Question

You want to buy three-phase asynchronous motor of 60 Hz and 480 V. You find the motor equivalent circuit parameters (IEEE model, 6 parameters) on the manufactur-er's website:
4 poles, R1 = 0.119 Ω, R’2 =0.123 Ω, Rfe = 263 Ω, X1 = 0.683 Ω, X’2 = 0.911 Ω and
Xφ = 22.8 Ω.
For operation with a slip s = 1.9%, friction and ventilation losses reach 495 W. Con-sider a positive sequence balanced supply at rated voltage.
Using the equivalent circuit and with the slip s = 1.9%, determine:
a) The impedance seen by the source motor (5 points).
b) Motor stator current (4 points).
c) Motor power factor (3 points).
d) Motor core and copper losses (4 points).
e) Motor shaft torque and mechanical power (5 points).
f) Motor efficiency (4 points).

Answer 1

a) ja,917 乙1二 O-よ ひ、IL3 2-1 6. 33 /L

Sa 6