Abstract: The reasonable design of the DC speed regulation system for cement rotary kiln is related to the stable operation of the rotary kiln. A 6 000 t/d clinker production line adopts a dual DC drive speed regulating system, which is equipped with a three winding rectifier transformer and two DC speed regulating devices. The primary winding of the rectifier transformer is connected in a triangle, one of the secondary winding is connected in a triangle, and the other is connected in a star. The two DC speed control devices directly supply power to the two DC motors. By calculating the capacity of the rectifier transformer and the starting armature current of the DC speed regulation device, the selection of equipment such as the DC speed regulation device and the main circuit breaker is carried out. The DCS control system is responsible for measuring, controlling, and protecting the dual DC speed regulation system. Since the operation of the dual DC speed regulation system, all assessment indicators are better than the contract requirements, and it is suitable for 5 000t/d and above clinker production lines.