三相鼠籠異步電動(dòng)機(jī)的工作特性

1、41三相鼠籠異步電動(dòng)機(jī)的工作特性實(shí)驗(yàn)?zāi)康? .掌握三相異步電動(dòng)機(jī)的空載、堵轉(zhuǎn)和負(fù)載試驗(yàn)的方法.2 .用直接負(fù)載法測(cè)取三相鼠籠有電動(dòng)機(jī)的工作特性.3 .測(cè)定三相鼠籠異步電動(dòng)機(jī)的參數(shù).預(yù)習(xí)要點(diǎn)1 .異步電動(dòng)機(jī)的工作特性指哪些特征？2 .異步電動(dòng)機(jī)的等效電路有哪些參數(shù)？它們的物理意義是什么?3 .工作特性和參數(shù)的測(cè)定方法.三、實(shí)驗(yàn)設(shè)備廳PDDSZ-1名稱數(shù)量1DD03導(dǎo)軌、測(cè)速發(fā)電機(jī)及轉(zhuǎn)速表1件2DJ23校正過(guò)的直流電機(jī)1件3DJ16三相鼠籠異步電動(dòng)機(jī)1件4D33交流電壓表1件5D32交流電流表1件6D34-3單三相智能功率、功率因數(shù)表1件7D31直流電壓、毫安、安培表1件8D42三相可調(diào)電阻器1件

2、9D51波形測(cè)試及開關(guān)板1件四、測(cè)量定子繞組的冷態(tài)直流電阻將電機(jī)在室放置一段時(shí)間,用溫度計(jì)測(cè)量電機(jī)繞組端部或鐵心的溫度與冷卻介質(zhì)溫度之差不超過(guò)2K時(shí),即為世紀(jì)冷態(tài).記錄此時(shí)的溫度和測(cè)量定子繞組的直流電阻,此阻值即為冷態(tài)直流電阻.用伏安法測(cè)定子繞組電阻,測(cè)量線路如圖4-1.直流電源用主控屏上電樞電源先調(diào)到50V.開關(guān)S1、S2選用D51掛箱,R用D42掛箱上1800.可調(diào)電阻.圖4-1三相交流繞組電阻測(cè)定量程的選擇：測(cè)量時(shí)通過(guò)的測(cè)量電流應(yīng)小于額定電流的20%,約為50mA,因而直流電流表的量程用200mA檔.三相鼠籠式異步電動(dòng)機(jī)定子一相繞組的電阻約為50Q,因而當(dāng)流過(guò)的電流為50mA時(shí)二端電壓約

3、為2.5V,所以直流電壓表量程用20V檔.按圖4-1接線.把R調(diào)至最大位置,合上開關(guān)S1,調(diào)節(jié)直流電源及R阻值使試驗(yàn)電流不超過(guò)電機(jī)額定電流的20%,以防因試驗(yàn)電流過(guò)大而引起繞組的溫度上升,讀取電流值,再接通開關(guān)S2讀取電壓值.讀完后,先翻開開關(guān)S2,再打開開關(guān)S1.調(diào)節(jié)R使A表分別為50mA,40mA,30mA測(cè)取三次,取其平均值,測(cè)量定子三相繞組的電阻值,采集數(shù)據(jù)：表4-11繞組I繞組II繞組IIII(mA)40503029.9840.0050.1729.9239.9950.11U(V)1.7062.1171.2801.2571.6782.1051.2531.6772.014R(Q)42.6

4、5：42.3442.6741.9341.9541.96：41.8841.94:40.19五、負(fù)載情況(一)針對(duì)DDSZ-1電機(jī)教學(xué)實(shí)驗(yàn)臺(tái)1 .空載實(shí)驗(yàn)(1)按圖4-2接線.電機(jī)繞組為接法(Un=220V),直接與測(cè)速發(fā)電機(jī)同軸聯(lián)接,負(fù)載電機(jī)DJ23不接.(2)把交流調(diào)壓器調(diào)至電壓最小位置,接通電源,逐漸升高電壓,使電機(jī)啟動(dòng)旋轉(zhuǎn),觀察電機(jī)旋轉(zhuǎn)方向.并使電機(jī)旋轉(zhuǎn)方向符合要求(如果轉(zhuǎn)向不符合要求需要調(diào)整相序時(shí),必須切斷電源).使機(jī)械損耗到達(dá)穩(wěn)定后再進(jìn)行(3)保持電動(dòng)機(jī)在額定電壓下空載運(yùn)行數(shù)分鐘,試驗(yàn).圖4-3三相鼠籠式異步電動(dòng)機(jī)試驗(yàn)接線圖(4)保持電動(dòng)機(jī)在額定電壓下空載運(yùn)行數(shù)分鐘,使機(jī)械損耗到達(dá)穩(wěn)定

