What is the difference between static balance and dynamic balance?
When a roll is in static balance it usually implies that it is balanced to “zero rotation” where it is sufficiently balanced so that when placed in low friction bearings, it will not rotate due to imbalance. Static balancing is often specified on lower speed applications; usually less than 400 FPM depending on roll diameter and weight. When a roll is dynamically balanced, it is rotated at or above the design line speed and the imbalance is measured by and corrected in the balancing machine. There are established ISO balance tolerances which are a function of the roll mass and RPM.
