第5章異步電機(jī)(2)

1、電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT第五章第五章 異步電機(jī)（二）異步電機(jī)（二）Chapter 5 Chapter 5 Induction Machine(2Induction Machine(2) )電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepart

2、ment of Electrical Engineering, HFUT第一節(jié)第一節(jié) 三相異步電動(dòng)機(jī)運(yùn)行時(shí)的電磁過程三相異步電動(dòng)機(jī)運(yùn)行時(shí)的電磁過程一、一、異步電動(dòng)機(jī)負(fù)載時(shí)的物理情況異步電動(dòng)機(jī)負(fù)載時(shí)的物理情況（1）三相異步電動(dòng)機(jī)的定子繞組接到對(duì)稱三相電源時(shí)，定子繞組）三相異步電動(dòng)機(jī)的定子繞組接到對(duì)稱三相電源時(shí)，定子繞組中就通過三相交流電流，這個(gè)對(duì)稱三相交流電流將在氣隙內(nèi)形成按中就通過三相交流電流，這個(gè)對(duì)稱三相交流電流將在氣隙內(nèi)形成按正弦規(guī)律分布、并且以同步轉(zhuǎn)速正弦規(guī)律分布、并且以同步轉(zhuǎn)速n0旋轉(zhuǎn)的旋轉(zhuǎn)磁動(dòng)勢(shì)旋轉(zhuǎn)的旋轉(zhuǎn)磁動(dòng)勢(shì)F1，由旋轉(zhuǎn)磁，由旋轉(zhuǎn)磁動(dòng)勢(shì)動(dòng)勢(shì)F1建立旋轉(zhuǎn)的氣隙主磁場(chǎng)建立旋轉(zhuǎn)的氣隙主磁

3、場(chǎng)Bm。 （2）這個(gè)旋轉(zhuǎn)磁場(chǎng)切割定子、轉(zhuǎn)子繞組，分別在定子、轉(zhuǎn)子繞組）這個(gè)旋轉(zhuǎn)磁場(chǎng)切割定子、轉(zhuǎn)子繞組，分別在定子、轉(zhuǎn)子繞組內(nèi)感應(yīng)出定子電動(dòng)勢(shì)和轉(zhuǎn)子電動(dòng)勢(shì)。在轉(zhuǎn)子電動(dòng)勢(shì)作用下轉(zhuǎn)子回路內(nèi)感應(yīng)出定子電動(dòng)勢(shì)和轉(zhuǎn)子電動(dòng)勢(shì)。在轉(zhuǎn)子電動(dòng)勢(shì)作用下轉(zhuǎn)子回路中有對(duì)稱三相電流流過。于是，在氣隙磁場(chǎng)和轉(zhuǎn)子電流的相互作用中有對(duì)稱三相電流流過。于是，在氣隙磁場(chǎng)和轉(zhuǎn)子電流的相互作用下，產(chǎn)生了電磁轉(zhuǎn)矩，轉(zhuǎn)子就順著旋轉(zhuǎn)磁場(chǎng)的方向轉(zhuǎn)動(dòng)。下，產(chǎn)生了電磁轉(zhuǎn)矩，轉(zhuǎn)子就順著旋轉(zhuǎn)磁場(chǎng)的方向轉(zhuǎn)動(dòng)。電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engin

4、eering, HFUTDepartment of Electrical Engineering, HFUT空載的情況下：空載的情況下：nn0, I20 當(dāng)電機(jī)帶有機(jī)械負(fù)載后：當(dāng)電機(jī)帶有機(jī)械負(fù)載后：nn0, I2增大。增大。AUAIBUBICUCIAFBFCF1FmBABCAEBECEabcaEbEbEaIbIcIaFbFcF2F電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT)240sin

5、(2)120sin(2sin2111111tNfetNfetNfeyCyByA根據(jù)前一章的知識(shí)可知，定子三相的感應(yīng)電根據(jù)前一章的知識(shí)可知，定子三相的感應(yīng)電動(dòng)勢(shì)表達(dá)式為：動(dòng)勢(shì)表達(dá)式為：若轉(zhuǎn)子靜止，轉(zhuǎn)子三相的感應(yīng)電動(dòng)勢(shì)表若轉(zhuǎn)子靜止，轉(zhuǎn)子三相的感應(yīng)電動(dòng)勢(shì)表達(dá)式為：達(dá)式為：)240sin(2)120sin(2)sin(2121012101210tNfetNfetNfeycybya電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Eng

6、ineering, HFUT下面分析轉(zhuǎn)子運(yùn)動(dòng)時(shí)的轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)。下面分析轉(zhuǎn)子運(yùn)動(dòng)時(shí)的轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)。當(dāng)轉(zhuǎn)子運(yùn)動(dòng)時(shí)，當(dāng)轉(zhuǎn)子運(yùn)動(dòng)時(shí)，-t是隨著時(shí)間變化的（是隨著時(shí)間變化的（ 為轉(zhuǎn)子機(jī)械角速為轉(zhuǎn)子機(jī)械角速度，度，rad/srad/s），根據(jù)前一章的推導(dǎo)，），根據(jù)前一章的推導(dǎo)，axax、byby、czcz繞組所交鏈的磁通表達(dá)式為繞組所交鏈的磁通表達(dá)式為)240cos()120cos()cos(111ttttttcba根據(jù)電磁感應(yīng)公式根據(jù)電磁感應(yīng)公式dtdNecbaycba,2,電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electr

7、ical Engineering, HFUTDepartment of Electrical Engineering, HFUT240)sin()(120)sin()()sin()(121212tNetNetNeycybya可以求出轉(zhuǎn)子運(yùn)動(dòng)時(shí)的感應(yīng)電動(dòng)勢(shì)為可以求出轉(zhuǎn)子運(yùn)動(dòng)時(shí)的感應(yīng)電動(dòng)勢(shì)為fssnnnpfnpfffss26060221111推導(dǎo)幾個(gè)關(guān)系推導(dǎo)幾個(gè)關(guān)系電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineer

