< H IV 8HI MOTORS M;, 



It" then the combination !- driv.-n at the proper speed, 

 the generator will give the specified current at the <|H-nti. -1 



Example 26. -A generator has to be tested under 

 the following condition* : The speed i- to !> 78<* r.p.in., 

 the current :I"> nni|ervs. with a tension of 110 volte on 

 the brushes. The resistance of the armature is " "I ..inn. 

 The induced tension of the generator must ! greater 

 than toe tension at the brushes by the amount of the heat- 

 drop, whi< volte at 350 amperes. Hence we have 

 volte as the induced tension, giving 8*73 .*. the 

 indurti..ii t-i. -tor of the jr Inserting this value 

 nation |:|. \\,- tind that the induction factor of the 

 inu-t U- Nl'.i. From Iv | nation JO we see that 

 -.njue re<|uiri-d ?.. make up the heat loss is 

 inch-pounds. Suppose that the dynamometer reading 

 showed a torque input of 7 hi inch-pounds, it would 

 follow that there were trictional losses to be* made up 

 and above the heat losses, amounting to l">" inch-pounds 

 On the a.HNumption that the two machines are 

 in all respects similar, we may then say that the frict ion.nl 

 and other ton|ue lo-* in the generator i* 22-> inch- 

 |x uinds. 



<v the two induction factors ore not equal it i* not 

 strictly accurate to divide the torque loose* equally between 

 the two dynamos. We see that in thi.n cac the induction 

 factors are respectively 8*73 and H-li), showing that there 

 is a difference in the magnetic condition of the t\\., 

 iiuwliineH The difference between the induction factors 

 for a given speed mid current in the generator increase 1 * 

 with the reftiAtance in the t\.. >l\n:imos. 



Thi- inethixl in ,.| .oiirxe ii|tiall\ applicalil< |., tin* 



