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(ying)急燈(deng)(deng)當(dang)有市電(dian)(dian)(dian)時(shi)．通(tong)過(guo)變壓器B降壓、整(zheng)流(liu)、濾波．此(ci)時(shi)6V的直(zhi)(zhi)流(liu)繼(ji)(ji)電(dian)(dian)(dian)吸合，常開(kai)(kai)觸(chu)點(dian)(dian)閉合，使整(zheng)流(liu)后的直(zhi)(zhi)流(liu)電(dian)(dian)(dian)通(tong)過(guo)R1降壓向電(dian)(dian)(dian)瓶充電(dian)(dian)(dian)，LED作電(dian)(dian)(dian)源(yuan)指示燈(deng)(deng)。當(dang)市電(dian)(dian)(dian)停電(dian)(dian)(dian)時(shi)，6V的繼(ji)(ji)電(dian)(dian)(dian)器失(shi)電(dian)(dian)(dian)．常開(kai)(kai)點(dian)(dian)斷(duan)開(kai)(kai)，接通(tong)常閉點(dian)(dian)，應(ying)急燈(deng)(deng)泡(pao)ZD接到電(dian)(dian)(dian)瓶端(duan)．得電(dian)(dian)(dian)發光(guang)起到應(ying)急照明(ming)作用。市電(dian)(dian)(dian)恢復時(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(yi)價格低(di)．然而故障也出現得(de)多。

消防應急燈常見故障及維修

由于(yu)電瓶長(chang)期(qi)充電。又無充滿保護(hu)電路．故最(zui)容易壞，其次是(shi)變壓器，再就(jiu)是(shi)驅動三極管(guan)Q2(或Q3)，如(ru)果燈(deng)泡長(chang)期(qi)被點亮(liang)。管(guan)于(yu)發(fa)熱，也容易損(sun)壞。一般更(geng)換這幾個元件便能(neng)正常(chang)工(gong)作(zuo)。

當市電(dian)(dian)(dian)(dian)(dian)正(zheng)常供電(dian)(dian)(dian)(dian)(dian)時(shi)。通過變壓(ya)(ya)(ya)器降壓(ya)(ya)(ya)、整流、濾波，在C1上得到大(da)約(yue)13V的(de)(de)直流電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)。該電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)經(jing)R3、Q1、D6給電(dian)(dian)(dian)(dian)(dian)瓶充(chong)電(dian)(dian)(dian)(dian)(dian)。Q1的(de)(de)基極接有穩(wen)壓(ya)(ya)(ya)二極管DZ1，電(dian)(dian)(dian)(dian)(dian)阻(zu)R4既是Q1基極的(de)(de)偏流電(dian)(dian)(dian)(dian)(dian)阻(zu)，又是穩(wen)壓(ya)(ya)(ya)管的(de)(de)限流電(dian)(dian)(dian)(dian)(dian)阻(zu)，使Q1基極約(yue)為8.9V，這樣充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)受到限制，最高為7.6V．可保護電(dian)(dian)(dian)(dian)(dian)池。其充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流隨(sui)著電(dian)(dian)(dian)(dian)(dian)瓶的(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)而變化，電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)越(yue)低(di)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流越(yue)大(da)，反之越(yue)小。在充(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態，Q2飽和導通，Q3由于(yu)D7、R10的(de)(de)作用而截(jie)(jie)止，Q4也截(jie)(jie)止，所以照明燈(deng)ZD1、ZD2不亮。

