(2)n2=500r/min 因负载转矩不变,所以稳定后电流不变,a2=08I=24(A) U2=En2+2R=0.208×500+24×04=1136(1) (3)=0.85女因负载转矩不变,稳定后电流 ln3=08 N=0.8×30/0.85=28.2(4 220-28.2×0.4 =1180(r/min) Ceφ30.85×0208 (4)U4=0.9UN,4=0.9女N 稳定后电流:l4=08x=0.8×300.9=2667(4 220×0.9-2667×0.4 CeO 1000.7(r/min) 0.9×0.208（2）n2 ＝500r/min， 因负载转矩不变，所以稳定后电流不变，Ia2 ＝0.8IN=24(A) 0.208 500 24 0.4 113.6( ) U2 = Ea2 + I a2 Ra =  +  = V 3 0.85 N (3)  =  因负载转矩不变，稳定后电流 0.8 0.8 30 / 0.85 28.2( ) 3 I 3 I N A N a = =  =   1180( / min) 0.85 0.208 220 28.2 0.4 3 3 3 r Ce E n a =  −  = =  （4）U4 ＝0.9UN, 4 = 0.9 N 稳定后电流： 0.8 0.8 30 / 0.9 26.67( ) 4 I 4 I N A N a = =  =   1000.7( / min) 0.9 0.208 220 0.9 26.67 0.4 4 4 4 r Ce E n a =   −  = = 