Resistance, and Self- Capacity of Magneto Windings. 53 

 (c) Effect of Polarization. - 



In Phil. Trans. A, vol. 184 (1893), Ewing and Klaassen 

 showed when a sample of iron was subjected to a magnetizing 

 force produced by a constant current, and therefore causing 

 polarization, that the hysteresis loss resulting from a super- 

 posed force varying between definite limits, decreased with 



Fig, 14, — Variation in effective resistance of secondary with frequency. 



/ 

 30x10^ *■ — 





5x!0 



__300p 



Z000 4000 6000 6000 10000 



Frequency -v. per second. 



Curve 1 = Effective resistance of secondary in housing, with mag-net 

 and brass end-plates ; after fall advance break. 



Curve 2 = Effective resistance with armature removed from housing'. 

 Intercept on vertical axis = res. of secondary at zero frequency =1900 w. 



increase in the polarizing force. This is due to the constraint 

 of the molecular magnets and the consequent diminution in 

 the variation of the flux density. Owing to the latter effect 

 the eddy-current loss is also diminished. 



In the magneto the effect of polarization is clearly exhibited 

 by curves (1) and (2) in figs. 10 and 11 *. These wore 



* During the experiments the rotor was moved slightly beyond us 

 position at advance break in order to show the polarization effect more 

 clearly. 



