防爆型三相變頻調速電動機

輸入電(dian)(dian)壓(ya)變化。與電(dian)(dian)機的額定電(dian)(dian)壓(ya)相(xiang)(xiang)比，實際(ji)運(yun)行(xing)時輸入的電(dian)(dian)壓(ya)都會有不(bu)同程度的偏差，運(yun)行(xing)電(dian)(dian)壓(ya)略低(di)于額定電(dian)(dian)壓(ya)（但(dan)不(bu)能低(di)于10%，在2-3%之間(jian)）時，保證電(dian)(dian)機正常(chang)運(yun)行(xing)的同時，電(dian)(dian)機損耗要小；相(xiang)(xiang)反，當電(dian)(dian)機運(yun)行(xing)電(dian)(dian)壓(ya)高于額定電(dian)(dian)壓(ya)時，電(dian)(dian)機損耗會增(zeng)加，若超出過(guo)多(duo)，電(dian)(dian)機電(dian)(dian)流(liu)增(zeng)加過(guo)大甚至(zhi)導致燒毀故障。

電壓(ya)不(bu)平(ping)損耗。若(ruo)輸入電壓(ya)不(bu)平(ping)衡，將(jiang)導致異步(bu)電機電流(liu)不(bu)平(ping)。因負序電流(liu)的存在導致電機的轉(zhuan)矩減(jian)小。

電源頻率變化。對于風機泵類負載，軸轉矩與轉速的平方成正比變化，頻率降低后，轉速下降，轉矩也下降，定子、、轉子電流下降，因而電機效率有所提高，再加上軸功率有大幅度下降，電機輸入功率同樣大幅度下降，所以風機泵類負載采用變頻調速，在低速時可獲得好的節能效果。
非正弦波形電源供電。大多數變頻器輸出電壓波形是非正弦波，在異步電機中產生諧波電流及諧波磁動勢，這勢必會造成電機雜散損耗的增加。

電(dian)(dian)機起(qi)動(dong)(dong)和停機損耗。有(you)些負載要求斷續(xu)運行，甚至頻(pin)繁起(qi)動(dong)(dong)，這(zhe)樣將會(hui)使(shi)定(ding)子(zi)繞組頻(pin)繁受到沖擊力(li)，鼠籠轉子(zi)也(ye)會(hui)因發熱(re)不均勻，產生熱(re)應力(li)，反復起(qi)動(dong)(dong)會(hui)使(shi)轉子(zi)導條斷裂。起(qi)動(dong)(dong)時電(dian)(dian)機發熱(re)增多(duo)而散熱(re)條件較穩態運行差，多(duo)次起(qi)動(dong)(dong)也(ye)會(hui)使(shi)電(dian)(dian)機過熱(re)。因此在(zai)規定(ding)時間內對起(qi)動(dong)(dong)次數及時間間隔(ge)都有(you)規定(ding)。采用高(gao)轉子(zi)電(dian)(dian)阻電(dian)(dian)機，可(ke)以(yi)減(jian)少(shao)定(ding)轉子(zi)起(qi)動(dong)(dong)電(dian)(dian)流(liu)，所以(yi)可(ke)減(jian)少(shao)能耗及電(dian)(dian)流(liu)沖擊影響。

防爆型三相變頻調速電動機

電動機的(de)工(gong)作是電動機在(zai)額定條件下的(de)連續運行時(shi)間。電動機必(bi)須適應這(zhe)種(zhong)情況，以(yi)確(que)保在(zai)運行過(guo)程中(zhong)電動機的(de)溫(wen)度不會(hui)超過(guo)極(ji)限。電機的(de)工(gong)作原理是對電機空載、故障、停機時(shi)間、持續時(shi)間和順序的(de)具體描述。

