38 ELECTRICAL MACHINERY 



placing on the shaft a number of thin discs of iron and 

 clamping them tightly together. The reason for making 

 an armature core in this way, evidently much more difficult 

 and expensive than if a solid piece of cast steel were used, 

 will now be given. 



FJG. 14. A Special Construction of Field Frame. Each pole is made 

 up of two parts, one being about twice as large as the other part. 

 General Electric Company. 



Experiment to show the Advantage of Laminating the 

 Core. Two armature cores, of exactly the same dimensions, 

 were made for an experimental generator. One of the 

 cores was of solid iron and the other was of thin iron plates 

 clamped together; thin paper was put between every other 



