Experimental analysis of load variation on inductor alternator operating with variable speed

In this paper the performance of inductor alternator operating with variable speed is analyzed; the effect of loading the generator on the distortion of the shape of the terminal voltage is experimentally investigated. Experimental results show that increasing the load on the generator increases the distortion of the generated voltage shape from sinusoidal. The relationship between the generated voltage and the excitation current at different operating speeds is analyzed; analysis shows that when the generator runs at the minimum speed (750 rpm), the rectified voltage at the terminals of the dc link cannot be maintained at its nominal value even with the maximum field current, the reason of that is the high distortion of the generated ac voltage which leads to significant reduction of the rectified voltage. Recommendations about reconsidering the real value of the generator gain at the design stage of the closed-loop voltage control system are given.