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(kan)外觀：電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)(ji)表(biao)面油(you)漆層應(ying)(ying)光滑平(ping)(ping)整，銘(ming)牌安裝端正，標志齊全；封閉式電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)(ji)座(zuo)(zuo)散熱(re)(re)筋(jin)應(ying)(ying)完整無損，附(fu)件齊全；⑵手(shou)動(dong)(dong)旋轉(zhuan)：用手(shou)轉(zhuan)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)軸(zhou)(zhou)(zhou)(zhou)、轉(zhuan)動(dong)(dong)應(ying)(ying)很靈活，慣動(dong)(dong)量(liang)(liang)較好，軸(zhou)(zhou)(zhou)(zhou)向基本(ben)無竄(cuan)動(dong)(dong)量(liang)(liang)；⑶診聽軸(zhou)(zhou)(zhou)(zhou)承：通電(dian)(dian)(dian)(dian)(dian)(dian)運行15-25分鐘(zhong)，軸(zhou)(zhou)(zhou)(zhou)承應(ying)(ying)平(ping)(ping)穩輕快，無停滯現(xian)(xian)象。聲音均(jun)勻和諧；軸(zhou)(zhou)(zhou)(zhou)承溫度不高，沒有漏油(you)、甩油(you)現(xian)(xian)象；運行停止后，用手(shou)摸電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)(ji)(ji)座(zuo)(zuo)和端蓋不感到發熱(re)(re)；⑷檢(jian)查接線：打開(kai)接線盒看(kan)各相(xiang)(xiang)相(xiang)(xiang)線標志是(shi)否(fou)清晰完整，聯絡(luo)片是(shi)否(fou)壓實(shi)壓緊，螺(luo)母是(shi)否(fou)齊全；⑸測量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)：用額定電(dian)(dian)(dian)(dian)(dian)(dian)壓500V的(de)(de)手(shou)動(dong)(dong)式兆(zhao)歐表(biao)，測量(liang)(liang)出線端相(xiang)(xiang)線與(yu)(yu)相(xiang)(xiang)線之間及線對機(ji)(ji)(ji)(ji)(ji)座(zuo)(zuo)之間的(de)(de)絕緣電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)，正常電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)(ji)的(de)(de)絕緣電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)應(ying)(ying)大(da)于(yu)1兆(zhao)歐。⑹測量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)流。在(zai)運行中(zhong)用鉗型(xing)電(dian)(dian)(dian)(dian)(dian)(dian)流表(biao)測電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)(ji)空載時各相(xiang)(xiang)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流，三相(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)流中(zhong)任何一相(xiang)(xiang)與(yu)(yu)三相(xiang)(xiang)平(ping)(ping)均(jun)值的(de)(de)偏差不得大(da)于(yu)平(ping)(ping)均(jun)值的(de)(de)10%，空載電(dian)(dian)(dian)(dian)(dian)(dian)流一般(ban)為額定電(dian)(dian)(dian)(dian)(dian)(dian)流的(de)(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、保持(chi)啟動設(she)備(bei)(bei)技(ji)(ji)術(shu)(shu)狀(zhuang)態(tai)(tai)完好，電動機(ji)啟動設(she)備(bei)(bei)技(ji)(ji)術(shu)(shu)狀(zhuang)態(tai)(tai)的(de)好壞(huai)直接關系到能否(fou)順(shun)(shun)利啟動。實踐表明，絕大(da)多數燒毀(hui)的(de)電動機(ji)都是(shi)(shi)啟動不順(shun)(shun)利而燒毀(hui)的(de)，如(ru)啟動設(she)備(bei)(bei)技(ji)(ji)術(shu)(shu)狀(zhuang)態(tai)(tai)不良引發的(de)缺相(xiang)啟動；接觸(chu)器觸(chu)頭(tou)(tou)拉(la)弧、打火而導致電壓、電流(liu)大(da)幅(fu)度改變等。保持(chi)啟動設(she)備(bei)(bei)技(ji)(ji)術(shu)(shu)狀(zhuang)態(tai)(tai)良好的(de)措施(shi)是(shi)(shi)：經常做檢(jian)查、清潔(jie)、緊固(gu)工作。若接觸(chu)器觸(chu)頭(tou)(tou)不清潔(jie)，氧(yang)化(hua)燒蝕(shi)嚴(yan)重，則會產生接觸(chu)電阻增大(da)，引起發熱、燒蝕(shi)觸(chu)點，從而形成缺相(xiang)運行(xing)而燒毀(hui)電機(ji)繞組(zu)；接觸(chu)器吸合(he)線(xian)圈鐵(tie)芯(xin)(xin)有銹(xiu)蝕(shi)和灰塵，會使(shi)吸合(he)不嚴(yan)而發出強烈(lie)噪聲，并增大(da)線(xian)圈電流(liu)，直至燒毀(hui)線(xian)圈。因此(ci)，電氣(qi)控制柜應設(she)在干燥、通風(feng)和便于操作的(de)位置(zhi)；還要(yao)定(ding)期(qi)除(chu)塵、清理觸(chu)點；線(xian)圈鐵(tie)芯(xin)(xin)要(yao)增加(jia)防銹(xiu)措施(shi)；要(yao)經常緊固(gu)各連接部(bu)件；檢(jian)查接觸(chu)器觸(chu)點，保證接觸(chu)良好，機(ji)構動作應靈活、準確，這些(xie)是(shi)(shi)保證啟動順(shun)(shun)利的(de)必然(ran)條件。

