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)看外(wai)觀：電(dian)(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)表(biao)面油漆(qi)層(ceng)應(ying)光滑(hua)平(ping)整，銘牌安裝端(duan)正，標志齊全(quan)；封閉式電(dian)(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)座(zuo)(zuo)散熱筋應(ying)完整無損，附(fu)件齊全(quan)；⑵手(shou)(shou)動(dong)(dong)(dong)(dong)(dong)(dong)旋轉(zhuan)：用手(shou)(shou)轉(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)電(dian)(dian)(dian)軸(zhou)、轉(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)應(ying)很靈活，慣動(dong)(dong)(dong)(dong)(dong)(dong)量(liang)(liang)較(jiao)好(hao)，軸(zhou)向(xiang)基本無竄(cuan)動(dong)(dong)(dong)(dong)(dong)(dong)量(liang)(liang)；⑶診聽軸(zhou)承：通電(dian)(dian)(dian)運(yun)行(xing)15-25分鐘，軸(zhou)承應(ying)平(ping)穩輕快，無停滯現(xian)象。聲(sheng)音均(jun)勻和諧；軸(zhou)承溫度不高(gao)，沒有漏(lou)油、甩(shuai)油現(xian)象；運(yun)行(xing)停止后(hou)，用手(shou)(shou)摸電(dian)(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)座(zuo)(zuo)和端(duan)蓋不感到發熱；⑷檢(jian)查(cha)接線(xian)：打開(kai)接線(xian)盒看各相(xiang)(xiang)相(xiang)(xiang)線(xian)標志是否(fou)清晰完整，聯絡片是否(fou)壓(ya)實壓(ya)緊(jin)，螺母是否(fou)齊全(quan)；⑸測量(liang)(liang)電(dian)(dian)(dian)阻(zu)：用額定電(dian)(dian)(dian)壓(ya)500V的(de)(de)手(shou)(shou)動(dong)(dong)(dong)(dong)(dong)(dong)式兆(zhao)歐表(biao)，測量(liang)(liang)出線(xian)端(duan)相(xiang)(xiang)線(xian)與相(xiang)(xiang)線(xian)之(zhi)間(jian)及線(xian)對機(ji)座(zuo)(zuo)之(zhi)間(jian)的(de)(de)絕緣(yuan)電(dian)(dian)(dian)阻(zu)，正常電(dian)(dian)(dian)機(ji)的(de)(de)絕緣(yuan)電(dian)(dian)(dian)阻(zu)應(ying)大于1兆(zhao)歐。⑹測量(liang)(liang)電(dian)(dian)(dian)流(liu)。在(zai)運(yun)行(xing)中(zhong)用鉗型電(dian)(dian)(dian)流(liu)表(biao)測電(dian)(dian)(dian)機(ji)空(kong)載時各相(xiang)(xiang)的(de)(de)電(dian)(dian)(dian)流(liu)，三相(xiang)(xiang)電(dian)(dian)(dian)流(liu)中(zhong)任何(he)一相(xiang)(xiang)與三相(xiang)(xiang)平(ping)均(jun)值的(de)(de)偏差(cha)不得大于平(ping)均(jun)值的(de)(de)10%，空(kong)載電(dian)(dian)(dian)流(liu)一般為額定電(dian)(dian)(dian)流(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、保持啟(qi)動(dong)(dong)(dong)(dong)(dong)(dong)設備(bei)(bei)技術(shu)狀態完好，電(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)啟(qi)動(dong)(dong)(dong)(dong)(dong)(dong)設備(bei)(bei)技術(shu)狀態的(de)好壞直接(jie)(jie)(jie)關系到能否順(shun)(shun)利(li)啟(qi)動(dong)(dong)(dong)(dong)(dong)(dong)。實踐表(biao)明，絕大多數燒毀(hui)的(de)電(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)都(dou)是(shi)啟(qi)動(dong)(dong)(dong)(dong)(dong)(dong)不順(shun)(shun)利(li)而(er)燒毀(hui)的(de)，如(ru)啟(qi)動(dong)(dong)(dong)(dong)(dong)(dong)設備(bei)(bei)技術(shu)狀態不良(liang)引(yin)發(fa)(fa)的(de)缺相啟(qi)動(dong)(dong)(dong)(dong)(dong)(dong)；接(jie)(jie)(jie)觸(chu)(chu)器觸(chu)(chu)頭拉弧、打火(huo)而(er)導致(zhi)電(dian)(dian)壓、電(dian)(dian)流大幅(fu)度(du)改變等(deng)。保持啟(qi)動(dong)(dong)(dong)(dong)(dong)(dong)設備(bei)(bei)技術(shu)狀態良(liang)好的(de)措施(shi)是(shi)：經(jing)常做檢查(cha)、清(qing)潔、緊(jin)固工作。若接(jie)(jie)(jie)觸(chu)(chu)器觸(chu)(chu)頭不清(qing)潔，氧化燒蝕(shi)嚴重，則(ze)會(hui)產生(sheng)接(jie)(jie)(jie)觸(chu)(chu)電(dian)(dian)阻增(zeng)大，引(yin)起(qi)發(fa)(fa)熱、燒蝕(shi)觸(chu)(chu)點，從而(er)形(xing)成缺相運行而(er)燒毀(hui)電(dian)(dian)機(ji)(ji)繞組；接(jie)(jie)(jie)觸(chu)(chu)器吸(xi)合(he)線(xian)圈鐵芯有銹蝕(shi)和灰塵，會(hui)使(shi)吸(xi)合(he)不嚴而(er)發(fa)(fa)出強烈噪(zao)聲，并增(zeng)大線(xian)圈電(dian)(dian)流，直至(zhi)燒毀(hui)線(xian)圈。因此，電(dian)(dian)氣控制柜應設在干燥(zao)、通風和便于操作的(de)位置；還要(yao)(yao)定期除(chu)塵、清(qing)理觸(chu)(chu)點；線(xian)圈鐵芯要(yao)(yao)增(zeng)加(jia)防銹措施(shi)；要(yao)(yao)經(jing)常緊(jin)固各連(lian)接(jie)(jie)(jie)部件(jian)；檢查(cha)接(jie)(jie)(jie)觸(chu)(chu)器觸(chu)(chu)點，保證(zheng)(zheng)接(jie)(jie)(jie)觸(chu)(chu)良(liang)好，機(ji)(ji)構動(dong)(dong)(dong)(dong)(dong)(dong)作應靈活、準(zhun)確，這些(xie)是(shi)保證(zheng)(zheng)啟(qi)動(dong)(dong)(dong)(dong)(dong)(dong)順(shun)(shun)利(li)的(de)必然條件(jian)。

