. Journal of electricity, power, and gas . ities are again the terminal values of the pressure, the cur-rent supplied to the motor, and the power-factor. In the case of the generator, the diagram for determining thevalue of the pressure, £o, to be generated for any load and anypower-factor, is the same as Fig. 1. Let us now operate this generator as a motor. £o, the pres-sure generated, is now the back e. m. f. of the motor. Let Xa bethe synchronous reactance, and n the resistance of the is the voltage applied to the motor (if £ is not constant at themotor terminals, but at some point
. Journal of electricity, power, and gas . ities are again the terminal values of the pressure, the cur-rent supplied to the motor, and the power-factor. In the case of the generator, the diagram for determining thevalue of the pressure, £o, to be generated for any load and anypower-factor, is the same as Fig. 1. Let us now operate this generator as a motor. £o, the pres-sure generated, is now the back e. m. f. of the motor. Let Xa bethe synchronous reactance, and n the resistance of the is the voltage applied to the motor (if £ is not constant at themotor terminals, but at some point on the line, then the reactanceand resistance of the line on the motor side of the point where Eis maintained constant must be added to .rt and ro). If we leave£., drawn to the right as before we must reverse E and also thecurrent, so that the motor consumes power. In Fig. 9 the ter-and the power component of the current as horizontal gives us the simple diagram to which the calculating device !.i »™tf„;„is»S g. Fig. y. Synchronous Motor Diajirani. minal pressure and current have been reversed. The terminalpressure is ao^E. I is the current delivered to the motor, and6 the angle between E and /. The pressure consumed by theresistance due to the power component of current is / cos 6 ri) =ab, and the pressure consumed by the synchronous reactance is/ cos 6 X(, = bc. ac is, therefore, the pressure consumed by theimpedance due to the power component of current. The pressureconsumed by the wattless component will be at right angles toat, to left of ac for lagging and to right for leading currents.(In the generator, lagging current consumes pressure to right ofac and leading current to left.) In Fig. 9, s«= V~r^~+~xJ^is thesynchronous impedance of the motor; and, therefore, zj sin B^cg, or eg, is the pressure consumed by the impedance of themotor by the wattless current. If the current for the load corre-sponding to ac is to be in phase with the terminal
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