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)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)表(biao)(biao)面油(you)漆層應(ying)(ying)光滑平(ping)整(zheng)，銘牌安裝(zhuang)端正，標(biao)志齊(qi)全(quan)(quan)；封(feng)閉(bi)式電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)座(zuo)散熱筋應(ying)(ying)完整(zheng)無損，附件齊(qi)全(quan)(quan)；⑵手(shou)動(dong)(dong)旋轉(zhuan)：用(yong)手(shou)轉(zhuan)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)軸、轉(zhuan)動(dong)(dong)應(ying)(ying)很(hen)靈活(huo)，慣(guan)動(dong)(dong)量(liang)(liang)較好，軸向基本無竄(cuan)動(dong)(dong)量(liang)(liang)；⑶診聽軸承：通電(dian)(dian)(dian)(dian)(dian)(dian)運(yun)行(xing)15-25分鐘(zhong)，軸承應(ying)(ying)平(ping)穩輕(qing)快，無停滯現(xian)象。聲音均(jun)勻和諧；軸承溫(wen)度不高，沒(mei)有漏油(you)、甩油(you)現(xian)象；運(yun)行(xing)停止后，用(yong)手(shou)摸電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)座(zuo)和端蓋不感到發熱；⑷檢查(cha)接線(xian)(xian)：打開接線(xian)(xian)盒看各(ge)(ge)相(xiang)相(xiang)線(xian)(xian)標(biao)志是否(fou)清晰完整(zheng)，聯絡片是否(fou)壓(ya)實壓(ya)緊，螺母(mu)是否(fou)齊(qi)全(quan)(quan)；⑸測量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)阻：用(yong)額(e)定電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)500V的(de)(de)(de)手(shou)動(dong)(dong)式兆歐表(biao)(biao)，測量(liang)(liang)出線(xian)(xian)端相(xiang)線(xian)(xian)與(yu)相(xiang)線(xian)(xian)之(zhi)間(jian)及線(xian)(xian)對機(ji)(ji)(ji)座(zuo)之(zhi)間(jian)的(de)(de)(de)絕緣電(dian)(dian)(dian)(dian)(dian)(dian)阻，正常電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)的(de)(de)(de)絕緣電(dian)(dian)(dian)(dian)(dian)(dian)阻應(ying)(ying)大(da)于1兆歐。⑹測量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)流。在運(yun)行(xing)中用(yong)鉗型電(dian)(dian)(dian)(dian)(dian)(dian)流表(biao)(biao)測電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)空(kong)載時各(ge)(ge)相(xiang)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流，三相(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)流中任何一相(xiang)與(yu)三相(xiang)平(ping)均(jun)值(zhi)的(de)(de)(de)偏差(cha)不得大(da)于平(ping)均(jun)值(zhi)的(de)(de)(de)10%，空(kong)載電(dian)(dian)(dian)(dian)(dian)(dian)流一般為額(e)定電(dian)(dian)(dian)(dian)(dian)(dian)流的(de)(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(dong)設(she)(she)備技術(shu)狀(zhuang)(zhuang)態(tai)(tai)完好(hao)(hao)，電(dian)動(dong)機啟(qi)動(dong)設(she)(she)備技術(shu)狀(zhuang)(zhuang)態(tai)(tai)的(de)好(hao)(hao)壞直接(jie)關系到能否順利啟(qi)動(dong)。實(shi)踐表明，絕大(da)多數燒(shao)毀(hui)的(de)電(dian)動(dong)機都是(shi)啟(qi)動(dong)不(bu)(bu)順利而燒(shao)毀(hui)的(de)，如啟(qi)動(dong)設(she)(she)備技術(shu)狀(zhuang)(zhuang)態(tai)(tai)不(bu)(bu)良(liang)引(yin)發(fa)的(de)缺(que)相(xiang)啟(qi)動(dong)；接(jie)觸(chu)(chu)(chu)(chu)器觸(chu)(chu)(chu)(chu)頭拉弧、打火而導(dao)致(zhi)電(dian)壓、電(dian)流(liu)大(da)幅(fu)度改變等。保(bao)持(chi)啟(qi)動(dong)設(she)(she)備技術(shu)狀(zhuang)(zhuang)態(tai)(tai)良(liang)好(hao)(hao)的(de)措施是(shi)：經常(chang)做檢查、清(qing)潔、緊固工作(zuo)。若接(jie)觸(chu)(chu)(chu)(chu)器觸(chu)(chu)(chu)(chu)頭不(bu)(bu)清(qing)潔，氧化燒(shao)蝕嚴(yan)重，則會產生(sheng)接(jie)觸(chu)(chu)(chu)(chu)電(dian)阻增(zeng)大(da)，引(yin)起(qi)發(fa)熱、燒(shao)蝕觸(chu)(chu)(chu)(chu)點(dian)，從而形(xing)成(cheng)缺(que)相(xiang)運行(xing)而燒(shao)毀(hui)電(dian)機繞組；接(jie)觸(chu)(chu)(chu)(chu)器吸(xi)合線(xian)圈(quan)(quan)鐵(tie)芯有(you)銹(xiu)蝕和(he)灰塵，會使(shi)吸(xi)合不(bu)(bu)嚴(yan)而發(fa)出(chu)強烈噪聲，并增(zeng)大(da)線(xian)圈(quan)(quan)電(dian)流(liu)，直至燒(shao)毀(hui)線(xian)圈(quan)(quan)。因此，電(dian)氣(qi)控制柜(ju)應(ying)設(she)(she)在干燥、通風和(he)便(bian)于操作(zuo)的(de)位(wei)置；還要(yao)(yao)定(ding)期除塵、清(qing)理(li)觸(chu)(chu)(chu)(chu)點(dian)；線(xian)圈(quan)(quan)鐵(tie)芯要(yao)(yao)增(zeng)加(jia)防銹(xiu)措施；要(yao)(yao)經常(chang)緊固各連接(jie)部件(jian)；檢查接(jie)觸(chu)(chu)(chu)(chu)器觸(chu)(chu)(chu)(chu)點(dian)，保(bao)證接(jie)觸(chu)(chu)(chu)(chu)良(liang)好(hao)(hao)，機構動(dong)作(zuo)應(ying)靈活、準(zhun)確，這些(xie)是(shi)保(bao)證啟(qi)動(dong)順利的(de)必(bi)然條件(jian)。

