電動機正常運行(xing)時溫(wen)(wen)升(sheng)(sheng)穩(wen)定，并在規(gui)定的溫(wen)(wen)升(sheng)(sheng)允(yun)許(xu)范圍(wei)內(nei)。如果溫(wen)(wen)升(sheng)(sheng)過高(gao)，或(huo)與在同樣工作條件下(xia)的同類電動機相比，溫(wen)(wen)度明顯(xian)偏高(gao)，就應視為故障了。
電(dian)(dian)(dian)動機運行時(shi)溫(wen)升(sheng)過(guo)高，不僅(jin)使用壽(shou)命縮短，嚴重時(shi)還會造成(cheng)火災。電(dian)(dian)(dian)動機過(guo)熱(re)往往是電(dian)(dian)(dian)動機故障的綜合表(biao)現，也是造成(cheng)電(dian)(dian)(dian)動機損壞的主(zhu)要原因。電(dian)(dian)(dian)動機過(guo)熱(re)，首先要尋找熱(re)源，即(ji)是由哪一(yi)部(bu)件的發熱(re)造成(cheng)的，進而(er)找出引起這些部(bu)件過(guo)熱(re)的原因。
若拖動(dong)機械傳動(dong)帶(dai)太緊和(he)轉(zhuan)軸運(yun)轉(zhuan)不(bu)靈活，可造成電動(dong)機長期過載(zai)(zai)運(yun)行。這時應會問(wen)機械維修人員適當放松傳動(dong)帶(dai)，拆開檢查(cha)機械設備位轉(zhuan)軸靈活，并設法調(diao)整負載(zai)(zai)，使(shi)電動(dong)機保持在額定(ding)負載(zai)(zai)狀態下運(yun)行。
如電動機在陽光下曝曬，環境溫(wen)(wen)度超過(guo)40℃，或在通風(feng)不暢的(de)環境條件(jian)下運行，會引起電動機溫(wen)(wen)升(sheng)道高。可搭簡(jian)易涼(liang)棚遮蔭或用鼓風(feng)機、風(feng)扇吹風(feng)，更應(ying)注意(yi)清除電動機本(ben)身通風(feng)道的(de)油(you)污及灰(hui)塵，以改(gai)善(shan)冷卻條件(jian)。
電(dian)(dian)(dian)(dian)動機(ji)在電(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)壓(ya)(ya)變(bian)動-5％—+10％范(fan)圍內運行時(shi)，可保持(chi)額定(ding)功率(lv)不(bu)變(bian)。若(ruo)電(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)壓(ya)(ya)超(chao)過額定(ding)電(dian)(dian)(dian)(dian)壓(ya)(ya)的10％，會引(yin)起(qi)鐵心磁通(tong)密度(du)急劇增加，使鐵損增大(da)而導(dao)致電(dian)(dian)(dian)(dian)動機(ji)過熱(re)。具體檢(jian)查(cha)方法是(shi)，用(yong)交流電(dian)(dian)(dian)(dian)壓(ya)(ya)表測量(liang)母線電(dian)(dian)(dian)(dian)壓(ya)(ya)或電(dian)(dian)(dian)(dian)動機(ji)的端電(dian)(dian)(dian)(dian)壓(ya)(ya)，若(ruo)是(shi)電(dian)(dian)(dian)(dian)網電(dian)(dian)(dian)(dian)壓(ya)(ya)原因，應向供電(dian)(dian)(dian)(dian)部門反(fan)映解決；若(ruo)是(shi)電(dian)(dian)(dian)(dian)路壓(ya)(ya)降過大(da)，應更換較(jiao)大(da)截面積的導(dao)線和縮短電(dian)(dian)(dian)(dian)動機(ji)與電(dian)(dian)(dian)(dian)源的距離。
若電源(yuan)斷相(xiang)，使電動機單相(xiang)運行，短(duan)時間就會(hui)造(zao)成電動機的繞組急劇發熱而導致燒(shao)毀。因此，應先檢查電動機的熔(rong)斷器和開(kai)關狀況，然后用萬用表測量前部(bu)線路(lu)。
使損耗增加而發熱，可在停(ting)機后測試(shi)轉子溫(wen)度，查找故(gu)障原因并予以排除。
電(dian)動(dong)機起動(dong)頻繁或正反轉次數過多(duo)，應限制起動(dong)次數，正確選(xuan)用過熱保護(hu)或更換(huan)適(shi)合生產要求(qiu)的電(dian)動(dong)機。
應檢查定子繞(rao)組相(xiang)間或匝間短路(lu)及定子繞(rao)組接地情況。
應檢(jian)查軸承(cheng)室的溫(wen)度是否高于其他(ta)部位；檢(jian)查潤(run)滑脂是否太少或干枯。
是(shi)因風(feng)路堵塞或散熱片積灰太多(duo)、油垢太厚而影(ying)響(xiang)散熱。
會引起局部溫(wen)升過高，應抽(chou)心檢查(cha)，找出故(gu)障(zhang)原因進行(xing)排(pai)除(chu)。
采用軸流式風扇的電動機(ji)，若風扇旋轉方向反了，也(ye)會造成電動機(ji)過熱。
引起電(dian)動(dong)機(ji)(ji)(ji)過電(dian)流發熱，甚(shen)至使電(dian)動(dong)機(ji)(ji)(ji)卡住不造成(cheng)電(dian)動(dong)機(ji)(ji)(ji)溫(wen)度急劇(ju)上升(sheng)，繞組很快(kuai)被燒壞(huai)。
將會造成電(dian)動機(ji)在試運行時(shi)發熱，可測(ce)量電(dian)動機(ji)的三(san)相空載(zai)電(dian)流，若三(san)相空載(zai)電(dian)流大于額定值(zhi)，說明(ming)匝(za)數(shu)不足，應增加匝(za)數(shu)。
雖然可以起(qi)動并帶負載(zai)運行，但負載(zai)稍大電流就會超過(guo)額(e)定(ding)電流引起(qi)發熱(re)；薦丫聯結(jie)電動機誤接成(cheng)△聯結(jie)，空載(zai)時即可超過(guo)額(e)定(ding)電流而(er)無法運行。
