How to change the speed of dc motor controller

The speed of dc motor controller can control and adjust, you know? Said by below small make up to you about my change method of dc motor speed controller. 1. The armature voltage: this is a constant torque control method, by changing the armature voltage, make the speed change, has the advantages of quick dynamic response, so suitable for a wide range of stepless smooth speed regulation system. 2. Change the dc motor controller: the main magnetic flux by weakening magnetic flux of dc motor controller, let its speed rising from the rated speed, this way belongs to the constant power speed regulation method, on the dynamic response is slower, although can be stepless smooth speed regulation, but the speed range is small. Above all, everyone knows how to change the dc motor speed controller is.