2、保(bao)(bao)持(chi)電(dian)(dian)動(dong)(dong)機清(qing)潔和良好的(de)(de)冷(leng)卻(que)環境，在電(dian)(dian)動(dong)(dong)機的(de)(de)進風(feng)口處，必須(xu)經常(chang)保(bao)(bao)持(chi)清(qing)潔。進風(feng)口的(de)(de)周圍不(bu)得有(you)塵土、油污、水漬和其它(ta)秸稈(gan)雜物，以防止(zhi)這類東西吸(xi)入電(dian)(dian)機內部，形成短路介質或損傷(shang)電(dian)(dian)機繞組絕緣層；或阻(zu)斷(duan)電(dian)(dian)機的(de)(de)通(tong)風(feng)冷(leng)卻(que)而溫度升高(gao)，導(dao)致燒毀。

3、保持電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)在額定電(dian)(dian)(dian)(dian)(dian)流(liu)下工(gong)作，避免農(nong)用電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)的(de)過(guo)(guo)載運(yun)行。當電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)處于(yu)過(guo)(guo)載狀態(tai)運(yun)行時，電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)轉速(su)下降，電(dian)(dian)(dian)(dian)(dian)流(liu)增(zeng)大(da)，溫(wen)(wen)度升高，繞(rao)組(zu)(zu)線圈過(guo)(guo)熱。其主要(yao)(yao)原(yuan)因是拖(tuo)動(dong)(dong)負(fu)荷過(guo)(guo)大(da)，電(dian)(dian)(dian)(dian)(dian)壓(ya)過(guo)(guo)低或(huo)被拖(tuo)動(dong)(dong)的(de)機(ji)(ji)械(xie)卡滯(zhi)等造成(cheng)的(de)；若過(guo)(guo)載時間稍長，過(guo)(guo)載電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)從電(dian)(dian)(dian)(dian)(dian)網中吸收大(da)量有功功率，電(dian)(dian)(dian)(dian)(dian)流(liu)便(bian)急(ji)劇增(zeng)加，隨(sui)之溫(wen)(wen)度上(shang)升。在高溫(wen)(wen)下運(yun)行的(de)電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)，絕緣材料易老化失效(xiao)而燒毀繞(rao)組(zu)(zu)線圈，這(zhe)是燒毀電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)的(de)主要(yao)(yao)原(yuan)因。因此，一要(yao)(yao)經常(chang)注(zhu)意檢查機(ji)(ji)組(zu)(zu)傳(chuan)動(dong)(dong)裝置是否運(yun)轉靈(ling)活、可靠，隨(sui)時檢查、調整傳(chuan)動(dong)(dong)皮帶松(song)緊度，防止卡滯(zhi)；二要(yao)(yao)注(zhu)意作業(ye)機(ji)(ji)械(xie)不要(yao)(yao)較長時間超負(fu)荷工(gong)作；三要(yao)(yao)保持電(dian)(dian)(dian)(dian)(dian)壓(ya)穩定，尤其不得低壓(ya)運(yun)轉，從而確保電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)在額定電(dian)(dian)(dian)(dian)(dian)流(liu)下正常(chang)工(gong)作。

