如何選購電動機 電動機的維護保養步驟

一、電動機的選購。電動機的選購應遵循以下步驟：

⑴查看外觀：電(dian)動(dong)(dong)(dong)機(ji)表(biao)面(mian)油漆層(ceng)應(ying)光滑(hua)平整，銘牌安裝(zhuang)端(duan)正，標(biao)志(zhi)齊(qi)全；封(feng)閉(bi)式電(dian)動(dong)(dong)(dong)機(ji)座散(san)熱(re)筋應(ying)完(wan)整無損，附件齊(qi)全；⑵手(shou)(shou)動(dong)(dong)(dong)旋轉：用(yong)(yong)手(shou)(shou)轉動(dong)(dong)(dong)電(dian)軸(zhou)、轉動(dong)(dong)(dong)應(ying)很靈活(huo)，慣動(dong)(dong)(dong)量(liang)較好，軸(zhou)向基本(ben)無竄(cuan)動(dong)(dong)(dong)量(liang)；⑶診聽軸(zhou)承：通電(dian)運行15-25分鐘，軸(zhou)承應(ying)平穩(wen)輕快，無停滯現象。聲音(yin)均勻(yun)和(he)諧；軸(zhou)承溫度不高，沒有漏油、甩油現象；運行停止后，用(yong)(yong)手(shou)(shou)摸電(dian)動(dong)(dong)(dong)機(ji)座和(he)端(duan)蓋(gai)不感到發(fa)熱(re)；⑷檢查接(jie)線(xian)(xian)(xian)：打開接(jie)線(xian)(xian)(xian)盒看各相(xiang)(xiang)相(xiang)(xiang)線(xian)(xian)(xian)標(biao)志(zhi)是否(fou)清晰完(wan)整，聯絡片是否(fou)壓(ya)(ya)實壓(ya)(ya)緊，螺母是否(fou)齊(qi)全；⑸測(ce)量(liang)電(dian)阻(zu)(zu)：用(yong)(yong)額定電(dian)壓(ya)(ya)500V的(de)手(shou)(shou)動(dong)(dong)(dong)式兆歐(ou)表(biao)，測(ce)量(liang)出線(xian)(xian)(xian)端(duan)相(xiang)(xiang)線(xian)(xian)(xian)與(yu)相(xiang)(xiang)線(xian)(xian)(xian)之間(jian)及線(xian)(xian)(xian)對機(ji)座之間(jian)的(de)絕緣(yuan)電(dian)阻(zu)(zu)，正常電(dian)機(ji)的(de)絕緣(yuan)電(dian)阻(zu)(zu)應(ying)大于1兆歐(ou)。⑹測(ce)量(liang)電(dian)流(liu)(liu)。在運行中(zhong)用(yong)(yong)鉗型電(dian)流(liu)(liu)表(biao)測(ce)電(dian)機(ji)空載時(shi)各相(xiang)(xiang)的(de)電(dian)流(liu)(liu)，三(san)相(xiang)(xiang)電(dian)流(liu)(liu)中(zhong)任何(he)一相(xiang)(xiang)與(yu)三(san)相(xiang)(xiang)平均值的(de)偏差不得大于平均值的(de)10%，空載電(dian)流(liu)(liu)一般為額定電(dian)流(liu)(liu)的(de)25-50%。

