大型三相異步電機

異步電動機按照轉子結構分為兩種形式:有鼠籠式(鼠籠式異步電機)、繞線式異步電動機。

作電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)(ji)運行的(de)(de)(de)(de)異步(bu)(bu)(bu)電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)(ji)(ji)。因其(qi)轉子繞組電(dian)(dian)(dian)(dian)(dian)流是感應產生的(de)(de)(de)(de)，又稱感應電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)(ji)。異步(bu)(bu)(bu)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)(ji)是各類電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)(ji)中(zhong)(zhong)應用(yong)*、需(xu)要量(liang)最大的(de)(de)(de)(de)一種。各國的(de)(de)(de)(de)以電(dian)(dian)(dian)(dian)(dian)為動(dong)(dong)(dong)力(li)的(de)(de)(de)(de)機(ji)(ji)(ji)(ji)(ji)械中(zhong)(zhong)，約有90%左右(you)為異步(bu)(bu)(bu)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)(ji)，其(qi)中(zhong)(zhong)小型異步(bu)(bu)(bu)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)(ji)約占(zhan)70%以上。在電(dian)(dian)(dian)(dian)(dian)力(li)系統的(de)(de)(de)(de)總負荷(he)中(zhong)(zhong)，異步(bu)(bu)(bu)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)(ji)的(de)(de)(de)(de)用(yong)電(dian)(dian)(dian)(dian)(dian)量(liang)占(zhan)相當大的(de)(de)(de)(de)比重。在中(zhong)(zhong)國，異步(bu)(bu)(bu)電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)(ji)(ji)(ji)的(de)(de)(de)(de)用(yong)電(dian)(dian)(dian)(dian)(dian)量(liang)約占(zhan)總負荷(he)的(de)(de)(de)(de)60%多。

大型三相異步電機原理

特點

1.小型輕量化。
2.易實現轉速超過10 000r/min 的高速旋轉。
3.高速低轉矩時運轉效率高。
4.低速時有高轉矩，以及有寬泛的速度控制范圍。
5.高可靠性(堅固)。
6.制造成本低。
7.控(kong)制裝置的簡單化。

異步(bu)電(dian)動機(ji)(ji)的(de)基本(ben)特點是(shi)，轉子繞組不需與(yu)其(qi)他(ta)電(dian)源相(xiang)連(lian)，其(qi)定子電(dian)流(liu)直接取自交流(liu)電(dian)力系統;與(yu)其(qi)他(ta)電(dian)機(ji)(ji)相(xiang)比(bi)，異步(bu)電(dian)動機(ji)(ji)的(de)結構簡單，制造、使用、維(wei)護(hu)方便，運行可(ke)靠性高，重(zhong)量輕(qing)，成本(ben)低(di)。以三相(xiang)異步(bu)電(dian)動機(ji)(ji)為(wei)例，與(yu)同(tong)功率、同(tong)轉速的(de)直流(liu)電(dian)動機(ji)(ji)相(xiang)比(bi)，前者重(zhong)量只及后(hou)者的(de)二分之一，成本(ben)僅(jin)為(wei)三分之一。

工作原理

當向三相定(ding)(ding)子(zi)繞(rao)組(zu)中通入對(dui)稱(cheng)的(de)(de)三相交流電(dian)(dian)時(shi)，就產生了一個以同(tong)步轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)速(su)n1沿定(ding)(ding)子(zi)和轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)子(zi)內(nei)圓(yuan)空間(jian)作順時(shi)針方向旋(xuan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)的(de)(de)旋(xuan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)磁(ci)(ci)(ci)(ci)(ci)場(chang)(chang)。由于旋(xuan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)磁(ci)(ci)(ci)(ci)(ci)場(chang)(chang)以n1轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)速(su)旋(xuan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)，轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)子(zi)導體(ti)開始時(shi)是靜止的(de)(de)，故轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)子(zi)導體(ti)將切(qie)割(ge)定(ding)(ding)子(zi)旋(xuan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)磁(ci)(ci)(ci)(ci)(ci)場(chang)(chang)而產生感(gan)應(ying)(ying)電(dian)(dian)動(dong)(dong)勢(shi)（感(gan)應(ying)(ying)電(dian)(dian)動(dong)(dong)勢(shi)的(de)(de)方向用右手定(ding)(ding)則判定(ding)(ding)）。由于轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)子(zi)導體(ti)兩端被(bei)短(duan)路環短(duan)接，在(zai)感(gan)應(ying)(ying)電(dian)(dian)動(dong)(dong)勢(shi)的(de)(de)作用下(xia)，轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)子(zi)導體(ti)中將產生與感(gan)應(ying)(ying)電(dian)(dian)動(dong)(dong)勢(shi)方向基本一致的(de)(de)感(gan)生電(dian)(dian)流。轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)子(zi)的(de)(de)載流導體(ti)在(zai)定(ding)(ding)子(zi)磁(ci)(ci)(ci)(ci)(ci)場(chang)(chang)中受到電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)力的(de)(de)作用（力的(de)(de)方向用左(zuo)手定(ding)(ding)則判定(ding)(ding)）。電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)力對(dui)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)子(zi)軸產生電(dian)(dian)磁(ci)(ci)(ci)(ci)(ci)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)矩(ju)，驅動(dong)(dong)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)子(zi)沿著旋(xuan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)磁(ci)(ci)(ci)(ci)(ci)場(chang)(chang)方向旋(xuan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)。

