PROBLEMS. 57 



APPENDIX C. ARMATURE WINDINGS. 



218. Draw a 2 -pole drum armature winding having 18 induc- 

 tors ; front pitch 7, back pitch 9, showing connections to com- 

 mutator bars. Make the armature circle 4 inches in diameter. 

 Indicate back connections by dotted lines and front connections 

 by full lines, as shown in Fig. 54, Appendix C. 



219. Draw a simplex lap winding for a 4-pole drum armature 

 having 18 inductors ; front pitch 5, back pitch 3. Show connec- 

 tions to commutator bars and indicate positions of poles and 

 brushes. Make the drawing same size and style as Fig. 56, 

 Appendix C. 



220. Draw a simplex wave winding for a 4-pole drum arma- 

 ture having 18 inductors; front pitch 5, back pitch 3. Show 

 connections to commutator bars and indicate positions of poles 

 and brushes. Make the drawing same size and style as Fig. 57, 

 Appendix C. 



221. Draw a doubly reentrant duplex lap winding for a 4-pole 

 drum armature having 36 inductors ; front pitch 10, back pitch 6. 

 Show connections to commutator bars and indicate positions of 

 poles and brushes. Make the drawing same size and style as 

 Fig. 58, Appendix C. 



Note. A duplex lap or wave winding must have both front and back pitches 

 even, when all even numbered inductors belong to the one and all odd numbered 

 inductors belong to the other of the two constituent simplex windings. 



222. Draw a doubly reentrant duplex wave winding for a 4-pole 

 drum armature having 36 inductors ; front pitch 10 and back 

 pitch 6. Show connections to commutator bars and indicate posi- 

 tions of poles and brushes. Make the drawing same size and 

 style as Fig. 59, Appendix C. 



223. Draw a singly reentrant duplex lap winding for a 4-pole 

 drum armature having 34 inductors ; front pitch 7 and back 

 pitch 1 1 . Show connections to commutator bars and indicate 

 positions of poles and brushes. Make drawing same size and 

 style as Fig. 60, Appendix C. 



