294 Mr. E. H. M. Bosanquet on Self-regulating 



bility of a self-regulation by main coils alone, which was 

 pointed out experimentally by me in a former paper (Phil. 

 Mag. xiv. p. 247). 



General case of constant current : 



_ E 2 E 5 



k> 



and E = C(R + rs); 



.-. p = C 2 (R + r S )(l-f-); 

 condition, c= constant, 



The general elimination of r is hardly possible. 

 But taking main coils only, 



p = co, v = 0, s=l, 



p = C 2 (K + r), 



or 



I — l*>v 

 K-j-r 



1 x-l 



p<S x = Q 2 n x l\v, 



2x-\ x-l 



p = C x n * l\v, 



a rectilinear governor as before, which can govern _p = At 2 * in 

 stable motion. 



There can be no doubt that the case of constant current is 

 best dealt with by main coils only. 



The governing function supplying power proportional to 

 the velocity is probably the only example of a simple theo- 

 retical governing function which could be easily realized in a 

 rigorous manner in practice. This would be done, as has been 

 observed already, by a reducing valve, delivering steam in 

 unlimited quantity at constant pressure. 



I will now apply the method up to a certain point to a par- 

 ticular case of the general problem, in which the E.M.F. 

 between armature-brushes is required to be constant. 



= e = constant. 



R + rs 



