238 Behaviour of Iron under Small Magnetizing Forces. 



The results obtained with this specimen are given in the 

 following tables (I. to IV.). The meanings of the different 

 symbols in the tables are given by 



T = period, 



H = H x [sin cot + h 3 sin 3 (cot — c/> 3 ) + h 5 sin 5 (cot — <j> 6 ) ] , 



B = B x [sin (firf-0) + 6 3 sin 3 (cot-d-fa) -j-b 5 sin 5 (»*-0 — ^ 6 )], 



/V 



B, 



Hi' 



/* = 



B T 



a 



*»» = i/2 . R.M.S. (^), 

 I = Iron loss per c.c. per cycle, 

 E = Calculated eddy-current loss per c.c. per cycle, 



Statical Permeability for different Inductions. 



B 



113 



44-8 



111-7 



171-3 



281-8 



421-2 



603-0 



H 



•0747 



•2452 



•5324 



•7474 



1-0664 



1-3903 



1-7119 



/* 



1520 



182-8 



209-5 



229-2 



264-3 



303-0 



352-2 



A number of the results contained in the tables are shown 

 graphically by means of curves. The wave-form of the 

 magnetizing current is in every case approximately sinu- 

 soidal, and so the results obtained may be taken as typical of 

 a series of induction- waves produced by magnetizing currents 

 of similar wave-form. 



The most important of the characteristics are jul and #, 

 which connect the first harmonic of the induction with that 

 of the magnetic intensity. If the magnetizing current and 

 the flux-waves are assumed sinusoidal, then they will be 

 given by expressions of the form ' 



H =="H sin cot, 



B = B Q 'sm (cot — 0), 



B = /^oH ; 

 and from these, since the- total iron loss per c.c. per cycle is 



it follows that 



..KJ. 



EUB, 



I— I^sm0. 

 4 



Thus when /* and are given in terms of B , the behaviour 

 of the iron is determined. 



