工控電(dian)路板電(dian)容損壞的故(gu)障特點(dian)及維修

電(dian)容(rong)損(sun)壞引(yin)發的(de)故(gu)障在(zai)電(dian)子設備中是Z高的(de)，其(qi)中尤其(qi)以(yi)電(dian)解電(dian)容(rong)的(de)損(sun)壞Z為常見。

電容損(sun)壞表現為：1.容量變(bian)小;2.完全失去容量;3.漏電;4.短路。

電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)在(zai)(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中所起的(de)(de)(de)(de)作(zuo)用不同(tong)，引起的(de)(de)(de)(de)故障也各有(you)特(te)點。在(zai)(zai)(zai)工(gong)控電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)板中，數字(zi)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)占絕大多(duo)(duo)數，電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)多(duo)(duo)用做電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)濾(lv)波，用做信(xin)號(hao)耦合和(he)振(zhen)蕩電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)較少。用在(zai)(zai)(zai)開(kai)(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)中的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)如果(guo)損壞，則(ze)開(kai)(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)可(ke)能不起振(zhen)，沒有(you)電(dian)(dian)(dian)(dian)(dian)(dian)壓輸出(chu)(chu);或(huo)者輸出(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)壓濾(lv)波不好(hao)，電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)因電(dian)(dian)(dian)(dian)(dian)(dian)壓不穩而發(fa)生邏(luo)輯混亂，表現為機器工(gong)作(zuo)時(shi)好(hao)時(shi)壞或(huo)開(kai)(kai)不了(le)機，如果(guo)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)并在(zai)(zai)(zai)數字(zi)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)正負極(ji)之間(jian)，故障表現同(tong)上。這(zhe)在(zai)(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)腦主板上表現尤其(qi)明顯，很(hen)多(duo)(duo)電(dian)(dian)(dian)(dian)(dian)(dian)腦用了(le)幾(ji)年就出(chu)(chu)現有(you)時(shi)開(kai)(kai)不了(le)機，有(you)時(shi)又可(ke)以開(kai)(kai)機的(de)(de)(de)(de)現象(xiang)，打開(kai)(kai)機箱，往往可(ke)以看見有(you)電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)鼓包的(de)(de)(de)(de)現象(xiang)，如果(guo)將電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)拆下(xia)來量一(yi)下(xia)容(rong)(rong)(rong)量，發(fa)現比實際值要低(di)很(hen)多(duo)(duo)。

電(dian)(dian)容(rong)(rong)(rong)的(de)(de)壽(shou)命與(yu)環境溫度直接有(you)(you)關，環境溫度越(yue)高，電(dian)(dian)容(rong)(rong)(rong)壽(shou)命越(yue)短(duan)。這個規律不但(dan)適(shi)(shi)用(yong)電(dian)(dian)解電(dian)(dian)容(rong)(rong)(rong)，也(ye)適(shi)(shi)用(yong)其它(ta)電(dian)(dian)容(rong)(rong)(rong)。所以在尋找故障電(dian)(dian)容(rong)(rong)(rong)時應(ying)重點檢查(cha)和熱(re)源(yuan)(yuan)靠得比(bi)較(jiao)近(jin)的(de)(de)電(dian)(dian)容(rong)(rong)(rong)，如散熱(re)片(pian)旁(pang)(pang)及(ji)大(da)功率元器件旁(pang)(pang)的(de)(de)電(dian)(dian)容(rong)(rong)(rong)，離其越(yue)近(jin)，損壞(huai)的(de)(de)可能性就(jiu)越(yue)大(da)。曾(ceng)經修過一臺X光探傷儀(yi)的(de)(de)電(dian)(dian)源(yuan)(yuan)，用(yong)戶反映有(you)(you)煙從電(dian)(dian)源(yuan)(yuan)里冒(mao)出(chu)來，拆開機箱后(hou)發(fa)現有(you)(you)一只(zhi)1000uF/350V的(de)(de)大(da)電(dian)(dian)容(rong)(rong)(rong)有(you)(you)油(you)質一樣的(de)(de)東西(xi)流(liu)出(chu)來，拆下來一量容(rong)(rong)(rong)量只(zhi)有(you)(you)幾十uF，還發(fa)現只(zhi)有(you)(you)這只(zhi)電(dian)(dian)容(rong)(rong)(rong)與(yu)整流(liu)橋的(de)(de)散熱(re)片(pian)離得Z近(jin)，其它(ta)離得遠的(de)(de)就(jiu)完好無損，容(rong)(rong)(rong)量正(zheng)常。另外有(you)(you)瓷片(pian)電(dian)(dian)容(rong)(rong)(rong)出(chu)現短(duan)路的(de)(de)情況(kuang)，也(ye)發(fa)現電(dian)(dian)容(rong)(rong)(rong)離發(fa)熱(re)部件比(bi)較(jiao)近(jin)。所以在檢修查(cha)找時應(ying)有(you)(you)所側重。

有些電容漏電比較嚴重，用手(shou)指觸摸時甚(shen)至會(hui)燙手(shou)，這種電容必須更(geng)換。

在檢修(xiu)時(shi)好(hao)時(shi)壞(huai)的故障(zhang)時(shi)，排除了(le)接(jie)觸不良的可能性以(yi)(yi)外，一(yi)般大部(bu)分就是電容損壞(huai)引起的故障(zhang)了(le)。所(suo)以(yi)(yi)在碰到此(ci)類故障(zhang)時(shi)，可以(yi)(yi)將電容重點檢查(cha)一(yi)下，換掉電容后往(wang)(wang)往(wang)(wang)令人驚喜(當然也要注意電容的品質，要選擇好(hao)一(yi)點的牌子，如紅寶石、黑金剛之類)。