
92 Shipboard Electrical Power Systems
Example 4.7
A 100 MVA, 4-pole, 60 Hz synchronous generator that operates at 0.90 power
factor load has a cylindrical rotor 5 m long and 1.5 m in diameter. The aver-
age mass density of the rotor’s copper and magnetic steel combined is 8 g/cm
3
.
Determine the kinetic energy of the generator rotor running at the rated speed.
Assuming that the turbine rotor has inertia 1.5 × generator rotor inertia, determine
the inertia constant H of the turbine-generator system.
SOLUTION
Rated speed of 4-pole, 60 Hz generator = 120 × 60 ÷ 4 = 1800 rpm.
∴ ω
mech
= 2π × 1800 ÷ 60 = 188.5 rad/sec.
Polar moment of inertia ...