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查看外觀：電(dian)動(dong)(dong)機(ji)表面油(you)漆層應(ying)(ying)光滑平(ping)(ping)整(zheng)，銘(ming)牌安(an)裝端(duan)(duan)正(zheng)，標(biao)志齊(qi)全(quan)；封閉式(shi)電(dian)動(dong)(dong)機(ji)座(zuo)散熱筋應(ying)(ying)完整(zheng)無(wu)損，附件齊(qi)全(quan)；⑵手(shou)動(dong)(dong)旋轉：用(yong)(yong)手(shou)轉動(dong)(dong)電(dian)軸(zhou)、轉動(dong)(dong)應(ying)(ying)很靈活(huo)，慣動(dong)(dong)量(liang)(liang)較好(hao)，軸(zhou)向(xiang)基本無(wu)竄動(dong)(dong)量(liang)(liang)；⑶診聽軸(zhou)承(cheng)(cheng)：通電(dian)運行15-25分鐘，軸(zhou)承(cheng)(cheng)應(ying)(ying)平(ping)(ping)穩輕快，無(wu)停(ting)滯現象。聲音均勻和(he)諧；軸(zhou)承(cheng)(cheng)溫(wen)度不(bu)高，沒有漏油(you)、甩油(you)現象；運行停(ting)止后，用(yong)(yong)手(shou)摸(mo)電(dian)動(dong)(dong)機(ji)座(zuo)和(he)端(duan)(duan)蓋不(bu)感到發(fa)熱；⑷檢查接線(xian)(xian)(xian)：打(da)開接線(xian)(xian)(xian)盒看各(ge)相(xiang)(xiang)相(xiang)(xiang)線(xian)(xian)(xian)標(biao)志是否清晰完整(zheng)，聯(lian)絡片是否壓實壓緊，螺母是否齊(qi)全(quan)；⑸測(ce)量(liang)(liang)電(dian)阻(zu)：用(yong)(yong)額(e)定電(dian)壓500V的(de)手(shou)動(dong)(dong)式(shi)兆歐表，測(ce)量(liang)(liang)出線(xian)(xian)(xian)端(duan)(duan)相(xiang)(xiang)線(xian)(xian)(xian)與(yu)相(xiang)(xiang)線(xian)(xian)(xian)之間(jian)及線(xian)(xian)(xian)對機(ji)座(zuo)之間(jian)的(de)絕緣電(dian)阻(zu)，正(zheng)常電(dian)機(ji)的(de)絕緣電(dian)阻(zu)應(ying)(ying)大于1兆歐。⑹測(ce)量(liang)(liang)電(dian)流。在(zai)運行中用(yong)(yong)鉗型電(dian)流表測(ce)電(dian)機(ji)空載時各(ge)相(xiang)(xiang)的(de)電(dian)流，三相(xiang)(xiang)電(dian)流中任何一(yi)相(xiang)(xiang)與(yu)三相(xiang)(xiang)平(ping)(ping)均值的(de)偏差不(bu)得大于平(ping)(ping)均值的(de)10%，空載電(dian)流一(yi)般(ban)為額(e)定電(dian)流的(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)(qi)(qi)(qi)動(dong)設備技術狀(zhuang)(zhuang)態完好(hao)，電動(dong)機(ji)啟(qi)(qi)(qi)(qi)動(dong)設備技術狀(zhuang)(zhuang)態的(de)(de)好(hao)壞(huai)直接(jie)(jie)關系到(dao)能否順(shun)利(li)啟(qi)(qi)(qi)(qi)動(dong)。實踐表明(ming)，絕大(da)多數燒毀(hui)的(de)(de)電動(dong)機(ji)都是啟(qi)(qi)(qi)(qi)動(dong)不(bu)(bu)順(shun)利(li)而(er)燒毀(hui)的(de)(de)，如(ru)啟(qi)(qi)(qi)(qi)動(dong)設備技術狀(zhuang)(zhuang)態不(bu)(bu)良(liang)引發的(de)(de)缺(que)(que)相啟(qi)(qi)(qi)(qi)動(dong)；接(jie)(jie)觸(chu)(chu)器(qi)觸(chu)(chu)頭拉弧、打(da)火而(er)導致電壓、電流(liu)大(da)幅度改變等。保(bao)持(chi)啟(qi)(qi)(qi)(qi)動(dong)設備技術狀(zhuang)(zhuang)態良(liang)好(hao)的(de)(de)措(cuo)施是：經常做檢(jian)查(cha)、清潔、緊固工作(zuo)。若接(jie)(jie)觸(chu)(chu)器(qi)觸(chu)(chu)頭不(bu)(bu)清潔，氧化燒蝕嚴(yan)重，則會產生接(jie)(jie)觸(chu)(chu)電阻增大(da)，引起發熱、燒蝕觸(chu)(chu)點，從而(er)形成缺(que)(que)相運行而(er)燒毀(hui)電機(ji)繞組(zu)；接(jie)(jie)觸(chu)(chu)器(qi)吸合線圈(quan)鐵(tie)芯有(you)銹蝕和(he)(he)灰塵(chen)，會使(shi)吸合不(bu)(bu)嚴(yan)而(er)發出強烈噪聲，并增大(da)線圈(quan)電流(liu)，直至燒毀(hui)線圈(quan)。因此，電氣控制柜應設在干燥、通風和(he)(he)便于操作(zuo)的(de)(de)位置；還要定期除塵(chen)、清理觸(chu)(chu)點；線圈(quan)鐵(tie)芯要增加防銹措(cuo)施；要經常緊固各連(lian)接(jie)(jie)部(bu)件(jian)；檢(jian)查(cha)接(jie)(jie)觸(chu)(chu)器(qi)觸(chu)(chu)點，保(bao)證(zheng)接(jie)(jie)觸(chu)(chu)良(liang)好(hao)，機(ji)構動(dong)作(zuo)應靈活(huo)、準確，這些是保(bao)證(zheng)啟(qi)(qi)(qi)(qi)動(dong)順(shun)利(li)的(de)(de)必然條件(jian)。

