Tension control is warping, sizing, manufacturing, printing and dyeing machinery and other equipment in an important part of control, with the control technology, inverter, servo control and other new technology in the printing and dyeing equipment has also become increasingly widespread. Now most of the printing and dyeing equipment tension control in three ways, namely: inverter control. Servo control and magnetic clutch control; magnetic clutch is composed of transmission unit (input shaft) and driven unit (output shaft), between the two units, filled with granular magnetic powder about 40um in diameter, , The torque will not be transmitted from the drive unit to the driven unit; Frequency control uses the principle that the synchronous speed of the motor is linear with the frequency of the input power to convert the commercial power of 50hz to the frequency Adjustable AC power supply, the supply of three-phase asynchronous motor, to achieve speed control; servo control with a broad, smooth speed range, harder mechanical properties and good regulation, fast response, high reliability, compression Ability and other characteristics.