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)動(dong)(dong)機(ji)(ji)表(biao)(biao)面油漆層應(ying)光滑平(ping)整，銘牌安裝端正，標(biao)(biao)志齊全(quan)；封閉式電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)座(zuo)散熱筋應(ying)完整無損(sun)，附件齊全(quan)；⑵手(shou)(shou)(shou)動(dong)(dong)旋轉(zhuan)：用手(shou)(shou)(shou)轉(zhuan)動(dong)(dong)電(dian)(dian)(dian)軸、轉(zhuan)動(dong)(dong)應(ying)很(hen)靈(ling)活，慣動(dong)(dong)量(liang)較(jiao)好，軸向基本無竄動(dong)(dong)量(liang)；⑶診聽(ting)軸承：通電(dian)(dian)(dian)運行(xing)15-25分鐘，軸承應(ying)平(ping)穩輕快(kuai)，無停滯現象。聲(sheng)音均勻和諧(xie)；軸承溫度(du)不(bu)高(gao)，沒有漏油、甩油現象；運行(xing)停止后，用手(shou)(shou)(shou)摸電(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)座(zuo)和端蓋不(bu)感到(dao)發熱；⑷檢(jian)查(cha)接(jie)線：打開接(jie)線盒(he)看(kan)各(ge)相(xiang)相(xiang)線標(biao)(biao)志是(shi)否清晰完整，聯絡片是(shi)否壓(ya)實壓(ya)緊，螺母(mu)是(shi)否齊全(quan)；⑸測(ce)(ce)量(liang)電(dian)(dian)(dian)阻：用額(e)定(ding)電(dian)(dian)(dian)壓(ya)500V的(de)(de)手(shou)(shou)(shou)動(dong)(dong)式兆歐表(biao)(biao)，測(ce)(ce)量(liang)出線端相(xiang)線與相(xiang)線之間(jian)及線對機(ji)(ji)座(zuo)之間(jian)的(de)(de)絕(jue)緣電(dian)(dian)(dian)阻，正常電(dian)(dian)(dian)機(ji)(ji)的(de)(de)絕(jue)緣電(dian)(dian)(dian)阻應(ying)大于1兆歐。⑹測(ce)(ce)量(liang)電(dian)(dian)(dian)流。在運行(xing)中(zhong)用鉗型電(dian)(dian)(dian)流表(biao)(biao)測(ce)(ce)電(dian)(dian)(dian)機(ji)(ji)空載時(shi)各(ge)相(xiang)的(de)(de)電(dian)(dian)(dian)流，三相(xiang)電(dian)(dian)(dian)流中(zhong)任何一相(xiang)與三相(xiang)平(ping)均值(zhi)的(de)(de)偏差不(bu)得大于平(ping)均值(zhi)的(de)(de)10%，空載電(dian)(dian)(dian)流一般為額(e)定(ding)電(dian)(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、保持啟(qi)動(dong)設(she)備技(ji)術(shu)狀(zhuang)態完(wan)好，電(dian)(dian)(dian)動(dong)機啟(qi)動(dong)設(she)備技(ji)術(shu)狀(zhuang)態的(de)好壞直(zhi)(zhi)接(jie)關系到(dao)能否順(shun)利(li)(li)啟(qi)動(dong)。實踐表明(ming)，絕大(da)多數燒毀的(de)電(dian)(dian)(dian)動(dong)機都是啟(qi)動(dong)不(bu)順(shun)利(li)(li)而(er)(er)燒毀的(de)，如啟(qi)動(dong)設(she)備技(ji)術(shu)狀(zhuang)態不(bu)良引(yin)發(fa)的(de)缺(que)相啟(qi)動(dong)；接(jie)觸(chu)器觸(chu)頭拉弧、打火(huo)而(er)(er)導致電(dian)(dian)(dian)壓、電(dian)(dian)(dian)流(liu)大(da)幅度改變等。保持啟(qi)動(dong)設(she)備技(ji)術(shu)狀(zhuang)態良好的(de)措(cuo)(cuo)施是：經常做檢查、清(qing)潔(jie)、緊(jin)固(gu)工作(zuo)。若接(jie)觸(chu)器觸(chu)頭不(bu)清(qing)潔(jie)，氧(yang)化(hua)燒蝕嚴重，則會產生接(jie)觸(chu)電(dian)(dian)(dian)阻(zu)增大(da)，引(yin)起發(fa)熱、燒蝕觸(chu)點，從而(er)(er)形(xing)成缺(que)相運(yun)行而(er)(er)燒毀電(dian)(dian)(dian)機繞(rao)組；接(jie)觸(chu)器吸合(he)線(xian)圈(quan)鐵芯有銹蝕和灰塵，會使吸合(he)不(bu)嚴而(er)(er)發(fa)出強烈噪聲(sheng)，并(bing)增大(da)線(xian)圈(quan)電(dian)(dian)(dian)流(liu)，直(zhi)(zhi)至燒毀線(xian)圈(quan)。因此，電(dian)(dian)(dian)氣(qi)控(kong)制(zhi)柜應(ying)(ying)設(she)在干燥、通(tong)風和便于(yu)操作(zuo)的(de)位(wei)置；還(huan)要定期除塵、清(qing)理觸(chu)點；線(xian)圈(quan)鐵芯要增加防銹措(cuo)(cuo)施；要經常緊(jin)固(gu)各連接(jie)部件；檢查接(jie)觸(chu)器觸(chu)點，保證(zheng)接(jie)觸(chu)良好，機構動(dong)作(zuo)應(ying)(ying)靈活、準確，這(zhe)些是保證(zheng)啟(qi)動(dong)順(shun)利(li)(li)的(de)必然條件。

