I UK I MM i I !"N I \ I "I: .'-I 



the main *baft. IHMIO- in ordrr to allow for tin* tvni* 

 to motion of the motor shaft anil the glaring, we must 

 increase the 8,000 inch-pound- >n the main -hnft )>y (.<><><> 

 inch-pounds. We might, of course, reduce all resistances to 

 ton |ue measured at tin- motor -haft ; should th-n have 

 to multiply j. l>y i . With an induction factor of " 1 . the 

 current required to overcome the whole resistance would 

 now be 300 amperes; the speed *>f th.- motor would th.-n 

 I-- 1.17" revolutions jx-r minute. To get tin- >|H-ci!i.-d 

 speed we must calculat.- the value of If again : \\. find it 

 to be G-90, and the cunvnt t< be 308 amperes. 



If, in any of the equations for the induction factor, the 

 expression under th.- -ijuare mot should be n- 

 solution of th<- |ii:ttion is impoftsible. This simply 

 states in another way what we have already found, 

 namely, that for any motor there is a certain maximum 

 rate of working that cannot U -xc.-. d.-d. Thi- maximum 

 we found to be one fourth of th<- maximum possible 



watts from the line, or " ' There are three ways of 



putting the limitintr condition. 



, 1 JB 

 ed 



I u 



H> mu- 



1 E* 



I it must not .-xc<-. d 



nion. the in. //' or In depends 



the resistance of the im.r 

 Example 17 A motor IN to work on a line having 



'"Volt- If the refMHtatlC' 



1 



