6-23. A 460-V four-pole 75-hp 60-Hz Y-connected three-phase induction motor develops its f...

6-23. A 460-V four-pole 75-hp 60-Hz Y-connected three-phase induction motor develops its full-load induced torque at 3.5 percent slip when operating at 60 Hz and 460 V. The per-phase circuit model impedances of the motor are

Mechanical, core, and stray losses may be neglected in this problem.

(a) Find the value of the rotor resistance R2.

(b) Findand the rotor speed at maximum torque for this motor.

(c) Find the starting torque of this motor.

(d) What code letter factor should be assigned to this motor?