The equivalent-circuit parameters in ohms per phase referred to the stator for a two-phase, 1.0 kW, 220-V, four-pole, 60-Hz, squirrel-cage induction motor are given below. The no-load rotational loss is 65 W. R₁ = 0.78 R₂ = 4.2 X₁ = X₂ = 5.3 X_m = 93

a. The voltage applied to phase c~ is 220 < 0° V and that applied to phase β is 220 < 65° V. Find the net air-gap torque at a slip s = 0.035.

b. What is the starting torque with the applied voltages of part (a)?

c. The applied voltages are readjusted so that V_α = 220 < 65° V and V_α = 220 < 90° V. Full load on the machine occurs at s = 0.048. At what slip does maximum internal torque occur? What is the value of the maximum torque?

d. While the motor is running as in part (c), phase β is open-circuited. What is the power output of the machine at a slip s = 0.04?

e. What voltage appears across the open phase-β terminals under the conditions of part (d)?