8、ing, HFUT240)sin()(120)sin()()sin()(121212tNetNetNeycybya可以求出轉(zhuǎn)子運(yùn)動(dòng)時(shí)的感應(yīng)電動(dòng)勢(shì)為可以求出轉(zhuǎn)子運(yùn)動(dòng)時(shí)的感應(yīng)電動(dòng)勢(shì)為240sin2120sin2sin2121121121tsNfsetsNfsetsNfseycybya上式可以寫為上式可以寫為可以看出，不管轉(zhuǎn)速為多少，感應(yīng)電動(dòng)勢(shì)總是三相對(duì)稱的?？梢钥闯觯还苻D(zhuǎn)速為多少，感應(yīng)電動(dòng)勢(shì)總是三相對(duì)稱的。電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment

9、of Electrical Engineering, HFUT240sin2120sin2sin2121121121tsNfsetsNfsetsNfseycybya轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)的瞬時(shí)值為轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)的瞬時(shí)值為注意：定子和轉(zhuǎn)子中的電動(dòng)勢(shì)是不同頻率的，定子電動(dòng)勢(shì)頻率為注意：定子和轉(zhuǎn)子中的電動(dòng)勢(shì)是不同頻率的，定子電動(dòng)勢(shì)頻率為f，轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)為轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)為sf考慮轉(zhuǎn)子也采用了短距和分布線圈形式，轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)的有效值考慮轉(zhuǎn)子也采用了短距和分布線圈形式，轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)的有效值為為12211221244. 422wwskNsfkNfsE電機(jī)學(xué)電機(jī)學(xué) Electric machineryElect

10、ric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT若轉(zhuǎn)子回路閉合，則轉(zhuǎn)子內(nèi)將有電流流通，轉(zhuǎn)子電流的頻若轉(zhuǎn)子回路閉合，則轉(zhuǎn)子內(nèi)將有電流流通，轉(zhuǎn)子電流的頻率與轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)頻率一致，并且也互差率與轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)頻率一致，并且也互差120120o o；因此因此轉(zhuǎn)子也是對(duì)稱三相對(duì)稱電流流過對(duì)稱三相繞組轉(zhuǎn)子也是對(duì)稱三相對(duì)稱電流流過對(duì)稱三相繞組，所產(chǎn)，所產(chǎn)生的磁動(dòng)勢(shì)也為旋轉(zhuǎn)磁動(dòng)勢(shì)。生的磁動(dòng)勢(shì)也為旋轉(zhuǎn)磁動(dòng)勢(shì)。2、F2轉(zhuǎn)速的大小轉(zhuǎn)速的大小 如果相序?yàn)槿绻嘈驗(yàn)锳-B-

11、C的異步電動(dòng)機(jī)定子電流所產(chǎn)生的旋轉(zhuǎn)磁場(chǎng)按的異步電動(dòng)機(jī)定子電流所產(chǎn)生的旋轉(zhuǎn)磁場(chǎng)按逆時(shí)針方向旋轉(zhuǎn)，因?yàn)槟鏁r(shí)針方向旋轉(zhuǎn)，因?yàn)閚n0，則轉(zhuǎn)子電流相序?yàn)?，則轉(zhuǎn)子電流相序?yàn)閍-b-c 。則轉(zhuǎn)子磁。則轉(zhuǎn)子磁動(dòng)勢(shì)動(dòng)勢(shì)F2的旋轉(zhuǎn)方向也按照相序的旋轉(zhuǎn)方向也按照相序a-b-c，即：按逆時(shí)針方向。，即：按逆時(shí)針方向。1、轉(zhuǎn)子磁動(dòng)勢(shì)、轉(zhuǎn)子磁動(dòng)勢(shì)F2的旋轉(zhuǎn)方向的旋轉(zhuǎn)方向 轉(zhuǎn)子繞組內(nèi)感應(yīng)電動(dòng)勢(shì)和電流的頻率為轉(zhuǎn)子繞組內(nèi)感應(yīng)電動(dòng)勢(shì)和電流的頻率為1000026060)(sfnnnpnnnpff2為轉(zhuǎn)差頻率，轉(zhuǎn)子電流形成的為轉(zhuǎn)差頻率，轉(zhuǎn)子電流形成的轉(zhuǎn)子磁動(dòng)勢(shì)轉(zhuǎn)子磁動(dòng)勢(shì)F2的旋轉(zhuǎn)方向與的旋轉(zhuǎn)方向與F1的旋的旋轉(zhuǎn)方向相同，它相對(duì)于轉(zhuǎn)子

12、的轉(zhuǎn)速為轉(zhuǎn)方向相同，它相對(duì)于轉(zhuǎn)子的轉(zhuǎn)速為n，而相對(duì)于定子的轉(zhuǎn)速為，而相對(duì)于定子的轉(zhuǎn)速為n+n=n0電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT磁動(dòng)勢(shì)平衡關(guān)系磁動(dòng)勢(shì)平衡關(guān)系轉(zhuǎn)子磁動(dòng)勢(shì)轉(zhuǎn)子磁動(dòng)勢(shì)F2與定子磁動(dòng)勢(shì)與定子磁動(dòng)勢(shì)F1相對(duì)靜止，得到合成磁動(dòng)勢(shì)相對(duì)靜止，得到合成磁動(dòng)勢(shì)F1+F2負(fù)載時(shí)負(fù)載時(shí))(21mmmBFFF空載時(shí)空載時(shí))(00010mmmBFF電動(dòng)機(jī)從空載到負(fù)載，電動(dòng)機(jī)從空載到負(fù)載