2、保持(chi)電(dian)動機清(qing)(qing)潔(jie)和(he)良好的冷(leng)卻(que)環境，在電(dian)動機的進風口(kou)處，必須經常保持(chi)清(qing)(qing)潔(jie)。進風口(kou)的周圍(wei)不得有塵(chen)土、油污、水漬和(he)其(qi)它(ta)秸稈雜(za)物(wu)，以防(fang)止(zhi)這類東(dong)西吸入(ru)電(dian)機內(nei)部(bu)，形成短(duan)路介質(zhi)或損(sun)傷電(dian)機繞組(zu)絕(jue)緣層；或阻斷電(dian)機的通風冷(leng)卻(que)而溫度升(sheng)高，導致燒毀。

3、保(bao)持(chi)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)在額定電(dian)(dian)流下工作(zuo)，避免(mian)農用(yong)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)的(de)過載運行。當電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)處于(yu)過載狀態(tai)運行時，電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)轉(zhuan)(zhuan)速下降，電(dian)(dian)流增(zeng)大，溫(wen)度升高，繞(rao)組線圈過熱。其(qi)主要(yao)(yao)原(yuan)因是拖動(dong)(dong)(dong)負荷過大，電(dian)(dian)壓(ya)過低(di)或被拖動(dong)(dong)(dong)的(de)機(ji)(ji)(ji)(ji)械卡滯等(deng)造成的(de)；若過載時間稍長(chang)，過載電(dian)(dian)機(ji)(ji)(ji)(ji)從(cong)電(dian)(dian)網(wang)中吸收(shou)大量有功(gong)功(gong)率，電(dian)(dian)流便急(ji)劇增(zeng)加，隨之溫(wen)度上升。在高溫(wen)下運行的(de)電(dian)(dian)機(ji)(ji)(ji)(ji)，絕緣材料易(yi)老化失(shi)效(xiao)而燒毀(hui)繞(rao)組線圈，這是燒毀(hui)電(dian)(dian)機(ji)(ji)(ji)(ji)的(de)主要(yao)(yao)原(yuan)因。因此，一要(yao)(yao)經常注(zhu)(zhu)意檢查機(ji)(ji)(ji)(ji)組傳動(dong)(dong)(dong)裝置(zhi)是否(fou)運轉(zhuan)(zhuan)靈活、可靠，隨時檢查、調整傳動(dong)(dong)(dong)皮帶松(song)緊度，防止卡滯；二要(yao)(yao)注(zhu)(zhu)意作(zuo)業機(ji)(ji)(ji)(ji)械不要(yao)(yao)較(jiao)長(chang)時間超負荷工作(zuo)；三要(yao)(yao)保(bao)持(chi)電(dian)(dian)壓(ya)穩(wen)定，尤其(qi)不得低(di)壓(ya)運轉(zhuan)(zhuan)，從(cong)而確保(bao)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)在額定電(dian)(dian)流下正常工作(zuo)。

4、保持相(xiang)(xiang)間電(dian)流平衡。農用(yong)三相(xiang)(xiang)異步電(dian)動(dong)(dong)機(ji)，其中(zhong)任(ren)何一相(xiang)(xiang)的電(dian)流值(zhi)與(yu)其他兩相(xiang)(xiang)電(dian)流平均值(zhi)之差不(bu)得超(chao)過10%，這是(shi)保證電(dian)動(dong)(dong)機(ji)安(an)全運轉的必要條件(jian)。如果這個差值(zhi)超(chao)過10%，則表(biao)明電(dian)動(dong)(dong)機(ji)已(yi)經出現(xian)故(gu)障(zhang)，必須立即停機(ji)查(cha)明原因，并排除故(gu)障(zhang)后方能繼續工作，否則故(gu)障(zhang)會迅速擴(kuo)大，直至燒毀電(dian)動(dong)(dong)機(ji)。