2、保持(chi)電(dian)動(dong)機(ji)清潔(jie)和良好(hao)的冷(leng)卻環境，在電(dian)動(dong)機(ji)的進風(feng)口處，必須(xu)經常保持(chi)清潔(jie)。進風(feng)口的周圍(wei)不得(de)有塵土、油污、水漬和其(qi)它秸稈雜物，以防(fang)止這類東西吸入電(dian)機(ji)內部，形成(cheng)短(duan)路(lu)介(jie)質或損傷(shang)電(dian)機(ji)繞組絕(jue)緣層；或阻斷電(dian)機(ji)的通(tong)風(feng)冷(leng)卻而溫(wen)度升(sheng)高，導(dao)致燒毀。

3、保持電(dian)動(dong)機(ji)(ji)在額定電(dian)流下工作，避(bi)免(mian)農用電(dian)動(dong)機(ji)(ji)的(de)(de)(de)過(guo)載(zai)(zai)運(yun)行(xing)。當電(dian)動(dong)機(ji)(ji)處(chu)于過(guo)載(zai)(zai)狀態(tai)運(yun)行(xing)時，電(dian)動(dong)機(ji)(ji)轉(zhuan)速下降，電(dian)流增大，溫(wen)度升高，繞組(zu)線圈過(guo)熱。其(qi)主(zhu)要原因是(shi)拖(tuo)動(dong)負(fu)荷(he)過(guo)大，電(dian)壓過(guo)低(di)或被拖(tuo)動(dong)的(de)(de)(de)機(ji)(ji)械卡(ka)滯等造(zao)成的(de)(de)(de)；若過(guo)載(zai)(zai)時間稍(shao)長(chang)，過(guo)載(zai)(zai)電(dian)機(ji)(ji)從(cong)電(dian)網(wang)中吸收大量(liang)有(you)功(gong)(gong)功(gong)(gong)率，電(dian)流便急(ji)劇增加，隨之溫(wen)度上(shang)升。在高溫(wen)下運(yun)行(xing)的(de)(de)(de)電(dian)機(ji)(ji)，絕(jue)緣材料易老(lao)化(hua)失(shi)效而(er)燒毀(hui)繞組(zu)線圈，這(zhe)是(shi)燒毀(hui)電(dian)機(ji)(ji)的(de)(de)(de)主(zhu)要原因。因此，一要經常注意(yi)檢(jian)查(cha)(cha)機(ji)(ji)組(zu)傳(chuan)(chuan)動(dong)裝置是(shi)否運(yun)轉(zhuan)靈活、可靠(kao)，隨時檢(jian)查(cha)(cha)、調整傳(chuan)(chuan)動(dong)皮(pi)帶松緊度，防止卡(ka)滯；二(er)要注意(yi)作業機(ji)(ji)械不要較長(chang)時間超負(fu)荷(he)工作；三要保持電(dian)壓穩定，尤其(qi)不得低(di)壓運(yun)轉(zhuan)，從(cong)而(er)確保電(dian)動(dong)機(ji)(ji)在額定電(dian)流下正常工作。

