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)(kan)外(wai)觀：電(dian)(dian)(dian)(dian)動機(ji)表面油(you)(you)漆層應(ying)光滑平(ping)(ping)整(zheng)(zheng)，銘牌(pai)安裝端(duan)正(zheng)(zheng)，標(biao)志(zhi)齊全(quan)；封閉式(shi)電(dian)(dian)(dian)(dian)動機(ji)座(zuo)散熱(re)(re)筋應(ying)完整(zheng)(zheng)無損，附(fu)件齊全(quan)；⑵手動旋(xuan)轉(zhuan)(zhuan)：用手轉(zhuan)(zhuan)動電(dian)(dian)(dian)(dian)軸、轉(zhuan)(zhuan)動應(ying)很靈(ling)活(huo)，慣動量(liang)較好(hao)，軸向基本無竄動量(liang)；⑶診(zhen)聽(ting)軸承：通電(dian)(dian)(dian)(dian)運(yun)(yun)行(xing)15-25分鐘(zhong)，軸承應(ying)平(ping)(ping)穩輕(qing)快(kuai)，無停滯(zhi)現象。聲(sheng)音均(jun)勻和(he)諧(xie)；軸承溫度(du)不高，沒(mei)有漏油(you)(you)、甩油(you)(you)現象；運(yun)(yun)行(xing)停止后，用手摸電(dian)(dian)(dian)(dian)動機(ji)座(zuo)和(he)端(duan)蓋(gai)不感(gan)到發熱(re)(re)；⑷檢查接線：打開接線盒看(kan)(kan)各(ge)相(xiang)(xiang)相(xiang)(xiang)線標(biao)志(zhi)是(shi)否清(qing)晰完整(zheng)(zheng)，聯絡片是(shi)否壓實壓緊，螺母(mu)是(shi)否齊全(quan)；⑸測(ce)量(liang)電(dian)(dian)(dian)(dian)阻(zu)(zu)：用額定電(dian)(dian)(dian)(dian)壓500V的手動式(shi)兆歐(ou)表，測(ce)量(liang)出線端(duan)相(xiang)(xiang)線與相(xiang)(xiang)線之(zhi)間(jian)及(ji)線對機(ji)座(zuo)之(zhi)間(jian)的絕緣(yuan)(yuan)電(dian)(dian)(dian)(dian)阻(zu)(zu)，正(zheng)(zheng)常電(dian)(dian)(dian)(dian)機(ji)的絕緣(yuan)(yuan)電(dian)(dian)(dian)(dian)阻(zu)(zu)應(ying)大于1兆歐(ou)。⑹測(ce)量(liang)電(dian)(dian)(dian)(dian)流(liu)。在運(yun)(yun)行(xing)中用鉗(qian)型(xing)電(dian)(dian)(dian)(dian)流(liu)表測(ce)電(dian)(dian)(dian)(dian)機(ji)空載(zai)時各(ge)相(xiang)(xiang)的電(dian)(dian)(dian)(dian)流(liu)，三(san)相(xiang)(xiang)電(dian)(dian)(dian)(dian)流(liu)中任何一相(xiang)(xiang)與三(san)相(xiang)(xiang)平(ping)(ping)均(jun)值的偏差(cha)不得大于平(ping)(ping)均(jun)值的10%，空載(zai)電(dian)(dian)(dian)(dian)流(liu)一般為額定電(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)(dong)(dong)設備技(ji)(ji)(ji)術狀(zhuang)態(tai)完好(hao)，電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機啟(qi)(qi)動(dong)(dong)(dong)(dong)設備技(ji)(ji)(ji)術狀(zhuang)態(tai)的好(hao)壞直接(jie)關(guan)系到能否順(shun)利(li)啟(qi)(qi)動(dong)(dong)(dong)(dong)。