The design of the torque motor is different from the general motor. The torque motor has a large starting rotation torque. It can obtain stable torque and rotation speed during low speeds or under constrained loads (reverse stable force). The torque is highest at zero speed (maximum continuous stall torque) and decreases steadily with increasing speed to keep motor and loading balanced. Motor rotation speed change is available by adjusting supply voltage when torque is constant. When the loading increases, the torque of the motor is proportional to the square of the voltage. When the torque is constant, the rotation speed can be changed by changing the supply voltage. The characteristics of the torque motor let it suitable to provide constant tension when continuous winding items, and also have continuous constant speed.