THE CONTINUOUS CURRENT GENERATOR 125 



into the pole tips, so that there are in the pole tip only half 

 as many laminations as there are in the pole itself; such 

 a construction is shown in Fig. 78. This construction 

 tends to give saturated pole tips and consequently a field 

 that is not easily distorted; such a field is said to be a 

 " stiff " field. 



Compensation of Armature Reaction. The magnetizing 

 effect of the armature coils may be neutralized by a com- 

 pensating winding. This consists of a winding imbedded 

 in slots in the pole faces, the winding having one half as 

 many turns as there are turns on the armature. These 



FIG. 79. Location of a Compensating Winding. 



conductors in the pole faces are put in series with the 

 armature so that they carry the same current as the armature, 

 but the connection is so made that every conductor in the 

 compensating winding carries current in the opposite 

 direction to an adjacent conductor on the armature. Fig. 

 79 shows how these conductors are placed in the pole face 

 and the relative direction of the current in the armature 

 and the compensating winding. The compensating wind- 

 ing is very little used; it makes a machine costly to build 

 and a machine without compensating winding, but equipped 

 with properly designed commutating poles, operates just 

 as well. 