13、，定子繞組的感應(yīng)電動(dòng)勢(shì)的變化很小定子繞組的感應(yīng)電動(dòng)勢(shì)的變化很小，差不，差不多和電源電壓相平衡。所以，可以近似認(rèn)為多和電源電壓相平衡。所以，可以近似認(rèn)為0mm于是于是mmmFFFF021)(21FFFm電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT異步電機(jī)中時(shí)間相量和空間矢量的關(guān)系異步電機(jī)中時(shí)間相量和空間矢量的關(guān)系時(shí)間參考軸也取時(shí)間參考軸也取A相軸線。即相軸線。即A相電流相相電流相量在起始時(shí)

14、刻位于量在起始時(shí)刻位于A相軸線上，此時(shí)相軸線上，此時(shí)A相相電流達(dá)到最大。電流達(dá)到最大。任何時(shí)刻某一相的電流瞬時(shí)值為該相量任何時(shí)刻某一相的電流瞬時(shí)值為該相量在該相軸線上的投影。在該相軸線上的投影。時(shí)間相量與空間矢量的耦合在某一個(gè)線時(shí)間相量與空間矢量的耦合在某一個(gè)線圈所交鏈的磁通是正弦變化的這一概念圈所交鏈的磁通是正弦變化的這一概念中得到了體現(xiàn)。中得到了體現(xiàn)。在上一章的分析中，得出如下結(jié)論：在上一章的分析中，得出如下結(jié)論：當(dāng)某一相電流達(dá)到最大值時(shí)，勵(lì)磁磁動(dòng)勢(shì)的幅值與該相軸線相重合。當(dāng)某一相電流達(dá)到最大值時(shí)，勵(lì)磁磁動(dòng)勢(shì)的幅值與該相軸線相重合。因此選擇因此選擇A相軸線作為空間參考軸，表示空間位置的起點(diǎn)

15、。相軸線作為空間參考軸，表示空間位置的起點(diǎn)。)cos(1t電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT兩極異步電動(dòng)機(jī)的定子、轉(zhuǎn)子繞組示意圖負(fù)載時(shí)定子、轉(zhuǎn)子磁動(dòng)勢(shì)和電流的相矢圖電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrica

16、l Engineering, HFUTmB)(mMFIsE2)(11FI)(22FI電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT電磁關(guān)系電磁關(guān)系定子、轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)有效值定子、轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)有效值mWkNfE111144. 4mWskNfE222244. 4相量表達(dá)式相量表達(dá)式mWkNfjE111144. 4mWmWskNsfjkNfjE221222244. 444. 4定、轉(zhuǎn)子的漏磁通

17、在各自繞組中感應(yīng)產(chǎn)生漏電動(dòng)勢(shì)定、轉(zhuǎn)子的漏磁通在各自繞組中感應(yīng)產(chǎn)生漏電動(dòng)勢(shì)1111144. 4WkNfjEskNfjkNfjEsWsWs22212222244. 444. 4電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT異步電動(dòng)機(jī)的負(fù)載異步電動(dòng)機(jī)的負(fù)載運(yùn)行時(shí)的電磁關(guān)系運(yùn)行時(shí)的電磁關(guān)系電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment o

18、f Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT二、基本方程式二、基本方程式（一）（一）磁動(dòng)勢(shì)平衡方程式磁動(dòng)勢(shì)平衡方程式mFFF21222221111111129 . 029 . 029 . 0IpkNmFIpkNmFIpkNmFWmWmW式中式中m1、m2為定子、轉(zhuǎn)子的相數(shù)；為定子、轉(zhuǎn)子的相數(shù)；Im為對(duì)應(yīng)于勵(lì)磁磁動(dòng)勢(shì)的勵(lì)磁電為對(duì)應(yīng)于勵(lì)磁磁動(dòng)勢(shì)的勵(lì)磁電流。流。mWWWIpkNmIpkNmIpkNm1112222111129 . 029 . 029 . 022222111229 . 029 . 0Ip

19、kNmIpkNmFWW)(21IIIm勵(lì)磁電流負(fù)載電流令令221IkIi則則mIII21222111WWikNmkNmk 異步電動(dòng)機(jī)的電流比電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT（二）（二）電動(dòng)勢(shì)平衡方程式電動(dòng)勢(shì)平衡方程式1111 12222()()()()ssUEEI rEEIrR R為轉(zhuǎn)子電阻的外加電阻為轉(zhuǎn)子電阻的外加電阻)(1mmmmmjxrIZIEZm為表征鐵心磁化特性和鐵

20、耗的一個(gè)綜合參數(shù)，稱為勵(lì)磁阻抗；為表征鐵心磁化特性和鐵耗的一個(gè)綜合參數(shù)，稱為勵(lì)磁阻抗；xm稱為勵(lì)磁電抗；稱為勵(lì)磁電抗；rm為反映鐵耗的勵(lì)磁電阻。為反映鐵耗的勵(lì)磁電阻。111xI jE定子漏電抗ssxI jE222轉(zhuǎn)子漏電抗skNfkNfEsWsWs22212222244. 444. 4因此因此sEEs22sxxs22sEEs22電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT旋轉(zhuǎn)時(shí)異步電動(dòng)機(jī)

21、的電路異步電動(dòng)機(jī)負(fù)載時(shí)的基本方程式列出如下異步電動(dòng)機(jī)負(fù)載時(shí)的基本方程式列出如下111111111ZIExI jrIEUsxI jRrIsEEs222222)(mmmmmZIjxrIE)(1miIIkI211定子電壓平衡方程：定子電壓平衡方程：轉(zhuǎn)子電壓平衡方程：轉(zhuǎn)子電壓平衡方程：電動(dòng)勢(shì)方程：電動(dòng)勢(shì)方程：磁動(dòng)勢(shì)平衡方程：磁動(dòng)勢(shì)平衡方程：電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT第二節(jié)第二節(jié)

