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)外觀：電(dian)(dian)(dian)動(dong)機(ji)表(biao)面油(you)漆層應(ying)(ying)光滑平整，銘牌安裝端正(zheng)，標志齊(qi)全(quan)；封閉式(shi)電(dian)(dian)(dian)動(dong)機(ji)座散熱(re)筋應(ying)(ying)完(wan)整無損，附件齊(qi)全(quan)；⑵手動(dong)旋轉：用(yong)(yong)手轉動(dong)電(dian)(dian)(dian)軸(zhou)、轉動(dong)應(ying)(ying)很靈活(huo)，慣(guan)動(dong)量較好(hao)，軸(zhou)向基本無竄動(dong)量；⑶診聽軸(zhou)承(cheng)(cheng)：通(tong)電(dian)(dian)(dian)運行(xing)15-25分鐘，軸(zhou)承(cheng)(cheng)應(ying)(ying)平穩輕快(kuai)，無停滯現象。聲音均勻和諧；軸(zhou)承(cheng)(cheng)溫度不高，沒有漏油(you)、甩油(you)現象；運行(xing)停止后，用(yong)(yong)手摸電(dian)(dian)(dian)動(dong)機(ji)座和端蓋不感到發熱(re)；⑷檢(jian)查接線(xian)(xian)：打開接線(xian)(xian)盒看(kan)各相(xiang)(xiang)相(xiang)(xiang)線(xian)(xian)標志是(shi)否(fou)(fou)清晰完(wan)整，聯絡片是(shi)否(fou)(fou)壓(ya)實壓(ya)緊，螺母是(shi)否(fou)(fou)齊(qi)全(quan)；⑸測(ce)量電(dian)(dian)(dian)阻：用(yong)(yong)額定(ding)電(dian)(dian)(dian)壓(ya)500V的(de)(de)手動(dong)式(shi)兆(zhao)歐(ou)表(biao)，測(ce)量出線(xian)(xian)端相(xiang)(xiang)線(xian)(xian)與相(xiang)(xiang)線(xian)(xian)之間及線(xian)(xian)對機(ji)座之間的(de)(de)絕緣(yuan)電(dian)(dian)(dian)阻，正(zheng)常電(dian)(dian)(dian)機(ji)的(de)(de)絕緣(yuan)電(dian)(dian)(dian)阻應(ying)(ying)大于1兆(zhao)歐(ou)。⑹測(ce)量電(dian)(dian)(dian)流(liu)(liu)。在運行(xing)中(zhong)用(yong)(yong)鉗型電(dian)(dian)(dian)流(liu)(liu)表(biao)測(ce)電(dian)(dian)(dian)機(ji)空載時各相(xiang)(xiang)的(de)(de)電(dian)(dian)(dian)流(liu)(liu)，三(san)相(xiang)(xiang)電(dian)(dian)(dian)流(liu)(liu)中(zhong)任(ren)何(he)一相(xiang)(xiang)與三(san)相(xiang)(xiang)平均值的(de)(de)偏(pian)差不得大于平均值的(de)(de)10%，空載電(dian)(dian)(dian)流(liu)(liu)一般為額定(ding)電(dian)(dian)(dian)流(liu)(liu)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)(qi)動(dong)設(she)備(bei)技(ji)術(shu)狀(zhuang)態(tai)(tai)完好(hao)(hao)，電(dian)(dian)動(dong)機(ji)啟(qi)(qi)動(dong)設(she)備(bei)技(ji)術(shu)狀(zhuang)態(tai)(tai)的(de)好(hao)(hao)壞直接(jie)(jie)關系(xi)到能否順(shun)利啟(qi)(qi)動(dong)。