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)看外觀：電(dian)(dian)動機(ji)(ji)表面油(you)漆(qi)層應(ying)光滑平(ping)(ping)整(zheng)，銘牌(pai)安裝(zhuang)端正，標志(zhi)齊(qi)全；封(feng)閉式(shi)電(dian)(dian)動機(ji)(ji)座(zuo)散熱筋應(ying)完整(zheng)無(wu)損，附件齊(qi)全；⑵手(shou)動旋(xuan)轉：用手(shou)轉動電(dian)(dian)軸、轉動應(ying)很靈活，慣動量(liang)(liang)較(jiao)好，軸向基本無(wu)竄動量(liang)(liang)；⑶診聽軸承：通電(dian)(dian)運(yun)行(xing)15-25分鐘，軸承應(ying)平(ping)(ping)穩輕(qing)快(kuai)，無(wu)停(ting)滯現象(xiang)。聲音均勻和(he)(he)諧；軸承溫度不(bu)高，沒有(you)漏油(you)、甩油(you)現象(xiang)；運(yun)行(xing)停(ting)止后，用手(shou)摸電(dian)(dian)動機(ji)(ji)座(zuo)和(he)(he)端蓋不(bu)感(gan)到發熱；⑷檢查(cha)接(jie)線(xian)：打開接(jie)線(xian)盒看各相(xiang)(xiang)(xiang)(xiang)相(xiang)(xiang)(xiang)(xiang)線(xian)標志(zhi)是(shi)否(fou)清(qing)晰完整(zheng)，聯絡片是(shi)否(fou)壓實壓緊，螺母是(shi)否(fou)齊(qi)全；⑸測(ce)量(liang)(liang)電(dian)(dian)阻：用額定電(dian)(dian)壓500V的(de)(de)手(shou)動式(shi)兆歐表，測(ce)量(liang)(liang)出線(xian)端相(xiang)(xiang)(xiang)(xiang)線(xian)與(yu)相(xiang)(xiang)(xiang)(xiang)線(xian)之(zhi)(zhi)間及線(xian)對機(ji)(ji)座(zuo)之(zhi)(zhi)間的(de)(de)絕(jue)緣電(dian)(dian)阻，正常電(dian)(dian)機(ji)(ji)的(de)(de)絕(jue)緣電(dian)(dian)阻應(ying)大于(yu)1兆歐。⑹測(ce)量(liang)(liang)電(dian)(dian)流。在運(yun)行(xing)中用鉗型(xing)電(dian)(dian)流表測(ce)電(dian)(dian)機(ji)(ji)空載時(shi)各相(xiang)(xiang)(xiang)(xiang)的(de)(de)電(dian)(dian)流，三相(xiang)(xiang)(xiang)(xiang)電(dian)(dian)流中任何一相(xiang)(xiang)(xiang)(xiang)與(yu)三相(xiang)(xiang)(xiang)(xiang)平(ping)(ping)均值的(de)(de)偏差不(bu)得大于(yu)平(ping)(ping)均值的(de)(de)10%，空載電(dian)(dian)流一般為額定電(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(bao)持(chi)啟(qi)動設備(bei)技(ji)術(shu)狀態完好(hao)，電動機啟(qi)動設備(bei)技(ji)術(shu)狀態的(de)(de)(de)(de)好(hao)壞直接(jie)(jie)(jie)關系到(dao)能否(fou)順(shun)利(li)啟(qi)動。實踐表(biao)明，絕大(da)(da)多數燒(shao)毀的(de)(de)(de)(de)電動機都是啟(qi)動不(bu)(bu)順(shun)利(li)而(er)(er)燒(shao)毀的(de)(de)(de)(de)，如啟(qi)動設備(bei)技(ji)術(shu)狀態不(bu)(bu)良引(yin)發的(de)(de)(de)(de)缺(que)相(xiang)啟(qi)動；接(jie)(jie)(jie)觸(chu)(chu)(chu)器觸(chu)(chu)(chu)頭拉弧、打火而(er)(er)導致(zhi)電壓、電流大(da)(da)幅(fu)度(du)改變等。保(bao)持(chi)啟(qi)動設備(bei)技(ji)術(shu)狀態良好(hao)的(de)(de)(de)(de)措(cuo)施是：經常(chang)(chang)做檢(jian)查(cha)(cha)、清潔(jie)、緊固工作。若接(jie)(jie)(jie)觸(chu)(chu)(chu)器觸(chu)(chu)(chu)頭不(bu)(bu)清潔(jie)，氧化(hua)燒(shao)蝕(shi)嚴重(zhong)，則會產生接(jie)(jie)(jie)觸(chu)(chu)(chu)電阻增大(da)(da)，引(yin)起發熱、燒(shao)蝕(shi)觸(chu)(chu)(chu)點，從而(er)(er)形成缺(que)相(xiang)運行而(er)(er)燒(shao)毀電機繞組；接(jie)(jie)(jie)觸(chu)(chu)(chu)器吸合(he)線(xian)圈鐵(tie)芯有銹蝕(shi)和灰塵(chen)，會使吸合(he)不(bu)(bu)嚴而(er)(er)發出強烈(lie)噪聲(sheng)，并增大(da)(da)線(xian)圈電流，直至燒(shao)毀線(xian)圈。因此，電氣(qi)控制柜應(ying)設在(zai)干(gan)燥、通風和便于(yu)操作的(de)(de)(de)(de)位置；還要定期除塵(chen)、清理觸(chu)(chu)(chu)點；線(xian)圈鐵(tie)芯要增加防(fang)銹措(cuo)施；要經常(chang)(chang)緊固各連接(jie)(jie)(jie)部件(jian)；檢(jian)查(cha)(cha)接(jie)(jie)(jie)觸(chu)(chu)(chu)器觸(chu)(chu)(chu)點，保(bao)證接(jie)(jie)(jie)觸(chu)(chu)(chu)良好(hao)，機構(gou)動作應(ying)靈活、準(zhun)確，這(zhe)些是保(bao)證啟(qi)動順(shun)利(li)的(de)(de)(de)(de)必(bi)然條件(jian)。

