Dynamic Characteristics of a DC Motor Controlled by Single-Phase Half-Wave Thyristor Rectifier Circuit (II)

Abstract

When the armature voltage of a dc motor is being controlled by a singlephase half-wave thyristor rectifier circuit, the armature current flows discontinuously, but the motor speed scarcely fluctuates during one cycle of an ac supply frequency. Hence, the authors analyse the static and dynamic characteristics of the dc motor for the case where it is assumed that the fluctuation of the motor speed is negligible. In the analysis, they consider the effects of the motor brush and thyristor internal voltage drops on the characteristics, which can't be neglected when the motor is driven with a low voltage supply. Next, they compare the theoretical results with the experimental ones ; and then investigate the effects of circuit parameters on the characteristics of the motor. Finally, they make a study of the dissipated power, efficiency and frequency response in the circuit, which have not been investigated in the usual papers.