二、電動機的維護。實踐證明，電動機的維護重點在于防止電機燒毀，下述方法是行之有效的：

1、保(bao)持(chi)啟(qi)(qi)動(dong)(dong)(dong)設(she)備(bei)(bei)技(ji)術狀(zhuang)(zhuang)態完好(hao)，電(dian)(dian)動(dong)(dong)(dong)機啟(qi)(qi)動(dong)(dong)(dong)設(she)備(bei)(bei)技(ji)術狀(zhuang)(zhuang)態的好(hao)壞(huai)直接(jie)關系到能(neng)否(fou)順(shun)利(li)(li)啟(qi)(qi)動(dong)(dong)(dong)。實踐(jian)表明(ming)，絕(jue)大(da)多數燒(shao)毀(hui)的電(dian)(dian)動(dong)(dong)(dong)機都是(shi)啟(qi)(qi)動(dong)(dong)(dong)不(bu)順(shun)利(li)(li)而(er)燒(shao)毀(hui)的，如啟(qi)(qi)動(dong)(dong)(dong)設(she)備(bei)(bei)技(ji)術狀(zhuang)(zhuang)態不(bu)良引發(fa)的缺(que)相啟(qi)(qi)動(dong)(dong)(dong)；接(jie)觸(chu)(chu)(chu)(chu)器(qi)觸(chu)(chu)(chu)(chu)頭拉(la)弧(hu)、打火而(er)導致電(dian)(dian)壓、電(dian)(dian)流(liu)(liu)大(da)幅(fu)度改變(bian)等。保(bao)持(chi)啟(qi)(qi)動(dong)(dong)(dong)設(she)備(bei)(bei)技(ji)術狀(zhuang)(zhuang)態良好(hao)的措(cuo)施是(shi)：經常做檢(jian)(jian)查、清(qing)潔、緊固工作(zuo)。若接(jie)觸(chu)(chu)(chu)(chu)器(qi)觸(chu)(chu)(chu)(chu)頭不(bu)清(qing)潔，氧(yang)化燒(shao)蝕嚴(yan)重(zhong)，則(ze)會(hui)產生接(jie)觸(chu)(chu)(chu)(chu)電(dian)(dian)阻增大(da)，引起(qi)發(fa)熱、燒(shao)蝕觸(chu)(chu)(chu)(chu)點(dian)，從而(er)形成缺(que)相運行而(er)燒(shao)毀(hui)電(dian)(dian)機繞組；接(jie)觸(chu)(chu)(chu)(chu)器(qi)吸(xi)合線(xian)圈(quan)鐵芯(xin)有(you)銹蝕和灰塵(chen)，會(hui)使吸(xi)合不(bu)嚴(yan)而(er)發(fa)出(chu)強烈(lie)噪聲，并增大(da)線(xian)圈(quan)電(dian)(dian)流(liu)(liu)，直至燒(shao)毀(hui)線(xian)圈(quan)。因此，電(dian)(dian)氣控制柜應設(she)在(zai)干燥、通風和便于操作(zuo)的位置；還要(yao)定(ding)期除塵(chen)、清(qing)理觸(chu)(chu)(chu)(chu)點(dian)；線(xian)圈(quan)鐵芯(xin)要(yao)增加防(fang)銹措(cuo)施；要(yao)經常緊固各連接(jie)部件(jian)；檢(jian)(jian)查接(jie)觸(chu)(chu)(chu)(chu)器(qi)觸(chu)(chu)(chu)(chu)點(dian)，保(bao)證(zheng)接(jie)觸(chu)(chu)(chu)(chu)良好(hao)，機構動(dong)(dong)(dong)作(zuo)應靈活、準(zhun)確，這些是(shi)保(bao)證(zheng)啟(qi)(qi)動(dong)(dong)(dong)順(shun)利(li)(li)的必然(ran)條(tiao)件(jian)。

2、保持電(dian)動(dong)機清潔和良好的冷(leng)卻(que)環境，在電(dian)動(dong)機的進風(feng)口(kou)處，必須(xu)經常保持清潔。進風(feng)口(kou)的周圍(wei)不得有(you)塵(chen)土、油(you)污(wu)、水漬和其它秸稈雜(za)物，以防止這類(lei)東西吸入電(dian)機內部，形成短路(lu)介質或損傷電(dian)機繞組絕緣層(ceng)；或阻斷電(dian)機的通風(feng)冷(leng)卻(que)而溫度升高，導致燒毀。

3、保(bao)持電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)在額定電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)下(xia)(xia)工作(zuo)(zuo)(zuo)，避免農(nong)用電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)的(de)(de)(de)過(guo)(guo)(guo)載運行。當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)處于過(guo)(guo)(guo)載狀態運行時，電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)轉(zhuan)速下(xia)(xia)降，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)增大，溫度(du)升高(gao)，繞組(zu)線圈過(guo)(guo)(guo)熱。其主要原因是(shi)(shi)(shi)拖動(dong)(dong)(dong)(dong)負(fu)荷過(guo)(guo)(guo)大，電(dian)(dian)(dian)(dian)(dian)(dian)壓過(guo)(guo)(guo)低或被(bei)拖動(dong)(dong)(dong)(dong)的(de)(de)(de)機(ji)(ji)械(xie)卡(ka)(ka)滯(zhi)等造成的(de)(de)(de)；若過(guo)(guo)(guo)載時間稍長，過(guo)(guo)(guo)載電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)從電(dian)(dian)(dian)(dian)(dian)(dian)網中吸收大量(liang)有功(gong)功(gong)率(lv)，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)便急劇增加，隨之溫度(du)上升。在高(gao)溫下(xia)(xia)運行的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)，絕緣材料(liao)易老化失效而燒毀(hui)繞組(zu)線圈，這是(shi)(shi)(shi)燒毀(hui)電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)的(de)(de)(de)主要原因。因此(ci)，一要經常注(zhu)意(yi)檢查(cha)(cha)機(ji)(ji)組(zu)傳動(dong)(dong)(dong)(dong)裝置是(shi)(shi)(shi)否運轉(zhuan)靈活、可靠，隨時檢查(cha)(cha)、調整傳動(dong)(dong)(dong)(dong)皮帶(dai)松緊度(du)，防止卡(ka)(ka)滯(zhi)；二(er)要注(zhu)意(yi)作(zuo)(zuo)(zuo)業機(ji)(ji)械(xie)不要較長時間超(chao)負(fu)荷工作(zuo)(zuo)(zuo)；三要保(bao)持電(dian)(dian)(dian)(dian)(dian)(dian)壓穩定，尤(you)其不得低壓運轉(zhuan)，從而確(que)保(bao)電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機(ji)(ji)在額定電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)下(xia)(xia)正(zheng)常工作(zuo)(zuo)(zuo)。

