The relation of the tension with strip tension torque,friction windage torque and dynamic torque was analyzed by using the principle of DC motor drive,and a mathematic model for tension control was set up.

This paper analyzes the mechanical characteriseics of YD range of pole-changing adjustable-speed motors with Y/YY connections, and gives suggestions based on analyzing different methods for drawing mechanical characteristics, which have some reference for both scientific research personnel being engaged in motor drive and user.

It can serve as an important element in control circuit of motor drive.