MAGNETIC OKSKiX OK IJKLAVS 



27 



Fig. 2 



NI, NI2 



ABAMPERE TURNS, NI > 



Energy relations in magnetization. 



size, or winding space provided. The choice of these dimensions reflects 

 an economic balance between the manufacturing costs of the magnet and 

 its coil, which increase with these chmensions, and the saxings in power 

 cost resulting from increasing the coil constant. 



2 MAGXETIZATIOX RELATIONS 



The magnetization relations of an (electromagnet define the steady 

 state flux linkages of the coil as a function of the two variables: mag- 

 netomotive force JF (equal to 4xA^/), and the gap .v, which specifies the 

 armature position. They may be represented by a family of curves each 

 gi\'ing the average flux linked per turn plotted against NI for a particu- 

 lai- value of x. In Fig. 2, the curves marked .ri and .7:2 represent two such 

 curves, where Xo corresponds to a smaller gap than .ri . 



To determine how the magnetization relations depend upon the dimen- 

 sions and configuration of the electromagnet reriuires thcii- iii1('rj)retation 

 in terms of static field theory. Such interpretation is needed in deter- 