4、保(bao)持相間電(dian)流平衡。農用三相異步電(dian)動(dong)(dong)機，其中任(ren)何一相的(de)電(dian)流值與其他(ta)兩相電(dian)流平均值之差不得超過10%，這是保(bao)證電(dian)動(dong)(dong)機安全運(yun)轉的(de)必要條件。如(ru)果(guo)這個(ge)差值超過10%，則(ze)(ze)表明(ming)電(dian)動(dong)(dong)機已經出(chu)現(xian)故(gu)障(zhang)，必須(xu)立即停機查明(ming)原因，并排除故(gu)障(zhang)后方能繼(ji)續(xu)工作，否則(ze)(ze)故(gu)障(zhang)會迅速擴大，直至燒毀電(dian)動(dong)(dong)機。

5、保持電(dian)(dian)動機溫(wen)度和溫(wen)升(sheng)在(zai)(zai)正(zheng)常范圍(wei)內。電(dian)(dian)機運行中，要(yao)(yao)隨時檢查軸(zhou)承(cheng)、定(ding)子、外(wai)殼等(deng)部位的(de)(de)溫(wen)度有無異常，特(te)別是對沒(mei)有過載保護的(de)(de)電(dian)(dian)動機，監視溫(wen)度更(geng)為(wei)重(zhong)要(yao)(yao)。如軸(zhou)承(cheng)缺油或損壞(huai)，則必(bi)然(ran)引(yin)起溫(wen)度升(sheng)高。在(zai)(zai)軸(zhou)承(cheng)附近機體溫(wen)度升(sheng)高，就要(yao)(yao)立即停機檢查軸(zhou)承(cheng)，可先加(jia)油，若(ruo)仍然(ran)無效，則應拆(chai)下(xia)軸(zhou)承(cheng)鑒定(ding)。若(ruo)滾動體、滾道表面(mian)有裂紋、劃傷或損壞(huai)，或間隙(xi)變大，內環在(zai)(zai)軸(zhou)承(cheng)上有轉動，出現(xian)任何一(yi)項，都(dou)應更(geng)換軸(zhou)承(cheng)。否(fou)則繼續使(shi)(shi)用會使(shi)(shi)軸(zhou)承(cheng)進一(yi)步損壞(huai)，導致(zhi)塌架、電(dian)(dian)機掃膛燒毀等(deng)重(zhong)大事故(gu)。監測電(dian)(dian)動機的(de)(de)溫(wen)度或溫(wen)升(sheng)有無變化，可用下(xia)述簡單方法監視：在(zai)(zai)電(dian)(dian)動機的(de)(de)孔內，插(cha)支溫(wen)度計，用棉花團塞緊固(gu)定(ding)，便可隨時監視電(dian)(dian)動機溫(wen)度的(de)(de)變化，機外(wai)與殼內溫(wen)差(cha)通常為(wei)1℃。

6、及(ji)(ji)時(shi)發(fa)現(xian)和處理(li)電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)異(yi)常，電(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)運行(xing)中應沒有(you)振動(dong)、噪聲和異(yi)味。若(ruo)出現(xian)振動(dong)，則會(hui)引起電(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)相連接的負載作機(ji)(ji)(ji)的軸(zhou)心(xin)不同(tong)心(xin)度的增大(da)，進(jin)而負荷增大(da)，負荷電(dian)(dian)(dian)(dian)流也隨之(zhi)增大(da)，導致溫度升高而燒毀電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)。因此，要經常檢查(cha)(cha)引起振動(dong)的地腳螺栓、電(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)端蓋(gai)、軸(zhou)承壓蓋(gai)等(deng)處，不得有(you)松動(dong)，連接裝置必須(xu)(xu)可靠，尤(you)其對大(da)功(gong)率的電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)，必須(xu)(xu)及(ji)(ji)時(shi)發(fa)現(xian)及(ji)(ji)時(shi)排(pai)除。噪聲和異(yi)味是電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)運行(xing)異(yi)常的重要標志，也是重大(da)事故(gu)的前(qian)兆(zhao)，必須(xu)(xu)及(ji)(ji)時(shi)發(fa)現(xian)，立(li)即查(cha)(cha)明原因加以(yi)排(pai)除，否則延誤時(shi)機(ji)(ji)(ji)，擴大(da)故(gu)障范圍，釀成燒毀電(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)的嚴重事故(gu)。