電機 - 電機常見故障檢修
在(zai)家用電(dian)器(qi)設備中，如電(dian)扇(shan)、電(dian)冰箱、洗衣機、抽油煙機、吸塵器(qi)等，其工(gong)作動力(li)均(jun)采用單(dan)相交流(liu)電(dian)動機。這種電(dian)動機結構較簡單(dan)，因此有(you)些常見故(gu)障可在(zai)業余條件下進行(xing)修(xiu)復。
1、電(dian)動機通電(dian)后不啟動
該故障(zhang)除了電(dian)(dian)(dian)源回路(lu)、電(dian)(dian)(dian)機(ji)繞組不良外，大多是電(dian)(dian)(dian)機(ji)的啟(qi)動電(dian)(dian)(dian)路(lu)異常。電(dian)(dian)(dian)扇、排風扇、洗衣機(ji)等電(dian)(dian)(dian)機(ji)一(yi)般采(cai)用(yong)電(dian)(dian)(dian)容器啟(qi)動運(yun)轉；而電(dian)(dian)(dian)冰箱(xiang)、冷(leng)柜等的電(dian)(dian)(dian)機(ji)多采(cai)用(yong)電(dian)(dian)(dian)阻分(fen)相啟(qi)動運(yun)轉，一(yi)旦啟(qi)動電(dian)(dian)(dian)路(lu)中(zhong)的電(dian)(dian)(dian)容器或分(fen)相電(dian)(dian)(dian)阻損(sun)壞，電(dian)(dian)(dian)機(ji)就不能正常運(yun)轉，檢(jian)修時應(ying)先排除啟(qi)動電(dian)(dian)(dian)路(lu)故障(zhang)后再查電(dian)(dian)(dian)機(ji)故障(zhang)。
若啟動電路(lu)正常，則(ze)可能是電動機內部(bu)繞(rao)組局部(bu)短路(lu)或斷路(lu)，可用(yong)萬用(yong)表R×1擋測(ce)各繞(rao)組電阻值來判斷。
如(ru)電冰箱壓縮機(ji)電機(ji)，正常(chang)情況下啟動繞(rao)(rao)組(zu)電阻(zu)值約為(wei)23Ω，運(yun)行繞(rao)(rao)組(zu)電阻(zu)值為(wei)10Ω左右(you)，起(qi)動和(he)運(yun)行串接繞(rao)(rao)組(zu)正常(chang)阻(zu)值應為(wei)兩(liang)者之和(he)。
2、電動機轉速(su)慢而無力
電(dian)(dian)(dian)動機在通電(dian)(dian)(dian)后轉(zhuan)(zhuan)(zhuan)速慢(man)而無力時，對于電(dian)(dian)(dian)容啟動式電(dian)(dian)(dian)機大(da)多為電(dian)(dian)(dian)容器容量不足、漏電(dian)(dian)(dian)嚴重或電(dian)(dian)(dian)源電(dian)(dian)(dian)壓過低；此(ci)外鼠籠轉(zhuan)(zhuan)(zhuan)子鋁條部分如果有嚴重的缺(que)損(sun)及斷(duan)條情況，特別是(shi)洗衣機電(dian)(dian)(dian)機經常啟動和正(zheng)反交替運轉(zhuan)(zhuan)(zhuan)，轉(zhuan)(zhuan)(zhuan)子鋁條較大(da)的感(gan)應電(dian)(dian)(dian)流(liu)易使轉(zhuan)(zhuan)(zhuan)子鋁條斷(duan)裂(lie)，也導致運轉(zhuan)(zhuan)(zhuan)慢(man)而無力。
當發現鋁(lv)條有裂縫(feng)時，可(ke)(ke)用(yong)手電鉆在裂縫(feng)間鉆一(yi)個小孔(kong)(kong)，用(yong)相(xiang)應的(de)鋁(lv)絲(si)條嵌入孔(kong)(kong)內，然后將其敲平鉚(liu)死(si)，最后用(yong)鋼銼和砂紙打磨平整光(guang)滑(hua)即可(ke)(ke)。若鋁(lv)條斷裂面(mian)較大(da)時，有條件的(de)可(ke)(ke)采用(yong)鋁(lv)絲(si)氣(qi)焊的(de)方法加以修補(bu)。
