CHAPTER II 



PARTS OF A DYNAMO-ELECTRIC MACHINE FUNCTION 

 MATERIAL, CONSTRUCTION 



A dymano electric machine is a machine for converting 

 mechanical energy into electrical energy or vice versa. It may 

 be either a continuous current machine* or an alternating 

 current machine. In the first part of this text we shall 

 deal only with c-c. (abbreviation for continuous current) 

 machines. A general classification of the parts of any c-c. 

 dynamo electric machine may be made as follows: 



(1) Field Frame; (2) Armature Core; (3) Commutator; 

 (4) Brushes and Brush Rigging; (5) Field Windings; (6) 

 Armature Windings. Each of these will be taken up 

 separately, giving reasons for the different forms seen 

 on various commercial machines, and showing why certain 

 materials are preferable to others. 



13. Field Frame. Fig. 3 represents the magnetic circuit 

 of a simple bipolar machine and Fig. 4 shows the magnetic 

 circuit of a multipolar machine. By the term field frame 

 we mean that part of the magnetic circuit made up of 

 the yoke and poles (and pole shoes if there are any). In 

 continuous current machines that part of the magnetic 

 circuit constituting the field frame is stationary, while that 



* In speaking of machines for use in circuits where the current is 

 uni-directional and non-varying the words direct-current and continuous- 

 current are both used; either is correct and they are generally used 

 synonymously we shall use the term continuous-current as it seems 

 to describe the nature of the current better than the term direct- 

 current. 



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