Resistance, and Self- Capacity of Magneto Windings. 49 



It will be observed from fig. 11 that the rate of increase of 

 the primary effective resistance diminishes slightly with the 

 frequency, although it is nearly constant up to 10,000 ~ per 

 second. This is due, of course, to the behaviour of the iron 



Fig'. 10. — Curves showing variation in primary inductance, 

 under different conditions, with frequency. 



5-0 



5x!0 



10 15 ?.0 25 



Frequency — . per second. 



20 



35x!Q- 



Curve 1 = Primary Inductance with iron unpolarized, i. e. magnet 

 removed, after full advance. Coil with brass end-plates, 

 and in housing. 



Curve 2 = As in Curve 1 but with magnet in place, i. e. iron polarized. 



Curve 3 = Primary Inductance with armature removed from housing. 



Points thus : □ = As in Curve 1, but before advance break. 



resulting from the screening effect of eddy currents. The 

 power factor of the primary winding is illustrated by the 

 curve of fig. 13. It increases rapidly until /=5000 ^ and 

 afterwards at a much slower rate, until at /= 15,000 ~ it is 

 Phil. Mag. S. 6. Vol. 41. No. 241. Jan. 1921. E 



