Reversible Operation System of the DC Motor Using Only One Thyristor and It's Characteristics

Abstract

Recently, the speed control systems using DC motor with thyristor are employed in many industries, since they have many advantages compared with the conventional motor-generator speed control system.
On the other hand, to realize the reversible direction of rotation of the DC motor, we must have the circuit construction which can change the direction of field or armature current.
Various circuits are worked out to accomplish this purpose, for example, the one uses plural thyristor, the other adopts the split-field having the large time constant, the third makes use of the change-over mechanical contact, etc.
In this paper, the reversible speed control system with single thyristor is explained, and it's static and dynamic characteristics are measured and discussed. In this control system, the speed of the DC motor is controlled by the gate signal and the rotational direction of the motor is controlled by the unbalanced current between the direct current and the reverse current discharged from the inductive element in the armature.
The speed-torque characteristics of the above mentioned system is approximately linear and the response time is not so large compared with that of the DC motor drived by DC power supply.