5、保持電(dian)動機溫(wen)(wen)(wen)(wen)度(du)和溫(wen)(wen)(wen)(wen)升(sheng)在(zai)(zai)正常(chang)范圍內(nei)。電(dian)機運行中，要隨時檢查軸(zhou)承(cheng)、定(ding)子、外(wai)殼等(deng)部位(wei)的(de)溫(wen)(wen)(wen)(wen)度(du)有(you)無(wu)異常(chang)，特別(bie)是對(dui)沒(mei)有(you)過(guo)載保護的(de)電(dian)動機，監(jian)(jian)視溫(wen)(wen)(wen)(wen)度(du)更為重要。如軸(zhou)承(cheng)缺油或損壞(huai)(huai)(huai)，則必然引起(qi)溫(wen)(wen)(wen)(wen)度(du)升(sheng)高。在(zai)(zai)軸(zhou)承(cheng)附近(jin)機體(ti)溫(wen)(wen)(wen)(wen)度(du)升(sheng)高，就要立即停(ting)機檢查軸(zhou)承(cheng)，可先(xian)加(jia)油，若(ruo)仍然無(wu)效，則應拆(chai)下軸(zhou)承(cheng)鑒(jian)定(ding)。若(ruo)滾動體(ti)、滾道表(biao)面有(you)裂紋、劃傷或損壞(huai)(huai)(huai)，或間隙變大(da)，內(nei)環在(zai)(zai)軸(zhou)承(cheng)上有(you)轉動，出現任(ren)何一項，都(dou)應更換軸(zhou)承(cheng)。否則繼續使(shi)用(yong)(yong)會使(shi)軸(zhou)承(cheng)進一步損壞(huai)(huai)(huai)，導致(zhi)塌架、電(dian)機掃膛(tang)燒(shao)毀等(deng)重大(da)事故(gu)。監(jian)(jian)測電(dian)動機的(de)溫(wen)(wen)(wen)(wen)度(du)或溫(wen)(wen)(wen)(wen)升(sheng)有(you)無(wu)變化(hua)，可用(yong)(yong)下述簡單方法監(jian)(jian)視：在(zai)(zai)電(dian)動機的(de)孔內(nei)，插(cha)支溫(wen)(wen)(wen)(wen)度(du)計，用(yong)(yong)棉花團塞緊(jin)固(gu)定(ding)，便可隨時監(jian)(jian)視電(dian)動機溫(wen)(wen)(wen)(wen)度(du)的(de)變化(hua)，機外(wai)與殼內(nei)溫(wen)(wen)(wen)(wen)差通常(chang)為1℃。

6、及(ji)時(shi)(shi)發(fa)(fa)現(xian)和(he)處(chu)理電(dian)機(ji)異(yi)常(chang)(chang)，電(dian)動(dong)機(ji)運(yun)(yun)行(xing)中應沒有振動(dong)、噪聲(sheng)和(he)異(yi)味。若(ruo)出現(xian)振動(dong)，則會(hui)引(yin)起(qi)電(dian)動(dong)機(ji)相連接的(de)負載作(zuo)機(ji)的(de)軸(zhou)心不同心度的(de)增(zeng)大(da)(da)，進而(er)負荷(he)增(zeng)大(da)(da)，負荷(he)電(dian)流也(ye)隨之增(zeng)大(da)(da)，導致溫度升高(gao)而(er)燒(shao)毀電(dian)機(ji)。因此，要經常(chang)(chang)檢(jian)查(cha)引(yin)起(qi)振動(dong)的(de)地腳螺栓(shuan)、電(dian)動(dong)機(ji)端蓋(gai)、軸(zhou)承壓(ya)蓋(gai)等(deng)處(chu)，不得有松(song)動(dong)，連接裝置必(bi)須(xu)可靠(kao)，尤其對大(da)(da)功(gong)率的(de)電(dian)機(ji)，必(bi)須(xu)及(ji)時(shi)(shi)發(fa)(fa)現(xian)及(ji)時(shi)(shi)排除。噪聲(sheng)和(he)異(yi)味是電(dian)機(ji)運(yun)(yun)行(xing)異(yi)常(chang)(chang)的(de)重要標志，也(ye)是重大(da)(da)事故的(de)前兆，必(bi)須(xu)及(ji)時(shi)(shi)發(fa)(fa)現(xian)，立即查(cha)明(ming)原因加以排除，否則延誤時(shi)(shi)機(ji)，擴大(da)(da)故障范圍，釀成燒(shao)毀電(dian)動(dong)機(ji)的(de)嚴(yan)重事故。