电机及拖动课后答案1-5 解:cm /A 98H ,T 1002.0002.0A B ====φ(1) (1) F=Hl=98A/cm´30cm=2940A;I=F/N=2940/1000=2.94A. (2) 此时,F 总=H 铁l 铁+H d d其中:H 铁l 铁=98A/cm´29.9cm=2930.2A;H d d=d´B/m 0=0.001/(4p´10-7)=795.8A;所以:F 总=2930.2+795.8=3726A1-6 解:(1);5.199sin Z x ;1407.0200cos Z r 2005.0100Z 1111111ΩϕΩϕΩ===⨯====(2);66.8sin Z x ;55.010cos Z r 1010100Z 1221222ΩϕΩϕΩ===⨯====1-7 解:每匝电势为:匝744884.036N ;V 4884.00022.05044.4f 44.4e m 1===⨯⨯==φ2-13 解:作直线运动的总质量为:Kg 63966.128022m )1m m (2m =⨯⨯+++⨯=总转动惯量为:222L m kg 63964D m m J ⋅=⨯==总ρ 系统折算后总转动惯量为:2M 2mL eq m kg 74.49J i J J 2J J ⋅=+++=总负载静转矩为:Nm 127792/D g )Hq m (T 2L =⨯⨯+=折算后负载转矩为:Nm 710i T T L'L ==η转速加速度等于:5.95dt dv D 60i dt dn i dt dn m ===π由运动方程的启动转矩:Nm4.12075.9555.974.49710dt dn 55.9J T T eq 'L k =⨯+=+=3-12 解:因为:n 60NpE a φ=(1)单叠:a=2;6004.02602N 230⨯⨯⨯⨯=; N=5750。
(2)单波:a=1;6004.01602N 230⨯⨯⨯⨯=; N=2875。
3-13 解:1y ;5y ;5.5p 2Zk 1====τ3-14 解:A 341U P I ;KW 3.83P P NNN NN1====η 3-15 解:A 700U P I ;KW 1.161P P N1N NN1====ηNm 955n P 55.9T N NN =⨯=3-19 解:负载运行时:V5.11085200260E a =⨯=电压方程为:A 035.2I );3.450(I 5.110a a =+= 负载功率为:W 207R I P L 2a 2==3-21 解:A 8.70I I I ;A 53.1R UI f N a f f =+===V 239R I U E a a N a =+=W 351R I p ;W 642R I p f 2f cuf a 2a cua =⨯==⨯=W16921I E P ;KW 08.18P P a a em NN1====ηW 1159P P p em 10=-=Nm 9.6T T T Nm101nP 55.9T ;Nm 9.107n P 55.9T em 10emem 11=-==⨯==⨯=3-24 解:%5.82P P ;W 6666I U P 12N N 1====ηNm5.17n P 55.9T N NN =⨯=4-6 解:(1)额定附加电阻:Ω455.43.14I U R fNfNr =-=(2)额定运行电枢电压方程: 220=E aN +630´0.0127; E aN =212V额定电磁转矩为:Nm 1700n P 55.9T emem =⨯= 额定输出转矩为:Nm1592n P 55.9T 22=⨯=(3)电机的理想空载转速:rpm 778n E U C U n N aNNN e N 0=⨯==φ4-8 解:额定时:V89.196I P E ;KW 3.17p P P ;A 865.87I I I aN emNaN 0N emN fN N aN ===+==-=(1)电压方程为:220=196.89+87.865´R a ; R a =0.263欧(2)额定电磁转矩:Nm 14.110n P 55.9T emNemN =⨯=(3)P 1=19800W ;h=85.86%(4)A 524.1I T T I ;Nm 91.1n p 55.9T aN emN 00a 00=⨯==⨯=由电压方程得空载电势为:E a0=219.6V空载转速为:rpm 1673n E E n N aN 0a 0=⨯=4-9 解:发电机时电枢电压方程为:V 540R I U E a a ag =+=电动机时电枢电压方程为:V 160R I U E a a am=-=(1)电动机的转速为:rpm 296n E E n g ag am=⨯=(2)由于电枢电流为额定值,所以由电枢电压方程可知,电势E 不变; 磁通之比等于转速的反比,即296/1000=0.296; 电磁转矩之比与磁通之比相等。
4-10 解:额定时电枢电压方程为:V 68.212E ;R I E U aN a aN aN N =+= %3.88%100P P W67987R I I U P Nm5.46T T T Nm5731000600055.9T Nm5.619100030568.21255.9T )1(12f 2fN N N 12emN 02emN =⨯==+==-==⨯==⨯⨯=η1.30I I k :;A 7.9166R U I :)2(N ka N k ====启动电流倍数66.13I I k :;A 7.4166024.0100I :)3(N k ''k '====启动电流倍数4-11 解:提升时电枢电压方程为:V 8.208E ;R I E U a a a aN N =+=下放是利用倒拉反转:n=-300rpm; 此时:E a ’=(-300/795)´208.8=-78.79V 由于负载不变,所以I a 不变等于350A 。
此时电枢电压方程为:)R 032.0(35079.78220c +⨯+-=所以电枢串入电阻为:0.822欧。