3、電動機(ji)外(wai)殼帶電
一般要求電機泄漏電流不應大于0．8mA，以(yi)保證人身安(an)全。
電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)外殼漏電(dian)(dian)(dian)(dian)(dian)(dian)的主要(yao)原因有電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)內某引(yin)出線(xian)絕緣破損并碰觸(chu)殼體(ti)；電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)繞組(zu)局(ju)部燒毀(hui)引(yin)起定子(zi)與外殼間(jian)漏電(dian)(dian)(dian)(dian)(dian)(dian)。較(jiao)多見的是長(chang)期(qi)處于高(gao)濕環境(jing)，導致電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)受潮絕緣降低而(er)使機(ji)殼帶電(dian)(dian)(dian)(dian)(dian)(dian)。此時，可用搖表測量電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)各繞組(zu)與機(ji)殼間(jian)的絕緣電(dian)(dian)(dian)(dian)(dian)(dian)阻值，若(ruo)在2MΩ以下(xia)，則說明電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)已受潮嚴重，應(ying)將電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)定子(zi)繞組(zu)進(jin)行烘烤去潮處理。
4、電(dian)動機運轉時溫升加劇(ju)
各類家用(yong)單相電(dian)(dian)動機(ji)在正常工(gong)(gong)作(zuo)(zuo)狀態(tai)下，其(qi)電(dian)(dian)機(ji)殼體表(biao)(biao)面溫(wen)度(du)一般(ban)比環境(jing)溫(wen)度(du)高20℃左右，最高溫(wen)升不(bu)應高于(yu)70℃。如果(guo)電(dian)(dian)機(ji)工(gong)(gong)作(zuo)(zuo)幾分鐘后出現殼體表(biao)(biao)面溫(wen)度(du)劇(ju)升，且機(ji)內散發焦油味甚至冒(mao)煙，則為(wei)電(dian)(dian)機(ji)過熱(re)故障(zhang)。
電機(ji)(ji)(ji)(ji)過熱溫升的原(yuan)因，主要(yao)有電機(ji)(ji)(ji)(ji)自身(shen)質量(liang)問(wen)題；電機(ji)(ji)(ji)(ji)長期(qi)處于超負荷運(yun)行狀(zhuang)態（傳(chuan)動機(ji)(ji)(ji)(ji)構故障引起(qi)電機(ji)(ji)(ji)(ji)負荷大(da)）；電機(ji)(ji)(ji)(ji)散熱條(tiao)件差；電機(ji)(ji)(ji)(ji)繞組局部短路等。其(qi)中較常(chang)見的是繞組匝間 短路，可拆(chai)開機(ji)(ji)(ji)(ji)殼檢查繞組。如果(guo)線(xian)包(bao)無(wu)燒(shao)(shao)毀現(xian)象，可將定子(zi)重新進行浸漆絕緣處理，然(ran)后烘干(gan)。若線(xian)包(bao)有局部燒(shao)(shao)毀，那只有更換繞組線(xian)包(bao)。
5、電動機運(yun)行(xing)噪聲大