22、 三相異步電動(dòng)機(jī)的等效電路及相量圖三相異步電動(dòng)機(jī)的等效電路及相量圖mWkNfjE221244. 4221121WWekNkNkEE為電動(dòng)勢(shì)比為電動(dòng)勢(shì)比轉(zhuǎn)子靜止時(shí)異步電動(dòng)機(jī)的定、轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)的關(guān)系轉(zhuǎn)子靜止時(shí)異步電動(dòng)機(jī)的定、轉(zhuǎn)子感應(yīng)電動(dòng)勢(shì)的關(guān)系mWkNfjE111144. 4電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT一、一、異步電動(dòng)機(jī)的等效電路異步電動(dòng)機(jī)的等效電路（一）（一）頻率歸算頻率

23、歸算異步電機(jī)中，由于轉(zhuǎn)子是旋轉(zhuǎn)的，隨著轉(zhuǎn)速不同，轉(zhuǎn)子電動(dòng)勢(shì)的頻異步電機(jī)中，由于轉(zhuǎn)子是旋轉(zhuǎn)的，隨著轉(zhuǎn)速不同，轉(zhuǎn)子電動(dòng)勢(shì)的頻率是不同的，這為問題的分析帶來了麻煩，因此需要將不同的轉(zhuǎn)速率是不同的，這為問題的分析帶來了麻煩，因此需要將不同的轉(zhuǎn)速變換到一個(gè)特定的轉(zhuǎn)速下研究問題。變換到一個(gè)特定的轉(zhuǎn)速下研究問題。頻率歸算頻率歸算 保持整個(gè)電磁系統(tǒng)的電磁性能不變，把一種頻率的參保持整個(gè)電磁系統(tǒng)的電磁性能不變，把一種頻率的參數(shù)和物理量換算成另一種頻率的參數(shù)和物理量。在這里，就是用一數(shù)和物理量換算成另一種頻率的參數(shù)和物理量。在這里，就是用一個(gè)具有定子頻率而等效于轉(zhuǎn)子的電路去代換實(shí)際轉(zhuǎn)子電路。個(gè)具有定子頻率而等效于

24、轉(zhuǎn)子的電路去代換實(shí)際轉(zhuǎn)子電路。所謂所謂“等效等效”是指：是指：1）進(jìn)行代換后，轉(zhuǎn)子電路對(duì)定子電路的電磁效應(yīng)不變。）進(jìn)行代換后，轉(zhuǎn)子電路對(duì)定子電路的電磁效應(yīng)不變。2）等效的轉(zhuǎn)子電路的電磁性能（有功功率、無功功率、銅耗等）等效的轉(zhuǎn)子電路的電磁性能（有功功率、無功功率、銅耗等）必須和實(shí)際轉(zhuǎn)子電路一樣。必須和實(shí)際轉(zhuǎn)子電路一樣。電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUTsjxrsEI222222

25、22/jxsrEI 靜止轉(zhuǎn)子電路中電流靜止轉(zhuǎn)子電路中電流222222222222)()/(IsxrsExsrEI 下面考慮兩種轉(zhuǎn)子電路下面考慮兩種轉(zhuǎn)子電路（1）靜止；（）靜止；（2）以轉(zhuǎn)差率）以轉(zhuǎn)差率s旋轉(zhuǎn)的轉(zhuǎn)子；旋轉(zhuǎn)的轉(zhuǎn)子；以轉(zhuǎn)差率以轉(zhuǎn)差率s旋轉(zhuǎn)的轉(zhuǎn)子旋轉(zhuǎn)的轉(zhuǎn)子222222229 . 02IpkNmFmFW從旋轉(zhuǎn)磁動(dòng)勢(shì)幅值的計(jì)算公式中可以看出，若保持兩者電流幅值相從旋轉(zhuǎn)磁動(dòng)勢(shì)幅值的計(jì)算公式中可以看出，若保持兩者電流幅值相等，則可以使兩者產(chǎn)生的旋轉(zhuǎn)磁動(dòng)勢(shì)幅值為相等。等，則可以使兩者產(chǎn)生的旋轉(zhuǎn)磁動(dòng)勢(shì)幅值為相等。x2指指50Hz下的電抗下的電抗值。值。若將轉(zhuǎn)子改為靜止以后，同時(shí)若將轉(zhuǎn)子改為靜止以后

26、，同時(shí)修改轉(zhuǎn)子電阻和電抗值，則可修改轉(zhuǎn)子電阻和電抗值，則可以保證轉(zhuǎn)子轉(zhuǎn)子電流幅值不變以保證轉(zhuǎn)子轉(zhuǎn)子電流幅值不變。電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT22222/rsxarctgsrxarctg 轉(zhuǎn)子真實(shí)電阻為轉(zhuǎn)子真實(shí)電阻為r2，但在等效靜止轉(zhuǎn)子中電阻為，但在等效靜止轉(zhuǎn)子中電阻為r2 /s，出現(xiàn)了一個(gè)附，出現(xiàn)了一個(gè)附加電阻。加電阻。21rss附加電阻上產(chǎn)生的功耗，實(shí)質(zhì)上表征了異步電

27、動(dòng)機(jī)的機(jī)械功率附加電阻上產(chǎn)生的功耗，實(shí)質(zhì)上表征了異步電動(dòng)機(jī)的機(jī)械功率變壓器模型變壓器模型電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT（二）（二）繞組歸算繞組歸算222111WWikNmkNmk 2222211129 . 029 . 0IpkNmIpkNmWW經(jīng)過頻率歸算以后，異步電機(jī)變成了變壓器模型。后面的處理過程經(jīng)過頻率歸算以后，異步電機(jī)變成了變壓器模型。后面的處理過程與變壓器的處理過

