Resistance, and Self- Capacity of Magneto Windings. 



id 



As the time increases from the instant the condenser 

 discharges, the vectors are to be imagined to rotate with 

 angular speed co and shrink in accordance with the damping 

 factor e~ xt . They also preserve the same relative angular 

 displacements as those shown in fig. 21. 



-Fig. 21. — Vector diagram showing phase relations of voltages in circuit 

 of tig. 20. Tl=V c in magnitude and the vector sum of 

 the two is Vr. When Y r is zero or very small, 6— tt/2 and 

 Vl and X c are equal and opposite. 



It is clear that there is a difference in the definition of 

 the terms L e and K e , if not in actual value, from that for 

 undamped oscillations of the same frequency (see fig. 1). 

 The experimental work to obtain the values of the above 

 quantities for a magneto under actual conditions is extremely 

 difficult, owing to the small amount of energy available and 

 the very high damping. 



(14) Measurement of the Effective Inductance and Effectia 

 Resistance under Damped Oscillations. 



We will now examine a peculiar result obtained by 

 Dr. Campbell and mentioned in his paper (see p. 385, 

 loc. cit.). Using an oscillation method (damped oscillations) 

 of determining the primary inductance, he obtained a 

 value of 6'23 X 10~ 3 henry. On inserting an air-cored coil 

 of lxl0~ 3 henry in series with the primary, the self- 

 inductance was reduced to 5*78 x 10~ 3 . This is, of course, 

 a physical impossibility since the total inductance should 

 be 7*23 X 10~ 3 henry. The apparent paradox can bo 



