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)(dian)(dian)(dian)(dian)動(dong)機(ji)表面油漆層應(ying)(ying)光滑平(ping)整(zheng)，銘牌安裝端正，標志(zhi)齊全；封閉式(shi)(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)座(zuo)(zuo)(zuo)散熱(re)筋應(ying)(ying)完整(zheng)無損，附(fu)件(jian)齊全；⑵手動(dong)旋轉：用手轉動(dong)電(dian)(dian)(dian)(dian)(dian)軸(zhou)(zhou)、轉動(dong)應(ying)(ying)很靈活，慣動(dong)量(liang)較好，軸(zhou)(zhou)向(xiang)基(ji)本無竄(cuan)動(dong)量(liang)；⑶診聽軸(zhou)(zhou)承(cheng)(cheng)：通電(dian)(dian)(dian)(dian)(dian)運(yun)行15-25分鐘，軸(zhou)(zhou)承(cheng)(cheng)應(ying)(ying)平(ping)穩輕快，無停滯(zhi)現(xian)(xian)象。聲音均(jun)(jun)勻和(he)(he)諧；軸(zhou)(zhou)承(cheng)(cheng)溫度不(bu)(bu)高，沒有漏油、甩(shuai)油現(xian)(xian)象；運(yun)行停止后，用手摸電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)座(zuo)(zuo)(zuo)和(he)(he)端蓋(gai)不(bu)(bu)感到發熱(re)；⑷檢查接線(xian)：打開(kai)接線(xian)盒(he)看各(ge)相(xiang)相(xiang)線(xian)標志(zhi)是否(fou)清晰完整(zheng)，聯絡(luo)片是否(fou)壓實壓緊，螺母是否(fou)齊全；⑸測量(liang)電(dian)(dian)(dian)(dian)(dian)阻：用額(e)定電(dian)(dian)(dian)(dian)(dian)壓500V的(de)(de)手動(dong)式(shi)(shi)兆(zhao)歐表，測量(liang)出(chu)線(xian)端相(xiang)線(xian)與相(xiang)線(xian)之間(jian)及線(xian)對機(ji)座(zuo)(zuo)(zuo)之間(jian)的(de)(de)絕緣(yuan)電(dian)(dian)(dian)(dian)(dian)阻，正常(chang)電(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)絕緣(yuan)電(dian)(dian)(dian)(dian)(dian)阻應(ying)(ying)大(da)(da)于1兆(zhao)歐。⑹測量(liang)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。在(zai)運(yun)行中用鉗型電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)表測電(dian)(dian)(dian)(dian)(dian)機(ji)空載(zai)(zai)時各(ge)相(xiang)的(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)，三(san)相(xiang)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)中任何一相(xiang)與三(san)相(xiang)平(ping)均(jun)(jun)值(zhi)的(de)(de)偏差(cha)不(bu)(bu)得(de)大(da)(da)于平(ping)均(jun)(jun)值(zhi)的(de)(de)10%，空載(zai)(zai)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)一般為額(e)定電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)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(bao)(bao)持啟(qi)(qi)動(dong)(dong)(dong)(dong)設備技(ji)術(shu)(shu)狀(zhuang)態(tai)完好(hao)，電(dian)(dian)動(dong)(dong)(dong)(dong)機啟(qi)(qi)動(dong)(dong)(dong)(dong)設備技(ji)術(shu)(shu)狀(zhuang)態(tai)的(de)好(hao)壞(huai)直(zhi)接(jie)(jie)關系到(dao)能否(fou)順利(li)啟(qi)(qi)動(dong)(dong)(dong)(dong)。實踐表明，絕大多(duo)數(shu)燒(shao)毀的(de)電(dian)(dian)動(dong)(dong)(dong)(dong)機都是(shi)啟(qi)(qi)動(dong)(dong)(dong)(dong)不順利(li)而燒(shao)毀的(de)，如啟(qi)(qi)動(dong)(dong)(dong)(dong)設備技(ji)術(shu)(shu)狀(zhuang)態(tai)不良引發的(de)缺相(xiang)啟(qi)(qi)動(dong)(dong)(dong)(dong)；接(jie)(jie)觸器觸頭拉弧、打(da)火而導致電(dian)(dian)壓、電(dian)(dian)流大幅度改變等。保(bao)(bao)持啟(qi)(qi)動(dong)(dong)(dong)(dong)設備技(ji)術(shu)(shu)狀(zhuang)態(tai)良好(hao)的(de)措施(shi)是(shi)：經常做檢(jian)查、清潔(jie)、緊固工作。若(ruo)接(jie)(jie)觸器觸頭不清潔(jie)，氧(yang)化燒(shao)蝕嚴(yan)重，則會產生接(jie)(jie)觸電(dian)(dian)阻(zu)增大，引起發熱(re)、燒(shao)蝕觸點，從而形成缺相(xiang)運行(xing)而燒(shao)毀電(dian)(dian)機繞組；接(jie)(jie)觸器吸合(he)線(xian)圈鐵(tie)芯有(you)銹(xiu)蝕和灰塵(chen)，會使吸合(he)不嚴(yan)而發出強烈噪聲，并增大線(xian)圈電(dian)(dian)流，直(zhi)至燒(shao)毀線(xian)圈。因此，電(dian)(dian)氣控制(zhi)柜應設在(zai)干燥、通風和便于操作的(de)位置(zhi)；還(huan)要定期除塵(chen)、清理(li)觸點；線(xian)圈鐵(tie)芯要增加防銹(xiu)措施(shi)；要經常緊固各(ge)連接(jie)(jie)部件；檢(jian)查接(jie)(jie)觸器觸點，保(bao)(bao)證接(jie)(jie)觸良好(hao)，機構動(dong)(dong)(dong)(dong)作應靈活(huo)、準確，這些(xie)是(shi)保(bao)(bao)證啟(qi)(qi)動(dong)(dong)(dong)(dong)順利(li)的(de)必然條件。

