of the Compound Dynamo. 465 
though, from the more general meaning assigned to the con- 
stants, they are in reality of a more general character. 
Let us now apply them to the compound dynamo. Of 
the two forms of this machine, which, following the example 
of Prof. 8. Thompson, we may call the Short-Shunt and the 
Long-Shunt respectively, we will take the former first. 
Short-Shunt Compound Dynamo. 
In this case 7, =p.>=0. 
The conductors p; and p, represent the series- and shunt- 
coils, and 7, represents the external resistance. 
A 
Tz 
Pp 
Z 
Hence 
| io wee [oh <oel 
Ri =py 2=1o; 
alla tes ‘aT Pa aPa 
Rear, + Paltat es) _ at pi)(ra+ pa) + rapa 
TT Pit Pa Tot Pi + Pa 
+ pi Pa 
s={ oe +s } . 
Pa : T2 + Pi + Pa 
Neglecting k, we get 
pe 1 {nM— (72+ p1)(Pa + pa) + Papa U 
o Sa(%2 + p1) + 51P a 
Again, since 
2. —_ 1D and 2 — Ya S= Lv Rea aae 
C919 CaR i £ Lo + Pi + Pa 
ToT P, Pa (72+ P1)Pa 
Fag, Tae Ord 
Pa "2 
= (12 a pi)(%a a5 Pa) of TaPa. 
Y2Pa 
ol = nMrpa 
2 o L r2(7a+ Pa) + Pat Pa) + Tapa 
Whence 
ruse V2Pa i 
Sa =e (Sap1 == S1Pa) : 