28、程完全一致，只是需要注意要在轉(zhuǎn)子產(chǎn)生的磁場(chǎng)與變壓器的處理過程完全一致，只是需要注意要在轉(zhuǎn)子產(chǎn)生的磁場(chǎng)中要考慮三相的合成磁場(chǎng)。中要考慮三相的合成磁場(chǎng)。用一個(gè)假想的轉(zhuǎn)子繞組替代真實(shí)的轉(zhuǎn)子繞組，它與定子繞組具有相用一個(gè)假想的轉(zhuǎn)子繞組替代真實(shí)的轉(zhuǎn)子繞組，它與定子繞組具有相同的參數(shù)。同的參數(shù)。假想轉(zhuǎn)子繞組和真實(shí)繞組需要產(chǎn)生同樣的旋轉(zhuǎn)磁動(dòng)勢(shì)。假想轉(zhuǎn)子繞組和真實(shí)繞組需要產(chǎn)生同樣的旋轉(zhuǎn)磁動(dòng)勢(shì)。221IkIi假想繞組流過假想電假想繞組流過假想電流所產(chǎn)生的磁動(dòng)勢(shì)。流所產(chǎn)生的磁動(dòng)勢(shì)。真實(shí)轉(zhuǎn)子繞組流過真實(shí)轉(zhuǎn)子真實(shí)轉(zhuǎn)子繞組流過真實(shí)轉(zhuǎn)子繞組所產(chǎn)生的磁動(dòng)勢(shì)。繞組所產(chǎn)生的磁動(dòng)勢(shì)。電機(jī)學(xué)電機(jī)學(xué) Electric machine

29、ryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT由轉(zhuǎn)子由轉(zhuǎn)子總的視在功率總的視在功率不變不變222221IEmIEm122EEkEe2211WWekNkNk 式中式中電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT由轉(zhuǎn)子銅耗和漏磁通儲(chǔ)

30、能不變由轉(zhuǎn)子銅耗和漏磁通儲(chǔ)能不變22222221rImrIm22rkkrie222222212121LImLIm22LkkLie22xkkxie轉(zhuǎn)子銅耗不變轉(zhuǎn)子銅耗不變由漏磁通儲(chǔ)能不變由漏磁通儲(chǔ)能不變計(jì)算出參數(shù)歸算關(guān)系為計(jì)算出參數(shù)歸算關(guān)系為異步電機(jī)歸算的總結(jié)異步電機(jī)歸算的總結(jié)電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT（三）（三）異步電動(dòng)機(jī)的等效電路異步電動(dòng)機(jī)的等效電路電機(jī)學(xué)電機(jī)學(xué) El

31、ectric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT經(jīng)過歸算后，定子、轉(zhuǎn)子的電動(dòng)勢(shì)方程式經(jīng)過歸算后，定子、轉(zhuǎn)子的電動(dòng)勢(shì)方程式11111111)(ZIEjxrIEU22222222221)(1ZIssrIx jrIssrIE 21EE磁動(dòng)勢(shì)方程式磁動(dòng)勢(shì)方程式mIII21勵(lì)磁支路的電動(dòng)勢(shì)方程式勵(lì)磁支路的電動(dòng)勢(shì)方程式mmZIE1電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDep

32、artment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT二、異步電動(dòng)機(jī)的相量圖二、異步電動(dòng)機(jī)的相量圖 根據(jù)根據(jù)T T形等效電路，可以畫出相應(yīng)的相量圖。形等效電路，可以畫出相應(yīng)的相量圖。m1EsRI22mI21EE22XI j2I1I1U11XI j11RI12mIII211111ZIEU22221ZIssRIEmmZIE1mwNfkjEE112144.4電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical E

33、ngineering, HFUTDepartment of Electrical Engineering, HFUT幾種異步電動(dòng)機(jī)的典型運(yùn)行情況幾種異步電動(dòng)機(jī)的典型運(yùn)行情況1、空載運(yùn)行、空載運(yùn)行0s21rss2、額度負(fù)載下運(yùn)行、額度負(fù)載下運(yùn)行05. 0Ns轉(zhuǎn)子電路基本上是電阻性的，功率因數(shù)較高。轉(zhuǎn)子電路基本上是電阻性的，功率因數(shù)較高。3、起動(dòng)時(shí)的情況、起動(dòng)時(shí)的情況0n1s012rss附加電阻為零，起動(dòng)電流很大，功率因數(shù)較低。附加電阻為零，起動(dòng)電流很大，功率因數(shù)較低。4、異步發(fā)電運(yùn)行、異步發(fā)電運(yùn)行 nn00s轉(zhuǎn)差率為負(fù)，附加電阻也為負(fù)值。表示從轉(zhuǎn)差率為負(fù)，附加電阻也為負(fù)值。表示從轉(zhuǎn)子軸上輸入轉(zhuǎn)子

34、軸上輸入（而不是輸（而不是輸出）機(jī)械功率。出）機(jī)械功率。5、電磁制動(dòng)狀態(tài)運(yùn)行、電磁制動(dòng)狀態(tài)運(yùn)行1s附加電阻為負(fù)值，表示從附加電阻為負(fù)值，表示從轉(zhuǎn)子軸上輸入轉(zhuǎn)子軸上輸入（而不是輸出）機(jī)械功率。（而不是輸出）機(jī)械功率。電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT（四）（四）等效電路的簡(jiǎn)化等效電路的簡(jiǎn)化異步電機(jī)近似等效電路電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric ma

35、chineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUTkWPN10VUN380min/1452rnN相/33. 11r相/43. 21x相/90mx定子繞組為三角形接法，試求額定負(fù)載時(shí)的定子電流、轉(zhuǎn)子電流、定子繞組為三角形接法，試求額定負(fù)載時(shí)的定子電流、轉(zhuǎn)子電流、勵(lì)磁電流、功率因數(shù)、輸入功率和效率。勵(lì)磁電流、功率因數(shù)、輸入功率和效率。例例5-15-1一臺(tái)一臺(tái)2對(duì)極的三相異步電動(dòng)機(jī)，有關(guān)數(shù)據(jù)如下：對(duì)極的三相異步電動(dòng)機(jī)，有關(guān)數(shù)據(jù)如下：相/7mr相/4 . 42x相/12.