實踐表明，絕大(da)多數(shu)燒(shao)(shao)毀的(de)電(dian)(dian)動(dong)機(ji)都(dou)是啟(qi)(qi)動(dong)不順(shun)利而燒(shao)(shao)毀的(de)，如啟(qi)(qi)動(dong)設(she)備(bei)技(ji)術(shu)狀(zhuang)態(tai)(tai)不良引發(fa)(fa)的(de)缺相啟(qi)(qi)動(dong)；接(jie)(jie)觸(chu)器(qi)觸(chu)頭(tou)拉弧、打火而導致電(dian)(dian)壓、電(dian)(dian)流(liu)大(da)幅(fu)度(du)改(gai)變等。保持啟(qi)(qi)動(dong)設(she)備(bei)技(ji)術(shu)狀(zhuang)態(tai)(tai)良好(hao)(hao)的(de)措(cuo)施是：經常做檢查、清(qing)潔、緊(jin)固(gu)工作。若接(jie)(jie)觸(chu)器(qi)觸(chu)頭(tou)不清(qing)潔，氧(yang)化燒(shao)(shao)蝕嚴(yan)重(zhong)，則會(hui)產生(sheng)接(jie)(jie)觸(chu)電(dian)(dian)阻增(zeng)大(da)，引起發(fa)(fa)熱(re)、燒(shao)(shao)蝕觸(chu)點，從而形成缺相運行(xing)而燒(shao)(shao)毀電(dian)(dian)機(ji)繞組(zu)；接(jie)(jie)觸(chu)器(qi)吸(xi)合線圈(quan)鐵芯有銹蝕和灰(hui)塵(chen)，會(hui)使吸(xi)合不嚴(yan)而發(fa)(fa)出強烈噪聲，并增(zeng)大(da)線圈(quan)電(dian)(dian)流(liu)，直至(zhi)燒(shao)(shao)毀線圈(quan)。因此，電(dian)(dian)氣控制柜應設(she)在干燥、通風和便于操作的(de)位置(zhi)；還要定(ding)期除塵(chen)、清(qing)理觸(chu)點；線圈(quan)鐵芯要增(zeng)加防銹措(cuo)施；要經常緊(jin)固(gu)各連接(jie)(jie)部件；檢查接(jie)(jie)觸(chu)器(qi)觸(chu)點，保證接(jie)(jie)觸(chu)良好(hao)(hao)，機(ji)構動(dong)作應靈活、準(zhun)確，這些(xie)是保證啟(qi)(qi)動(dong)順(shun)利的(de)必然條件。

2、保(bao)持電(dian)動機清(qing)(qing)潔(jie)和良好的冷卻環境，在電(dian)動機的進風口處，必(bi)須經(jing)常(chang)保(bao)持清(qing)(qing)潔(jie)。進風口的周圍不得有(you)塵土、油污、水漬和其它秸稈雜物，以防止這類東西(xi)吸入電(dian)機內部，形成短路介(jie)質(zhi)或損傷(shang)電(dian)機繞組絕(jue)緣層；或阻斷電(dian)機的通風冷卻而溫度(du)升高(gao)，導致燒毀。

3、保持電(dian)(dian)動機(ji)(ji)在額定電(dian)(dian)流(liu)(liu)(liu)下工作(zuo)，避免農用(yong)電(dian)(dian)動機(ji)(ji)的(de)(de)過(guo)載運(yun)(yun)(yun)行。當電(dian)(dian)動機(ji)(ji)處于過(guo)載狀態運(yun)(yun)(yun)行時(shi)，電(dian)(dian)動機(ji)(ji)轉(zhuan)速下降，電(dian)(dian)流(liu)(liu)(liu)增大，溫(wen)度(du)升(sheng)高，繞組(zu)線(xian)圈(quan)過(guo)熱。