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(cha)看(kan)外觀：電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)表(biao)面(mian)油漆層(ceng)應(ying)光滑(hua)平整(zheng)(zheng)，銘(ming)牌安(an)裝端正，標志(zhi)齊全；封閉式(shi)(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)座散熱(re)筋(jin)應(ying)完(wan)整(zheng)(zheng)無損，附件齊全；⑵手(shou)動(dong)(dong)旋轉：用手(shou)轉動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)軸(zhou)(zhou)、轉動(dong)(dong)應(ying)很(hen)靈活，慣動(dong)(dong)量較好，軸(zhou)(zhou)向基本無竄(cuan)動(dong)(dong)量；⑶診聽(ting)軸(zhou)(zhou)承(cheng)(cheng)：通電(dian)(dian)(dian)(dian)(dian)運(yun)行(xing)15-25分鐘，軸(zhou)(zhou)承(cheng)(cheng)應(ying)平穩輕快，無停(ting)滯現(xian)象(xiang)。聲(sheng)音均勻和(he)(he)諧(xie)；軸(zhou)(zhou)承(cheng)(cheng)溫度(du)不(bu)高(gao)，沒有漏油、甩油現(xian)象(xiang)；運(yun)行(xing)停(ting)止后，用手(shou)摸電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)座和(he)(he)端蓋不(bu)感到發(fa)熱(re)；⑷檢查(cha)接線(xian)(xian)(xian)：打開接線(xian)(xian)(xian)盒看(kan)各相(xiang)相(xiang)線(xian)(xian)(xian)標志(zhi)是(shi)否(fou)清晰(xi)完(wan)整(zheng)(zheng)，聯絡片(pian)是(shi)否(fou)壓實壓緊，螺母是(shi)否(fou)齊全；⑸測量電(dian)(dian)(dian)(dian)(dian)阻(zu)：用額(e)定電(dian)(dian)(dian)(dian)(dian)壓500V的手(shou)動(dong)(dong)式(shi)(shi)兆(zhao)歐(ou)表(biao)，測量出線(xian)(xian)(xian)端相(xiang)線(xian)(xian)(xian)與相(xiang)線(xian)(xian)(xian)之間及線(xian)(xian)(xian)對機(ji)座之間的絕緣電(dian)(dian)(dian)(dian)(dian)阻(zu)，正常電(dian)(dian)(dian)(dian)(dian)機(ji)的絕緣電(dian)(dian)(dian)(dian)(dian)阻(zu)應(ying)大于1兆(zhao)歐(ou)。⑹測量電(dian)(dian)(dian)(dian)(dian)流(liu)。在運(yun)行(xing)中用鉗型電(dian)(dian)(dian)(dian)(dian)流(liu)表(biao)測電(dian)(dian)(dian)(dian)(dian)機(ji)空(kong)載(zai)時各相(xiang)的電(dian)(dian)(dian)(dian)(dian)流(liu)，三(san)相(xiang)電(dian)(dian)(dian)(dian)(dian)流(liu)中任何(he)一相(xiang)與三(san)相(xiang)平均值(zhi)的偏差(cha)不(bu)得大于平均值(zhi)的10%，空(kong)載(zai)電(dian)(dian)(dian)(dian)(dian)流(liu)一般為額(e)定電(dian)(dian)(dian)(dian)(dian)流(liu)的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(qi)(qi)動(dong)(dong)設(she)備(bei)(bei)技術(shu)(shu)狀(zhuang)態完好(hao)(hao)，電(dian)動(dong)(dong)機啟(qi)(qi)動(dong)(dong)設(she)備(bei)(bei)技術(shu)(shu)狀(zhuang)態的(de)(de)好(hao)(hao)壞直接(jie)(jie)關系(xi)到能否順利(li)啟(qi)(qi)動(dong)(dong)。實踐表明，絕大多(duo)數燒(shao)毀(hui)的(de)(de)電(dian)動(dong)(dong)機都是(shi)啟(qi)(qi)動(dong)(dong)不(bu)順利(li)而燒(shao)毀(hui)的(de)(de)，如啟(qi)(qi)動(dong)(dong)設(she)備(bei)(bei)技術(shu)(shu)狀(zhuang)態不(bu)良引(yin)發(fa)的(de)(de)缺相啟(qi)(qi)動(dong)(dong)；接(jie)(jie)觸(chu)(chu)(chu)器(qi)觸(chu)(chu)(chu)頭拉(la)弧、打火而導致電(dian)壓、電(dian)流大幅度(du)改(gai)變等。保持(chi)啟(qi)(qi)動(dong)(dong)設(she)備(bei)(bei)技術(shu)(shu)狀(zhuang)態良好(hao)(hao)的(de)(de)措(cuo)(cuo)施是(shi)：經(jing)常做檢查、清潔、緊固(gu)工作。若接(jie)(jie)觸(chu)(chu)(chu)器(qi)觸(chu)(chu)(chu)頭不(bu)清潔，氧(yang)化燒(shao)蝕(shi)嚴(yan)重，則會(hui)產(chan)生接(jie)(jie)觸(chu)(chu)(chu)電(dian)阻增(zeng)大，引(yin)起發(fa)熱、燒(shao)蝕(shi)觸(chu)(chu)(chu)點，從而形成缺相運(yun)行而燒(shao)毀(hui)電(dian)機繞組；接(jie)(jie)觸(chu)(chu)(chu)器(qi)吸合(he)線圈(quan)鐵芯(xin)有(you)銹(xiu)蝕(shi)和灰塵(chen)，會(hui)使吸合(he)不(bu)嚴(yan)而發(fa)出(chu)強烈噪聲，并增(zeng)大線圈(quan)電(dian)流，直至(zhi)燒(shao)毀(hui)線圈(quan)。因(yin)此，電(dian)氣控制(zhi)柜應設(she)在干燥、通風和便于(yu)操(cao)作的(de)(de)位置；還(huan)要(yao)(yao)定期除塵(chen)、清理(li)觸(chu)(chu)(chu)點；線圈(quan)鐵芯(xin)要(yao)(yao)增(zeng)加防銹(xiu)措(cuo)(cuo)施；要(yao)(yao)經(jing)常緊固(gu)各連接(jie)(jie)部件(jian)(jian)；檢查接(jie)(jie)觸(chu)(chu)(chu)器(qi)觸(chu)(chu)(chu)點，保證接(jie)(jie)觸(chu)(chu)(chu)良好(hao)(hao)，機構動(dong)(dong)作應靈活、準確(que)，這些是(shi)保證啟(qi)(qi)動(dong)(dong)順利(li)的(de)(de)必然(ran)條(tiao)件(jian)(jian)。