36、 12r電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT解：解：032. 015001452150000nnnsN35032. 012. 12sr電機(jī)額定運(yùn)行時(shí)轉(zhuǎn)差率為電機(jī)額定運(yùn)行時(shí)轉(zhuǎn)差率為電機(jī)轉(zhuǎn)子電阻（含負(fù)載等效電阻）為電機(jī)轉(zhuǎn)子電阻（含負(fù)載等效電阻）為（1）用）用T形等效電路計(jì)算形等效電路計(jì)算電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepart

37、ment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT轉(zhuǎn)子支路阻抗為：轉(zhuǎn)子支路阻抗為：15. 74 .35)4 . 435(22jx jsr54.854 .90)907(jjxrZmmm)89.136 .27(54.854 .9015. 74 .3554.854 .9015. 74 .35)/()/(2222jZx jsrZx jsrmm43.2923.33)/()/(22221mmZx jsrZx jsrZ勵(lì)磁支路阻抗為：勵(lì)磁支路阻抗為：轉(zhuǎn)子支路和勵(lì)磁支路并聯(lián)阻抗為：轉(zhuǎn)子支路和勵(lì)磁支路并聯(lián)阻

38、抗為：定子支路和（轉(zhuǎn)子支路和勵(lì)磁支路并聯(lián)）的串聯(lián)阻抗為：定子支路和（轉(zhuǎn)子支路和勵(lì)磁支路并聯(lián)）的串聯(lián)阻抗為：電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT設(shè)設(shè) ，定子電流，定子電流VU03801AAZx jsrZx jsrZUImm43.2942.1143.2923.330380)/()/(2222111定子線電流有效值定子線電流有效值A(chǔ)A8 .1942.113定子功率因數(shù)定子功率因數(shù))(8

39、7. 043.29coscos1滯后定子輸入功率定子輸入功率WWIUP1132687. 042.113803cos31111電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUTAAZx jsrZIImm97. 95 .1034 .9042.11)/(2212轉(zhuǎn)子電流轉(zhuǎn)子電流 和勵(lì)磁電流和勵(lì)磁電流2ImIAAZx jsrx jsrIImm91. 35 .1034 .3542.11)/(/22221

40、效率效率%26.88%100113301000012PP電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT（2）用近似等效電路計(jì)算）用近似等效電路計(jì)算負(fù)載支路阻抗負(fù)載支路阻抗6 .101 .37)83. 643.36()4 . 41 .3543. 233. 1 (/221jjjx jsrZ勵(lì)磁支路阻抗勵(lì)磁支路阻抗54.854 .90)907(jjxrZmmm電機(jī)學(xué)電機(jī)學(xué) Electric ma

41、chineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT轉(zhuǎn)子電流（即負(fù)載電流）轉(zhuǎn)子電流（即負(fù)載電流）6 .1024.106 .101 .370380/22112 Ax jsrZUI勵(lì)磁電流勵(lì)磁電流AAZUImm54.852 . 454.854 .9003801定子電流定子電流AAjIIIm1 .2945.12)065. 6396.10(21 定子線電流有效值定子線電流有效值A(chǔ)A6 .2145.123定子功率因數(shù)定子功率因數(shù))(874.

42、 01 .29coscos1滯后電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT定子輸入功率定子輸入功率WWIUP12405874. 045.123803cos31111效率效率%6 .80%100124001000012PP電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFU

43、TDepartment of Electrical Engineering, HFUT第三節(jié)第三節(jié) 三相異步電動(dòng)機(jī)的功率和轉(zhuǎn)矩三相異步電動(dòng)機(jī)的功率和轉(zhuǎn)矩一、功率轉(zhuǎn)換過程一、功率轉(zhuǎn)換過程功率關(guān)系能量轉(zhuǎn)換關(guān)系電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT二、功率方程式二、功率方程式emFeCuPppP1111111cosIUmP 12111rImpCummFerImp21srImIEmPem/

44、cos22212221U1定子相電壓；定子相電壓；I1 定子相電流；定子相電流； 定子功率因數(shù)角；定子功率因數(shù)角； 轉(zhuǎn)子功率因數(shù)角；轉(zhuǎn)子功率因數(shù)角；12電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUTmecCuemPsrImsrImsrImpP2221222122212)1 (2)(PppPmecmecemCusPsrIsmrImp222122212電磁功率分析電磁功率分析emFeCuPpp

45、P11輸入功率定子銅耗定子鐵耗電磁功率輸入功率定子銅耗定子鐵耗電磁功率電磁功率轉(zhuǎn)子銅耗總機(jī)械功率電磁功率轉(zhuǎn)子銅耗總機(jī)械功率總機(jī)械功率機(jī)械損耗功率附加損耗功率輸出機(jī)械功率總機(jī)械功率機(jī)械損耗功率附加損耗功率輸出機(jī)械功率電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT總機(jī)械功率總機(jī)械功率emCuemmecPssrImsrImsrImpPP)1 ()1 (2221222122212?:2mecCue