其主(zhu)要(yao)原(yuan)因是(shi)拖(tuo)動負(fu)(fu)荷(he)過(guo)大，電(dian)(dian)壓(ya)過(guo)低或被(bei)拖(tuo)動的(de)(de)機(ji)(ji)械卡滯(zhi)等造成(cheng)的(de)(de)；若過(guo)載時(shi)間稍長，過(guo)載電(dian)(dian)機(ji)(ji)從電(dian)(dian)網中吸收大量有功功率，電(dian)(dian)流(liu)(liu)(liu)便急(ji)劇增加，隨(sui)之溫(wen)度(du)上升(sheng)。在高溫(wen)下運(yun)(yun)(yun)行的(de)(de)電(dian)(dian)機(ji)(ji)，絕(jue)緣材料易老化(hua)失效而(er)燒毀(hui)繞組(zu)線(xian)圈(quan)，這(zhe)是(shi)燒毀(hui)電(dian)(dian)機(ji)(ji)的(de)(de)主(zhu)要(yao)原(yuan)因。因此，一要(yao)經常(chang)注(zhu)意(yi)檢(jian)查機(ji)(ji)組(zu)傳動裝置是(shi)否(fou)運(yun)(yun)(yun)轉(zhuan)靈活、可靠(kao)，隨(sui)時(shi)檢(jian)查、調整傳動皮帶松緊度(du)，防止卡滯(zhi)；二要(yao)注(zhu)意(yi)作(zuo)業機(ji)(ji)械不(bu)(bu)要(yao)較長時(shi)間超負(fu)(fu)荷(he)工作(zuo)；三(san)要(yao)保持電(dian)(dian)壓(ya)穩定，尤(you)其不(bu)(bu)得低壓(ya)運(yun)(yun)(yun)轉(zhuan)，從而(er)確保電(dian)(dian)動機(ji)(ji)在額定電(dian)(dian)流(liu)(liu)(liu)下正常(chang)工作(zuo)。

4、保(bao)持(chi)相間電(dian)(dian)流平衡。農用三相異步電(dian)(dian)動(dong)機(ji)(ji)，其中任何(he)一(yi)相的(de)電(dian)(dian)流值(zhi)與其他(ta)兩相電(dian)(dian)流平均值(zhi)之差(cha)不得超(chao)過10%，這(zhe)(zhe)是保(bao)證電(dian)(dian)動(dong)機(ji)(ji)安全運轉的(de)必要條件。如(ru)果這(zhe)(zhe)個差(cha)值(zhi)超(chao)過10%，則表明(ming)電(dian)(dian)動(dong)機(ji)(ji)已(yi)經出現故(gu)障，必須立即(ji)停機(ji)(ji)查明(ming)原因，并(bing)排除故(gu)障后(hou)方能(neng)繼續(xu)工作，否則故(gu)障會(hui)迅速(su)擴(kuo)大，直至燒(shao)毀電(dian)(dian)動(dong)機(ji)(ji)。

5、保(bao)持電(dian)動(dong)機(ji)(ji)(ji)(ji)溫(wen)(wen)度(du)(du)和溫(wen)(wen)升(sheng)(sheng)在(zai)(zai)正常范圍內(nei)。電(dian)機(ji)(ji)(ji)(ji)運行(xing)中，要隨時(shi)檢查軸(zhou)(zhou)(zhou)承(cheng)(cheng)、定(ding)子(zi)、外殼(ke)等(deng)部位(wei)的(de)溫(wen)(wen)度(du)(du)有(you)無(wu)異常，特別是對沒有(you)過載保(bao)護的(de)電(dian)動(dong)機(ji)(ji)(ji)(ji)，監(jian)視溫(wen)(wen)度(du)(du)更(geng)為重(zhong)要。如(ru)軸(zhou)(zhou)(zhou)承(cheng)(cheng)缺油(you)或損壞(huai)(huai)，則必(bi)然(ran)引(yin)起溫(wen)(wen)度(du)(du)升(sheng)(sheng)高(gao)(gao)。