2、保持(chi)電(dian)(dian)(dian)動(dong)機(ji)清潔和(he)良(liang)好的(de)(de)冷卻環境，在電(dian)(dian)(dian)動(dong)機(ji)的(de)(de)進(jin)風口處(chu)，必(bi)須經常保持(chi)清潔。進(jin)風口的(de)(de)周圍不得(de)有塵(chen)土(tu)、油污、水漬和(he)其它秸稈雜物，以防止這類(lei)東(dong)西吸(xi)入(ru)電(dian)(dian)(dian)機(ji)內部，形成短路介質或(huo)損(sun)傷電(dian)(dian)(dian)機(ji)繞組(zu)絕緣層；或(huo)阻斷電(dian)(dian)(dian)機(ji)的(de)(de)通風冷卻而溫度升高，導(dao)致燒毀(hui)。

3、保(bao)持(chi)電(dian)(dian)(dian)動機(ji)在(zai)額(e)定電(dian)(dian)(dian)流(liu)下工作(zuo)，避免農(nong)用電(dian)(dian)(dian)動機(ji)的(de)(de)過(guo)載(zai)運(yun)行。當(dang)電(dian)(dian)(dian)動機(ji)處于過(guo)載(zai)狀態運(yun)行時，電(dian)(dian)(dian)動機(ji)轉速下降，電(dian)(dian)(dian)流(liu)增大，溫度(du)(du)升(sheng)高，繞(rao)組(zu)線(xian)圈過(guo)熱。其主(zhu)(zhu)要(yao)原因(yin)是(shi)拖(tuo)動負荷過(guo)大，電(dian)(dian)(dian)壓(ya)過(guo)低或被拖(tuo)動的(de)(de)機(ji)械卡(ka)滯(zhi)等造成的(de)(de)；若過(guo)載(zai)時間稍長，過(guo)載(zai)電(dian)(dian)(dian)機(ji)從(cong)電(dian)(dian)(dian)網中吸收大量有功(gong)功(gong)率，電(dian)(dian)(dian)流(liu)便急劇增加(jia)，隨之(zhi)溫度(du)(du)上升(sheng)。在(zai)高溫下運(yun)行的(de)(de)電(dian)(dian)(dian)機(ji)，絕緣材料(liao)易(yi)老化(hua)失效(xiao)而燒(shao)毀(hui)繞(rao)組(zu)線(xian)圈，這是(shi)燒(shao)毀(hui)電(dian)(dian)(dian)機(ji)的(de)(de)主(zhu)(zhu)要(yao)原因(yin)。因(yin)此，一(yi)要(yao)經常注意(yi)檢查機(ji)組(zu)傳動裝置是(shi)否運(yun)轉靈(ling)活(huo)、可靠，隨時檢查、調整傳動皮帶松緊度(du)(du)，防止卡(ka)滯(zhi)；二要(yao)注意(yi)作(zuo)業機(ji)械不(bu)要(yao)較長時間超負荷工作(zuo)；三要(yao)保(bao)持(chi)電(dian)(dian)(dian)壓(ya)穩定，尤(you)其不(bu)得低壓(ya)運(yun)轉，從(cong)而確保(bao)電(dian)(dian)(dian)動機(ji)在(zai)額(e)定電(dian)(dian)(dian)流(liu)下正常工作(zuo)。

