se)(se)LED作(zuo)為充電(dian)(dian)指示(shi)(shi)燈(deng)，綠色(se)(se)LED作(zuo)為主電(dian)(dian)源指示(shi)(shi)燈(deng)。紅燈(deng)亮(liang)表(biao)(biao)示(shi)(shi)電(dian)(dian)瓶正在(zai)充電(dian)(dian)，綠燈(deng)亮(liang)表(biao)(biao)示(shi)(shi)有(you)交流220V電(dian)(dian)壓(ya)(ya)。0N／OFF為照(zhao)(zhao)明(ming)(ming)燈(deng)的開關(guan)按鈕，220V交流電(dian)(dian)源停(ting)(ting)電(dian)(dian)時(shi)．可以(yi)通(tong)(tong)(tong)過此按鈕打開或關(guan)閉照(zhao)(zhao)明(ming)(ming)燈(deng)。

當應急燈出(chu)故障時(shi)．可先觀察(cha)兩指(zhi)示燈的(de)工作(zuo)狀態。交(jiao)流(liu)220V供(gong)電(dian)(dian)正常(chang)時(shi)．綠色(se)指(zhi)示燈應(ying)(ying)(ying)亮(liang)(liang)，電(dian)(dian)瓶充(chong)電(dian)(dian)紅色(se)指(zhi)示燈也應(ying)(ying)(ying)亮(liang)(liang)。如(ru)果綠燈不(bu)亮(liang)(liang)，則應(ying)(ying)(ying)檢(jian)查(cha)變(bian)壓(ya)(ya)(ya)(ya)器次級是(shi)否有9V交(jiao)流(liu)電(dian)(dian)壓(ya)(ya)(ya)(ya)，電(dian)(dian)容C1兩端(duan)應(ying)(ying)(ying)有13V左(zuo)(zuo)右(you)的(de)直流(liu)電(dian)(dian)。如(ru)果兩處都沒有電(dian)(dian)壓(ya)(ya)(ya)(ya)。一(yi)般是(shi)變(bian)壓(ya)(ya)(ya)(ya)器B1損壞。電(dian)(dian)源(綠色(se))指(zhi)示燈亮(liang)(liang)，充(chong)電(dian)(dian)(紅色(se))指(zhi)示燈不(bu)亮(liang)(liang)，可測Q1發射極有無(wu)(wu)7V左(zuo)(zuo)右(you)電(dian)(dian)壓(ya)(ya)(ya)(ya)，如(ru)無(wu)(wu)電(dian)(dian)壓(ya)(ya)(ya)(ya)，則應(ying)(ying)(ying)檢(jian)查(cha)Q1之(zhi)前的(de)相應(ying)(ying)(ying)元件。檢(jian)修中，可斷開電(dian)(dian)瓶正極，測量應(ying)(ying)(ying)急燈的(de)開路(lu)充(chong)電(dian)(dian)電(dian)(dian)壓(ya)(ya)(ya)(ya)與(yu)通路(lu)充(chong)電(dian)(dian)電(dian)(dian)壓(ya)(ya)(ya)(ya)，正常(chang)時(shi)應(ying)(ying)(ying)為7V左(zuo)(zuo)右(you)，充(chong)電(dian)(dian)電(dian)(dian)流(liu)約為450mA。如(ru)果電(dian)(dian)壓(ya)(ya)(ya)(ya)過高(gao)，則應(ying)(ying)(ying)查(cha)Q1是(shi)否擊穿短(duan)路(lu)，DZ1、R14是(shi)否開路(lu)，過高(gao)的(de)充(chong)電(dian)(dian)電(dian)(dian)壓(ya)(ya)(ya)(ya)，將造成電(dian)(dian)瓶過充(chong)損壞。

交流220V停電時．照(zhao)明燈ZD1、ZD2不亮(liang)．首先查燈泡是否(fou)損壞．再檢查三極管(guan)Q2、Q3、Q4及相(xiang)關元(yuan)件(jian)是否(fou)損壞；電瓶老(lao)化(hua)等。