Concordia University

MECH 371

1. Objective: The objective of this experiment is to analyze and study the time response of a closed-loop DC motor speed control system and to analyze the performance of load effect of the system response. 2. Introduction: The block diagram of the closed loop speed control is show below. The feedback signal is the output velocity signal Vo (or vt), which is seen from the tachometer, which is then compared with a reference voltage Vi where error is determined by Ve=Vi-Vo. The angular velocity of the motor which is the tachogenerator is coupled directly to the end of the motor. It produces a DC voltage output Vo = Vt = Ktωm Figure 1: Basic Closed-Loop Speed Control System [1] OA 150 A (set in External Mode) will be used for signal summation and as an amplifier for adjusting proportional gain. As shown in the figure below where α is the fraction of voltage across the potentiometer, the the overall gain will be − if R1 = R2