2、保(bao)持電(dian)動機(ji)清潔和(he)良好的冷卻環境，在(zai)電(dian)動機(ji)的進風口處，必須經常保(bao)持清潔。進風口的周圍不得有塵土、油污、水漬和(he)其(qi)它秸稈雜物，以防止這類東西吸(xi)入(ru)電(dian)機(ji)內部，形(xing)成短路介質(zhi)或損傷電(dian)機(ji)繞組絕(jue)緣(yuan)層；或阻斷電(dian)機(ji)的通風冷卻而溫度升高，導致燒毀。

3、保持電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)在額定(ding)電(dian)(dian)流(liu)下(xia)工(gong)作，避(bi)免農用電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)的(de)過(guo)載(zai)運(yun)(yun)行(xing)。當電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)處(chu)于過(guo)載(zai)狀態(tai)運(yun)(yun)行(xing)時，電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)轉速下(xia)降，電(dian)(dian)流(liu)增大，溫(wen)(wen)度(du)升高(gao)，繞(rao)組線圈(quan)過(guo)熱(re)。其主(zhu)要(yao)原因(yin)是(shi)拖動(dong)(dong)負荷(he)過(guo)大，電(dian)(dian)壓(ya)(ya)過(guo)低或被拖動(dong)(dong)的(de)機(ji)(ji)(ji)械(xie)卡滯等造(zao)成的(de)；若過(guo)載(zai)時間稍長，過(guo)載(zai)電(dian)(dian)機(ji)(ji)(ji)從電(dian)(dian)網中吸收大量有功功率，電(dian)(dian)流(liu)便(bian)急劇(ju)增加，隨(sui)之(zhi)溫(wen)(wen)度(du)上升。在高(gao)溫(wen)(wen)下(xia)運(yun)(yun)行(xing)的(de)電(dian)(dian)機(ji)(ji)(ji)，絕緣材料(liao)易老(lao)化(hua)失效而燒毀(hui)繞(rao)組線圈(quan)，這是(shi)燒毀(hui)電(dian)(dian)機(ji)(ji)(ji)的(de)主(zhu)要(yao)原因(yin)。因(yin)此，一(yi)要(yao)經常(chang)注意(yi)檢查機(ji)(ji)(ji)組傳(chuan)動(dong)(dong)裝置是(shi)否(fou)運(yun)(yun)轉靈活、可靠，隨(sui)時檢查、調整傳(chuan)動(dong)(dong)皮帶(dai)松緊度(du)，防止卡滯；二(er)要(yao)注意(yi)作業機(ji)(ji)(ji)械(xie)不要(yao)較長時間超負荷(he)工(gong)作；三要(yao)保持電(dian)(dian)壓(ya)(ya)穩(wen)定(ding)，尤其不得低壓(ya)(ya)運(yun)(yun)轉，從而確保電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)在額定(ding)電(dian)(dian)流(liu)下(xia)正(zheng)常(chang)工(gong)作。