46、mPpP電磁功率：轉(zhuǎn)子銅耗：總機(jī)械功率電磁功率：轉(zhuǎn)子銅耗：總機(jī)械功率等于多少？等于多少？ssPpPmecCuem1:1:2電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT三、轉(zhuǎn)矩方程式三、轉(zhuǎn)矩方程式022TTTTTTmecem式中式中 電動(dòng)機(jī)輸出的機(jī)械轉(zhuǎn)矩；電動(dòng)機(jī)輸出的機(jī)械轉(zhuǎn)矩； 機(jī)械損耗轉(zhuǎn)矩；機(jī)械損耗轉(zhuǎn)矩； 附加損耗轉(zhuǎn)矩；附加損耗轉(zhuǎn)矩； 空載轉(zhuǎn)矩；空載轉(zhuǎn)矩； 電磁轉(zhuǎn)矩。電磁轉(zhuǎn)矩。2Tmec

47、TT0TemT異步電機(jī)總的機(jī)械轉(zhuǎn)矩（電磁轉(zhuǎn)矩）為：異步電機(jī)總的機(jī)械轉(zhuǎn)矩（電磁轉(zhuǎn)矩）為：0202000)1 ()1 (sppPPPsPsPTcucumecemememmecemmecemPTssPpPmecCuem: )1 ( :1:2電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT四、電磁轉(zhuǎn)矩公式四、電磁轉(zhuǎn)矩公式112022201022,260602cos1NkfEpfpfIEmPTweme

48、m22122111coscos2ICIkNpmTmTmWem21111WTkNpmC 轉(zhuǎn)矩常數(shù)轉(zhuǎn)矩常數(shù)電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT例例5-2 根據(jù)根據(jù)例例5-1中的數(shù)據(jù)，還知道電動(dòng)機(jī)的機(jī)械損耗中的數(shù)據(jù)，還知道電動(dòng)機(jī)的機(jī)械損耗 ，額定負(fù)載時(shí)的附加損耗，額定負(fù)載時(shí)的附加損耗 ，試計(jì)算各種功率和轉(zhuǎn)矩。，試計(jì)算各種功率和轉(zhuǎn)矩。Wpmec100Wp50WWrIpmmFe321791

49、. 33322WWrIpCu33512. 198. 93322222WWrIpCu52033. 142.113321211解解定子和轉(zhuǎn)子的銅耗、及定子鐵耗定子和轉(zhuǎn)子的銅耗、及定子鐵耗電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUTsradsradn/157/601500260200sradsradn/152/6014522602同步角速度同步角速度轉(zhuǎn)子機(jī)械角速度轉(zhuǎn)子機(jī)械角速度總機(jī)械功率總機(jī)械

50、功率WWppPPmecmec10150)5010010000(2電磁功率電磁功率WWpPPCumecem10485)33510150(2負(fù)載制動(dòng)功率負(fù)載制動(dòng)功率mNmNPT79.651521000022空載制動(dòng)功率空載制動(dòng)功率mNmNppTmec99. 01521500電磁轉(zhuǎn)矩電磁轉(zhuǎn)矩mNmNTTTem78.66)99. 079.65(02或者或者mNmNPTemem78.66157104850mNmNPTmecem78.6615210150電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineeri

51、ng, HFUTDepartment of Electrical Engineering, HFUT第四節(jié)第四節(jié) 三相異步電動(dòng)機(jī)的工作特性及其測(cè)取方法三相異步電動(dòng)機(jī)的工作特性及其測(cè)取方法一、工作特性的分析一、工作特性的分析1、轉(zhuǎn)速特性、轉(zhuǎn)速特性)(2Pfn 0)1 (nsn222122212cosIEmRImPPsemcu當(dāng)電機(jī)處于空載運(yùn)行時(shí)，電機(jī)轉(zhuǎn)速接近于同步轉(zhuǎn)速；當(dāng)電機(jī)處于空載運(yùn)行時(shí)，電機(jī)轉(zhuǎn)速接近于同步轉(zhuǎn)速；當(dāng)電機(jī)負(fù)載增加時(shí)，轉(zhuǎn)速略為下降，轉(zhuǎn)子電流加大；當(dāng)電機(jī)負(fù)載增加時(shí)，轉(zhuǎn)速略為下降，轉(zhuǎn)子電流加大；電機(jī)在額定負(fù)載時(shí)轉(zhuǎn)差率為電機(jī)在額定負(fù)載時(shí)轉(zhuǎn)差率為1.55，電機(jī)由空載到額定負(fù)載轉(zhuǎn)，電機(jī)由空載

52、到額定負(fù)載轉(zhuǎn)速變化很小。速變化很小。電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT2、定子電流特性、定子電流特性)(21PfI 根據(jù)電機(jī)磁動(dòng)勢(shì)平衡方程根據(jù)電機(jī)磁動(dòng)勢(shì)平衡方程當(dāng)電機(jī)處于空載運(yùn)行時(shí)，定子電流幾乎全部是勵(lì)磁電流；當(dāng)電機(jī)處于空載運(yùn)行時(shí)，定子電流幾乎全部是勵(lì)磁電流；當(dāng)電機(jī)負(fù)載增加時(shí)，轉(zhuǎn)子電流加大，定子電流也相應(yīng)增加；當(dāng)電機(jī)負(fù)載增加時(shí)，轉(zhuǎn)子電流加大，定子電流也相應(yīng)增加；磁動(dòng)勢(shì)方程式磁動(dòng)