實(shi)踐(jian)表明，絕大多數燒(shao)毀的電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)(dong)機都是(shi)(shi)(shi)啟(qi)(qi)動(dong)(dong)(dong)(dong)不(bu)(bu)順(shun)利(li)而(er)(er)(er)燒(shao)毀的，如(ru)啟(qi)(qi)動(dong)(dong)(dong)(dong)設備技(ji)(ji)(ji)術狀(zhuang)態(tai)不(bu)(bu)良引(yin)發(fa)的缺相啟(qi)(qi)動(dong)(dong)(dong)(dong)；接(jie)觸(chu)(chu)(chu)(chu)器觸(chu)(chu)(chu)(chu)頭拉(la)弧、打(da)火而(er)(er)(er)導(dao)致電(dian)(dian)(dian)(dian)壓、電(dian)(dian)(dian)(dian)流(liu)大幅(fu)度改變等。保持(chi)啟(qi)(qi)動(dong)(dong)(dong)(dong)設備技(ji)(ji)(ji)術狀(zhuang)態(tai)良好(hao)的措施(shi)是(shi)(shi)(shi)：經(jing)常做檢查、清(qing)(qing)潔、緊固(gu)(gu)工作(zuo)(zuo)。若(ruo)接(jie)觸(chu)(chu)(chu)(chu)器觸(chu)(chu)(chu)(chu)頭不(bu)(bu)清(qing)(qing)潔，氧化燒(shao)蝕嚴重，則(ze)會產生(sheng)接(jie)觸(chu)(chu)(chu)(chu)電(dian)(dian)(dian)(dian)阻增(zeng)大，引(yin)起發(fa)熱、燒(shao)蝕觸(chu)(chu)(chu)(chu)點，從而(er)(er)(er)形成缺相運行而(er)(er)(er)燒(shao)毀電(dian)(dian)(dian)(dian)機繞組；接(jie)觸(chu)(chu)(chu)(chu)器吸(xi)合(he)線圈鐵(tie)芯(xin)有銹蝕和(he)灰塵，會使(shi)吸(xi)合(he)不(bu)(bu)嚴而(er)(er)(er)發(fa)出強烈噪聲(sheng)，并增(zeng)大線圈電(dian)(dian)(dian)(dian)流(liu)，直至燒(shao)毀線圈。因此，電(dian)(dian)(dian)(dian)氣控制柜應設在干燥、通風(feng)和(he)便于操作(zuo)(zuo)的位置；還要定期(qi)除塵、清(qing)(qing)理觸(chu)(chu)(chu)(chu)點；線圈鐵(tie)芯(xin)要增(zeng)加防銹措施(shi)；要經(jing)常緊固(gu)(gu)各連(lian)接(jie)部件(jian)(jian)；檢查接(jie)觸(chu)(chu)(chu)(chu)器觸(chu)(chu)(chu)(chu)點，保證接(jie)觸(chu)(chu)(chu)(chu)良好(hao)，機構動(dong)(dong)(dong)(dong)作(zuo)(zuo)應靈活、準確，這些是(shi)(shi)(shi)保證啟(qi)(qi)動(dong)(dong)(dong)(dong)順(shun)利(li)的必(bi)然條件(jian)(jian)。

2、保持電(dian)動(dong)機(ji)(ji)清潔和(he)(he)良好的(de)(de)冷卻(que)環境，在(zai)電(dian)動(dong)機(ji)(ji)的(de)(de)進風口(kou)處，必須經常(chang)保持清潔。進風口(kou)的(de)(de)周圍不(bu)得有(you)塵土、油(you)污、水漬和(he)(he)其它秸稈(gan)雜物，以防止這類東西(xi)吸入電(dian)機(ji)(ji)內部，形成(cheng)短路介質或損傷電(dian)機(ji)(ji)繞組絕緣層(ceng)；或阻斷電(dian)機(ji)(ji)的(de)(de)通風冷卻(que)而溫度升高，導(dao)致燒毀。

