Method of and apparatus for balancing a rotary body

A method of and apparatus for balancing a rotary body is disclosed. The apparatus includes an unbalance detection unit which rotates the body in first and second spaced bearings, the location of the first and second bearings defining first and second bearing planes, respectively. The forces developed by rotation of the body are sensed at the first and second bearing planes and the forces about the first bearing plane are summed to determine the weight and angular location of a mass compensation which, if effected, would substantially statically balance the body. An iterative technique is utilized which determines the axial location of the mass to be removed or added which would reduce to a minimum the dynamic unbalance of the body. The body is then passed to an unbalance correction unit which removes or adds the mass at the determined angular and axial locations to minimize the static and dynamic unbalances. Should a single addition or removal of mass be insufficient to reduce the dynamic unbalance to an acceptable level, additional mass compensations can be carried out to minimize the unbalance.