2、保(bao)持(chi)電動機(ji)(ji)清(qing)(qing)潔和良好的(de)冷(leng)(leng)卻環境，在電動機(ji)(ji)的(de)進風口處，必須經常保(bao)持(chi)清(qing)(qing)潔。進風口的(de)周圍不得(de)有塵土、油污(wu)、水漬和其它秸稈雜物，以防止(zhi)這類東西吸入(ru)電機(ji)(ji)內部，形成(cheng)短路介質或損(sun)傷電機(ji)(ji)繞組(zu)絕緣層(ceng)；或阻斷電機(ji)(ji)的(de)通風冷(leng)(leng)卻而(er)溫度升高，導致燒毀。

3、保持電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)在額定電(dian)(dian)(dian)流(liu)下(xia)工(gong)作，避免農用電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)的(de)(de)過(guo)載(zai)運行。當電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)處于過(guo)載(zai)狀態運行時(shi)，電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)轉速下(xia)降，電(dian)(dian)(dian)流(liu)增(zeng)大，溫度(du)升高，繞組線(xian)圈過(guo)熱(re)。其主(zhu)要原因(yin)是(shi)拖(tuo)(tuo)動(dong)負荷過(guo)大，電(dian)(dian)(dian)壓過(guo)低或(huo)被(bei)拖(tuo)(tuo)動(dong)的(de)(de)機(ji)(ji)(ji)械卡滯等造成的(de)(de)；若過(guo)載(zai)時(shi)間(jian)稍長(chang)，過(guo)載(zai)電(dian)(dian)(dian)機(ji)(ji)(ji)從電(dian)(dian)(dian)網中吸收大量有功功率，電(dian)(dian)(dian)流(liu)便(bian)急(ji)劇(ju)增(zeng)加(jia)，隨之溫度(du)上升。在高溫下(xia)運行的(de)(de)電(dian)(dian)(dian)機(ji)(ji)(ji)，絕緣材料易老化失效而燒毀繞組線(xian)圈，這是(shi)燒毀電(dian)(dian)(dian)機(ji)(ji)(ji)的(de)(de)主(zhu)要原因(yin)。因(yin)此，一要經常注意檢(jian)查機(ji)(ji)(ji)組傳動(dong)裝(zhuang)置是(shi)否(fou)運轉靈活、可靠，隨時(shi)檢(jian)查、調整傳動(dong)皮帶松(song)緊度(du)，防止卡滯；二要注意作業機(ji)(ji)(ji)械不(bu)要較(jiao)長(chang)時(shi)間(jian)超負荷工(gong)作；三要保持電(dian)(dian)(dian)壓穩定，尤其不(bu)得低壓運轉，從而確保電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)在額定電(dian)(dian)(dian)流(liu)下(xia)正常工(gong)作。

4、保持(chi)相間電(dian)(dian)流(liu)平衡。農(nong)用三相異步電(dian)(dian)動(dong)機(ji)，其(qi)中任何一(yi)相的電(dian)(dian)流(liu)值與其(qi)他兩相電(dian)(dian)流(liu)平均值之(zhi)差不得(de)超(chao)過10%，這是保證電(dian)(dian)動(dong)機(ji)安(an)全(quan)運轉的必要(yao)條件。如(ru)果這個差值超(chao)過10%，則表(biao)明電(dian)(dian)動(dong)機(ji)已經出現故障，必須立即(ji)停機(ji)查明原因，并排除故障后方能繼(ji)續工(gong)作(zuo)，否(fou)則故障會迅速擴大，直至燒毀電(dian)(dian)動(dong)機(ji)。

