A high-power servo analyzer

IN the design of a closed-loop control system, it is necessary to study the dynamic characteristics of the control circuit and its components to determine their effect upon accuracy, speed of response, and stability. While the advent of analogue computers has greatly simplified these studies, difficulties are encountered in setting up analogues that incorporate the same nonlinearities and operate at the same power levels as the equipment involved. To provide a means of obtaining more accurate information, the special high-power servo analyzer described in this paper was designed and constructed; see Fig. 1. Its function is to determine the frequency response curves, both magnitudes and phase shifts, of actual apparatus operating at normal power level. This servo analyzer has been used to study the characteristics of aircraft electric generating systems; however, it could be employed in the design of any type of control system. Thus, the development of the servo analyzer adds another design tool to those already available for control system design.