PARTS OF A DYNAMO-ELECTRIC MACHINE 37 



in two parts and each part is wound separately. These 

 machines may also be fitted with commutating poles but 

 generally do not require them. An auxiliary pole converter 

 without commutating poles is shown in Fig. 14. 



14. Armature Core. As previously stated the magnetic 

 circuit of any dynamo-electric machine may be considered 

 as made up of two parts, one of which moves with respect 

 to the other. The field frame, carrying the field windings 



FIG. 13. General View of a Field Frame to Show Commutating 

 Poles. The field coils have been removed from one main pole 

 and one commutating pole, to show the relative sizes of the two 

 poles. General Electric Company. 



has already been discussed; the other part of the magnetic 

 circuit is called the armature core. On this part of the 

 magnetic circuit are placed the conductors which serve to 

 generate the e.m.f. (if the machine is a generator) or to 

 carry the current by which torque is developed (if the 

 machine is a motor) . 



Lamination of Core. The armature core is always 

 made of laminated iron, that is, the core is built up by 



