Performance of a Chopper-Controlled DC Drive with Elastic Coupling and Periodically Varying Load Torque

A chopper-fed separately excited direct current (dc) motor driven electromechanical system is analyzed. The influence of inherently present elasticity of the shaft on the performance of the drive with a load torque periodic in nature is investigated. A mathematical model of the system is given and the equations are solved using a noniterative technique. Closed-form solutions for system performance in terms of motor current and speed, in transient as well as steady state conditions, are obtained. Conditions leading to the possibility of resonance are discussed. Results are illustrated by an example, and inferences are drawn.