5、保(bao)(bao)持電(dian)動機(ji)(ji)溫(wen)(wen)度(du)(du)(du)和溫(wen)(wen)升在(zai)(zai)正常范圍(wei)內(nei)。電(dian)機(ji)(ji)運行中，要(yao)隨(sui)時(shi)檢(jian)查(cha)(cha)軸(zhou)(zhou)(zhou)承(cheng)、定子、外殼(ke)等(deng)部位的(de)(de)溫(wen)(wen)度(du)(du)(du)有(you)(you)(you)無(wu)異常，特別是(shi)對沒有(you)(you)(you)過載保(bao)(bao)護的(de)(de)電(dian)動機(ji)(ji)，監(jian)視(shi)溫(wen)(wen)度(du)(du)(du)更為重要(yao)。如軸(zhou)(zhou)(zhou)承(cheng)缺油(you)或損(sun)(sun)壞，則(ze)必然引(yin)起溫(wen)(wen)度(du)(du)(du)升高。在(zai)(zai)軸(zhou)(zhou)(zhou)承(cheng)附近機(ji)(ji)體(ti)溫(wen)(wen)度(du)(du)(du)升高，就(jiu)要(yao)立即停機(ji)(ji)檢(jian)查(cha)(cha)軸(zhou)(zhou)(zhou)承(cheng)，可先加(jia)油(you)，若仍然無(wu)效，則(ze)應(ying)拆下軸(zhou)(zhou)(zhou)承(cheng)鑒定。若滾動體(ti)、滾道(dao)表面有(you)(you)(you)裂紋、劃傷或損(sun)(sun)壞，或間隙變(bian)大(da)，內(nei)環在(zai)(zai)軸(zhou)(zhou)(zhou)承(cheng)上有(you)(you)(you)轉動，出現(xian)任何一項，都(dou)應(ying)更換軸(zhou)(zhou)(zhou)承(cheng)。否(fou)則(ze)繼續使用(yong)會使軸(zhou)(zhou)(zhou)承(cheng)進(jin)一步損(sun)(sun)壞，導致塌架(jia)、電(dian)機(ji)(ji)掃膛燒毀等(deng)重大(da)事故(gu)。監(jian)測電(dian)動機(ji)(ji)的(de)(de)溫(wen)(wen)度(du)(du)(du)或溫(wen)(wen)升有(you)(you)(you)無(wu)變(bian)化(hua)，可用(yong)下述簡(jian)單(dan)方法監(jian)視(shi)：在(zai)(zai)電(dian)動機(ji)(ji)的(de)(de)孔內(nei)，插支溫(wen)(wen)度(du)(du)(du)計，用(yong)棉花(hua)團塞緊固定，便可隨(sui)時(shi)監(jian)視(shi)電(dian)動機(ji)(ji)溫(wen)(wen)度(du)(du)(du)的(de)(de)變(bian)化(hua)，機(ji)(ji)外與殼(ke)內(nei)溫(wen)(wen)差通常為1℃。

6、及(ji)時(shi)發(fa)現和處理電(dian)(dian)(dian)機(ji)(ji)異常，電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)運(yun)行中應沒有振動(dong)(dong)、噪聲(sheng)和異味。若出(chu)現振動(dong)(dong)，則(ze)會引起(qi)電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)相連(lian)接(jie)的(de)(de)(de)(de)負(fu)載作機(ji)(ji)的(de)(de)(de)(de)軸(zhou)心不同心度的(de)(de)(de)(de)增(zeng)大(da)(da)，進而負(fu)荷增(zeng)大(da)(da)，負(fu)荷電(dian)(dian)(dian)流也(ye)隨之增(zeng)大(da)(da)，導致溫度升高而燒毀電(dian)(dian)(dian)機(ji)(ji)。因(yin)此，要(yao)經常檢查引起(qi)振動(dong)(dong)的(de)(de)(de)(de)地腳螺栓、電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)端蓋(gai)、軸(zhou)承壓蓋(gai)等處，不得有松動(dong)(dong)，連(lian)接(jie)裝(zhuang)置必(bi)須(xu)可靠(kao)，尤其對大(da)(da)功(gong)率的(de)(de)(de)(de)電(dian)(dian)(dian)機(ji)(ji)，必(bi)須(xu)及(ji)時(shi)發(fa)現及(ji)時(shi)排除(chu)。噪聲(sheng)和異味是電(dian)(dian)(dian)機(ji)(ji)運(yun)行異常的(de)(de)(de)(de)重(zhong)要(yao)標志，也(ye)是重(zhong)大(da)(da)事故的(de)(de)(de)(de)前兆，必(bi)須(xu)及(ji)時(shi)發(fa)現，立即(ji)查明(ming)原因(yin)加以排除(chu)，否則(ze)延誤時(shi)機(ji)(ji)，擴大(da)(da)故障范(fan)圍，釀成(cheng)燒毀電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)的(de)(de)(de)(de)嚴重(zhong)事故。