178 



Prof. J. Perrv on the 



that this law is wonderfully true for all loads. From what I 

 have already said, it is. obviously the rule whatever function 

 of the time the current may be, if it is rapidly alternating. 

 That is, 



S 

 Effective Secondary _ Effective Primary P P n q\ 



Voltage Voltage X g 2 ' 



R + p + R p^ 



In practice it is found that the secondary voltage " drops " 

 more rapidly than this law would indicate — a result which 

 might have been expected, as we know that there always is 

 leakage. 



May 26th. — When the above paper was being prepared in 

 February last, not for publication, but to be handed about 

 among my students to connect the results of their calculations, 

 I asked some of them to repeat their calculations on the 

 assumption that there may be magnetic leakage. That is, 

 taking the same values of all their coil quantities as before, 

 assuming that there may be a little magnetic leakage. I did 

 not expect very great differences from the old numbers, but 

 to my astonishment there were very great differences. 



Thus, taking R=10 ohms, B'=\L + p, a=1000 volts, 

 L = 15 secohms, ^ = '15 secohm, two students have worked 

 out what is the effect of magnetic leakage, 1st, when the 

 frequency is 106 per second ; 2nd, when the frequency is 

 10*6 per second. In the first case, two tables were calcu- 

 lated ; in the second case, four. 



No general mathematical expressions will show so forcibly 

 the necessity for caution in neglecting leakage. 



Frequency 106 per second. M=l*50. 

 No magnetic leakage. (Mr. Eliott*) 



p. 



A. 



A'. 



e. 



e'. 



a'. 



P. 



P'. 



E. 







CO 



•1000 







89-9 



1799394 



100 



•0850 







99-9 



♦1412 



•9991 



44-97 



179-9395 



99-82 



50-06 



49-85 



99-59 



499 



■2232 



1-9965 



26-5 



1799395 



99-61 



99-95 



99-45 



99-49 



9-9 



•9956 



9-913 



005 



179-9401 



99-14 



497-8 



486-4 



97-70 



4-9 



1-9630 



19-61 







179-9409 



9608 



981-7 



942-3 



95-98 



0-9 



9-09 



90-95 







179-9168 



81-85 



4545 



3722 



81-70 



04 



16-67 ! 



16(r6 







179-9519 



66-64 



8335 



5551 



66-61 



01 



33-33 



333-3 







1799610 



33-33 



16667 



5554 



33-33 







50 



500 







179-9708 







25000 











