I'll iv -lirvi-vvtii v. 



in tin* total load In-ill^' ! |iiuli-- th- t'-npie- aii.i 

 xequrntly tin- current- in tli.- t\\.. mot. 



NVh.-n two dynamos are coupled mechanically -o ;i 

 run at the same speed, and are cumin -locally in 



parallel un the sam- lin.-. we hare seen that it \ powublt* 

 to run them under such conditions, that tin-re is nocurrent 

 patting either into or out of the line. In tin- condition 

 the internal loose* of the dynamos are mad.- up l>\ the 

 mechanical energy put into the combination. 



If we know the resi.-tnmvs uf the two machines, and 

 measnrf the current passing between them, then the torque 

 input is given by the c..n-i<lemtion that the mechanical 

 equivalent of the h. at low is equal to 71//.. or ' 

 From this we can writ.- lown the torque rtxjuired to rnak.- 

 up the heat loaeoe at any speed. It no\\ the tonpie 

 input is measured and proves to be greater than that 

 indicated ly the above expression, we know that the 

 difference represent* the torque in th<- two ilynamog lost 

 in friction, hysteresis, Ac. We have thus a method of 

 finding out what these loenes amount to. 



Take the case already considered ami illustrated in 

 Fit' 1". Since the rettistanc** of tin- two dynamo* are 1*2 

 and 1-09, and their induction factor* H and 1. wt have to 

 run the combination at l,l"ij r.p.m. to make th- urn nt 

 from the line not hini;; the current in each dynamo i- th. n 

 -12ani|. ingtheteTmloei we found that t 



re|uire(l to make up the heat IOAM wan 60 inch-pound*. 

 Tin- is the torque input mi the :iM.timpiii.n th.it the 

 only losses to be made up are the heat losses ; if, however, 

 there are friottonal and other torque louse* as w.-ll. 

 pp.- input muM )N> greater than GO inch-noun. I- ; 

 H up !> that w.- found if to be HO inch-|i>iundi(. then we 



u 2 