4、保(bao)(bao)持相(xiang)間電(dian)流(liu)(liu)平(ping)衡(heng)。農用(yong)三相(xiang)異步(bu)電(dian)動(dong)機，其中任何一相(xiang)的電(dian)流(liu)(liu)值(zhi)(zhi)與其他(ta)兩相(xiang)電(dian)流(liu)(liu)平(ping)均值(zhi)(zhi)之差不得超(chao)過(guo)10%，這是保(bao)(bao)證電(dian)動(dong)機安全運(yun)轉(zhuan)的必(bi)要條件(jian)。如果這個差值(zhi)(zhi)超(chao)過(guo)10%，則表(biao)明(ming)電(dian)動(dong)機已經出現故障(zhang)，必(bi)須立即停(ting)機查明(ming)原因，并(bing)排除故障(zhang)后方能(neng)繼續(xu)工作(zuo)，否則故障(zhang)會迅速擴大(da)，直至燒(shao)毀電(dian)動(dong)機。

5、保(bao)持(chi)電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)溫(wen)(wen)(wen)(wen)度(du)(du)和(he)溫(wen)(wen)(wen)(wen)升(sheng)在正常(chang)(chang)范圍內(nei)。電(dian)(dian)機(ji)(ji)(ji)運行中，要隨(sui)(sui)時檢查軸承(cheng)、定子、外殼等(deng)部位的(de)溫(wen)(wen)(wen)(wen)度(du)(du)有(you)(you)無(wu)異常(chang)(chang)，特別(bie)是對沒有(you)(you)過(guo)載保(bao)護的(de)電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)，監(jian)視溫(wen)(wen)(wen)(wen)度(du)(du)更為重(zhong)(zhong)要。如軸承(cheng)缺(que)油或(huo)損壞(huai)，則必然引(yin)起溫(wen)(wen)(wen)(wen)度(du)(du)升(sheng)高。在軸承(cheng)附近(jin)機(ji)(ji)(ji)體溫(wen)(wen)(wen)(wen)度(du)(du)升(sheng)高，就要立即停機(ji)(ji)(ji)檢查軸承(cheng)，可(ke)先(xian)加油，若仍(reng)然無(wu)效，則應(ying)拆(chai)下(xia)軸承(cheng)鑒定。若滾(gun)動(dong)(dong)體、滾(gun)道表面有(you)(you)裂紋、劃傷(shang)或(huo)損壞(huai)，或(huo)間隙(xi)變(bian)大，內(nei)環在軸承(cheng)上有(you)(you)轉動(dong)(dong)，出現任何(he)一(yi)項，都應(ying)更換軸承(cheng)。否則繼續使用(yong)會使軸承(cheng)進一(yi)步損壞(huai)，導致塌架、電(dian)(dian)機(ji)(ji)(ji)掃膛燒毀等(deng)重(zhong)(zhong)大事故。監(jian)測(ce)電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)的(de)溫(wen)(wen)(wen)(wen)度(du)(du)或(huo)溫(wen)(wen)(wen)(wen)升(sheng)有(you)(you)無(wu)變(bian)化(hua)，可(ke)用(yong)下(xia)述簡(jian)單方(fang)法監(jian)視：在電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)的(de)孔內(nei)，插支(zhi)溫(wen)(wen)(wen)(wen)度(du)(du)計，用(yong)棉花團塞緊固(gu)定，便可(ke)隨(sui)(sui)時監(jian)視電(dian)(dian)動(dong)(dong)機(ji)(ji)(ji)溫(wen)(wen)(wen)(wen)度(du)(du)的(de)變(bian)化(hua)，機(ji)(ji)(ji)外與殼內(nei)溫(wen)(wen)(wen)(wen)差通常(chang)(chang)為1℃。

6、及時(shi)發現和處理電(dian)機(ji)異常(chang)(chang)(chang)，電(dian)動機(ji)運行(xing)中應沒有振動、噪(zao)(zao)聲和異味。若出現振動，則會引起電(dian)動機(ji)相連(lian)接的負載作機(ji)的軸心不同(tong)心度(du)的增(zeng)大(da)，進而(er)負荷(he)增(zeng)大(da)，負荷(he)電(dian)流也隨之增(zeng)大(da)，導致溫度(du)升(sheng)高而(er)燒(shao)(shao)毀電(dian)機(ji)。因此，要(yao)經常(chang)(chang)(chang)檢查引起振動的地(di)腳螺(luo)栓(shuan)、電(dian)動機(ji)端蓋、軸承壓蓋等(deng)處，不得有松動，連(lian)接裝置必(bi)須(xu)可靠，尤其(qi)對大(da)功率(lv)的電(dian)機(ji)，必(bi)須(xu)及時(shi)發現及時(shi)排(pai)除。噪(zao)(zao)聲和異味是(shi)(shi)電(dian)機(ji)運行(xing)異常(chang)(chang)(chang)的重要(yao)標志，也是(shi)(shi)重大(da)事故的前兆，必(bi)須(xu)及時(shi)發現，立即(ji)查明原因加(jia)以排(pai)除，否則延誤時(shi)機(ji)，擴大(da)故障范圍，釀成燒(shao)(shao)毀電(dian)動機(ji)的嚴重事故。