Stabilizing elements in aircraft D-C systems

TWO RECENT STUDIES of aircraft generator regulator systems have come from this laboratory. One1 analyzed the carbon-pile regulator and determined its transfer function; the other2 derived a generator-transfer function and determined stability criteria for a regulator-generator combination. These studies were concerned primarily with design parameters of the regulator and generator but did not answer the question of how to improve matters once the regulator and generator design were fixed. In particular, an understanding of the function and limitations of the standard feedback resistor was desired. Therefore, a mathematical and experimental investigation was undertaken to obtain the transfer functions of systems with feedback. The mathematical determination of these functions was straightforward. They were, however, too cumbersome and complicated in their exact form to be of great help in noting the effect of changes of parameters, primarily because there are no buffer amplifiers allowable between components. In some cases, but not all, reasonable approximations have been derived. There are, however, mathematical generalizations in the frequency plane one can fall back upon for the purpose of understanding or designing stabilizing networks. These generalizations, in addition to transfer-function measurements, form the basis of work which has been done here.