1 3 1/3 1/3 yes no -22-19 wye-delta -22-20 auto- 2 2 - PowerPoint PPT Presentation

IEV 411 Starting winding mains current % torque % interruption starting time critical method current % -22-18 direct - - - no no -22-26 series-parallel 1/2 1/4 1/4 yes no 1 ⁄ √ 3 1/3 1/3 yes no -22-19 wye-delta -22-20 auto- α α 2 α 2 transformer -22-21 with 2 α α 2 α 2 yes no switches -22-22 with 3 α α 2 α 2 no no switches -22-23 stator α α α 2 no yes inductance -22-25 stator α α α 2 no yes resistance Table 1 Classical starting methods

R 1 jX 1 � jX' 2 � R' 2 /s jX � R /s (r 1 ) (jx 1 � ) (jx 2 � ) (r 2 /s) (jx � ) (r /s) + I 1 + + I 1 I' 2 I (i 1 ) (i 1 ) jX ml (i 2 ) (i ) V 1 jX m E 1 (jx ml ) V 1 I m (b) (a) (v 1 ) (jx m ) (i m ) (v 1 ) I ml _ _ (i ml ) _ X = X + X = (1+ )X = X � m l ml l ml l � � 2 X X = X (1+ )+X' (1+ ) = � � l l l 2 l � � � 1 � � 2 R = (1+ ) R' � l 2 I = ' /(1+ ) I � 2 l

t i l v l 3 i m i l i 2 1 1 1 s/r x � (a) (b)

t t po 0 1 2 t max n-1 n t min 0 = / � � � r r sy 0 s 2 s 1 s n s o s s =1 n+1

r =0,05 r =0,05 2 2 E 0,05 0,15 0,35 0,05 D 0,1 0,7 1,4 2,8 C 0,2 (b) (c) B 0,4 A 0,8 (a)

2 t 1 0 1 0,5 0 s

� r R u R u R u w � r (a) (b)

sy � � / r = r � 1 r r ��� 2r r Ia 4r r 8r r -1 1 0 r r t ��� ��� 2r r III 4r r 16r r 4r r 2r r r r 20r r ��� -1 24r r Ib II 32r r

1 > > 0 0 > � � l > s > : motoring l > s > : motoring � � P em1 P em1 P 2 sP em1 � P em1 (here s < 0) � P em1 P =(s- )P � j2 em1 (1-s)P em1 (1-s)P em1 P =(s- )P � j2 em1 P 2 P m P m s > 1 > : reverse braking s > 1 > 0 > : reverse braking � � P em1 P em1 � P em1 eml P 2 (s- )P sP em1 � P j2 (1-s)P eml � P eml (1-s)P em1 P =(s- )P � j2 em1 P m P m P 2 � > s : generating 0 > > s : generating � P em1 P em1 P =(s- )P P j2 � j2 em1 P 2 � P em1 (s- )P � em1 P em1 sP em1 (here s > 0) � P em1 (1-s)P em1 (1-s)P em1 P em1 P 2 sP eml P m P m positive sign references : : P =(s- )P � (URS primary, GRS secondary) j2 em1 P 2 �� P em1 (1-s)P em1

E g E m ��� E =K. . ���� � (1-s) g sy adjustable E = k.E = k.s.E' m 2 1 DC source � = � � / r r sy 0 0 1 0 1 s s 0 (b) (a)

(c) (0) (a) 1 2 0 1 � s -1 2 0 1 ������ (b) ����� ��� ����� P <0 P <0 P <0 P >0 m m m m P >0 P <0 P <0 P >0 eml eml eml eml P >0 P <0 P <0 P >0 2 2 2 2 s 2 (P >0) (P <0) (P >0) (P >0) em2 em2 em2 em2 1> >0 � reverse braking motor generator � 0 1 P >0 P <0 P <0 P >0 m m m m P >0 P >0 P <0 P >0 eml eml eml eml P <0 P <0 P >0 P <0 2 2 2 2 2 (P >0) (P >0) (P >0) s (P <0) em2 em2 em2 em2 0> � � motor generator reverse braking 1 motor 0

� r � r w � r w � r (a) ( c) (b)

slip energy conversion 50Hz (a) (b)