94 



SYNCHRONOUS MOTORS 



third, all the load-losses produced by the impedance z; this latter 

 being represented by a vector BAi = zI (Fig. 44) which makes the 

 angle <f> with a line ED that is itself drawn at an angle d with OA 2 

 such that 



The line BA\ can serve to define the current 7, in magnitude and 

 in phase, if B Y be taken as the axis of reference, with a scale Z times 

 greater than the scale of volts. 



This vector zl can be resolved into two E.M.F.'s, viz.: 

 BD=zI w , produced by the active current, and DA = zI d , produced by 

 the reactive current. 



The line A 2 D, closing the triangle A%BD, then represents the 

 combination of the reaction E.M.F.'s due to the active current, and it 

 makes, with OX, the angle f defined by the equation 



(/ + /) 



tan = 



R 



[It will be noted that the diagram differs from the preceding by the 

 definitions of z and d, which do not include the motor-reactance.] 

 Moreover, we will have 



