An old balanced \(\Delta\) - \(\Delta\) circuit needs to be upgraded to a \(\mathrm{Y}-\mathrm{Y}\) system. The current \(\Delta\)-connected source produces \(\mathbf{V}_{\mathrm{AB}}=\) \(2400<30^{\circ} \mathrm{V}(\mathrm{rms})\) and a positive phase sequence. The phase impedance of the load is \(Z_{\Delta}=1200<45^{\circ} \Omega /\) phase. Convert the \(\Delta-\Delta\) circuit into a balanced Y-Y system. Find the three source voltages and the phase impedance in the equivalent \(Y-Y\) circuit.