電(dian)機(ji)工作(zuo)噪(zao)(zao)(zao)聲(sheng)大，一般有兩種原因(yin)，一是機(ji)械噪(zao)(zao)(zao)聲(sheng)，主要是電(dian)機(ji)軸(zhou)承(cheng)磨損和缺油(you)，產生(sheng)硬摩擦噪(zao)(zao)(zao)聲(sheng)。對(dui)(dui)此(ci)可(ke)(ke)清(qing)洗后加入潤滑脂減少噪(zao)(zao)(zao)聲(sheng)。當轉(zhuan)子軸(zhou)與軸(zhou)承(cheng)松動或(huo)端蓋松動時(shi)，也會使(shi)電(dian)機(ji)在旋轉(zhuan)時(shi)產生(sheng)軸(zhou)向竄動發(fa)出(chu)噪(zao)(zao)(zao)聲(sheng)。也有一些裝配(pei)質(zhi)量差(cha)的電(dian)機(ji)，軸(zhou)承(cheng)室不同心(xin)，電(dian)機(ji)徑(jing)向間隙不均(jun)勻等均(jun)會產生(sheng)異常噪(zao)(zao)(zao)聲(sheng)。對(dui)(dui)此(ci)，只(zhi)要拆下(xia)外蓋和后內蓋，取出(chu)轉(zhuan)子和定子座，重新敲鉚內蓋的中心(xin)軸(zhou)即可(ke)(ke)應急修復。
另外，一些罩極式(shi)電機的短路(lu)環(huan)松動(dong)或鐵(tie)心松動(dong)而(er)產生電磁噪(zao)聲，應采取夾緊措施。
6、其他方面故(gu)障
工業用電機(ji)在(zai)長(chang)期運行(xing)過程(cheng)中，受(shou)應(ying)(ying)力所(suo)致常(chang)會出(chu)現磨損(sun)類故(gu)障：如減速機(ji)的連接(jie)(jie)器傳遞扭矩較大，法蘭面上的連接(jie)(jie)孔磨損(sun)造成(cheng)(cheng)的傳遞扭矩不(bu)(bu)平穩；電機(ji)軸(zhou)軸(zhou)承損(sun)壞(huai)后(hou)，造成(cheng)(cheng)的軸(zhou)承位磨損(sun)；軸(zhou)頭、鍵槽間的磨損(sun)等(deng)等(deng)。該類問題發生后(hou)，傳統方(fang)法多以補焊或(huo)刷鍍后(hou)機(ji)加工修(xiu)復(fu)(fu)(fu)(fu)為(wei)主，但兩者(zhe)均存在(zai)一(yi)定弊端：補焊高溫產生的熱(re)應(ying)(ying)力無(wu)法完全消(xiao)除，易造成(cheng)(cheng)材(cai)質損(sun)傷，使部件(jian)出(chu)現彎曲(qu)或(huo)斷裂(lie)；而電刷鍍受(shou)涂層厚(hou)度(du)(du)限制(zhi)，容易剝落，且以上兩種方(fang)法都是(shi)用金屬(shu)(shu)修(xiu)復(fu)(fu)(fu)(fu)金屬(shu)(shu)，無(wu)法改變“硬對硬”的配合關系，在(zai)各(ge)力綜合作用下，仍會造成(cheng)(cheng)再(zai)次(ci)磨損(sun)。目前以非(fei)金屬(shu)(shu)修(xiu)復(fu)(fu)(fu)(fu)金屬(shu)(shu)的方(fang)法主要是(shi)高分子復(fu)(fu)(fu)(fu)合材(cai)料修(xiu)復(fu)(fu)(fu)(fu)。材(cai)料具(ju)有超(chao)強(qiang)的粘著力，優異的抗壓(ya)強(qiang)度(du)(du)等(deng)綜合性能，應(ying)(ying)用高分子復(fu)(fu)(fu)(fu)合材(cai)料修(xiu)復(fu)(fu)(fu)(fu)，既無(wu)補焊熱(re)應(ying)(ying)力影響(xiang)，修(xiu)復(fu)(fu)(fu)(fu)厚(hou)度(du)(du)也(ye)不(bu)(bu)受(shou)限制(zhi)，同時產品所(suo)具(ju)有的金屬(shu)(shu)材(cai)料不(bu)(bu)具(ju)備(bei)的退讓性，可吸收(shou)設(she)備(bei)的沖擊震(zhen)動，避免再(zai)次(ci)磨損(sun)的可能，并延長(chang)了設(she)備(bei)部件(jian)的使用壽命(ming)，為(wei)企(qi)業節省大量的停機(ji)時間，創(chuang)造巨大的經濟價值。