2、保(bao)持(chi)(chi)電(dian)(dian)動機(ji)清(qing)潔(jie)和(he)(he)良好的(de)(de)冷(leng)卻(que)(que)環境，在電(dian)(dian)動機(ji)的(de)(de)進風(feng)(feng)口處，必須(xu)經常保(bao)持(chi)(chi)清(qing)潔(jie)。進風(feng)(feng)口的(de)(de)周圍不(bu)得有(you)塵土、油(you)污、水漬和(he)(he)其它秸(jie)稈雜物(wu)，以(yi)防止(zhi)這(zhe)類東西吸入電(dian)(dian)機(ji)內部，形成(cheng)短路介質或損(sun)傷(shang)電(dian)(dian)機(ji)繞組絕緣層；或阻斷(duan)電(dian)(dian)機(ji)的(de)(de)通風(feng)(feng)冷(leng)卻(que)(que)而(er)溫度升高，導致燒毀。

3、保持(chi)電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)在(zai)額(e)定(ding)(ding)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)下(xia)工作(zuo)，避免農用電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)的(de)(de)過(guo)載(zai)運(yun)(yun)行(xing)(xing)。當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)處于過(guo)載(zai)狀態(tai)運(yun)(yun)行(xing)(xing)時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)轉(zhuan)速下(xia)降(jiang)，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)增大，溫(wen)度(du)升高，繞組(zu)線圈過(guo)熱。其(qi)主要(yao)(yao)原因(yin)是拖動(dong)(dong)(dong)負荷過(guo)大，電(dian)(dian)(dian)(dian)(dian)(dian)壓過(guo)低(di)或被(bei)拖動(dong)(dong)(dong)的(de)(de)機(ji)(ji)(ji)(ji)械(xie)卡滯(zhi)等造成(cheng)的(de)(de)；若(ruo)過(guo)載(zai)時(shi)間(jian)稍長，過(guo)載(zai)電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)從(cong)(cong)電(dian)(dian)(dian)(dian)(dian)(dian)網中吸收大量有功(gong)功(gong)率，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)便急劇增加，隨(sui)之溫(wen)度(du)上升。在(zai)高溫(wen)下(xia)運(yun)(yun)行(xing)(xing)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)，絕緣材料易(yi)老化(hua)失效而(er)燒(shao)毀(hui)繞組(zu)線圈，這是燒(shao)毀(hui)電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)的(de)(de)主要(yao)(yao)原因(yin)。因(yin)此，一要(yao)(yao)經常注意檢(jian)查機(ji)(ji)(ji)(ji)組(zu)傳(chuan)動(dong)(dong)(dong)裝置是否運(yun)(yun)轉(zhuan)靈(ling)活、可靠(kao)，隨(sui)時(shi)檢(jian)查、調整傳(chuan)動(dong)(dong)(dong)皮帶松緊度(du)，防止卡滯(zhi)；二要(yao)(yao)注意作(zuo)業機(ji)(ji)(ji)(ji)械(xie)不要(yao)(yao)較長時(shi)間(jian)超(chao)負荷工作(zuo)；三要(yao)(yao)保持(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓穩(wen)定(ding)(ding)，尤(you)其(qi)不得低(di)壓運(yun)(yun)轉(zhuan)，從(cong)(cong)而(er)確保電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)在(zai)額(e)定(ding)(ding)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)下(xia)正常工作(zuo)。

4、保(bao)持相(xiang)間電(dian)流平衡。農用(yong)三相(xiang)異步電(dian)動(dong)機(ji)，其中任(ren)何一相(xiang)的(de)電(dian)流值與其他兩相(xiang)電(dian)流平均(jun)值之(zhi)差不得超(chao)過(guo)(guo)10%，這(zhe)是保(bao)證電(dian)動(dong)機(ji)安全運轉的(de)必要(yao)條(tiao)件。如果這(zhe)個差值超(chao)過(guo)(guo)10%，則表明(ming)電(dian)動(dong)機(ji)已經出現故障(zhang)(zhang)，必須立即停(ting)機(ji)查明(ming)原因，并排除故障(zhang)(zhang)后(hou)方能繼續工作(zuo)，否(fou)則故障(zhang)(zhang)會迅速擴(kuo)大，直至(zhi)燒(shao)毀(hui)電(dian)動(dong)機(ji)。

