SYNCHRONOUS MOTOR (part 2) The steady-state characteristics of a
synchronous motor represented by phasor diagrams are shown as
function of the load P with the excitation voltage E kept
constant. The power expression is P = I V cos(φ) = E V sin(δ) /
X. The basic phasor equation is V = E + jX I. The locus of E is
a portion of a circle of radius E centered at the origin of the
complex plane. The locus of I is also a circle of radius E/X
centered on the imaginary axis at –V/X. The power P versus the
torque angle δ is also plotted.