4-12 解:空载时电枢铜耗很小,可以忽略,所以空载功率为: p 0=220´0.08=17.6W ;(1)电磁功率为:185+17.6=202.6W; 电磁转矩为:9.55´202.6/1600=1.21Nm Ω31.31R ;R I P UI :)2(a a a em a =+=功率方程(3) 由电枢电压方程可计算出空载和额定时E : E a0=217.5V; E aN =185.9V 。
所以,空载转速为:1872rpm 。
(4)A 592.0I T T I Nm 6571.0T T T Nm 105.016006.1755.9T Nm 5521.0160018555.95.0T 5.0T aN emNema 02em 0N 2=⨯==+==⨯==⨯⨯==n=1400rpm 时,E a =185.9´1400/1600=162.7V 由电压方程得:220=162.7+0.592´(31.31+R); 所以电枢串入电阻为:65.5欧(5)由于负载转矩额定,所以电枢电流额定=1.09A; 由电压方程得:220=E a +1.09´(50+31.31); E a =131.4V所以转速为:n=1600´131.4/185.9=1131rpm。
(6)%6.49W 264I U P ;W 131P n nP N N 1N N2====⨯=η 4-13 解:并励电动机额定时:V4.201354.061.52220E ;A 61.52178.179.53I A79.5322011834U P I ,W 11834P P aN aNN N 1N N NN 1=⨯-==-======η制动瞬间转速未变,电势未变,此时电压方程为:0=201.4+I a (0.354+0.5); I a = -235.8A 。
Nm46.67150061.524.20155.9I E T NaNaN emN =⨯⨯==Ω制动瞬间转矩为:Nm 3.30246.6761.528.235T I I T emN aN a em -=⨯-=⨯=4-14 解:(1)磁路不饱和时,T em 正比于I a ,负载不变时,I a 也不变为额定的40A 。
E aN =220-40´0.55=198V;串电阻后:E a =220-40´(0.55+2)=118V; 所以转速变为:n=1000´118/198=596rpm。
(2)转速变为500rpm 时:E a =198´500/1000=99V。
所以电压为:U=99+40´0.55=121V4-16 解:%;84P P ;A 9.39I I I 12N fN N aN ===-=η;W 3.150I U p ;Nm 9.23n P 55.9T fN N cuf NN2=⨯==⨯=;W 339R I p a 2a cua =⨯=;W 943P P p ;W 8443p p P P 2em 0cua cuf 1em =-==--=;Nm 9.26T T T ;Nm 3n p 55.9T 20em N0=+==⨯=4-17 解:并励电动机额定时: I aN =58 -110/138=57.2A;E aN =110 – 57.2´0.15=101.4V;Nm68.3714702.574.10155.9I E T NaNaN emN =⨯⨯==Ω(1) (1) 串电阻瞬间转速未变,电势未变为101.4V ; 此时电压方程为:110=101.4+I a (0.15+0.5) I a =13.23A;Nm 7.868.372.5723.13T I I T emN aN a em =⨯=⨯=(2) (2) 串电阻稳定后,负载额定,所以电枢电流额定;此时电压方程为:110= E a +57.2(0.15+0.5) E a =72.82V;串电阻稳定后转速变为:n=1470´72.82/101.4=1056rpm 4-18解:(1)磁通为额定的0.85时:1)变化瞬间转速未变,E a =0.85´101.4=86.2V 此时电压方程为:110=86.2+I a ´0.15;I a =158.7ANm 8.8868.372.577.15885.0I C T a 'T em =⨯⨯==φ2)稳定后,负载额定不变,I a =57.2/0.85=67.3A此时电压方程为:110=E a + 67.3´0.15;E a =99.9Arpm 1704n E E n 'NNN aN a =⋅⋅=φφ(2)电压为80V 时,励磁电压也为80V ;因此磁路不饱和时,磁通变为额定的80/110=0.723时;1)变化瞬间转速未变,E a =0.723´101.4=73.3V 此时电压方程为:80=73.3+I a ´0.15;I a =44.6ANm 23.2168.372.576.44723.0I C T a 'T em =⨯⨯==φ2)稳定后,负载额定不变,I a =57.2/0.723=79.1A 此时电压方程为:80=E a + 79.1´0.15;E a =68.13Vrpm 1366n E E n 'NNN aN a =⋅⋅=φφ4-19 解:额定时,电压方程为:220=E a + 68.7´0.224;E a =204.6Vn 0=1500´220/204.6=1613rpm(1) 0.3=(1613-n min )/1613 n min =1129rpm (2) D=1500/1129=1.33;(3) (3) 最低转速时:E a =204.6´1129/1500=154V; 此时电压方程为:220=154+68.7(0.224+R c ); R c =0.737; (4) P 1=220´68.7=15114W; P 2=13000´1129/1500=9785W; p Rc =68.72´0.737=3478W 5-5 解:k=21U• m •φ5-6解:此时E1与f2211U E E U ••••==5-7 解:1) E 2=U 2=110V; 2)如右图示.。