5、保持電動機(ji)(ji)溫(wen)(wen)(wen)度(du)(du)和溫(wen)(wen)(wen)升(sheng)(sheng)(sheng)在(zai)(zai)正常范圍內(nei)。電機(ji)(ji)運行中，要隨(sui)時(shi)檢(jian)查(cha)(cha)軸(zhou)(zhou)(zhou)(zhou)(zhou)承(cheng)、定子、外殼(ke)等部(bu)位的溫(wen)(wen)(wen)度(du)(du)有(you)(you)無(wu)異常，特別是對(dui)沒有(you)(you)過載保護的電動機(ji)(ji)，監視(shi)溫(wen)(wen)(wen)度(du)(du)更為(wei)重要。如軸(zhou)(zhou)(zhou)(zhou)(zhou)承(cheng)缺油(you)或(huo)損(sun)(sun)壞，則(ze)必然引起溫(wen)(wen)(wen)度(du)(du)升(sheng)(sheng)(sheng)高。在(zai)(zai)軸(zhou)(zhou)(zhou)(zhou)(zhou)承(cheng)附近機(ji)(ji)體溫(wen)(wen)(wen)度(du)(du)升(sheng)(sheng)(sheng)高，就要立(li)即停機(ji)(ji)檢(jian)查(cha)(cha)軸(zhou)(zhou)(zhou)(zhou)(zhou)承(cheng)，可先加油(you)，若仍然無(wu)效，則(ze)應(ying)拆下(xia)軸(zhou)(zhou)(zhou)(zhou)(zhou)承(cheng)鑒定。若滾(gun)動體、滾(gun)道表(biao)面有(you)(you)裂紋、劃傷或(huo)損(sun)(sun)壞，或(huo)間(jian)隙變(bian)大，內(nei)環(huan)在(zai)(zai)軸(zhou)(zhou)(zhou)(zhou)(zhou)承(cheng)上(shang)有(you)(you)轉動，出現任何一項，都應(ying)更換軸(zhou)(zhou)(zhou)(zhou)(zhou)承(cheng)。否則(ze)繼(ji)續(xu)使用會(hui)使軸(zhou)(zhou)(zhou)(zhou)(zhou)承(cheng)進一步損(sun)(sun)壞，導致塌架(jia)、電機(ji)(ji)掃膛(tang)燒毀等重大事(shi)故(gu)。監測(ce)電動機(ji)(ji)的溫(wen)(wen)(wen)度(du)(du)或(huo)溫(wen)(wen)(wen)升(sheng)(sheng)(sheng)有(you)(you)無(wu)變(bian)化，可用下(xia)述簡單方法(fa)監視(shi)：在(zai)(zai)電動機(ji)(ji)的孔內(nei)，插支溫(wen)(wen)(wen)度(du)(du)計(ji)，用棉花團(tuan)塞緊固(gu)定，便可隨(sui)時(shi)監視(shi)電動機(ji)(ji)溫(wen)(wen)(wen)度(du)(du)的變(bian)化，機(ji)(ji)外與殼(ke)內(nei)溫(wen)(wen)(wen)差通常為(wei)1℃。

6、及(ji)時發(fa)現(xian)和處(chu)理電(dian)機(ji)(ji)(ji)異常，電(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)運(yun)(yun)行(xing)中應沒有振動(dong)(dong)(dong)、噪(zao)聲(sheng)和異味。若出現(xian)振動(dong)(dong)(dong)，則(ze)(ze)會引起電(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)相連接(jie)的負(fu)載作機(ji)(ji)(ji)的軸(zhou)心不同心度的增(zeng)大(da)，進而(er)(er)負(fu)荷增(zeng)大(da)，負(fu)荷電(dian)流也隨之增(zeng)大(da)，導致(zhi)溫度升高而(er)(er)燒毀電(dian)機(ji)(ji)(ji)。因此，要經(jing)常檢查(cha)引起振動(dong)(dong)(dong)的地(di)腳螺栓、電(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)端蓋、軸(zhou)承壓蓋等處(chu)，不得(de)有松動(dong)(dong)(dong)，連接(jie)裝置(zhi)必(bi)(bi)須(xu)可(ke)靠，尤(you)其(qi)對(dui)大(da)功率(lv)的電(dian)機(ji)(ji)(ji)，必(bi)(bi)須(xu)及(ji)時發(fa)現(xian)及(ji)時排(pai)除。噪(zao)聲(sheng)和異味是電(dian)機(ji)(ji)(ji)運(yun)(yun)行(xing)異常的重要標志，也是重大(da)事故(gu)(gu)的前兆，必(bi)(bi)須(xu)及(ji)時發(fa)現(xian)，立即查(cha)明原因加以排(pai)除，否則(ze)(ze)延誤時機(ji)(ji)(ji)，擴(kuo)大(da)故(gu)(gu)障范圍，釀成燒毀電(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)的嚴重事故(gu)(gu)。