2、保(bao)(bao)持(chi)電(dian)(dian)(dian)動(dong)機(ji)清潔和良好的冷卻環境，在電(dian)(dian)(dian)動(dong)機(ji)的進風(feng)口處，必須經常保(bao)(bao)持(chi)清潔。進風(feng)口的周圍不得有塵土、油(you)污、水漬(zi)和其它秸(jie)稈(gan)雜物，以防止(zhi)這(zhe)類東西吸入電(dian)(dian)(dian)機(ji)內部(bu)，形(xing)成短路介質或(huo)損傷(shang)電(dian)(dian)(dian)機(ji)繞組絕緣層；或(huo)阻(zu)斷(duan)電(dian)(dian)(dian)機(ji)的通(tong)風(feng)冷卻而溫度升高，導致(zhi)燒毀。

3、保持電(dian)動機(ji)(ji)(ji)(ji)在(zai)額定(ding)電(dian)流(liu)(liu)下(xia)工作(zuo)，避免農用電(dian)動機(ji)(ji)(ji)(ji)的過載運行(xing)。當(dang)電(dian)動機(ji)(ji)(ji)(ji)處于過載狀態運行(xing)時(shi)，電(dian)動機(ji)(ji)(ji)(ji)轉(zhuan)(zhuan)速下(xia)降，電(dian)流(liu)(liu)增大(da)，溫度升高，繞(rao)(rao)組(zu)線圈(quan)過熱(re)。其主要(yao)原因是(shi)拖動負荷(he)過大(da)，電(dian)壓(ya)過低(di)或被拖動的機(ji)(ji)(ji)(ji)械卡滯等造成的；若過載時(shi)間(jian)稍長，過載電(dian)機(ji)(ji)(ji)(ji)從(cong)電(dian)網中吸收大(da)量有功(gong)功(gong)率，電(dian)流(liu)(liu)便急劇增加，隨(sui)之(zhi)溫度上升。在(zai)高溫下(xia)運行(xing)的電(dian)機(ji)(ji)(ji)(ji)，絕(jue)緣材(cai)料易老化失效而燒(shao)毀繞(rao)(rao)組(zu)線圈(quan)，這(zhe)是(shi)燒(shao)毀電(dian)機(ji)(ji)(ji)(ji)的主要(yao)原因。因此，一要(yao)經(jing)常注意檢查機(ji)(ji)(ji)(ji)組(zu)傳動裝(zhuang)置(zhi)是(shi)否運轉(zhuan)(zhuan)靈(ling)活、可(ke)靠，隨(sui)時(shi)檢查、調整傳動皮帶松緊(jin)度，防止卡滯；二要(yao)注意作(zuo)業機(ji)(ji)(ji)(ji)械不(bu)要(yao)較長時(shi)間(jian)超(chao)負荷(he)工作(zuo)；三要(yao)保持電(dian)壓(ya)穩定(ding)，尤(you)其不(bu)得低(di)壓(ya)運轉(zhuan)(zhuan)，從(cong)而確保電(dian)動機(ji)(ji)(ji)(ji)在(zai)額定(ding)電(dian)流(liu)(liu)下(xia)正常工作(zuo)。

4、保(bao)持相間電(dian)(dian)流平衡。農用三相異步電(dian)(dian)動機(ji)，其中任何一相的電(dian)(dian)流值與其他兩相電(dian)(dian)流平均值之差(cha)不得超(chao)過(guo)10%，這(zhe)是保(bao)證電(dian)(dian)動機(ji)安全運轉的必要條(tiao)件。如果這(zhe)個差(cha)值超(chao)過(guo)10%，則表(biao)明電(dian)(dian)動機(ji)已經出現故(gu)(gu)障(zhang)，必須立即停機(ji)查明原因(yin)，并排除故(gu)(gu)障(zhang)后方能繼(ji)續工(gong)作，否則故(gu)(gu)障(zhang)會迅(xun)速擴大，直至燒(shao)毀電(dian)(dian)動機(ji)。

