ui. i\ siirxT-worxii MMI. 77 



Tlie expenditur- this current passing 



in the two dynamo* can be calculated, since we know tin* 

 resistances. \N timl that th.- ' // loss in .1 is :,;!> , 

 and in /' in . making a total of I ."_'7 watts. 



This loss has to be made up by th.- mechanical input 

 represented by the u/njui-. ami given 1>\ the intercept ./// 

 of combined torque on the speed axis. 



It' in the equation for the torque /=1'H . M we put 



f..r M its equivalent . we can write this equation thus. 



/= I'll . where / is the mechanical watt output or input 



according to -ii/n. Inserting the values of ir and n as 

 found aliove. we timl the corresponding torque to be 

 'in inch-pounds. 



The required torque may be determined in yet another 

 way. The torque in I. due to 21 -2 amperes wh.-n 

 th. induction factor is i. i- 17 1 .'-.". inch-pounds; this t4)nju.- 

 resists the motion. The ton|u- in /', due to the same 

 current, when the induction factor is -1, is II'.' incli- 

 l*>un<U ; this t-njue assists the motion. For uniform 

 i the iLHMinting and resisting torques must be equal, 

 so that we require a torque of (><> in< h-jMninds to assiM the 

 motion, and this must be supplied from some ext 

 source. 



Th' luv Ijeen made that the <>nly t.-nju. 



to be considered are thone tl ue to the current- pa-Mni; in 

 the two dynamos, sod that if the difference between the 

 stilting and retarding torques be supplied from 

 we shall have uniform motion. In practice we cannot 

 run tw.i dynamos in thin manner wit limit experiei 

 a further resisting torque, due to ti in the 





