ELEMENTS OF ELECTRICAL ENGINEERING. 



TABLE. 



Summary for Drum Windings. 



52. Typical examples of drum windings. The following 

 figures, namely, Figs. 56, 57, 58, 59 and 60, show typical ex- 

 amples of drum windings. In these figures the short radial 

 numbered lines represent the inductors, the crossed lines outside 

 of the circle of inductors represent the connections at the back 

 end of the armature, and the crossed lines between the circle of 

 inductors and the commutator at the center represent the connec- 

 tions at the front end of the armature. 



In these figures a small number of armature inductors is 

 chosen for the sake of simplicity, and it is to be noted that for a 

 given number of armature inductors, Z, several different com- 

 binations of front and back pitches are permissible for a given 

 type of winding, especially when Z is a large number as it 

 usually is in actual machines. Furthermore a change of a few 

 units in the value of Z opens up a greatly increased choice of 

 pitches for a given type of winding. Therefore the examples of 

 windings shown in Figs. 56-60 should be looked upon as special 

 cases chosen from among a great number of possible cases. 