53、勢(shì)方程式mIII21電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT3、功率因數(shù)特性、功率因數(shù)特性)(cos21Pf當(dāng)電機(jī)處于空載運(yùn)行時(shí)，定子電流幾乎全部是勵(lì)磁電流，功率因數(shù)當(dāng)電機(jī)處于空載運(yùn)行時(shí)，定子電流幾乎全部是勵(lì)磁電流，功率因數(shù)很低；很低；當(dāng)電機(jī)負(fù)載增加時(shí)，轉(zhuǎn)子電流加大，定子電流中的有功分量逐漸增當(dāng)電機(jī)負(fù)載增加時(shí)，轉(zhuǎn)子電流加大，定子電流中的有功分量逐漸增大；大；當(dāng)負(fù)載超過額定值時(shí)，轉(zhuǎn)子的

54、功率因數(shù)變小，轉(zhuǎn)子的電流的無功分當(dāng)負(fù)載超過額定值時(shí)，轉(zhuǎn)子的功率因數(shù)變小，轉(zhuǎn)子的電流的無功分量開始增加，功率因數(shù)開始下降。量開始增加，功率因數(shù)開始下降。電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT4、電磁轉(zhuǎn)矩特性、電磁轉(zhuǎn)矩特性)(2PfTem/20PTTem5、效率特性、效率特性)(2PfpppppPPmecCuFeCu2122由于異步電機(jī)在負(fù)載不超過額定值時(shí)，轉(zhuǎn)速變化很小，因此電磁轉(zhuǎn)由于

55、異步電機(jī)在負(fù)載不超過額定值時(shí)，轉(zhuǎn)速變化很小，因此電磁轉(zhuǎn)矩近似和輸出功率矩近似和輸出功率P2成正比。成正比。和變壓器一樣，異步電機(jī)的損耗可以分為不變損耗（鐵耗）和可變和變壓器一樣，異步電機(jī)的損耗可以分為不變損耗（鐵耗）和可變損耗（銅耗）兩個(gè)部分：損耗（銅耗）兩個(gè)部分：當(dāng)電機(jī)空載時(shí)，輸出為零，電機(jī)此時(shí)效率非常低；當(dāng)電機(jī)空載時(shí)，輸出為零，電機(jī)此時(shí)效率非常低；隨著電機(jī)負(fù)載加大，可變損耗開始上升，但相對(duì)輸出功率增加較慢，隨著電機(jī)負(fù)載加大，可變損耗開始上升，但相對(duì)輸出功率增加較慢，電機(jī)效率上升；電機(jī)效率上升；隨著電機(jī)負(fù)載進(jìn)一步加大，可變損耗開始較之輸出功率增加變快，隨著電機(jī)負(fù)載進(jìn)一步加大，可變損耗開始較之

56、輸出功率增加變快，電機(jī)效率開始下降。電機(jī)效率開始下降。電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT二、工作特性的求取二、工作特性的求取工

57、作特性的求取工作特性的求取 可以用直接負(fù)載法，通過做實(shí)驗(yàn)求??；也可以可以用直接負(fù)載法，通過做實(shí)驗(yàn)求??；也可以利用等效電路進(jìn)行計(jì)算。利用等效電路進(jìn)行計(jì)算。電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT第五節(jié)第五節(jié) 三相異步電動(dòng)機(jī)參數(shù)的測(cè)定三相異步電動(dòng)機(jī)參數(shù)的測(cè)定異步電機(jī)中有兩種參數(shù)：異步電機(jī)中有兩種參數(shù)：（1）空載勵(lì)磁參數(shù)：勵(lì)磁電阻、勵(lì)磁電抗、勵(lì)磁阻抗）空載勵(lì)磁參數(shù)：勵(lì)磁電阻、勵(lì)磁電抗、勵(lì)磁

58、阻抗（2）堵轉(zhuǎn)參數(shù)：定子電阻、定子漏抗、轉(zhuǎn)子電阻、轉(zhuǎn)子電抗）堵轉(zhuǎn)參數(shù)：定子電阻、定子漏抗、轉(zhuǎn)子電阻、轉(zhuǎn)子電抗電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT1、空載試驗(yàn)、空載試驗(yàn)試驗(yàn)條件：試驗(yàn)條件：（1）軸上不帶任何負(fù)載；）軸上不帶任何負(fù)載；（2）異步電動(dòng)機(jī)在額定頻率下運(yùn)）異步電動(dòng)機(jī)在額定頻率下運(yùn)行；行；（3）電壓從）電壓從1.11.3倍額定值逐倍額定值逐漸降低，直到轉(zhuǎn)速發(fā)生明顯的變漸降低，

59、直到轉(zhuǎn)速發(fā)生明顯的變化（轉(zhuǎn)差率明顯增大）化（轉(zhuǎn)差率明顯增大）獲得數(shù)據(jù)：獲得數(shù)據(jù)：端電壓、空載電流、空載功率、端電壓、空載電流、空載功率、轉(zhuǎn)速轉(zhuǎn)速一、空載試驗(yàn)及空載時(shí)參數(shù)的確定一、空載試驗(yàn)及空載時(shí)參數(shù)的確定空載特性曲線電機(jī)學(xué)電機(jī)學(xué) Electric machineryElectric machineryDepartment of Electrical Engineering, HFUTDepartment of Electrical Engineering, HFUT2、勵(lì)磁參數(shù)與鐵耗及機(jī)械損耗的確定、勵(lì)磁參數(shù)與鐵耗及機(jī)械損耗的確定異步電機(jī)空載時(shí)，輸入功率補(bǔ)償定異步電機(jī)空載時(shí)，輸入功率補(bǔ)償定子銅耗、鐵耗、機(jī)械損耗：子銅耗、鐵耗、機(jī)械損耗：mechFeppRImP121110鐵耗正比于電壓平方，做出鐵耗與鐵耗正比于電壓平方，做