在(zai)(zai)軸(zhou)(zhou)(zhou)承(cheng)(cheng)附(fu)近機(ji)(ji)(ji)(ji)體(ti)(ti)溫(wen)(wen)度(du)(du)升(sheng)(sheng)高(gao)(gao)，就要立即停(ting)機(ji)(ji)(ji)(ji)檢查軸(zhou)(zhou)(zhou)承(cheng)(cheng)，可先加油(you)，若仍然(ran)無(wu)效，則應拆下軸(zhou)(zhou)(zhou)承(cheng)(cheng)鑒定(ding)。若滾動(dong)體(ti)(ti)、滾道表面有(you)裂紋、劃傷或損壞(huai)(huai)，或間隙變大，內(nei)環在(zai)(zai)軸(zhou)(zhou)(zhou)承(cheng)(cheng)上有(you)轉動(dong)，出現任何一(yi)項(xiang)，都(dou)應更(geng)換(huan)軸(zhou)(zhou)(zhou)承(cheng)(cheng)。否則繼(ji)續使(shi)用(yong)會(hui)使(shi)軸(zhou)(zhou)(zhou)承(cheng)(cheng)進一(yi)步損壞(huai)(huai)，導致塌架、電(dian)機(ji)(ji)(ji)(ji)掃膛燒毀等(deng)重(zhong)大事故。監(jian)測電(dian)動(dong)機(ji)(ji)(ji)(ji)的(de)溫(wen)(wen)度(du)(du)或溫(wen)(wen)升(sheng)(sheng)有(you)無(wu)變化(hua)，可用(yong)下述簡(jian)單方法監(jian)視：在(zai)(zai)電(dian)動(dong)機(ji)(ji)(ji)(ji)的(de)孔(kong)內(nei)，插支溫(wen)(wen)度(du)(du)計，用(yong)棉花團塞(sai)緊(jin)固定(ding)，便(bian)可隨時(shi)監(jian)視電(dian)動(dong)機(ji)(ji)(ji)(ji)溫(wen)(wen)度(du)(du)的(de)變化(hua)，機(ji)(ji)(ji)(ji)外與殼(ke)內(nei)溫(wen)(wen)差通常為1℃。

6、及時發現(xian)(xian)和處理電(dian)(dian)機(ji)(ji)異常(chang)，電(dian)(dian)動(dong)(dong)機(ji)(ji)運(yun)行中(zhong)應(ying)沒有(you)振(zhen)動(dong)(dong)、噪聲和異味。若出現(xian)(xian)振(zhen)動(dong)(dong)，則(ze)(ze)會引起(qi)電(dian)(dian)動(dong)(dong)機(ji)(ji)相連(lian)接的負(fu)載作機(ji)(ji)的軸(zhou)心(xin)(xin)不同心(xin)(xin)度的增大，進而負(fu)荷增大，負(fu)荷電(dian)(dian)流也(ye)(ye)隨之增大，導致溫度升高而燒毀電(dian)(dian)機(ji)(ji)。因(yin)此，要經常(chang)檢查引起(qi)振(zhen)動(dong)(dong)的地腳螺(luo)栓、電(dian)(dian)動(dong)(dong)機(ji)(ji)端蓋、軸(zhou)承壓蓋等處，不得有(you)松(song)動(dong)(dong)，連(lian)接裝置必須可靠，尤其對大功率的電(dian)(dian)機(ji)(ji)，必須及時發現(xian)(xian)及時排(pai)除(chu)。噪聲和異味是電(dian)(dian)機(ji)(ji)運(yun)行異常(chang)的重(zhong)要標(biao)志，也(ye)(ye)是重(zhong)大事故(gu)的前(qian)兆，必須及時發現(xian)(xian)，立即查明原因(yin)加以排(pai)除(chu)，否(fou)則(ze)(ze)延(yan)誤時機(ji)(ji)，擴大故(gu)障范圍，釀成燒毀電(dian)(dian)動(dong)(dong)機(ji)(ji)的嚴重(zhong)事故(gu)。