3、保(bao)(bao)持電(dian)動(dong)機(ji)(ji)在額定(ding)電(dian)流(liu)下(xia)工(gong)作，避免農用電(dian)動(dong)機(ji)(ji)的(de)(de)(de)(de)過(guo)載運(yun)行。當電(dian)動(dong)機(ji)(ji)處(chu)于過(guo)載狀(zhuang)態運(yun)行時(shi)，電(dian)動(dong)機(ji)(ji)轉(zhuan)速下(xia)降，電(dian)流(liu)增大(da)，溫度(du)(du)升高(gao)，繞組線圈(quan)過(guo)熱。其(qi)主要(yao)(yao)(yao)原因是(shi)拖動(dong)負荷(he)過(guo)大(da)，電(dian)壓過(guo)低或被拖動(dong)的(de)(de)(de)(de)機(ji)(ji)械卡滯(zhi)等(deng)造成的(de)(de)(de)(de)；若過(guo)載時(shi)間(jian)稍(shao)長，過(guo)載電(dian)機(ji)(ji)從(cong)電(dian)網(wang)中吸(xi)收大(da)量(liang)有功功率，電(dian)流(liu)便急劇(ju)增加(jia)，隨(sui)之溫度(du)(du)上(shang)升。在高(gao)溫下(xia)運(yun)行的(de)(de)(de)(de)電(dian)機(ji)(ji)，絕緣材料易老化失效而(er)燒毀(hui)繞組線圈(quan)，這是(shi)燒毀(hui)電(dian)機(ji)(ji)的(de)(de)(de)(de)主要(yao)(yao)(yao)原因。因此，一要(yao)(yao)(yao)經常(chang)注意檢查(cha)機(ji)(ji)組傳動(dong)裝置是(shi)否(fou)運(yun)轉(zhuan)靈活(huo)、可靠，隨(sui)時(shi)檢查(cha)、調(diao)整傳動(dong)皮帶松緊度(du)(du)，防止卡滯(zhi)；二(er)要(yao)(yao)(yao)注意作業(ye)機(ji)(ji)械不(bu)要(yao)(yao)(yao)較長時(shi)間(jian)超(chao)負荷(he)工(gong)作；三要(yao)(yao)(yao)保(bao)(bao)持電(dian)壓穩(wen)定(ding)，尤(you)其(qi)不(bu)得低壓運(yun)轉(zhuan)，從(cong)而(er)確保(bao)(bao)電(dian)動(dong)機(ji)(ji)在額定(ding)電(dian)流(liu)下(xia)正常(chang)工(gong)作。

4、保持相(xiang)間電(dian)(dian)(dian)流(liu)平衡。農用(yong)三相(xiang)異(yi)步(bu)電(dian)(dian)(dian)動機(ji)，其(qi)(qi)中(zhong)任何一相(xiang)的(de)電(dian)(dian)(dian)流(liu)值與其(qi)(qi)他兩相(xiang)電(dian)(dian)(dian)流(liu)平均值之差不得超(chao)過10%，這(zhe)(zhe)是(shi)保證電(dian)(dian)(dian)動機(ji)安全運轉的(de)必要條件(jian)。如果這(zhe)(zhe)個差值超(chao)過10%，則表(biao)明電(dian)(dian)(dian)動機(ji)已經(jing)出現故障(zhang)，必須(xu)立即停機(ji)查明原因(yin)，并排(pai)除故障(zhang)后方(fang)能繼續工(gong)作，否則故障(zhang)會迅速擴大(da)，直至燒毀電(dian)(dian)(dian)動機(ji)。

