Self-Aligning welding rotator for the circular cylinder of welding, polishing, pad and on-site assembly use and according to the size of a large cylinder within the framework of self-regulation, the general tonnage of plastic combined with steel rollers, large tonnage steel roller used, load capacity, stable and reliable; control section can be used or electromagnetic frequency conversion speed, speed range, torque, long life; to facilitate the operation also has a remote control box.