5、后再進(jìn)行試驗(yàn).(5)調(diào)節(jié)電壓由1.2倍額定電壓開始逐漸降低電壓,直至電流或動(dòng)率顯著增大為止.在這圍讀取空載電壓、空載電流、空載功率.(6)在測(cè)取空載實(shí)驗(yàn)數(shù)據(jù)時(shí),在額定電壓附近多測(cè)幾個(gè)點(diǎn),共取數(shù)據(jù)79組采集于表4-2.表4-2序號(hào)Uol(V)IOL(A)P0(W)COS小UabUbcUcaUolIaIBICIOLPiPP01259.6256259.8258.50.3020.2820.2820.28952.08-24.5227.560.1232249.8245.9249.5248.40.2850.2670.2670.27347.81-22.0025.810.1293228.0224.9228.12

6、270.2570.2390.2400.24540.48-16.6523.830.1434221.6218.6221.9220.70.2480.2300.2340.23738.01-12.5625.450.1625220.4217.4220.4219.40.2460.2300.2370.23837.83-15.0122.820.1466220.0217.4219.8222.80.2450.2290.2300.23537.47-14.8722.60.1447216.2214.2217.0215.80.2400.2250.2290.23136.62-14.3422.280.1498210.1207.

7、9211.0209.70.2340.2160.2220.22434.95-13.2021.750.1549133.8133.4134.7134.00.16490.15370.15870.15916.68-1.0515.630.2451080.4079.0080.8080.10.16540.1530.15190.15712.602.4315.030.3981162.9661.8563.1162.-640.2160.2070.2040.20912.932.8415.770.4021255.1354.2254.8254.720.2900.3870.3850.35417.77-1.4316.340.2

8、812 .短路實(shí)驗(yàn)(1)測(cè)量接線圖同圖4-2,0用制開工具把三相電機(jī)堵住.制開工具可用DD05上的圓盤固定在電機(jī)軸上,螺桿裝在圓盤上.(2)調(diào)壓器退至零,合上交流電源,調(diào)節(jié)調(diào)壓器使之逐漸升壓到短路電流到1.2倍額定電流,再逐漸降壓至0.3倍額定電流為止.(3)在這圍讀取短路電壓、短路電流、短路功率.共讀取56組采集于表4-3表4-3序號(hào)Ukl(V)Ikl(A)Pk(W)COS小KUabUbcUcaUklIa1B1cIklPiPiiiPk175.8674.6375.7575.410.6200.6150.6150.61739.84-0.9738.870.278265.0264.2165.4764.

9、90.5040.4970.5020.50127.55-1.4526.100.266358.9157.4059.1058.470.4380.4250.4310.43127.55-1.4526.100.266450.2849.0450.1249.810.3440.3370.3380.41013.95-1.7712.180.199541.7340.4941.7241.310.2570.2490.2520.2538.35-1.526.830.217633.8533.4735.0534.120.1850.17350.1860.1824.79-1.123.670.197730.0128.7630.0329

10、.600.14460.13570.13750.1393.14-0.862.280.1853 .負(fù)載實(shí)驗(yàn)(1)測(cè)量接線圖如圖4-2.同軸聯(lián)接負(fù)載電機(jī).圖中Rf用D42上1800Q阻值,RL用D42上1800.阻值力口上900.并聯(lián)900Q共2250Q阻值.(2)合上交流電源,調(diào)節(jié)調(diào)壓器使之逐漸升壓至額定電壓保持不變.(3)合上校正過(guò)的直流電機(jī)的勵(lì)磁電源,調(diào)節(jié)勵(lì)磁電流至校正值(50m頌100mA并保持不變.(4)調(diào)節(jié)負(fù)載電阻RL(先調(diào)節(jié)1800Q電阻,調(diào)至零后用導(dǎo)線短接再調(diào)節(jié)450Q電阻),使異步電動(dòng)機(jī)的定子電流逐漸上升,直至電流上升到1.25倍額定電流為止.(5)從這負(fù)載開始,逐漸減小負(fù)載直至空

11、載,在這圍讀取異步電動(dòng)機(jī)的定子電流、輸入功率、轉(zhuǎn)速、直流電機(jī)的負(fù)載電流If等數(shù)據(jù).(6)共取數(shù)據(jù)89組采集于表4-4中表4-4Uh=U1n=220V(A)If=100.4mA序號(hào)Iil(A)Pi(W)1f(A)T2(N*m)N(r/min)1a1bIc1ilPiPiiPi10.6210.6010.5960.606130.949.14180.040.6830.920137820.5050.4850.4820.491106.9335.28142.210.5180.730141130.4550.4420.4300.44295.4527.53122.980.4320.654142440.4060.38

12、60.3850.39285.0220.68105.70.3570.556143850.3310.3070.3080.31566.090.69666.790.2010.390145960.3000.2800.2810.28758.001.1359.130.1350.340146870.2870.2690.270.0.27554.30-1.4552.850.1050.290147180.2770.2590.2560.26451.19-4.0447.150.0770.275147990.2540.2380.2400.24442.15-10.8331.3200.1851485六、實(shí)驗(yàn)報(bào)告1、計(jì)算基準(zhǔn)工