定期檢修：

為了避免和減少三(san)相異(yi)(yi)步(bu)電(dian)(dian)動機突然損壞事故，三(san)相異(yi)(yi)步(bu)電(dian)(dian)動機需(xu)要定期保養和檢修(xiu)。如遇有(you)電(dian)(dian)動機過熱和定子繞組(zu)絕緣太(tai)低(di)時，須立(li)即進(jin)行檢修(xiu)。三(san)相異(yi)(yi)步(bu)電(dian)(dian)動機的檢修(xiu)方(fang)法是：將(jiang)電(dian)(dian)動機進(jin)行解體，對各零件先進(jin)行清理，再對它們作表觀檢查(cha)，是否有(you)異(yi)(yi)常(chang)。對電(dian)(dian)機繞組(zu)作電(dian)(dian)氣(qi)檢查(cha)。

1、機(ji)械檢(jian)(jian)(jian)查 檢(jian)(jian)(jian)查電機(ji)的外(wai)殼(ke)和(he)(he)端蓋是(shi)(shi)否(fou)(fou)(fou)(fou)(fou)有裂縫(feng)現象(xiang)，如有裂縫(feng)應(ying)進行焊接和(he)(he)更換。應(ying)檢(jian)(jian)(jian)查轉(zhuan)(zhuan)妯(zhou)(zhou)(zhou)是(shi)(shi)否(fou)(fou)(fou)(fou)(fou)彎曲(qu)，裝配工(gong)藝(yi)是(shi)(shi)否(fou)(fou)(fou)(fou)(fou)妥當。另外(wai)用手撥動轉(zhuan)(zhuan)子(zi)，看是(shi)(shi)否(fou)(fou)(fou)(fou)(fou)能(neng)轉(zhuan)(zhuan)動，如轉(zhuan)(zhuan)不動看是(shi)(shi)否(fou)(fou)(fou)(fou)(fou)有異(yi)物(wu)卡(ka)住，妯(zhou)(zhou)(zhou)承(cheng)是(shi)(shi)否(fou)(fou)(fou)(fou)(fou)良好。然后根據情(qing)況更換妯(zhou)(zhou)(zhou)承(cheng)、妯(zhou)(zhou)(zhou)套。測量檢(jian)(jian)(jian)查葉輪的上、下外(wai)止口和(he)(he)與它們相配合的扣環及電機(ji)內徑(jing)的尺(chi)寸，這(zhe)兩(liang)個配合間隙是(shi)(shi)否(fou)(fou)(fou)(fou)(fou)在檢(jian)(jian)(jian)修(xiu)標準(zhun)規定(ding)的范圍內，超(chao)差時需更換零件或采取其它措(cuo)施（如：堆(dui)焊、鑲套）使配合間隙達到規定(ding)要(yao)求。否(fou)(fou)(fou)(fou)(fou)則將影響電機(ji)的性能(neng)、妯(zhou)(zhou)(zhou)向(xiang)均衡力等。觀(guan)察檢(jian)(jian)(jian)查定(ding)、轉(zhuan)(zhuan)子(zi)的表觀(guan)情(qing)況，尤其要(yao)注意焊縫(feng)處有無異(yi)常(chang)情(qing)況。 

2、電(dian)(dian)(dian)(dian)(dian)氣檢查(cha) 直流電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)檢查(cha)：三相電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)的(de)不均衡度不得超過2%。絕(jue)緣電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)檢查(cha)：三相異步電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)繞(rao)組(zu)的(de)絕(jue)緣電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)一般能達(da)到100MΩ以上。如低于5MΩ時需(xu)分析(xi)原因(yin)，絕(jue)緣是(shi)否受(shou)潮(chao)，或繞(rao)組(zu)因(yin)絕(jue)緣不好而接地等，如經(jing)電(dian)(dian)(dian)(dian)(dian)橋實(shi)(shi)驗(yan)檢測三相電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)均衡無問題，則純(chun)屬絕(jue)緣受(shou)潮(chao)，需(xu)進行干燥處理(li)，如定子(zi)三相電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)不均衡，則需(xu)對電(dian)(dian)(dian)(dian)(dian)機(ji)線圈(quan)三相分別做對地耐壓(ya)實(shi)(shi)驗(yan)及匝間(jian)實(shi)(shi)驗(yan)，查(cha)出接地點。