5、保(bao)持電(dian)(dian)動(dong)(dong)機(ji)溫(wen)度和(he)溫(wen)升(sheng)在正常(chang)范(fan)圍內(nei)。電(dian)(dian)機(ji)運(yun)行中，要隨時(shi)檢查(cha)軸(zhou)(zhou)(zhou)承、定(ding)子、外(wai)殼等部(bu)位的溫(wen)度有(you)無異常(chang)，特(te)別是對(dui)沒有(you)過載保(bao)護的電(dian)(dian)動(dong)(dong)機(ji)，監視(shi)(shi)溫(wen)度更為(wei)重要。如軸(zhou)(zhou)(zhou)承缺油或(huo)損壞，則必然引起溫(wen)度升(sheng)高。在軸(zhou)(zhou)(zhou)承附(fu)近機(ji)體(ti)溫(wen)度升(sheng)高，就要立即停機(ji)檢查(cha)軸(zhou)(zhou)(zhou)承，可先加油，若仍然無效，則應(ying)(ying)拆下軸(zhou)(zhou)(zhou)承鑒(jian)定(ding)。若滾動(dong)(dong)體(ti)、滾道表面有(you)裂紋(wen)、劃傷(shang)或(huo)損壞，或(huo)間隙變(bian)(bian)大，內(nei)環在軸(zhou)(zhou)(zhou)承上有(you)轉動(dong)(dong)，出現(xian)任(ren)何一項，都應(ying)(ying)更換軸(zhou)(zhou)(zhou)承。否(fou)則繼續使(shi)用會使(shi)軸(zhou)(zhou)(zhou)承進(jin)一步(bu)損壞，導致塌(ta)架(jia)、電(dian)(dian)機(ji)掃膛燒(shao)毀(hui)等重大事(shi)故。監測電(dian)(dian)動(dong)(dong)機(ji)的溫(wen)度或(huo)溫(wen)升(sheng)有(you)無變(bian)(bian)化，可用下述簡(jian)單方法監視(shi)(shi)：在電(dian)(dian)動(dong)(dong)機(ji)的孔內(nei)，插支溫(wen)度計，用棉花團塞(sai)緊(jin)固(gu)定(ding)，便可隨時(shi)監視(shi)(shi)電(dian)(dian)動(dong)(dong)機(ji)溫(wen)度的變(bian)(bian)化，機(ji)外(wai)與殼內(nei)溫(wen)差(cha)通常(chang)為(wei)1℃。

6、及(ji)時(shi)(shi)發(fa)現(xian)(xian)(xian)和處理電(dian)(dian)機(ji)(ji)異(yi)常(chang)，電(dian)(dian)動(dong)(dong)機(ji)(ji)運(yun)(yun)行中應沒有振(zhen)動(dong)(dong)、噪聲和異(yi)味。若(ruo)出現(xian)(xian)(xian)振(zhen)動(dong)(dong)，則會引起電(dian)(dian)動(dong)(dong)機(ji)(ji)相連接(jie)的(de)負載作機(ji)(ji)的(de)軸(zhou)心(xin)不(bu)同心(xin)度的(de)增大(da)(da)，進而(er)負荷(he)增大(da)(da)，負荷(he)電(dian)(dian)流也隨之增大(da)(da)，導致溫度升高而(er)燒毀(hui)電(dian)(dian)機(ji)(ji)。因(yin)此，要經常(chang)檢查(cha)引起振(zhen)動(dong)(dong)的(de)地腳螺栓、電(dian)(dian)動(dong)(dong)機(ji)(ji)端蓋、軸(zhou)承(cheng)壓蓋等處，不(bu)得有松動(dong)(dong)，連接(jie)裝置必須(xu)可靠，尤其對大(da)(da)功率(lv)的(de)電(dian)(dian)機(ji)(ji)，必須(xu)及(ji)時(shi)(shi)發(fa)現(xian)(xian)(xian)及(ji)時(shi)(shi)排(pai)除(chu)。噪聲和異(yi)味是電(dian)(dian)機(ji)(ji)運(yun)(yun)行異(yi)常(chang)的(de)重(zhong)(zhong)要標志，也是重(zhong)(zhong)大(da)(da)事故的(de)前兆，必須(xu)及(ji)時(shi)(shi)發(fa)現(xian)(xian)(xian)，立(li)即(ji)查(cha)明原因(yin)加以排(pai)除(chu)，否(fou)則延誤(wu)時(shi)(shi)機(ji)(ji)，擴大(da)(da)故障范圍，釀成(cheng)燒毀(hui)電(dian)(dian)動(dong)(dong)機(ji)(ji)的(de)嚴重(zhong)(zhong)事故。