Electro-Motive Force and Current Curves. 



151 



An Analysis of the Electro- Motive Force and Current 

 Curves of a Wilde Alternator, under various con- 

 ditions. By Julius Frith, Heginbottom Physical 

 Scholar of the Owens College. Communicated by 

 Arthur Schuster, Ph.D., F.R.S. 



(Received March 20th, 1894..) 



These experiments were undertaken with a view to find- 

 ing out how far the actual behaviour of an alternating- 

 current dynamo follows the laws deduced for it from the 

 theory of the alternator ; and if the electro-motive force and 

 current deviate from the theoretical sine curve, how many 

 terms of the Fourier's expression should be taken into 



account. They have led to the conclusion that, for the case 

 of an alternator whose armature contains iron, at least 

 three terms of the Fourier's expression must be considered, 



