The application of the inverse Nyquist array method is proposed for the improvement of the dynamic response of a turbo-alternator. This approach is computationally more attractive than optimal control, output-feedback or state feedback decoupling and pole assignment which have recently been applied to the control of a single machine system. It results in a simpler control scheme and also provides insight into the interaction and phase lags present in the system. The steam-flow and excitation controllers are designed in isolation after achieving diagonal dominance and their combined operation results in a stable, diagonally dominant system with improved dynamic response. A new method is also proposed for maintaining diagonal dominance in the overall system subject to small parameter variations.