Resistance, and Self- Capacity of Magneto Windings. 55 



and effective resistance of the primary are decreased. Both 

 of these effects are due to the demagnetizing influence of the 

 current induced in the short-circuited coil. The "decrease" 

 in effective resistance is due to the decreased iron loss caused 



Fig-. 15. — (a) Pictorial representation of armature before primary and 

 secondary are wound. 

 (b) Illustrating electric circuits completed by the brass 

 end-plates and the iron plates riveted thereto. 



iron 



plate 



by the smaller variation in flux density resulting fromf the 

 demagnetizing action of the coil — i. e., transformer action. 

 With an air-cored coil the external inductance decreases, 

 but the copper loss increases owing to ohmic lossdue tothe 

 currents in the secondary exploring coil. Thus with the iron 

 core in place, although the total effective resistance (iron 