4、保(bao)持相間電(dian)(dian)流(liu)平衡(heng)。農用三相異步電(dian)(dian)動(dong)機(ji)，其中任何一相的(de)(de)電(dian)(dian)流(liu)值與其他兩(liang)相電(dian)(dian)流(liu)平均值之差(cha)不得超(chao)過10%，這是(shi)保(bao)證電(dian)(dian)動(dong)機(ji)安全(quan)運轉的(de)(de)必要(yao)條件(jian)。如果(guo)這個差(cha)值超(chao)過10%，則(ze)表明電(dian)(dian)動(dong)機(ji)已經出現故(gu)障(zhang)(zhang)，必須立即停機(ji)查明原因，并排除故(gu)障(zhang)(zhang)后(hou)方能(neng)繼續(xu)工作(zuo)，否則(ze)故(gu)障(zhang)(zhang)會迅速擴大，直至燒毀電(dian)(dian)動(dong)機(ji)。

5、保(bao)持電動(dong)機(ji)(ji)溫(wen)(wen)(wen)度和溫(wen)(wen)(wen)升在正常范圍內(nei)。電機(ji)(ji)運行中，要隨時(shi)檢查軸(zhou)承(cheng)(cheng)、定(ding)(ding)子、外殼(ke)(ke)等部(bu)位(wei)的溫(wen)(wen)(wen)度有(you)(you)無(wu)異常，特(te)別是(shi)對(dui)沒(mei)有(you)(you)過載(zai)保(bao)護的電動(dong)機(ji)(ji)，監視溫(wen)(wen)(wen)度更為重要。如軸(zhou)承(cheng)(cheng)缺油或損壞，則(ze)必然引起溫(wen)(wen)(wen)度升高。在軸(zhou)承(cheng)(cheng)附近機(ji)(ji)體(ti)溫(wen)(wen)(wen)度升高，就(jiu)要立即(ji)停機(ji)(ji)檢查軸(zhou)承(cheng)(cheng)，可先加油，若仍(reng)然無(wu)效(xiao)，則(ze)應拆下(xia)軸(zhou)承(cheng)(cheng)鑒定(ding)(ding)。若滾(gun)動(dong)體(ti)、滾(gun)道表面(mian)有(you)(you)裂紋、劃傷(shang)或損壞，或間隙變大，內(nei)環(huan)在軸(zhou)承(cheng)(cheng)上(shang)有(you)(you)轉動(dong)，出現任何一項，都應更換軸(zhou)承(cheng)(cheng)。否則(ze)繼續使用(yong)會使軸(zhou)承(cheng)(cheng)進一步損壞，導致塌架、電機(ji)(ji)掃膛燒毀等重大事故(gu)。監測(ce)電動(dong)機(ji)(ji)的溫(wen)(wen)(wen)度或溫(wen)(wen)(wen)升有(you)(you)無(wu)變化，可用(yong)下(xia)述簡單方法監視：在電動(dong)機(ji)(ji)的孔內(nei)，插支(zhi)溫(wen)(wen)(wen)度計，用(yong)棉(mian)花(hua)團塞緊固定(ding)(ding)，便可隨時(shi)監視電動(dong)機(ji)(ji)溫(wen)(wen)(wen)度的變化，機(ji)(ji)外與殼(ke)(ke)內(nei)溫(wen)(wen)(wen)差通常為1℃。

6、及(ji)時(shi)發(fa)(fa)現(xian)和(he)處(chu)理電(dian)(dian)機(ji)(ji)(ji)異常(chang)，電(dian)(dian)動(dong)機(ji)(ji)(ji)運(yun)行中應沒有振(zhen)動(dong)、噪(zao)聲和(he)異味。若出現(xian)振(zhen)動(dong)，則(ze)會(hui)引起電(dian)(dian)動(dong)機(ji)(ji)(ji)相(xiang)連接的(de)(de)負載(zai)作(zuo)機(ji)(ji)(ji)的(de)(de)軸(zhou)心(xin)不(bu)同心(xin)度的(de)(de)增(zeng)大，進而負荷增(zeng)大，負荷電(dian)(dian)流也隨之增(zeng)大，導致溫度升高而燒毀(hui)電(dian)(dian)機(ji)(ji)(ji)。因此，要經常(chang)檢查引起振(zhen)動(dong)的(de)(de)地腳(jiao)螺栓、電(dian)(dian)動(dong)機(ji)(ji)(ji)端蓋、軸(zhou)承壓(ya)蓋等處(chu)，不(bu)得有松動(dong)，連接裝置(zhi)必(bi)須(xu)可靠，尤其對大功率的(de)(de)電(dian)(dian)機(ji)(ji)(ji)，必(bi)須(xu)及(ji)時(shi)發(fa)(fa)現(xian)及(ji)時(shi)排除(chu)。噪(zao)聲和(he)異味是(shi)電(dian)(dian)機(ji)(ji)(ji)運(yun)行異常(chang)的(de)(de)重要標志，也是(shi)重大事故(gu)的(de)(de)前兆，必(bi)須(xu)及(ji)時(shi)發(fa)(fa)現(xian)，立即查明原因加以排除(chu)，否則(ze)延誤時(shi)機(ji)(ji)(ji)，擴大故(gu)障范圍，釀成燒毀(hui)電(dian)(dian)動(dong)機(ji)(ji)(ji)的(de)(de)嚴(yan)重事故(gu)。