Question

20-pole, 200 hp, 660 V, 60 Hz, Y-connected, three-phase synchronous motors are operating at no load.
The rotor lags 0.5 degrees to the magnetic flux of the rotor with a mechanical angle,
with the induced equipment power adjusted to the same magnitude
as the phase voltage applied to the armature.
The synchronous reactance is 10 ohms and the armature resistance is 1 ohms.
Find
a) The load angle of the rotor expressed in electrical angles.
b) Armature current
c) Equivalent power and full input power.
d) Armature loss and rotational loss.

answer
a) 5 deg
b) 3.31 A
c) 1,261W, 3,783W
d) 33W, 3,750W

Answer 1