Synchronous Machines. Determining leading or lagging power factor.

Thread Starter


Joined Jan 10, 2017
Hi, I have been trying to solve this question but not able to get the answers or understand why these answers are valid ?

A synchronous generator rotates at a speed of 1200 rpm and delivers 100 kVA to a load with a power factor of 0.85. The terminal voltage is equal to 560 V. The phase flux linkage of the generator is equal to 0.45 Wb, the number of poles is 10. The generator is assumed lossless.
a) Draw Phasor Diagram (Ans ==> Ia leads both E (emf) and Va(terminal voltage) ; E leads Va )
b) Calculate Torque angle (18.19 degees)
c) Calculate Synchronous Reluctance (0.0016 Henry)

How is Ia leading both E and Va, I understand that since this is a generator E leads Va ?
How do you determine in such cases (for both motor and generator) whether power factor is lagging or leading and whether Ia lags E or leads it ?

Thanks :)