When sourcing a welding tank rotator, the most critical factor is the loading capacity, which must exceed the maximum weight of your heaviest workpiece by at least 20% to ensure a safety margin. You should also evaluate the diameter range (the minimum and maximum vessel sizes the rollers can accommodate) and the drive motor power. Look for units equipped with stepless speed regulation (usually via Variable Frequency Drive/VFD) to ensure smooth rotation speeds, typically ranging from 100 to 1000 mm/min, which is essential for high-quality welding seams.