通(tong)過上述分析可(ke)以總結(jie)出(chu)電(dian)(dian)(dian)動(dong)機工作原理(li)為：當電(dian)(dian)(dian)動(dong)機的三(san)相(xiang)定(ding)子(zi)繞組(zu)(zu)（各相(xiang)差120度(du)電(dian)(dian)(dian)角(jiao)度(du)），通(tong)入三(san)相(xiang)對稱(cheng)交流(liu)電(dian)(dian)(dian)后，將產(chan)生一個旋(xuan)轉(zhuan)(zhuan)磁(ci)(ci)(ci)場(chang)，該旋(xuan)轉(zhuan)(zhuan)磁(ci)(ci)(ci)場(chang)切割(ge)轉(zhuan)(zhuan)子(zi)繞組(zu)(zu)，從而(er)在(zai)轉(zhuan)(zhuan)子(zi)繞組(zu)(zu)中產(chan)生感應(ying)電(dian)(dian)(dian)流(liu)（轉(zhuan)(zhuan)子(zi)繞組(zu)(zu)是(shi)閉(bi)合通(tong)路），載流(liu)的轉(zhuan)(zhuan)子(zi)導體在(zai)定(ding)子(zi)旋(xuan)轉(zhuan)(zhuan)磁(ci)(ci)(ci)場(chang)作用下將產(chan)生電(dian)(dian)(dian)磁(ci)(ci)(ci)力，從而(er)在(zai)電(dian)(dian)(dian)機轉(zhuan)(zhuan)軸上形(xing)成電(dian)(dian)(dian)磁(ci)(ci)(ci)轉(zhuan)(zhuan)矩，驅動(dong)電(dian)(dian)(dian)動(dong)機旋(xuan)轉(zhuan)(zhuan)，并且電(dian)(dian)(dian)機旋(xuan)轉(zhuan)(zhuan)方向(xiang)與(yu)旋(xuan)轉(zhuan)(zhuan)磁(ci)(ci)(ci)場(chang)方向(xiang)相(xiang)同。

基本結構

三(san)(san)相異(yi)步電動機(ji)由固定(ding)的(de)定(ding)子(zi)(zi)和(he)旋轉(zhuan)的(de)轉(zhuan)子(zi)(zi)兩(liang)個(ge)基本部分組(zu)成，轉(zhuan)子(zi)(zi)裝在定(ding)子(zi)(zi)內腔里，借助軸承被支撐在兩(liang)個(ge)端蓋上。為了保證轉(zhuan)子(zi)(zi)能(neng)在定(ding)子(zi)(zi)內自(zi)由轉(zhuan)動，定(ding)子(zi)(zi)和(he)轉(zhuan)子(zi)(zi)之間必須有一間隙(xi)(xi)，稱(cheng)為氣隙(xi)(xi)。電動機(ji)的(de)氣隙(xi)(xi)是(shi)一個(ge)非(fei)常重要的(de)參數(shu)，其大(da)小(xiao)及對稱(cheng)性(xing)等(deng)對電動機(ji)的(de)性(xing)能(neng)有很大(da)影響。圖2所示為三(san)(san)相籠(long)型(xing)異(yi)步電動機(ji)的(de)組(zu)成部件。