4、保持相(xiang)間電(dian)(dian)(dian)流平衡。農用三相(xiang)異步電(dian)(dian)(dian)動(dong)機，其(qi)中任何一(yi)相(xiang)的電(dian)(dian)(dian)流值(zhi)與其(qi)他兩相(xiang)電(dian)(dian)(dian)流平均值(zhi)之差不得(de)超過(guo)(guo)10%，這(zhe)是(shi)保證電(dian)(dian)(dian)動(dong)機安全運轉的必要條件(jian)。如果這(zhe)個差值(zhi)超過(guo)(guo)10%，則表明(ming)電(dian)(dian)(dian)動(dong)機已經出現故(gu)障，必須立(li)即停(ting)機查(cha)明(ming)原(yuan)因，并排(pai)除故(gu)障后(hou)方(fang)能(neng)繼續工作，否(fou)則故(gu)障會迅(xun)速擴(kuo)大，直至燒毀電(dian)(dian)(dian)動(dong)機。

5、保持(chi)電(dian)動機(ji)溫(wen)度(du)(du)和溫(wen)升(sheng)在(zai)正常范(fan)圍內。電(dian)機(ji)運行中，要隨時(shi)檢(jian)查(cha)(cha)軸(zhou)承(cheng)、定(ding)子(zi)、外殼(ke)等部位的溫(wen)度(du)(du)有(you)(you)無異(yi)常，特別是(shi)對(dui)沒有(you)(you)過載保護的電(dian)動機(ji)，監(jian)(jian)視溫(wen)度(du)(du)更為重要。如軸(zhou)承(cheng)缺油或(huo)損(sun)壞(huai)，則(ze)必然引(yin)起(qi)溫(wen)度(du)(du)升(sheng)高(gao)。在(zai)軸(zhou)承(cheng)附近(jin)機(ji)體溫(wen)度(du)(du)升(sheng)高(gao)，就要立即停機(ji)檢(jian)查(cha)(cha)軸(zhou)承(cheng)，可先加油，若仍然無效(xiao)，則(ze)應(ying)拆下(xia)軸(zhou)承(cheng)鑒定(ding)。若滾動體、滾道表(biao)面有(you)(you)裂紋、劃(hua)傷或(huo)損(sun)壞(huai)，或(huo)間(jian)隙變大，內環在(zai)軸(zhou)承(cheng)上(shang)有(you)(you)轉動，出(chu)現任(ren)何一(yi)項，都應(ying)更換(huan)軸(zhou)承(cheng)。否則(ze)繼續使(shi)用(yong)會使(shi)軸(zhou)承(cheng)進(jin)一(yi)步損(sun)壞(huai)，導致塌架、電(dian)機(ji)掃膛燒毀(hui)等重大事(shi)故。監(jian)(jian)測(ce)電(dian)動機(ji)的溫(wen)度(du)(du)或(huo)溫(wen)升(sheng)有(you)(you)無變化，可用(yong)下(xia)述簡單方法監(jian)(jian)視：在(zai)電(dian)動機(ji)的孔內，插(cha)支溫(wen)度(du)(du)計，用(yong)棉花團塞緊固定(ding)，便(bian)可隨時(shi)監(jian)(jian)視電(dian)動機(ji)溫(wen)度(du)(du)的變化，機(ji)外與殼(ke)內溫(wen)差(cha)通常為1℃。

6、及(ji)時(shi)發現(xian)和處(chu)理電(dian)(dian)機(ji)(ji)異(yi)常，電(dian)(dian)動(dong)機(ji)(ji)運行中應沒有(you)振(zhen)動(dong)、噪(zao)聲和異(yi)味(wei)。若出現(xian)振(zhen)動(dong)，則(ze)(ze)會引起(qi)電(dian)(dian)動(dong)機(ji)(ji)相(xiang)連(lian)接的(de)負載(zai)作機(ji)(ji)的(de)軸心(xin)不同心(xin)度的(de)增大，進而負荷(he)增大，負荷(he)電(dian)(dian)流也(ye)隨之增大，導致(zhi)溫度升高而燒毀電(dian)(dian)機(ji)(ji)。因此(ci)，要經常檢查引起(qi)振(zhen)動(dong)的(de)地腳螺栓、電(dian)(dian)動(dong)機(ji)(ji)端蓋、軸承壓蓋等處(chu)，不得有(you)松動(dong)，連(lian)接裝置必(bi)須(xu)可(ke)靠，尤其(qi)對大功(gong)率(lv)的(de)電(dian)(dian)機(ji)(ji)，必(bi)須(xu)及(ji)時(shi)發現(xian)及(ji)時(shi)排(pai)除(chu)。噪(zao)聲和異(yi)味(wei)是電(dian)(dian)機(ji)(ji)運行異(yi)常的(de)重要標志，也(ye)是重大事故的(de)前兆，必(bi)須(xu)及(ji)時(shi)發現(xian)，立即查明原因加以(yi)排(pai)除(chu)，否(fou)則(ze)(ze)延誤時(shi)機(ji)(ji)，擴大故障范圍，釀成燒毀電(dian)(dian)動(dong)機(ji)(ji)的(de)嚴重事故。