MAGNETIC PROPERTIES OF PERMINVAR 



25 



Another property of the perminvar alloy closely related to the 

 constancy of permeability is the extremely small hysteresis loss in 

 the range of magnetizing forces and flux densities in which the perme- 

 ability is constant. This is illustrated in Fig. 2 where line a represents 

 the plot of the upper half of the hysteresis loop for a maximum flux 



7000 



6000 



5000 



>- 



m 



< 4000 

 LU 



Ijj 



CL 



3000 



2000 



1000 



Fig. 1- 



12 3 4 5 



H 



-Permeability curves for Armco iron and Perminvar 



(45% Ni— 25% Co— 30% Fe) 



density of approximately 600 gauss. Curves h and c are similar plots 

 for silicon steel (3| per cent silicon) and Armco iron respectively. 

 While the hysteresis loops for Armco iron and silicon steel have con- 

 siderable areas amounting to ZZ and 14 ergs per cubic centimeter per 

 cycle respectively, there is no measurable area for the perminvar 

 alloy. Although the ballistic method of measurements which was 



