Curtain fabric electric synchronous motor was used as a power communicate with crawler gear installed in the transmission gear box, through the end of the NW type motor variable speed planetary power transmission will be tracked. Track was found in the special structure of the aluminum track, the track is a high-strength low-elongation polymeric materials, in whole life has been in a state of elastic deformation; the other side of the electrical control box are a group of planets through gear directly transmitted to the two-bit bad with the structure of the planet wheel transmission system and control of two micro-contacts and disconnect switch, thereby to control and stop the motor rotation. Dual-winding motor winding capacitance operation mode, control the work of two-winding, so as to enable synchronous motor is to achieve and reverse. Motor and gearbox with a lock-chip using the parallel port connection, the electrical and power contacts between the use of self-locking plug connected to the installation, repair and adjust a great convenience. The abolition of the electrical circuit system of traditional del limit switch, which obviates the need to connect wires back and forth, so that the whole curtain rail clean up simple. The largest electric transmission system at 17 meter distance limit.