A $3 \phi$, six-pole, $Y$-connected synchronous generator is rated at 550 volts and has a synchronous reactance of $X_d=2.0 \Omega$. If the generator supplies $50 \mathrm{kVA}$ at a rated voltage and a power factor of 0.95 lagging, find $\mathbf{I}_s$ and $\mathbf{E}_f$ and sketch the phasor diagram for $\mathbf{V}_s, \mathbf{I}_s$, and $\mathbf{E}_f$.