The paper describes the design, construction and testing of a closed-loop system for the speed control of a separately excited d.c. motor fed from a dual converter. The dual converter makes possible regenerative braking and reversal of direction of rotation. There is only one firing unit and the firing pulses are diverted to the appropriate converter by a master controller. There are three control loopsi one for armature current control, one for adjusting the firing angle of the oncoming converter, and one for speed control. Proportional plus integral type of controllers have been used to achieve good dynamic and steady-state responses. Experimental results are given and compared with theoretical ones. © 1976, IEEE. All right reserved.