General Analysis of Speed Regulators Under Impact Loads

This paper presents the results of a generalized study that has been made on the transient speed response of basic forms of speed regulating systems to suddenly applied square wave load torques. The solutions were obtained on the transients analyzer and the electrical analogies for the systems are developed. The solutions are applicable to d-c motor drives with either variable armature voltage or motor field current control and two inherent time delays, one of which must be in the motor armature circuit. Stabilization is effected by means of an ``anticipatory´´ RC circuit just following the error signal and an RC feed-back circuit just after the first inherent time delay. The type of system specifically illustrated in the paper is one with an electronic amplifier, Rototrol, and d-c generator that supplies the armature voltage. The study shows the effects of all system parameters, including a series self-energizing field that may be used with Rototrols to eliminate steady-state speed errors. It was found practical to define optimum forms for the response to impact loading in terms of crest transient speed dip, time to recover normal speed, and per cent system damping. A set of generalized dimensionless curves presents the performance of such regulating systems in terms of these characteristics, together with the anticipation and feed-back circuit constants required for optimum solutions. These curves cover the practical range of all parameters.