4、保(bao)持相間電(dian)(dian)流(liu)平衡。農用(yong)三(san)相異步(bu)電(dian)(dian)動(dong)機，其中任何一相的電(dian)(dian)流(liu)值與其他兩相電(dian)(dian)流(liu)平均值之差不得超(chao)(chao)過(guo)10%，這是保(bao)證電(dian)(dian)動(dong)機安全運轉的必(bi)要條件(jian)。如果(guo)這個差值超(chao)(chao)過(guo)10%，則表明電(dian)(dian)動(dong)機已(yi)經出(chu)現故障(zhang)，必(bi)須(xu)立即停機查明原因，并排除故障(zhang)后方能繼續工(gong)作，否則故障(zhang)會(hui)迅速擴大(da)，直(zhi)至燒(shao)毀(hui)電(dian)(dian)動(dong)機。

5、保(bao)持電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)溫(wen)(wen)度(du)和溫(wen)(wen)升(sheng)在正常范圍內(nei)(nei)(nei)。電(dian)(dian)機(ji)(ji)(ji)運行(xing)中，要(yao)隨時檢(jian)(jian)查軸承(cheng)(cheng)、定(ding)子(zi)、外(wai)殼等(deng)部位的(de)溫(wen)(wen)度(du)有無(wu)異常，特別(bie)是(shi)對沒有過載保(bao)護(hu)的(de)電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)，監視溫(wen)(wen)度(du)更(geng)為重要(yao)。如軸承(cheng)(cheng)缺油或(huo)(huo)損(sun)壞，則(ze)必然引起溫(wen)(wen)度(du)升(sheng)高。在軸承(cheng)(cheng)附(fu)近(jin)機(ji)(ji)(ji)體(ti)溫(wen)(wen)度(du)升(sheng)高，就要(yao)立即停機(ji)(ji)(ji)檢(jian)(jian)查軸承(cheng)(cheng)，可(ke)先加(jia)油，若(ruo)仍然無(wu)效，則(ze)應拆下(xia)軸承(cheng)(cheng)鑒定(ding)。若(ruo)滾動(dong)(dong)體(ti)、滾道表面(mian)有裂紋(wen)、劃傷或(huo)(huo)損(sun)壞，或(huo)(huo)間隙變(bian)大，內(nei)(nei)(nei)環在軸承(cheng)(cheng)上有轉動(dong)(dong)，出現任何一(yi)項，都應更(geng)換軸承(cheng)(cheng)。否(fou)則(ze)繼續使(shi)(shi)用會使(shi)(shi)軸承(cheng)(cheng)進一(yi)步損(sun)壞，導致塌架(jia)、電(dian)(dian)機(ji)(ji)(ji)掃膛燒毀等(deng)重大事故。監測電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)的(de)溫(wen)(wen)度(du)或(huo)(huo)溫(wen)(wen)升(sheng)有無(wu)變(bian)化(hua)，可(ke)用下(xia)述簡單方法監視：在電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)的(de)孔內(nei)(nei)(nei)，插支溫(wen)(wen)度(du)計，用棉(mian)花(hua)團塞緊(jin)固定(ding)，便可(ke)隨時監視電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)溫(wen)(wen)度(du)的(de)變(bian)化(hua)，機(ji)(ji)(ji)外(wai)與殼內(nei)(nei)(nei)溫(wen)(wen)差通常為1℃。

6、及(ji)時發現(xian)和處理電(dian)(dian)機(ji)異(yi)(yi)常(chang)，電(dian)(dian)動(dong)(dong)機(ji)運(yun)行中應沒有振(zhen)動(dong)(dong)、噪(zao)聲(sheng)和異(yi)(yi)味。若(ruo)出現(xian)振(zhen)動(dong)(dong)，則(ze)會引起電(dian)(dian)動(dong)(dong)機(ji)相連接的(de)(de)(de)負(fu)載作機(ji)的(de)(de)(de)軸(zhou)(zhou)心不同心度的(de)(de)(de)增大(da)，進而(er)負(fu)荷(he)增大(da)，負(fu)荷(he)電(dian)(dian)流也隨之增大(da)，導致溫度升高而(er)燒毀(hui)電(dian)(dian)機(ji)。因(yin)此，要經常(chang)檢查(cha)引起振(zhen)動(dong)(dong)的(de)(de)(de)地腳(jiao)螺栓、電(dian)(dian)動(dong)(dong)機(ji)端蓋、軸(zhou)(zhou)承(cheng)壓(ya)蓋等處，不得(de)有松動(dong)(dong)，連接裝置必須可靠，尤其對大(da)功率的(de)(de)(de)電(dian)(dian)機(ji)，必須及(ji)時發現(xian)及(ji)時排除。噪(zao)聲(sheng)和異(yi)(yi)味是電(dian)(dian)機(ji)運(yun)行異(yi)(yi)常(chang)的(de)(de)(de)重要標志(zhi)，也是重大(da)事故(gu)的(de)(de)(de)前兆，必須及(ji)時發現(xian)，立即查(cha)明(ming)原因(yin)加以排除，否則(ze)延誤(wu)時機(ji)，擴大(da)故(gu)障范圍，釀成(cheng)燒毀(hui)電(dian)(dian)動(dong)(dong)機(ji)的(de)(de)(de)嚴(yan)重事故(gu)。