13、作溫度時(shí)的相電阻由實(shí)驗(yàn)直接測(cè)得每相電阻值,此值為實(shí)際冷態(tài)電阻值.冷態(tài)溫度為室按下式換算到基準(zhǔn)工作溫度時(shí)的定子繞組相電阻：溫.235r1refr1C"L235ref式中r1refric-0ref0c-一換算到基準(zhǔn)工作溫度時(shí)定子繞組的相電阻,Q;一定子繞組的實(shí)際冷態(tài)相電阻,Q;-基準(zhǔn)工作溫度,對(duì)于E級(jí)絕緣為75C；實(shí)際冷態(tài)時(shí)定子繞組的溫度,C；2.作空載特性曲線：Iol、Po、COS(|)0=f(Uol)用MATLAB作圖如下:PO=f(UOL)IOL=f(UOL)UOLCOS小0=f(UOL)3.作短路特性曲線：IKL、PK=f(UKL)用MATLAB作圖如下：IKL=f(UKL)IK

14、EUKL)V藕測(cè)1次多項(xiàng)式曲線°iiiiriL2S3.3S40456055BO657075UKLPK=f(UKL)4 .由空載、短路實(shí)驗(yàn)數(shù)據(jù)求異步電機(jī)的等效電路參數(shù)(1)由短路實(shí)驗(yàn)數(shù)據(jù)求短路參數(shù)短路阻抗：短路電阻:Pk短路電抗:式中Uk尸Ukl,Ikl=Ikl/3"Ph-電動(dòng)機(jī)堵轉(zhuǎn)時(shí)的相電壓,相電流,三相短路功率(接法).轉(zhuǎn)子電阻的折合值：式中r1c是沒(méi)有折合得75oC時(shí)實(shí)際值定、轉(zhuǎn)子漏抗：短路參數(shù)短路阻抗ZK(Q)短路電阻rk(q)短路電抗XK(Q)定轉(zhuǎn)子漏抗X1.(Q)數(shù)值211.7102.1185.592.8224.4104.0198.899.4235.0104.02

15、10.7105.4210.472.5197.598.6282.9106.7262.0131.0324.7110.8304.5152.3372.9118.0246.1123.0(2)由空載試驗(yàn)數(shù)據(jù)求激磁回路參數(shù)空載阻抗空載電阻/_吃f0一.空載電抗不-療式中Uo產(chǎn)Uol,Io產(chǎn)Iol/3"5,P0-電動(dòng)機(jī)堵轉(zhuǎn)時(shí)的相電壓,相電流,三相短路功率(接法).激磁電抗激磁電阻空載阻抗Z0(KQ)空載電阻Ro(KQ)空載電阻X0(KQ)激磁電抗Xm(KQ)1.5490.3301.5130.7571.5760.3461.5470.7741.6050.3971.5550.7781.6130.4531.

16、5480.7741.597F0.4031.5450.77311.6420.4091.5900.7951.6180.4181.5630.7821.6210.4331.5620.7811.4600.6181.3230.6620.8840.6100.6400.3200.5190.3610.3730.1870.2680.1300.3440.172式中PFe為額定電壓時(shí)的鐵耗,由圖4-4確定5 .做工作特性曲線P1、|1、刀、S、COSd1=f(P2)由負(fù)載試驗(yàn)數(shù)據(jù)計(jì)算工作特性,填入表4-5中廳P電動(dòng)機(jī)輸入電動(dòng)機(jī)輸出計(jì)算值Iu(A)P1(W)T2(N*m)n(r/min)P2(W)S(%)“(%)cos

17、(|)110.350180.040.9201378133.18.1373.90.76620.283142.210.7301411108.25.9376.10.76130.255122.980.654142497.85.0679.50.73140.226105.70.556143884.04.1379.50.70950.17966.790.390145959.72.7389.40.56560.16659.130.340146852.42.1388.60.54070.15952.850.290147144.81.9384.80.50480.15247.150.275147942.71.4090.6

18、0.47090.14131.320.185148528.81.0092.00.337表4-5Ui=220V(A)If=100.4mA%十左卓計(jì)算公式為,人1500孫八A=0.10和147=xl0(1%式中I定子繞組相電流FA：6定子繞組相電壓,V：S轉(zhuǎn)差率:n效率用MATLAB作圖如下1C網(wǎng)F2)406010012030P220U0=妒20.3I107-2043P21001201406 .由損耗分析法求額定負(fù)載時(shí)的效率電動(dòng)機(jī)的損耗有：鐵耗：PFe機(jī)械損耗：Pcui=3I2i'ri轉(zhuǎn)子銅耗：PcU2=PemS/100雜散損耗Pad取為額定負(fù)載時(shí)輸入功率的0.5%.式中Pem-電磁功率,W;P0'=PFe+Pmec=P0-I2OGr1為了別離鐵耗和機(jī)械損耗,作曲線Po'=f(U20),如圖4-4延長(zhǎng)曲線的直線局部與縱軸相較于K點(diǎn),K點(diǎn)的縱坐標(biāo)即為電動(dòng)機(jī)的機(jī)械損耗Pmec,過(guò)K點(diǎn)作平行于橫軸的直線,可得不同電壓的鐵耗PFeo電機(jī)的總損耗工P=P注+屋,+Pm十月一于是求得額定負(fù)載時(shí)的效率為：6一XPq=