5、保(bao)持電(dian)(dian)動(dong)機(ji)(ji)溫(wen)(wen)度(du)和溫(wen)(wen)升在(zai)正常(chang)范圍內。電(dian)(dian)機(ji)(ji)運行中，要(yao)隨時檢查軸(zhou)承、定(ding)子、外(wai)殼等(deng)部位的(de)溫(wen)(wen)度(du)有(you)(you)無異(yi)常(chang)，特(te)別是對沒有(you)(you)過載保(bao)護的(de)電(dian)(dian)動(dong)機(ji)(ji)，監視溫(wen)(wen)度(du)更為重(zhong)要(yao)。如軸(zhou)承缺油(you)或(huo)損壞(huai)，則必(bi)然引起溫(wen)(wen)度(du)升高。在(zai)軸(zhou)承附(fu)近機(ji)(ji)體(ti)溫(wen)(wen)度(du)升高，就要(yao)立即(ji)停機(ji)(ji)檢查軸(zhou)承，可先(xian)加油(you)，若仍(reng)然無效，則應拆下(xia)軸(zhou)承鑒定(ding)。若滾動(dong)體(ti)、滾道表面有(you)(you)裂紋、劃傷(shang)或(huo)損壞(huai)，或(huo)間(jian)隙變(bian)大(da)，內環在(zai)軸(zhou)承上有(you)(you)轉動(dong)，出現任何一項，都應更換軸(zhou)承。否則繼(ji)續(xu)使用會使軸(zhou)承進一步損壞(huai)，導(dao)致塌架、電(dian)(dian)機(ji)(ji)掃膛燒(shao)毀等(deng)重(zhong)大(da)事故。監測電(dian)(dian)動(dong)機(ji)(ji)的(de)溫(wen)(wen)度(du)或(huo)溫(wen)(wen)升有(you)(you)無變(bian)化(hua)，可用下(xia)述簡單方法監視：在(zai)電(dian)(dian)動(dong)機(ji)(ji)的(de)孔內，插支溫(wen)(wen)度(du)計，用棉花團塞緊固定(ding)，便可隨時監視電(dian)(dian)動(dong)機(ji)(ji)溫(wen)(wen)度(du)的(de)變(bian)化(hua)，機(ji)(ji)外(wai)與殼內溫(wen)(wen)差(cha)通常(chang)為1℃。

6、及(ji)時(shi)(shi)發現(xian)(xian)和(he)處理電(dian)機(ji)(ji)(ji)(ji)異常，電(dian)動(dong)機(ji)(ji)(ji)(ji)運(yun)行(xing)中應(ying)沒有振動(dong)、噪(zao)聲和(he)異味。若出現(xian)(xian)振動(dong)，則會(hui)引(yin)起(qi)電(dian)動(dong)機(ji)(ji)(ji)(ji)相連接(jie)的(de)(de)(de)負(fu)載(zai)作機(ji)(ji)(ji)(ji)的(de)(de)(de)軸心不(bu)同心度(du)的(de)(de)(de)增大(da)，進而負(fu)荷增大(da)，負(fu)荷電(dian)流也隨之增大(da)，導致溫度(du)升高而燒(shao)毀(hui)電(dian)機(ji)(ji)(ji)(ji)。因(yin)此(ci)，要經常檢查引(yin)起(qi)振動(dong)的(de)(de)(de)地腳螺栓、電(dian)動(dong)機(ji)(ji)(ji)(ji)端蓋、軸承壓(ya)蓋等處，不(bu)得有松動(dong)，連接(jie)裝置(zhi)必(bi)須可靠，尤其對(dui)大(da)功率的(de)(de)(de)電(dian)機(ji)(ji)(ji)(ji)，必(bi)須及(ji)時(shi)(shi)發現(xian)(xian)及(ji)時(shi)(shi)排除(chu)(chu)。噪(zao)聲和(he)異味是電(dian)機(ji)(ji)(ji)(ji)運(yun)行(xing)異常的(de)(de)(de)重要標(biao)志，也是重大(da)事故(gu)的(de)(de)(de)前兆(zhao)，必(bi)須及(ji)時(shi)(shi)發現(xian)(xian)，立即查明原因(yin)加以排除(chu)(chu)，否(fou)則延誤時(shi)(shi)機(ji)(ji)(ji)(ji)，擴大(da)故(gu)障(zhang)范(fan)圍，釀成燒(shao)毀(hui)電(dian)動(dong)機(ji)(ji)(ji)(ji)的(de)(de)(de)嚴重事故(gu)。