當(dang)220v交流電(dian)(dian)因故停(ting)電(dian)(dian)時(shi)，變(bian)壓(ya)器B1次級(ji)無輸(shu)出(chu)電(dian)(dian)．電(dian)(dian)路中(zhong)直(zhi)流13V電(dian)(dian)壓(ya)消(xiao)失，D7正(zheng)極(ji)無電(dian)(dian)壓(ya)，由(you)于(yu)Q2在停(ting)電(dian)(dian)前處于(yu)飽和導(dao)(dao)通狀態(tai)，所以Q3立即導(dao)(dao)通，Q4基極(ji)電(dian)(dian)位(wei)(wei)升高，Q4也隨之(zhi)導(dao)(dao)通，照(zhao)明(ming)(ming)燈(deng)(deng)(deng)DZ1、DZ2被點亮。Q4導(dao)(dao)通后其集電(dian)(dian)極(ji)為(wei)低電(dian)(dian)位(wei)(wei)，由(you)于(yu)R1跨接(jie)在Q4集電(dian)(dian)極(ji)與Q3基極(ji)之(zhi)間，Q3基極(ji)電(dian)(dian)位(wei)(wei)下降，維持Q3的(de)(de)導(dao)(dao)通狀態(tai)，照(zhao)明(ming)(ming)燈(deng)(deng)(deng)一直(zhi)被點亮。紅色(se)LED作為(wei)充電(dian)(dian)指示(shi)燈(deng)(deng)(deng)，綠色(se)LED作為(wei)主電(dian)(dian)源指示(shi)燈(deng)(deng)(deng)。紅燈(deng)(deng)(deng)亮表示(shi)電(dian)(dian)瓶正(zheng)在充電(dian)(dian)，綠燈(deng)(deng)(deng)亮表示(shi)有(you)交流220V電(dian)(dian)壓(ya)。0N／OFF為(wei)照(zhao)明(ming)(ming)燈(deng)(deng)(deng)的(de)(de)開關按鈕，220V交流電(dian)(dian)源停(ting)電(dian)(dian)時(shi)．可以通過此按鈕打(da)開或關閉(bi)照(zhao)明(ming)(ming)燈(deng)(deng)(deng)。

當應急燈出故障時(shi)．可先觀察兩(liang)指(zhi)示(shi)燈(deng)(deng)的(de)工作狀態。交(jiao)流(liu)220V供電(dian)(dian)(dian)(dian)正(zheng)常時(shi)．綠色指(zhi)示(shi)燈(deng)(deng)應(ying)(ying)(ying)亮(liang)，電(dian)(dian)(dian)(dian)瓶充(chong)電(dian)(dian)(dian)(dian)紅色指(zhi)示(shi)燈(deng)(deng)也應(ying)(ying)(ying)亮(liang)。如果(guo)綠燈(deng)(deng)不亮(liang)，則(ze)(ze)應(ying)(ying)(ying)檢查變(bian)壓(ya)器次級是(shi)否有(you)9V交(jiao)流(liu)電(dian)(dian)(dian)(dian)壓(ya)，電(dian)(dian)(dian)(dian)容C1兩(liang)端(duan)應(ying)(ying)(ying)有(you)13V左右的(de)直流(liu)電(dian)(dian)(dian)(dian)。如果(guo)兩(liang)處都沒有(you)電(dian)(dian)(dian)(dian)壓(ya)。一般(ban)是(shi)變(bian)壓(ya)器B1損壞(huai)。電(dian)(dian)(dian)(dian)源(綠色)指(zhi)示(shi)燈(deng)(deng)亮(liang)，充(chong)電(dian)(dian)(dian)(dian)(紅色)指(zhi)示(shi)燈(deng)(deng)不亮(liang)，可測(ce)Q1發射極有(you)無7V左右電(dian)(dian)(dian)(dian)壓(ya)，如無電(dian)(dian)(dian)(dian)壓(ya)，則(ze)(ze)應(ying)(ying)(ying)檢查Q1之前的(de)相應(ying)(ying)(ying)元件(jian)。檢修中，可斷(duan)開電(dian)(dian)(dian)(dian)瓶正(zheng)極，測(ce)量應(ying)(ying)(ying)急(ji)燈(deng)(deng)的(de)開路(lu)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)與通路(lu)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)，正(zheng)常時(shi)應(ying)(ying)(ying)為7V左右，充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)約為450mA。如果(guo)電(dian)(dian)(dian)(dian)壓(ya)過高，則(ze)(ze)應(ying)(ying)(ying)查Q1是(shi)否擊穿短路(lu)，DZ1、R14是(shi)否開路(lu)，過高的(de)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)，將造(zao)成(cheng)電(dian)(dian)(dian)(dian)瓶過充(chong)損壞(huai)。

交(jiao)流220V停電(dian)時．照明(ming)燈(deng)ZD1、ZD2不亮．首先(xian)查(cha)燈(deng)泡是否損壞(huai)．再(zai)檢查(cha)三極管Q2、Q3、Q4及相關元件是否損壞(huai)；電(dian)瓶老化等。