CALCULATION OF A SINGLE-PHASE CURRENT MOTOR. 



115. Leakage. The leakage coefficient is 0.061 for the iron frame, 



116. Idle Current. We have according to (13) : 



(13). 



im ' 1 + 2 



2 -f- 2 a 



1 + 0.122 



2 + 0.122 



- 0.576 



/ = 20.8 amperes. 



117. Friction. Loss through friction and air resistance, 2150 watts. 



118. We can now draw our standard diagram. This has been done 

 in Fig. 33. The ordinates measured between the full line curve and 



FIG. 33. 



the basis of the semi-circle measure the output of the motor for the 

 armature with small resistance. The ordinates between the broken 

 line curve and the basis of the semi-circle measure the output of the 

 motor for the squirrel cage armature. 



65 



