Question:

If the machine in Problem (A 13.8-kV, 50-MVA, 0.9-power-factor-lagging, 60-Hz, four-pole Y-connected synchronous generator has a direct-axis reactance of 2.5 $\Omega$, a quadrature-axis reactance of 1.8 $\Omega$ , and an armature resistance of 0.2 $\Omega$ . Friction, windage, and stray losses may be assumed negligible.) is running as a motor at the rated conditions, what is the maximum torque that can be drawn from its shaft without it slipping poles when the field current is zero?